Merge main

fix(run): run PHP files with the interpreter chosen in Settings
Running a .php file (or a #!/usr/bin/env php script) produced a configuration with the PATH php: the file producer looked tools up on PATH, and the settings pass only replaces a bare "php" command, never the absolute path the producer had resolved. With [email protected] selected in Settings and php 8.4 on PATH, the file ran on 8.4, and with no php on PATH it failed to start although an interpreter was selected. A new sdk_php_effective command returns the configured interpreter, the way sdk_python_effective does for Python, and the producer prefers it. The not-found message now also points to the PHP settings page.
2026-11-07 17:22:55 -10:00 · 2026-11-05 23:46:55 +08:00 · 2026-11-05 23:46:28 +08:00 · 2026-11-05 23:41:44 +08:00 · 2026-11-05 23:39:40 +08:00 · 2026-11-05 23:38:03 +08:00
1811 changed files with 197565 additions and 10848 deletions
@@ -0,0 +1,91 @@
+---
+name: issue-fix
+description: Triage and fix a GitHub issue (or a user-reported bug) end to end — reproduce, find the root cause, generalise it to every sibling case, fix the class rather than the instance, verify, and open one PR. Use when given an issue URL/number or asked to fix a reported bug and open a PR ("看看这个 issue", "修一下这个 bug", "提 pr").
+---
+
+# Fix an issue: from one case to the whole class
+
+The reported case is one sample of a defect class. A fix that only makes the
+screenshot go away is not done: the next question is always "does this break for other
+languages / platforms / entry points too?". Answer that before anyone asks.
+
+## 1. Read and reproduce
+
+- `gh issue view <n> --comments` (repo `l0ng-ai/openidea`). Read attached logs/screenshots
+  closely: OS, language, toolchain versions, exact error text.
+- Locate the code path and confirm the claim in code, with `file:line` evidence.
+  Say plainly whether it is a real bug, a missing feature, or user environment.
+- Reproduce locally when possible (`fixtures/` projects, `/verify` for runtime). If the
+  reporter's platform (often Windows/Linux) can't be reproduced here, say so up front.
+- Do not ask for a generic environment/log checklist before trying the flow and inspecting the code.
+  Record the attempt and result; ask only for a fact that actually blocks the next diagnostic step.
+  Missing fields, limited time, or unavailable automation are not by themselves reasons to ask the reporter.
+- Treat a maintainer-confirmed bug as an investigation task even if local reproduction fails. Distinguish
+  “not reproduced here” from “not a bug”, and do not require the reporter to prove its existence again.
+
+## 2. Name the root cause as a class
+
+Write one sentence of the form "<mechanism> is missing/wrong, so any <X> hits it",
+not "<this button> is broken". Typical classes in this codebase:
+
+- Per-language config handled for one language only (`languages/*.toml`, `ide-sdk`).
+- Platform gaps: paths, executables, shells, `.cmd`/`.exe`, separators — macOS-only code.
+- Toolchain/version discovery: one probe location, no version check, no rescan.
+- Two features each implementing half a flow and never joined (feature isolation →
+  should go through an action/service).
+- State not reset on project switch / window reuse; events not scoped per window.
+- Failure surfaced as raw stderr/stack trace or retried until "crashed" instead of a
+  clear status with an action.
+- UI: same primitive styled differently in N places.
+
+## 3. Sweep for siblings
+
+Search systematically, not by memory:
+
+- Same pattern elsewhere: `git grep` the function, the config key, the error string,
+  the hard-coded path/flag. Check every `languages/*.toml` entry and every platform branch.
+- Same flow for other languages/runtimes (Java ↔ Kotlin/Gradle, Python ↔ venv/uv,
+  Node ↔ Deno/Bun, Go, Rust …): would they fail the same way?
+- Other callers/entry points of the same flow (menu, context menu, gutter, shortcut, CLI arg).
+- Neighbouring failure modes of the same mechanism (not installed / wrong version /
+  installed but crashes / slow start / installed mid-session).
+  For broad sweeps spawn one Explore agent with the class description, not the instance.
+
+## 4. Decide the fix at the right altitude
+
+- Fix the mechanism once (shared helper, action, config hook) so siblings are fixed
+  by construction; don't patch each call site.
+- Respect `AGENTS.md` rules (crate boundaries, no cross-feature imports, `IdeResult`,
+  UTF-16). If the right fix breaks a rule, pick the rule-respecting design and say why.
+- Compare with how established IDEs solve it when relevant; prefer the established answer.
+- Present: root cause, sibling table, proposed fix, what's deferred. When the user leaves
+  the choice to you, go ahead without asking again.
+
+## 5. Implement and test the class
+
+- Tests cover the class: table-driven over languages/platforms/states, not just the
+  reported input. Include the reporter's case verbatim.
+- Run the scoped checks (`pnpm vitest run <path>`, `cargo nextest run -p <crate>`), then
+  `/verify` in the app for UI or runtime behaviour.
+
+## 6. PR
+
+- One branch `fix/<slug>`, one PR unless the user asks otherwise; `Fixes #<n>` in the body.
+- Don't stage untracked IDE-state dirs (`.ideal/`, `.openidea/`) or screenshots.
+- PR body follows `.github/pull_request_template.md`: `Closes #<n>`, then
+  **What and why** (user-visible change + root cause at class level, 2–4 sentences),
+  **How it was verified** (commands run and results, siblings fixed/deferred, what could break and how
+  it was checked, what was not verified, e.g. "Windows not tested"; for UI changes the before/after
+  screenshot paths from `/verify`), **Review focus** (optional). Short and plain.
+
+## Report format
+
+Reply in the user's language:
+
+```
+Root cause: <one sentence, class level>
+Sibling sweep:
+| Location / case | Affected? | Action |
+Fixed / not covered (why) / not verified (platform)
+PR: <url>
+```
@@ -0,0 +1,57 @@
+---
+name: verify
+description: Build, launch and drive the OpenIDEA desktop app through the Tauri MCP bridge to verify a change at runtime.
+---
+
+# Verify OpenIDEA in the running app
+
+## Launch
+
+- Run the app from the worktree that holds the change: `pnpm tauri dev` in the background, logging
+  into your task's scratch subdirectory. Use `pnpm dev:app` instead when your checks call
+  `window.__TAURI__` from `execute_js`. The wrapper gives each worktree its own app identity, data,
+  settings and Vite port, so other worktrees and the installed app don't interfere. If it reports a
+  session already running for this worktree, reuse that one.
+- Once the app is up, `pnpm dev:status` lists this worktree's MCP bridges. Pass the reported
+  `appIdentifier` (the port) on every `mcp__tauri__*` call. The MCP server is shared between
+  sessions: never `driver_session stop` without an `appIdentifier`, and re-check `document.title` /
+  `location.href` before acting if anything looks off.
+- Make sure the binary contains the change: a session already running for this worktree may be an
+  older build. Restart it after Rust changes; frontend changes reload through Vite.
+- After the app restarts, `driver_session start` again for your port (a stale session says "Already connected").
+- If the `pnpm tauri dev` process exits while the app window stays open, Vite is gone and any webview
+  reload shows an empty `#root`. Stop that app and start the session again.
+- Stop everything you started when done and nothing else; never use process-name kills.
+
+## Driving
+
+- `manage_window focus` before screenshots / timing-sensitive steps: a background window throttles timers
+  (debounced LSP / VCS refreshes stall, `setTimeout` promises in `execute_js` time out) and native
+  screenshots come back black.
+- Settings is a separate native window `settings-main`; pass `windowId`, focus it before screenshotting.
+- CodeMirror / xterm ignore MCP `type`. Focus the element, then `document.execCommand('insertText', false, text)`.
+  For xterm Enter, dispatch a `keydown` (`key: 'Enter', keyCode: 13`) on `.xterm-helper-textarea`.
+- MCP clicks arrive with `event.detail === 0`; CodeMirror treats them as line-select clicks. Set the caret
+  through the view instead: `document.querySelector('.cm-content').cmTile.view`.
+- MCP `text` strategy can resolve to a hidden node; prefer coordinates (CSS px = image px × 0.9) or CSS selectors.
+- CSS-module edits often trigger a full page reload in dev: dialogs close, Run sessions and terminal
+  scrollback reset, and each reload spawns a fresh shell. Re-open what you were testing.
+
+## Evidence
+
+- For UI or interaction changes, capture `before.png` (on `main` or with the fix reverted) and
+  `after.png` at the same state and window size, into your task's scratch subdirectory. Multi-step
+  flows: a numbered series (`after-1.png`, `after-2.png`, ...).
+- Report the absolute paths; they go into the PR's **How it was verified** section and the triage
+  acceptance entry. Never commit screenshots to the feature branch.
+
+## Fixture
+
+`fixtures/` has sample projects (go-app, rust-app, ts-app, kotlin-gradle, polyglot). Copy one into
+your scratch directory before editing it, and don't commit the IDE state it creates (`.openidea/`).
+
+## Flows worth driving
+
+⌘⇧O Goto File · ⌘⇧F Find in Files (preview scroll + highlight) · ⌘⇧A Find Action · editor edit/undo/autosave ·
+Terminal (Unicode, venv) · Commit view at the default narrow width · Problems · Run → Stop · Project view
+New / Delete (nested `a/b.txt` names) · ⌘, Settings search (+ Keymap filter) · Git Log on a repo without commits.
@@ -0,0 +1 @@
+../../.agents/skills/issue-fix
@@ -0,0 +1 @@
+../../.agents/skills/verify
@@ -0,0 +1,75 @@
+name: Bug report
+description: Something in OpenIDEA doesn't work as expected
+labels: [bug]
+body:
+  - type: markdown
+    attributes:
+      value: |
+        Thanks for reporting! Keep logs and error messages exactly as they appear.
+
+        One problem per issue, please. If you have several, open one issue for each.
+  - type: checkboxes
+    id: checks
+    attributes:
+      label: Before you start
+      options:
+        - label: I searched [existing issues](https://github.com/l0ng-ai/openidea/issues?q=is%3Aissue) and this hasn't been reported yet.
+          required: true
+        - label: I'm on the [latest release](https://github.com/l0ng-ai/openidea/releases/latest), or I noted below that I can't update.
+          required: true
+  - type: textarea
+    id: environment
+    attributes:
+      label: Environment
+      description: |
+        Open **About OpenIDEA** (macOS: OpenIDEA menu; Windows/Linux: Help menu), click **Copy Info**, and paste it here. Also mention the project type if it matters (e.g. Gradle multi-module, Spring Boot, Go workspace) and whether you use remote development.
+      render: text
+      placeholder: |
+        About OpenIDEA
+        Version: 0.1.33
+        Build: ...
+        Platform: macOS aarch64
+    validations:
+      required: true
+  - type: textarea
+    id: steps
+    attributes:
+      label: Steps to reproduce
+      description: Start from opening OpenIDEA or a project. A small sample project or snippet helps a lot.
+      placeholder: |
+        1. Open a Gradle project whose settings.gradle includes modules in a loop
+        2. Open the Gradle tool window
+        3. ...
+    validations:
+      required: true
+  - type: textarea
+    id: reproduction
+    attributes:
+      label: Minimal reproduction
+      description: A link to a small public repository, or the smallest files/snippet that trigger the problem. Optional, but it's the fastest way to get a fix.
+      placeholder: https://github.com/you/repro-project
+  - type: textarea
+    id: expected
+    attributes:
+      label: Expected behavior
+    validations:
+      required: true
+  - type: textarea
+    id: actual
+    attributes:
+      label: Actual behavior
+      description: What happened instead. Screenshots or a recording are welcome.
+    validations:
+      required: true
+  - type: textarea
+    id: logs
+    attributes:
+      label: Logs
+      description: |
+        Use **Help → Show Log in Finder / Explorer / Files** to find `openidea.log` and paste the lines around the problem, or attach the file. Include console output or error messages too. Check for tokens or passwords before posting.
+      render: text
+  - type: textarea
+    id: extra
+    attributes:
+      label: Additional context
+      description: Anything else, such as whether it worked in an earlier version.
@@ -0,0 +1,5 @@
+blank_issues_enabled: false
+contact_links:
+  - name: Download the latest release
+    url: https://github.com/l0ng-ai/openidea/releases/latest
+    about: Many problems are already fixed. Please check the latest version before reporting.
@@ -0,0 +1,48 @@
+name: Feature request
+description: Suggest a new feature or an improvement
+labels: [enhancement]
+body:
+  - type: markdown
+    attributes:
+      value: |
+        One request per issue, please.
+  - type: checkboxes
+    id: checks
+    attributes:
+      label: Before you start
+      options:
+        - label: I searched [existing issues](https://github.com/l0ng-ai/openidea/issues?q=is%3Aissue) and this hasn't been requested yet.
+          required: true
+  - type: textarea
+    id: problem
+    attributes:
+      label: Problem
+      description: What are you trying to do, and what gets in the way today?
+    validations:
+      required: true
+  - type: textarea
+    id: proposal
+    attributes:
+      label: Proposed solution
+      description: How you'd like it to work. Mockups or examples from other tools are welcome.
+    validations:
+      required: true
+  - type: textarea
+    id: acceptance
+    attributes:
+      label: Acceptance criteria
+      description: How we'll know it's done. One observable behavior per line.
+      placeholder: |
+        - [ ] Right-clicking a test class shows "Run with Coverage"
+        - [ ] Coverage results open in the Coverage tool window
+    validations:
+      required: true
+  - type: textarea
+    id: alternatives
+    attributes:
+      label: Alternatives and workarounds
+      description: Other approaches you considered, or what you do now instead.
+  - type: textarea
+    id: extra
+    attributes:
+      label: Additional context
@@ -0,0 +1,18 @@
+<!-- If this resolves an issue: Closes #<n> -->
+
+## What and why
+
+<!-- 2–4 sentences: the change a user notices, and the root cause.
+     If it doesn't fit, the PR is probably too big; split it. -->
+
+## How it was verified
+
+<!-- Required. Commands you actually ran and their results; what else this could
+     affect and how you checked it still works.
+     Visible UI changes: before/after screenshots (not for removed UI or copy-only
+     changes). Multi-step interactions: a recording.
+     Backend changes: logs or command output. -->
+
+## Review focus
+
+<!-- Optional: anything you want reviewers to look at closely. -->
@@ -7,6 +7,9 @@ on:
    types: [opened, synchronize, reopened]
  workflow_dispatch:

+permissions:
+  contents: read
+
 concurrency:
  group: ci-${{ github.ref }}
  # A newer push supersedes the run in progress, on main too.
@@ -15,20 +18,64 @@ concurrency:
 env:
  CARGO_TERM_COLOR: always
  CARGO_INCREMENTAL: 0
+  # Line tables keep test backtraces readable; full debuginfo only adds build time and cache size.
+  CARGO_PROFILE_DEV_DEBUG: line-tables-only

 jobs:
+  # Which parts a pull request touches, so jobs it can't affect skip and leave the
+  # shared runners to others. Pushes and manual runs always run everything.
+  changes:
+    name: Changes
+    runs-on: ubuntu-latest
+    timeout-minutes: 5
+    permissions:
+      pull-requests: read
+    outputs:
+      rust: ${{ steps.classify.outputs.rust }}
+      frontend: ${{ steps.classify.outputs.frontend }}
+    steps:
+      - id: classify
+        env:
+          GH_TOKEN: ${{ github.token }}
+          PR: ${{ github.event.pull_request.number }}
+        run: |
+          set -euo pipefail
+          if [ "$GITHUB_EVENT_NAME" != pull_request ]; then
+            echo "rust=true" >> "$GITHUB_OUTPUT"
+            echo "frontend=true" >> "$GITHUB_OUTPUT"
+            exit 0
+          fi
+          gh api --paginate "repos/$GITHUB_REPOSITORY/pulls/$PR/files" \
+            --jq '.[] | .filename, (.previous_filename // empty)' > files.txt
+          cat files.txt
+          docs='^(docs/|\.agents/|\.claude/|\.idea/|\.github/ISSUE_TEMPLATE/|\.github/pull_request_template\.md$|[^/]+\.md$|LICENSE$|NOTICE$)'
+          # Frontend-only paths. The Rust code embeds a few files under src/; those stay out.
+          web='^(src/|e2e/|perf/|public/|scripts/|smoke/|index\.html$|vite\.config\.ts$|tsconfig[^/]*\.json$|knip\.ts$|playwright\.config\.ts$|\.oxlintrc\.json$|\.oxfmtrc\.json$)'
+          embedded='^src/(bindings\.ts|styles/tokens\.css|features/plugins/views/frame-bridge\.js|platform/keymaps/)'
+          # A job runs when any changed file falls outside the paths that can't affect it.
+          rust=false
+          if grep -Ev "$docs|$web" files.txt | grep -q . || grep -Eq "$embedded" files.txt; then rust=true; fi
+          frontend=false
+          if grep -Ev "$docs" files.txt | grep -q .; then frontend=true; fi
+          echo "rust=$rust frontend=$frontend"
+          echo "rust=$rust" >> "$GITHUB_OUTPUT"
+          echo "frontend=$frontend" >> "$GITHUB_OUTPUT"
+
  rust:
    name: Rust (${{ matrix.os }})
+    needs: changes
+    if: needs.changes.outputs.rust == 'true'
+    timeout-minutes: 60
    strategy:
      fail-fast: false
      matrix:
        os: [macos-latest, ubuntu-22.04, windows-latest]
    runs-on: ${{ matrix.os }}
    steps:
-      - uses: actions/checkout@v4
-      - uses: pnpm/action-setup@v4
+      - uses: actions/checkout@v5
+      - uses: pnpm/action-setup@v5
        with: { version: 11 }
-      - uses: actions/setup-node@v4
+      - uses: actions/setup-node@v5
        with: { node-version: 22, cache: pnpm }
      - uses: dtolnay/rust-toolchain@stable
        with: { components: "clippy, rustfmt" }
@@ -60,9 +107,12 @@ jobs:
  # keep that build working.
  server:
    name: Remote server (linux musl)
+    needs: changes
+    if: needs.changes.outputs.rust == 'true'
+    timeout-minutes: 40
    runs-on: ubuntu-22.04
    steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
      - uses: dtolnay/rust-toolchain@stable
        with: { targets: x86_64-unknown-linux-musl }
      - uses: Swatinem/rust-cache@v2
@@ -71,23 +121,83 @@ jobs:
      - run: cargo build --locked -p ide-host --bin openidea-server --target x86_64-unknown-linux-musl
      - run: target/x86_64-unknown-linux-musl/debug/openidea-server --version

+  # The plugin SDK, the official plugins and the test fixtures build in their
+  # own workspaces (the root excludes them), so the jobs above don't see them.
+  plugins:
+    name: Plugins (SDK, official, fixtures)
+    needs: changes
+    if: needs.changes.outputs.rust == 'true'
+    timeout-minutes: 30
+    runs-on: ubuntu-22.04
+    env:
+      CARGO_TARGET_DIR: ${{ github.workspace }}/target-plugins
+    steps:
+      - uses: actions/checkout@v5
+      - uses: dtolnay/rust-toolchain@stable
+        with: { targets: wasm32-wasip2, components: "clippy, rustfmt" }
+      - uses: Swatinem/rust-cache@v2
+        with:
+          key: plugins
+          cache-directories: target-plugins
+          save-if: ${{ github.ref == 'refs/heads/main' }}
+      - name: Format, lint (host and wasm) and test each crate
+        shell: bash
+        run: |
+          set -euo pipefail
+          for dir in sdk/rust/openidea-plugin plugins/official/*/ crates/ide-plugin/tests/fixtures/*/; do
+            [ -f "$dir/Cargo.toml" ] || continue
+            echo "::group::$dir"
+            cargo fmt --check --manifest-path "$dir/Cargo.toml"
+            cargo clippy --locked --all-targets --manifest-path "$dir/Cargo.toml" -- -D warnings
+            cargo clippy --locked --target wasm32-wasip2 --manifest-path "$dir/Cargo.toml" -- -D warnings
+            cargo test --locked --manifest-path "$dir/Cargo.toml"
+            echo "::endgroup::"
+          done
+      - uses: pnpm/action-setup@v5
+        with: { version: 11 }
+      - uses: actions/setup-node@v5
+        with: { node-version: 22 }
+      # Plugin web pages (`web-src/`, their own pnpm projects): typecheck and test.
+      - name: Web pages typecheck and test
+        shell: bash
+        run: |
+          set -euo pipefail
+          for dir in plugins/official/*/web-src/; do
+            [ -f "$dir/package.json" ] || continue
+            echo "::group::$dir"
+            pnpm --dir "$dir" install --frozen-lockfile --ignore-workspace
+            pnpm --dir "$dir" exec tsc --noEmit
+            pnpm --dir "$dir" test
+            echo "::endgroup::"
+          done
+      # The host's tests run the checked-in components: they must be built from these sources.
+      # Web pages aren't checked in: this builds them and checks the result.
+      - name: Checked-in components are up to date, web pages build
+        run: plugins/build.sh --check
+
  deny:
    name: Cargo deny
+    needs: changes
+    if: needs.changes.outputs.rust == 'true'
+    timeout-minutes: 15
    runs-on: ubuntu-latest
    steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
      - uses: dtolnay/rust-toolchain@stable
      - uses: taiki-e/install-action@cargo-deny
      - run: cargo deny check

  frontend:
    name: Frontend
+    needs: changes
+    if: needs.changes.outputs.frontend == 'true'
+    timeout-minutes: 30
    runs-on: ubuntu-22.04
    steps:
-      - uses: actions/checkout@v4
-      - uses: pnpm/action-setup@v4
+      - uses: actions/checkout@v5
+      - uses: pnpm/action-setup@v5
        with: { version: 11 }
-      - uses: actions/setup-node@v4
+      - uses: actions/setup-node@v5
        with: { node-version: 22, cache: pnpm }
      - run: pnpm install --frozen-lockfile
      - run: pnpm typecheck
@@ -99,20 +209,23 @@ jobs:

  e2e:
    name: E2E
+    needs: changes
+    if: needs.changes.outputs.frontend == 'true'
+    timeout-minutes: 30
    runs-on: ubuntu-24.04
    # Browsers and their system libraries are preinstalled; keep the tag in step with @playwright/test.
    container: mcr.microsoft.com/playwright:v1.64.1-noble
    steps:
-      - uses: actions/checkout@v4
-      - uses: pnpm/action-setup@v4
+      - uses: actions/checkout@v5
+      - uses: pnpm/action-setup@v5
        with: { version: 11 }
-      - uses: actions/setup-node@v4
+      - uses: actions/setup-node@v5
        with: { node-version: 22, cache: pnpm }
      - run: pnpm install --frozen-lockfile
      - run: pnpm e2e
        env:
          HOME: /root
-      - uses: actions/upload-artifact@v4
+      - uses: actions/upload-artifact@v6
        if: failure()
        with:
          name: playwright-report
@@ -0,0 +1,125 @@
+name: Language smoke
+# Everyday code intelligence (completion, go to definition, Find Usages, hover, diagnostics
+# with a quick fix, an intention, formatting, rename) per language, against the language
+# server the app starts by default: crates/ide-host/tests/language_smoke.rs.
+# Opening the fixture with its build tool and SDK (Maven / Gradle sync, the virtualenv, the
+# JDK): the ignored tests of crates/ide-host/tests/project_smoke.rs.
+# Then running and testing each fixture through the run store and openidea-server
+# (Run, Run tests, the test tree, Rerun Failed Tests): smoke/run.test.ts; and debugging its
+# entry point with the debugger the IDE installs (breakpoint, frames, variables, evaluate,
+# Step Over, Resume): smoke/debug.test.ts.
+on:
+  push:
+    branches: [main]
+    paths: &paths
+      - "crates/**"
+      - "languages/**"
+      - "fixtures/**"
+      - "Cargo.toml"
+      - "Cargo.lock"
+      - "src/features/run/**"
+      - "src/features/debugger/**"
+      - "src/platform/**"
+      - "smoke/**"
+      - "package.json"
+      - "pnpm-lock.yaml"
+      - ".github/workflows/language-smoke.yml"
+  pull_request:
+    branches: [main]
+    types: [opened, synchronize, reopened]
+    paths: *paths
+  workflow_dispatch:
+
+concurrency:
+  group: language-smoke-${{ github.ref }}
+  # A new push supersedes a PR's run; on main every merge runs to the end (and saves the cache).
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
+
+env:
+  CARGO_TERM_COLOR: always
+  CARGO_INCREMENTAL: 0
+  # Pinned so a server release can't fail an unrelated PR; bump them deliberately.
+  VTSLS: 0.3.0
+  TYPESCRIPT: 6.0.3
+  BASEDPYRIGHT: 1.40.2
+  RUFF: 0.17.3
+  GOPLS: v0.24.0
+  JDTLS: 1.63.0-202610191322
+  KOTLIN_LSP: 263.7084.0
+  GRADLE: 8.14.3
+
+jobs:
+  smoke:
+    name: Language smoke (${{ matrix.language }})
+    strategy:
+      fail-fast: false
+      matrix:
+        language: [typescript, python, rust, go, java, kotlin]
+    runs-on: ubuntu-22.04
+    timeout-minutes: 40
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@stable
+        with: { components: "rust-analyzer, rustfmt" }
+      # One build cache for every language; main saves it.
+      - uses: Swatinem/rust-cache@v2
+        with:
+          shared-key: language-smoke
+          save-if: ${{ github.ref == 'refs/heads/main' && matrix.language == 'rust' }}
+
+      - uses: pnpm/action-setup@v4
+        with: { version: 11 }
+      - uses: actions/setup-node@v4
+        with: { node-version: 22, cache: pnpm }
+      - if: matrix.language == 'typescript'
+        run: npm install --global "@vtsls/language-server@$VTSLS" "typescript@$TYPESCRIPT"
+
+      - if: matrix.language == 'python'
+        uses: actions/setup-python@v5
+        with: { python-version: "3.12" }
+      - if: matrix.language == 'python'
+        run: pip install "basedpyright==$BASEDPYRIGHT" "ruff==$RUFF"
+
+      - if: matrix.language == 'go'
+        uses: actions/setup-go@v5
+        with: { go-version: "1.27", cache: false }
+      - if: matrix.language == 'go'
+        run: go install "golang.org/x/tools/gopls@$GOPLS"
+
+      - if: matrix.language == 'java' || matrix.language == 'kotlin'
+        uses: actions/setup-java@v4
+        with: { distribution: temurin, java-version: "21" }
+      - if: matrix.language == 'java'
+        run: |
+          mkdir -p "$RUNNER_TEMP/jdtls"
+          curl -fsSL "https://download.eclipse.org/jdtls/milestones/${JDTLS%-*}/jdt-language-server-$JDTLS.tar.gz" \
+            | tar xz -C "$RUNNER_TEMP/jdtls"
+          echo "$RUNNER_TEMP/jdtls/bin" >> "$GITHUB_PATH"
+
+      # The Kotlin fixture has no Gradle wrapper: the server imports it with the Gradle on PATH.
+      - if: matrix.language == 'kotlin'
+        uses: gradle/actions/setup-gradle@v4
+        with: { gradle-version: "${{ env.GRADLE }}" }
+      - if: matrix.language == 'kotlin'
+        run: |
+          mkdir -p "$RUNNER_TEMP/kotlin-lsp" "$RUNNER_TEMP/bin"
+          curl -fsSL "https://download.jetbrains.com/language-server/kotlin-server/$KOTLIN_LSP/kotlin-server-$KOTLIN_LSP.tar.gz" \
+            | tar xz -C "$RUNNER_TEMP/kotlin-lsp" --strip-components=1
+          ln -s "$RUNNER_TEMP/kotlin-lsp/kotlin-lsp.sh" "$RUNNER_TEMP/bin/kotlin-lsp"
+          echo "$RUNNER_TEMP/bin" >> "$GITHUB_PATH"
+
+      - run: cargo test --locked -p ide-host --test language_smoke --no-run
+      - run: cargo test --locked -p ide-host --test language_smoke -- --ignored --exact ${{ matrix.language }}
+      - if: matrix.language == 'java'
+        run: cargo test --locked -p ide-host --test project_smoke -- --ignored --exact maven_sync jdk
+      - if: matrix.language == 'kotlin'
+        run: cargo test --locked -p ide-host --test project_smoke -- --ignored --exact gradle_sync
+      - if: matrix.language == 'python'
+        run: cargo test --locked -p ide-host --test project_smoke -- --ignored --exact python_venv
+
+      - run: pnpm install --frozen-lockfile
+      - run: cargo build --locked -p ide-host --bin openidea-server
+      - run: pnpm smoke smoke/run.test.ts -t "^${{ matrix.language }}$"
+      - run: pnpm smoke smoke/debug.test.ts -t "^${{ matrix.language }}$"
+        # The IDE installs the debugger from GitHub releases: authenticated, against rate limits.
+        env: { GITHUB_TOKEN: "${{ github.token }}" }
@@ -0,0 +1,46 @@
+name: Plugin index
+
+# Refreshes the community plugins in the latest release's plugins-index.json
+# (what released apps read) from the registry, l0ng-ai/openidea-plugins. The
+# official plugins, their key and revocations stay as the release wrote them.
+on:
+  schedule:
+    - cron: "17 * * * *"
+  workflow_dispatch:
+  # Sent by the registry when its index changes.
+  repository_dispatch:
+    types: [community-plugins]
+
+permissions:
+  contents: write
+
+concurrency:
+  group: plugins-index
+
+env:
+  COMMUNITY_PLUGINS_INDEX: https://github.com/l0ng-ai/openidea-plugins/releases/download/index/index.json
+
+jobs:
+  merge:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Merge the community index
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          set -euo pipefail
+          cd "$RUNNER_TEMP"
+          tag="$(gh release view --repo "$GITHUB_REPOSITORY" --json tagName -q .tagName)"
+          tool=openidea-plugin-linux-x86_64
+          if ! gh release download "$tag" --repo "$GITHUB_REPOSITORY" -p plugins-index.json -p "$tool.gz"; then
+            echo "::notice::$tag has no plugin index or openidea-plugin tool yet"
+            exit 0
+          fi
+          gunzip "$tool.gz" && chmod +x "$tool"
+          cp plugins-index.json before.json
+          "./$tool" merge plugins-index.json "$COMMUNITY_PLUGINS_INDEX" --keep openidea
+          if cmp -s before.json plugins-index.json; then
+            echo "unchanged"
+          else
+            gh release upload "$tag" plugins-index.json --repo "$GITHUB_REPOSITORY" --clobber
+          fi
@@ -0,0 +1,60 @@
+name: PR check
+on:
+  # pull_request_target so the check can label PRs from forks. It never checks out
+  # or runs PR code: it only reads the PR title and description.
+  pull_request_target:
+    types: [opened, edited, reopened, ready_for_review]
+
+permissions:
+  issues: write
+  pull-requests: write
+
+concurrency:
+  group: pr-check-${{ github.event.pull_request.number }}
+  cancel-in-progress: true
+
+jobs:
+  check:
+    if: github.event.pull_request.user.type != 'Bot' && !github.event.pull_request.draft
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/github-script@v8
+        with:
+          script: |
+            const pr = context.payload.pull_request;
+            const LABEL = 'needs-info';
+            const MARKER = '<!-- pr-check -->';
+            const body = (pr.body || '').replace(/<!--[\s\S]*?-->/g, '');
+            const problems = [];
+
+            const verified = body.match(/^##+\s*How it was verified\s*$([\s\S]*?)(?=^##+\s|(?![\s\S]))/im);
+            if (!verified || !verified[1].trim()) {
+              problems.push('Fill in **How it was verified**: the commands you ran and their results. UI changes need before/after screenshots.');
+            }
+
+            const { owner, repo } = context.repo;
+            const issue_number = pr.number;
+            const comments = await github.paginate(github.rest.issues.listComments, { owner, repo, issue_number });
+            const existing = comments.find(c => c.user.type === 'Bot' && c.body.includes(MARKER));
+            const labeled = pr.labels.some(l => l.name === LABEL);
+
+            if (problems.length) {
+              const text = `${MARKER}\nThanks for the PR. Before review, please update the description (see [CONTRIBUTING.md](https://github.com/${owner}/${repo}/blob/main/CONTRIBUTING.md)):\n\n${problems.map(p => `- ${p}`).join('\n')}\n\nThis check reruns when you edit the description.`;
+              if (existing) {
+                await github.rest.issues.updateComment({ owner, repo, comment_id: existing.id, body: text });
+              } else {
+                await github.rest.issues.createComment({ owner, repo, issue_number, body: text });
+              }
+              if (!labeled) {
+                await github.rest.issues.addLabels({ owner, repo, issue_number, labels: [LABEL] });
+              }
+              return;
+            }
+
+            // Only undo what this check did: the label is cleared only when our comment exists.
+            if (existing) {
+              await github.rest.issues.deleteComment({ owner, repo, comment_id: existing.id });
+              if (labeled) {
+                await github.rest.issues.removeLabel({ owner, repo, issue_number, name: LABEL }).catch(() => {});
+              }
+            }
@@ -18,6 +18,7 @@ env:
  CARGO_TERM_COLOR: always
  CARGO_INCREMENTAL: 0
  TAG: ${{ github.event.inputs.tag || github.ref_name }}
+  COMMUNITY_PLUGINS_INDEX: https://github.com/l0ng-ai/openidea-plugins/releases/download/index/index.json

 jobs:
  # Creates (or reuses) one draft release that every platform build uploads into.
@@ -25,8 +26,9 @@ jobs:
    runs-on: ubuntu-latest
    outputs:
      release_id: ${{ steps.release.outputs.id }}
+      official_plugin_keys: ${{ steps.plugin-keys.outputs.keys }}
    steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
        with: { ref: "${{ env.TAG }}" }
      - name: Tag matches app version
        run: |
@@ -35,8 +37,32 @@ jobs:
            echo "::error::tag $TAG does not match tauri.conf.json version $app"
            exit 1
          fi
+      # A shipped plugin API is frozen: its WIT must be the snapshot api_frozen.rs checks later
+      # versions against (plugins/README.md, "Evolving the plugin API").
+      - name: Plugin API snapshot matches wit/
+        run: |
+          api() { sed -n 's/^package openidea:plugin@\(.*\);$/\1/p' "$1/plugin.wit"; }
+          snapshot=sdk/rust/openidea-plugin/tests/api/released
+          if [ "$(api wit)" != "$(api "$snapshot")" ]; then
+            echo "::error::plugin API $(api wit) ships without a snapshot ($snapshot is $(api "$snapshot")): copy wit/*.wit to $snapshot/"
+            exit 1
+          fi
+      # The official plugins' public key (from PLUGIN_SIGNING_KEY, the seed
+      # `openidea-plugin keygen` writes), built into the app: their packages
+      # must carry its signature whatever the marketplace index lists. Without
+      # the secret the app takes the index's word, as development builds do.
+      - id: plugin-keys
+        env:
+          SIGNING_KEY: ${{ secrets.PLUGIN_SIGNING_KEY }}
+        run: |
+          if [ -n "$SIGNING_KEY" ]; then
+            seed="$(printf %s "$SIGNING_KEY" | base64 -d | od -An -tx1 | tr -d ' \n')"
+            key="$(printf '302e020100300506032b657004220420%s' "$seed" | xxd -r -p |
+              openssl pkey -inform DER -pubout -outform DER | tail -c 32 | base64)"
+            echo "keys=$key" >> "$GITHUB_OUTPUT"
+          fi
      - id: release
-        uses: actions/github-script@v7
+        uses: actions/github-script@v8
        with:
          script: |
            const tag = process.env.TAG;
@@ -57,6 +83,8 @@ jobs:
  build:
    needs: create-release
    name: Build (${{ matrix.name }})
+    env:
+      OPENIDEA_OFFICIAL_PLUGIN_KEYS: ${{ needs.create-release.outputs.official_plugin_keys }}
    strategy:
      fail-fast: false
      matrix:
@@ -81,11 +109,11 @@ jobs:
            target: x86_64-pc-windows-msvc
    runs-on: ${{ matrix.os }}
    steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
        with: { ref: "${{ env.TAG }}" }
-      - uses: pnpm/action-setup@v4
+      - uses: pnpm/action-setup@v5
        with: { version: 11 }
-      - uses: actions/setup-node@v4
+      - uses: actions/setup-node@v5
        with: { node-version: 22, cache: pnpm }
      - uses: dtolnay/rust-toolchain@stable
        with: { targets: "${{ matrix.target }}" }
@@ -155,7 +183,7 @@ jobs:
          - { runner: macos-latest, target: x86_64-apple-darwin, os: macos, arch: x86_64 }
    runs-on: ${{ matrix.runner }}
    steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
        with: { ref: "${{ env.TAG }}" }
      - uses: dtolnay/rust-toolchain@stable
        with: { targets: "${{ matrix.target }}" }
@@ -180,13 +208,86 @@ jobs:
          if command -v sha256sum >/dev/null; then sha256sum "$ASSET"; else shasum -a 256 "$ASSET"; fi > "$ASSET.sha256"
          gh release upload "$TAG" "$ASSET" "$ASSET.sha256" --clobber

+  # The official plugins, signed, and the marketplace index released apps read
+  # (releases/latest/download/plugins-index.json). They are not in the
+  # installers: users install them from Settings › Plugins. Without the
+  # signing key (secret PLUGIN_SIGNING_KEY: the file `openidea-plugin keygen`
+  # writes) nothing is published and the release goes on. The index also lists
+  # the community plugins of the registry (COMMUNITY_PLUGINS_INDEX; refreshed
+  # between releases by plugins-index.yml), and the release carries the
+  # openidea-plugin tool for Linux x64, which that workflow and the registry's
+  # checks run.
+  plugins:
+    needs: create-release
+    name: Official plugins
+    runs-on: ubuntu-22.04
+    env:
+      SIGNING_KEY: ${{ secrets.PLUGIN_SIGNING_KEY }}
+    steps:
+      - id: key
+        run: |
+          if [ -z "$SIGNING_KEY" ]; then
+            echo "::warning::PLUGIN_SIGNING_KEY is not set: the official plugins are not published"
+            echo "skip=true" >> "$GITHUB_OUTPUT"
+          fi
+      - uses: actions/checkout@v5
+        if: steps.key.outputs.skip != 'true'
+        with: { ref: "${{ env.TAG }}" }
+      - uses: dtolnay/rust-toolchain@stable
+        if: steps.key.outputs.skip != 'true'
+        with: { targets: wasm32-wasip2 }
+      - uses: Swatinem/rust-cache@v2
+        if: steps.key.outputs.skip != 'true'
+        with: { key: release-plugins }
+      - uses: pnpm/action-setup@v5
+        if: steps.key.outputs.skip != 'true'
+        with: { version: 11 }
+      - uses: actions/setup-node@v5
+        if: steps.key.outputs.skip != 'true'
+        with: { node-version: 22 }
+      # Builds the web pages; fails when a checked-in component isn't built from these sources.
+      - name: Build
+        if: steps.key.outputs.skip != 'true'
+        run: |
+          plugins/build.sh --check
+          cargo build --release --locked -p ide-host --bin openidea-plugin
+      - name: Pack, index and upload
+        if: steps.key.outputs.skip != 'true'
+        shell: bash
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          set -euo pipefail
+          tool="$PWD/target/release/openidea-plugin"
+          key="$RUNNER_TEMP/openidea.key"
+          out="$RUNNER_TEMP/market"
+          (umask 077 && printf '%s' "$SIGNING_KEY" > "$key")
+          trap 'rm -f "$key"' EXIT
+          mkdir -p "$out"
+          for dir in plugins/official/*/; do
+            id="$(sed -n 's/^id *= *"\(.*\)".*/\1/p' "$dir/plugin.toml" | head -1)"
+            version="$(sed -n 's/^version *= *"\(.*\)".*/\1/p' "$dir/plugin.toml" | head -1)"
+            "$tool" pack "$dir" --key "$key" --publisher openidea --out "$out/$id-$version.oiplugin"
+          done
+          # The published index's revocations, earlier keys and community plugins carry over.
+          curl -fsSL "https://github.com/$GITHUB_REPOSITORY/releases/latest/download/plugins-index.json" \
+            -o "$out/plugins-index.json" || rm -f "$out/plugins-index.json"
+          # Downloads point at this release: older versions kept for older IDEs stay where they were published.
+          "$tool" index "$out" --publisher openidea --name OpenIDEA --key "$key" --out "$out/plugins-index.json" \
+            --download-base "https://github.com/$GITHUB_REPOSITORY/releases/download/$TAG"
+          "$tool" merge "$out/plugins-index.json" "$COMMUNITY_PLUGINS_INDEX" --keep openidea ||
+            echo "::warning::the community plugins were not refreshed"
+          gzip -9 -c "$tool" > "$out/openidea-plugin-linux-x86_64.gz"
+          gh release upload "$TAG" "$out"/*.oiplugin "$out/plugins-index.json" \
+            "$out/openidea-plugin-linux-x86_64.gz" --clobber
+
  # The updater manifest (latest.json), built once from the signed bundles every build uploaded.
  # Fails when a platform is missing, so a release never ships a manifest without it.
  updater-manifest:
    needs: [create-release, build]
    runs-on: ubuntu-latest
    steps:
-      - uses: actions/github-script@v7
+      - uses: actions/github-script@v8
        env:
          RELEASE_ID: ${{ needs.create-release.outputs.release_id }}
        with:
@@ -243,10 +344,10 @@ jobs:
            core.info(`latest.json: ${Object.keys(platforms).sort().join(", ")}`);

  publish:
-    needs: [create-release, build, server, updater-manifest]
+    needs: [create-release, build, server, plugins, updater-manifest]
    runs-on: ubuntu-latest
    steps:
-      - uses: actions/github-script@v7
+      - uses: actions/github-script@v8
        env:
          RELEASE_ID: ${{ needs.create-release.outputs.release_id }}
        with:
@@ -10,6 +10,9 @@ lerna-debug.log*
 node_modules
 dist
 dist-ssr
+# Plugin components are checked in (plugins/build.sh --check keeps them current).
+!plugins/official/*/dist
+!crates/ide-plugin/tests/fixtures/*/dist
 *.local

 # Editor directories and files
@@ -30,9 +33,13 @@ target/
 test-results/
 playwright-report/

-# Local AI agent files
-CLAUDE.md
-.claude/
+# Local AI agent files. Shared skills live in .agents/skills; .claude/skills links to them.
+CLAUDE.local.md
+.claude/*
+!.claude/skills/
+.claude/skills/*
+!.claude/skills/verify
+!.claude/skills/issue-fix

 # Local reference screenshots
 pycharm-screenshots/
@@ -10,10 +10,13 @@
    "target",
    "src/bindings.ts",
    "src/editor/core/cm/angular/parser*.ts",
+    "src/editor/core/cm/jsp/parser*.ts",
    "docs/plugins/themes.md",
    "pnpm-lock.yaml",
    "**/*.toml",
    "fixtures",
+    "plugins/*/web",
+    "plugins/official/*/web",
    "crates/**/tests/fixtures"
  ],
  "overrides": [
@@ -0,0 +1,130 @@
+# OpenIDEA — contributor guide
+
+Rust + Tauri 2 desktop IDE with full-featured, multi-language code intelligence.
+Visual style: dark, low-contrast greys, one cool accent
+(`src/styles/tokens.css` is the source of truth for colours and metrics).
+
+## Layout
+
+- `crates/ide-*` — backend crates; one domain each. Depend on `ide-core` for shared
+  types; never reach into another crate's internals.
+- `src-tauri/` — glue only: `state.rs` (AppState / Project), `commands/<domain>.rs`
+  (thin typed IPC adapters), `events.rs`. No domain logic here.
+- `src/bindings.ts` — generated by tauri-specta (`pnpm gen:bindings`). Never edit.
+- `src/platform/` — ipc (`call`, `onIdeEvent`, `nextRequestId`), actions registry,
+  keymap + dispatcher, context keys / `when` clauses, project store.
+- `src/workbench/contributions.ts` — extension points (tool windows, status items,
+  overlays, editor kinds) and cross-feature services (editor, tool windows, notifications).
+- `src/ui/` — design-system primitives. `src/features/<name>/` — one feature each,
+  exporting `activate()` registered in `src/features/index.ts`.
+- `languages/<id>.toml` — language definitions (detection, comments, LSP, DAP).
+- `crates/ide-host` — the `openidea-server` binary for remote development and the
+  `openidea-plugin` CLI (plugin starter templates live in its `templates.rs`).
+- `wit/` — plugin interface definitions; `plugins/` — sample and bundled plugins.
+  Plugin docs: `plugins/README.md`, `docs/plugins/themes.md`.
+- `java/` — JDT LS extension bundles (`java-usages`, `kotlin-bridge`) and the patched
+  Lombok agent, embedded into the app by `ide-sdk` / `ide-tools`.
+- `e2e/` — Playwright UI tests (`pnpm e2e`). `fixtures/` — sample projects per language
+  for manual and automated testing.
+
+## Rules
+
+- IPC coordinates: 0-based lines, **UTF-16** columns/offsets everywhere (`ide-core::text`).
+- Every command returns `IdeResult<T>`; convert internal errors at the crate edge.
+- Streaming → `tauri::ipc::Channel<T>`; cancellable → UI-allocated `RequestId` +
+  `cancel_request`. Backend → UI notifications → `IdeEvent` via `EventSink`.
+- Long work never blocks the UI thread or a Tauri command thread: use
+  `spawn_blocking`/rayon, honour `CancellationToken`.
+- Frontend features never import each other; communicate via actions, contributions
+  and services. All user-invocable behaviour is an action with a stable id; default
+  shortcuts live in `src/platform/keymaps/`.
+- Styling: CSS Modules + tokens only (no hex literals in components). Inline SVG
+  icons from `src/ui/icons.tsx`, never emoji. Real `<button>`/`<input>`; `aria-label` on icon buttons.
+- User-visible text goes through the text catalog: add every new string to both
+  `src/platform/locales/text/en.json` and `zh.json` (`textCatalog.test.ts` enforces it).
+  Other locales may lack entries; their UI shows the English text until a translator adds it.
+- Keep comments sparse and purposeful; match surrounding style.
+- For GUI verification, prefer Tauri MCP; use Computer Use only when Tauri MCP is
+  unavailable or cannot cover the required checks.
+
+## Issues & PRs
+
+Follow `CONTRIBUTING.md` and `.github/pull_request_template.md`: one problem per PR
+(`Closes #<n>` when it resolves an issue), reproduce first, keep the diff focused, short plain description, and a
+**How it was verified** section with commands run, results and, when the change alters what users
+see, before/after screenshots (not for UI removed along with a feature, copy-only or non-visual changes).
+Unclear product decisions → `needs-decision` and stop.
+
+## Skills
+
+Shared agent skills live in `.agents/skills/` (`.claude/skills/` links to them):
+`verify` drives the running app through Tauri MCP and captures screenshot evidence;
+`issue-fix` takes an issue from reproduction to one PR.
+
+## Commands
+
+- `pnpm tauri dev` — run the app with worktree isolation (Node 22.18+).
+  `pnpm dev:app` also enables the global Tauri API. `pnpm dev:status` reports
+  this worktree's running MCP bridges and actual ports.
+- `pnpm build` — typecheck + bundle frontend.
+- `cargo nextest run --workspace` (or `cargo test`), `cargo clippy --workspace --all-targets -- -D warnings`, `cargo fmt --all`.
+- `cargo test -p ide-host --test language_smoke -- --ignored --exact <language>` — code intelligence
+  on `fixtures/` with that language's real server installed (CI: `Language smoke`, pinned versions).
+- `pnpm smoke smoke/run.test.ts -t <language>` — run and test that language's fixture through the
+  run store and a real `openidea-server` (build it first: `cargo build -p ide-host --bin openidea-server`).
+- `pnpm smoke smoke/debug.test.ts -t <language>` — debug that fixture's entry point the same way, with
+  the debugger the IDE installs (on macOS, CodeLLDB and Delve may need Developer Mode:
+  `sudo DevToolsSecurity -enable`).
+- `pnpm test`, `pnpm e2e`, `pnpm lint`, `pnpm format:check`, `pnpm knip`, `pnpm typecheck`,
+  `pnpm gen:bindings`.
+- `pnpm perf` (UI interaction latency / frames / leaks), `pnpm perf:rust` (criterion
+  benches vs budgets). Budgets: `perf/budgets.json`.
+
+## Before opening a PR
+
+Run what CI runs for the parts you touched:
+
+- Rust: `cargo fmt --all --check`, `cargo clippy --workspace --all-targets -- -D warnings`,
+  `cargo nextest run --workspace`. After changing IPC types, run `pnpm gen:bindings` and
+  commit `src/bindings.ts`; CI fails if it differs.
+- Frontend: `pnpm typecheck`, `pnpm lint`, `pnpm format:check`, `pnpm knip`, `pnpm test`,
+  `pnpm build`, and `pnpm e2e` for UI flows.
+- UI or runtime behaviour: verify in the running app (`.agents/skills/verify`).
+
+## Pitfalls
+
+- Run a subset of frontend tests with `pnpm vitest run <path>`. `pnpm test -- <path>` ignores
+  the filter and runs the whole suite, which takes several minutes.
+- Don't run clippy while iterating: `pnpm tauri dev` compiles anyway. Run
+  `cargo fmt --all` + `cargo clippy -p <crate> --all-targets -- -D warnings` once, right
+  before committing. A cold build cache can take around 5 minutes. Run long checks one at
+  a time, not chained in one shell call that may hit the 10-minute tool timeout.
+- `pnpm tauri dev` does a full debug build. Clippy only checks the code, so a passing clippy
+  doesn't make the first launch fast.
+
+## Parallel worktrees
+
+Several worktrees can be developed and run side by side.
+
+- Create one per task: `git worktree add ../<name> -b <branch> origin/main`, then
+  `pnpm install` in it.
+- Launch with `pnpm tauri dev` / `pnpm dev:app`, not the raw `pnpm exec tauri dev` CLI. The
+  wrapper starts Vite on a worktree-derived port (advancing if occupied), passes its actual
+  URL to Tauri, and reports an existing launcher instead of starting another for the same
+  worktree. HMR uses the Vite port.
+- Debug app identity, data, settings, logs and single-instance scope follow the canonical
+  worktree path captured at build time, independent of launch cwd. Launching the same debug
+  binary again focuses its existing instance and forwards its path argument. Different
+  worktrees and the installed release can coexist. `--release` uses normal release identity
+  and bypasses the development wrapper.
+- MCP bridge ports are dynamic (9223–9322). Use `pnpm dev:status`, connect to the reported
+  port, verify identifier/cwd, and pass `appIdentifier: <port>` explicitly. Do not assume the
+  default MCP session belongs to this worktree.
+- Keep each worktree's Cargo output directory separate; do not point `CARGO_TARGET_DIR` or
+  `target` symlinks at a shared directory.
+- Each worktree's first build is cold (several minutes) and `cargo build` output takes
+  around 9 GB; tests, clippy and incremental builds add more. Avoid running several heavy builds on one machine at the same time.
+- Stop only processes started for the current worktree/session. Never use broad
+  process-name kills such as `pkill openidea`.
+- When done: stop that worktree's app and dev session, delete its build output, then
+  `git worktree remove ../<name>`.
@@ -0,0 +1 @@
+AGENTS.md
@@ -0,0 +1,39 @@
+# Contributing to OpenIDEA
+
+These rules apply to everyone, and to any coding agent working on their behalf.
+Project layout, coding rules, commands and checks are in [AGENTS.md](AGENTS.md).
+
+## Issues
+
+- One problem or request per issue. Use the issue forms.
+- Bugs: steps that reproduce the problem from a fresh start. A minimal sample
+  project is the fastest way to get a fix.
+- Features: state the problem and the acceptance criteria. A feature is ready to
+  build once a maintainer labels it `planned`.
+- Labels track status: `needs-info` waits on the reporter, `needs-decision` waits
+  on a maintainer, `planned` is accepted, `needs-acceptance` has a fix waiting to be
+  checked.
+
+## Pull requests
+
+- One problem per PR. If it resolves an issue, link it with `Closes #123`.
+- Reproduce the problem first, or write a test that fails before the fix.
+- Fix the cause, and check whether the same cause breaks anything nearby.
+- Keep the diff focused. Unrelated refactors go in their own PR.
+- Title: [Conventional Commits](https://www.conventionalcommits.org/), e.g.
+  `fix(editor): keep the caret visible after folding`.
+- Fill in the template. Keep the description short and in plain words. If it
+  doesn't fit in a few sentences, the PR is probably too big.
+- **How it was verified** is required: the commands you ran and their results,
+  and what else the change could affect. Changes to what users see need before/after
+  screenshots; multi-step interactions need a recording. UI that goes away with a removed
+  feature, copy-only and non-visual changes don't; say what you checked instead.
+- If a change needs a product decision you can't make, ask in the issue and stop
+  rather than guessing.
+
+Plugins: pull requests here add or change official plugins (`plugins/official/`)
+and the plugin API. Community plugins live in their authors' repositories and
+are listed through [l0ng-ai/openidea-plugins](https://github.com/l0ng-ai/openidea-plugins);
+see [`plugins/README.md`](plugins/README.md) § 8.1.
+
+A check on each PR adds `needs-info` when the verification section is missing, and removes it once it's filled in.
@@ -1,9 +1,11 @@
 [workspace]
 resolver = "3"
 members = ["crates/*", "src-tauri"]
+# Plugins and the guest SDK build for wasm32-wasip2 in their own workspaces.
+exclude = ["sdk", "plugins"]

 [workspace.package]
-version = "0.1.33"
+version = "0.1.37"
 edition = "2024"
 rust-version = "1.96"
 license = "Apache-2.0"
@@ -41,6 +43,8 @@ ide-ssh = { path = "crates/ide-ssh" }
 ide-remote = { path = "crates/ide-remote" }
 ide-host = { path = "crates/ide-host" }
 ide-notebook = { path = "crates/ide-notebook" }
+ide-extension = { path = "crates/ide-extension" }
+ide-plugin = { path = "crates/ide-plugin" }

 # serialization & IPC typing
 serde = { version = "1", features = ["derive"] }
@@ -69,9 +73,9 @@ ropey = "1.6"
 encoding_rs = "0.8"
 chardetng = "0.1"
 ignore = "0.4"
+base64 = "0.22"
 globset = "0.4"
 notify = "8"
-notify-debouncer-full = "0.6"
 trash = "5"
 blake3 = "1"
 dunce = "1"
@@ -81,6 +85,7 @@ zip = { version = "9", default-features = false, features = ["deflate"] }
 # search, index, language
 grep-searcher = "0.1"
 grep-regex = "0.1"
+regex-syntax = "0.8"
 grep-matcher = "0.1"
 nucleo-matcher = "0.3"
 redb = "4"
@@ -100,6 +105,9 @@ sqlx = { version = "0.9", default-features = false, features = ["runtime-tokio",
 tiberius = { version = "0.13", default-features = false, features = ["tds73", "rustls", "sql-browser-tokio"] }
 bb8 = "0.9"
 uuid = { version = "1", features = ["v4"] }
+# OS credential stores
+keyring = "4.2"
+keyring-core = "1"

 # testing
 insta = { version = "1", features = ["yaml"] }
@@ -109,8 +117,14 @@ tempfile = "3"
 [profile.dev]
 # Keep debug builds snappy while giving dependencies decent speed.
 opt-level = 0
+# Full debug info is most of target/. Line tables keep file:line in our backtraces, but a
+# debugger can't show locals; re-enable with `--config profile.dev.debug=true`.
+debug = "line-tables-only"
 [profile.dev.package."*"]
 opt-level = 2
+# Dependency frames keep function names only. Re-enable one with
+# `--config 'profile.dev.package.<crate>.debug=true'`.
+debug = false

 [profile.release]
 codegen-units = 1
@@ -14,7 +14,9 @@
  &nbsp;·&nbsp;
  <a href="#benchmark">Benchmark</a>
  &nbsp;·&nbsp;
-  <a href="https://discord.gg/2Zy4yn7gP">Discord</a>
+  <a href="#plugins">Plugins</a>
+  &nbsp;·&nbsp;
+  <a href="#community">Community</a>
 </p>

 https://github.com/user-attachments/assets/234dd54c-1255-4b3a-b35c-533d78d737c0
@@ -45,6 +47,23 @@ IDEA analyses Python more deeply, so "ready" doesn't mean the same work on
 both sides. Both are measured from the outside, the same way: see
 [`perf/compare`](perf/compare) to run it on your machine and projects.

+## Plugins
+
+Plugins add actions, completion, quick fixes, tool windows, custom editors,
+themes, file icons and languages. They run as sandboxed WebAssembly components;
+themes, icon themes and languages need no code at all.
+
+Install them from Settings › Plugins, or start your own with
+`openidea-plugin new` — see [Writing OpenIDEA plugins](plugins/README.md) and
+the [official plugins](plugins/official). The plugin API is still a preview.
+
+## Community
+
+- [Discord](https://discord.gg/2Zy4yn7gP) — questions, feedback and release news.
+- WeChat group — scan to join:
+
+  <img src="docs/assets/wechat-group.png" alt="WeChat group QR code" width="200">
+
 ## License

 [Apache 2.0](LICENSE). Bundled third-party assets are listed in [`THIRD_PARTY_LICENSES.md`](THIRD_PARTY_LICENSES.md).
@@ -2,11 +2,12 @@

 ## Project Lombok

-`plugins/lombok/lombok-1.18.48-openidea.1.jar` contains Project Lombok v1.18.48 with the Equinox
-classloader fix from [projectlombok/lombok#4059](https://github.com/projectlombok/lombok/pull/4059).
+`java/lombok/lombok-1.18.48-openidea.2.jar` contains Project Lombok v1.18.48 with the Equinox
+classloader fix from [projectlombok/lombok#4059](https://github.com/projectlombok/lombok/pull/4059)
+and the ECJ constructor-call fix from [projectlombok/lombok#4089](https://github.com/projectlombok/lombok/pull/4089).
 Copyright (C) 2009-2021 The Project Lombok Authors. MIT license and bundled component
-notices are retained in [plugins/lombok/LICENSE](plugins/lombok/LICENSE) and inside the jar.
-Source tag, patch commits and build instructions: [plugins/lombok/README.md](plugins/lombok/README.md).
+notices are retained in [java/lombok/LICENSE](java/lombok/LICENSE) and inside the jar.
+Source tag, patch commits and build instructions: [java/lombok/README.md](java/lombok/README.md).

 ## JetBrains IntelliJ Platform icons

@@ -51,6 +52,15 @@ Their original copyright headers and Apache-2.0 licensing are retained.

 At render time `src/ui/icons.tsx` may recolour monochrome icons to `currentColor`.

+## JetBrains IntelliJ Platform VCS log graph algorithms
+
+`crates/ide-vcs/src/bek.rs` and `src/features/vcs/graph.ts` adapt the Bek ordering,
+graph layout and LinearBek merge linearization algorithms from
+[intellij-community](https://github.com/JetBrains/intellij-community/tree/1d70d5c54302d655758edbd2f808fb8dea8b1764/platform/vcs-log/graph/src/com/intellij/vcs/log/graph)
+(`impl/facade/sort/bek`, `impl/permanent/GraphLayoutBuilder.kt` and
+`linearBek/LinearBekGraphBuilder.java`). Modified from the originals.
+Copyright 2000-2026 JetBrains s.r.o. and contributors. Apache License 2.0 (below).
+
 ## JetBrains IntelliJ Platform diff algorithm

 `src/features/vcs/comparison/**` is a TypeScript port of the text comparison of
@@ -64,6 +74,11 @@ from its tests (`LineComparisonUtilTest`, `WordComparisonUtilTest`,
 `SplitComparisonUtilTest`). Modified from the originals. Copyright 2000-2026
 JetBrains s.r.o. and contributors. Apache License 2.0 (below).

+`src/features/vcs/mergeDiff3.ts`, `chunkOptimizer.ts` and `mergeModel.ts` also adapt
+the IntelliJ Platform merge implementation (`MergeRangeUtil`, `MergeResolveUtil`,
+`ChunkOptimizer.LineChunkOptimizer` and `MergeConflictModel`). Modified from the
+originals. Copyright 2000-2026 JetBrains s.r.o. and contributors. Apache License 2.0 (below).
+
 `src/ui/openidea/**` holds OpenIDEA's own file-type icons drawn in the expui style for
 languages whose JetBrains icons are not open source (Go, Ruby, Dart, Lua, Zig,
 Svelte, …). Those using the page-with-corner-badge layout (`goMod`, `goWork`,
@@ -1,7 +1,9 @@
 //! Session settings (model, mode, thinking effort…), slash commands and context use, as
 //! the agent reports them over ACP.

-use crate::model::{AgentCommand, AgentConfigOption, AgentConfigValue, AgentConfigVia, AgentUsage};
+use crate::model::{
+    AgentCommand, AgentConfigOption, AgentConfigValue, AgentConfigVia, AgentCost, AgentLimit, AgentUsage,
+};
 use serde_json::{Value, json};

 /// Cursor exposes execution modes over ACP, but leaves approval policy to its client.
@@ -150,7 +152,27 @@ pub(crate) fn commands_of(update: &Value) -> Vec<AgentCommand> {
 /// `usage_update`: `{ used, size }`.
 pub(crate) fn usage_of(update: &Value) -> Option<AgentUsage> {
    let tokens = |key: &str| update.get(key)?.as_f64().map(|n| n.clamp(0.0, f64::from(u32::MAX)) as u32);
-    Some(AgentUsage { used: tokens("used")?, size: tokens("size").filter(|s| *s > 0)? })
+    let cost = update.get("cost").and_then(|c| {
+        Some(Box::new(AgentCost {
+            amount: c.get("amount")?.as_f64().filter(|a| a.is_finite() && *a >= 0.0)?,
+            currency: c.get("currency")?.as_str().filter(|c| !c.is_empty())?.to_owned(),
+        }))
+    });
+    Some(AgentUsage { used: tokens("used")?, size: tokens("size").filter(|s| *s > 0)?, cost })
+}
+
+/// The usage-limit windows a [`crate::LIMITS_UPDATE`] carries; malformed entries are skipped.
+pub(crate) fn limits_of(update: &Value) -> Vec<AgentLimit> {
+    let limits = update.get("limits").and_then(Value::as_array).into_iter().flatten();
+    limits
+        .filter_map(|l| {
+            Some(AgentLimit {
+                window: l.get("window")?.as_str().filter(|w| !w.is_empty())?.to_owned(),
+                used_percent: l.get("usedPercent")?.as_f64().filter(|p| p.is_finite())?.clamp(0.0, 100.0),
+                resets_ms: l.get("resetsMs").and_then(Value::as_f64),
+            })
+        })
+        .collect()
 }

 fn legacy(
@@ -29,7 +29,7 @@ use serde::{Deserialize, Serialize};
 use serde_json::{Value, json};
 use std::collections::{BTreeMap, BTreeSet, HashMap, HashSet, VecDeque};
 use std::path::{Path, PathBuf};
-use std::sync::atomic::{AtomicBool, AtomicU32, Ordering};
+use std::sync::atomic::{AtomicBool, AtomicU32, AtomicU64, Ordering};
 use std::sync::{Arc, Weak};
 use std::time::Duration;

@@ -44,15 +44,22 @@ const REPLAY_GRACE: Duration = Duration::from_millis(300);
 /// can trail its `session/prompt` response by this much.
 const TURN_GRACE: Duration = Duration::from_millis(100);
 const STDERR_LINES: usize = 20;
+/// An agent idle this long after its turn is stopped when it can reload its session
+/// (`session/load`): the next message starts it again where it left off.
+const IDLE_RELEASE: Duration = Duration::from_secs(5 * 60);
 /// Updates of a session's state rather than its conversation.
 const SESSION_STATE: [&str; 5] =
    ["session_info_update", "config_option_update", "current_mode_update", "available_commands_update", "usage_update"];
 /// A native agent's own update: it is about to retry a failed API request (see [`AgentRetry`]).
 pub(crate) const RETRY_UPDATE: &str = "openidea_retry";
+/// A native agent's own update: the usage limits of its account (see [`AgentLimit`]).
+pub(crate) const LIMITS_UPDATE: &str = "openidea_limits";
 /// Referenced files up to this size are embedded in the prompt (when the agent takes it).
 const MAX_EMBED: u64 = 256 * 1024;
 /// How long a probe waits for the agent to answer `initialize`.
 const PROBE_TIMEOUT: Duration = Duration::from_secs(30);
+/// How long deleting a task waits for its agent to exit before removing the worktree.
+const EXIT_WAIT: Duration = Duration::from_secs(5);

 /// The agent tasks of one project.
 pub struct AgentManager {
@@ -90,6 +97,8 @@ struct Shared {
    providers: RwLock<Vec<provider::ProviderSpec>>,
    /// Last probe of each provider.
    probes: Mutex<HashMap<String, AgentProbe>>,
+    /// [`IDLE_RELEASE`], in milliseconds (shorter in tests).
+    idle_release_ms: AtomicU64,
 }

 /// What an agent offered in its last session, for the New Task page.
@@ -205,6 +214,8 @@ struct Live {
    capabilities: AgentCapabilities,
    /// `promptCapabilities.embeddedContext`: referenced files are sent with their text.
    embedded: bool,
+    /// `session/load`: the process can be stopped between turns and the session reloaded.
+    resumable: bool,
 }

 struct Task {
@@ -226,6 +237,8 @@ struct Task {
    cancel_pending: AtomicBool,
    /// The agent reported something for the current turn.
    turn_started: AtomicBool,
+    /// Turns sent so far: an idle release scheduled before the latest one is void.
+    turns: AtomicU64,
    /// Settings already sent this session (`(option, value)`), so a refusal is not retried.
    config_sent: Mutex<HashSet<(String, String)>>,
    dirty: Mutex<BTreeSet<(Session, usize)>>,
@@ -236,6 +249,11 @@ struct Task {
 }

 impl AgentManager {
+    #[cfg(test)]
+    fn set_idle_release(&self, delay: Duration) {
+        self.shared.idle_release_ms.store(delay.as_millis() as u64, Ordering::Relaxed);
+    }
+
    /// Loads the project's saved tasks. Spawned work runs on `runtime`.
    pub fn new(paths: AgentPaths, runtime: tokio::runtime::Handle) -> Self {
        let connector: Connector = Arc::new(|spec, cwd, client, on_stderr| match spec.driver {
@@ -260,6 +278,7 @@ impl AgentManager {
            known: Mutex::new(known),
            providers,
            probes: Mutex::new(HashMap::new()),
+            idle_release_ms: AtomicU64::new(IDLE_RELEASE.as_millis() as u64),
        });
        let mut tasks = HashMap::new();
        for file in std::fs::read_dir(&shared.paths.store_dir).into_iter().flatten().flatten() {
@@ -301,23 +320,49 @@ impl AgentManager {
        let specs = provider::load(self.shared.paths.custom_agents_dir.as_deref());
        let list = specs
            .iter()
-            .map(|p| AgentProvider {
-                id: p.id.clone(),
-                name: p.name.clone(),
-                command: std::iter::once(p.command.as_str())
-                    .chain(p.args.iter().map(String::as_str))
-                    .collect::<Vec<_>>()
-                    .join(" "),
-                installed: provider::installed(&p.command),
-                config: self.shared.known_config(&p.id),
-                commands: self.shared.known_commands(&p.id),
-                source: p.source.clone(),
+            .map(|p| {
+                let mut info = provider::describe(p);
+                info.config = self.shared.known_config(&p.id);
+                info.commands = self.shared.known_commands(&p.id);
+                info
            })
            .collect();
-        *self.shared.providers.write() = specs;
+        let mut prev = self.shared.providers.write();
+        let mut probes = self.shared.probes.lock();
+        probes.retain(|id, _| {
+            let old = prev.iter().find(|p| &p.id == id);
+            let new = specs.iter().find(|p| &p.id == id);
+            matches!((old, new), (Some(a), Some(b)) if a.command == b.command && a.args == b.args && a.env == b.env)
+        });
+        *prev = specs;
        list
    }

+    /// Overrides built-in `id`'s command with `command` (the driver and arguments stay
+    /// the built-in's) through its agent file, or returns it to auto-detection with `None`.
+    pub fn set_builtin_command(&self, id: &str, command: Option<String>) -> IdeResult<()> {
+        let Some(dir) = self.shared.paths.custom_agents_dir.clone() else {
+            return Err(IdeError::unavailable("there is no custom agents directory"));
+        };
+        provider::set_builtin_command(&dir, id, command.as_deref())
+    }
+
+    /// Sets the environment variables built-in `id` starts with; empty clears them.
+    pub fn set_builtin_env(&self, id: &str, env: std::collections::BTreeMap<String, String>) -> IdeResult<()> {
+        let Some(dir) = self.shared.paths.custom_agents_dir.clone() else {
+            return Err(IdeError::unavailable("there is no custom agents directory"));
+        };
+        provider::set_builtin_env(&dir, id, env)
+    }
+
+    /// Re-reads configured/installed agents, drops cached probes, and notifies subscribers.
+    pub fn reload_providers(&self) {
+        let specs = provider::load(self.shared.paths.custom_agents_dir.as_deref());
+        *self.shared.providers.write() = specs;
+        self.shared.probes.lock().clear();
+        self.shared.emit(AgentEvent::Providers);
+    }
+
    /// The slash commands to complete for `provider`, in `task`'s directory or (without one)
    /// in the project: what the agent offered last time there, unadvertised builtins,
    /// and, for Claude Code, skills and custom commands on disk it has not listed.
@@ -796,7 +841,7 @@ impl AgentManager {
    /// Forgets the task; with `remove_worktree` also deletes its worktree (the branch stays).
    pub async fn delete(&self, id: &str, remove_worktree: bool) -> IdeResult<()> {
        let task = self.task(id)?;
-        task.kill();
+        let live = task.kill();
        let (isolation, cwd, root) = {
            let s = task.state.lock();
            (
@@ -808,7 +853,13 @@ impl AgentManager {
        // A copy of the task (a fork) may work in the same worktree.
        let shared = self.tasks.read().values().any(|t| t.id != id && t.state.lock().task.cwd.0 == cwd);
        if remove_worktree && !shared && isolation == Isolation::Worktree && cwd.exists() {
-            blocking(move || worktree::remove(&root, &cwd)).await?;
+            // On Windows the agent's processes lock the folder (their working directory,
+            // open files) until they have exited.
+            if let Some(peer) = live {
+                let _ = tokio::time::timeout(EXIT_WAIT, peer.exited()).await;
+            }
+            let worktrees = self.shared.paths.worktrees_dir.clone();
+            blocking(move || worktree::remove(&root, &worktrees, &cwd)).await?;
        }
        self.tasks.write().remove(id);
        *task.deleted.lock() = true;
@@ -867,6 +918,7 @@ impl Task {
            send_now: AtomicBool::new(false),
            cancel_pending: AtomicBool::new(false),
            turn_started: AtomicBool::new(false),
+            turns: AtomicU64::new(0),
            config_sent: Mutex::new(HashSet::new()),
            dirty: Mutex::new(BTreeSet::new()),
            flush_scheduled: AtomicBool::new(false),
@@ -1009,12 +1061,42 @@ impl Task {
            }
            match (next, result) {
                (Some(queued), _) => prompt = queued.prompt,
-                (None, Ok(_)) => return self.set_status(AgentStatus::Ready, None),
+                (None, Ok(_)) => {
+                    self.set_status(AgentStatus::Ready, None);
+                    return self.release_when_idle();
+                }
                (None, Err(failure)) => return self.fail(failure),
            }
        }
    }

+    /// Stops the agent's process once the task has stayed idle for [`IDLE_RELEASE`], so
+    /// finished tasks don't keep an agent (and what it started) running. Only an agent that
+    /// reloads its session: the next message starts it again with the conversation intact.
+    fn release_when_idle(self: &Arc<Self>) {
+        let turn = self.turns.load(Ordering::Acquire);
+        let delay = Duration::from_millis(self.shared.idle_release_ms.load(Ordering::Relaxed));
+        let task = Arc::downgrade(self);
+        self.shared.runtime.spawn(async move {
+            tokio::time::sleep(delay).await;
+            let Some(task) = task.upgrade() else { return };
+            if task.turns.load(Ordering::Acquire) != turn
+                || task.state.lock().busy
+                || !task.permissions.lock().is_empty()
+            {
+                return;
+            }
+            let live = {
+                let mut live = task.live.lock();
+                if live.as_ref().is_some_and(|l| l.resumable && !l.peer.is_closed()) { live.take() } else { None }
+            };
+            if let Some(live) = live {
+                tracing::debug!("agent task {}: idle, stopping the agent until the next message", task.id);
+                live.peer.kill();
+            }
+        });
+    }
+
    /// Ends a turn that failed: nothing it started stays open.
    fn fail(self: &Arc<Self>, failure: Failure) {
        self.cancel_permissions();
@@ -1075,6 +1157,7 @@ impl Task {

    /// Sends one prompt, starting the agent first if needed; returns the stop reason.
    async fn turn(self: &Arc<Self>, prompt: &AgentPrompt) -> Result<String, Failure> {
+        self.turns.fetch_add(1, Ordering::AcqRel);
        self.turn_started.store(false, Ordering::Release);
        self.state.lock().task.resets_ms = None;
        let attachments = prompt
@@ -1271,7 +1354,7 @@ impl Task {
        }
        self.persist();
        self.emit_task();
-        let live = Live { peer, session: session_id, capabilities, embedded };
+        let live = Live { peer, session: session_id, capabilities, embedded, resumable: can_load };
        *self.live.lock() = Some(live.clone());
        Ok(live)
    }
@@ -1353,6 +1436,13 @@ impl Task {
            }
            return;
        }
+        if kind == LIMITS_UPDATE {
+            if !self.replaying.load(Ordering::Acquire) {
+                let provider = self.state.lock().task.provider.clone();
+                self.shared.emit(AgentEvent::Limits { provider, limits: config::limits_of(update) });
+            }
+            return;
+        }
        if kind == "session_info_update" {
            // The agent's own title for the session replaces the first line of the prompt.
            let title = update.get("title").and_then(Value::as_str).map(str::trim).filter(|t| !t.is_empty());
@@ -1522,11 +1612,12 @@ impl Task {
        }
    }

-    fn kill(&self) {
+    /// Stops the agent; returns its connection, to wait for its process to exit.
+    fn kill(&self) -> Option<acp::Conn> {
        self.cancel_permissions();
-        if let Some(live) = self.live.lock().take() {
-            live.peer.kill();
-        }
+        let live = self.live.lock().take()?;
+        live.peer.kill();
+        Some(live.peer)
    }
 }

@@ -3,6 +3,7 @@
 use ide_core::IpcPath;
 use serde::{Deserialize, Serialize};
 use specta::Type;
+use std::collections::BTreeMap;

 #[derive(Clone, Copy, Debug, PartialEq, Eq, Serialize, Deserialize, Type)]
 #[serde(rename_all = "camelCase")]
@@ -154,6 +155,30 @@ pub struct AgentUsage {
    pub used: u32,
    /// Size of the context window.
    pub size: u32,
+    /// What the session has cost so far (ACP `usage_update.cost`), when the agent reports it.
+    // Boxed so that `AgentEvent::Task` stays within clippy's `large_enum_variant` bound on Windows.
+    #[serde(default)]
+    pub cost: Option<Box<AgentCost>>,
+}
+
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize, Type)]
+#[serde(rename_all = "camelCase")]
+pub struct AgentCost {
+    pub amount: f64,
+    /// ISO 4217 code, e.g. `USD`.
+    pub currency: String,
+}
+
+/// One usage-limit window of an agent's account.
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize, Type)]
+#[serde(rename_all = "camelCase")]
+pub struct AgentLimit {
+    /// The window as the agent names it: `five_hour`, `seven_day`, `seven_day_opus`…
+    pub window: String,
+    /// Share of the window used, 0–100.
+    pub used_percent: f64,
+    /// When the window resets (ms since the epoch), if the agent said.
+    pub resets_ms: Option<f64>,
 }

 #[derive(Clone, Debug, PartialEq, Serialize, Deserialize, Type)]
@@ -322,8 +347,19 @@ pub struct AgentProvider {
    pub name: String,
    /// The command line that starts its ACP server.
    pub command: String,
+    /// Executable and arguments actually launched, without flattening paths containing spaces.
+    pub program: String,
+    pub args: Vec<String>,
+    pub default_program: Option<String>,
+    pub default_args: Vec<String>,
+    pub login_hint: Option<String>,
+    pub command_overridden: bool,
+    pub command_editable: bool,
+    pub command_read_only_reason: Option<AgentCommandReadOnlyReason>,
    /// Whether the command was found (on `PATH`).
    pub installed: bool,
+    /// Environment variables it starts with (from its agent file).
+    pub env: BTreeMap<String, String>,
    /// Settings (models, modes…) the agent offered last time it ran; empty before its first session.
    pub config: Vec<AgentConfigOption>,
    /// Slash commands it offered last time.
@@ -331,6 +367,15 @@ pub struct AgentProvider {
    pub source: AgentSource,
 }

+/// Why the executable cannot be changed in built-in agent settings.
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize, Type)]
+#[serde(rename_all = "camelCase")]
+pub enum AgentCommandReadOnlyReason {
+    PackageRunner,
+    Registry,
+    CustomAgent,
+}
+
 /// Where an agent comes from.
 #[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize, Type)]
 #[serde(tag = "kind", rename_all = "camelCase")]
@@ -413,4 +458,11 @@ pub enum AgentEvent {
        index: u32,
        entry: AgentEntry,
    },
+    /// An agent reported the usage limits of its account (shared by every task of `provider`).
+    Limits {
+        provider: String,
+        limits: Vec<AgentLimit>,
+    },
+    /// The installed or configured agent providers changed.
+    Providers,
 }
@@ -98,6 +98,8 @@ impl Cli for Process {
        use std::process::Stdio;
        let mut cmd = tokio::process::Command::new(&l.program);
        ide_core::process::prepare(cmd.as_std_mut());
+        // `claude` may be a wrapper (`claude.cmd` → node): stopping it stops what it started.
+        ide_core::process::own_group(cmd.as_std_mut());
        cmd.args(&l.args)
            .current_dir(&l.cwd)
            .envs(ide_core::process::shell_env())
@@ -120,6 +122,9 @@ impl Cli for Process {
            tokio::select! {
                _ = child.wait() => {}
                _ = token.cancelled() => {
+                    if let Some(pid) = child.id() {
+                        let _ = tokio::task::spawn_blocking(move || ide_core::process::kill_tree_of(pid)).await;
+                    }
                    let _ = child.start_kill();
                    let _ = child.wait().await;
                }
@@ -904,6 +904,7 @@ impl Session {
                    if info.get("status").and_then(Value::as_str) == Some("rejected") {
                        st.limit_resets_ms = info.get("resetsAt").and_then(Value::as_f64).map(|s| s * 1000.0);
                    }
+                    updates.extend(st.tr.on_rate_limit(&info));
                }
                "command_lifecycle" => {
                    let uuid = msg.get("command_uuid").and_then(Value::as_str);
@@ -1013,6 +1013,39 @@ fn streamed_text_is_not_sent_twice() {
    assert_eq!(usage[0].update, json!({"sessionUpdate": "usage_update", "used": 15, "size": 1000}));
 }

+#[test]
+fn rate_limits_and_cost() {
+    let mut t = Translator::new("s", PathBuf::from("/w"), false);
+    let info = json!({"status": "allowed", "rateLimitType": "five_hour", "unifiedWindows": {
+        "five_hour": {"utilization": 0.19, "resetsAt": 100, "status": "allowed"},
+        "seven_day": {"utilization": 0.09, "resetsAt": 200, "status": "allowed"},
+    }});
+    let limits = t.on_rate_limit(&info).unwrap();
+    assert_eq!(limits.session, "s");
+    assert_eq!(limits.update["sessionUpdate"], crate::LIMITS_UPDATE);
+    let windows: Vec<(&str, i64, f64)> = limits.update["limits"]
+        .as_array()
+        .unwrap()
+        .iter()
+        .map(|l| {
+            (
+                l["window"].as_str().unwrap(),
+                l["usedPercent"].as_f64().unwrap().round() as i64,
+                l["resetsMs"].as_f64().unwrap(),
+            )
+        })
+        .collect();
+    assert_eq!(windows, [("five_hour", 19, 100_000.0), ("seven_day", 9, 200_000.0)]);
+    // Older versions report the window that applies, alone.
+    let single = t.on_rate_limit(&json!({"rateLimitType": "seven_day", "utilization": 0.5})).unwrap();
+    assert_eq!(single.update["limits"], json!([{"window": "seven_day", "usedPercent": 50.0, "resetsMs": null}]));
+    assert_eq!(t.on_rate_limit(&json!({"status": "allowed", "resetsAt": 100})), None, "no utilization, no update");
+
+    t.used = Some(10);
+    let usage = t.on_result(&json!({"total_cost_usd": 0.5, "modelUsage": {"x": {"contextWindow": 1000}}}));
+    assert_eq!(usage[0].update["cost"], json!({"amount": 0.5, "currency": "USD"}));
+}
+
 #[test]
 fn tool_calls_plans_and_subagents() {
    let mut t = Translator::new("s", PathBuf::from("/w"), true);
@@ -5,7 +5,7 @@
 //! Agent tool use that launched them: their messages carry it as `parent_tool_use_id`.

 use super::tools;
-use crate::RETRY_UPDATE;
+use crate::{LIMITS_UPDATE, RETRY_UPDATE};
 use serde_json::{Value, json};
 use std::collections::{HashMap, VecDeque};
 use std::path::PathBuf;
@@ -58,6 +58,8 @@ pub(super) struct Translator {
    pub used: Option<u64>,
    pub model: Option<String>,
    windows: HashMap<String, u64>,
+    /// The session's cost so far in USD, as the last `result` reported it.
+    cost_usd: Option<f64>,
 }

 impl Translator {
@@ -75,6 +77,7 @@ impl Translator {
            used: None,
            model: None,
            windows: HashMap::new(),
+            cost_usd: None,
        }
    }

@@ -169,7 +172,7 @@ impl Translator {
                    Some("tool_use") => {
                        // The input streams after this: shown by name until the message has it.
                        let (id, name) = (str_of(&block, "id"), str_of(&block, "name"));
-                        if !id.is_empty() && !tools::is_plan(&name) && !(tools::is_agent(&name) && self.subagents) {
+                        if !(id.is_empty() || tools::is_plan(&name) || tools::is_agent(&name) && self.subagents) {
                            out.extend(self.ensure_call(&id, &name, &json!({}), &session));
                        }
                    }
@@ -543,6 +546,9 @@ impl Translator {
                self.windows.insert(model.clone(), w);
            }
        }
+        if let Some(cost) = result.get("total_cost_usd").and_then(Value::as_f64).filter(|c| c.is_finite()) {
+            self.cost_usd = Some(cost);
+        }
        self.usage_update().into_iter().collect()
    }

@@ -557,9 +563,33 @@ impl Translator {
                    .or_else(|| self.windows.iter().find(|(k, _)| k.starts_with(m.as_str())).map(|(_, v)| v))
            })
            .or_else(|| (self.windows.len() == 1).then(|| self.windows.values().next()).flatten())?;
-        Some(Update {
+        let mut update = json!({ "sessionUpdate": "usage_update", "used": used, "size": size });
+        if let Some(amount) = self.cost_usd {
+            update["cost"] = json!({ "amount": amount, "currency": "USD" });
+        }
+        Some(Update { session: self.root.clone(), update })
+    }
+
+    /// The usage-limit windows a `rate_limit_event` reports, as a [`LIMITS_UPDATE`]: every
+    /// window of `unifiedWindows`, or the single `rateLimitType` window older versions send.
+    pub fn on_rate_limit(&self, info: &Value) -> Option<Update> {
+        let window = |name: &str, w: &Value| {
+            let utilization = w.get("utilization")?.as_f64()?;
+            Some(json!({
+                "window": name,
+                "usedPercent": utilization * 100.0,
+                "resetsMs": w.get("resetsAt").and_then(Value::as_f64).map(|s| s * 1000.0),
+            }))
+        };
+        let limits: Vec<Value> = match info.get("unifiedWindows").and_then(Value::as_object) {
+            Some(windows) => windows.iter().filter_map(|(name, w)| window(name, w)).collect(),
+            None => {
+                info.get("rateLimitType").and_then(Value::as_str).and_then(|t| window(t, info)).into_iter().collect()
+            }
+        };
+        (!limits.is_empty()).then(|| Update {
            session: self.root.clone(),
-            update: json!({ "sessionUpdate": "usage_update", "used": used, "size": size }),
+            update: json!({ "sessionUpdate": LIMITS_UPDATE, "limits": limits }),
        })
    }
 }
@@ -2,7 +2,8 @@
 //! `<config>/agents/<id>.toml` (written by hand, or by installing one from the ACP
 //! Registry, see `registry`).

-use crate::AgentSource;
+use crate::{AgentCommandReadOnlyReason, AgentProvider, AgentSource};
+use ide_core::{IdeError, IdeResult};
 use serde::{Deserialize, Serialize};
 use std::collections::BTreeMap;
 use std::path::{Path, PathBuf};
@@ -80,9 +81,103 @@ fn builtins() -> Vec<ProviderSpec> {
        .collect()
 }

-/// Whether `id` names a built-in agent.
+/// Whether `id` names a built-in agent that needs no registry install (native drivers
+/// and `npx -y` adapters). CLI built-ins (`copilot`, `gemini`, …) can be installed and
+/// updated from the ACP Registry into `<config>/agents/<id>.toml`.
 pub(crate) fn is_builtin(id: &str) -> bool {
-    BUILTIN.iter().any(|b| b.0 == id)
+    BUILTIN.iter().any(|&(bid, _, driver, cmd, _)| bid == id && (driver != Driver::Acp || cmd.first() == Some(&"npx")))
+}
+
+/// Display name of a built-in agent, when `id` is one.
+pub(crate) fn builtin_name(id: &str) -> Option<&'static str> {
+    BUILTIN.iter().find(|&&(bid, _, _, _, _)| bid == id).map(|&(_, name, _, _, _)| name)
+}
+
+/// The built-in spec of `id`.
+pub(crate) fn builtin_spec(id: &str) -> Option<ProviderSpec> {
+    builtins().into_iter().find(|s| s.id == id)
+}
+
+/// Public launch metadata, keeping the built-in defaults separate from agent-file overrides.
+pub(crate) fn describe(spec: &ProviderSpec) -> AgentProvider {
+    let builtin = builtin_spec(&spec.id);
+    let reason = if matches!(spec.source, AgentSource::Registry { .. }) {
+        Some(AgentCommandReadOnlyReason::Registry)
+    } else if let Some(default) = &builtin {
+        matches!(default.command.as_str(), "npx" | "bunx" | "uvx").then_some(AgentCommandReadOnlyReason::PackageRunner)
+    } else {
+        Some(AgentCommandReadOnlyReason::CustomAgent)
+    };
+    AgentProvider {
+        id: spec.id.clone(),
+        name: spec.name.clone(),
+        command: std::iter::once(spec.command.as_str())
+            .chain(spec.args.iter().map(String::as_str))
+            .collect::<Vec<_>>()
+            .join(" "),
+        program: spec.command.clone(),
+        args: spec.args.clone(),
+        default_program: builtin.as_ref().map(|b| b.command.clone()),
+        default_args: builtin.as_ref().map(|b| b.args.clone()).unwrap_or_default(),
+        login_hint: Some(spec.login_hint.clone()),
+        command_overridden: builtin.as_ref().is_some_and(|b| b.command != spec.command),
+        command_editable: reason.is_none(),
+        command_read_only_reason: reason,
+        installed: installed(&spec.command),
+        env: spec.env.iter().cloned().collect(),
+        config: vec![],
+        commands: vec![],
+        source: spec.source.clone(),
+    }
+}
+
+/// Overrides built-in `id`'s command through its agent file, preserving other
+/// customizations. `None` restores the built-in command and removes a redundant file.
+pub(crate) fn set_builtin_command(custom_dir: &Path, id: &str, command: Option<&str>) -> IdeResult<()> {
+    update_builtin(custom_dir, id, |agent, builtin| agent.command = command.unwrap_or(&builtin.command).to_owned())
+}
+
+/// The environment built-in `id` starts with, through its agent file (empty clears it).
+pub(crate) fn set_builtin_env(custom_dir: &Path, id: &str, env: BTreeMap<String, String>) -> IdeResult<()> {
+    update_builtin(custom_dir, id, |agent, _| agent.env = env)
+}
+
+/// Changes built-in `id`'s agent file; a file left with only the built-in's values is removed.
+fn update_builtin(custom_dir: &Path, id: &str, change: impl FnOnce(&mut CustomAgent, &ProviderSpec)) -> IdeResult<()> {
+    let Some(builtin) = builtin_spec(id) else {
+        return Err(IdeError::invalid(format!("{id} is not a built-in agent")));
+    };
+    let file = custom_dir.join(format!("{id}.toml"));
+    let mut agent = if file.try_exists()? {
+        CustomAgent::read(&file).map_err(IdeError::invalid)?
+    } else {
+        CustomAgent {
+            name: Some(builtin.name.clone()),
+            driver: builtin.driver,
+            command: builtin.command.clone(),
+            args: builtin.args.clone(),
+            env: BTreeMap::new(),
+            registry: None,
+        }
+    };
+    if agent.registry.is_some() {
+        return Err(IdeError::invalid(format!("{id} is installed from the ACP Registry")));
+    }
+    change(&mut agent, &builtin);
+    if agent.command == builtin.command
+        && agent.name.as_deref() == Some(builtin.name.as_str())
+        && agent.driver == builtin.driver
+        && agent.args == builtin.args
+        && agent.env.is_empty()
+    {
+        match std::fs::remove_file(&file) {
+            Err(e) if e.kind() != std::io::ErrorKind::NotFound => return Err(e.into()),
+            _ => {}
+        }
+        return Ok(());
+    }
+    agent.write(&file)?;
+    Ok(())
 }

 /// An agent file, `<config>/agents/<id>.toml`.
@@ -162,7 +257,7 @@ pub(crate) fn load(custom_dir: Option<&Path>) -> Vec<ProviderSpec> {
            Some(r) => AgentSource::Registry { version: r.version, update: None },
            None => AgentSource::Custom,
        };
-        let spec = ProviderSpec {
+        let mut spec = ProviderSpec {
            name: agent.name.unwrap_or_else(|| id.clone()),
            driver: agent.driver,
            command: agent.command,
@@ -173,7 +268,13 @@ pub(crate) fn load(custom_dir: Option<&Path>) -> Vec<ProviderSpec> {
            id,
        };
        match specs.iter_mut().find(|s| s.id == spec.id) {
-            Some(existing) => *existing = spec,
+            Some(existing) => {
+                spec.login_hint = existing.login_hint.clone();
+                if spec.source == AgentSource::Custom {
+                    spec.source = AgentSource::Builtin;
+                }
+                *existing = spec;
+            }
            None => specs.push(spec),
        }
    }
@@ -211,6 +312,54 @@ fn is_executable(p: &Path) -> bool {
 mod tests {
    use super::*;

+    #[test]
+    fn launch_metadata_distinguishes_defaults_overrides_and_read_only_agents() {
+        let dir = tempfile::tempdir().unwrap();
+        let list = || load(Some(dir.path())).iter().map(describe).collect::<Vec<_>>();
+        let defaults = list();
+        let codex = defaults.iter().find(|p| p.id == "codex").unwrap();
+        assert_eq!(codex.program, "codex");
+        assert_eq!(codex.default_program.as_deref(), Some("codex"));
+        assert_eq!(codex.args, ["app-server"]);
+        assert_eq!(codex.default_args, codex.args);
+        assert_eq!(codex.command, "codex app-server");
+        assert_eq!(codex.login_hint.as_deref(), Some("Run `codex login` in a terminal."));
+        assert!(!codex.command_overridden);
+        assert!(codex.command_editable);
+        for p in &defaults {
+            assert_eq!(p.source, AgentSource::Builtin);
+            assert!(p.default_program.is_some());
+            assert_eq!(p.command_editable, !p.id.ends_with("-acp"));
+            assert_eq!(
+                p.command_read_only_reason,
+                p.id.ends_with("-acp").then_some(AgentCommandReadOnlyReason::PackageRunner)
+            );
+        }
+        set_builtin_command(dir.path(), "codex", Some("/path with spaces/codex")).unwrap();
+        let overridden = list().into_iter().find(|p| p.id == "codex").unwrap();
+        assert_eq!(overridden.program, "/path with spaces/codex");
+        assert_eq!(overridden.args, codex.args);
+        assert_eq!(overridden.default_program, codex.default_program);
+        assert!(overridden.command_overridden && overridden.command_editable);
+        assert_eq!(overridden.source, AgentSource::Builtin);
+        set_builtin_command(dir.path(), "codex", Some("codex")).unwrap();
+        assert!(!list().iter().find(|p| p.id == "codex").unwrap().command_overridden);
+        std::fs::write(
+            dir.path().join("gemini.toml"),
+            "command = \"/registry/gemini\"\n[registry]\nid = \"gemini\"\nversion = \"1.0\"\n",
+        )
+        .unwrap();
+        let registry = list().into_iter().find(|p| p.id == "gemini").unwrap();
+        assert_eq!(registry.default_program.as_deref(), Some("gemini"));
+        assert!(!registry.command_editable);
+        assert_eq!(registry.command_read_only_reason, Some(AgentCommandReadOnlyReason::Registry));
+        assert!(matches!(registry.source, AgentSource::Registry { .. }));
+        std::fs::write(dir.path().join("mine.toml"), "command = \"mine\"\n").unwrap();
+        let custom = list().into_iter().find(|p| p.id == "mine").unwrap();
+        assert_eq!(custom.default_program, None);
+        assert_eq!(custom.command_read_only_reason, Some(AgentCommandReadOnlyReason::CustomAgent));
+    }
+
    #[test]
    fn custom_agents_extend_and_override_the_builtins() {
        let dir = tempfile::tempdir().unwrap();
@@ -230,6 +379,107 @@ mod tests {
        assert!(installed("sh"));
    }

+    #[test]
+    fn set_builtin_env_writes_and_clears_the_environment() {
+        let dir = tempfile::tempdir().unwrap();
+        let env = BTreeMap::from([("CLAUDE_CODE_ENTRYPOINT".to_owned(), "openidea".to_owned())]);
+        set_builtin_env(dir.path(), "claude", env.clone()).unwrap();
+        let claude = load(Some(dir.path())).into_iter().find(|s| s.id == "claude").unwrap();
+        assert_eq!(claude.env, vec![("CLAUDE_CODE_ENTRYPOINT".to_owned(), "openidea".to_owned())]);
+        assert_eq!(describe(&claude).env, env);
+        // The command override and the environment are kept independently.
+        set_builtin_command(dir.path(), "claude", Some("/opt/claude")).unwrap();
+        set_builtin_command(dir.path(), "claude", None).unwrap();
+        assert!(dir.path().join("claude.toml").is_file());
+        set_builtin_env(dir.path(), "claude", BTreeMap::new()).unwrap();
+        assert!(!dir.path().join("claude.toml").exists());
+        set_builtin_env(dir.path(), "not-a-builtin", env).unwrap_err();
+    }
+
+    #[test]
+    fn set_builtin_command_overrides_and_clears_a_builtin() {
+        let dir = tempfile::tempdir().unwrap();
+        set_builtin_command(dir.path(), "not-a-builtin", Some("/x")).unwrap_err();
+        set_builtin_command(dir.path(), "claude", Some("/opt/claude")).unwrap();
+        let claude = load(Some(dir.path())).into_iter().find(|s| s.id == "claude").unwrap();
+        assert_eq!((claude.command.as_str(), claude.driver), ("/opt/claude", Driver::Claude));
+        assert!(claude.args.is_empty());
+        // A registry install is neither overwritten nor removed by a command override.
+        let path = dir.path().join("codex.toml");
+        CustomAgent {
+            name: None,
+            driver: Driver::Acp,
+            command: "amp".into(),
+            args: vec![],
+            env: BTreeMap::new(),
+            registry: Some(RegistryRef { id: "amp-acp".into(), version: "1.0.0".into() }),
+        }
+        .write(&path)
+        .unwrap();
+        set_builtin_command(dir.path(), "codex", Some("/x")).unwrap_err();
+        set_builtin_command(dir.path(), "codex", None).unwrap_err();
+        assert!(path.exists());
+        // Clearing (twice) returns the built-in to auto-detection.
+        set_builtin_command(dir.path(), "claude", None).unwrap();
+        set_builtin_command(dir.path(), "claude", None).unwrap();
+        assert!(!dir.path().join("claude.toml").exists());
+        assert_eq!(load(Some(dir.path())).iter().find(|s| s.id == "claude").unwrap().command, "claude");
+    }
+
+    #[test]
+    fn set_builtin_command_preserves_other_customizations_on_save_and_reset() {
+        let dir = tempfile::tempdir().unwrap();
+        let path = dir.path().join("claude.toml");
+        for field in ["name", "driver", "args", "env", "unnamed"] {
+            let mut agent = CustomAgent {
+                name: Some("Claude Code".into()),
+                driver: Driver::Claude,
+                command: "/old/claude".into(),
+                args: vec![],
+                env: BTreeMap::new(),
+                registry: None,
+            };
+            match field {
+                "name" => agent.name = Some("My Claude".into()),
+                "driver" => agent.driver = Driver::Acp,
+                "args" => agent.args.push("--verbose".into()),
+                "env" => {
+                    agent.env.insert("K".into(), "v".into());
+                }
+                "unnamed" => agent.name = None,
+                _ => unreachable!(),
+            }
+            agent.write(&path).unwrap();
+
+            set_builtin_command(dir.path(), "claude", Some("/new/claude")).unwrap();
+            agent.command = "/new/claude".into();
+            assert_eq!(CustomAgent::read(&path).unwrap(), agent, "{field}");
+
+            set_builtin_command(dir.path(), "claude", None).unwrap();
+            agent.command = "claude".into();
+            assert_eq!(CustomAgent::read(&path).unwrap(), agent, "{field}");
+        }
+    }
+
+    #[test]
+    fn resetting_a_command_only_override_removes_the_file() {
+        let dir = tempfile::tempdir().unwrap();
+        let path = dir.path().join("codex.toml");
+        std::fs::write(
+            &path,
+            "name = \"Codex\"\ndriver = \"codex\"\ncommand = \"/custom/codex\"\nargs = [\"app-server\"]\n",
+        )
+        .unwrap();
+
+        set_builtin_command(dir.path(), "codex", None).unwrap();
+
+        assert!(!path.exists());
+        assert_eq!(
+            load(Some(dir.path())).into_iter().find(|s| s.id == "codex").unwrap(),
+            builtin_spec("codex").unwrap()
+        );
+    }
+
    #[test]
    fn agent_files_round_trip_with_their_registry_table() {
        let dir = tempfile::tempdir().unwrap();
@@ -76,6 +76,8 @@ pub struct RegistryAgent {
    pub installed: Option<String>,
    /// Whether [`Self::version`] is newer than the installed one.
    pub update: bool,
+    /// An install of it is running (it goes on after the Settings page that started it closes).
+    pub installing: bool,
 }

 #[derive(Clone, Copy, Debug, PartialEq, Eq, Serialize, Type)]
@@ -165,6 +167,13 @@ fn parse(text: &str) -> IdeResult<Vec<Entry>> {
        .into_iter()
        .filter_map(|v| serde_json::from_value::<Entry>(v).ok())
        .filter(|e| safe_segment(&e.id) && safe_segment(&e.version))
+        .map(|mut e| {
+            e.id = canonical_id(&e.id).to_owned();
+            if let Some(name) = provider::builtin_name(&e.id) {
+                e.name = name.to_owned();
+            }
+            e
+        })
        .collect())
 }

@@ -232,11 +241,16 @@ fn choose<'a>(entry: &'a Entry, platform: Platform, on_path: &dyn Fn(&str) -> bo
    None
 }

-/// Registry agents that are built-in ones under another id.
-const BUILTIN_ALIASES: &[&str] = &["github-copilot-cli", "qwen-code", "mistral-vibe"];
+/// Registry ids that map to a shorter built-in provider id (`<config>/agents/<id>.toml`).
+const BUILTIN_ALIASES: &[(&str, &str)] =
+    &[("github-copilot-cli", "copilot"), ("qwen-code", "qwen"), ("mistral-vibe", "vibe")];
+
+fn canonical_id(id: &str) -> &str {
+    BUILTIN_ALIASES.iter().find_map(|&(alias, canonical)| (alias == id).then_some(canonical)).unwrap_or(id)
+}

 fn is_builtin(id: &str) -> bool {
-    provider::is_builtin(id) || BUILTIN_ALIASES.contains(&id)
+    provider::is_builtin(canonical_id(id))
 }

 fn on_path(command: &str) -> bool {
@@ -320,6 +334,7 @@ fn visible(
                distribution,
                no_checksum,
                installed,
+                installing: false,
            })
        })
        .collect();
@@ -387,6 +402,7 @@ fn write_atomic(path: &Path, bytes: &[u8]) -> std::io::Result<()> {
 /// Installs (or updates to) the registry's current version of `id`, streaming progress
 /// through `emit`, and points the agent file at it.
 pub fn install(paths: &RegistryPaths, id: &str, cancel: &CancellationToken, emit: Emit) -> IdeResult<()> {
+    let id = canonical_id(id);
    // The saved index is what the user picked from; fetch only when there is none.
    let text = match fs::read_to_string(&paths.cache_file) {
        Ok(text) => text,
@@ -618,6 +634,7 @@ fn install_uv(

 /// Deletes a registry agent's file and installed files.
 pub fn remove(paths: &RegistryPaths, id: &str) -> IdeResult<()> {
+    let id = canonical_id(id);
    if !safe_segment(id) {
        return Err(IdeError::invalid(format!("invalid agent id {id}")));
    }
@@ -812,15 +829,7 @@ mod tests {
        let mut providers: Vec<AgentProvider> = provider::load(Some(&p.agents_dir))
            .into_iter()
            .filter(|s| s.id == "amp-acp")
-            .map(|s| AgentProvider {
-                id: s.id,
-                name: s.name,
-                command: s.command,
-                installed: false,
-                config: vec![],
-                commands: vec![],
-                source: s.source,
-            })
+            .map(|s| provider::describe(&s))
            .collect();
        mark_updates(&p, &mut providers);
        assert_eq!(
@@ -946,4 +955,56 @@ mod tests {
        assert!(remove(&p, "amp-acp").is_err());
        assert!(p.agent_file("amp-acp").exists());
    }
+
+    #[test]
+    fn maps_github_copilot_cli_to_builtin_copilot_and_tracks_updates() {
+        let dir = tempfile::tempdir().unwrap();
+        let p = paths(dir.path());
+        let index = r#"{"agents":[
+            {"id":"github-copilot-cli","name":"Copilot","version":"1.0.105",
+             "description":"GitHub's AI pair programmer",
+             "distribution":{"npx":{"package":"@github/[email protected]","args":["--acp"]}}}
+        ]}"#;
+        let entries = parse(index).unwrap();
+        assert_eq!(entries.len(), 1);
+        assert_eq!((entries[0].id.as_str(), entries[0].name.as_str()), ("copilot", "GitHub Copilot"));
+
+        let shown = visible(&p, &entries, MAC_ARM, &|c| c == "npm" || c == "node");
+        assert_eq!(shown.len(), 1);
+        assert_eq!(
+            (shown[0].id.as_str(), shown[0].name.as_str(), shown[0].installed.as_deref()),
+            ("copilot", "GitHub Copilot", None)
+        );
+
+        CustomAgent {
+            name: Some("GitHub Copilot".into()),
+            driver: Driver::Acp,
+            command: "/data/tools/copilot/1.0.104/node_modules/.bin/copilot".into(),
+            args: vec!["--acp".into()],
+            env: BTreeMap::new(),
+            registry: Some(RegistryRef { id: "copilot".into(), version: "1.0.104".into() }),
+        }
+        .write(&p.agent_file("copilot"))
+        .unwrap();
+
+        let shown = visible(&p, &entries, MAC_ARM, &|c| c == "npm" || c == "node");
+        assert_eq!((shown[0].installed.as_deref(), shown[0].update), (Some("1.0.104"), true));
+
+        write_atomic(&p.cache_file, index.as_bytes()).unwrap();
+        let spec = provider::load(Some(&p.agents_dir)).into_iter().find(|s| s.id == "copilot").unwrap();
+        assert_eq!(spec.name, "GitHub Copilot");
+        assert_eq!(spec.login_hint, "Run `copilot` in a terminal and sign in.");
+        assert_eq!(spec.source, AgentSource::Registry { version: "1.0.104".into(), update: None });
+
+        let mut providers = vec![provider::describe(&spec)];
+        mark_updates(&p, &mut providers);
+        assert_eq!(
+            providers[0].source,
+            AgentSource::Registry { version: "1.0.104".into(), update: Some("1.0.105".into()) }
+        );
+
+        remove(&p, "github-copilot-cli").unwrap();
+        let fallback = provider::load(Some(&p.agents_dir)).into_iter().find(|s| s.id == "copilot").unwrap();
+        assert_eq!(fallback.source, AgentSource::Builtin);
+    }
 }
@@ -9,6 +9,8 @@ struct FakeAgent {
    /// Every connection's agent side, kept open.
    servers: Mutex<Vec<Peer>>,
    calls: Mutex<Vec<String>>,
+    /// Without `loadSession` (a session lives only as long as its process).
+    no_load: bool,
 }

 impl FakeAgent {
@@ -89,7 +91,7 @@ impl Handler for FakeAgent {
                if params.pointer("/clientCapabilities/subagents").is_some_and(Value::is_object) {
                    self.calls.lock().push("subagents".into());
                }
-                Ok(json!({"protocolVersion": 1, "agentCapabilities": {"loadSession": true,
+                Ok(json!({"protocolVersion": 1, "agentCapabilities": {"loadSession": !self.no_load,
                    "sessionCapabilities": {"fork": {}}, "_meta": {"openidea": {"rollback": true, "steer": true}}}}))
            }
            "session/new" => Ok(json!({"sessionId": "s1",
@@ -145,7 +147,16 @@ impl Handler for FakeAgent {
                    json!({"sessionUpdate": "available_commands_update",
                    "availableCommands": [{"name": "review", "description": "Review", "input": {"hint": "focus"}}]}),
                );
-                self.update(&session, json!({"sessionUpdate": "usage_update", "used": 50, "size": 1000}));
+                self.update(
+                    &session,
+                    json!({"sessionUpdate": "usage_update", "used": 50, "size": 1000,
+                    "cost": {"amount": 0.25, "currency": "USD"}}),
+                );
+                self.update(
+                    &session,
+                    json!({"sessionUpdate": LIMITS_UPDATE,
+                    "limits": [{"window": "five_hour", "usedPercent": 19.0, "resetsMs": 5000.0}]}),
+                );
                self.update(&session, json!({"sessionUpdate": "session_info_update", "title": "Lexer fix"}));
                self.say(&session, "Hi");
                self.update(
@@ -358,6 +369,10 @@ async fn a_task_runs_asks_for_permission_and_survives_a_restart() {
        assert_eq!((modes.via, modes.current.as_deref()), (AgentConfigVia::Mode, Some("ask")));
        assert_eq!(t.commands.iter().map(|c| c.name.as_str()).collect::<Vec<_>>(), ["review"]);
        assert_eq!(t.usage.as_ref().map(|u| (u.used, u.size)), Some((50, 1000)));
+        assert_eq!(
+            t.usage.as_ref().and_then(|u| u.cost.clone()),
+            Some(Box::new(AgentCost { amount: 0.25, currency: "USD".into() }))
+        );
        assert_eq!(t.title, "Lexer fix", "the agent's title replaces the prompt's first line");
    }
    mgr.set_config(&task.id, "mode", "code".into()).await.unwrap();
@@ -370,6 +385,18 @@ async fn a_task_runs_asks_for_permission_and_survives_a_restart() {
        assert!(
            events.iter().any(|e| matches!(e, AgentEvent::Task { task } if task.status == AgentStatus::NeedsInput))
        );
+        let limits = events.iter().find_map(|e| match e {
+            AgentEvent::Limits { provider, limits } => Some((provider.as_str(), limits.clone())),
+            _ => None,
+        });
+        assert_eq!(
+            limits,
+            Some((
+                task.provider.as_str(),
+                vec![AgentLimit { window: "five_hour".into(), used_percent: 19.0, resets_ms: Some(5000.0) }]
+            )),
+            "an agent's usage limits are its provider's"
+        );
        let last_entry = events.iter().rev().find_map(|e| match e {
            AgentEvent::Entry { index, entry, .. } if !matches!(entry, AgentEntry::User { .. }) => {
                Some((*index, entry.clone()))
@@ -772,6 +799,18 @@ fn retry_updates_become_a_countdown() {
    assert_eq!(retry_of(&json!({"sessionUpdate": RETRY_UPDATE}), 0.0), None, "no attempt");
 }

+#[test]
+fn usage_limits_and_cost_skip_what_is_malformed() {
+    let limits = config::limits_of(&json!({"sessionUpdate": LIMITS_UPDATE, "limits": [
+        {"window": "seven_day", "usedPercent": 140.0},
+        {"window": "", "usedPercent": 10.0},
+        {"window": "five_hour"},
+    ]}));
+    assert_eq!(limits, [AgentLimit { window: "seven_day".into(), used_percent: 100.0, resets_ms: None }]);
+    let usage = config::usage_of(&json!({"used": 1, "size": 2, "cost": {"amount": -1.0, "currency": "USD"}}));
+    assert_eq!(usage.map(|u| u.cost), Some(None), "a negative cost is dropped, the context use kept");
+}
+
 #[tokio::test(flavor = "multi_thread")]
 async fn cursor_approval_switch_resolves_pending_and_survives_restart() {
    let tmp = tempfile::tempdir().unwrap();
@@ -942,3 +981,242 @@ async fn task_project_root_controls_local_and_worktree_repositories() {
    }
    assert_eq!(git(&["worktree", "list", "--porcelain"]).matches("worktree ").count(), 1);
 }
+
+#[tokio::test(flavor = "multi_thread")]
+async fn reload_providers_updates_registry_install_clears_stale_probes_and_notifies_subscribers() {
+    let tmp = tempfile::tempdir().unwrap();
+    let agents_dir = tmp.path().join("agents");
+    std::fs::create_dir_all(&agents_dir).unwrap();
+    let fake_bin = tmp.path().join(if cfg!(windows) { "copilot.cmd" } else { "copilot" });
+    std::fs::write(&fake_bin, "").unwrap();
+    #[cfg(unix)]
+    {
+        use std::os::unix::fs::PermissionsExt;
+        std::fs::set_permissions(&fake_bin, std::fs::Permissions::from_mode(0o755)).unwrap();
+    }
+
+    let agent = Arc::new(FakeAgent::default());
+    let connector: Connector = {
+        let agent = agent.clone();
+        Arc::new(move |_spec, _cwd, client, _stderr| {
+            let (a, b) = duplex(1 << 20);
+            let (ar, aw) = tokio::io::split(a);
+            let (br, bw) = tokio::io::split(b);
+            let server = Peer::connect_framed(br, bw, agent.clone(), Framing::Lines);
+            agent.servers.lock().push(server);
+            Ok(Peer::connect_framed(ar, aw, client, Framing::Lines))
+        })
+    };
+    let mgr = AgentManager::with_connector(
+        AgentPaths {
+            project_root: tmp.path().to_path_buf(),
+            store_dir: tmp.path().join("store"),
+            worktrees_dir: tmp.path().join("worktrees"),
+            models_file: tmp.path().join("models.json"),
+            custom_agents_dir: Some(agents_dir.clone()),
+            home_dir: None,
+        },
+        tokio::runtime::Handle::current(),
+        connector,
+    );
+
+    // Seed a stale failed probe for copilot before installing its custom TOML.
+    mgr.shared.probes.lock().insert(
+        "copilot".into(),
+        AgentProbe {
+            provider: "copilot".into(),
+            name: None,
+            version: None,
+            protocol: "ACP".into(),
+            capabilities: AgentCapabilities::default(),
+            auth_methods: Vec::new(),
+            error: Some("copilot --acp was not found on PATH.".into()),
+        },
+    );
+
+    let events = Arc::new(Mutex::new(Vec::new()));
+    let events_sink = events.clone();
+    mgr.subscribe(Arc::new(move |ev| events_sink.lock().push(ev)));
+
+    let toml = format!(
+        "name = \"GitHub Copilot\"\ncommand = {:?}\nargs = [\"--acp\", \"--stdio\"]\n",
+        fake_bin.to_string_lossy()
+    );
+    std::fs::write(agents_dir.join("copilot.toml"), toml).unwrap();
+
+    mgr.reload_providers();
+
+    assert!(events.lock().iter().any(|ev| matches!(ev, AgentEvent::Providers)));
+    assert!(!mgr.shared.probes.lock().contains_key("copilot"));
+
+    let copilot = mgr.providers().into_iter().find(|p| p.id == "copilot").unwrap();
+    assert!(copilot.installed);
+    assert!(copilot.command.contains(&*fake_bin.to_string_lossy()));
+
+    let probe = mgr.probe("copilot", false).await.unwrap();
+    assert!(probe.error.is_none());
+}
+
+#[tokio::test(flavor = "multi_thread")]
+async fn idle_agents_stop_and_resume_their_session_on_the_next_message() {
+    let new = || NewAgentTask {
+        project_root: None,
+        prompt: text("again"),
+        provider: "claude".into(),
+        config: Vec::new(),
+        isolation: Isolation::Local,
+        base: None,
+    };
+    let live =
+        |mgr: &AgentManager, id: &str| mgr.task(id).unwrap().live.lock().as_ref().is_some_and(|l| !l.peer.is_closed());
+
+    let tmp = tempfile::tempdir().unwrap();
+    let agent = Arc::new(FakeAgent::default());
+    let mgr = manager(tmp.path(), agent.clone());
+    mgr.set_idle_release(Duration::from_millis(200));
+    let task = mgr.create(new()).await.unwrap();
+    wait_for(&mgr, &task.id, AgentStatus::Ready).await;
+    assert!(live(&mgr, &task.id));
+    // The process is stopped once the task stays idle…
+    tokio::time::sleep(Duration::from_millis(600)).await;
+    assert!(!live(&mgr, &task.id));
+    assert!(agent.servers.lock()[0].is_closed(), "its connection is closed");
+    assert_eq!(mgr.task(&task.id).unwrap().state.lock().task.status, AgentStatus::Ready, "not an error");
+    // …and the next message starts it again on the same session.
+    mgr.prompt(&task.id, text("again"), false).await.unwrap();
+    wait_for(&mgr, &task.id, AgentStatus::Ready).await;
+    assert!(agent.calls.lock().contains(&"session/load".to_owned()));
+    assert_eq!(
+        mgr.entries(&task.id, None).unwrap().iter().filter(|e| matches!(e, AgentEntry::Agent { .. })).count(),
+        2
+    );
+
+    // A new turn before the delay ran out keeps the agent.
+    mgr.prompt(&task.id, text("again"), false).await.unwrap();
+    tokio::time::sleep(Duration::from_millis(100)).await;
+    wait_for(&mgr, &task.id, AgentStatus::Ready).await;
+    assert!(live(&mgr, &task.id));
+    mgr.shutdown();
+
+    // An agent that can't reload its session keeps running: stopping it would lose the conversation.
+    let tmp = tempfile::tempdir().unwrap();
+    let agent = Arc::new(FakeAgent { no_load: true, ..FakeAgent::default() });
+    let mgr = manager(tmp.path(), agent.clone());
+    mgr.set_idle_release(Duration::from_millis(200));
+    let task = mgr.create(new()).await.unwrap();
+    wait_for(&mgr, &task.id, AgentStatus::Ready).await;
+    tokio::time::sleep(Duration::from_millis(600)).await;
+    assert!(live(&mgr, &task.id));
+    mgr.shutdown();
+}
+
+/// Deleting a task whose agent still runs in the worktree removes both and leaves no
+/// process behind, whether it is waiting for permission or idle without session/load.
+#[tokio::test(flavor = "multi_thread")]
+async fn deleting_a_task_waits_for_its_agent_to_exit_before_removing_the_worktree() {
+    for no_load in [false, true] {
+        delete_running_agent(no_load).await;
+    }
+}
+
+async fn delete_running_agent(no_load: bool) {
+    let tmp = tempfile::tempdir().unwrap();
+    let root = dunce::canonicalize(tmp.path()).unwrap();
+    let git = |args: &[&str]| {
+        let out = std::process::Command::new("git")
+            .args(["-c", "user.name=t", "-c", "user.email=t@t", "-c", "commit.gpgsign=false"])
+            .args(args)
+            .current_dir(&root)
+            .output()
+            .unwrap();
+        assert!(out.status.success(), "{}", String::from_utf8_lossy(&out.stderr));
+    };
+    git(&["init", "-q", "-b", "main"]);
+    std::fs::write(root.join("file.txt"), "original\n").unwrap();
+    git(&["add", "."]);
+    git(&["commit", "-qm", "initial"]);
+
+    let agent = Arc::new(FakeAgent { no_load, ..FakeAgent::default() });
+    let pids: Arc<Mutex<Vec<u32>>> = Arc::default();
+    let (fake, started) = (agent.clone(), pids.clone());
+    // The fake agent, served on behalf of a real process that exits only when killed.
+    let connector: Connector = Arc::new(move |_spec, cwd, client, _stderr| {
+        #[cfg(unix)]
+        let mut cmd = {
+            let mut cmd = tokio::process::Command::new("sleep");
+            cmd.arg("30");
+            cmd
+        };
+        #[cfg(windows)]
+        let mut cmd = {
+            let mut cmd = tokio::process::Command::new("cmd");
+            cmd.args(["/D", "/C", "echo ready>agent-ready & ping -n 30 127.0.0.1 >nul"]);
+            cmd
+        };
+        ide_core::process::prepare(cmd.as_std_mut());
+        ide_core::process::own_group(cmd.as_std_mut());
+        cmd.current_dir(cwd).kill_on_drop(true);
+        let child = cmd.spawn()?;
+        started.lock().push(child.id().unwrap());
+        let (a, b) = duplex(1 << 20);
+        let (ar, aw) = tokio::io::split(a);
+        let (br, bw) = tokio::io::split(b);
+        // `connect_with_child` frames with Content-Length.
+        fake.servers.lock().push(Peer::connect(br, bw, fake.clone()));
+        Ok(Peer::connect_with_child(ar, aw, client, child))
+    });
+    let mgr = AgentManager::with_connector(
+        AgentPaths {
+            project_root: root.clone(),
+            store_dir: root.join("store"),
+            worktrees_dir: root.join("worktrees"),
+            models_file: root.join("models.json"),
+            custom_agents_dir: None,
+            home_dir: None,
+        },
+        tokio::runtime::Handle::current(),
+        connector,
+    );
+    let task = mgr
+        .create(NewAgentTask {
+            project_root: None,
+            prompt: text(if no_load { "again" } else { "Fix the lexer" }),
+            provider: "claude".into(),
+            config: vec![],
+            isolation: Isolation::Worktree,
+            base: None,
+        })
+        .await
+        .unwrap();
+    wait_for(&mgr, &task.id, if no_load { AgentStatus::Ready } else { AgentStatus::NeedsInput }).await;
+    let pid = *pids.lock().last().expect("the agent was started");
+
+    #[cfg(windows)]
+    {
+        tokio::time::timeout(Duration::from_secs(5), async {
+            while !task.cwd.0.join("agent-ready").exists() {
+                tokio::time::sleep(Duration::from_millis(10)).await;
+            }
+        })
+        .await
+        .unwrap();
+        assert_eq!(
+            std::fs::rename(&task.cwd.0, task.cwd.0.with_extension("moved")).unwrap_err().raw_os_error(),
+            Some(32),
+            "the running agent really locks its worktree"
+        );
+    }
+
+    mgr.delete(&task.id, true).await.unwrap();
+    assert!(!task.cwd.0.exists());
+    // Killed and reaped: not even a zombie is left.
+    #[cfg(unix)]
+    let alive = std::process::Command::new("kill").args(["-0", &pid.to_string()]).status().unwrap().success();
+    #[cfg(windows)]
+    let alive = {
+        let mut cmd = std::process::Command::new("tasklist");
+        ide_core::process::prepare(&mut cmd).args(["/FI", &format!("PID eq {pid}"), "/FO", "CSV", "/NH"]);
+        String::from_utf8_lossy(&cmd.output().unwrap().stdout).contains(&format!("\"{pid}\""))
+    };
+    assert!(!alive, "the agent (pid {pid}) is still running");
+}
@@ -5,7 +5,7 @@ use ide_core::{IdeError, IdeResult, IpcPath};
 use ide_vcs::{ChangeKind, Repo};
 use std::collections::BTreeMap;
 use std::path::{Path, PathBuf};
-use std::time::UNIX_EPOCH;
+use std::time::{Duration, UNIX_EPOCH};

 pub(crate) struct Created {
    pub path: PathBuf,
@@ -48,8 +48,44 @@ pub(crate) fn create(project_root: &Path, worktrees_dir: &Path, title: &str, bas
    Ok(Created { path, branch, base, base_commit })
 }

-pub(crate) fn remove(project_root: &Path, path: &Path) -> IdeResult<()> {
-    repo_at(project_root)?.remove_worktree(path, true)
+/// `git worktree remove --force -- <path>`. When git no longer recognizes the
+/// worktree (a pruned registration, a moved repository, a deleted `.git` file)
+/// it fails with "is not a working tree". A folder under `worktrees_dir` is still
+/// ours, so it is removed directly to keep the task deletable (a stale
+/// registration prunes later); anything else keeps git's error.
+pub(crate) fn remove(project_root: &Path, worktrees_dir: &Path, path: &Path) -> IdeResult<()> {
+    let repo = repo_at(project_root)?;
+    let err = match repo.remove_worktree(path, true) {
+        Ok(()) => return Ok(()),
+        Err(e) => e,
+    };
+    if !path.exists() {
+        return Ok(());
+    }
+    if !path.starts_with(worktrees_dir) || path == worktrees_dir {
+        return Err(err);
+    }
+    retrying(REMOVE_ATTEMPTS, REMOVE_PAUSE, || std::fs::remove_dir_all(path))
+        .map_err(|e| IdeError::internal(format!("{}: {e}", path.display())))
+}
+
+/// On Windows a folder can't be deleted while a process still has a file in it open
+/// (os error 32): an agent's helper that outlived it, an antivirus scan, the search indexer.
+/// Those let go within moments, so removing is retried for a few seconds.
+const REMOVE_ATTEMPTS: u32 = 10;
+const REMOVE_PAUSE: Duration = Duration::from_millis(300);
+
+fn retrying(attempts: u32, pause: Duration, mut op: impl FnMut() -> std::io::Result<()>) -> std::io::Result<()> {
+    for _ in 1..attempts {
+        match op() {
+            Err(e) if e.kind() != std::io::ErrorKind::NotFound => std::thread::sleep(pause),
+            _ => return Ok(()),
+        }
+    }
+    match op() {
+        Err(e) if e.kind() == std::io::ErrorKind::NotFound => Ok(()),
+        r => r,
+    }
 }

 /// Files under `cwd` that differ from `base` (untracked files included), with line counts.
@@ -133,6 +169,54 @@ fn unique_slug(base: &str, taken: impl Fn(&str) -> bool) -> String {
 mod tests {
    use super::*;

+    #[test]
+    fn removing_is_retried_while_a_file_is_still_in_use() {
+        use std::io::{Error, ErrorKind};
+        // A sharing violation as Windows reports it (os error 32), a vanished folder, other errors.
+        let in_use = || Error::from_raw_os_error(32);
+        for (fails, outcome) in [(0, true), (3, true), (REMOVE_ATTEMPTS - 1, true), (REMOVE_ATTEMPTS, false)] {
+            let mut calls = 0;
+            let r = retrying(REMOVE_ATTEMPTS, Duration::ZERO, || {
+                calls += 1;
+                if calls <= fails { Err(in_use()) } else { Ok(()) }
+            });
+            assert_eq!(r.is_ok(), outcome, "{fails} failures");
+            assert_eq!(calls, (fails + 1).min(REMOVE_ATTEMPTS));
+        }
+        let mut calls = 0;
+        let gone = retrying(REMOVE_ATTEMPTS, Duration::ZERO, || {
+            calls += 1;
+            if calls == 1 { Err(in_use()) } else { Err(Error::from(ErrorKind::NotFound)) }
+        });
+        assert!(gone.is_ok(), "deleted meanwhile: done");
+        assert_eq!(calls, 2);
+    }
+
+    #[cfg(windows)]
+    #[test]
+    fn removing_waits_for_a_windows_file_lock_to_be_released() {
+        use std::os::windows::fs::OpenOptionsExt;
+        let tmp = tempfile::tempdir().unwrap();
+        let repo = tmp.path().join("repo");
+        std::fs::create_dir(&repo).unwrap();
+        git(&repo, &["init", "-q", "-b", "main"]);
+        std::fs::write(repo.join("a.txt"), "one\n").unwrap();
+        git(&repo, &["add", "."]);
+        git(&repo, &["commit", "-q", "-m", "init"]);
+        let worktrees = tmp.path().join("wt");
+        let created = create(&repo, &worktrees, "Locked file", None).unwrap();
+        let file = std::fs::OpenOptions::new().read(true).share_mode(0).open(created.path.join("a.txt")).unwrap();
+        assert_eq!(std::fs::remove_file(created.path.join("a.txt")).unwrap_err().raw_os_error(), Some(32));
+        let release = std::thread::spawn(move || {
+            std::thread::sleep(Duration::from_millis(800));
+            drop(file);
+        });
+        let result = remove(&repo, &worktrees, &created.path);
+        release.join().unwrap();
+        result.unwrap();
+        assert!(!created.path.exists());
+    }
+
    #[test]
    fn slugs_are_branch_safe() {
        assert_eq!(slugify("Fix lexer UTF-16 columns!"), "fix-lexer-utf-16-columns");
@@ -153,7 +237,7 @@ mod tests {
        assert!(snapshot(&dir).unwrap().is_empty());
        assert_eq!(file_at(&dir, &dir.join("a.txt"), "HEAD").unwrap(), None);
        assert!(create(&dir, &tmp.path().join("wt"), "Edit A", None).is_err());
-        assert!(remove(&dir, &dir).is_err());
+        assert!(remove(&dir, tmp.path(), &dir).is_err());
    }

    fn git(dir: &Path, args: &[&str]) {
@@ -202,7 +286,38 @@ mod tests {

        // A second task with the same title gets its own worktree.
        assert_eq!(create(&repo, &tmp.path().join("wt"), "Edit A", None).unwrap().branch, "agent/edit-a-2");
-        remove(&repo, &created.path).unwrap();
+        remove(&repo, &tmp.path().join("wt"), &created.path).unwrap();
        assert!(!created.path.exists());
    }
+
+    #[test]
+    fn a_broken_worktree_registration_still_leaves_a_deletable_folder() {
+        let tmp = tempfile::tempdir().unwrap();
+        let repo = tmp.path().join("repo");
+        std::fs::create_dir(&repo).unwrap();
+        git(&repo, &["init", "-q", "-b", "main"]);
+        std::fs::write(repo.join("a.txt"), "one\n").unwrap();
+        git(&repo, &["add", "."]);
+        git(&repo, &["commit", "-q", "-m", "init"]);
+
+        // A pruned registration (the repository moved, `git worktree prune` ran).
+        let created = create(&repo, &tmp.path().join("wt"), "Edit A", None).unwrap();
+        let registration = repo.join(".git/worktrees").join(created.path.file_name().unwrap());
+        std::fs::remove_dir_all(registration).unwrap();
+        remove(&repo, &tmp.path().join("wt"), &created.path).unwrap();
+        assert!(!created.path.exists());
+
+        // A deleted `.git` file in the worktree itself.
+        let created = create(&repo, &tmp.path().join("wt"), "Edit B", None).unwrap();
+        std::fs::remove_file(created.path.join(".git")).unwrap();
+        remove(&repo, &tmp.path().join("wt"), &created.path).unwrap();
+        assert!(!created.path.exists());
+
+        // A folder outside the worktrees directory is never deleted by hand.
+        let elsewhere = tmp.path().join("elsewhere");
+        std::fs::create_dir(&elsewhere).unwrap();
+        std::fs::write(elsewhere.join("keep.txt"), "x\n").unwrap();
+        assert!(remove(&repo, &tmp.path().join("wt"), &elsewhere).is_err());
+        assert!(elsewhere.join("keep.txt").exists());
+    }
 }
@@ -0,0 +1,15 @@
+[package]
+name = "ide-android"
+description = "Android devices and logcat for the Logcat tool window, driven through the adb CLI"
+version.workspace = true
+edition.workspace = true
+license.workspace = true
+
+[dependencies]
+ide-core.workspace = true
+serde.workspace = true
+specta.workspace = true
+which = "8"
+
+[dev-dependencies]
+tempfile.workspace = true
@@ -0,0 +1,222 @@
+//! Android devices and their logs, driven through the `adb` CLI (like git is
+//! driven through its CLI).
+//!
+//! The Logcat tool window needs two things from a device: that it is there, and
+//! what it prints. Both come from `adb`, which the Android SDK installs — the
+//! IDE does not bundle it.
+//!
+//! Every function blocks; callers run them off the UI / command threads.
+
+mod model;
+mod process;
+
+pub use model::*;
+
+use ide_core::{CancellationToken, IdeError, IdeResult};
+use std::path::{Path, PathBuf};
+use std::process::Command;
+use std::sync::OnceLock;
+use std::time::Duration;
+
+/// `adb devices` is quick unless it starts the daemon, which can take a moment.
+const DEVICES: Duration = Duration::from_secs(20);
+/// `adb logcat -c` only truncates the buffers.
+const CLEAR: Duration = Duration::from_secs(15);
+/// How much of the buffer to show before following, so opening the window is not empty.
+const TAIL_LINES: u32 = 200;
+/// Logcat can print thousands of lines a second: batches keep the IPC channel sane,
+/// while `IDLE` makes sure a quiet stream still shows its last line promptly.
+const BATCH_IDLE: Duration = Duration::from_millis(60);
+const BATCH_MAX: usize = 300;
+
+fn exe(name: &str) -> String {
+    if cfg!(windows) { format!("{name}.exe") } else { name.to_owned() }
+}
+
+/// Android SDK locations, most specific first: the environment, then the usual
+/// per-platform installs (a GUI app on macOS does not see a shell's `ANDROID_HOME`).
+fn sdk_roots() -> Vec<PathBuf> {
+    let mut roots: Vec<PathBuf> = ["ANDROID_HOME", "ANDROID_SDK_ROOT"]
+        .iter()
+        .filter_map(|key| std::env::var_os(key).map(PathBuf::from))
+        .collect();
+    let home = std::env::var_os(if cfg!(windows) { "USERPROFILE" } else { "HOME" }).map(PathBuf::from);
+    if let Some(home) = home.filter(|_| !cfg!(windows)) {
+        roots.push(home.join("Library/Android/sdk"));
+        roots.push(home.join("Android/Sdk"));
+    }
+    if cfg!(windows)
+        && let Some(local) = std::env::var_os("LOCALAPPDATA").map(PathBuf::from)
+    {
+        roots.push(local.join("Android/Sdk"));
+    }
+    roots
+}
+
+/// Locates the adb executable once per process; `OPENIDEA_ADB` overrides.
+pub fn adb_executable() -> Option<PathBuf> {
+    static ADB: OnceLock<Option<PathBuf>> = OnceLock::new();
+    ADB.get_or_init(|| {
+        if let Some(explicit) = std::env::var_os("OPENIDEA_ADB").map(PathBuf::from).filter(|p| p.is_file()) {
+            return Some(explicit);
+        }
+        let name = exe("adb");
+        if let Some(found) =
+            sdk_roots().into_iter().map(|root| root.join("platform-tools").join(&name)).find(|p| p.is_file())
+        {
+            return Some(found);
+        }
+        if let Ok(found) = which::which("adb") {
+            return Some(found);
+        }
+        let mut candidates: Vec<PathBuf> = if cfg!(windows) {
+            vec![PathBuf::from(r"C:\platform-tools\adb.exe")]
+        } else {
+            ["/usr/local/bin/adb", "/opt/homebrew/bin/adb", "/usr/bin/adb"].iter().map(PathBuf::from).collect()
+        };
+        candidates.extend([
+            PathBuf::from("/opt/android-sdk/platform-tools/adb"),
+            PathBuf::from("/usr/lib/android-sdk/platform-tools/adb"),
+        ]);
+        candidates.into_iter().find(|p: &PathBuf| p.is_file())
+    })
+    .clone()
+}
+
+fn executable() -> IdeResult<PathBuf> {
+    adb_executable().ok_or_else(|| {
+        IdeError::unavailable(
+            "adb was not found: install the Android SDK platform-tools, or set ANDROID_HOME (or OPENIDEA_ADB)",
+        )
+    })
+}
+
+/// The directory holding adb, for command lines that expect `adb` on `PATH`.
+pub fn platform_tools_dir() -> Option<&'static Path> {
+    static DIR: OnceLock<Option<PathBuf>> = OnceLock::new();
+    DIR.get_or_init(|| adb_executable().as_deref().and_then(Path::parent).map(Path::to_path_buf)).as_deref()
+}
+
+/// Connected devices, online ones first; starting the adb daemon when needed.
+pub fn devices() -> IdeResult<Vec<AndroidDevice>> {
+    let adb = executable()?;
+    let mut cmd = Command::new(adb);
+    cmd.args(["devices", "-l"]);
+    let out = process::run(cmd, DEVICES, None)?;
+    if !out.success {
+        let message = out.stderr.trim();
+        return Err(IdeError::unavailable(if message.is_empty() {
+            "adb devices failed".to_owned()
+        } else {
+            format!("adb devices failed: {message}")
+        }));
+    }
+    Ok(parse_devices(&out.stdout))
+}
+
+/// Empties the device's log buffers (`adb logcat -c`).
+pub fn clear_log(serial: &str, cancel: &CancellationToken) -> IdeResult<()> {
+    let adb = executable()?;
+    let mut cmd = Command::new(adb);
+    cmd.args(["-s", serial, "logcat", "-c"]);
+    let out = process::run(cmd, CLEAR, Some(cancel))?;
+    if out.success {
+        Ok(())
+    } else {
+        Err(IdeError::unavailable(format!("adb logcat -c failed: {}", out.stderr.trim())))
+    }
+}
+
+fn command(adb: &Path, serial: &str, tail: Option<u32>) -> Command {
+    let mut cmd = Command::new(adb);
+    cmd.args(["-s", serial, "logcat", "-v", "threadtime"]);
+    if let Some(lines) = tail {
+        // Recent history first, then follow: `-T <count>` is lines, not an exit.
+        cmd.arg("-T").arg(lines.to_string());
+    }
+    cmd
+}
+
+/// Follows `serial`'s log until `cancel` fires, handing lines over in batches.
+/// With `clear`, the buffers are emptied first so the window starts clean.
+pub fn logcat(
+    serial: &str,
+    clear: bool,
+    cancel: &CancellationToken,
+    on_batch: &mut dyn FnMut(Vec<LogcatLine>),
+) -> IdeResult<()> {
+    let adb = executable()?;
+    if clear {
+        clear_log(serial, cancel)?;
+    }
+    let mut parse = |line: &str| Some(parse_line(line));
+    let (ok, stderr) = match process::stream_batched(
+        command(&adb, serial, Some(TAIL_LINES)),
+        cancel,
+        BATCH_IDLE,
+        BATCH_MAX,
+        &mut parse,
+        on_batch,
+    ) {
+        Ok(result) => result,
+        // The window closed or switched devices: stopping is the expected end.
+        Err(e) if e.kind == ide_core::error::ErrorKind::Cancelled => return Ok(()),
+        Err(e) => return Err(e),
+    };
+    if ok || cancel.is_cancelled() {
+        return Ok(());
+    }
+    // `-T` is old (API 21) but adb forwards logcat options it does not know on
+    // very old devices; retry without the history rather than showing nothing.
+    let unsupported = stderr.iter().any(|line| {
+        line.contains("Unrecognized option") || line.contains("unknown option") || line.contains("Invalid option")
+    });
+    if unsupported {
+        let (ok, stderr) = match process::stream_batched(
+            command(&adb, serial, None),
+            cancel,
+            BATCH_IDLE,
+            BATCH_MAX,
+            &mut parse,
+            on_batch,
+        ) {
+            Ok(result) => result,
+            Err(e) if e.kind == ide_core::error::ErrorKind::Cancelled => return Ok(()),
+            Err(e) => return Err(e),
+        };
+        if ok || cancel.is_cancelled() {
+            return Ok(());
+        }
+        return Err(failure(serial, &stderr));
+    }
+    Err(failure(serial, &stderr))
+}
+
+fn failure(serial: &str, stderr: &[String]) -> IdeError {
+    let message = stderr.join("\n");
+    IdeError::unavailable(if message.trim().is_empty() {
+        format!("adb logcat on {serial} stopped")
+    } else {
+        format!("adb logcat on {serial} stopped: {message}")
+    })
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn adb_candidates_are_absolute() {
+        for root in sdk_roots() {
+            assert!(root.is_absolute(), "{root:?}");
+        }
+    }
+
+    #[test]
+    fn executable_is_absolute_when_found() {
+        if let Some(adb) = adb_executable() {
+            assert!(adb.is_absolute());
+            assert!(adb.is_file());
+        }
+    }
+}
@@ -0,0 +1,276 @@
+//! What the Logcat tool window shows: the devices `adb` reports and the lines
+//! `adb logcat` prints, parsed from its `threadtime` format.
+
+use serde::{Deserialize, Serialize};
+use specta::Type;
+
+/// One entry of `adb devices -l`.
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize, Type)]
+#[serde(rename_all = "camelCase")]
+pub struct AndroidDevice {
+    /// `adb -s` value: a USB serial number, `emulator-5554`, or `host:port`.
+    pub serial: String,
+    /// `device` (usable), `offline`, `unauthorized` or `no permissions`.
+    pub state: String,
+    pub model: Option<String>,
+    pub product: Option<String>,
+    /// The device's own name from the build (`ro.product.device`).
+    pub device: Option<String>,
+    pub transport_id: Option<String>,
+}
+
+impl AndroidDevice {
+    /// Ready for `logcat` / `install`.
+    pub fn is_online(&self) -> bool {
+        self.state == "device"
+    }
+
+    /// What the picker calls it: the model when known, the serial otherwise.
+    pub fn label(&self) -> &str {
+        self.model.as_deref().filter(|m| !m.trim().is_empty()).unwrap_or(&self.serial)
+    }
+}
+
+/// The single-letter logcat priority, in increasing severity.
+#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Serialize, Deserialize, Type)]
+#[serde(rename_all = "camelCase")]
+pub enum LogcatLevel {
+    Verbose,
+    Debug,
+    Info,
+    Warn,
+    Error,
+    Fatal,
+    /// A line logcat prints outside the message format (`--------- beginning of main`).
+    Unknown,
+}
+
+impl LogcatLevel {
+    pub fn letter(self) -> char {
+        match self {
+            Self::Verbose => 'V',
+            Self::Debug => 'D',
+            Self::Info => 'I',
+            Self::Warn => 'W',
+            Self::Error => 'E',
+            Self::Fatal => 'F',
+            Self::Unknown => '?',
+        }
+    }
+
+    fn parse(c: char) -> Self {
+        match c.to_ascii_uppercase() {
+            'V' => Self::Verbose,
+            'D' => Self::Debug,
+            'I' => Self::Info,
+            'W' => Self::Warn,
+            'E' => Self::Error,
+            'F' | 'A' => Self::Fatal,
+            _ => Self::Unknown,
+        }
+    }
+}
+
+/// One [`LogcatLevel`]-tagged line of `adb logcat -v threadtime`.
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize, Type)]
+#[serde(rename_all = "camelCase")]
+pub struct LogcatLine {
+    /// `MM-DD HH:MM:SS.mmm`, as logcat prints it (no year, device time zone).
+    pub time: String,
+    pub pid: i32,
+    pub tid: i32,
+    pub level: LogcatLevel,
+    pub tag: String,
+    pub message: String,
+}
+
+impl LogcatLine {
+    /// A line logcat printed outside the message format, kept so nothing is lost.
+    fn unparsed(text: &str) -> Self {
+        Self {
+            time: String::new(),
+            pid: 0,
+            tid: 0,
+            level: LogcatLevel::Unknown,
+            tag: String::new(),
+            message: text.to_owned(),
+        }
+    }
+}
+
+/// Parses `adb devices -l` output; the daemon's chatter on stderr is not included.
+pub fn parse_devices(output: &str) -> Vec<AndroidDevice> {
+    let mut devices: Vec<AndroidDevice> = Vec::new();
+    for line in output.lines() {
+        let line = line.trim_end();
+        if line.trim().is_empty() || line.starts_with("List of devices") || line.starts_with('*') {
+            continue;
+        }
+        let mut fields = line.split_whitespace();
+        let (Some(serial), Some(state)) = (fields.next(), fields.next()) else {
+            continue;
+        };
+        // "no permissions (user in plugdev group; are your udev rules wrong?)"
+        // is the one state that carries spaces; the rest is a `key:value` list.
+        let mut device = AndroidDevice {
+            serial: serial.to_owned(),
+            state: state.to_owned(),
+            model: None,
+            product: None,
+            device: None,
+            transport_id: None,
+        };
+        if device.state == "no" {
+            device.state = "no permissions".to_owned();
+            devices.push(device);
+            continue;
+        }
+        for field in fields {
+            let Some((key, value)) = field.split_once(':') else {
+                continue;
+            };
+            match key {
+                "model" => device.model = Some(value.to_owned()),
+                "product" => device.product = Some(value.to_owned()),
+                "device" => device.device = Some(value.to_owned()),
+                "transport_id" => device.transport_id = Some(value.to_owned()),
+                _ => {}
+            }
+        }
+        devices.push(device);
+    }
+    // Online first, then by name, so the picker's default is the device in hand.
+    devices.sort_by(|a, b| b.is_online().cmp(&a.is_online()).then_with(|| a.serial.cmp(&b.serial)));
+    devices
+}
+
+/// Parses one `logcat -v threadtime` line:
+///
+/// ```text
+/// 11-04 12:52:39.123  3048  3059 I WindowManager: displayed
+/// ```
+///
+/// Text that does not follow the format still becomes a line, so a device that
+/// prints something unexpected does not look like a dead stream.
+pub fn parse_line(text: &str) -> LogcatLine {
+    let Some(line) = parse_formatted(text) else {
+        return LogcatLine::unparsed(text);
+    };
+    line
+}
+
+fn parse_formatted(text: &str) -> Option<LogcatLine> {
+    // "MM-DD HH:MM:SS.mmm" is 18 bytes; logcat pads the rest with spaces.
+    let stamp = text.get(..18)?;
+    if !looks_like_stamp(stamp) {
+        return None;
+    }
+    let mut rest = text.get(18..)?;
+    let pid: i32 = take_field(&mut rest)?.parse().ok()?;
+    let tid: i32 = take_field(&mut rest)?.parse().ok()?;
+    let level = LogcatLevel::parse(take_field(&mut rest)?.chars().next()?);
+    let tail = rest.trim_start();
+    // "Tag            : message": logcat pads the tag to 8 columns, and the tag
+    // itself never contains a colon followed by a space.
+    let (tag, message) = match tail.split_once(": ") {
+        Some((tag, message)) => (tag.trim_end(), message),
+        None => (tail.trim_end(), ""),
+    };
+    Some(LogcatLine { time: stamp.to_owned(), pid, tid, level, tag: tag.to_owned(), message: message.to_owned() })
+}
+
+/// Consumes the next space-separated field of `rest`, leaving the remainder.
+fn take_field<'a>(rest: &mut &'a str) -> Option<&'a str> {
+    *rest = rest.trim_start();
+    if rest.is_empty() {
+        return None;
+    }
+    let end = rest.find(char::is_whitespace).unwrap_or(rest.len());
+    let field = &rest[..end];
+    *rest = &rest[end..];
+    Some(field)
+}
+
+fn looks_like_stamp(s: &str) -> bool {
+    let bytes = s.as_bytes();
+    bytes.len() == 18
+        && bytes[2] == b'-'
+        && bytes[5] == b' '
+        && bytes[8] == b':'
+        && bytes[11] == b':'
+        && bytes[14] == b'.'
+        && bytes.iter().enumerate().all(|(i, b)| matches!(i, 2 | 5 | 8 | 11 | 14) || b.is_ascii_digit())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn reads_adb_devices_with_attributes() {
+        let out = "\
+List of devices attached
+HT7A1B2C3D4           device product:generic model:Generic_Phone device:generic transport_id:1
+emulator-5554          offline transport_id:2
+0123456789ABCDEF       unauthorized usb:1-1 transport_id:3
+
+";
+        let devices = parse_devices(out);
+        assert_eq!(devices.len(), 3);
+        // Online first, then by serial.
+        assert_eq!(devices[0].serial, "HT7A1B2C3D4");
+        assert_eq!(devices[0].state, "device");
+        assert_eq!(devices[0].model.as_deref(), Some("Generic_Phone"));
+        assert_eq!(devices[0].transport_id.as_deref(), Some("1"));
+        assert!(devices[0].is_online());
+        assert_eq!(devices[1].serial, "0123456789ABCDEF");
+        assert_eq!(devices[1].state, "unauthorized");
+        assert_eq!(devices[1].label(), "0123456789ABCDEF");
+        assert_eq!(devices[2].serial, "emulator-5554");
+        assert!(!devices[2].is_online());
+    }
+
+    #[test]
+    fn reads_adb_devices_when_the_list_is_empty() {
+        assert!(parse_devices("List of devices attached\n\n").is_empty());
+    }
+
+    #[test]
+    fn reads_no_permissions() {
+        let devices = parse_devices("ABC\tno permissions (user in plugdev group; are your udev rules wrong?)\n");
+        assert_eq!(devices.len(), 1);
+        assert_eq!(devices[0].state, "no permissions");
+    }
+
+    #[test]
+    fn parses_a_threadtime_line() {
+        let line = parse_line("11-04 12:52:39.123  3048  3059 I WindowManager: Displayed activity");
+        assert_eq!(line.time, "11-04 12:52:39.123");
+        assert_eq!(line.pid, 3048);
+        assert_eq!(line.tid, 3059);
+        assert_eq!(line.level, LogcatLevel::Info);
+        assert_eq!(line.tag, "WindowManager");
+        assert_eq!(line.message, "Displayed activity");
+    }
+
+    #[test]
+    fn keeps_colons_in_the_message() {
+        let line = parse_line("11-04 12:52:39.123  3048  3059 E flutter : java.lang.IllegalStateException: boom");
+        assert_eq!(line.tag, "flutter");
+        assert_eq!(line.level, LogcatLevel::Error);
+        assert_eq!(line.message, "java.lang.IllegalStateException: boom");
+    }
+
+    #[test]
+    fn keeps_lines_outside_the_format() {
+        let line = parse_line("--------- beginning of main");
+        assert_eq!(line.level, LogcatLevel::Unknown);
+        assert_eq!(line.message, "--------- beginning of main");
+    }
+
+    #[test]
+    fn levels_order_by_severity() {
+        assert!(LogcatLevel::Warn > LogcatLevel::Info);
+        assert!(LogcatLevel::Fatal > LogcatLevel::Error);
+    }
+}
@@ -0,0 +1,206 @@
+//! Child processes of the `adb` CLI: bounded runs, and cancellable line streams
+//! that are handed over in batches (logcat is far too chatty for one message a line).
+
+use ide_core::process::terminate_tree;
+use ide_core::{CancellationToken, IdeError, IdeResult};
+use std::io::Read;
+use std::process::{Child, Command, Stdio};
+use std::sync::mpsc;
+use std::time::{Duration, Instant};
+
+/// How long a cancelled child gets to exit on `SIGTERM` (and flush) before `SIGKILL`.
+const KILL_GRACE: Duration = Duration::from_millis(20);
+
+pub(crate) struct Output {
+    pub stdout: String,
+    pub stderr: String,
+    pub success: bool,
+}
+
+fn prepare(cmd: &mut Command) {
+    cmd.stdin(Stdio::null()).stdout(Stdio::piped()).stderr(Stdio::piped());
+    ide_core::process::prepare(ide_core::process::own_group(cmd));
+}
+
+fn spawn(cmd: &mut Command) -> IdeResult<Child> {
+    cmd.spawn().map_err(|e| IdeError::unavailable(format!("could not run adb: {e}")))
+}
+
+fn read_all(mut pipe: impl Read + Send + 'static) -> std::thread::JoinHandle<String> {
+    std::thread::spawn(move || {
+        let mut buf = Vec::new();
+        let _ = pipe.read_to_end(&mut buf);
+        ide_core::output_encoding::decode_tool_output(&buf)
+    })
+}
+
+/// Runs `cmd` to completion. Fails when it outlives `timeout` or `cancel` fires;
+/// a non-zero exit is reported in [`Output::success`], not as an error.
+pub(crate) fn run(mut cmd: Command, timeout: Duration, cancel: Option<&CancellationToken>) -> IdeResult<Output> {
+    prepare(&mut cmd);
+    let mut child = spawn(&mut cmd)?;
+    let out = child.stdout.take().map(read_all);
+    let err = child.stderr.take().map(read_all);
+    let deadline = Instant::now() + timeout;
+    let status = loop {
+        if let Some(status) = child.try_wait()? {
+            break status;
+        }
+        if cancel.is_some_and(CancellationToken::is_cancelled) {
+            terminate_tree(&mut child, KILL_GRACE);
+            return Err(IdeError::cancelled());
+        }
+        if Instant::now() >= deadline {
+            terminate_tree(&mut child, KILL_GRACE);
+            return Err(IdeError::unavailable("adb did not respond in time"));
+        }
+        std::thread::sleep(Duration::from_millis(10));
+    };
+    Ok(Output {
+        stdout: out.map(|t| t.join().unwrap_or_default()).unwrap_or_default(),
+        stderr: err.map(|t| t.join().unwrap_or_default()).unwrap_or_default(),
+        success: status.success(),
+    })
+}
+
+enum Event {
+    Line(bool, String),
+    Closed,
+}
+
+fn spawn_reader(mut pipe: impl Read + Send + 'static, tx: mpsc::Sender<Event>, stdout: bool) {
+    std::thread::spawn(move || {
+        let mut buf = [0u8; 8192];
+        let mut pending: Vec<u8> = Vec::new();
+        let flush = |pending: &mut Vec<u8>| {
+            if !pending.is_empty() {
+                let line = ide_core::output_encoding::decode_tool_output(pending);
+                pending.clear();
+                let _ = tx.send(Event::Line(stdout, line.trim_end().to_string()));
+            }
+        };
+        loop {
+            match pipe.read(&mut buf) {
+                Ok(0) | Err(_) => break,
+                Ok(n) => {
+                    for &b in &buf[..n] {
+                        if b == b'\n' {
+                            flush(&mut pending);
+                        } else if b != b'\r' {
+                            pending.push(b);
+                        }
+                    }
+                }
+            }
+        }
+        flush(&mut pending);
+        let _ = tx.send(Event::Closed);
+    });
+}
+
+fn flush<T>(batch: &mut Vec<T>, on_batch: &mut dyn FnMut(Vec<T>)) {
+    if !batch.is_empty() {
+        on_batch(std::mem::take(batch));
+    }
+}
+
+/// Runs `cmd`, parsing every stdout line with `parse` and handing the results to
+/// `on_batch` — as soon as `max` are ready, or once the oldest waiting line is `idle`
+/// old, so neither a quiet nor a steady stream holds lines back. Stderr is kept as a
+/// tail for the error message. Returns whether the child exited successfully.
+pub(crate) fn stream_batched<T>(
+    mut cmd: Command,
+    cancel: &CancellationToken,
+    idle: Duration,
+    max: usize,
+    mut parse: impl FnMut(&str) -> Option<T>,
+    on_batch: &mut dyn FnMut(Vec<T>),
+) -> IdeResult<(bool, Vec<String>)> {
+    if cancel.is_cancelled() {
+        return Err(IdeError::cancelled());
+    }
+    prepare(&mut cmd);
+    let mut child = spawn(&mut cmd)?;
+    let (tx, rx) = mpsc::channel::<Event>();
+    let mut open = 0;
+    if let Some(out) = child.stdout.take() {
+        spawn_reader(out, tx.clone(), true);
+        open += 1;
+    }
+    if let Some(err) = child.stderr.take() {
+        spawn_reader(err, tx.clone(), false);
+        open += 1;
+    }
+    drop(tx);
+    let mut stderr_tail: Vec<String> = Vec::new();
+    let mut batch: Vec<T> = Vec::with_capacity(max);
+    // When the first line of the waiting batch arrived.
+    let mut since = Instant::now();
+    while open > 0 {
+        if cancel.is_cancelled() {
+            terminate_tree(&mut child, KILL_GRACE);
+            return Err(IdeError::cancelled());
+        }
+        let wait = if batch.is_empty() { idle } else { idle.saturating_sub(since.elapsed()) };
+        match rx.recv_timeout(wait) {
+            Ok(Event::Line(true, line)) => {
+                if let Some(item) = parse(&line) {
+                    if batch.is_empty() {
+                        since = Instant::now();
+                    }
+                    batch.push(item);
+                    if batch.len() >= max || since.elapsed() >= idle {
+                        flush(&mut batch, on_batch);
+                    }
+                }
+            }
+            Ok(Event::Line(false, line)) => {
+                if !line.trim().is_empty() {
+                    stderr_tail.push(line);
+                    if stderr_tail.len() > 20 {
+                        stderr_tail.remove(0);
+                    }
+                }
+            }
+            Ok(Event::Closed) => open -= 1,
+            Err(mpsc::RecvTimeoutError::Timeout) => flush(&mut batch, on_batch),
+            Err(mpsc::RecvTimeoutError::Disconnected) => break,
+        }
+    }
+    flush(&mut batch, on_batch);
+    let status = loop {
+        if let Some(status) = child.try_wait()? {
+            break status;
+        }
+        if cancel.is_cancelled() {
+            terminate_tree(&mut child, KILL_GRACE);
+            return Err(IdeError::cancelled());
+        }
+        std::thread::sleep(Duration::from_millis(10));
+    };
+    Ok((status.success(), stderr_tail))
+}
+
+#[cfg(all(test, unix))]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn a_steady_stream_is_handed_over_while_it_runs() {
+        let mut cmd = Command::new("sh");
+        cmd.args(["-c", "for i in $(seq 1 20); do echo $i; sleep 0.02; done"]);
+        let mut sizes = Vec::new();
+        let (ok, _) = stream_batched(
+            cmd,
+            &CancellationToken::new(),
+            Duration::from_millis(60),
+            300,
+            |line| Some(line.to_owned()),
+            &mut |batch| sizes.push(batch.len()),
+        )
+        .unwrap();
+        assert!(ok);
+        assert_eq!(sizes.iter().sum::<usize>(), 20);
+        assert!(sizes.len() >= 3, "lines arriving every 20 ms waited for the end: {sizes:?}");
+    }
+}
@@ -0,0 +1,65 @@
+//! Drives a real device through `adb`, checking what the Logcat tool window does:
+//! that the device list parses, that the stream delivers batches, and that
+//! cancelling stops both the stream and its `adb` process.
+//!
+//! Ignored by default (needs a connected device). Run with
+//! `OPENIDEA_ADB_DEVICE=<serial> cargo test -p ide-android --test device -- --ignored --nocapture`
+//! — without the variable, the connected device is used when there is exactly one.
+
+use ide_android::*;
+use ide_core::CancellationToken;
+use std::sync::{Arc, Mutex};
+use std::time::{Duration, Instant};
+
+fn serial() -> Option<String> {
+    if let Ok(serial) = std::env::var("OPENIDEA_ADB_DEVICE") {
+        return Some(serial);
+    }
+    let online = devices().ok()?.into_iter().filter(AndroidDevice::is_online).collect::<Vec<_>>();
+    (online.len() == 1).then(|| online[0].serial.clone())
+}
+
+#[test]
+#[ignore]
+fn finds_the_adb_executable() {
+    let adb = adb_executable().expect("adb (set ANDROID_HOME or OPENIDEA_ADB)");
+    println!("adb: {}", adb.display());
+    assert!(adb.is_file());
+}
+
+#[test]
+#[ignore]
+fn lists_connected_devices() {
+    let devices = devices().expect("adb devices");
+    for device in &devices {
+        println!("{:<16} {:<14} {} ({:?})", device.serial, device.state, device.label(), device.transport_id);
+    }
+    assert!(!devices.is_empty(), "no devices connected");
+}
+
+#[test]
+#[ignore]
+fn streams_batches_and_stops_on_cancel() {
+    let serial = serial().expect("a single connected device, or OPENIDEA_ADB_DEVICE");
+    let cancel = CancellationToken::new();
+    let stop = cancel.clone();
+    let received = Arc::new(Mutex::new(Vec::<LogcatLine>::new()));
+    let sink = received.clone();
+    let started = Instant::now();
+    let stream = std::thread::spawn(move || {
+        ide_android::logcat(&serial, false, &stop, &mut |batch| {
+            sink.lock().unwrap().extend(batch);
+        })
+    });
+    // Enough to see the tail seed and a few live lines from a device that idles.
+    std::thread::sleep(Duration::from_secs(4));
+    cancel.cancel();
+    stream.join().unwrap().expect("logcat stops cleanly when cancelled");
+    let lines = received.lock().unwrap();
+    println!("{} lines in {:?}", lines.len(), started.elapsed());
+    for line in lines.iter().rev().take(5) {
+        println!("{:<14} {:>6} {}", line.tag, line.pid, line.message);
+    }
+    assert!(!lines.is_empty(), "no lines within 4s");
+    assert!(lines.iter().any(|l| l.level != LogcatLevel::Unknown), "every line failed to parse");
+}
@@ -8,14 +8,12 @@ license.workspace = true
 [dependencies]
 dunce.workspace = true
 ide-core.workspace = true
+zip.workspace = true
 serde.workspace = true
 serde_json.workspace = true
 specta.workspace = true
 tracing.workspace = true
 dirs.workspace = true

-[target.'cfg(unix)'.dependencies]
-libc = "0.2"
-
 [dev-dependencies]
 tempfile.workspace = true
@@ -40,7 +40,7 @@ pub fn plan(root: &Path, model: &BuildModel, module: &Path, cache: &Path) -> Ide
            kind: "maven",
        });
    }
-    if let Some(g) = &model.gradle
+    if let Some(g) = model.gradle_for_module(root, &module)
        && let Some(p) = g.projects.iter().find(|p| root.join(&p.dir) == module)
    {
        let script = cache.join("resources.init.gradle");
@@ -163,11 +163,11 @@ mod tests {
        assert!(maven.args.contains(&"-Dexpression=project.build.outputDirectory".into()));
        assert_eq!(maven.env["JAVA_HOME"], "/jdk");
        model.maven = None;
-        model.gradle = Some(crate::GradleModel {
+        model.gradle = vec![crate::GradleModel {
            command: "/tools/gradlew".into(),
            projects: vec![crate::GradleProject { path: ":app".into(), dir: "app".into(), ..Default::default() }],
            ..Default::default()
-        });
+        }];
        let gradle = plan(&root, &model, Path::new("app"), &cache).unwrap();
        assert_eq!(gradle.command, "/tools/gradlew");
        assert_eq!(gradle.args.last().unwrap(), ":app:openideaUpdateResources");
@@ -10,6 +10,7 @@ pub use fingerprint::{LaunchFingerprint, launch_fingerprint};

 use crate::process::{self, Stream};
 use crate::{BuildModel, maven};
+use ide_core::settings::CMakeProfile;
 use ide_core::{CancellationToken, Diagnostic, IdeError, IdeResult, Pos, Range, Severity};
 use parse::{ColUnit, Format, OutputParser, RawMessage};
 use serde::{Deserialize, Serialize};
@@ -41,6 +42,8 @@ pub enum BuildSystem {
    Go,
    #[serde(rename = "typescript")]
    TypeScript,
+    #[serde(rename = "cmake")]
+    CMake,
 }

 /// One command of a build.
@@ -144,7 +147,9 @@ fn detect_dir(dir: &Path, model: &BuildModel, root: &Path) -> Option<BuildSystem
    let rel = rel_str(root, dir);
    if model.maven.as_ref().is_some_and(|m| m.projects.iter().any(|p| p.dir == rel)) || has(dir, &["pom.xml"]) {
        Some(BuildSystem::Maven)
-    } else if has(dir, &["build.gradle", "build.gradle.kts", "settings.gradle", "settings.gradle.kts"]) {
+    } else if model.gradle_for_module(root, dir).is_some()
+        || has(dir, &["build.gradle", "build.gradle.kts", "settings.gradle", "settings.gradle.kts"])
+    {
        Some(BuildSystem::Gradle)
    } else if has(dir, &["Cargo.toml"]) {
        Some(BuildSystem::Cargo)
@@ -152,18 +157,20 @@ fn detect_dir(dir: &Path, model: &BuildModel, root: &Path) -> Option<BuildSystem
        Some(BuildSystem::Go)
    } else if has(dir, &["tsconfig.json", "package.json"]) {
        Some(BuildSystem::TypeScript)
+    } else if has(dir, &["CMakeLists.txt"]) {
+        Some(BuildSystem::CMake)
    } else {
        None
    }
 }

-/// `root/rel`, without a trailing separator for the root itself.
+/// Resolves a workspace-relative or absolute directory with native path separators.
 fn subdir(root: &Path, rel: &str) -> PathBuf {
-    if rel.is_empty() { root.to_path_buf() } else { root.join(rel) }
+    root.join(rel).components().collect()
 }

 fn rel_str(root: &Path, dir: &Path) -> String {
-    dir.strip_prefix(root).map(|r| r.to_string_lossy().replace('\\', "/")).unwrap_or_default()
+    dir.strip_prefix(root).unwrap_or(dir).to_string_lossy().replace('\\', "/")
 }

 /// Directories from `file`'s folder up to `root` (inclusive).
@@ -173,11 +180,25 @@ fn ancestors_within<'a>(root: &'a Path, file: &'a Path) -> impl Iterator<Item =
 }

 /// The build of `root`, or of the module containing `file` (Build Module / Recompile).
-pub fn plan(root: &Path, model: &BuildModel, kind: BuildKind, file: Option<&Path>) -> IdeResult<BuildPlan> {
+/// `cmake`: the CMake profiles of the settings (the first one is built), if any.
+pub fn plan(
+    root: &Path,
+    model: &BuildModel,
+    kind: BuildKind,
+    file: Option<&Path>,
+    cmake: Option<&[CMakeProfile]>,
+) -> IdeResult<BuildPlan> {
    let project_name = root.file_name().map_or_else(|| "project".to_owned(), |n| n.to_string_lossy().into_owned());
    let module_dir = match file {
        Some(f) => {
-            let dir = ancestors_within(root, f)
+            let scope = model
+                .gradle
+                .iter()
+                .flat_map(|g| std::iter::once(root.join(&g.dir)).chain(g.projects.iter().map(|p| root.join(&p.dir))))
+                .filter(|dir| f.starts_with(dir))
+                .max_by_key(|dir| dir.components().count())
+                .unwrap_or_else(|| root.to_path_buf());
+            let dir = ancestors_within(&scope, f)
                .find(|d| detect_dir(d, model, root).is_some())
                .ok_or_else(|| IdeError::not_found(format!("{} is not in a module", f.display())))?;
            Some(dir.to_path_buf())
@@ -185,9 +206,13 @@ pub fn plan(root: &Path, model: &BuildModel, kind: BuildKind, file: Option<&Path
        None => None,
    };
    let dir = module_dir.clone().unwrap_or_else(|| root.to_path_buf());
+    // A folder of sibling projects has no build file itself; its Maven projects are built one by one.
    let system = detect_dir(&dir, model, root)
-        .or_else(|| if model.gradle.is_some() { Some(BuildSystem::Gradle) } else { None })
-        .ok_or_else(|| IdeError::not_found("no supported build system (Maven, Gradle, Cargo, Go, TypeScript) found"))?;
+        .or((!model.gradle.is_empty()).then_some(BuildSystem::Gradle))
+        .or_else(|| model.maven.as_ref().filter(|m| !m.projects.is_empty()).map(|_| BuildSystem::Maven))
+        .ok_or_else(|| {
+            IdeError::not_found("no supported build system (Maven, Gradle, Cargo, Go, TypeScript, CMake) found")
+        })?;
    let module = module_dir.as_deref().filter(|d| *d != root);
    let title = match module {
        Some(d) => format!(
@@ -204,6 +229,7 @@ pub fn plan(root: &Path, model: &BuildModel, kind: BuildKind, file: Option<&Path
        // Go builds the file's package (a module holds many).
        BuildSystem::Go => go_steps(file.and_then(Path::parent).unwrap_or(&dir), kind),
        BuildSystem::TypeScript => ts_steps(&dir, kind),
+        BuildSystem::CMake => cmake_steps(&dir, kind, cmake.and_then(<[_]>::first)),
    };
    Ok(BuildPlan { system, title, steps })
 }
@@ -250,14 +276,16 @@ fn maven_steps(root: &Path, model: &BuildModel, kind: BuildKind, module: Option<
 }

 fn gradle_steps(root: &Path, model: &BuildModel, kind: BuildKind, module: Option<&Path>) -> IdeResult<Vec<BuildStep>> {
-    let fallback;
-    let g = match &model.gradle {
-        Some(g) => g,
-        None => {
-            fallback = crate::gradle::load(root).ok_or_else(|| IdeError::not_found("no Gradle build found"))?;
-            &fallback
-        }
-    };
+    if module.is_none() && !model.gradle.is_empty() {
+        return Ok(model.gradle.iter().flat_map(|g| gradle_step(root, g, kind, None)).collect());
+    }
+    let g = module
+        .and_then(|m| model.gradle_for_module(root, m))
+        .ok_or_else(|| IdeError::not_found("module does not belong to a linked Gradle build"))?;
+    Ok(gradle_step(root, g, kind, module))
+}
+
+fn gradle_step(root: &Path, g: &crate::GradleModel, kind: BuildKind, module: Option<&Path>) -> Vec<BuildStep> {
    let prefix = module
        .and_then(|m| {
            let rel = rel_str(root, m);
@@ -276,7 +304,7 @@ fn gradle_steps(root: &Path, model: &BuildModel, kind: BuildKind, module: Option
    let mut s = BuildStep::new(&g.command, &["--console=plain"], &subdir(root, &g.dir), Format::Gradle);
    s.args.extend(tasks);
    s.env = g.env.clone();
-    Ok(vec![s])
+    vec![s]
 }

 fn cargo_steps(dir: &Path, kind: BuildKind) -> Vec<BuildStep> {
@@ -297,6 +325,50 @@ fn cargo_steps(dir: &Path, kind: BuildKind) -> Vec<BuildStep> {
    }
 }

+/// CLion's Build Project for a CMake project: configures the build directory when it has no
+/// `CMakeCache.txt` yet, then `cmake --build` (`--clean-first` to rebuild). The directory and
+/// options come from the CMake profile; without one, a configured directory of the project
+/// (the first by name), else `build`, as the generated run configurations use.
+fn cmake_steps(dir: &Path, kind: BuildKind, profile: Option<&CMakeProfile>) -> Vec<BuildStep> {
+    let build_dir = match profile {
+        Some(p) if !p.build_dir.trim().is_empty() => p.build_dir.trim().to_owned(),
+        Some(p) => format!("cmake-build-{}", p.build_type.to_lowercase()),
+        None => {
+            let mut configured: Vec<String> = std::fs::read_dir(dir)
+                .into_iter()
+                .flatten()
+                .flatten()
+                .filter(|e| e.path().join("CMakeCache.txt").is_file())
+                .map(|e| e.file_name().to_string_lossy().into_owned())
+                .collect();
+            configured.sort();
+            configured.into_iter().next().unwrap_or_else(|| "build".into())
+        }
+    };
+    let build_type = profile.map_or("Debug", |p| p.build_type.as_str());
+    let env = profile.map(|p| p.env.clone()).unwrap_or_default();
+    let mut steps = Vec::new();
+    if !dir.join(&build_dir).join("CMakeCache.txt").is_file() {
+        let mut configure = BuildStep::new("cmake", &["-S", ".", "-B", &build_dir], dir, Format::Gcc);
+        if let Some(p) = profile.filter(|p| !p.generator.trim().is_empty()) {
+            configure.args.extend(["-G".into(), p.generator.clone()]);
+        }
+        configure.args.push(format!("-DCMAKE_BUILD_TYPE={build_type}"));
+        configure.args.push("-DCMAKE_EXPORT_COMPILE_COMMANDS=ON".into());
+        configure.args.extend(profile.map(|p| p.cmake_args.clone()).unwrap_or_default());
+        configure.env = env.clone();
+        steps.push(configure);
+    }
+    let mut build = BuildStep::new("cmake", &["--build", &build_dir, "--config", build_type], dir, Format::Gcc);
+    if kind == BuildKind::Rebuild {
+        build.args.push("--clean-first".into());
+    }
+    build.args.extend(profile.map(|p| p.build_args.clone()).unwrap_or_default());
+    build.env = env;
+    steps.push(build);
+    steps
+}
+
 fn go_steps(dir: &Path, kind: BuildKind) -> Vec<BuildStep> {
    let module_root = dir.ancestors().find(|d| d.join("go.mod").is_file()).unwrap_or(dir);
    let target = if module_root == dir { "./...".to_owned() } else { format!("./{}/...", rel_str(module_root, dir)) };
@@ -682,7 +754,7 @@ fn launch_plan(root: &Path, model: &BuildModel, module: &Path, test: bool) -> Id
    } else {
        BuildKind::Build
    };
-    let mut plan = plan(root, model, kind, Some(module))?;
+    let mut plan = plan(root, model, kind, Some(module), None)?;
    if plan.system == BuildSystem::Maven && !test {
        for step in &mut plan.steps {
            if let Some(goal) = step.args.last_mut() {
@@ -735,11 +807,11 @@ fn launch_class_dirs(system: BuildSystem, module: &Path, test: bool) -> Vec<Path
            .iter()
            .flat_map(|s| {
                ["classes/kotlin", "classes/groovy", "classes/scala", "classes/java", "resources"]
-                    .map(|d| module.join("build").join(d).join(s))
+                    .map(|d| subdir(module, &format!("build/{d}/{s}")))
            })
            .collect(),
-        BuildSystem::Maven if test => vec![module.join("target/test-classes"), module.join("target/classes")],
-        BuildSystem::Maven => vec![module.join("target/classes")],
+        BuildSystem::Maven if test => vec![subdir(module, "target/test-classes"), subdir(module, "target/classes")],
+        BuildSystem::Maven => vec![subdir(module, "target/classes")],
        _ => Vec::new(),
    };
    dirs.into_iter().filter(|d| d.is_dir()).collect()
@@ -747,8 +819,105 @@ fn launch_class_dirs(system: BuildSystem, module: &Path, test: bool) -> Vec<Path

 #[cfg(test)]
 mod tests {
+    #[test]
+    fn independent_gradle_builds_keep_their_launchers_and_task_paths() {
+        let wrapper = if cfg!(windows) { "gradlew.bat" } else { "gradlew" };
+        let temp = tempfile::tempdir().unwrap();
+        let root = temp.path();
+        for dir in ["a", "b"] {
+            std::fs::create_dir_all(root.join(dir).join("app/src/main/java")).unwrap();
+            std::fs::write(root.join(dir).join("settings.gradle"), "include 'app'").unwrap();
+            std::fs::write(root.join(dir).join("app/build.gradle"), "plugins { id 'java' }").unwrap();
+            std::fs::write(root.join(dir).join(wrapper), "").unwrap();
+        }
+        let settings = ide_core::settings::GradleSettings {
+            linked_projects: Some(vec!["a".into(), "b".into()]),
+            ..Default::default()
+        };
+        let mut model = crate::load_linked(root, &root.join("cache"), None, &Default::default(), &settings);
+        model.gradle[0].env.insert("JAVA_HOME".into(), "/jdk-a".into());
+        model.gradle[1].env.insert("JAVA_HOME".into(), "/jdk-b".into());
+        let all = super::plan(root, &model, super::BuildKind::Build, None, None).unwrap();
+        assert_eq!(all.steps.len(), 2);
+        assert_eq!(all.steps[0].cwd, root.join("a"));
+        assert_eq!(all.steps[1].cwd, root.join("b"));
+        let module = super::plan(root, &model, super::BuildKind::Rebuild, Some(&root.join("b/app")), None).unwrap();
+        assert_eq!(module.steps.len(), 1);
+        assert_eq!(module.steps[0].program, root.join("b").join(wrapper).to_string_lossy());
+        assert_eq!(module.steps[0].cwd, root.join("b"));
+        assert_eq!(module.steps[0].env["JAVA_HOME"], "/jdk-b");
+        assert_eq!(module.steps[0].args, ["--console=plain", ":app:clean", ":app:classes", ":app:testClasses"]);
+        // A directly linked build owns its module even when another composite reports it too.
+        let direct = model.gradle[1].projects[0].clone();
+        model.gradle[0].projects.push(direct);
+        assert_eq!(model.gradle_for_module(root, &root.join("b")).unwrap().dir, "b");
+        let mut nested = model.gradle[1].projects[1].clone();
+        nested.path = ":b:app".into();
+        model.gradle[0].projects.push(nested);
+        let nested = super::plan(root, &model, super::BuildKind::Build, Some(&root.join("b/app")), None).unwrap();
+        assert_eq!(nested.steps[0].program, root.join("b").join(wrapper).to_string_lossy());
+        assert_eq!(nested.steps[0].args, ["--console=plain", ":app:classes", ":app:testClasses"]);
+        model.gradle.clear();
+        assert!(super::plan(root, &model, super::BuildKind::Build, Some(&root.join("b/app")), None).is_err());
+    }
+
+    #[test]
+    fn absolute_linked_roots_build_the_project_and_external_source_module() {
+        let wrapper = if cfg!(windows) { "gradlew.bat" } else { "gradlew" };
+        let temp = tempfile::tempdir().unwrap();
+        let base = dunce::canonicalize(temp.path()).unwrap();
+        let root = base.join("workspace");
+        let external = base.join("external");
+        std::fs::create_dir(&root).unwrap();
+        std::fs::create_dir_all(external.join("app/src/main/java")).unwrap();
+        std::fs::write(external.join("settings.gradle"), "include 'app'").unwrap();
+        let source = external.join("app/src/main/java/App.java");
+        std::fs::write(&source, "class App {}").unwrap();
+        std::fs::write(external.join(wrapper), "").unwrap();
+        let settings = ide_core::settings::GradleSettings {
+            linked_projects: Some(vec![external.to_string_lossy().into_owned()]),
+            ..Default::default()
+        };
+        let mut model = crate::load_linked(&root, &base.join("cache"), None, &Default::default(), &settings);
+        model.gradle[0].env.insert("JAVA_HOME".into(), "/external-jdk".into());
+        let all = super::plan(&root, &model, super::BuildKind::Build, None, None).unwrap();
+        assert_eq!(all.steps[0].cwd, external);
+        assert_eq!(all.steps[0].program, external.join(wrapper).to_string_lossy());
+        let module = super::plan(&root, &model, super::BuildKind::Rebuild, Some(&source), None).unwrap();
+        assert_eq!(module.steps[0].cwd, external);
+        assert_eq!(module.steps[0].env["JAVA_HOME"], "/external-jdk");
+        assert_eq!(module.steps[0].args, ["--console=plain", ":app:clean", ":app:classes", ":app:testClasses"]);
+        let other = base.join("unlinked");
+        std::fs::create_dir(&other).unwrap();
+        std::fs::write(other.join("build.gradle"), "").unwrap();
+        assert!(super::plan(&root, &model, super::BuildKind::Build, Some(&other), None).is_err());
+    }
    use super::*;

+    /// Launch outputs use the platform separator throughout, so they compare equal to
+    /// the same directories as JDT LS reports them.
+    #[test]
+    fn launch_dirs_use_one_separator() {
+        let root = tempfile::tempdir().unwrap();
+        let module = subdir(root.path(), "parent/app");
+        for dir in ["target/classes", "target/test-classes", "build/classes/java/main", "build/resources/test"] {
+            std::fs::create_dir_all(subdir(&module, dir)).unwrap();
+        }
+        let foreign = if std::path::MAIN_SEPARATOR == '\\' { '/' } else { '\\' };
+        let dirs = [
+            launch_class_dirs(BuildSystem::Maven, &module, true),
+            launch_class_dirs(BuildSystem::Gradle, &module, true),
+        ]
+        .concat();
+        assert_eq!(dirs.len(), 4, "{dirs:?}");
+        for dir in &dirs {
+            let suffix = dir.strip_prefix(root.path()).unwrap().to_string_lossy().into_owned();
+            assert!(!suffix.contains(foreign), "{suffix}");
+        }
+        assert_eq!(subdir(root.path(), ""), root.path());
+        assert_eq!(subdir(root.path(), "a//b/"), root.path().join("a").join("b"));
+    }
+
    fn write(root: &Path, rel: &str, text: &str) {
        let p = root.join(rel);
        std::fs::create_dir_all(p.parent().unwrap()).unwrap();
@@ -767,12 +936,12 @@ mod tests {
        write(&root, "core/pom.xml", "<project><artifactId>core</artifactId></project>");
        write(&root, "core/src/main/java/A.java", "class A {}");
        let model = crate::load(&root, &tmp.path().join("cache"), None);
-        let p = plan(&root, &model, BuildKind::Build, None).unwrap();
+        let p = plan(&root, &model, BuildKind::Build, None, None).unwrap();
        assert_eq!(p.system, BuildSystem::Maven);
        assert_eq!(p.title, "demo");
        assert_eq!(p.steps.len(), 1);
        assert_eq!(p.steps[0].args, ["-B", "-Dstyle.color=never", "test-compile"]);
-        let p = plan(&root, &model, BuildKind::Rebuild, Some(&root.join("core/src/main/java/A.java"))).unwrap();
+        let p = plan(&root, &model, BuildKind::Rebuild, Some(&root.join("core/src/main/java/A.java")), None).unwrap();
        assert_eq!(p.steps[0].args, ["-B", "-Dstyle.color=never", "-pl", "core", "-am", "clean", "test-compile"]);
        assert_eq!(p.steps[0].cwd, root);
        assert_eq!(p.title, "demo: build module 'core'");
@@ -781,24 +950,24 @@ mod tests {
        write(&g, "settings.gradle", "include 'app'");
        write(&g, "app/build.gradle", "apply plugin: 'java'");
        let model = crate::load(&g, &tmp.path().join("cache2"), None);
-        let p = plan(&g, &model, BuildKind::Build, Some(&g.join("app/src/A.java"))).unwrap();
+        let p = plan(&g, &model, BuildKind::Build, Some(&g.join("app/src/A.java")), None).unwrap();
        assert_eq!(p.system, BuildSystem::Gradle);
        assert_eq!(p.steps[0].args, ["--console=plain", ":app:classes", ":app:testClasses"]);
        assert_eq!(
-            plan(&g, &model, BuildKind::Artifacts, None).unwrap().steps[0].args,
+            plan(&g, &model, BuildKind::Artifacts, None, None).unwrap().steps[0].args,
            ["--console=plain", "assemble"]
        );

        let c = tmp.path().join("c");
        write(&c, "Cargo.toml", "[package]\nname='c'");
-        let p = plan(&c, &BuildModel::default(), BuildKind::Rebuild, None).unwrap();
+        let p = plan(&c, &BuildModel::default(), BuildKind::Rebuild, None, None).unwrap();
        assert_eq!(p.system, BuildSystem::Cargo);
        assert_eq!(p.steps.len(), 2);
        assert_eq!(p.steps[0].args[0], "clean");

        let go = tmp.path().join("go");
        write(&go, "go.mod", "module x");
-        let p = plan(&go, &BuildModel::default(), BuildKind::Build, Some(&go.join("pkg/a/a.go"))).unwrap();
+        let p = plan(&go, &BuildModel::default(), BuildKind::Build, Some(&go.join("pkg/a/a.go")), None).unwrap();
        assert_eq!(p.steps[0].args, ["build", "./pkg/a/..."]);
        assert_eq!(p.steps[0].cwd, go);

@@ -806,17 +975,60 @@ mod tests {
        write(&ts, "package.json", r#"{"scripts":{"build":"vite build"}}"#);
        write(&ts, "tsconfig.json", "{}");
        write(&ts, "pnpm-lock.yaml", "");
-        let p = plan(&ts, &BuildModel::default(), BuildKind::Build, None).unwrap();
+        let p = plan(&ts, &BuildModel::default(), BuildKind::Build, None, None).unwrap();
        assert_eq!(p.steps[0].args, ["--noEmit", "--pretty", "false", "-p", "."]);
-        let p = plan(&ts, &BuildModel::default(), BuildKind::Artifacts, None).unwrap();
+        let p = plan(&ts, &BuildModel::default(), BuildKind::Artifacts, None, None).unwrap();
        assert_eq!(
            (p.steps[0].program.as_str(), p.steps[0].args.as_slice()),
            ("pnpm", &["run".to_owned(), "build".to_owned()][..])
        );

+        let cm = tmp.path().join("cm");
+        write(&cm, "CMakeLists.txt", "project(app)");
+        let args = |p: &BuildPlan| p.steps.iter().map(|s| s.args.join(" ")).collect::<Vec<_>>();
+        let p = plan(&cm, &BuildModel::default(), BuildKind::Build, None, None).unwrap();
+        assert_eq!(p.system, BuildSystem::CMake);
+        assert_eq!(
+            args(&p),
+            [
+                "-S . -B build -DCMAKE_BUILD_TYPE=Debug -DCMAKE_EXPORT_COMPILE_COMMANDS=ON",
+                "--build build --config Debug"
+            ],
+            "an unconfigured project is configured first"
+        );
+        write(&cm, "cmake-build-release/CMakeCache.txt", "");
+        let p = plan(&cm, &BuildModel::default(), BuildKind::Rebuild, None, None).unwrap();
+        assert_eq!(
+            args(&p),
+            ["--build cmake-build-release --config Debug --clean-first"],
+            "a configured directory is reused"
+        );
+        let profile = CMakeProfile {
+            build_type: "Release".into(),
+            generator: "Ninja".into(),
+            build_args: vec!["-j".into(), "8".into()],
+            ..CMakeProfile::default()
+        };
+        let p =
+            plan(&cm, &BuildModel::default(), BuildKind::Build, None, Some(std::slice::from_ref(&profile))).unwrap();
+        assert_eq!(args(&p), ["--build cmake-build-release --config Release -j 8"]);
+        let p = plan(&cm, &BuildModel::default(), BuildKind::Build, None, Some(&[CMakeProfile::default()])).unwrap();
+        assert_eq!(p.steps[0].args[..4], ["-S", ".", "-B", "cmake-build-debug"]);
+
+        let siblings = tmp.path().join("siblings");
+        write(&siblings, "core/pom.xml", "<project><artifactId>core</artifactId></project>");
+        write(&siblings, "system/pom.xml", "<project><artifactId>system</artifactId></project>");
+        let model = crate::load(&siblings, &tmp.path().join("cache3"), None);
+        let p = plan(&siblings, &model, BuildKind::Build, None, None).unwrap();
+        assert_eq!(p.system, BuildSystem::Maven);
+        assert_eq!(
+            p.steps.iter().map(|s| s.cwd.clone()).collect::<Vec<_>>(),
+            [siblings.join("core"), siblings.join("system")]
+        );
+
        let none = tmp.path().join("none");
        std::fs::create_dir_all(&none).unwrap();
-        assert!(plan(&none, &BuildModel::default(), BuildKind::Build, None).is_err());
+        assert!(plan(&none, &BuildModel::default(), BuildKind::Build, None, None).is_err());
    }

    #[test]
@@ -22,6 +22,8 @@ pub(crate) enum Format {
    Tsc,
    /// `go build`: `./a.go:12:5: msg`.
    Go,
+    /// GCC / Clang (through `cmake --build`): `src/a.cpp:12:5: error: msg`.
+    Gcc,
 }

 /// What a printed column counts.
@@ -296,6 +298,17 @@ fn go_line(line: &str) -> Option<RawMessage> {
    (!msg.is_empty()).then(|| RawMessage::new(Severity::Error, msg, ColUnit::Byte).at(path, ln, col))
 }

+/// A GCC / Clang diagnostic line; notes and the context lines after it are left as output.
+fn gcc_line(line: &str) -> Option<RawMessage> {
+    let (path, ln, col, rest) = path_line_col(line)?;
+    let rest = rest.strip_prefix(':')?.trim_start();
+    let (severity, msg) =
+        [("fatal error:", Severity::Error), ("error:", Severity::Error), ("warning:", Severity::Warning)]
+            .into_iter()
+            .find_map(|(prefix, severity)| rest.strip_prefix(prefix).map(|m| (severity, m.trim())))?;
+    (!msg.is_empty()).then(|| RawMessage::new(severity, msg, ColUnit::Byte).at(path, ln, col))
+}
+
 /// rustc's JSON diagnostic (`reason: compiler-message`) → message and its rendered text.
 fn cargo_json(v: &Value) -> Option<(Option<RawMessage>, String)> {
    if v.get("reason")?.as_str()? != "compiler-message" {
@@ -410,6 +423,7 @@ impl OutputParser {
            Format::Gradle => javac_header(&line).or_else(|| kotlin_line(&line)),
            Format::Tsc => tsc_line(&line),
            Format::Go => go_line(&line),
+            Format::Gcc => gcc_line(&line),
            Format::Cargo => None,
        };
        if let Some(msg) = parsed {
@@ -563,6 +577,24 @@ mod tests {
        assert_eq!(out[2].text, "Cannot find name 'foo'.");
    }

+    #[test]
+    fn gcc_errors_and_warnings() {
+        let out = parse(
+            Format::Gcc,
+            "[1/2] Building CXX object CMakeFiles/app.dir/main.cpp.o\n\
+             /p/src/main.cpp:12:5: error: use of undeclared identifier 'foo'\n\
+             \x20  12 |     foo();\n\
+             /p/src/util.h:3:10: warning: unused variable 'x' [-Wunused-variable]\n\
+             /p/src/main.cpp:4:10: fatal error: 'missing.h' file not found\n\
+             /p/src/main.cpp:2:1: note: in file included from here\n",
+        );
+        assert_eq!(out.len(), 3, "{out:?}");
+        assert_eq!(out[0].severity, Severity::Error);
+        assert_eq!(out[0].text, "use of undeclared identifier 'foo'");
+        assert_eq!(out[1].severity, Severity::Warning);
+        assert_eq!(out[2].text, "'missing.h' file not found");
+    }
+
    #[test]
    fn go_errors() {
        let out = parse(
@@ -0,0 +1,40 @@
+// OpenIDEA Gradle sync: prints each project as Gradle evaluated it, one JSON line per project.
+// Read by `ide_build::gradle::parse_reported_projects`. Dependencies are not resolved: the
+// Java language server reads the classpath itself, and resolving is the slow part of an import.
+import groovy.json.JsonOutput
+
+def canon = { File f -> f.canonicalPath }
+// Init scripts also run in included builds and buildSrc, whose projects reuse `:`, `:core`…:
+// the identity path (`:lib:core`, `:buildSrc`) tells them apart and addresses their tasks
+// from the root build. Internal API, hence the fallback.
+def identity = { Project p -> try { p.identityPath.toString() } catch (ignored) { p.path } }
+
+def describe = { Project p ->
+    def m = [path: identity(p), dir: canon(p.projectDir), buildDir: canon(p.layout.buildDirectory.get().asFile)]
+    if (p.gradle.parent != null) m.build = identity(p.rootProject)
+    def sets = p.extensions.findByName('sourceSets')
+    if (sets != null) {
+        // Test source sets as IDEA classifies them: `test`, test fixtures, JVM test suites,
+        // and sets whose folders the `idea` plugin lists as test sources.
+        def suites = [] as Set
+        try { p.extensions.findByName('testing')?.suites?.each { suites << it.sources.name } } catch (ignored) {}
+        def ideaTests = [] as Set
+        try { p.extensions.findByName('idea')?.module?.testSources?.files?.each { ideaTests << canon(it) } } catch (ignored) {}
+        m.sourceSets = sets.collect { s ->
+            def res = s.resources.srcDirs.collect(canon)
+            def src = s.allSource.srcDirs.collect(canon) - res
+            def test = s.name == 'test' || s.name == 'testFixtures' || suites.contains(s.name) ||
+                s.name.endsWith('Test') || s.name.endsWith('Tests') ||
+                (!src.isEmpty() && src.every { ideaTests.contains(it) })
+            [name: s.name, test: test, src: src, res: res]
+        }
+    }
+    try {
+        def java = p.extensions.findByName('java')
+        def lv = java?.toolchain?.languageVersion?.getOrNull()
+        m.java = lv != null ? lv.asInt() : (java?.targetCompatibility?.majorVersion as Integer)
+    } catch (ignored) {}
+    println '@openidea-model\t' + JsonOutput.toJson(m)
+}
+
+gradle.projectsEvaluated { g -> g.rootProject.allprojects { describe(it) } }
@@ -32,7 +32,8 @@ pub struct GradleModel {
 #[derive(Clone, Debug, Default, PartialEq, Serialize, Deserialize, Type)]
 #[serde(rename_all = "camelCase")]
 pub struct GradleProject {
-    /// Gradle path: `:` for the root project, `:app`, `:libs:core`.
+    /// Gradle path: `:` for the root project, `:app`, `:libs:core`; for a project of a
+    /// nested build its identity path (`:lib:core`), which addresses its tasks from the root.
    pub path: String,
    pub name: String,
    /// Project-relative directory.
@@ -40,6 +41,10 @@ pub struct GradleProject {
    /// Project-relative build script, if any.
    pub build_file: Option<String>,
    pub tasks: Vec<GradleTask>,
+    /// Identity path of the nested build holding the project (`:lib` for `includeBuild`,
+    /// `:buildSrc`); null for the opened build.
+    #[serde(default)]
+    pub build: Option<String>,
 }

 #[derive(Clone, Debug, Default, PartialEq, Eq, Serialize, Deserialize, Type)]
@@ -129,35 +134,88 @@ fn include_args(after: &str) -> Vec<String> {
    out
 }

-/// `(root project name, included project paths)` from a settings script.
-pub fn parse_settings(text: &str) -> (Option<String>, Vec<String>) {
+/// What a settings script declares, read statically.
+#[derive(Debug, Default, PartialEq)]
+pub struct Settings {
+    pub name: Option<String>,
+    /// Included project paths (`:app`), in declaration order.
+    pub includes: Vec<String>,
+    /// Project directories that differ from the default `<path>` under the build
+    /// dir, relative to it: `includeFlat` siblings and literal `projectDir = file(..)`.
+    pub dirs: BTreeMap<String, String>,
+}
+
+/// The included projects, root project name and directory overrides of a settings script.
+/// Interpolated (`"$m"`) names and directories cannot be read without Gradle and are skipped.
+pub fn parse_settings(text: &str) -> Settings {
    let text = strip_comments(text);
-    let mut name = None;
-    let mut includes: Vec<String> = Vec::new();
+    let mut s = Settings::default();
    for (i, _) in text.match_indices("rootProject.name") {
        let line = text[i + "rootProject.name".len()..].lines().next().unwrap_or_default();
        if let Some(n) = literals(line).into_iter().next() {
-            name = Some(n);
+            s.name = Some(n);
        }
    }
    let mut from = 0;
    while let Some(i) = text[from..].find("include") {
        let at = from + i;
        from = at + "include".len();
+        let flat = text[from..].starts_with("Flat");
+        if flat {
+            from += "Flat".len();
+        }
        let before_ok = at == 0 || !text[..at].ends_with(|c: char| c.is_alphanumeric() || c == '_' || c == '.');
        let after = &text[from..];
        let after_ok = after.starts_with(|c: char| c == '(' || c.is_whitespace());
        if !before_ok || !after_ok {
            continue;
        }
-        for p in include_args(after) {
+        for p in include_args(after).into_iter().filter(|p| !p.contains('$')) {
            let path = if p.starts_with(':') { p } else { format!(":{p}") };
-            if path.len() > 1 && !includes.contains(&path) {
-                includes.push(path);
+            if path.len() <= 1 {
+                continue;
+            }
+            // `includeFlat 'a'` is the sibling directory `../a` of the root project.
+            if flat {
+                s.dirs.insert(path.clone(), format!("../{}", path.trim_start_matches(':')));
+            }
+            if !s.includes.contains(&path) {
+                s.includes.push(path);
            }
        }
    }
-    (name, includes)
+    // `project(':a').projectDir = file('../a')`; a later assignment wins, as in Gradle.
+    for line in text.lines() {
+        let Some((left, right)) = line.split_once(".projectDir") else { continue };
+        let Some(right) = right.trim_start().strip_prefix('=') else { continue };
+        let Some(arg) = right.trim_start().strip_prefix("file") else { continue };
+        let (Some(path), Some(dir)) = (
+            left.rsplit_once("project").map(|(_, p)| literals(p)).and_then(|l| l.into_iter().next()),
+            literals(arg).into_iter().next(),
+        ) else {
+            continue;
+        };
+        if !path.contains('$') && !dir.contains('$') {
+            let path = if path.starts_with(':') { path } else { format!(":{path}") };
+            s.dirs.insert(path, dir);
+        }
+    }
+    s
+}
+
+/// `a/b/../c` → `a/c`, without touching the filesystem.
+fn normalize(p: &Path) -> PathBuf {
+    let mut out = PathBuf::new();
+    for c in p.components() {
+        match c {
+            std::path::Component::CurDir => {}
+            std::path::Component::ParentDir if out.file_name().is_some() => {
+                out.pop();
+            }
+            c => out.push(c),
+        }
+    }
+    out
 }

 /// The directory of the Gradle build under `root`: the root itself, or a direct
@@ -235,31 +293,170 @@ pub fn default_tasks(is_root: bool, script: &str) -> Vec<GradleTask> {
 }

 /// Reads the Gradle build under `root` (no Gradle run), or `None` when there is none.
+fn read_first(d: &Path, names: &[&str]) -> Option<(String, String)> {
+    names.iter().find_map(|n| std::fs::read_to_string(d.join(n)).ok().map(|t| (n.to_string(), t)))
+}
+
+/// The project `path` in `pdir`, with the default tasks of its build script.
+/// Outside `root` the directory stays absolute (`rel` falls back).
+fn project_at(root: &Path, path: String, name: String, pdir: &Path) -> GradleProject {
+    let script = read_first(pdir, BUILD_FILES);
+    let tasks = default_tasks(path == ":", script.as_ref().map(|(_, t)| t.as_str()).unwrap_or_default());
+    GradleProject {
+        build_file: script.map(|(n, _)| rel(root, &pdir.join(n))),
+        dir: rel(root, pdir),
+        path,
+        name,
+        tasks,
+        build: None,
+    }
+}
+
+/// A project as Gradle evaluated it (the sync's init script, `gradle-model.gradle`).
+#[derive(Clone, Debug, Default, PartialEq, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct ReportedProject {
+    pub path: String,
+    /// Absolute, canonical.
+    pub dir: String,
+    /// Absolute output folder (`layout.buildDirectory`).
+    #[serde(default)]
+    pub build_dir: Option<String>,
+    #[serde(default)]
+    pub source_sets: Vec<ReportedSourceSet>,
+    /// Toolchain language version, else target compatibility.
+    #[serde(default)]
+    pub java: Option<u32>,
+    /// Identity path of the nested build (included build, buildSrc) reporting the project.
+    #[serde(default)]
+    pub build: Option<String>,
+}
+
+#[derive(Clone, Debug, Default, PartialEq, Serialize, Deserialize)]
+pub struct ReportedSourceSet {
+    pub name: String,
+    pub test: bool,
+    /// Absolute source folders (Java, Kotlin, Groovy, …), which need not exist.
+    #[serde(default)]
+    pub src: Vec<String>,
+    /// Absolute resource folders.
+    #[serde(default)]
+    pub res: Vec<String>,
+}
+
+const MODEL_LINE: &str = "@openidea-model\t";
+
+/// The projects printed by `gradle-model.gradle`; malformed lines are skipped.
+pub fn parse_reported_projects(output: &str) -> Vec<ReportedProject> {
+    output.lines().filter_map(|l| serde_json::from_str(l.trim_end().strip_prefix(MODEL_LINE)?).ok()).collect()
+}
+
+/// Source roots of the reported source sets: `(absolute folder, is test, is resources)`.
+pub fn reported_source_roots(reported: &[ReportedProject]) -> Vec<(PathBuf, ReportedRoot)> {
+    let mut out: Vec<(PathBuf, ReportedRoot)> = Vec::new();
+    for p in reported {
+        for set in &p.source_sets {
+            let (src, res) = if set.test {
+                (ReportedRoot::Test, ReportedRoot::TestResources)
+            } else {
+                (ReportedRoot::Source, ReportedRoot::Resources)
+            };
+            for (dir, kind) in set.src.iter().map(|d| (d, src)).chain(set.res.iter().map(|d| (d, res))) {
+                let dir = PathBuf::from(dir);
+                // A folder shared by `main` and another set is `main`'s, as in IDEA.
+                if !out.iter().any(|(d, _)| *d == dir) {
+                    out.push((dir, kind));
+                }
+            }
+        }
+        // IDEA excludes the build folder of every module.
+        if let Some(b) = &p.build_dir {
+            out.push((PathBuf::from(b), ReportedRoot::Excluded));
+        }
+    }
+    out
+}
+
+/// Role of a folder a Gradle sync reported.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum ReportedRoot {
+    Source,
+    Test,
+    Resources,
+    TestResources,
+    Excluded,
+}
+
+/// Replaces the statically read projects with the ones Gradle reported (root first):
+/// settings scripts may compute their projects, which no static reading sees.
+pub fn merge_reported_projects(root: &Path, model: &mut GradleModel, reported: &[ReportedProject]) {
+    if reported.is_empty() {
+        return;
+    }
+    let root_name = model.projects.iter().find(|p| p.path == ":").map(|p| p.name.clone());
+    model.projects = reported
+        .iter()
+        .map(|p| {
+            let name = match p.path.as_str() {
+                ":" => root_name.clone().unwrap_or_default(),
+                path => path.rsplit(':').next().unwrap_or_default().to_owned(),
+            };
+            let mut project = project_at(root, p.path.clone(), name, Path::new(&p.dir));
+            // buildSrc is built before the build, never addressable as `:buildSrc:<task>`.
+            if p.build.as_deref().is_some_and(|b| b.ends_with(":buildSrc")) {
+                project.tasks.clear();
+            }
+            project.build = p.build.clone();
+            project
+        })
+        .collect();
+    // Each build reports its projects when it is evaluated (nested builds first).
+    model.projects.sort_by(|a, b| a.path.cmp(&b.path));
+    // One JDK runs the whole build: the newest any module needs.
+    if let Some(v) = reported.iter().filter_map(|p| p.java).max() {
+        model.java_version = Some(v);
+    }
+}
+
+/// Project directories outside `root`, outermost only (`../svc`, not also `../svc/sources/app`):
+/// the folders IDEA shows as extra top-level module roots.
+pub fn external_roots<'a>(root: &Path, dirs: impl IntoIterator<Item = &'a str>) -> Vec<PathBuf> {
+    let mut dirs: Vec<PathBuf> = dirs.into_iter().map(|d| root.join(d)).filter(|d| !d.starts_with(root)).collect();
+    dirs.sort();
+    dirs.dedup();
+    let mut out: Vec<PathBuf> = Vec::new();
+    for d in dirs {
+        if !out.iter().any(|o| d.starts_with(o)) {
+            out.push(d);
+        }
+    }
+    out
+}
+
 pub fn load(root: &Path) -> Option<GradleModel> {
    let dir = build_dir(root)?;
-    let read = |d: &Path, names: &[&str]| {
-        names.iter().find_map(|n| std::fs::read_to_string(d.join(n)).ok().map(|t| (n.to_string(), t)))
-    };
-    let (name, includes) = read(&dir, SETTINGS_FILES).map(|(_, t)| parse_settings(&t)).unwrap_or_default();
+    load_build(root, dir.strip_prefix(root).unwrap_or(&dir))
+}
+
+/// Loads exactly this build, without searching its child folders.
+pub fn load_build(root: &Path, dir: &Path) -> Option<GradleModel> {
+    // Linked builds are saved with forward slashes; rebuild the path so the launcher
+    // and module folders use the platform's separators.
+    let dir: PathBuf = root.join(dir).components().collect();
+    if !SETTINGS_FILES.iter().chain(BUILD_FILES).any(|name| dir.join(name).is_file()) {
+        return None;
+    }
+    let settings = read_first(&dir, SETTINGS_FILES).map(|(_, t)| parse_settings(&t)).unwrap_or_default();
    let root_name =
-        name.unwrap_or_else(|| dir.file_name().map(|n| n.to_string_lossy().into_owned()).unwrap_or_default());
-    let mut projects = Vec::new();
-    let mut add = |path: String, name: String, pdir: PathBuf| {
-        let script = read(&pdir, BUILD_FILES);
-        let tasks = default_tasks(path == ":", script.as_ref().map(|(_, t)| t.as_str()).unwrap_or_default());
-        projects.push(GradleProject {
-            build_file: script.map(|(n, _)| rel(root, &pdir.join(n))),
-            dir: rel(root, &pdir),
-            path,
-            name,
-            tasks,
-        });
-    };
-    add(":".into(), root_name, dir.clone());
-    for path in includes {
-        let pdir = dir.join(path.trim_start_matches(':').replace(':', "/"));
+        settings.name.unwrap_or_else(|| dir.file_name().map(|n| n.to_string_lossy().into_owned()).unwrap_or_default());
+    let mut projects = vec![project_at(root, ":".into(), root_name, &dir)];
+    for path in settings.includes {
+        let pdir = match settings.dirs.get(&path) {
+            Some(d) => normalize(&dir.join(d)),
+            None => dir.join(path.trim_start_matches(':').replace(':', "/")),
+        };
        let name = path.rsplit(':').next().unwrap_or_default().to_owned();
-        add(path, name, pdir);
+        projects.push(project_at(root, path, name, &pdir));
    }
    let java_version = projects
        .iter()
@@ -269,6 +466,65 @@ pub fn load(root: &Path) -> Option<GradleModel> {
    Some(GradleModel { dir: rel(root, &dir), projects, java_version, command: wrapper(&dir), ..GradleModel::default() })
 }

+/// Validates user-selected build folders and stores a stable, deduplicated identity.
+pub fn normalize_linked_projects(root: &Path, dirs: &[String]) -> ide_core::IdeResult<Vec<String>> {
+    let root = dunce::canonicalize(root)?;
+    let mut out = Vec::new();
+    for dir in dirs {
+        let path = dunce::canonicalize(root.join(dir))?;
+        if !path.is_dir() || !SETTINGS_FILES.iter().chain(BUILD_FILES).any(|name| path.join(name).is_file()) {
+            return Err(ide_core::IdeError::invalid(format!("No Gradle build in {}", path.display())));
+        }
+        let dir = rel(&root, &path);
+        if !out.contains(&dir) {
+            out.push(dir);
+        }
+    }
+    Ok(out)
+}
+
+/// The form `normalize_linked_projects` saves `dir` in, also for a folder that no longer
+/// exists, so a path the UI sends (`C:\…` on Windows) matches the saved entry.
+pub fn linked_project_key(root: &Path, dir: &str) -> String {
+    match (dunce::canonicalize(root), dunce::canonicalize(root.join(dir))) {
+        (Ok(root), Ok(path)) => rel(&root, &path),
+        _ => dir.replace('\\', "/"),
+    }
+}
+
+/// Linked build identities without reading their scripts (also used by index hot paths).
+pub(crate) fn linked_dirs(root: &Path, settings: &ide_core::settings::GradleSettings) -> Vec<String> {
+    match &settings.linked_projects {
+        None => build_dir(root).map(|dir| rel(root, &dir)).into_iter().collect(),
+        Some(dirs) => {
+            let mut out = Vec::new();
+            for dir in dirs {
+                if let Ok(dirs) = normalize_linked_projects(root, std::slice::from_ref(dir)) {
+                    for dir in dirs {
+                        if !out.contains(&dir) {
+                            out.push(dir);
+                        }
+                    }
+                }
+            }
+            out
+        }
+    }
+}
+
+pub fn load_linked(root: &Path, settings: &ide_core::settings::GradleSettings) -> Vec<GradleModel> {
+    linked_dirs(root, settings).iter().filter_map(|dir| load_build(root, Path::new(dir))).collect()
+}
+
+/// A build's task paths are local to it, so sync caches must be local to its identity too.
+pub fn cache_dir(cache: &Path, build_dir: &str) -> PathBuf {
+    if build_dir.is_empty() {
+        return cache.to_path_buf();
+    }
+    let hash = build_dir.bytes().fold(0xcbf29ce484222325u64, |h, b| (h ^ u64::from(b)).wrapping_mul(0x100000001b3));
+    cache.join("gradle").join(format!("{hash:016x}"))
+}
+
 /// `JavaLanguageVersion.of(21)` / `sourceCompatibility = JavaVersion.VERSION_17` in a build script.
 pub fn script_java_version(text: &str) -> Option<u32> {
    let number = |s: &str| -> Option<u32> {
@@ -358,9 +614,32 @@ pub fn build_files(root: &Path, model: &GradleModel) -> Vec<PathBuf> {
    let dir = root.join(&model.dir);
    let mut out: Vec<PathBuf> = SETTINGS_FILES.iter().map(|f| dir.join(f)).filter(|p| p.is_file()).collect();
    out.extend(model.projects.iter().filter_map(|p| p.build_file.as_ref().map(|f| root.join(f))));
+    // The settings of each nested build (its root project's folder).
+    for p in model.projects.iter().filter(|p| p.build.as_deref() == Some(p.path.as_str())) {
+        let nested = root.join(&p.dir);
+        out.extend(SETTINGS_FILES.iter().map(|f| nested.join(f)).filter(|f| f.is_file()));
+    }
+    // What IDEA's auto-import also watches: properties, the wrapper and version catalogs.
+    let extra = ["gradle.properties", "gradle/wrapper/gradle-wrapper.properties"].map(|f| dir.join(f));
+    out.extend(extra.into_iter().filter(|p| p.is_file()));
+    if let Ok(entries) = std::fs::read_dir(dir.join("gradle")) {
+        let mut catalogs: Vec<PathBuf> = entries
+            .flatten()
+            .map(|e| e.path())
+            .filter(|p| p.to_string_lossy().ends_with(".versions.toml") && p.is_file())
+            .collect();
+        catalogs.sort();
+        out.extend(catalogs);
+    }
    out
 }

+/// A build script without comments and with whitespace runs collapsed, so editing a
+/// comment or reformatting does not make a sync stale (IDEA hashes lexer tokens alike).
+pub(crate) fn script_fingerprint(text: &str) -> String {
+    strip_comments(text).split_whitespace().collect::<Vec<_>>().join(" ")
+}
+
 /// `(project path, task)` from `gradle tasks --all` console output; tasks listed as
 /// `app:run` belong to `:app`, unqualified ones to the root project `:`.
 pub fn parse_tasks(output: &str) -> Vec<(String, GradleTask)> {
@@ -407,6 +686,65 @@ pub(crate) fn has_war_plugin(script: &str) -> bool {

 #[cfg(test)]
 mod tests {
+    #[test]
+    fn a_path_from_the_ui_finds_the_saved_link() {
+        let temp = tempfile::tempdir().unwrap();
+        let root = temp.path().join("workspace");
+        let external = temp.path().join("external");
+        for dir in [root.join("a"), external.clone()] {
+            std::fs::create_dir_all(&dir).unwrap();
+            std::fs::write(dir.join("settings.gradle"), "").unwrap();
+        }
+        let native = |p: &std::path::Path| p.to_string_lossy().into_owned();
+        // Saved by linking; unlinking may send a native, absolute or non-canonical spelling.
+        for (dir, sent) in [
+            ("a", native(&root.join("a"))),
+            ("a", "a".to_owned()),
+            ("a", native(&root.join("a").join("..").join("a"))),
+            ("../external", native(&external)),
+        ] {
+            let saved = super::normalize_linked_projects(&root, &[dir.into()]).unwrap();
+            assert_eq!(super::linked_project_key(&root, &sent), saved[0], "{sent}");
+        }
+        // A folder deleted since it was linked still matches its saved entry.
+        assert_eq!(super::linked_project_key(&root, r"gone\build"), "gone/build");
+    }
+
+    #[test]
+    fn explicit_linkage_preserves_default_discovery_and_can_unlink_every_build() {
+        let temp = tempfile::tempdir().unwrap();
+        let root = temp.path();
+        for dir in ["a", "b"] {
+            std::fs::create_dir(root.join(dir)).unwrap();
+            std::fs::write(root.join(dir).join("settings.gradle"), format!("rootProject.name = '{dir}'")).unwrap();
+        }
+        assert_eq!(super::load_linked(root, &Default::default())[0].dir, "a");
+        let mut settings = ide_core::settings::GradleSettings {
+            linked_projects: Some(vec!["b".into(), "./b".into(), "a".into()]),
+            ..Default::default()
+        };
+        let models = super::load_linked(root, &settings);
+        assert_eq!(models.iter().map(|g| g.dir.as_str()).collect::<Vec<_>>(), ["b", "a"]);
+        settings.linked_projects = Some(vec![]);
+        assert!(super::load_linked(root, &settings).is_empty());
+        assert!(super::normalize_linked_projects(root, &["missing".into()]).is_err());
+        assert!(super::normalize_linked_projects(root, &["".into()]).is_err());
+        assert!(super::load_build(root, root).is_none(), "exact loading never picks a child");
+    }
+
+    #[cfg(unix)]
+    #[test]
+    fn linked_directories_deduplicate_symlinks_and_keep_external_builds() {
+        let temp = tempfile::tempdir().unwrap();
+        let root = temp.path().join("workspace");
+        let external = temp.path().join("external");
+        std::fs::create_dir(&root).unwrap();
+        std::fs::create_dir(&external).unwrap();
+        std::fs::write(external.join("build.gradle"), "").unwrap();
+        std::os::unix::fs::symlink(&external, root.join("alias")).unwrap();
+        let dirs = super::normalize_linked_projects(&root, &["alias".into(), "../external".into()]).unwrap();
+        assert_eq!(dirs, [external.canonicalize().unwrap().to_string_lossy().to_string()]);
+    }
    #[test]
    fn script_dependencies_read_string_and_map_notations() {
        let script = r#"
@@ -451,14 +789,60 @@ dependencies {
            /* include("block") */
            includeBuild("plugins")
        "#;
-        let (name, includes) = parse_settings(kts);
-        assert_eq!(name.as_deref(), Some("gradle-demo"));
-        assert_eq!(includes, [":app", ":lib", ":libs:core"]);
+        let s = parse_settings(kts);
+        assert_eq!(s.name.as_deref(), Some("gradle-demo"));
+        assert_eq!(s.includes, [":app", ":lib", ":libs:core"]);
+        assert!(s.dirs.is_empty());

        let groovy = "rootProject.name = 'demo'\ninclude 'a',\n        'b'\ninclude ':c'\nprintln 'x'\n";
-        let (name, includes) = parse_settings(groovy);
-        assert_eq!(name.as_deref(), Some("demo"));
-        assert_eq!(includes, [":a", ":b", ":c"]);
+        let s = parse_settings(groovy);
+        assert_eq!(s.name.as_deref(), Some("demo"));
+        assert_eq!(s.includes, [":a", ":b", ":c"]);
+    }
+
+    #[test]
+    fn settings_include_flat_and_project_dirs() {
+        let groovy = r#"
+            includeFlat 'svc-a'
+            includeFlat 'svc-b', 'svc-c' // trailing comment
+            ['x', 'y'].each { m -> include ":svc-a:$m" }
+            include ':wo'
+            project(':wo').projectDir = file('../svc-a/.worktrees/wo')
+            project(":dyn").projectDir = file("${rootDir}/dyn")
+            includeFlated 'not-a-call'
+        "#;
+        let s = parse_settings(groovy);
+        assert_eq!(s.includes, [":svc-a", ":svc-b", ":svc-c", ":wo"]);
+        assert_eq!(
+            s.dirs.into_iter().collect::<Vec<_>>(),
+            [
+                (":svc-a".into(), "../svc-a".into()),
+                (":svc-b".into(), "../svc-b".into()),
+                (":svc-c".into(), "../svc-c".into()),
+                (":wo".into(), "../svc-a/.worktrees/wo".into()),
+            ]
+        );
+
+        let kts = "includeFlat(\"k\")\nproject(\":k\").projectDir = file(\"../other\")";
+        let s = parse_settings(kts);
+        assert_eq!(s.includes, [":k"]);
+        assert_eq!(s.dirs.get(":k").map(String::as_str), Some("../other"));
+    }
+
+    #[test]
+    fn loads_include_flat_siblings() {
+        let tmp = tempfile::tempdir().unwrap();
+        let ws = tmp.path();
+        std::fs::create_dir_all(ws.join("root")).unwrap();
+        std::fs::create_dir_all(ws.join("svc")).unwrap();
+        std::fs::write(ws.join("root/settings.gradle"), "rootProject.name = 'Root'\nincludeFlat 'svc'").unwrap();
+        std::fs::write(ws.join("svc/build.gradle"), "plugins { id 'java' }").unwrap();
+        let root = ws.join("root");
+        let m = load(&root).unwrap();
+        let svc = m.projects.iter().find(|p| p.path == ":svc").unwrap();
+        assert_eq!(Path::new(&svc.dir), ws.join("svc"));
+        assert_eq!(svc.build_file.as_deref().map(Path::new), Some(ws.join("svc/build.gradle").as_path()));
+        assert!(root.join(svc.build_file.as_ref().unwrap()).is_file());
    }

    #[test]
@@ -539,4 +923,52 @@ Pattern: clean<TaskName>: Cleans the output files of a task.
        let none = tempfile::tempdir().unwrap();
        assert!(load(none.path()).is_none());
    }
+
+    #[test]
+    fn merges_included_builds_and_build_src_by_identity_path() {
+        let tmp = tempfile::tempdir().unwrap();
+        let ws = tmp.path();
+        for d in ["shop/app", "shop/buildSrc", "lib/core"] {
+            std::fs::create_dir_all(ws.join(d)).unwrap();
+        }
+        std::fs::write(ws.join("shop/settings.gradle"), "rootProject.name = 'shop'\ninclude 'app'").unwrap();
+        std::fs::write(ws.join("lib/settings.gradle"), "include 'core'").unwrap();
+        let root = ws.join("shop");
+        // In evaluation order, as the init script prints it: nested builds first.
+        let line = |path: &str, d: &str, build: Option<&str>| {
+            let project = ReportedProject {
+                path: path.into(),
+                dir: ws.join(d).to_string_lossy().into_owned(),
+                build: build.map(Into::into),
+                ..ReportedProject::default()
+            };
+            format!("{MODEL_LINE}{}\n", serde_json::to_string(&project).unwrap())
+        };
+        let out = [
+            line(":lib", "lib", Some(":lib")),
+            line(":lib:core", "lib/core", Some(":lib")),
+            line(":buildSrc", "shop/buildSrc", Some(":buildSrc")),
+            line(":", "shop", None),
+            line(":app", "shop/app", None),
+        ]
+        .concat();
+        let mut model = load(&root).unwrap();
+        merge_reported_projects(&root, &mut model, &parse_reported_projects(&out));
+        let projects: Vec<_> =
+            model.projects.iter().map(|p| (p.path.as_str(), p.name.as_str(), p.build.as_deref())).collect();
+        assert_eq!(
+            projects,
+            [
+                (":", "shop", None),
+                (":app", "app", None),
+                (":buildSrc", "buildSrc", Some(":buildSrc")),
+                (":lib", "lib", Some(":lib")),
+                (":lib:core", "core", Some(":lib")),
+            ]
+        );
+        let build_src = &model.projects[2];
+        assert!(build_src.tasks.is_empty(), "buildSrc tasks cannot run from the root build");
+        assert!(!model.projects[4].tasks.is_empty());
+        assert!(build_files(&root, &model).contains(&ws.join("lib/settings.gradle")));
+    }
 }
@@ -0,0 +1,268 @@
+//! A Gradle project's resolved dependencies for the Dependency Analyzer:
+//! `gradle <project>:dependencies --configuration <name>`, parsed from its tree report.
+
+use crate::gradle;
+use crate::process;
+use crate::sync::{SyncOptions, error_summary};
+use ide_core::{CancellationToken, IdeError, IdeResult};
+use serde::{Deserialize, Serialize};
+use specta::Type;
+use std::path::Path;
+
+/// One line of the report: an occurrence of a dependency where it is requested.
+#[derive(Clone, Debug, Default, PartialEq, Eq, Serialize, Deserialize, Type)]
+#[serde(rename_all = "camelCase")]
+pub struct GradleDependency {
+    /// `group`, empty for a project dependency.
+    pub group: String,
+    /// Artifact name, or the project path (`:core`) of a project dependency.
+    pub name: String,
+    /// The version asked for here; `None` when a platform or constraint supplies it.
+    pub requested: Option<String>,
+    /// The version Gradle selected (`-> 1.2`), when it differs from the request.
+    pub selected: Option<String>,
+    /// A project of the build (`project :core`, or a module substituted by one).
+    pub project: bool,
+    /// `(*)`: listed with its dependencies earlier in the tree.
+    pub repeated: bool,
+    /// `(c)`: a dependency constraint rather than a dependency.
+    pub constraint: bool,
+    /// `(n)` / `FAILED`: not resolved.
+    pub unresolved: bool,
+    pub children: Vec<GradleDependency>,
+}
+
+/// Parses the tree of a `dependencies --configuration` report (lines `+--- g:a:1.0 -> 1.1 (*)`).
+pub fn parse_report(output: &str) -> Vec<GradleDependency> {
+    let mut roots: Vec<GradleDependency> = Vec::new();
+    // Path of child indexes from the roots to the last node of each depth.
+    let mut path: Vec<usize> = Vec::new();
+    for line in output.lines() {
+        let Some((depth, text)) = tree_line(line) else { continue };
+        let node = parse_entry(text);
+        path.truncate(depth);
+        if depth > path.len() {
+            continue; // A line deeper than its parent allows: not part of a well-formed tree.
+        }
+        let siblings = if depth == 0 {
+            &mut roots
+        } else {
+            let mut list = &mut roots;
+            for &i in &path[..depth - 1] {
+                list = &mut list[i].children;
+            }
+            let Some(parent) = list.get_mut(path[depth - 1]) else { continue };
+            &mut parent.children
+        };
+        siblings.push(node);
+        path.push(siblings.len() - 1);
+    }
+    roots
+}
+
+/// `|    \--- g:a:1.0` → (1, "g:a:1.0").
+fn tree_line(line: &str) -> Option<(usize, &str)> {
+    let mut rest = line;
+    let mut depth = 0;
+    loop {
+        if let Some(r) = rest.strip_prefix("+--- ").or_else(|| rest.strip_prefix("\\--- ")) {
+            return Some((depth, r.trim()));
+        }
+        rest = rest.strip_prefix("|    ").or_else(|| rest.strip_prefix("     "))?;
+        depth += 1;
+    }
+}
+
+fn parse_entry(text: &str) -> GradleDependency {
+    let mut d = GradleDependency::default();
+    let mut text = text.trim();
+    loop {
+        if let Some(t) = text.strip_suffix(" (*)") {
+            d.repeated = true;
+            text = t;
+        } else if let Some(t) = text.strip_suffix(" (c)") {
+            d.constraint = true;
+            text = t;
+        } else if let Some(t) = text.strip_suffix(" (n)").or_else(|| text.strip_suffix(" FAILED")) {
+            d.unresolved = true;
+            text = t;
+        } else {
+            break;
+        }
+        text = text.trim_end();
+    }
+    let (left, right) = match text.split_once(" -> ") {
+        Some((l, r)) => (l.trim(), Some(r.trim())),
+        None => (text, None),
+    };
+    if let Some(project) = left.strip_prefix("project ") {
+        d.project = true;
+        d.name = project_path(project);
+    } else {
+        let mut parts = left.splitn(3, ':');
+        d.group = parts.next().unwrap_or_default().to_owned();
+        d.name = parts.next().unwrap_or_default().to_owned();
+        d.requested = parts.next().filter(|v| !v.is_empty()).map(str::to_owned);
+    }
+    if let Some(right) = right {
+        if let Some(project) = right.strip_prefix("project ") {
+            // A module substituted by a project of the build.
+            d.project = true;
+            d.selected = Some(project_path(project));
+        } else {
+            d.selected = Some(right.to_owned());
+        }
+    }
+    d
+}
+
+/// `:core`, or `':core'` as Gradle 9 quotes it.
+fn project_path(text: &str) -> String {
+    let t = text.trim();
+    t.strip_prefix('\'').and_then(|t| t.strip_suffix('\'')).unwrap_or(t).to_owned()
+}
+
+/// Runs the `dependencies` report of `project` (a Gradle path, `:` for the root) for
+/// `configuration` and returns its tree.
+pub fn gradle_dependencies(
+    root: &Path,
+    model: &gradle::GradleModel,
+    options: &SyncOptions,
+    project: &str,
+    configuration: &str,
+    cancel: &CancellationToken,
+) -> IdeResult<Vec<GradleDependency>> {
+    if !configuration.chars().all(|c| c.is_ascii_alphanumeric() || c == '_' || c == '-') || configuration.is_empty() {
+        return Err(IdeError::invalid(format!("not a configuration name: {configuration}")));
+    }
+    if !project.starts_with(':') || project.chars().any(char::is_whitespace) {
+        return Err(IdeError::invalid(format!("not a Gradle project path: {project}")));
+    }
+    let task = if project == ":" { ":dependencies".to_owned() } else { format!("{project}:dependencies") };
+    let mut args: Vec<String> =
+        vec!["--console=plain".into(), "-q".into(), task, "--configuration".into(), configuration.into()];
+    if options.offline {
+        args.push("--offline".into());
+    }
+    let out = process::run(
+        options.gradle_command.as_deref().unwrap_or(&model.command),
+        &args,
+        &root.join(&model.dir),
+        &options.env,
+        cancel,
+        |_, _| {},
+    )?;
+    if !out.success {
+        return Err(IdeError::unavailable(error_summary(&out.text)));
+    }
+    Ok(parse_report(&out.text))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn dep(group: &str, name: &str, requested: Option<&str>) -> GradleDependency {
+        GradleDependency {
+            group: group.into(),
+            name: name.into(),
+            requested: requested.map(Into::into),
+            ..Default::default()
+        }
+    }
+
+    #[test]
+    fn parses_the_tree_with_selected_versions_and_markers() {
+        let report = "\
+------------------------------------------------------------
+Project ':app'
+------------------------------------------------------------
+
+runtimeClasspath - Runtime classpath of source set 'main'.
+--- org.springframework.boot:spring-boot-starter-web -> 3.2.0
+|    +--- org.springframework.boot:spring-boot-starter:3.2.0
+|    |    \\--- org.yaml:snakeyaml:2.2
+|    \\--- com.fasterxml.jackson.core:jackson-databind:2.15.0 -> 2.15.3 (*)
+--- project ':core'
+|    \\--- com.google.guava:guava:{strictly 32.1.3-jre} -> 32.1.3-jre (c)
+--- org.example:legacy:1.0 -> project :legacy
+\\--- org.missing:gone:9 FAILED
+
+(c) - A dependency constraint, not a dependency. The dependency affected by the constraint occurs elsewhere in the tree.
+(*) - Indicates repeated occurrences of a transitive dependency subtree. Gradle expands transitive dependency subtrees only once per project; repeat occurrences only display the root of the subtree, followed by this annotation.
+";
+        let tree = parse_report(report);
+        assert_eq!(tree.len(), 4);
+        let web = &tree[0];
+        assert_eq!((web.group.as_str(), web.name.as_str()), ("org.springframework.boot", "spring-boot-starter-web"));
+        assert_eq!((web.requested.as_deref(), web.selected.as_deref()), (None, Some("3.2.0")));
+        assert_eq!(web.children.len(), 2);
+        assert_eq!(web.children[0].children, vec![dep("org.yaml", "snakeyaml", Some("2.2"))]);
+        let databind = &web.children[1];
+        assert_eq!((databind.requested.as_deref(), databind.selected.as_deref()), (Some("2.15.0"), Some("2.15.3")));
+        assert!(databind.repeated);
+        let core = &tree[1];
+        assert!(core.project && core.group.is_empty());
+        assert_eq!(core.name, ":core");
+        let guava = &core.children[0];
+        assert!(guava.constraint);
+        assert_eq!(guava.requested.as_deref(), Some("{strictly 32.1.3-jre}"));
+        let legacy = &tree[2];
+        assert!(legacy.project);
+        assert_eq!((legacy.name.as_str(), legacy.selected.as_deref()), ("legacy", Some(":legacy")));
+        assert!(tree[3].unresolved);
+        assert_eq!(tree[3].requested.as_deref(), Some("9"));
+    }
+
+    #[test]
+    fn an_empty_configuration_has_no_dependencies() {
+        assert!(
+            parse_report("compileClasspath - Compile classpath for source set 'main'.\nNo dependencies\n").is_empty()
+        );
+    }
+
+    #[test]
+    fn rejects_names_that_are_not_configurations_or_projects() {
+        let tmp = tempfile::tempdir().unwrap();
+        let options = SyncOptions::default();
+        let cancel = CancellationToken::new();
+        assert!(
+            gradle_dependencies(tmp.path(), &Default::default(), &options, ":", "x --init-script y", &cancel).is_err()
+        );
+        assert!(
+            gradle_dependencies(tmp.path(), &Default::default(), &options, "app", "runtimeClasspath", &cancel).is_err()
+        );
+    }
+
+    #[cfg(unix)]
+    #[test]
+    fn runs_the_report_of_the_project_and_configuration() {
+        use std::os::unix::fs::PermissionsExt;
+        let tmp = tempfile::tempdir().unwrap();
+        let root = tmp.path();
+        std::fs::write(root.join("settings.gradle"), "include 'app'").unwrap();
+        std::fs::write(root.join("build.gradle"), "").unwrap();
+        let launcher = root.join("fake-gradle");
+        std::fs::write(&launcher, "#!/bin/sh\necho \"$@\" > args\necho '\\--- org.a:b:1.0'\n").unwrap();
+        std::fs::set_permissions(&launcher, std::fs::Permissions::from_mode(0o755)).unwrap();
+        let options = SyncOptions {
+            gradle_command: Some(launcher.to_string_lossy().into_owned()),
+            offline: true,
+            ..Default::default()
+        };
+        let tree = gradle_dependencies(
+            root,
+            &gradle::load(root).unwrap(),
+            &options,
+            ":app",
+            "testRuntimeClasspath",
+            &CancellationToken::new(),
+        )
+        .unwrap();
+        assert_eq!(tree, vec![dep("org.a", "b", Some("1.0"))]);
+        assert_eq!(
+            std::fs::read_to_string(root.join("args")).unwrap().trim(),
+            "--console=plain -q :app:dependencies --configuration testRuntimeClasspath --offline"
+        );
+    }
+}
@@ -81,7 +81,7 @@ pub fn build(
    cancel: &CancellationToken,
 ) -> IdeResult<Outcome> {
    std::fs::create_dir_all(generation)?;
-    let mut plan = compile::plan(root, model, BuildKind::Build, None)?;
+    let mut plan = compile::plan(root, model, BuildKind::Build, None, None)?;
    if plan.system != compile::BuildSystem::Maven {
        return Err(IdeError::invalid("Kotlin bridge requires a Maven build root"));
    }
@@ -8,6 +8,7 @@
 pub mod application_update;
 pub mod compile;
 pub mod gradle;
+mod gradle_deps;
 pub mod kotlin_bridge;
 pub mod maven;
 pub mod pom_edit;
@@ -17,8 +18,11 @@ pub mod web;
 mod xml;

 pub use gradle::{GradleModel, GradleProject, GradleTask};
+pub use gradle_deps::{GradleDependency, gradle_dependencies};
 pub use maven::{MavenDependency, MavenModel, MavenPlugin, MavenProfile, MavenProject, Omission};
-pub use sync::{SyncOptions, SyncProgress, sync_gradle, sync_maven};
+pub use sync::{
+    SyncOptions, SyncProgress, maven_profiles, save_maven_profiles, sync_gradle, sync_gradle_model, sync_maven,
+};

 use serde::{Deserialize, Serialize};
 use specta::Type;
@@ -36,13 +40,31 @@ pub enum BuildTool {
 #[serde(rename_all = "camelCase")]
 pub struct BuildModel {
    pub maven: Option<MavenModel>,
-    pub gradle: Option<GradleModel>,
+    #[serde(default)]
+    pub gradle: Vec<GradleModel>,
+}
+
+impl BuildModel {
+    /// Prefer the deepest linked build owning the module over a composite including it.
+    pub fn gradle_for_module(&self, root: &Path, module: &Path) -> Option<&GradleModel> {
+        let module = root.join(module);
+        self.gradle.iter().filter(|g| g.projects.iter().any(|p| root.join(&p.dir) == module)).min_by_key(|g| {
+            let dir = root.join(&g.dir);
+            std::cmp::Reverse(if module.starts_with(&dir) { dir.components().count() } else { 0 })
+        })
+    }
 }

 /// Static model of the builds under `root`, merged with the sync results cached in `cache_dir`.
 /// Parent POMs are looked up in `maven_repo` (the configured local repository), else the default one.
 pub fn load(root: &Path, cache_dir: &Path, maven_repo: Option<PathBuf>) -> BuildModel {
-    load_linked(root, cache_dir, maven_repo, &ide_core::settings::MavenSettings::default())
+    load_linked(
+        root,
+        cache_dir,
+        maven_repo,
+        &ide_core::settings::MavenSettings::default(),
+        &ide_core::settings::GradleSettings::default(),
+    )
 }

 /// Loads only linked Maven reactors, retaining an empty model so projects can be re-added.
@@ -51,20 +73,68 @@ pub fn load_linked(
    cache_dir: &Path,
    maven_repo: Option<PathBuf>,
    settings: &ide_core::settings::MavenSettings,
+    gradle_settings: &ide_core::settings::GradleSettings,
 ) -> BuildModel {
-    let maven = maven::is_maven_project(root).then(|| {
-        let mut m = maven::load_with_repo(root, maven_repo.or_else(maven::default_local_repo));
+    let maven = maven::has_projects(root, settings).then(|| {
+        let profiles = sync::maven_profiles(cache_dir);
+        let repo = maven_repo.or_else(maven::default_local_repo);
+        let mut m = maven::load_with_linked(root, repo, &profiles, &settings.linked_projects);
        maven::UnlinkedProjects::from_model(&m, settings).filter(&mut m);
+        // The user settings' profiles can be chosen too (`-P` applies to them as well).
+        for p in maven::user_settings_file(root, settings).map(|f| maven::settings_profiles(&f)).unwrap_or_default() {
+            if !m.profiles.iter().any(|x| x.id == p.id) {
+                m.profiles.push(p);
+            }
+        }
        sync::apply_maven_cache(root, cache_dir, &mut m);
        m
    });
-    let gradle = gradle::load(root).map(|mut g| {
-        sync::apply_gradle_cache(root, cache_dir, &mut g);
-        g
-    });
+    let gradle = gradle::load_linked(root, gradle_settings)
+        .into_iter()
+        .map(|mut g| {
+            sync::apply_gradle_cache(root, &gradle::cache_dir(cache_dir, &g.dir), &mut g);
+            g
+        })
+        .collect();
    BuildModel { maven, gradle }
 }

+/// Gradle project folders outside `root` as of the last sync (`includeFlat` siblings):
+/// extra content roots, as IDEA lists module roots beside the project folder.
+/// Reads only the sync's cached projects (no build script), so it is cheap enough for hot paths.
+pub fn gradle_external_roots(
+    root: &Path,
+    cache_dir: &Path,
+    settings: &ide_core::settings::GradleSettings,
+) -> Vec<PathBuf> {
+    let builds = gradle::linked_dirs(root, settings);
+    let dirs: Vec<String> = builds
+        .iter()
+        .flat_map(|dir| {
+            std::iter::once(root.join(dir).to_string_lossy().into_owned()).chain(
+                sync::reported_gradle_projects(&gradle::cache_dir(cache_dir, dir))
+                    .iter()
+                    .map(|p| p.dir.clone())
+                    .collect::<Vec<_>>(),
+            )
+        })
+        .collect();
+    gradle::external_roots(root, dirs.iter().map(String::as_str))
+}
+
+/// Source, resource and build folders of the last Gradle sync, absolute.
+pub fn gradle_source_roots(
+    root: &Path,
+    cache_dir: &Path,
+    settings: &ide_core::settings::GradleSettings,
+) -> Vec<(PathBuf, gradle::ReportedRoot)> {
+    let reported = gradle::linked_dirs(root, settings)
+        .iter()
+        .flat_map(|dir| sync::reported_gradle_projects(&gradle::cache_dir(cache_dir, dir)).as_ref().clone())
+        .collect::<Vec<_>>();
+    gradle::reported_source_roots(&reported)
+}
+
 /// A library the project depends on, as `groupId:artifactId:version`.
 #[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub struct DependencyCoordinate {
@@ -106,7 +176,7 @@ pub fn dependency_coordinates(root: &Path, model: &BuildModel) -> Vec<Dependency
            });
        }
    }
-    if let Some(g) = &model.gradle {
+    for g in &model.gradle {
        for script in g.projects.iter().filter_map(|p| p.build_file.as_ref()) {
            let Ok(text) = std::fs::read_to_string(root.join(script)) else { continue };
            out.extend(gradle::script_dependencies(&text).into_iter().map(|(group_id, artifact_id, version)| {
@@ -132,6 +202,26 @@ pub fn affects_build(rel: &Path) -> bool {
 mod tests {
    use super::*;

+    #[test]
+    fn external_linked_build_is_indexed_before_sync_and_disappears_when_unlinked() {
+        let temp = tempfile::tempdir().unwrap();
+        let root = temp.path().join("workspace");
+        let external = temp.path().join("external");
+        std::fs::create_dir(&root).unwrap();
+        std::fs::create_dir(&external).unwrap();
+        std::fs::write(external.join("settings.gradle"), "").unwrap();
+        let mut settings = ide_core::settings::GradleSettings {
+            linked_projects: Some(vec![external.to_string_lossy().into_owned()]),
+            ..Default::default()
+        };
+        assert_eq!(
+            gradle_external_roots(&root, &temp.path().join("cache"), &settings),
+            [dunce::canonicalize(&external).unwrap()]
+        );
+        settings.linked_projects = Some(vec![]);
+        assert!(gradle_external_roots(&root, &temp.path().join("cache"), &settings).is_empty());
+    }
+
    #[test]
    fn detects_build_systems_and_build_files() {
        let tmp = tempfile::tempdir().unwrap();
@@ -143,7 +233,7 @@ mod tests {
        std::fs::write(root.join("build.gradle"), "").unwrap();
        let m = load(&root, &cache, None);
        assert_eq!(m.maven.unwrap().projects[0].pom, "svc/pom.xml");
-        assert_eq!(m.gradle.unwrap().projects[0].path, ":");
+        assert_eq!(m.gradle[0].projects[0].path, ":");
        assert!(affects_build(Path::new("a/pom.xml")) && affects_build(Path::new("settings.gradle.kts")));
        assert!(!affects_build(Path::new("src/Main.java")));
    }
@@ -190,7 +280,7 @@ mod tests {
            ],
            ..Default::default()
        };
-        let gradle = gradle::load(root);
+        let gradle = gradle::load(root).into_iter().collect();
        let model = BuildModel { maven: Some(maven), gradle };
        let names: Vec<String> = dependency_coordinates(root, &model)
            .into_iter()
@@ -11,7 +11,9 @@ use crate::xml::{self, Element};
 use serde::{Deserialize, Serialize};
 use specta::Type;
 use std::collections::{BTreeMap, HashMap, HashSet};
+use std::io::Read;
 use std::path::{Path, PathBuf};
+use std::sync::{Mutex, OnceLock};

 /// Phases shown under "Lifecycle" (IDEA's default list).
 pub const LIFECYCLE: &[&str] =
@@ -243,7 +245,8 @@ struct RawPom {
    plugins: Vec<RawPlugin>,
    managed_plugins: Vec<RawPlugin>,
    profiles: Vec<RawProfile>,
-    /// `<build><plugins>` `maven-compiler-plugin` `<release>` / `<source>`.
+    /// `maven-compiler-plugin` `<release>` / `<source>` of `<build><plugins>`, else of
+    /// `<pluginManagement>`.
    compiler_release: Option<String>,
 }

@@ -285,11 +288,29 @@ fn texts(e: &Element, path: &str, item: &str) -> Vec<String> {
    e.list(path, item).iter().map(|m| m.text.trim().to_owned()).filter(|m| !m.is_empty()).collect()
 }

+/// Child modules of a project or profile: `<modules>` (model 4.0.0) plus `<subprojects>`,
+/// which Maven 4 (model 4.1.0) uses instead.
+fn module_names(e: &Element) -> Vec<String> {
+    let mut names = texts(e, "modules", "module");
+    names.extend(texts(e, "subprojects", "subproject"));
+    names
+}
+
 fn read_build(e: &Element, plugins: &mut Vec<RawPlugin>, managed: &mut Vec<RawPlugin>) {
    plugins.extend(e.list("build/plugins", "plugin").into_iter().filter_map(read_plugin));
    managed.extend(e.list("build/pluginManagement/plugins", "plugin").into_iter().filter_map(read_plugin));
 }

+/// `maven-compiler-plugin` `<release>` / `<source>` among the plugins at `path`.
+fn compiler_level(project: &Element, path: &str) -> Option<String> {
+    project
+        .list(path, "plugin")
+        .into_iter()
+        .find(|p| p.text_of("artifactId").as_deref() == Some("maven-compiler-plugin"))
+        .and_then(|p| p.child("configuration"))
+        .and_then(|c| c.text_of("release").or_else(|| c.text_of("source")))
+}
+
 fn read_raw(project: &Element) -> RawPom {
    let parent = project.child("parent").and_then(|p| {
        Some(ParentRef {
@@ -308,7 +329,7 @@ fn read_raw(project: &Element) -> RawPom {
        name: project.text_of("name"),
        parent,
        properties: read_properties(project.child("properties")),
-        modules: texts(project, "modules", "module"),
+        modules: module_names(project),
        deps: project.list("dependencies", "dependency").into_iter().filter_map(read_dep).collect(),
        managed: project
            .list("dependencyManagement/dependencies", "dependency")
@@ -318,18 +339,13 @@ fn read_raw(project: &Element) -> RawPom {
        ..RawPom::default()
    };
    read_build(project, &mut pom.plugins, &mut pom.managed_plugins);
-    if let Some(c) = pom.plugins.iter().position(|p| p.artifact_id == "maven-compiler-plugin") {
-        let plugin =
-            project.list("build/plugins", "plugin").into_iter().filter(|p| p.text_of("artifactId").is_some()).nth(c);
-        if let Some(cfg) = plugin.and_then(|p| p.child("configuration")) {
-            pom.compiler_release = cfg.text_of("release").or_else(|| cfg.text_of("source"));
-        }
-    }
+    pom.compiler_release =
+        compiler_level(project, "build/plugins").or_else(|| compiler_level(project, "build/pluginManagement/plugins"));
    for p in project.list("profiles", "profile") {
        let mut profile = RawProfile {
            id: p.text_of("id").unwrap_or_else(|| "default".into()),
            active_by_default: p.at("activation/activeByDefault").is_some_and(|a| a.text.trim() == "true"),
-            modules: texts(p, "modules", "module"),
+            modules: module_names(p),
            properties: read_properties(p.child("properties")),
            deps: p.list("dependencies", "dependency").into_iter().filter_map(read_dep).collect(),
            ..RawProfile::default()
@@ -401,6 +417,9 @@ struct Inherited {
    managed: Vec<RawDep>,
    plugins: Vec<RawPlugin>,
    managed_plugins: Vec<RawPlugin>,
+    /// The nearest `maven-compiler-plugin` `<release>` / `<source>`: a module usually
+    /// inherits its compiler level from the parent's (managed) plugin configuration.
+    compiler_release: Option<String>,
    /// `<id>`, `activeByDefault`: profiles of the POM and its ancestors —
    /// Maven lets a child enable a parent's profiles with `-P`.
    profiles: Vec<(String, bool)>,
@@ -441,6 +460,8 @@ const MAX_PARENT_DEPTH: usize = 10;

 struct Resolver {
    local_repo: Option<PathBuf>,
+    /// The chosen profiles (`-P` entries; `!id` / `-id` deactivates).
+    profiles: Vec<String>,
    poms: HashMap<PathBuf, Option<RawPom>>,
    contexts: HashMap<PathBuf, Inherited>,
 }
@@ -448,18 +469,68 @@ struct Resolver {
 /// `~/.m2/repository`, or `<localRepository>` from `~/.m2/settings.xml`.
 pub(crate) fn default_local_repo() -> Option<PathBuf> {
    let m2 = dirs::home_dir()?.join(".m2");
-    if let Some(settings) = std::fs::read_to_string(m2.join("settings.xml")).ok().and_then(|t| xml::parse(&t))
-        && let Some(repo) = settings.text_of("localRepository")
-    {
-        let home = dirs::home_dir().map(|h| h.to_string_lossy().into_owned()).unwrap_or_default();
-        return Some(PathBuf::from(repo.replace("${user.home}", &home)));
+    local_repository_of(&m2.join("settings.xml")).or(Some(m2.join("repository")))
+}
+
+/// The user `settings.xml` a build reads: the configured one (`~/` and project-relative
+/// paths allowed), else `~/.m2/settings.xml`.
+pub fn user_settings_file(root: &Path, settings: &ide_core::settings::MavenSettings) -> Option<PathBuf> {
+    let configured = settings.user_settings.trim();
+    if configured.is_empty() {
+        return Some(dirs::home_dir()?.join(".m2").join("settings.xml"));
    }
-    Some(m2.join("repository"))
+    let path = match configured.strip_prefix("~/") {
+        Some(rest) => dirs::home_dir()?.join(rest),
+        None => PathBuf::from(configured),
+    };
+    Some(if path.is_absolute() { path } else { root.join(path) })
+}
+
+/// The profiles a `settings.xml` defines, for the Profiles list beside the POMs' own (as
+/// IDEA lists them): checked by default when `<activeProfiles>` names them or they are
+/// `activeByDefault`.
+pub fn settings_profiles(settings: &Path) -> Vec<MavenProfile> {
+    let Some(root) = std::fs::read_to_string(settings).ok().and_then(|text| xml::parse(&text)) else {
+        return Vec::new();
+    };
+    let active: Vec<String> =
+        root.list("activeProfiles", "activeProfile").iter().map(|e| e.text.trim().to_owned()).collect();
+    let mut profiles: Vec<MavenProfile> = Vec::new();
+    for profile in root.list("profiles", "profile") {
+        let Some(id) = profile.text_of("id") else { continue };
+        if profiles.iter().any(|p| p.id == id) {
+            continue;
+        }
+        let by_default = profile.at("activation/activeByDefault").is_some_and(|e| e.text.trim() == "true");
+        profiles.push(MavenProfile { active_by_default: by_default || active.contains(&id), id });
+    }
+    profiles
+}
+
+/// `<localRepository>` of a settings file, when it names one: the repository a build
+/// with `-s <file>` resolves into, which is not necessarily the user's default.
+pub fn local_repository_of(settings: &Path) -> Option<PathBuf> {
+    let text = std::fs::read_to_string(settings).ok()?;
+    let root = xml::parse(&text)?;
+    let repo = root.text_of("localRepository")?.trim().to_owned();
+    if repo.is_empty() {
+        return None;
+    }
+    let home = dirs::home_dir().map(|h| h.to_string_lossy().into_owned()).unwrap_or_default();
+    Some(PathBuf::from(repo.replace("${user.home}", &home)))
 }

 impl Resolver {
-    fn new(local_repo: Option<PathBuf>) -> Self {
-        Self { local_repo, poms: HashMap::new(), contexts: HashMap::new() }
+    fn new(local_repo: Option<PathBuf>, profiles: &[String]) -> Self {
+        Self { local_repo, profiles: profiles.to_vec(), poms: HashMap::new(), contexts: HashMap::new() }
+    }
+
+    /// The active profiles of a POM: the chosen ones, and the `activeByDefault` ones not turned
+    /// off while none of the POM's other profiles is chosen (Maven's rule).
+    fn active<'a>(&self, profiles: &'a [RawProfile]) -> impl Iterator<Item = &'a RawProfile> {
+        let chosen = |id: &str| profile_choice(&self.profiles, id);
+        let any_chosen = profiles.iter().any(|p| chosen(&p.id) == Some(true));
+        profiles.iter().filter(move |p| chosen(&p.id).unwrap_or(p.active_by_default && !any_chosen))
    }

    fn pom(&mut self, path: &Path) -> Option<RawPom> {
@@ -521,7 +592,10 @@ impl Resolver {
        merge_by(&mut ctx.deps, &pom.deps, RawDep::key);
        merge_plugins(&mut ctx.plugins, &pom.plugins);
        merge_plugins(&mut ctx.managed_plugins, &pom.managed_plugins);
-        for p in pom.profiles.iter().filter(|p| p.active_by_default) {
+        if pom.compiler_release.is_some() {
+            ctx.compiler_release = pom.compiler_release.clone();
+        }
+        for p in self.active(&pom.profiles) {
            merge_by(&mut ctx.properties, &p.properties, |(k, _)| k.clone());
            merge_by(&mut ctx.deps, &p.deps, RawDep::key);
            merge_plugins(&mut ctx.plugins, &p.plugins);
@@ -637,7 +711,7 @@ pub(crate) fn launch_inputs(
        }
        Some(())
    }
-    let mut resolver = Resolver::new(local_repo.or_else(default_local_repo));
+    let mut resolver = Resolver::new(local_repo.or_else(default_local_repo), &[]);
    let mut out = Vec::new();
    for project in projects {
        let dir = root.join(&project.dir);
@@ -680,7 +754,76 @@ pub fn goal_prefix(artifact_id: &str) -> String {
    artifact_id.strip_suffix("-plugin").unwrap_or(artifact_id).to_owned()
 }

-/// Goals of well-known plugins (their plugin descriptors are not read).
+/// Goals of every plugin jar read so far, by the path of that jar.
+static DESCRIPTOR: OnceLock<Mutex<HashMap<String, Vec<String>>>> = OnceLock::new();
+
+/// `<goal>` names of the plugin descriptor inside its jar (`META-INF/maven/plugin.xml`),
+/// which is where Maven itself takes the list `plugin:help` prints. Empty when the jar
+/// is not in the local repository yet.
+fn descriptor_goals(repo: &Path, group_id: &str, artifact_id: &str, version: &str) -> Vec<String> {
+    // Keyed by the jar itself, not by its coordinates: a repository can be replaced
+    // between runs, and a test's empty repository must not answer for another's.
+    // One `push` per group segment: the layout is `<repo>/<group as directories>/…` on
+    // every platform, Windows' separator included.
+    let mut dir = repo.to_path_buf();
+    dir.extend(group_id.split('.'));
+    dir.push(artifact_id);
+    dir.push(version);
+    let Some(jar) = plugin_jar(&dir, artifact_id, version) else { return Vec::new() };
+    let key = jar.to_string_lossy().into_owned();
+    let cache = DESCRIPTOR.get_or_init(|| Mutex::new(HashMap::new()));
+    if let Some(cached) = cache.lock().unwrap_or_else(|e| e.into_inner()).get(&key) {
+        return cached.clone();
+    }
+    // A failed read is not remembered: the jar may be half written by Maven right now.
+    let Some(goals) = read_descriptor(&jar) else { return Vec::new() };
+    cache.lock().unwrap_or_else(|e| e.into_inner()).insert(key, goals.clone());
+    goals
+}
+
+/// The plugin's jar in its version directory: `<artifactId>-<version>.jar`, or — for a
+/// SNAPSHOT installed from a repository, whose file name carries a timestamp — the newest
+/// `<artifactId>-*.jar` that is neither sources nor javadoc.
+fn plugin_jar(dir: &Path, artifact_id: &str, version: &str) -> Option<PathBuf> {
+    let exact = dir.join(format!("{artifact_id}-{version}.jar"));
+    if exact.is_file() {
+        return Some(exact);
+    }
+    let prefix = format!("{artifact_id}-");
+    let mut best: Option<(std::time::SystemTime, PathBuf)> = None;
+    for entry in std::fs::read_dir(dir).ok()?.flatten() {
+        let path = entry.path();
+        let Some(name) = path.file_name().and_then(|n| n.to_str()) else { continue };
+        if !name.starts_with(&prefix) || !name.ends_with(".jar") || name.ends_with("-sources.jar") {
+            continue;
+        }
+        if name.ends_with("-javadoc.jar") {
+            continue;
+        }
+        let Ok(modified) = entry.metadata().and_then(|m| m.modified()) else { continue };
+        if best.as_ref().is_none_or(|(at, _)| modified > *at) {
+            best = Some((modified, path));
+        }
+    }
+    best.map(|(_, p)| p)
+}
+
+fn read_descriptor(jar: &Path) -> Option<Vec<String>> {
+    let file = std::fs::File::open(jar).ok()?;
+    let mut archive = zip::ZipArchive::new(file).ok()?;
+    let mut entry = archive.by_name("META-INF/maven/plugin.xml").ok()?;
+    let mut text = String::new();
+    entry.read_to_string(&mut text).ok()?;
+    let root = xml::parse(&text)?;
+    let mut goals: Vec<String> =
+        root.list("mojos", "mojo").iter().filter_map(|m| m.text_of("goal")).map(|g| g.trim().to_owned()).collect();
+    goals.retain(|g| !g.is_empty());
+    goals.sort();
+    goals.dedup();
+    Some(goals)
+}
+
+/// Goals of well-known plugins, for a jar that is not in the local repository yet.
 fn known_goals(artifact_id: &str) -> &'static [&'static str] {
    match artifact_id {
        "maven-clean-plugin" => &["clean", "help"],
@@ -832,9 +975,27 @@ fn lifecycle_plugins(packaging: &str) -> &'static [&'static str] {
    }
 }

-/// A plugin as shown in the tree: execution goals plus the plugin's known goals, sorted.
-pub(crate) fn plugin(group_id: &str, artifact_id: &str, version: Option<String>, goals: &[String]) -> MavenPlugin {
+/// A plugin as shown in the tree: the goals its jar declares, the ones known by name for
+/// the common plugins, and the ones the project binds in `<executions>`, sorted. IDEA lists
+/// a plugin's goals the same way, which is why a plugin outside the table (checkstyle, say)
+/// still shows every goal it offers instead of only the bound one.
+pub(crate) fn plugin(
+    group_id: &str,
+    artifact_id: &str,
+    version: Option<String>,
+    goals: &[String],
+    local_repo: Option<&Path>,
+) -> MavenPlugin {
    let mut all: Vec<String> = known_goals(artifact_id).iter().map(|g| (*g).to_owned()).collect();
+    let repo = local_repo.map(Path::to_path_buf).or_else(default_local_repo);
+    // An unresolved `${…}` version names no jar: the table and the bound goals stand in.
+    if let (Some(repo), Some(version)) = (repo.as_deref(), version.as_deref().filter(|v| !v.contains("${"))) {
+        for g in descriptor_goals(repo, group_id, artifact_id, version) {
+            if !all.contains(&g) {
+                all.push(g);
+            }
+        }
+    }
    for g in goals {
        if !all.contains(g) {
            all.push(g.clone());
@@ -862,13 +1023,19 @@ fn rel_path(root: &Path, p: &Path) -> String {
 }

 /// The POMs that are not modules of another one: the root `pom.xml`, else the
-/// shallowest `pom.xml` of each branch (a folder holding several builds).
+/// shallowest `pom.xml` of each branch (a folder holding several builds). An
+/// aggregate POM directly inside `src/` counts too (issue #1001: `src/pom.xml`
+/// with its modules beside it, `src/app/pom.xml` and so on).
 fn top_level_poms(root: &Path) -> Vec<PathBuf> {
    let top = root.join("pom.xml");
    if top.is_file() {
        return vec![top];
    }
    let mut out = Vec::new();
+    let src_pom = root.join("src").join("pom.xml");
+    if src_pom.is_file() {
+        out.push(src_pom);
+    }
    let mut queue: Vec<(PathBuf, usize)> = vec![(root.to_path_buf(), 0)];
    while let Some((dir, depth)) = queue.pop() {
        let Ok(entries) = std::fs::read_dir(&dir) else { continue };
@@ -882,9 +1049,16 @@ fn top_level_poms(root: &Path) -> Vec<PathBuf> {
        }
        dirs.sort();
        for d in dirs.into_iter().rev() {
-            if d.join("pom.xml").is_file() {
-                out.push(d.join("pom.xml"));
-            } else if depth + 1 < POM_SEARCH_DEPTH {
+            let pom = d.join("pom.xml");
+            if pom.is_file() {
+                out.push(pom);
+                continue;
+            }
+            let src_pom = d.join("src").join("pom.xml");
+            if src_pom.is_file() {
+                out.push(src_pom);
+            }
+            if depth + 1 < POM_SEARCH_DEPTH {
                queue.push((d, depth + 1));
            }
        }
@@ -926,12 +1100,77 @@ pub fn load(root: &Path) -> MavenModel {
    load_with_repo(root, default_local_repo())
 }

+/// [`load`] with the POMs `settings` link (Add Maven Projects).
+pub fn load_linked(root: &Path, settings: &ide_core::settings::MavenSettings) -> MavenModel {
+    load_with_linked(root, default_local_repo(), &[], &settings.linked_projects)
+}
+
 pub(crate) fn load_with_repo(root: &Path, local_repo: Option<PathBuf>) -> MavenModel {
-    let mut resolver = Resolver::new(local_repo);
+    load_with(root, local_repo, &[])
+}
+
+/// The `-P` entries' choice for profile `id`: on, off (`!id` / `-id`), or none (the last wins).
+fn profile_choice(chosen: &[String], id: &str) -> Option<bool> {
+    chosen.iter().rev().find_map(|c| {
+        let c = c.trim();
+        if c == id {
+            Some(true)
+        } else if c.strip_prefix('!').or_else(|| c.strip_prefix('-')) == Some(id) {
+            Some(false)
+        } else {
+            None
+        }
+    })
+}
+
+pub(crate) fn load_with(root: &Path, local_repo: Option<PathBuf>, profiles: &[String]) -> MavenModel {
+    load_with_linked(root, local_repo, profiles, &[])
+}
+
+/// The POMs of `linked` (project-relative, from Settings) that exist inside `root`.
+fn linked_poms(root: &Path, linked: &[String]) -> Vec<PathBuf> {
+    let base = dunce::canonicalize(root).unwrap_or_else(|_| root.to_path_buf());
+    let mut out: Vec<PathBuf> = Vec::new();
+    for pom in linked {
+        let pom = normalized_pom(pom);
+        if pom.is_empty() || pom.starts_with("../") || pom == ".." {
+            continue;
+        }
+        let path = root.join(&pom);
+        let inside = dunce::canonicalize(&path).is_ok_and(|p| p.starts_with(&base));
+        if path.is_file() && inside && !out.contains(&path) {
+            out.push(path);
+        }
+    }
+    out
+}
+
+/// Whether `root` holds a Maven build or the settings link one inside it.
+pub fn has_projects(root: &Path, settings: &ide_core::settings::MavenSettings) -> bool {
+    is_maven_project(root) || !linked_poms(root, &settings.linked_projects).is_empty()
+}
+
+/// The model with the chosen `profiles` (`-P` entries; `!id` deactivates: their modules,
+/// dependencies and properties are part of the model, those turned off are not) and the
+/// `linked` POMs (Add Maven Projects): builds that no reactor lists, shown as independent
+/// top-level projects. A linked POM that turns out to be a module of the root reactor stays that module.
+pub fn load_with_linked(
+    root: &Path,
+    local_repo: Option<PathBuf>,
+    profiles: &[String],
+    linked: &[String],
+) -> MavenModel {
+    let mut resolver = Resolver::new(local_repo, profiles);
    let mut model = MavenModel::default();
    let mut seen: HashSet<PathBuf> = HashSet::new();
-    // (pom, aggregated)
-    let mut stack: Vec<(PathBuf, bool)> = top_level_poms(root).into_iter().rev().map(|p| (p, false)).collect();
+    let mut tops = top_level_poms(root);
+    for pom in linked_poms(root, linked) {
+        if !tops.contains(&pom) {
+            tops.push(pom);
+        }
+    }
+    // (pom, aggregated); the root reactor and its modules come before linked POMs.
+    let mut stack: Vec<(PathBuf, bool)> = tops.into_iter().rev().map(|p| (p, false)).collect();
    while let Some((path, aggregated)) = stack.pop() {
        if model.projects.len() >= MAX_PROJECTS {
            break;
@@ -947,7 +1186,7 @@ pub(crate) fn load_with_repo(root: &Path, local_repo: Option<PathBuf>) -> MavenM
        let i = |s: &str| interpolate(s, &props);

        let mut module_names: Vec<String> = pom.modules.clone();
-        for p in pom.profiles.iter().filter(|p| p.active_by_default) {
+        for p in resolver.active(&pom.profiles) {
            module_names.extend(p.modules.iter().cloned());
        }
        let mut modules: Vec<PathBuf> = Vec::new();
@@ -999,14 +1238,14 @@ pub(crate) fn load_with_repo(root: &Path, local_repo: Option<PathBuf>) -> MavenM
                    .or_else(|| ctx.managed_plugins.iter().find(|m| m.key() == p.key()).and_then(|m| m.version.clone()))
                    .map(|v| i(&v))
                    .filter(|v| !v.contains("${"));
-                plugin(&i(&p.group_id), &i(&p.artifact_id), version, &p.goals)
+                plugin(&i(&p.group_id), &i(&p.artifact_id), version, &p.goals, resolver.local_repo.as_deref())
            })
            .collect();

        let jv = ["maven.compiler.release", "java.version", "maven.compiler.source", "maven.compiler.target"]
            .iter()
            .find_map(|k| props.get(*k).map(|v| i(v)))
-            .or_else(|| pom.compiler_release.as_deref().map(i))
+            .or_else(|| ctx.compiler_release.as_deref().map(i))
            .and_then(|v| java_version(&v));

        // The project can activate the profiles of its own POM and its ancestors'.
@@ -1053,7 +1292,7 @@ impl UnlinkedProjects {
        if settings.unlinked_projects.is_empty() {
            return Self::default();
        }
-        Self::from_model(&load(root), settings)
+        Self::from_model(&load_linked(root, settings), settings)
    }

    pub fn from_model(model: &MavenModel, settings: &ide_core::settings::MavenSettings) -> Self {
@@ -1079,6 +1318,40 @@ impl UnlinkedProjects {
        self.poms.iter().map(String::as_str)
    }

+    /// The POMs the Java language server should import when an unlinked POM is a module of a
+    /// linked reactor, else `None` (excluding the unlinked directories is enough then).
+    ///
+    /// jdtls imports an aggregator together with all of its modules, whatever its import
+    /// exclusions say, so a reactor keeping an unlinked module is left out; its other linked
+    /// modules are listed on their own. Such an aggregator (`pom` packaging) has no sources.
+    pub fn import_poms(&self, model: &MavenModel) -> Option<Vec<String>> {
+        let linked: Vec<&MavenProject> = model.projects.iter().filter(|p| !self.contains(&p.pom)).collect();
+        if !linked.iter().any(|p| p.modules.iter().any(|m| self.contains(m))) {
+            return None;
+        }
+        let by_pom: std::collections::HashMap<String, &MavenProject> =
+            model.projects.iter().map(|p| (normalized_pom(&p.pom), p)).collect();
+        // Whether `pom`'s module tree reaches an unlinked POM.
+        let reaches_unlinked = |pom: &str| {
+            let mut seen = std::collections::HashSet::new();
+            let mut pending = vec![normalized_pom(pom)];
+            while let Some(pom) = pending.pop() {
+                if !seen.insert(pom.clone()) {
+                    continue;
+                }
+                let Some(project) = by_pom.get(&pom) else { continue };
+                for module in &project.modules {
+                    if self.contains(module) {
+                        return true;
+                    }
+                    pending.push(normalized_pom(module));
+                }
+            }
+            false
+        };
+        Some(linked.into_iter().filter(|p| !reaches_unlinked(&p.pom)).map(|p| normalized_pom(&p.pom)).collect())
+    }
+
    pub fn filter(&self, model: &mut MavenModel) {
        model.projects.retain(|p| !self.contains(&p.pom));
        for project in &mut model.projects {
@@ -1111,6 +1384,16 @@ pub fn build_files(root: &Path, model: &MavenModel) -> Vec<PathBuf> {
 /// Projects and their plugins / dependencies from `mvn help:effective-pom` output
 /// (`<project>` or `<projects>`), keyed `groupId:artifactId`.
 pub fn parse_effective_pom(text: &str) -> Vec<(String, Vec<MavenPlugin>, Vec<MavenDependency>)> {
+    parse_effective_pom_in(text, None)
+}
+
+/// The same, with the local repository the project actually builds against (a
+/// `-Dmaven.repo.local` of the build, say): the plugin goals come from jars there,
+/// rather than from the user's default one.
+pub fn parse_effective_pom_in(
+    text: &str,
+    local_repo: Option<&Path>,
+) -> Vec<(String, Vec<MavenPlugin>, Vec<MavenDependency>)> {
    let Some(root) = xml::parse(text) else { return Vec::new() };
    let projects: Vec<&Element> =
        if root.name == "projects" { root.children_named("project").collect() } else { vec![&root] };
@@ -1122,7 +1405,7 @@ pub fn parse_effective_pom(text: &str) -> Vec<(String, Vec<MavenPlugin>, Vec<Mav
            let plugins = raw
                .plugins
                .iter()
-                .map(|pl| plugin(&pl.group_id, &pl.artifact_id, pl.version.clone(), &pl.goals))
+                .map(|pl| plugin(&pl.group_id, &pl.artifact_id, pl.version.clone(), &pl.goals, local_repo))
                .collect();
            let deps = raw
                .deps
@@ -1253,6 +1536,138 @@ pub fn parse_dependency_tree(output: &str) -> Vec<(String, Vec<MavenDependency>)
 mod tests {
    use super::*;

+    /// A plugin jar in `repo` whose descriptor declares `goals`.
+    fn write_plugin_jar(repo: &Path, group: &str, artifact: &str, version: &str, goals: &[&str]) {
+        let dir = repo.join(group.replace('.', "/")).join(artifact).join(version);
+        std::fs::create_dir_all(&dir).unwrap();
+        let mojos: String = goals.iter().map(|g| format!("<mojo><goal>{g}</goal></mojo>")).collect();
+        let descriptor = format!("<plugin><mojos>{mojos}</mojos></plugin>");
+        let file = std::fs::File::create(dir.join(format!("{artifact}-{version}.jar"))).unwrap();
+        let mut zip = zip::ZipWriter::new(file);
+        zip.start_file("META-INF/maven/plugin.xml", zip::write::SimpleFileOptions::default()).unwrap();
+        std::io::Write::write_all(&mut zip, descriptor.as_bytes()).unwrap();
+        zip.finish().unwrap();
+    }
+
+    #[test]
+    fn a_plugin_lists_the_goals_its_jar_declares() {
+        let tmp = tempfile::tempdir().unwrap();
+        let repo = tmp.path();
+        write_plugin_jar(
+            repo,
+            "org.apache.maven.plugins",
+            "maven-checkstyle-plugin",
+            "3.3.1",
+            &["checkstyle", "checkstyle-aggregate", "help", "check"],
+        );
+        let p = plugin(
+            "org.apache.maven.plugins",
+            "maven-checkstyle-plugin",
+            Some("3.3.1".into()),
+            &["check".to_owned()],
+            Some(repo),
+        );
+        assert_eq!(p.goals, ["check", "checkstyle", "checkstyle-aggregate", "help"], "every goal the plugin offers");
+        assert_eq!(p.prefix, "checkstyle");
+    }
+
+    #[test]
+    fn settings_profiles_are_listed_with_the_active_ones_checked() {
+        let tmp = tempfile::tempdir().unwrap();
+        let file = tmp.path().join("settings.xml");
+        std::fs::write(
+            &file,
+            r#"<settings>
+  <profiles>
+    <profile><id>nexus</id></profile>
+    <profile><id>jdk21</id><activation><activeByDefault>true</activeByDefault></activation></profile>
+    <profile><id>release</id></profile>
+    <profile><id>nexus</id></profile>
+    <profile><activation/></profile>
+  </profiles>
+  <activeProfiles><activeProfile>nexus</activeProfile></activeProfiles>
+</settings>"#,
+        )
+        .unwrap();
+        let p = |id: &str, active| MavenProfile { id: id.into(), active_by_default: active };
+        assert_eq!(settings_profiles(&file), [p("nexus", true), p("jdk21", true), p("release", false)]);
+        assert!(settings_profiles(&tmp.path().join("missing.xml")).is_empty());
+
+        let mut s = ide_core::settings::MavenSettings::default();
+        let home = dirs::home_dir().unwrap();
+        assert_eq!(user_settings_file(tmp.path(), &s), Some(home.join(".m2/settings.xml")));
+        s.user_settings = "conf/settings.xml".into();
+        assert_eq!(user_settings_file(tmp.path(), &s), Some(tmp.path().join("conf/settings.xml")));
+        s.user_settings = "~/work/settings.xml".into();
+        assert_eq!(user_settings_file(tmp.path(), &s), Some(home.join("work/settings.xml")));
+    }
+
+    #[test]
+    fn a_settings_file_names_the_repository_to_read_goals_from() {
+        let tmp = tempfile::tempdir().unwrap();
+        let settings = tmp.path().join("settings.xml");
+        std::fs::write(
+            &settings,
+            "<settings><localRepository>${user.home}/repo-from-settings</localRepository></settings>",
+        )
+        .unwrap();
+        let repo = local_repository_of(&settings).unwrap();
+        assert!(repo.ends_with("repo-from-settings"), "{}", repo.display());
+        assert!(!repo.to_string_lossy().contains("${user.home}"));
+        // A settings file that names none leaves Maven's default alone.
+        let plain = tmp.path().join("plain.xml");
+        std::fs::write(&plain, "<settings><offline>true</offline></settings>").unwrap();
+        assert!(local_repository_of(&plain).is_none());
+        assert!(local_repository_of(&tmp.path().join("missing.xml")).is_none());
+    }
+
+    #[test]
+    fn effective_pom_goals_come_from_the_local_repository_it_is_given() {
+        let tmp = tempfile::tempdir().unwrap();
+        write_plugin_jar(tmp.path(), "org.apache.maven.plugins", "maven-demo-plugin", "1.0", &["run", "help"]);
+        let text = "<project><groupId>g</groupId><artifactId>a</artifactId><build><plugins>\
+            <plugin><groupId>org.apache.maven.plugins</groupId><artifactId>maven-demo-plugin</artifactId>\
+            <version>1.0</version><executions><execution><goals><goal>run</goal></goals></execution></executions>\
+            </plugin></plugins></build></project>";
+        let with_repo = parse_effective_pom_in(text, Some(tmp.path()));
+        assert_eq!(with_repo[0].1[0].goals, ["help", "run"], "the jar's own goals come first");
+        // Without that repository the plugin is unknown: only what the project binds.
+        assert_eq!(parse_effective_pom(text)[0].1[0].goals, ["run"]);
+    }
+
+    #[test]
+    fn a_snapshot_plugin_is_found_by_its_timestamped_jar() {
+        let tmp = tempfile::tempdir().unwrap();
+        let dir = tmp.path().join("g/p/maven-demo-plugin/1.0-SNAPSHOT");
+        std::fs::create_dir_all(&dir).unwrap();
+        let descriptor = "<plugin><mojos><mojo><goal>run</goal></mojo></mojos></plugin>";
+        let file = std::fs::File::create(dir.join("maven-demo-plugin-1.0-20240101.120000-3.jar")).unwrap();
+        let mut zip = zip::ZipWriter::new(file);
+        zip.start_file("META-INF/maven/plugin.xml", zip::write::SimpleFileOptions::default()).unwrap();
+        std::io::Write::write_all(&mut zip, descriptor.as_bytes()).unwrap();
+        zip.finish().unwrap();
+        // A sibling sources jar must not win.
+        std::fs::File::create(dir.join("maven-demo-plugin-1.0-20240101.120000-3-sources.jar")).unwrap();
+        let p = plugin("g.p", "maven-demo-plugin", Some("1.0-SNAPSHOT".into()), &[], Some(tmp.path()));
+        assert_eq!(p.goals, ["run"]);
+    }
+
+    #[test]
+    fn a_plugin_without_its_jar_keeps_the_table_and_the_bound_goals() {
+        let tmp = tempfile::tempdir().unwrap();
+        let p = plugin(
+            "org.apache.maven.plugins",
+            "maven-checkstyle-plugin",
+            Some("3.3.1".into()),
+            &["check".to_owned()],
+            Some(tmp.path()),
+        );
+        assert_eq!(p.goals, ["check"], "nothing beyond what the project binds");
+        let known =
+            plugin("org.apache.maven.plugins", "maven-compiler-plugin", Some("3.13.0".into()), &[], Some(tmp.path()));
+        assert_eq!(known.goals, ["compile", "help", "testCompile"], "the common plugins keep their table");
+    }
+
    fn write(dir: &Path, rel: &str, text: &str) {
        let p = dir.join(rel);
        std::fs::create_dir_all(p.parent().unwrap()).unwrap();
@@ -1276,6 +1691,72 @@ mod tests {
      </profiles>
    </project>"#;

+    #[test]
+    fn maven_4_subprojects_are_modules() {
+        let tmp = tempfile::tempdir().unwrap();
+        let root = tmp.path();
+        write(
+            root,
+            "pom.xml",
+            r#"<project xmlns="http://maven.apache.org/POM/4.1.0"><modelVersion>4.1.0</modelVersion>
+              <groupId>demo</groupId><artifactId>parent</artifactId><version>1.0</version><packaging>pom</packaging>
+              <subprojects><subproject>core</subproject></subprojects>
+              <profiles><profile><id>extra</id><subprojects><subproject>extra</subproject></subprojects></profile></profiles>
+            </project>"#,
+        );
+        write(root, "core/pom.xml", "<project><artifactId>core</artifactId></project>");
+        write(root, "extra/pom.xml", "<project><artifactId>extra</artifactId></project>");
+        let model = load_with_repo(root, None);
+        assert_eq!(model.projects[0].modules, ["core/pom.xml"]);
+        assert!(model.projects.iter().any(|p| p.pom == "core/pom.xml" && p.aggregated));
+    }
+
+    #[test]
+    fn modules_inherit_the_compiler_level_of_the_parent_plugin_configuration() {
+        let tmp = tempfile::tempdir().unwrap();
+        let root = tmp.path();
+        let parent = |build: &str| {
+            format!(
+                r#"<project><groupId>demo</groupId><artifactId>parent</artifactId><version>1.0</version><packaging>pom</packaging>
+                  <modules><module>core</module><module>app</module></modules>
+                  <properties><jdk>17</jdk></properties>{build}</project>"#
+            )
+        };
+        let child = |name: &str, build: &str| {
+            format!(
+                r#"<project><parent><groupId>demo</groupId><artifactId>parent</artifactId><version>1.0</version></parent>
+                  <artifactId>{name}</artifactId>{build}</project>"#
+            )
+        };
+        let compiler = |level: &str| {
+            format!(
+                "<plugin><artifactId>maven-compiler-plugin</artifactId><configuration><source>{level}</source></configuration></plugin>"
+            )
+        };
+        let versions = |model: &MavenModel| -> Vec<(String, Option<u32>)> {
+            model.projects.iter().map(|p| (p.pom.clone(), p.java_version)).collect()
+        };
+        let app_build = format!("<build><plugins>{}</plugins></build>", compiler("21"));
+        write(root, "core/pom.xml", &child("core", ""));
+        write(root, "app/pom.xml", &child("app", &app_build));
+        for build in [
+            format!("<build><pluginManagement><plugins>{}</plugins></pluginManagement></build>", compiler("${jdk}")),
+            format!("<build><plugins>{}</plugins></build>", compiler("1.8")),
+        ] {
+            write(root, "pom.xml", &parent(&build));
+            let expected = if build.contains("1.8") { 8 } else { 17 };
+            assert_eq!(
+                versions(&load_with_repo(root, None)),
+                [
+                    ("pom.xml".to_owned(), Some(expected)),
+                    ("core/pom.xml".to_owned(), Some(expected)),
+                    ("app/pom.xml".to_owned(), Some(21)),
+                ],
+                "{build}"
+            );
+        }
+    }
+
    #[test]
    fn multi_module_parent_properties_and_managed_versions() {
        let tmp = tempfile::tempdir().unwrap();
@@ -1359,6 +1840,95 @@ mod tests {
        assert!(model.projects.iter().all(|p| p.command == if cfg!(windows) { "mvn.cmd" } else { "mvn" }));
    }

+    /// Add Maven Projects: a POM inside the project that no reactor lists becomes an
+    /// independent top-level project; one the root reactor lists stays its module.
+    #[test]
+    fn linked_poms_outside_the_reactor_are_top_level_projects() {
+        let tmp = tempfile::tempdir().unwrap();
+        let root = tmp.path();
+        write(
+            root,
+            "pom.xml",
+            "<project><groupId>demo</groupId><artifactId>main</artifactId><version>1.0</version><packaging>pom</packaging><modules><module>core</module></modules></project>",
+        );
+        write(
+            root,
+            "core/pom.xml",
+            "<project><groupId>demo</groupId><artifactId>core</artifactId><version>1.0</version></project>",
+        );
+        write(
+            root,
+            "stub/pom.xml",
+            "<project><groupId>demo</groupId><artifactId>stub</artifactId><version>1.0</version></project>",
+        );
+        let top = |m: &MavenModel| m.projects.iter().map(|p| (p.dir.clone(), p.aggregated)).collect::<Vec<_>>();
+
+        assert_eq!(top(&load_with_linked(root, None, &[], &[])), [("".into(), false), ("core".into(), true)]);
+        let linked: Vec<String> =
+            ["stub/pom.xml", "./core/pom.xml", "../outside/pom.xml", "missing/pom.xml"].map(String::from).into();
+        assert_eq!(
+            top(&load_with_linked(root, None, &[], &linked)),
+            [("".into(), false), ("core".into(), true), ("stub".into(), false)]
+        );
+
+        // Deeper than the folder search reaches: only the link makes it a Maven project.
+        let deep = tempfile::tempdir().unwrap();
+        write(deep.path(), "a/b/c/tool/pom.xml", "<project><artifactId>tool</artifactId></project>");
+        let settings = ide_core::settings::MavenSettings {
+            linked_projects: vec!["a/b/c/tool/pom.xml".into()],
+            ..Default::default()
+        };
+        assert!(!has_projects(deep.path(), &Default::default()));
+        assert!(has_projects(deep.path(), &settings));
+        assert_eq!(top(&load_linked(deep.path(), &settings)), [("a/b/c/tool".into(), false)]);
+    }
+
+    #[test]
+    fn chosen_profiles_bring_their_modules_and_dependencies() {
+        let tmp = tempfile::tempdir().unwrap();
+        let root = tmp.path();
+        write(
+            root,
+            "pom.xml",
+            r#"<project><groupId>demo</groupId><artifactId>parent</artifactId><version>1.0</version><packaging>pom</packaging>
+              <modules><module>core</module></modules>
+              <profiles>
+                <profile><id>flink-1.17</id><activation><activeByDefault>true</activeByDefault></activation>
+                  <modules><module>flink-1.17</module></modules></profile>
+                <profile><id>flink-1.20</id><modules><module>flink-1.20</module></modules>
+                  <dependencies><dependency><groupId>org.apache.flink</groupId><artifactId>flink-core</artifactId><version>1.20.0</version></dependency></dependencies>
+                </profile>
+              </profiles>
+            </project>"#,
+        );
+        for m in ["core", "flink-1.17", "flink-1.20"] {
+            write(
+                root,
+                &format!("{m}/pom.xml"),
+                &format!(
+                    "<project><parent><groupId>demo</groupId><artifactId>parent</artifactId><version>1.0</version></parent><artifactId>{m}</artifactId></project>"
+                ),
+            );
+        }
+        let dirs = |m: &MavenModel| m.projects.iter().map(|p| p.dir.clone()).collect::<Vec<_>>();
+        let flink = |m: &MavenModel, dir: &str| {
+            m.projects.iter().find(|p| p.dir == dir).unwrap().dependencies.iter().any(|d| d.artifact_id == "flink-core")
+        };
+
+        let default = load_with(root, None, &[]);
+        assert_eq!(dirs(&default), ["", "core", "flink-1.17"]);
+        assert!(!flink(&default, "core"));
+
+        // Choosing another profile of the POM turns its activeByDefault one off (as `-P` does).
+        let chosen = load_with(root, None, &["flink-1.20".into()]);
+        assert_eq!(dirs(&chosen), ["", "core", "flink-1.20"]);
+        assert!(flink(&chosen, "core"), "a module inherits the chosen profile's dependencies");
+
+        let both = load_with(root, None, &["flink-1.20".into(), "flink-1.17".into()]);
+        assert_eq!(dirs(&both), ["", "core", "flink-1.17", "flink-1.20"]);
+        assert_eq!(dirs(&load_with(root, None, &["!flink-1.17".into()])), ["", "core"]);
+    }
+
    #[test]
    fn profiles_of_a_parent_pom_are_inherited() {
        let tmp = tempfile::tempdir().unwrap();
@@ -1471,6 +2041,25 @@ mod tests {
        assert!(!is_maven_project(&root.join("c")));
    }

+    #[test]
+    fn aggregate_pom_in_src_is_a_build() {
+        // Issue #1001: `src/pom.xml` aggregating modules under `src/` is recognized,
+        // with its modules loaded — while `src` stays unsearched otherwise.
+        let tmp = tempfile::tempdir().unwrap();
+        let root = tmp.path();
+        write(
+            root,
+            "src/pom.xml",
+            "<project><groupId>g</groupId><artifactId>parent</artifactId><packaging>pom</packaging>\
+             <modules><module>app</module></modules></project>",
+        );
+        write(root, "src/app/pom.xml", "<project><groupId>g</groupId><artifactId>app</artifactId></project>");
+        let model = load_with_repo(root, None);
+        let names: Vec<&str> = model.projects.iter().map(|p| p.artifact_id.as_str()).collect();
+        assert_eq!(names, ["parent", "app"]);
+        assert!(is_maven_project(root));
+    }
+
    #[test]
    fn property_interpolation() {
        let props: HashMap<String, String> =
@@ -1668,4 +2257,51 @@ mod linkage_tests {
        UnlinkedProjects::from_model(&original, &MavenSettings::default()).filter(&mut restored);
        assert_eq!(restored, original);
    }
+
+    #[test]
+    fn language_server_imports_reactor_modules_individually_once_one_is_unlinked() {
+        let tmp = tempfile::tempdir().unwrap();
+        let root = tmp.path();
+        // r ─┬─ x
+        //    ├─ y ─┬─ y/y1
+        //    │     └─ y/y2
+        //    └─ z          other/ is a separate root.
+        for (dir, modules) in [
+            ("r", "<modules><module>x</module><module>y</module><module>z</module></modules>"),
+            ("r/x", ""),
+            ("r/y", "<modules><module>y1</module><module>y2</module></modules>"),
+            ("r/y/y1", ""),
+            ("r/y/y2", ""),
+            ("r/z", ""),
+            ("other", ""),
+        ] {
+            std::fs::create_dir_all(root.join(dir)).unwrap();
+            std::fs::write(
+                root.join(dir).join("pom.xml"),
+                format!("<project><artifactId>{dir}</artifactId>{modules}</project>"),
+            )
+            .unwrap();
+        }
+        let model = load_with_repo(root, None);
+        let cases: [(&[&str], Option<&[&str]>); 5] = [
+            // Nothing unlinked, or whole roots: the import exclusions do it.
+            (&[], None),
+            (&["other/pom.xml"], None),
+            (&["r/pom.xml"], None),
+            // A module of a linked reactor: every other linked POM, minus the aggregators above it.
+            (&["r/y/y1/pom.xml"], Some(&["other/pom.xml", "r/x/pom.xml", "r/y/y2/pom.xml", "r/z/pom.xml"])),
+            (&["./r/y/pom.xml"], Some(&["other/pom.xml", "r/x/pom.xml", "r/z/pom.xml"])),
+        ];
+        for (unlinked, expected) in cases {
+            let settings = MavenSettings {
+                unlinked_projects: unlinked.iter().map(|s| s.to_string()).collect(),
+                ..Default::default()
+            };
+            let mut poms = UnlinkedProjects::from_model(&model, &settings).import_poms(&model);
+            if let Some(poms) = &mut poms {
+                poms.sort();
+            }
+            assert_eq!(poms, expected.map(|e| e.iter().map(|s| s.to_string()).collect::<Vec<_>>()), "{unlinked:?}");
+        }
+    }
 }
@@ -2,11 +2,12 @@
 //! line to a callback, and cancellation kills the whole process group (the
 //! `mvnw` / `gradlew` wrapper scripts start the JVM as a child).

+use ide_core::process::kill_tree;
 use ide_core::{CancellationToken, IdeError, IdeResult};
 use std::collections::BTreeMap;
 use std::io::{BufRead, BufReader, Read};
 use std::path::Path;
-use std::process::{Child, Command, Stdio};
+use std::process::{Command, Stdio};
 use std::sync::mpsc;
 use std::time::Duration;

@@ -22,18 +23,6 @@ pub(crate) struct Output {
    pub text: String,
 }

-fn kill_tree(child: &mut Child) {
-    #[cfg(unix)]
-    if let Ok(pid) = i32::try_from(child.id()) {
-        // SAFETY: plain syscall; the group was created by `process_group(0)` at spawn.
-        unsafe {
-            libc::kill(-pid, libc::SIGKILL);
-        }
-    }
-    let _ = child.kill();
-    let _ = child.wait();
-}
-
 /// `program` as spawnable: a bare name (`mvn`, `mvn.cmd`) resolves on the IDE's
 /// search path — the login shell's `PATH` plus version-manager shims — since the
 /// app's own `PATH` can be minimal and `Command` would not see `mvn` there.
@@ -80,12 +69,8 @@ pub(crate) fn run_with_env(
    let mut command = Command::new(&program);
    command.args(args).current_dir(cwd).envs(env).envs(encoding.env.iter().map(|(k, v)| (k, v))).stdin(Stdio::null());
    command.stdout(Stdio::piped()).stderr(Stdio::piped());
-    #[cfg(unix)]
-    {
-        use std::os::unix::process::CommandExt;
-        command.process_group(0);
-    }
-    ide_core::process::prepare(&mut command);
+    // Its own group: `mvnw` / `gradlew` start the JVM as a child, and cancelling kills both.
+    ide_core::process::prepare(ide_core::process::own_group(&mut command));
    if clear_env {
        command.env_clear().envs(env).envs(encoding.env);
    }
@@ -4,14 +4,16 @@
 //! per project (`maven.json`, `gradle.json` in the cache directory) and merged
 //! into the static model by [`crate::load`]; a changed build file marks them stale.

-use crate::gradle::{self, GradleModel, GradleTask};
+use crate::gradle::{self, GradleModel, GradleTask, ReportedProject, parse_reported_projects};
 use crate::maven::{self, MavenDependency, MavenModel, MavenPlugin};
 use crate::process::{self, Output};
 use ide_core::{CancellationToken, IdeError, IdeResult};
 use serde::{Deserialize, Serialize, de::DeserializeOwned};
 use specta::Type;
-use std::collections::BTreeMap;
+use std::collections::{BTreeMap, HashMap};
 use std::path::{Path, PathBuf};
+use std::sync::{Arc, LazyLock, Mutex};
+use std::time::SystemTime;

 #[derive(Clone, Debug, Serialize, Deserialize, Type)]
 #[serde(rename_all = "camelCase")]
@@ -48,6 +50,11 @@ struct CachedMavenProject {

 #[derive(Clone, Debug, Default, Serialize, Deserialize)]
 struct MavenCache {
+    /// Bumped whenever what the cache holds stops matching what the model would be
+    /// built as now (plugin goals read from a descriptor, say): an older cache is
+    /// dropped instead of shadowing the model.
+    #[serde(default)]
+    version: u32,
    hash: String,
    at_ms: f64,
    error: Option<String>,
@@ -63,9 +70,16 @@ struct GradleCache {
    at_ms: f64,
    error: Option<String>,
    tasks: Vec<(String, GradleTask)>,
+    /// The projects as Gradle evaluated them; empty in caches from before they were read.
+    #[serde(default)]
+    projects: Vec<ReportedProject>,
 }

+/// Init script printing every project, its source sets and Java version once configured.
+const MODEL_INIT_SCRIPT: &str = include_str!("gradle-model.gradle");
+
 const MAVEN_CACHE: &str = "maven.json";
+const MAVEN_CACHE_VERSION: u32 = 1;

 /// `dependency:tree` of a plugin version whose `-Dverbose` lists the occurrences Maven
 /// omitted (conflicts, duplicates): verbose output was dropped in 3.0 and is back since 3.2.
@@ -82,6 +96,24 @@ fn maven_sync_goals(effective: &Path, offline: bool) -> Vec<String> {
    ]
 }
 const GRADLE_CACHE: &str = "gradle.json";
+const MAVEN_PROFILES: &str = "maven-profiles.json";
+
+/// The Maven profiles (`-P` entries, `!id` deactivates) the project was last synced
+/// with: what the IDE resolves it with besides `mvn` (the Java language server, Build Project).
+pub fn maven_profiles(cache_dir: &Path) -> Vec<String> {
+    read_cache(cache_dir, MAVEN_PROFILES).unwrap_or_default()
+}
+
+/// Records the profiles of a sync for [`maven_profiles`]; `true` when they changed.
+pub fn save_maven_profiles(cache_dir: &Path, profiles: &[String]) -> IdeResult<bool> {
+    if maven_profiles(cache_dir) == profiles {
+        return Ok(false);
+    }
+    std::fs::create_dir_all(cache_dir)?;
+    let json = serde_json::to_vec(profiles).map_err(|e| IdeError::internal(e.to_string()))?;
+    std::fs::write(cache_dir.join(MAVEN_PROFILES), json)?;
+    Ok(true)
+}

 fn read_cache<T: DeserializeOwned>(dir: &Path, name: &str) -> Option<T> {
    serde_json::from_slice(&std::fs::read(dir.join(name)).ok()?).ok()
@@ -98,6 +130,20 @@ fn write_cache<T: Serialize>(dir: &Path, name: &str, value: &T) -> IdeResult<()>

 /// FNV-1a over the paths and contents of `files` (missing files count as empty).
 fn hash_files(files: &[PathBuf]) -> String {
+    hash_contents(files, |f| std::fs::read(f).unwrap_or_default())
+}
+
+/// Like IDEA's auto-import CRC: editing a comment or reformatting a build script
+/// does not make the last sync stale.
+fn hash_gradle_files(files: &[PathBuf]) -> String {
+    hash_contents(files, |f| {
+        let text = std::fs::read_to_string(f).unwrap_or_default();
+        let script = f.extension().is_some_and(|e| e == "gradle" || e == "kts");
+        if script { gradle::script_fingerprint(&text) } else { text }.into_bytes()
+    })
+}
+
+fn hash_contents(files: &[PathBuf], read: impl Fn(&Path) -> Vec<u8>) -> String {
    let mut h: u64 = 0xcbf29ce484222325;
    let mut feed = |bytes: &[u8]| {
        for b in bytes {
@@ -108,7 +154,7 @@ fn hash_files(files: &[PathBuf]) -> String {
    for f in files {
        feed(f.to_string_lossy().as_bytes());
        feed(&[0]);
-        feed(&std::fs::read(f).unwrap_or_default());
+        feed(&read(f));
        feed(&[0]);
    }
    format!("{h:016x}")
@@ -121,6 +167,9 @@ fn now_ms() -> f64 {
 /// Merges the cached effective build into `model`.
 pub fn apply_maven_cache(root: &Path, cache_dir: &Path, model: &mut MavenModel) {
    let Some(cache) = read_cache::<MavenCache>(cache_dir, MAVEN_CACHE) else { return };
+    if cache.version != MAVEN_CACHE_VERSION {
+        return; // built by an older IDE: what it holds no longer matches the model
+    }
    model.synced_at = Some(cache.at_ms);
    model.sync_error = cache.error;
    let changed = cache.hash != hash_files(&maven::build_files(root, model));
@@ -141,9 +190,33 @@ pub fn apply_maven_cache(root: &Path, cache_dir: &Path, model: &mut MavenModel)
    }
 }

+/// The projects of the last successful Gradle sync.
+/// Parsed once per change of the cache file (modification time and size): content and source
+/// roots are read on hot paths (every references search, Find in Files, repository scans).
+pub fn reported_gradle_projects(cache_dir: &Path) -> Arc<Vec<ReportedProject>> {
+    type Memo = HashMap<PathBuf, (Option<SystemTime>, u64, Arc<Vec<ReportedProject>>)>;
+    static MEMO: LazyLock<Mutex<Memo>> = LazyLock::new(Default::default);
+    let path = cache_dir.join(GRADLE_CACHE);
+    let Ok(meta) = std::fs::metadata(&path) else {
+        MEMO.lock().unwrap_or_else(|e| e.into_inner()).remove(&path);
+        return Arc::default();
+    };
+    let stamp = (meta.modified().ok(), meta.len());
+    let mut memo = MEMO.lock().unwrap_or_else(|e| e.into_inner());
+    if let Some((modified, len, projects)) = memo.get(&path)
+        && (*modified, *len) == stamp
+    {
+        return projects.clone();
+    }
+    let projects = Arc::new(read_cache::<GradleCache>(cache_dir, GRADLE_CACHE).map(|c| c.projects).unwrap_or_default());
+    memo.insert(path, (stamp.0, stamp.1, projects.clone()));
+    projects
+}
+
 /// Merges the cached task list into `model`.
 pub fn apply_gradle_cache(root: &Path, cache_dir: &Path, model: &mut GradleModel) {
    let Some(cache) = read_cache::<GradleCache>(cache_dir, GRADLE_CACHE) else { return };
+    gradle::merge_reported_projects(root, model, &cache.projects);
    if !cache.tasks.is_empty() {
        for p in &mut model.projects {
            let tasks: Vec<GradleTask> =
@@ -153,9 +226,11 @@ pub fn apply_gradle_cache(root: &Path, cache_dir: &Path, model: &mut GradleModel
            }
        }
    }
+    // A successful sync from before projects were cached has not seen computed includes.
+    let without_projects = cache.error.is_none() && cache.projects.is_empty();
    model.synced_at = Some(cache.at_ms);
    model.sync_error = cache.error;
-    model.stale = cache.hash != hash_files(&gradle::build_files(root, model));
+    model.stale = without_projects || cache.hash != hash_gradle_files(&gradle::build_files(root, model));
 }

 // ---------------------------------------------------------------- processes
@@ -208,16 +283,47 @@ pub fn sync_maven(
    cancel: &CancellationToken,
    progress: &dyn Fn(SyncProgress),
 ) -> IdeResult<()> {
-    let mut model = maven::load(root);
+    let mut model = maven::load_with_linked(
+        root,
+        maven::default_local_repo(),
+        &options.profiles,
+        &options.maven_settings.linked_projects,
+    );
    maven::UnlinkedProjects::from_model(&model, &options.maven_settings).filter(&mut model);
    std::fs::create_dir_all(cache_dir)?;
-    let mut cache =
-        MavenCache { hash: hash_files(&maven::build_files(root, &model)), verbose: true, ..MavenCache::default() };
+    let mut cache = MavenCache {
+        version: MAVEN_CACHE_VERSION,
+        hash: hash_files(&maven::build_files(root, &model)),
+        verbose: true,
+        ..MavenCache::default()
+    };
+    // Where the build resolves its jars, and therefore where the plugin goals are read
+    // from: `-Dmaven.repo.local=` first, then `<localRepository>` of the `-s` settings,
+    // then the user's default repository (which `plugin()` resolves itself).
+    let local_repo: Option<PathBuf> =
+        options.maven_options.iter().find_map(|a| a.strip_prefix("-Dmaven.repo.local=")).map(PathBuf::from).or_else(
+            || {
+                let mut args = options.maven_options.iter();
+                while let Some(arg) = args.next() {
+                    let path = match arg.as_str() {
+                        "-s" | "--settings" => args.next().map(String::as_str),
+                        _ => arg.strip_prefix("-s=").or_else(|| arg.strip_prefix("--settings=")),
+                    };
+                    if let Some(path) = path {
+                        return maven::local_repository_of(Path::new(path));
+                    }
+                }
+                None
+            },
+        );
    let mut errors: Vec<String> = Vec::new();
    for (n, top) in model.projects.iter().filter(|p| !p.aggregated).enumerate() {
        let effective = cache_dir.join(format!("effective-pom-{n}.xml"));
        let _ = std::fs::remove_file(&effective);
-        let mut args: Vec<String> = vec!["-B".into(), "-fae".into(), "-Dstyle.color=never".into()];
+        // `-T1` keeps mvnd serial: its default parallel build interleaves the
+        // `dependency:tree` output of concurrent modules, which the sync parses
+        // as one stream. mvn is serial anyway, so this only pins the daemon.
+        let mut args: Vec<String> = vec!["-B".into(), "-fae".into(), "-Dstyle.color=never".into(), "-T1".into()];
        args.extend(options.maven_options.iter().cloned());
        if options.offline {
            args.push("-o".into());
@@ -241,8 +347,9 @@ pub fn sync_maven(
                });
            }
        })?;
-        let effective_projects =
-            std::fs::read_to_string(&effective).map(|t| maven::parse_effective_pom(&t)).unwrap_or_default();
+        let effective_projects = std::fs::read_to_string(&effective)
+            .map(|t| maven::parse_effective_pom_in(&t, local_repo.as_deref()))
+            .unwrap_or_default();
        let trees = maven::parse_dependency_tree(&out.text);
        for (key, plugins, deps) in effective_projects {
            let dependencies = trees.iter().find(|(k, _)| *k == key).map(|(_, t)| t.clone()).unwrap_or(deps);
@@ -272,32 +379,188 @@ pub fn sync_gradle(
    progress: &dyn Fn(SyncProgress),
 ) -> IdeResult<()> {
    let model = gradle::load(root).ok_or_else(|| IdeError::not_found("no Gradle build in this project"))?;
-    let mut args: Vec<String> = vec!["--console=plain".into(), "-q".into(), "tasks".into(), "--all".into()];
+    sync_gradle_model(root, cache_dir, &model, options, cancel, progress)
+}
+
+/// Syncs this exact linked build; another build's task paths and cache cannot interfere.
+pub fn sync_gradle_model(
+    root: &Path,
+    cache_dir: &Path,
+    model: &GradleModel,
+    options: &SyncOptions,
+    cancel: &CancellationToken,
+    progress: &dyn Fn(SyncProgress),
+) -> IdeResult<()> {
+    if cancel.is_cancelled() {
+        return Err(IdeError::cancelled());
+    }
+    let mut model = model.clone();
+    let cache_dir = gradle::cache_dir(cache_dir, &model.dir);
+    std::fs::create_dir_all(&cache_dir)?;
+    let init_script = cache_dir.join("openidea-model.gradle");
+    std::fs::write(&init_script, MODEL_INIT_SCRIPT)?;
+    let mut args: Vec<String> = vec![
+        "--console=plain".into(),
+        "-q".into(),
+        "--init-script".into(),
+        init_script.to_string_lossy().into_owned(),
+        "tasks".into(),
+        "--all".into(),
+    ];
    if options.offline {
        args.push("--offline".into());
    }
    progress(SyncProgress { message: "Loading Gradle tasks".into(), fraction: None });
-    let out = run(
+    let out = match run(
        options.gradle_command.as_deref().unwrap_or(&model.command),
        &args,
        &root.join(&model.dir),
        &options.env,
        cancel,
        |_| {},
-    )?;
+    ) {
+        Ok(out) => out,
+        Err(_) if cancel.is_cancelled() => return Err(IdeError::cancelled()),
+        Err(error) if error.kind == ide_core::error::ErrorKind::Unavailable => {
+            Output { success: false, text: error.message }
+        }
+        Err(error) => return Err(error),
+    };
+    if cancel.is_cancelled() {
+        return Err(IdeError::cancelled());
+    }
+    let projects = if out.success { parse_reported_projects(&out.text) } else { Vec::new() };
+    // Hash the build files of the reported projects, or the model is stale right after the sync.
+    gradle::merge_reported_projects(root, &mut model, &projects);
    let cache = GradleCache {
-        hash: hash_files(&gradle::build_files(root, &model)),
+        hash: hash_gradle_files(&gradle::build_files(root, &model)),
        at_ms: now_ms(),
        error: (!out.success).then(|| error_summary(&out.text)),
        tasks: if out.success { gradle::parse_tasks(&out.text) } else { Vec::new() },
+        projects,
    };
-    write_cache(cache_dir, GRADLE_CACHE, &cache)
+    write_cache(&cache_dir, GRADLE_CACHE, &cache)
 }

 #[cfg(test)]
 mod tests {
    use super::*;

+    #[cfg(unix)]
+    #[test]
+    fn unavailable_gradle_launchers_are_cached_without_stopping_other_builds() {
+        use std::os::unix::fs::PermissionsExt;
+        let temp = tempfile::tempdir().unwrap();
+        let root = temp.path();
+        for dir in ["a", "b"] {
+            std::fs::create_dir(root.join(dir)).unwrap();
+            std::fs::write(root.join(dir).join("build.gradle"), "").unwrap();
+        }
+        let wrapper = root.join("b/gradlew");
+        std::fs::write(&wrapper, "#!/bin/sh\nprintf '%s\\n' 'Build tasks' '-----------' 'healthy - ok'\n").unwrap();
+        std::fs::set_permissions(&wrapper, std::fs::Permissions::from_mode(0o755)).unwrap();
+        let settings = ide_core::settings::GradleSettings {
+            linked_projects: Some(vec!["a".into(), "b".into()]),
+            ..Default::default()
+        };
+        let mut models = gradle::load_linked(root, &settings);
+        models[0].command = root.join("a/missing-gradlew").to_string_lossy().into_owned();
+        let cache = root.join("cache");
+        let run = |model: &GradleModel| {
+            sync_gradle_model(root, &cache, model, &SyncOptions::default(), &CancellationToken::new(), &|_| {})
+        };
+        for model in &models {
+            run(model).unwrap();
+        }
+        let loaded = crate::load_linked(root, &cache, None, &Default::default(), &settings);
+        assert!(loaded.gradle[0].sync_error.as_deref().unwrap().contains("cannot start"));
+        assert!(loaded.gradle[1].sync_error.is_none());
+        assert_eq!(loaded.gradle[1].projects[0].tasks[0].name, "healthy");
+        let bad_wrapper = root.join("a/gradlew");
+        std::fs::write(&bad_wrapper, "#!/bin/sh\nexit 0\n").unwrap();
+        std::fs::set_permissions(&bad_wrapper, std::fs::Permissions::from_mode(0o644)).unwrap();
+        models[0].command = bad_wrapper.to_string_lossy().into_owned();
+        run(&models[0]).unwrap();
+        let loaded = crate::load_linked(root, &cache, None, &Default::default(), &settings);
+        assert!(loaded.gradle[0].sync_error.as_deref().unwrap().contains("cannot start"));
+        assert!(loaded.gradle[1].sync_error.is_none());
+        let blocked_cache = root.join("blocked-cache");
+        std::fs::write(&blocked_cache, "a file cannot contain sync caches").unwrap();
+        assert!(
+            sync_gradle_model(
+                root,
+                &blocked_cache,
+                &models[0],
+                &SyncOptions::default(),
+                &CancellationToken::new(),
+                &|_| {}
+            )
+            .is_err()
+        );
+    }
+
+    #[cfg(unix)]
+    #[test]
+    fn independent_syncs_do_not_share_tasks_launchers_environments_or_failures() {
+        use std::os::unix::fs::PermissionsExt;
+        let temp = tempfile::tempdir().unwrap();
+        let root = temp.path();
+        for dir in ["a", "b"] {
+            let build = root.join(dir);
+            std::fs::create_dir_all(build.join("app")).unwrap();
+            std::fs::write(build.join("settings.gradle"), "include 'app'").unwrap();
+            std::fs::write(build.join("app/build.gradle"), "").unwrap();
+            let report = serde_json::json!({"path": ":app", "dir": build.join("app")});
+            let launcher = build.join("gradlew");
+            std::fs::write(
+                &launcher,
+                format!("#!/bin/sh\npwd > actual-cwd\nprintf '%s' \"$JAVA_HOME\" > actual-env\nprintf '%s\\n' '@openidea-model\t{report}' 'Build tasks' '-----------' 'app:custom{dir} - custom task'\n"),
+            ).unwrap();
+            std::fs::set_permissions(launcher, std::fs::Permissions::from_mode(0o755)).unwrap();
+        }
+        let settings = ide_core::settings::GradleSettings {
+            linked_projects: Some(vec!["a".into(), "b".into()]),
+            ..Default::default()
+        };
+        let cache = root.join("cache");
+        let models = gradle::load_linked(root, &settings);
+        for model in &models {
+            let options = SyncOptions {
+                env: BTreeMap::from([("JAVA_HOME".into(), format!("/jdk-{}", model.dir))]),
+                ..Default::default()
+            };
+            sync_gradle_model(root, &cache, model, &options, &CancellationToken::new(), &|_| {}).unwrap();
+            assert_eq!(
+                std::fs::read_to_string(root.join(&model.dir).join("actual-env")).unwrap(),
+                format!("/jdk-{}", model.dir)
+            );
+            assert_eq!(
+                std::fs::read_to_string(root.join(&model.dir).join("actual-cwd")).unwrap().trim(),
+                root.join(&model.dir).canonicalize().unwrap().to_string_lossy()
+            );
+        }
+        let load = || crate::load_linked(root, &cache, None, &Default::default(), &settings);
+        let model = load();
+        assert_eq!(model.gradle[0].projects[0].tasks[0].name, "customa");
+        assert_eq!(model.gradle[1].projects[0].tasks[0].name, "customb");
+        assert_ne!(gradle::cache_dir(&cache, "a"), gradle::cache_dir(&cache, "b"));
+        let before = std::fs::read(gradle::cache_dir(&cache, "a").join(GRADLE_CACHE)).unwrap();
+        std::fs::write(root.join("b/gradlew"), "#!/bin/sh\nprintf 'FAILURE: broken b\\n'\nexit 1\n").unwrap();
+        sync_gradle_model(root, &cache, &models[1], &SyncOptions::default(), &CancellationToken::new(), &|_| {})
+            .unwrap();
+        let model = load();
+        assert!(model.gradle[0].sync_error.is_none());
+        assert!(model.gradle[1].sync_error.is_some());
+        assert_eq!(std::fs::read(gradle::cache_dir(&cache, "a").join(GRADLE_CACHE)).unwrap(), before);
+        let cancel = CancellationToken::new();
+        cancel.cancel();
+        assert!(sync_gradle_model(root, &cache, &models[0], &SyncOptions::default(), &cancel, &|_| {}).is_err());
+        assert_eq!(std::fs::read(gradle::cache_dir(&cache, "a").join(GRADLE_CACHE)).unwrap(), before);
+        let unlinked = ide_core::settings::GradleSettings { linked_projects: Some(vec![]), ..Default::default() };
+        assert!(crate::load_linked(root, &cache, None, &Default::default(), &unlinked).gradle.is_empty());
+        assert!(crate::gradle_source_roots(root, &cache, &unlinked).is_empty());
+    }
+
    #[cfg(unix)]
    #[test]
    fn gradle_sync_uses_resolved_command_and_environment() {
@@ -332,6 +595,7 @@ mod tests {
        let mut model = maven::load_with_repo(&root, None);
        assert!(model.synced_at.is_none());
        let cache = MavenCache {
+            version: MAVEN_CACHE_VERSION,
            hash: hash_files(&maven::build_files(&root, &model)),
            at_ms: 5.0,
            error: None,
@@ -343,6 +607,7 @@ mod tests {
                    "maven-clean-plugin",
                    Some("3.2.0".into()),
                    &[],
+                    None,
                )],
                dependencies: vec![MavenDependency { artifact_id: "dep".into(), ..MavenDependency::default() }],
            }],
@@ -368,6 +633,128 @@ mod tests {
        assert_eq!(model.projects[0].dependencies[0].artifact_id, "fresh");
    }

+    #[test]
+    fn a_cache_from_an_older_ide_is_ignored() {
+        let tmp = tempfile::tempdir().unwrap();
+        let root = tmp.path().join("p");
+        let cache_dir = tmp.path().join("cache");
+        std::fs::create_dir_all(&root).unwrap();
+        std::fs::write(root.join("pom.xml"), "<project><groupId>g</groupId><artifactId>a</artifactId></project>")
+            .unwrap();
+        let mut model = maven::load_with_repo(&root, None);
+        let cache = MavenCache {
+            // What an older build wrote: no plugin descriptors were read back then, so
+            // its goal lists would shadow the ones the model now knows.
+            version: 0,
+            hash: hash_files(&maven::build_files(&root, &model)),
+            at_ms: 5.0,
+            error: None,
+            verbose: true,
+            projects: vec![CachedMavenProject {
+                key: "g:a".into(),
+                plugins: vec![maven::plugin(
+                    "org.apache.maven.plugins",
+                    "maven-clean-plugin",
+                    Some("3.2.0".into()),
+                    &[],
+                    None,
+                )],
+                dependencies: vec![MavenDependency { artifact_id: "cached".into(), ..MavenDependency::default() }],
+            }],
+        };
+        write_cache(&cache_dir, MAVEN_CACHE, &cache).unwrap();
+        apply_maven_cache(&root, &cache_dir, &mut model);
+        assert!(model.synced_at.is_none(), "the cache is dropped, the model stays unsynced");
+        assert!(model.projects[0].dependencies.iter().all(|d| d.artifact_id != "cached"));
+    }
+
+    #[test]
+    fn gradle_reported_projects_replace_static_ones() {
+        let tmp = tempfile::tempdir().unwrap();
+        let ws = dunce::canonicalize(tmp.path()).unwrap();
+        let root = ws.join("app");
+        let billing = ws.join("billing");
+        std::fs::create_dir_all(root.join("shared")).unwrap();
+        std::fs::create_dir_all(billing.join("modules/core")).unwrap();
+        // Computed includes: nothing a static reading can see.
+        std::fs::write(root.join("settings.gradle"), "rootProject.name = 'Shop'\n['billing'].each { includeFlat it }")
+            .unwrap();
+        std::fs::write(billing.join("modules/core/build.gradle"), "apply plugin: 'java'").unwrap();
+        // Built with serde: a Windows path holds backslashes, which raw JSON text would leave unescaped.
+        let line = |p: ReportedProject| format!("@openidea-model\t{}\n", serde_json::to_string(&p).unwrap());
+        let (r, b) = (root.display().to_string(), billing.display().to_string());
+        let core_src = |p: &str| format!("{b}/modules/core/src/{p}");
+        let set = |name: &str, test: bool, src: &[&str], res: &[&str]| gradle::ReportedSourceSet {
+            name: name.into(),
+            test,
+            src: src.iter().map(|p| core_src(p)).collect(),
+            res: res.iter().map(|p| core_src(p)).collect(),
+        };
+        // A settings script's own println comes first; task listing lines follow.
+        let out = format!(
+            "configuring billing\n{}{}{}@openidea-model\t{{broken\n\nOther tasks\n-----------\nbilling:core:jar\n",
+            line(ReportedProject { path: ":".into(), dir: r.clone(), ..ReportedProject::default() }),
+            line(ReportedProject {
+                path: ":billing".into(),
+                dir: b.clone(),
+                java: Some(17),
+                ..ReportedProject::default()
+            }),
+            line(ReportedProject {
+                path: ":billing:core".into(),
+                dir: format!("{b}/modules/core"),
+                java: Some(21),
+                source_sets: vec![
+                    set("main", false, &["main/java"], &["main/resources"]),
+                    set("test", true, &["main/java", "test/java"], &[]),
+                ],
+                ..ReportedProject::default()
+            }),
+        );
+        let projects = parse_reported_projects(&out);
+        assert_eq!(projects.len(), 3, "the malformed line is skipped");
+        let src = |p: &str| PathBuf::from(core_src(p));
+        assert_eq!(
+            gradle::reported_source_roots(&projects),
+            [
+                (src("main/java"), gradle::ReportedRoot::Source),
+                (src("main/resources"), gradle::ReportedRoot::Resources),
+                (src("test/java"), gradle::ReportedRoot::Test),
+            ]
+        );
+        let mut model = gradle::load(&root).unwrap();
+        assert_eq!(model.projects.len(), 1);
+        gradle::merge_reported_projects(&root, &mut model, &projects);
+        let paths: Vec<_> = model.projects.iter().map(|p| (p.path.as_str(), p.name.as_str())).collect();
+        assert_eq!(paths, [(":", "Shop"), (":billing", "billing"), (":billing:core", "core")]);
+        assert_eq!(model.projects[0].dir, "");
+        assert!(root.join(model.projects[2].build_file.as_ref().unwrap()).is_file());
+        assert_eq!(
+            gradle::external_roots(&root, model.projects.iter().map(|p| p.dir.as_str())),
+            std::slice::from_ref(&billing)
+        );
+        assert_eq!(model.java_version, Some(21), "the newest version any module needs");
+        assert_eq!(
+            gradle::parse_tasks(&out),
+            [(":billing:core".into(), GradleTask { name: "jar".into(), group: "other".into(), description: None })]
+        );
+
+        // The cached projects are parsed once per change of the cache file.
+        let cache_dir = ws.join("cache");
+        let write = |projects: &[ReportedProject]| {
+            let cache = GradleCache { projects: projects.to_vec(), ..GradleCache::default() };
+            write_cache(&cache_dir, GRADLE_CACHE, &cache).unwrap();
+        };
+        write(&projects);
+        let first = reported_gradle_projects(&cache_dir);
+        assert!(Arc::ptr_eq(&first, &reported_gradle_projects(&cache_dir)), "unchanged: not parsed again");
+        assert_eq!(crate::gradle_external_roots(&root, &cache_dir, &Default::default()), [billing]);
+        write(&projects[..1]);
+        assert_eq!(reported_gradle_projects(&cache_dir).len(), 1, "a new sync is read");
+        std::fs::remove_file(cache_dir.join(GRADLE_CACHE)).unwrap();
+        assert!(reported_gradle_projects(&cache_dir).is_empty());
+    }
+
    #[test]
    fn gradle_cache_replaces_tasks_per_project() {
        let tmp = tempfile::tempdir().unwrap();
@@ -378,16 +765,39 @@ mod tests {
        std::fs::write(root.join("app/build.gradle"), "apply plugin: 'java'").unwrap();
        let mut model = gradle::load(&root).unwrap();
        let cache = GradleCache {
-            hash: hash_files(&gradle::build_files(&root, &model)),
+            hash: hash_gradle_files(&gradle::build_files(&root, &model)),
            at_ms: 1.0,
            error: None,
            tasks: vec![(":app".into(), GradleTask { name: "hello".into(), group: "demo".into(), description: None })],
+            projects: [":", ":app"]
+                .iter()
+                .zip([root.clone(), root.join("app")])
+                .map(|(path, dir)| ReportedProject {
+                    path: (*path).into(),
+                    dir: dir.to_string_lossy().into_owned(),
+                    ..Default::default()
+                })
+                .collect(),
        };
        write_cache(&cache_dir, GRADLE_CACHE, &cache).unwrap();
        apply_gradle_cache(&root, &cache_dir, &mut model);
        assert_eq!(model.projects[1].tasks.len(), 1);
        assert!(model.projects[0].tasks.iter().any(|t| t.name == "wrapper"), "root keeps its defaults");
        assert!(!model.stale);
+
+        let stale_after = |script: &str| {
+            std::fs::write(root.join("app/build.gradle"), script).unwrap();
+            let mut m = gradle::load(&root).unwrap();
+            apply_gradle_cache(&root, &cache_dir, &mut m);
+            m.stale
+        };
+        assert!(!stale_after("// a note\napply   plugin: 'java'\n"), "comments and spacing don't count");
+        assert!(stale_after("apply plugin: 'groovy'"));
+        std::fs::write(root.join("app/build.gradle"), "apply plugin: 'java'").unwrap();
+        std::fs::write(root.join("gradle.properties"), "org.gradle.jvmargs=-Xmx2g").unwrap();
+        let mut m = gradle::load(&root).unwrap();
+        apply_gradle_cache(&root, &cache_dir, &mut m);
+        assert!(m.stale, "gradle.properties is watched");
    }

    #[test]
@@ -420,4 +830,25 @@ mod tests {
        assert_eq!(error_summary(text), "Failed to execute goal");
        assert_eq!(error_summary("one\nlast line\n\n"), "last line");
    }
+
+    #[cfg(unix)]
+    #[test]
+    fn maven_sync_runs_the_daemon_command_serially() {
+        use std::os::unix::fs::PermissionsExt;
+        let tmp = tempfile::tempdir().unwrap();
+        let root = tmp.path().join("p");
+        std::fs::create_dir_all(&root).unwrap();
+        std::fs::write(root.join("pom.xml"), "<project><groupId>g</groupId><artifactId>a</artifactId></project>")
+            .unwrap();
+        let launcher = tmp.path().join("fake-mvnd");
+        std::fs::write(&launcher, "#!/bin/sh\nprintf '%s\\n' \"$@\" > mvnd-args\n").unwrap();
+        std::fs::set_permissions(&launcher, std::fs::Permissions::from_mode(0o755)).unwrap();
+        let options =
+            SyncOptions { maven_command: Some(launcher.to_string_lossy().into_owned()), ..Default::default() };
+        sync_maven(&root, &tmp.path().join("cache"), &options, &CancellationToken::new(), &|_| {}).unwrap();
+        let args = std::fs::read_to_string(root.join("mvnd-args")).unwrap();
+        // `-T1` pins the daemon serial so the dependency trees stay parseable.
+        assert!(args.contains("-T1"), "args: {args}");
+        assert!(args.contains("help:effective-pom"), "args: {args}");
+    }
 }
@@ -26,12 +26,12 @@ pub fn artifacts(root: &Path, model: &BuildModel) -> Vec<WebArtifact> {
            });
        }
    }
-    if let Some(gradle) = &model.gradle {
+    for gradle in &model.gradle {
        for p in &gradle.projects {
            let script = p.build_file.as_ref().and_then(|f| fs::read_to_string(root.join(f)).ok()).unwrap_or_default();
            if p.tasks.iter().any(|t| t.name == "war") || crate::gradle::has_war_plugin(&script) {
                out.push(WebArtifact {
-                    id: format!("gradle:{}", p.path),
+                    id: gradle_artifact_id(gradle, &p.path),
                    name: p.name.clone(),
                    module: p.dir.clone(),
                    tool: "gradle".into(),
@@ -42,6 +42,14 @@ pub fn artifacts(root: &Path, model: &BuildModel) -> Vec<WebArtifact> {
    out
 }

+fn gradle_artifact_id(build: &crate::GradleModel, path: &str) -> String {
+    if build.dir.is_empty() {
+        format!("gradle:{path}")
+    } else {
+        format!("gradle:{}", serde_json::to_string(&(&build.dir, path)).unwrap())
+    }
+}
+
 pub struct WebBuild {
    pub command: String,
    pub args: Vec<String>,
@@ -150,9 +158,14 @@ pub fn build(root: &Path, model: &BuildModel, id: &str, cache: &Path) -> IdeResu
            maven_project: Some((probe, output)),
        });
    }
-    if let Some(path) = id.strip_prefix("gradle:") {
-        let g = model.gradle.as_ref().ok_or_else(|| IdeError::invalid("Choose a Gradle WAR module"))?;
-        if !artifacts(root, model).iter().any(|a| a.id == id) {
+    if let Some(legacy_path) = id.strip_prefix("gradle:") {
+        let identity = serde_json::from_str::<(String, String)>(legacy_path).ok();
+        let (g, path) = match &identity {
+            Some((dir, path)) => (model.gradle.iter().find(|g| g.dir == *dir), path.as_str()),
+            None => (model.gradle.first(), legacy_path),
+        };
+        let g = g.ok_or_else(|| IdeError::invalid("Choose a Gradle WAR module"))?;
+        if !artifacts(root, model).iter().any(|a| a.id == gradle_artifact_id(g, path)) {
            return Err(IdeError::invalid("Choose a Gradle WAR module"));
        }
        let script = cache.join("war.init.gradle");
@@ -186,6 +199,28 @@ pub fn build(root: &Path, model: &BuildModel, id: &str, cache: &Path) -> IdeResu

 #[cfg(test)]
 mod tests {
+    #[test]
+    fn independent_war_modules_have_distinct_ids_and_build_in_their_own_directory() {
+        let temp = tempfile::tempdir().unwrap();
+        let root = temp.path();
+        for dir in ["a", "b"] {
+            std::fs::create_dir(root.join(dir)).unwrap();
+            std::fs::write(root.join(dir).join("build.gradle"), "plugins { id 'war' }").unwrap();
+        }
+        let settings = ide_core::settings::GradleSettings {
+            linked_projects: Some(vec!["a".into(), "b".into()]),
+            ..Default::default()
+        };
+        let model = crate::load_linked(root, &root.join("cache"), None, &Default::default(), &settings);
+        let artifacts = super::artifacts(root, &model);
+        assert_eq!(artifacts.len(), 2);
+        assert_ne!(artifacts[0].id, artifacts[1].id);
+        for (artifact, dir) in artifacts.iter().zip(["a", "b"]) {
+            let plan = super::build(root, &model, &artifact.id, &root.join(format!("cache/{dir}"))).unwrap();
+            assert_eq!(plan.cwd, dir);
+        }
+        assert_eq!(super::build(root, &model, "gradle::", &root.join("legacy")).unwrap().cwd, "a");
+    }
    use super::*;
    #[test]
    fn maven_war_modules_use_resolved_artifact_file() {
@@ -18,5 +18,8 @@ tokio-util.workspace = true
 [dev-dependencies]
 tempfile.workspace = true

+[target.'cfg(unix)'.dependencies]
+libc = "0.2"
+
 [target.'cfg(windows)'.dependencies]
-windows-sys = { version = "0.61", features = ["Win32_Globalization", "Win32_System_Registry", "Win32_Foundation"] }
+windows-sys = { version = "0.61", features = ["Win32_Globalization", "Win32_Security", "Win32_System_Registry", "Win32_Foundation", "Win32_System_Diagnostics_ToolHelp", "Win32_System_Threading"] }
@@ -36,12 +36,21 @@ pub enum IdeEvent {
        base_version: u32,
        version: u32,
        changes: Vec<TextChange>,
+        /// Part of a grouped transaction; the editor must not record a file-local undo.
+        #[serde(default)]
+        #[specta(optional)]
+        workspace_edit: bool,
    },
    /// A document's dirty flag changed (saved / modified externally).
    DocDirty {
        doc: DocId,
        dirty: bool,
    },
+    /// A complete workspace edit can be undone as one operation.
+    WorkspaceEditApplied {
+        id: u32,
+        paths: Vec<crate::IpcPath>,
+    },
    /// An open document's language changed (Settings › File Types, Override File
    /// Type), or its UI mode (a framework's root marker appeared or went).
    DocLanguage {
@@ -82,6 +91,12 @@ pub enum IdeEvent {
        status: ServerStatus,
        message: Option<String>,
    },
+    /// A running server lacks a capability; the UI offers the managed tool as a replacement.
+    LanguageServerWarning {
+        name: String,
+        message: String,
+        install_tool: String,
+    },
    /// A stopped language server left the project's list (disabled in settings, or a
    /// fallback that a preferred server took over from again).
    LanguageServerRemoved {
@@ -2,6 +2,18 @@
 //! treats as nonexistent — hidden from the project view and navigation, never
 //! indexed or searched, never offered as unversioned changes.

+use std::path::Path;
+
+/// Whether `dir` lies in a Git (or jj) working tree: it or an ancestor holds `.git` / `.jj`.
+///
+/// Walkers pass it to `ignore::WalkBuilder::require_git`: inside a repository, `.gitignore`
+/// rules then stop at a nested repository's root as in git, so an outer repository's
+/// `.gitignore` does not hide a project that is its own repository. A folder outside any
+/// repository still honours its `.gitignore`.
+pub fn inside_git_repo(dir: &Path) -> bool {
+    dir.ancestors().any(|d| d.join(".git").exists() || d.join(".jj").exists())
+}
+
 /// IDEA's default list, plus `.jj` and the Windows shell files.
 pub const DEFAULT_IGNORED_NAMES: &[&str] = &[
    "*.pyc",
@@ -103,4 +115,15 @@ mod tests {
        assert!(m.is_ignored_path("pkg/__pycache__/mod.cpython-312.pyc"));
        assert!(!m.is_ignored_path("src/main.rs"));
    }
+
+    #[test]
+    fn finds_the_repository_at_or_above_a_directory() {
+        let dir = tempfile::tempdir().unwrap();
+        let sub = dir.path().join("a/b");
+        std::fs::create_dir_all(&sub).unwrap();
+        assert!(!inside_git_repo(&sub));
+        std::fs::create_dir(dir.path().join("a/.git")).unwrap();
+        assert!(inside_git_repo(&sub));
+        assert!(inside_git_repo(&dir.path().join("a")));
+    }
 }
@@ -36,6 +36,23 @@ impl Default for InspectionSettings {
    }
 }

+impl InspectionSettings {
+    /// Overrides of the profile in effect; `Default`'s when `profile` names none that exists.
+    pub fn active(&self) -> &BTreeMap<String, InspectionOverride> {
+        let custom = |level: &str, key: &str| match level {
+            "ide" => self.ide_profiles.get(key),
+            "project" => self.project_profiles.get(key),
+            _ => None,
+        };
+        match self.profile.as_str() {
+            "project" => &self.project,
+            id => {
+                id.split_once(':').and_then(|(level, key)| custom(level, key)).map_or(&self.default, |p| &p.overrides)
+            }
+        }
+    }
+}
+
 /// A named profile made with Copy.
 #[derive(Clone, Debug, Default, PartialEq, Eq, Serialize, Deserialize, Type)]
 #[serde(default, rename_all = "camelCase")]
@@ -111,4 +128,20 @@ mod tests {
        let back: InspectionSettings = serde_json::from_str(&serde_json::to_string(&s).unwrap()).unwrap();
        assert_eq!(back, s);
    }
+
+    #[test]
+    fn active_profile_falls_back_to_default() {
+        let off = |id: &str| {
+            BTreeMap::from([(id.to_owned(), InspectionOverride { enabled: Some(false), ..Default::default() })])
+        };
+        let mut s = InspectionSettings { default: off("a"), project: off("b"), ..Default::default() };
+        s.ide_profiles.insert("strict".into(), CustomInspectionProfile { name: "Strict".into(), overrides: off("c") });
+        assert!(s.active().contains_key("a"));
+        s.profile = "project".into();
+        assert!(s.active().contains_key("b"));
+        s.profile = "ide:strict".into();
+        assert!(s.active().contains_key("c"));
+        s.profile = "project:gone".into();
+        assert!(s.active().contains_key("a"));
+    }
 }
@@ -0,0 +1,25 @@
+//! Capabilities needed by the JVM hosting Java language-server bundles.
+
+use std::path::Path;
+
+/// jdtls' javac bundle, java-debug / hot code replace, and Lombok / Gradle tooling.
+const BUNDLE_MODULES: &[&str] = &["jdk.compiler", "jdk.jdi", "jdk.unsupported"];
+
+/// Require a full JDK, including the modules used by jdtls and its bundles.
+/// Temurin JREs can list the build JDK's modules in `release` even when the runtime
+/// image omits them, so module metadata alone does not establish suitability.
+pub fn supports_java_bundles(home: &Path) -> bool {
+    let Ok(release) = std::fs::read_to_string(home.join("release")) else { return false };
+    let property =
+        |key: &str| release.lines().find_map(|line| line.trim().strip_prefix(key)).map(|v| v.trim().trim_matches('"'));
+    let javac = if cfg!(windows) { "javac.exe" } else { "javac" };
+    if property("IMAGE_TYPE=").is_some_and(|image| image.eq_ignore_ascii_case("jre"))
+        || !home.join("bin").join(javac).is_file()
+    {
+        return false;
+    }
+    match property("MODULES=") {
+        Some(modules) => BUNDLE_MODULES.iter().all(|required| modules.split_whitespace().any(|m| m == *required)),
+        None => BUNDLE_MODULES.iter().all(|m| home.join("jmods").join(format!("{m}.jmod")).is_file()),
+    }
+}
@@ -11,6 +11,7 @@ pub mod ids;
 pub mod ignored;
 pub mod inspection_settings;
 pub mod ipc_path;
+pub mod java_runtime;
 pub mod jsonc;
 pub mod output_encoding;
 pub mod process;
@@ -23,6 +24,7 @@ pub mod text;
 pub mod tool_path;
 pub mod version_managers;
 pub mod workflow_settings;
+pub mod wsl;

 pub use error::{IdeError, IdeResult};
 pub use event::{EventSink, IdeEvent, NullSink, SharedSink};
@@ -13,7 +13,10 @@
 //!   they fork get them too (`spring-boot:run`, Surefire, `bootRun`, test workers).
 //!   Each JVM then reports "Picked up JAVA_TOOL_OPTIONS: …" on stderr (which a build tool
 //!   may copy to its stdout); that line is hidden again ([`NoticeFilter`]). `file.encoding` is left alone there: it would change
-//!   how a build reads sources that declare no encoding.
+//!   how a build reads sources that declare no encoding. The application JVMs a build
+//!   forks get `file.encoding=UTF-8` for a UTF-8 console instead, through the build's own
+//!   options: `-Dspring-boot.run.jvmArguments` for Maven `spring-boot:run`, an init script
+//!   ([`GRADLE_FILE_ENCODING_SCRIPT`]) for Gradle `JavaExec` tasks (`bootRun`, `run`).
 //! - Python: `PYTHONIOENCODING`.

 use std::collections::BTreeMap;
@@ -75,16 +78,34 @@ fn encoding_for_code_page(cp: u32) -> Option<&'static encoding_rs::Encoding> {
 const STD_PROPERTIES: &[&str] = &["stdout.encoding", "stderr.encoding", "sun.stdout.encoding", "sun.stderr.encoding"];
 const FILE_ENCODING: &str = "file.encoding";
 const TOOL_OPTIONS: &str = "JAVA_TOOL_OPTIONS";
+const SPRING_BOOT_JVM_ARGS: &str = "-Dspring-boot.run.jvmArguments=";

 /// Build tools and launcher scripts that run on (and may fork) JVMs.
-const JVM_TOOLS: &[&str] =
-    &["mvn", "mvnw", "mvnd", "gradle", "gradlew", "sbt", "ant", "kotlin", "kotlinc", "groovy", "scala", "jbang"];
+const JVM_TOOLS: &[&str] = &["sbt", "ant", "kotlin", "kotlinc", "groovy", "scala", "jbang"];
+const MAVEN: &[&str] = &["mvn", "mvnw", "mvnd"];
+const GRADLE: &[&str] = &["gradle", "gradlew"];
+
+/// Gradle init script giving the `JavaExec` tasks (`bootRun`, `run`, custom ones) a UTF-8
+/// default charset before the build configures them, so the build can override it.
+/// Gradle's own JVM and the compiler's source encoding are untouched.
+pub const GRADLE_FILE_ENCODING_SCRIPT: &str = "\
+// Written by OpenIDEA: a UTF-8 default charset for applications run by Gradle, as the Run console decodes UTF-8.
+allprojects {
+    tasks.withType(JavaExec).configureEach {
+        defaultCharacterEncoding = 'UTF-8'
+    }
+}
+";

 /// What a launch needs: `-D` options to put first on a `java` command line,
 /// environment variables to set, and the notice line its JVMs print because of them.
 #[derive(Debug, Default, PartialEq, Eq)]
 pub struct EncodingFix {
    pub java_args: Vec<String>,
+    /// The build tool's arguments, rewritten to pass options to the JVM it forks.
+    pub args: Option<Vec<String>>,
+    /// Gradle: pass [`GRADLE_FILE_ENCODING_SCRIPT`] with `--init-script`.
+    pub gradle_init_script: bool,
    pub env: Vec<(String, String)>,
    /// "Picked up JAVA_TOOL_OPTIONS: …" for a variable set here alone, to drop from the output.
    pub notice: Option<String>,
@@ -116,6 +137,8 @@ fn options(properties: &[&str], encoding: &str) -> Vec<String> {
 #[derive(Clone, Copy, PartialEq, Eq)]
 enum Kind {
    Java,
+    Maven,
+    Gradle,
    JvmTool,
    Python,
    Other,
@@ -125,6 +148,10 @@ fn kind(program: &str) -> Kind {
    let name = program_name(program);
    if name == "java" || name == "javaw" {
        Kind::Java
+    } else if MAVEN.contains(&name.as_str()) {
+        Kind::Maven
+    } else if GRADLE.contains(&name.as_str()) {
+        Kind::Gradle
    } else if JVM_TOOLS.contains(&name.as_str()) {
        Kind::JvmTool
    } else if is_python(&name) {
@@ -193,7 +220,17 @@ fn fix_kind(
                out.java_args.push(format!("-D{FILE_ENCODING}=UTF-8"));
            }
        }
-        (Kind::Java | Kind::JvmTool, _) => {
+        (Kind::Java | Kind::Maven | Kind::Gradle | Kind::JvmTool, _) => {
+            if let Some(args) = args
+                && is_utf8(encoding)
+                && !sets(&tool_options, &[FILE_ENCODING])
+            {
+                match kind {
+                    Kind::Maven => out.args = spring_boot_file_encoding(args),
+                    Kind::Gradle => out.gradle_init_script = true,
+                    _ => {}
+                }
+            }
            if !sets(&tool_options, STD_PROPERTIES) {
                let added = options(STD_PROPERTIES, encoding).join(" ");
                let value = match tool_options.trim() {
@@ -214,14 +251,42 @@ fn fix_kind(
    out
 }

-/// `vmArgs` of a launch by java-debug, which decodes the JVM's output as `encoding`
-/// (its launch attribute, UTF-8 when unset) and sets `file.encoding` itself.
-pub fn java_debug_vm_args(vm_args: &str, encoding: Option<&str>, windows: bool) -> Option<String> {
-    let encoding = encoding.map(str::trim).filter(|e| !e.is_empty()).unwrap_or("UTF-8");
-    if (!windows && is_utf8(encoding)) || sets(vm_args, STD_PROPERTIES) {
+fn spring_boot_file_encoding(args: &[String]) -> Option<Vec<String>> {
+    if !args.iter().any(|a| a == "spring-boot:run" || (a.contains(":spring-boot-maven-plugin:") && a.ends_with(":run")))
+    {
        return None;
    }
-    let added = options(STD_PROPERTIES, encoding).join(" ");
+    let option = format!("-D{FILE_ENCODING}=UTF-8");
+    let mut out = args.to_vec();
+    match out.iter_mut().rfind(|a| a.starts_with(SPRING_BOOT_JVM_ARGS)) {
+        Some(own) if sets(own, &[FILE_ENCODING]) => return None,
+        Some(own) => {
+            if own.len() > SPRING_BOOT_JVM_ARGS.len() {
+                own.push(' ');
+            }
+            own.push_str(&option);
+        }
+        None => out.push(format!("{SPRING_BOOT_JVM_ARGS}{option}")),
+    }
+    Some(out)
+}
+
+/// `vmArgs` of a launch by java-debug, which decodes the JVM's output as `encoding`
+/// (its launch attribute, UTF-8 when unset). java-debug sets `file.encoding` only
+/// when that attribute is nonblank; use the same defaults and user overrides as [`fix`].
+pub fn java_debug_vm_args(
+    vm_args: &str,
+    vars: &BTreeMap<String, String>,
+    inherited: impl Fn(&str) -> Option<String>,
+    encoding: Option<&str>,
+    windows: bool,
+) -> Option<String> {
+    let encoding = encoding.map(str::trim).filter(|e| !e.is_empty()).unwrap_or("UTF-8");
+    let added = fix_kind(Kind::Java, Some(&[vm_args.to_owned()]), vars, inherited, encoding, windows).java_args;
+    if added.is_empty() {
+        return None;
+    }
+    let added = added.join(" ");
    Some(match vm_args.trim() {
        "" => added,
        own => format!("{own} {added}"),
@@ -427,6 +492,64 @@ mod tests {
        assert_eq!(run("python3", &[], &[], "GBK", false).env, [("PYTHONIOENCODING".to_owned(), "GBK".to_owned())]);
    }

+    #[test]
+    fn spring_boot_run_forks_get_a_utf8_default_charset() {
+        let boot = |args: &[&str], env: &[(&str, &str)]| run("mvn.cmd", args, env, "UTF-8", true).args;
+        let utf8 = "-Dspring-boot.run.jvmArguments=-Dfile.encoding=UTF-8";
+        assert_eq!(boot(&["spring-boot:run"], &[]).unwrap(), ["spring-boot:run", utf8]);
+        let plugin = "org.springframework.boot:spring-boot-maven-plugin:3.2.0:run";
+        assert_eq!(boot(&["-pl", "app", plugin], &[]).unwrap(), ["-pl", "app", plugin, utf8]);
+        // The user's VM options are kept; their own `file.encoding` wins.
+        assert_eq!(
+            boot(&["spring-boot:run", "-Dspring-boot.run.jvmArguments=-Xmx1g \"-Da=b c\""], &[]).unwrap(),
+            ["spring-boot:run", "-Dspring-boot.run.jvmArguments=-Xmx1g \"-Da=b c\" -Dfile.encoding=UTF-8"]
+        );
+        assert_eq!(boot(&["spring-boot:run", "-Dspring-boot.run.jvmArguments="], &[]).unwrap()[1], utf8);
+        assert!(boot(&["spring-boot:run", "-Dspring-boot.run.jvmArguments=-Dfile.encoding=GBK"], &[]).is_none());
+        assert!(boot(&["spring-boot:run"], &[(TOOL_OPTIONS, "-Dfile.encoding=GBK")]).is_none());
+        // Other goals and tools, other consoles, and other platforms are left alone.
+        assert!(boot(&["package"], &[]).is_none());
+        assert!(run("mvn", &["spring-boot:run"], &[], "GBK", true).args.is_none());
+        assert!(run("mvn", &["spring-boot:run"], &[], "UTF-8", false).args.is_none());
+    }
+
+    #[test]
+    fn forked_application_jvms_get_a_utf8_default_charset() {
+        // Reported: a Spring Boot app run by the build on Chinese Windows (JDK 8–17, GBK default).
+        for (tool, args) in [
+            ("C:\\p\\gradlew.bat", &["bootRun"][..]),
+            ("gradle", &[":app:run"]),
+            ("mvnw.cmd", &["spring-boot:run"]),
+            ("mvnd", &["org.springframework.boot:spring-boot-maven-plugin:2.7.18:run"]),
+        ] {
+            let f = run(tool, args, &[], "UTF-8", true);
+            let gradle = tool.contains("gradle");
+            assert_eq!(f.gradle_init_script, gradle, "{tool}");
+            assert_eq!(f.args.is_some(), !gradle, "{tool}");
+            // The build tool's own JVM keeps its default charset.
+            assert!(!tool_env(&f).unwrap().contains("file.encoding"), "{tool}");
+            // The user's choice, a GBK console and other platforms are left alone.
+            let own = run(tool, args, &[(TOOL_OPTIONS, "-Dfile.encoding=GBK")], "UTF-8", true);
+            assert!(!own.gradle_init_script && own.args.is_none(), "{tool}");
+            let gbk = run(tool, args, &[], "GBK", true);
+            assert!(!gbk.gradle_init_script && gbk.args.is_none(), "{tool}");
+            assert_eq!(run(tool, args, &[], "UTF-8", false), EncodingFix::default(), "{tool}");
+        }
+        // Shell command lines can't take arguments; other JVM tools fork no application.
+        assert!(!fix_command_line("gradlew bootRun", &BTreeMap::new(), |_| None, "UTF-8", true).gradle_init_script);
+        let sbt = run("sbt", &["run"], &[], "UTF-8", true);
+        assert!(!sbt.gradle_init_script && sbt.args.is_none());
+    }
+
+    #[test]
+    fn gradle_script_respects_the_builds_own_file_encoding() {
+        let s = GRADLE_FILE_ENCODING_SCRIPT;
+        assert!(s.contains("tasks.withType(JavaExec).configureEach"), "{s}");
+        assert!(s.contains("defaultCharacterEncoding = 'UTF-8'"), "{s}");
+        assert!(!s.contains("doFirst"), "the build must be able to override the default: {s}");
+        assert!(!s.contains("withType(Test)") && !s.contains("JavaCompile"), "{s}");
+    }
+
    #[test]
    fn shell_command_lines_get_variables_from_their_first_word() {
        let line = |l: &str| fix_command_line(l, &BTreeMap::new(), |_| None, "UTF-8", true);
@@ -446,12 +569,53 @@ mod tests {

    #[test]
    fn java_debug_launches_write_what_java_debug_decodes() {
-        assert_eq!(java_debug_vm_args("", None, true).as_deref(), Some(TOOL_UTF8));
-        assert_eq!(java_debug_vm_args("-Xmx1g", Some(""), true), Some(format!("-Xmx1g {TOOL_UTF8}")));
-        assert_eq!(java_debug_vm_args("", Some("GBK"), true).unwrap().split(' ').next(), Some("-Dstdout.encoding=GBK"));
-        assert_eq!(java_debug_vm_args("-Dstdout.encoding=GBK", None, true), None);
-        assert_eq!(java_debug_vm_args("-Xmx1g", None, false), None);
-        assert!(java_debug_vm_args("", Some("GBK"), false).is_some());
+        let debug =
+            |args: &str, encoding, windows| java_debug_vm_args(args, &BTreeMap::new(), |_| None, encoding, windows);
+        for encoding in [None, Some(""), Some("  "), Some("UTF-8"), Some("utf8")] {
+            let streams = encoding.filter(|e| !e.trim().is_empty()).unwrap_or("UTF-8");
+            let utf8 = format!("{} -Dfile.encoding=UTF-8", options(STD_PROPERTIES, streams).join(" "));
+            assert_eq!(debug("", encoding, true), Some(utf8.clone()));
+            assert_eq!(debug("-Xmx1g", encoding, true), Some(format!("-Xmx1g {utf8}")));
+            assert_eq!(debug("-Xmx1g", encoding, false), None);
+        }
+        for windows in [true, false] {
+            assert_eq!(debug("", Some("GBK"), windows), Some(options(STD_PROPERTIES, "GBK").join(" ")));
+        }
+    }
+
+    #[test]
+    fn java_debug_preserves_user_options_independently() {
+        let debug = |args: &str| java_debug_vm_args(args, &BTreeMap::new(), |_| None, None, true);
+        assert_eq!(debug("-Dfile.encoding=GBK"), Some(format!("-Dfile.encoding=GBK {TOOL_UTF8}")));
+        for property in STD_PROPERTIES {
+            let args = format!("-D{property}=GBK");
+            assert_eq!(debug(&args), Some(format!("{args} -Dfile.encoding=UTF-8")));
+            assert_eq!(debug(&format!("{args} -Dfile.encoding=GBK")), None);
+        }
+        for key in ["JDK_JAVA_OPTIONS", TOOL_OPTIONS] {
+            for (own, expected) in [
+                ("-Dfile.encoding=GBK", Some(TOOL_UTF8.to_owned())),
+                ("-Dstdout.encoding=GBK", Some("-Dfile.encoding=UTF-8".to_owned())),
+                ("-Dstdout.encoding=GBK -Dfile.encoding=GBK", None),
+            ] {
+                assert_eq!(java_debug_vm_args("", &vars(&[(key, own)]), |_| None, None, true), expected);
+                assert_eq!(
+                    java_debug_vm_args("", &BTreeMap::new(), |k| (k == key).then(|| own.to_owned()), None, true),
+                    expected
+                );
+            }
+            // A launch environment value overrides the inherited one, as in Run.
+            assert_eq!(
+                java_debug_vm_args(
+                    "",
+                    &vars(&[(key, "")]),
+                    |k| (k == key).then(|| "-Dfile.encoding=GBK".into()),
+                    None,
+                    true
+                ),
+                Some(format!("{TOOL_UTF8} -Dfile.encoding=UTF-8"))
+            );
+        }
    }

    fn filtered(chunks: &[&str]) -> String {
@@ -1,8 +1,11 @@
 //! Child-process helpers shared by every crate that spawns tools.

 use std::ffi::{OsStr, OsString};
-use std::process::Command;
+#[cfg(windows)]
+use std::process::Stdio;
+use std::process::{Child, Command};
 use std::sync::{Arc, RwLock};
+use std::time::Duration;

 /// Windows `CREATE_NO_WINDOW` creation flag, for call sites that combine it
 /// with other flags (and then call [`host_env`] themselves). Prefer [`prepare`] otherwise.
@@ -25,18 +28,195 @@ pub fn prepare(cmd: &mut Command) -> &mut Command {
    host_env(cmd)
 }

+/// Starts the child as the leader of its own process group on Unix, so [`kill_tree`] and
+/// [`terminate_tree`] reach what it starts in turn (`gh` → `git`, `npm` → `node`, `mvnw` →
+/// the JVM). A no-op elsewhere: on Windows the tree is found from the child's process id.
+pub fn own_group(cmd: &mut Command) -> &mut Command {
+    #[cfg(unix)]
+    {
+        use std::os::unix::process::CommandExt;
+        cmd.process_group(0);
+    }
+    cmd
+}
+
+/// Kills the child and everything it started, then reaps it.
+///
+/// - Unix: `SIGKILL` to its process group, so spawn it with [`own_group`].
+/// - Windows: `taskkill /T /F`, which walks the tree from the child's process id, then a
+///   wait for what the child started to be gone.
+pub fn kill_tree(child: &mut Child) {
+    #[cfg(unix)]
+    signal_group(child, libc::SIGKILL);
+    #[cfg(windows)]
+    taskkill_tree_of(child.id());
+    let _ = child.kill();
+    let _ = child.wait();
+}
+
+/// [`kill_tree`] for a child known by its process id (a `tokio` child): `SIGKILL` to its
+/// process group (spawn it with [`own_group`]) or `taskkill /T /F` and a wait for what the
+/// child started to be gone. Call it before the child is reaped, so the id still names it.
+/// The child itself is left to its owner to kill and reap.
+pub fn kill_tree_of(pid: u32) {
+    #[cfg(unix)]
+    if let Ok(pid) = libc::pid_t::try_from(pid) {
+        // SAFETY: plain syscall; see `signal_group`.
+        unsafe {
+            libc::kill(-pid, libc::SIGKILL);
+        }
+    }
+    #[cfg(windows)]
+    taskkill_tree_of(pid);
+    #[cfg(not(any(unix, windows)))]
+    let _ = pid;
+}
+
+/// [`kill_tree`] that first asks the group to exit: `SIGTERM`, then `grace`, then `SIGKILL`.
+/// Git removes its `index.lock` on `SIGTERM`, where `SIGKILL` leaves it behind and the next
+/// git command fails. Windows has no such signal to send from outside the child's console,
+/// so there it is [`kill_tree`].
+pub fn terminate_tree(child: &mut Child, grace: Duration) {
+    #[cfg(unix)]
+    {
+        signal_group(child, libc::SIGTERM);
+        // Sleep rather than `try_wait`: the child stays unreaped, so its process id (and the
+        // group id) cannot be reused before the `SIGKILL` below.
+        std::thread::sleep(grace);
+    }
+    #[cfg(not(unix))]
+    let _ = grace;
+    kill_tree(child);
+}
+
+#[cfg(unix)]
+fn signal_group(child: &Child, signal: libc::c_int) {
+    if let Ok(pid) = libc::pid_t::try_from(child.id()) {
+        // SAFETY: plain syscall. The child is not reaped yet, so `-pid` is still its group (or
+        // no group at all when it was not spawned with `own_group`, and the call fails).
+        unsafe {
+            libc::kill(-pid, signal);
+        }
+    }
+}
+
+/// How long killing a tree waits for the processes the child started to be gone.
+#[cfg(windows)]
+const TREE_EXIT_WAIT: Duration = Duration::from_secs(5);
+
+/// `taskkill /T /F` from `pid`, then waits (up to [`TREE_EXIT_WAIT`]) until what the child
+/// started is gone: termination is asynchronous, and until a process is gone the files it
+/// holds open can't be opened or deleted. The child itself is left to its owner to reap.
+#[cfg(windows)]
+fn taskkill_tree_of(pid: u32) {
+    let started = windows_tree::descendants(pid);
+    let mut taskkill = Command::new("taskkill");
+    prepare(&mut taskkill)
+        .args(["/T", "/F", "/PID", &pid.to_string()])
+        .stdin(Stdio::null())
+        .stdout(Stdio::null())
+        .stderr(Stdio::null());
+    let _ = taskkill.status();
+    windows_tree::wait_all(&started, TREE_EXIT_WAIT);
+}
+
+#[cfg(windows)]
+mod windows_tree {
+    use std::collections::HashSet;
+    use std::os::windows::io::{AsRawHandle, FromRawHandle, OwnedHandle};
+    use std::time::{Duration, Instant};
+    use windows_sys::Win32::Foundation::{FILETIME, INVALID_HANDLE_VALUE};
+    use windows_sys::Win32::System::Diagnostics::ToolHelp::{
+        CreateToolhelp32Snapshot, PROCESSENTRY32W, Process32FirstW, Process32NextW, TH32CS_SNAPPROCESS,
+    };
+    use windows_sys::Win32::System::Threading::{
+        GetProcessTimes, OpenProcess, PROCESS_QUERY_LIMITED_INFORMATION, PROCESS_SYNCHRONIZE, WaitForSingleObject,
+    };
+
+    /// Every process `root` started, directly or not, opened so it can be waited for. A
+    /// parent's id is reused once it is gone, so a process counts only if it started after
+    /// its parent.
+    pub(super) fn descendants(root: u32) -> Vec<OwnedHandle> {
+        let Some(root_started) = open(root).as_ref().and_then(started) else { return Vec::new() };
+        let processes = processes();
+        let mut seen = HashSet::from([root]);
+        let mut parents = vec![(root, root_started)];
+        let mut found = Vec::new();
+        while let Some((parent, parent_started)) = parents.pop() {
+            for &(pid, ppid) in &processes {
+                if ppid != parent || !seen.insert(pid) {
+                    continue;
+                }
+                let Some(handle) = open(pid) else { continue };
+                if let Some(at) = started(&handle).filter(|&at| at >= parent_started) {
+                    parents.push((pid, at));
+                    found.push(handle);
+                }
+            }
+        }
+        found
+    }
+
+    pub(super) fn wait_all(processes: &[OwnedHandle], within: Duration) {
+        let until = Instant::now() + within;
+        for process in processes {
+            let left = until.saturating_duration_since(Instant::now());
+            // SAFETY: a live process handle opened with SYNCHRONIZE access.
+            unsafe { WaitForSingleObject(process.as_raw_handle(), left.as_millis().min(u32::MAX as u128 - 1) as u32) };
+        }
+    }
+
+    /// (process id, parent process id) of every running process.
+    fn processes() -> Vec<(u32, u32)> {
+        let mut out = Vec::new();
+        // SAFETY: a snapshot handle owned here and an entry sized as the API requires.
+        unsafe {
+            let snapshot = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
+            if snapshot.is_null() || snapshot == INVALID_HANDLE_VALUE {
+                return out;
+            }
+            let snapshot = OwnedHandle::from_raw_handle(snapshot);
+            let mut entry = PROCESSENTRY32W { dwSize: size_of::<PROCESSENTRY32W>() as u32, ..Default::default() };
+            let mut more = Process32FirstW(snapshot.as_raw_handle(), &mut entry);
+            while more != 0 {
+                out.push((entry.th32ProcessID, entry.th32ParentProcessID));
+                more = Process32NextW(snapshot.as_raw_handle(), &mut entry);
+            }
+        }
+        out
+    }
+
+    fn open(pid: u32) -> Option<OwnedHandle> {
+        // SAFETY: plain call; a non-null result is a process handle owned by the caller.
+        let handle = unsafe { OpenProcess(PROCESS_SYNCHRONIZE | PROCESS_QUERY_LIMITED_INFORMATION, 0, pid) };
+        // SAFETY: as above.
+        (!handle.is_null()).then(|| unsafe { OwnedHandle::from_raw_handle(handle) })
+    }
+
+    /// When the process started, in 100 ns ticks since 1601.
+    fn started(process: &OwnedHandle) -> Option<u64> {
+        let (mut created, mut exited, mut kernel, mut user) =
+            (FILETIME::default(), FILETIME::default(), FILETIME::default(), FILETIME::default());
+        // SAFETY: a live process handle opened with query access; four out-parameters.
+        let ok = unsafe { GetProcessTimes(process.as_raw_handle(), &mut created, &mut exited, &mut kernel, &mut user) };
+        (ok != 0).then(|| (u64::from(created.dwHighDateTime) << 32) | u64::from(created.dwLowDateTime))
+    }
+}
+
 /// Gives `cmd` the host's environment back when the IDE runs from an AppImage. `AppRun` and
 /// its hooks point `LD_LIBRARY_PATH`, `PATH`, `XDG_DATA_DIRS`, `GIO_MODULE_DIR`, `GTK_PATH`,
 /// `GST_PLUGIN_*`, ... into the mounted image for the IDE itself; a host program that
 /// inherits them loads the image's (older) libraries and plugins next to its own, e.g.
 /// `curl: symbol lookup error ... nghttp2_...`. The IDE process keeps its environment
 /// (WebKit and GTK still need it). Then applies the [`set_env_overlay`] variables and
-/// those of a manual HTTP proxy ([`crate::proxy_settings::ProxySettings::child_env`]).
-/// Variables the call site has already set are kept. A no-op outside an AppImage
-/// without an overlay.
+/// those of a manual HTTP proxy ([`crate::proxy_settings::ProxySettings::child_env`]),
+/// and the login shell's variables this process lacks ([`shell_env`]: an app started from
+/// Finder/Dock doesn't have what rc files export, such as `GOPATH`, `JAVA_HOME` or
+/// `MAVEN_OPTS`). Variables the call site has already set are kept.
 pub fn host_env(cmd: &mut Command) -> &mut Command {
    let fixes = child_env_changes();
-    if fixes.is_empty() {
+    let shell: Vec<_> = shell_env().collect();
+    if fixes.is_empty() && shell.is_empty() {
        return cmd;
    }
    let explicit: Vec<OsString> = cmd.get_envs().map(|(k, _)| k.to_owned()).collect();
@@ -46,6 +226,9 @@ pub fn host_env(cmd: &mut Command) -> &mut Command {
            None => cmd.env_remove(key),
        };
    }
+    for (key, value) in shell.into_iter().filter(|(k, _)| !explicit.contains(k)) {
+        cmd.env(key, value);
+    }
    cmd
 }

@@ -62,12 +245,13 @@ pub fn host_vars() -> impl Iterator<Item = (OsString, OsString)> {
    apply_changes(std::env::vars_os().collect(), &child_env_changes()).into_iter()
 }

-/// [`std::env::var_os`] as a child should see it (see [`host_env`]).
+/// [`std::env::var_os`] as a child should see it (see [`host_env`]), the login shell's value
+/// included when this process lacks the variable.
 pub fn host_var_os(key: impl AsRef<OsStr>) -> Option<OsString> {
    let key = key.as_ref();
    match child_env_changes().into_iter().find(|(k, _)| k == key) {
        Some((_, fixed)) => fixed,
-        None => std::env::var_os(key),
+        None => std::env::var_os(key).or_else(|| shell_env().find(|(k, _)| k == key).map(|(_, v)| v)),
    }
 }

@@ -245,10 +429,7 @@ pub fn find_executable(name: &str, search: &OsStr) -> Option<std::path::PathBuf>
 #[cfg(windows)]
 pub fn user_path() -> Option<OsString> {
    use windows_sys::Win32::Foundation::ERROR_SUCCESS;
-    use windows_sys::Win32::System::Registry::{
-        HKEY, HKEY_CURRENT_USER, KEY_READ, RRF_RT_REG_EXPAND_SZ, RRF_RT_REG_SZ, RegCloseKey, RegGetValueW,
-        RegOpenKeyExW,
-    };
+    use windows_sys::Win32::System::Registry::{HKEY, HKEY_CURRENT_USER, KEY_READ, RegCloseKey, RegOpenKeyExW};

    fn wide(s: &str) -> Vec<u16> {
        s.encode_utf16().chain(std::iter::once(0)).collect()
@@ -259,45 +440,53 @@ pub fn user_path() -> Option<OsString> {
        if RegOpenKeyExW(HKEY_CURRENT_USER, wide("Environment").as_ptr(), 0, KEY_READ, &mut key) != ERROR_SUCCESS {
            return None;
        }
-        let read = || {
-            // Only `Path`; `REG_EXPAND_SZ` is accepted so `%USERPROFILE%\…` entries expand.
-            let mut kind = 0u32;
-            let mut len = 0u32;
-            let name = wide("Path");
-            let status = RegGetValueW(
-                key,
-                std::ptr::null(),
-                name.as_ptr(),
-                RRF_RT_REG_SZ | RRF_RT_REG_EXPAND_SZ,
-                &mut kind,
-                std::ptr::null_mut(),
-                &mut len,
-            );
-            if status != ERROR_SUCCESS || len == 0 {
-                return None;
-            }
-            let mut buf = vec![0u16; (len as usize).div_ceil(2)];
-            let status = RegGetValueW(
-                key,
-                std::ptr::null(),
-                name.as_ptr(),
-                RRF_RT_REG_SZ | RRF_RT_REG_EXPAND_SZ,
-                &mut kind,
-                buf.as_mut_ptr() as *mut _,
-                &mut len,
-            );
-            if status != ERROR_SUCCESS {
-                return None;
-            }
-            let text = String::from_utf16_lossy(&buf);
-            Some(text.trim_end_matches('\0').to_owned())
-        };
-        let value = read();
+        let value = read_registry_string(key, &wide("Path"));
        RegCloseKey(key);
        value.filter(|v| !v.trim().is_empty()).map(OsString::from)
    }
 }

+/// The string of value `name` under open `key`: `REG_SZ` as-is, `REG_EXPAND_SZ` expanded
+/// against the current environment. `None` when the value is missing or unreadable.
+///
+/// A `REG_EXPAND_SZ` value's first size query reports the unexpanded size, so a value
+/// that grows when expanded is re-read at the size the failed call reports. And the
+/// terminating NUL can leak into the read buffer with a stray UTF-16 unit behind it —
+/// seen with a `REG_EXPAND_SZ` user `Path`, where it made `env::set_var("PATH", …)`
+/// panic with "strings passed to WinAPI cannot contain NULs" — so the text is cut at
+/// the first NUL, not just stripped of trailing ones.
+#[cfg(windows)]
+fn read_registry_string(key: windows_sys::Win32::System::Registry::HKEY, name: &[u16]) -> Option<String> {
+    use windows_sys::Win32::Foundation::{ERROR_MORE_DATA, ERROR_SUCCESS};
+    use windows_sys::Win32::System::Registry::{RRF_RT_REG_EXPAND_SZ, RRF_RT_REG_SZ, RegGetValueW};
+
+    const FLAGS: u32 = RRF_RT_REG_SZ | RRF_RT_REG_EXPAND_SZ;
+    let mut kind = 0u32;
+    let mut len = 0u32;
+    // SAFETY: `name` is NUL-terminated and the size query writes only `kind` and `len`.
+    let status =
+        unsafe { RegGetValueW(key, std::ptr::null(), name.as_ptr(), FLAGS, &mut kind, std::ptr::null_mut(), &mut len) };
+    if status != ERROR_SUCCESS || len == 0 {
+        return None;
+    }
+    let buf = loop {
+        let mut buf = vec![0u16; len as usize / 2 + 1];
+        // SAFETY: as above; the buffer holds at least the `len` bytes the call may write.
+        let status = unsafe {
+            RegGetValueW(key, std::ptr::null(), name.as_ptr(), FLAGS, &mut kind, buf.as_mut_ptr() as *mut _, &mut len)
+        };
+        if status == ERROR_SUCCESS {
+            break buf;
+        }
+        if status != ERROR_MORE_DATA || len == 0 {
+            return None;
+        }
+    };
+    let text = String::from_utf16_lossy(&buf);
+    let end = text.find('\0').unwrap_or(text.len());
+    Some(text[..end].to_owned())
+}
+
 /// The user's own `PATH` entries; `None` outside Windows (see the Windows impl).
 #[cfg(not(windows))]
 pub fn user_path() -> Option<OsString> {
@@ -323,6 +512,28 @@ fn append_path_entries(path: &OsStr, extra: &OsStr) -> OsString {
 mod tests {
    use super::*;

+    #[cfg(unix)]
+    #[test]
+    fn kill_tree_of_reaches_what_the_child_started() {
+        use std::io::BufRead;
+        let mut cmd = Command::new("sh");
+        own_group(&mut cmd).args(["-c", "sleep 30 & echo $!; wait"]).stdout(std::process::Stdio::piped());
+        let mut child = cmd.spawn().unwrap();
+        let mut line = String::new();
+        std::io::BufReader::new(child.stdout.take().unwrap()).read_line(&mut line).unwrap();
+        let grandchild: libc::pid_t = line.trim().parse().unwrap();
+        let alive = |pid: libc::pid_t| unsafe { libc::kill(pid, 0) } == 0;
+        assert!(alive(grandchild));
+        kill_tree_of(child.id());
+        let _ = child.wait();
+        // Reparented to init once its parent is gone, which reaps it.
+        let gone = (0..100).any(|_| {
+            std::thread::sleep(Duration::from_millis(20));
+            !alive(grandchild)
+        });
+        assert!(gone, "the grandchild {grandchild} survived");
+    }
+
    #[cfg(windows)]
    #[test]
    fn user_path_reads_the_current_users_path() {
@@ -334,6 +545,96 @@ mod tests {
        }
    }

+    #[cfg(windows)]
+    #[test]
+    fn registry_strings_expand_and_stay_terminator_free() {
+        use windows_sys::Win32::Foundation::ERROR_SUCCESS;
+        use windows_sys::Win32::System::Registry::{
+            HKEY, HKEY_CURRENT_USER, KEY_READ, KEY_WRITE, REG_EXPAND_SZ, REG_SZ, RegCloseKey, RegCreateKeyExW,
+            RegDeleteTreeW, RegSetValueExW,
+        };
+
+        fn wide(s: &str) -> Vec<u16> {
+            s.encode_utf16().chain(std::iter::once(0)).collect()
+        }
+
+        struct TestState {
+            key: HKEY,
+            name: String,
+            variable: String,
+            previous: Option<OsString>,
+        }
+        impl Drop for TestState {
+            fn drop(&mut self) {
+                // SAFETY: the key belongs to this test; Windows environment mutation is safe.
+                unsafe {
+                    RegCloseKey(self.key);
+                    RegDeleteTreeW(HKEY_CURRENT_USER, wide(&self.name).as_ptr());
+                    match &self.previous {
+                        Some(value) => std::env::set_var(&self.variable, value),
+                        None => std::env::remove_var(&self.variable),
+                    }
+                }
+            }
+        }
+        let name = format!("Software\\ai.l0ng.openidea.registry-read-test-{}", std::process::id());
+        let variable = format!("OPENIDEA_TEST_REGVAR_{}", std::process::id());
+        let long = "x".repeat(600);
+        let mut key: HKEY = std::ptr::null_mut();
+        let opened = unsafe {
+            RegCreateKeyExW(
+                HKEY_CURRENT_USER,
+                wide(&name).as_ptr(),
+                0,
+                std::ptr::null(),
+                0,
+                KEY_READ | KEY_WRITE,
+                std::ptr::null(),
+                &mut key,
+                std::ptr::null_mut(),
+            )
+        };
+        assert_eq!(opened, ERROR_SUCCESS, "the test key must be creatable under HKCU\\Software");
+        let _cleanup = TestState { key, name, previous: std::env::var_os(&variable), variable: variable.clone() };
+        // SAFETY: Windows permits environment mutation. No other test uses this process-specific name.
+        unsafe { std::env::set_var(&variable, &long) };
+        let set = |value: &str, kind: u32, data: &[u16]| {
+            // SAFETY: `key` is open for writing and `data` holds `data.len() * 2` bytes.
+            assert_eq!(
+                unsafe {
+                    RegSetValueExW(
+                        key,
+                        wide(value).as_ptr(),
+                        0,
+                        kind,
+                        data.as_ptr() as *const _,
+                        (data.len() * 2) as u32,
+                    )
+                },
+                ERROR_SUCCESS
+            );
+        };
+        let read = |value: &str| read_registry_string(key, &wide(value));
+        set("Plain", REG_SZ, &wide("plain"));
+        set("Expand", REG_EXPAND_SZ, &wide(&format!("%{variable}%\\bin")));
+        set("ExpandLong", REG_EXPAND_SZ, &wide(&format!("%{variable}%")));
+        // Reproduce the reported interior terminator followed by a stale UTF-16 unit.
+        set("TrailingGarbage", REG_SZ, &wide("C:\\Zed\\bin\0n"));
+        set("ExpandTrailingGarbage", REG_EXPAND_SZ, &wide(&format!("%{variable}%\\bin\0n")));
+        set("Empty", REG_SZ, &wide(""));
+        let plain = read("Plain");
+        let expand = read("Expand");
+        let expand_long = read("ExpandLong");
+        assert_eq!(plain.as_deref(), Some("plain"));
+        assert_eq!(expand.as_deref(), Some(format!("{long}\\bin")).as_deref());
+        // Longer than its unexpanded form: needs the re-read at the expanded size.
+        assert_eq!(expand_long.as_deref(), Some(long.as_str()));
+        assert_eq!(read("TrailingGarbage").as_deref(), Some("C:\\Zed\\bin"));
+        assert_eq!(read("ExpandTrailingGarbage").as_deref(), Some(format!("{long}\\bin")).as_deref());
+        assert_eq!(read("Empty").as_deref(), Some(""));
+        assert_eq!(read("Missing"), None);
+    }
+
    #[test]
    fn append_path_entries_keeps_the_order_and_adds_what_is_missing() {
        let join = |dirs: &[&str]| std::env::join_paths(dirs).unwrap();
@@ -363,6 +664,15 @@ mod tests {
        assert_eq!(get("HOME"), Some(None));
        let shell: Vec<_> = shell_env().map(|(k, _)| k).collect();
        assert_eq!(shell, [OsString::from("OPENIDEA_OVERLAY_B")]);
+        // Every child gets what the login shell exports and the IDE process lacks (a Finder
+        // launch: `GOPATH`, `JAVA_HOME`...), unless the call site sets it.
+        assert_eq!(get("OPENIDEA_OVERLAY_B"), Some(Some("b".into())));
+        let mut own = Command::new("true");
+        own.env("OPENIDEA_OVERLAY_B", "call site");
+        host_env(&mut own);
+        let value = own.get_envs().find(|(n, _)| *n == "OPENIDEA_OVERLAY_B").and_then(|(_, v)| v);
+        assert_eq!(value, Some(OsStr::new("call site")));
+        assert_eq!(host_var_os("OPENIDEA_OVERLAY_B"), Some("b".into()));
        assert_eq!(host_var_os("PATH"), Some("/reloaded".into()));
        assert!(host_vars().all(|(k, _)| k != "HOME"));
        assert!(host_vars().any(|(k, v)| k == "OPENIDEA_OVERLAY_A" && v == "project"));
@@ -502,3 +812,71 @@ mod tests {
        assert_eq!(find_executable("nope", &search), None);
    }
 }
+
+#[cfg(all(test, unix))]
+mod kill_tests {
+    use super::*;
+    use std::path::Path;
+    use std::time::Instant;
+
+    /// Runs `script` in `sh` as its own group's leader and waits for it to write `ready`.
+    fn start(script: &str, ready: &Path) -> Child {
+        let mut cmd = Command::new("sh");
+        cmd.arg("-c").arg(script);
+        let child = own_group(&mut cmd).spawn().unwrap();
+        let deadline = Instant::now() + Duration::from_secs(5);
+        while !ready.exists() {
+            assert!(Instant::now() < deadline, "the script never got ready");
+            std::thread::sleep(Duration::from_millis(10));
+        }
+        child
+    }
+
+    fn assert_gone(pid: libc::pid_t) {
+        let deadline = Instant::now() + Duration::from_secs(5);
+        // SAFETY: signal 0 only checks that the process exists.
+        while unsafe { libc::kill(pid, 0) } == 0 {
+            assert!(Instant::now() < deadline, "process {pid} survived");
+            std::thread::sleep(Duration::from_millis(20));
+        }
+    }
+
+    #[test]
+    fn kill_tree_kills_what_the_child_started() {
+        let dir = tempfile::tempdir().unwrap();
+        let pid_file = dir.path().join("pid");
+        let script = format!("sleep 30 & echo $! > '{0}.tmp' && mv '{0}.tmp' '{0}'; wait", pid_file.display());
+        let mut child = start(&script, &pid_file);
+        let grandchild: libc::pid_t = std::fs::read_to_string(&pid_file).unwrap().trim().parse().unwrap();
+        kill_tree(&mut child);
+        assert!(child.try_wait().unwrap().is_some(), "the child is reaped");
+        assert_gone(grandchild);
+    }
+
+    #[test]
+    fn terminate_tree_lets_the_child_clean_up() {
+        let dir = tempfile::tempdir().unwrap();
+        let (ready, cleaned) = (dir.path().join("ready"), dir.path().join("cleaned"));
+        let script = format!(
+            "trap 'touch \"{}\"; exit 0' TERM; touch \"{}\"; sleep 30 & wait",
+            cleaned.display(),
+            ready.display()
+        );
+        let mut child = start(&script, &ready);
+        terminate_tree(&mut child, Duration::from_millis(500));
+        assert!(cleaned.exists(), "the SIGTERM handler ran before the SIGKILL");
+        assert!(child.try_wait().unwrap().is_some(), "the child is reaped");
+    }
+
+    #[test]
+    fn terminate_tree_still_kills_a_child_that_ignores_sigterm() {
+        let dir = tempfile::tempdir().unwrap();
+        let ready = dir.path().join("ready");
+        let script = format!("trap '' TERM; touch \"{}\"; while :; do sleep 1; done", ready.display());
+        let mut child = start(&script, &ready);
+        let started = Instant::now();
+        terminate_tree(&mut child, Duration::from_millis(50));
+        assert!(child.try_wait().unwrap().is_some(), "the child is reaped");
+        assert!(started.elapsed() < Duration::from_secs(5));
+    }
+}
@@ -207,6 +207,58 @@ impl ProxySettings {
        env.push((OsString::from("no_proxy"), Some(OsString::from(no_proxy))));
        env
    }
+
+    /// System properties that make a JVM follow this configuration. A JVM reads none of
+    /// [`Self::child_env`]: a Java tool (jetty, Maven's resolver, a language server's own
+    /// HTTP client) goes direct without these, and a repository its proxy answers in
+    /// milliseconds can then hang it instead.
+    pub fn jvm_args(&self) -> Vec<String> {
+        match self.mode {
+            // macOS and Windows JVMs read the system proxy with this one.
+            ProxyMode::Auto => vec!["-Djava.net.useSystemProxies=true".into()],
+            ProxyMode::None => Vec::new(),
+            ProxyMode::Manual if self.manual() => self.manual_jvm_args(),
+            ProxyMode::Manual => Vec::new(),
+        }
+    }
+
+    fn manual_jvm_args(&self) -> Vec<String> {
+        let (host, port) = (self.host.trim(), self.port);
+        match self.kind {
+            ProxyKind::Http => {
+                // HTTPS hosts read `https.proxyHost`, plain ones `http.proxyHost`.
+                let mut args = vec![
+                    format!("-Dhttp.proxyHost={host}"),
+                    format!("-Dhttp.proxyPort={port}"),
+                    format!("-Dhttps.proxyHost={host}"),
+                    format!("-Dhttps.proxyPort={port}"),
+                ];
+                let hosts = self.non_proxy_hosts();
+                if !hosts.is_empty() {
+                    args.push(format!("-Dhttp.nonProxyHosts={}", hosts.join("|")));
+                }
+                args
+            }
+            // SOCKS proxies every TCP connection, so there is one property pair.
+            ProxyKind::Socks => vec![
+                format!("-DsocksProxyHost={host}"),
+                format!("-DsocksProxyPort={port}"),
+                "-Djava.net.useSystemProxies=false".into(),
+            ],
+        }
+    }
+
+    /// [`Self::no_proxy`] in the JVM's `http.nonProxyHosts` format: `|` between host
+    /// globs. CIDR ranges and IPv6 literals have no equivalent there and are dropped.
+    fn non_proxy_hosts(&self) -> Vec<String> {
+        let mut hosts: Vec<String> = LOOPBACK.iter().filter(|h| !h.contains(':')).map(|h| (*h).to_owned()).collect();
+        for entry in self.no_proxy_entries() {
+            if !entry.contains(['/', ':', '[', ']']) && !hosts.contains(&entry) {
+                hosts.push(entry);
+            }
+        }
+        hosts
+    }
 }

 /// Case-insensitive host glob (`pattern` is lowercase): `*` matches any run of characters.
@@ -292,6 +344,34 @@ mod tests {
        assert!(p.child_env().is_empty());
    }

+    #[test]
+    fn jvm_args_carry_the_proxy_as_system_properties() {
+        // A JVM reads none of `child_env`: a Java language server needs these to not go
+        // direct while curl, git and Node follow the environment.
+        assert_eq!(ProxySettings::default().jvm_args(), ["-Djava.net.useSystemProxies=true"]);
+        assert!(ProxySettings { mode: ProxyMode::None, ..manual("proxy", 3128) }.jvm_args().is_empty());
+        assert_eq!(
+            manual("proxy.corp", 3128).jvm_args(),
+            [
+                "-Dhttp.proxyHost=proxy.corp",
+                "-Dhttp.proxyPort=3128",
+                "-Dhttps.proxyHost=proxy.corp",
+                "-Dhttps.proxyPort=3128",
+                "-Dhttp.nonProxyHosts=localhost|127.0.0.1",
+            ]
+        );
+        let socks = ProxySettings { kind: ProxyKind::Socks, ..manual("10.0.0.1", 1080) };
+        assert_eq!(socks.jvm_args()[..2], ["-DsocksProxyHost=10.0.0.1", "-DsocksProxyPort=1080"]);
+        // `http.nonProxyHosts` takes host globs: CIDR ranges and IPv6 literals drop out.
+        let p = ProxySettings {
+            no_proxy: "*.corp.com, 172.0.0.0/8, [::1], ::1, localhost".into(),
+            ..manual("proxy.corp", 3128)
+        };
+        assert_eq!(p.jvm_args().last().unwrap(), "-Dhttp.nonProxyHosts=localhost|127.0.0.1|*.corp.com");
+        // A manual proxy without a host connects directly, and so does its JVM.
+        assert!(manual(" ", 80).jvm_args().is_empty());
+    }
+
    #[test]
    fn manual_http_and_socks_urls() {
        let p = manual("proxy.corp", 3128);
@@ -132,7 +132,7 @@ pub struct DeploymentServer {
 #[derive(Clone, Debug, Default, PartialEq, Eq, Serialize, Deserialize, Type)]
 #[serde(default, rename_all = "camelCase")]
 pub struct DeploymentMapping {
-    /// Project-relative folder; empty = the project root.
+    /// Project-relative folder, or absolute inside the project; empty = the project root.
    pub local: String,
    /// Remote folder, relative to the server root (a leading `/` is the root too).
    pub deployment: String,
@@ -58,6 +58,68 @@ pub struct Settings {
    pub deployment: DeploymentSettings,
    /// Build, Execution, Deployment › Run Targets.
    pub run_targets: Vec<RunTarget>,
+    pub cmake: CMakeSettings,
+    /// Tools › Agents › Chat.
+    pub agents: AgentSettings,
+    /// Plugin settings (`[contributes.settings]`): plugin id → its values by key.
+    #[specta(type = BTreeMap<String, BTreeMap<String, specta_typescript::Unknown>>)]
+    pub plugins: BTreeMap<String, serde_json::Map<String, serde_json::Value>>,
+}
+
+/// What the meters in an agent task's header show.
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize, Type)]
+#[serde(default, rename_all = "camelCase")]
+pub struct AgentSettings {
+    /// Context window use.
+    pub show_context_usage: bool,
+    /// Time the agent spent on the task.
+    pub show_work_time: bool,
+    /// The account's usage-limit windows (Claude's 5-hour and weekly limits).
+    pub show_usage_limits: bool,
+    /// What the session has cost so far, as the agent reports it.
+    pub show_cost: bool,
+}
+
+impl Default for AgentSettings {
+    fn default() -> Self {
+        Self { show_context_usage: true, show_work_time: true, show_usage_limits: true, show_cost: false }
+    }
+}
+
+/// Absent profiles retain automatic discovery for existing projects.
+#[derive(Clone, Debug, Default, PartialEq, Serialize, Deserialize, Type)]
+#[serde(default, rename_all = "camelCase")]
+pub struct CMakeSettings {
+    #[serde(skip_serializing_if = "Option::is_none")]
+    #[specta(optional)]
+    pub profiles: Option<Vec<CMakeProfile>>,
+}
+
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize, Type)]
+#[serde(default, rename_all = "camelCase")]
+pub struct CMakeProfile {
+    pub name: String,
+    pub build_type: String,
+    pub generator: String,
+    pub cmake_args: Vec<String>,
+    /// Empty uses cmake-build-<lowercase build type>.
+    pub build_dir: String,
+    pub build_args: Vec<String>,
+    pub env: BTreeMap<String, String>,
+}
+
+impl Default for CMakeProfile {
+    fn default() -> Self {
+        Self {
+            name: "Debug".into(),
+            build_type: "Debug".into(),
+            generator: String::new(),
+            cmake_args: Vec::new(),
+            build_dir: String::new(),
+            build_args: Vec::new(),
+            env: BTreeMap::new(),
+        }
+    }
 }

 #[derive(Clone, Debug, Default, PartialEq, Eq, Serialize, Deserialize, Type)]
@@ -95,6 +157,16 @@ pub struct LanguageServerSettings {
    pub languages: Vec<String>,
    /// Files marking a workspace root for a server defined here (`pyproject.toml`).
    pub root_markers: Vec<String>,
+    /// Replaces the definition's `features`: what the server is used for
+    /// (`code-action`, `hover`, …); an empty list means everything.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    #[specta(optional)]
+    pub features: Option<Vec<String>>,
+    /// Replaces the definition's `code-action-kinds` (`refactor`); an empty
+    /// list keeps every kind.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    #[specta(optional)]
+    pub code_action_kinds: Option<Vec<String>>,
 }

 impl Default for LanguageServerSettings {
@@ -108,6 +180,8 @@ impl Default for LanguageServerSettings {
            settings: None,
            languages: Vec::new(),
            root_markers: Vec::new(),
+            features: None,
+            code_action_kinds: None,
        }
    }
 }
@@ -154,6 +228,9 @@ impl Default for Settings {
            ssh: SshSettings::default(),
            deployment: DeploymentSettings::default(),
            run_targets: Vec::new(),
+            cmake: CMakeSettings::default(),
+            agents: AgentSettings::default(),
+            plugins: BTreeMap::new(),
        }
    }
 }
@@ -197,7 +274,7 @@ impl Default for GeneralSettings {
    fn default() -> Self {
        Self {
            reopen_last_project: true,
-            confirm_exit: false,
+            confirm_exit: true,
            open_project_in: "ask".into(),
            default_project_directory: String::new(),
            save_on_idle: false,
@@ -262,7 +339,8 @@ impl Default for NotificationGroupSettings {
 #[derive(Clone, Debug, PartialEq, Serialize, Deserialize, Type)]
 #[serde(default, rename_all = "camelCase")]
 pub struct AppearanceSettings {
-    /// `dark` | `light` | `system` | `dark-hc` (high-contrast dark)
+    /// A built-in theme id (`light`, `dark`, `dark-hc`, …), `system` (legacy
+    /// "Sync with OS"), or a plugin's theme: `plugin:<plugin-id>/<theme-id>`.
    pub theme: String,
    pub accent: String,
    pub ui_font_size: f32,
@@ -271,6 +349,9 @@ pub struct AppearanceSettings {
    pub sync_with_os: bool,
    pub preferred_light_theme: String,
    pub preferred_dark_theme: String,
+    /// A plugin's file icon theme (`<plugin-id>/<theme-id>`); empty = the built-in icons.
+    pub file_icon_theme: String,
+    pub file_icon_theme_options: BTreeMap<String, FileIconThemeOptions>,
    /// IDE zoom in percent (50–300).
    pub zoom: u32,
    /// Apply `ui_font_family` / `ui_font_size` (otherwise the theme's).
@@ -306,6 +387,24 @@ pub struct AppearanceSettings {
 /// Main toolbar entries per side, in order: title widget ids (`project`,
 /// `vcs.branch`…) or `action:<id>`. Widgets in neither list nor `hidden`
 /// (registered later) keep their default place.
+#[derive(Clone, Debug, Default, PartialEq, Eq, Serialize, Deserialize, Type)]
+#[serde(default, rename_all = "camelCase")]
+pub struct FileIconThemeOptions {
+    pub groups: BTreeMap<String, bool>,
+    pub choices: BTreeMap<String, String>,
+    pub hide_files: bool,
+    pub hide_folders: bool,
+    pub hollow_folders: bool,
+    pub hide_ui_icons: bool,
+    pub hide_psi_icons: bool,
+    pub monochrome: Option<String>,
+    pub saturation: Option<u8>,
+    pub opacity: Option<u8>,
+    pub icon_size: Option<u8>,
+    pub row_height: Option<u8>,
+    pub accent: Option<String>,
+}
+
 #[derive(Clone, Debug, Default, PartialEq, Eq, Serialize, Deserialize, Type)]
 #[serde(default, rename_all = "camelCase")]
 pub struct MainToolbarSettings {
@@ -325,6 +424,8 @@ impl Default for AppearanceSettings {
            sync_with_os: false,
            preferred_light_theme: "light".into(),
            preferred_dark_theme: "dark".into(),
+            file_icon_theme: String::new(),
+            file_icon_theme_options: BTreeMap::new(),
            zoom: 100,
            use_custom_font: false,
            ui_font_family: "Inter".into(),
@@ -500,33 +601,102 @@ impl Default for FileSettings {
    }
 }

-#[derive(Clone, Debug, Default, PartialEq, Serialize, Deserialize, Type)]
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize, Type)]
 #[serde(default, rename_all = "camelCase")]
 pub struct LanguagesSettings {
    pub python: PythonSettings,
    pub node: NodeSettings,
+    pub php: PhpSettings,
    pub rust: RustSettings,
    pub go: GoSettings,
    pub typescript: TypeScriptSettings,
-    pub prettier: PrettierSettings,
+    pub prettier: ExternalFormatterSettings,
+    pub oxfmt: ExternalFormatterSettings,
+    pub ruff: ExternalFormatterSettings,
    pub java: JavaSettings,
+    pub ruby: RubySettings,
+    pub markdown: MarkdownSettings,
 }

+impl Default for LanguagesSettings {
+    fn default() -> Self {
+        Self {
+            python: PythonSettings::default(),
+            node: NodeSettings::default(),
+            php: PhpSettings::default(),
+            rust: RustSettings::default(),
+            go: GoSettings::default(),
+            typescript: TypeScriptSettings::default(),
+            prettier: ExternalFormatterSettings::default(),
+            oxfmt: ExternalFormatterSettings::default(),
+            ruff: ExternalFormatterSettings {
+                languages: vec!["python".into()],
+                ..ExternalFormatterSettings::default()
+            },
+            java: JavaSettings::default(),
+            ruby: RubySettings::default(),
+            markdown: MarkdownSettings::default(),
+        }
+    }
+}
+
+/// Languages & Frameworks › Markdown. Like IDEA's, it is application-level only.
+#[derive(Clone, Debug, Default, PartialEq, Serialize, Deserialize, Type)]
+#[serde(default, rename_all = "camelCase")]
+pub struct MarkdownSettings {
+    /// Preview (and notebook Markdown cell) font size in px; unset follows the editor font size.
+    pub preview_font_size: Option<u32>,
+}
+
+impl LanguagesSettings {
+    pub fn formatter(&self, tool: ExternalFormatter) -> &ExternalFormatterSettings {
+        match tool {
+            ExternalFormatter::Prettier => &self.prettier,
+            ExternalFormatter::Oxfmt => &self.oxfmt,
+            ExternalFormatter::Ruff => &self.ruff,
+        }
+    }
+}
+
+/// A formatter that runs outside the language servers, with its own settings group.
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Serialize, Deserialize, Type)]
+#[serde(rename_all = "lowercase")]
+pub enum ExternalFormatter {
+    Prettier,
+    Oxfmt,
+    Ruff,
+}
+
+impl ExternalFormatter {
+    /// The name of the tool in the tool registry.
+    pub fn name(self) -> &'static str {
+        match self {
+            Self::Prettier => "prettier",
+            Self::Oxfmt => "oxfmt",
+            Self::Ruff => "ruff",
+        }
+    }
+}
+
+/// An external formatter (Prettier, oxfmt, Ruff) and the languages it formats.
 #[derive(Clone, Debug, PartialEq, Serialize, Deserialize, Type)]
 #[serde(default, rename_all = "camelCase")]
-pub struct PrettierSettings {
-    /// Empty path: project node_modules, managed installation, then PATH.
+pub struct ExternalFormatterSettings {
+    /// Empty path: project node_modules (Prettier/oxfmt), managed installation, then PATH.
    pub path: String,
+    /// Ruff only: directory containing its configuration, or a configuration file.
+    pub configuration_directory: String,
    pub languages: Vec<String>,
-    /// Prefer Prettier even when a language server offers formatting.
+    /// Prefer this formatter even when a language server offers formatting.
    pub prefer: bool,
    pub run_on_save: bool,
 }

-impl Default for PrettierSettings {
+impl Default for ExternalFormatterSettings {
    fn default() -> Self {
        Self {
            path: String::new(),
+            configuration_directory: String::new(),
            languages: [
                "markdown",
                "yaml",
@@ -567,6 +737,33 @@ impl Default for PythonSettings {
    }
 }

+#[derive(Clone, Debug, Default, PartialEq, Serialize, Deserialize, Type)]
+#[serde(default, rename_all = "camelCase")]
+pub struct PhpSettings {
+    /// `php` CLI executable; empty = the one on `PATH`.
+    pub interpreter: String,
+    /// PHP version the language server checks the code against (`7.4`); empty = from
+    /// `composer.json` (`config.platform.php`, else the lowest version `require.php` allows).
+    pub language_level: String,
+    /// Folders outside the project whose code the language server indexes too (a platform a
+    /// module extends); absolute, `~/`, or relative to the project.
+    pub include_paths: Vec<String>,
+    /// Intelephense stub sets loaded on top of its defaults and the `ext-*` entries of
+    /// `composer.json` (`wordpress`).
+    pub stubs: Vec<String>,
+    /// PHPStan configuration file for checking saved files; empty = the `phpstan.neon`,
+    /// `phpstan.neon.dist` or `phpstan.dist.neon` PHPStan finds in the project root. Absolute,
+    /// `~/`, or relative to the project.
+    pub phpstan_config: String,
+}
+
+#[derive(Clone, Debug, Default, PartialEq, Serialize, Deserialize, Type)]
+#[serde(default, rename_all = "camelCase")]
+pub struct RubySettings {
+    /// Project interpreter executable; empty = auto-detect (`.ruby-version`, mise / asdf, else `ruby` on PATH).
+    pub interpreter: String,
+}
+
 #[derive(Clone, Debug, Default, PartialEq, Serialize, Deserialize, Type)]
 #[serde(default, rename_all = "camelCase")]
 pub struct NodeSettings {
@@ -664,6 +861,8 @@ pub struct JavaSettings {
 #[derive(Clone, Debug, Default, PartialEq, Serialize, Deserialize, Type)]
 #[serde(default, rename_all = "camelCase")]
 pub struct GradleSettings {
+    /// Linked build directories; absent preserves automatic discovery, empty unlinks all builds.
+    pub linked_projects: Option<Vec<String>>,
    /// Empty = Project JDK; otherwise a JDK home.
    pub jvm: String,
    pub distribution: GradleDistribution,
@@ -671,6 +870,19 @@ pub struct GradleSettings {
    pub home: String,
    /// Empty = Gradle's default user home.
    pub user_home: String,
+    /// IDEA's "Build and run using": who builds and launches an Application main.
+    pub run_using: GradleRunUsing,
+}
+
+/// IDEA's "Build and run using" for Gradle builds; IDEA defaults to Gradle.
+#[derive(Clone, Debug, Default, PartialEq, Serialize, Deserialize, Type)]
+#[serde(rename_all = "camelCase")]
+pub enum GradleRunUsing {
+    /// A `JavaExec` task on the source set's runtime classpath (`gradleRun.gradle`).
+    #[default]
+    Gradle,
+    /// The Java language server's classpath, launched by OpenIDEA.
+    Ide,
 }

 #[derive(Clone, Debug, Default, PartialEq, Serialize, Deserialize, Type)]
@@ -687,12 +899,20 @@ pub enum GradleDistribution {
 pub struct MavenSettings {
    /// Project-relative root POMs removed from the Maven project model.
    pub unlinked_projects: Vec<String>,
+    /// Project-relative POMs outside the root reactor added as independent top-level projects.
+    pub linked_projects: Vec<String>,
    /// Maven home (or its `mvn` executable); empty = the project's `mvnw`, else `mvn` on `PATH`.
    pub home: String,
    /// User `settings.xml` (`-s`); empty = `~/.m2/settings.xml`.
    pub user_settings: String,
    /// Local repository (`-Dmaven.repo.local`); empty = from `settings.xml`.
    pub local_repository: String,
+    /// Run Maven through the Maven Daemon (`mvnd`) for faster builds. mvnd embeds
+    /// its own Maven, so `home` and the project's `mvnw` are bypassed when it is on.
+    pub daemon: bool,
+    /// Maven Daemon home (or its `mvnd` executable); empty = `$MVND_HOME`, else
+    /// `mvnd` on `PATH` / common install dirs. Only used when `daemon` is on.
+    pub mvnd_home: String,
 }

 #[derive(Clone, Debug, PartialEq, Serialize, Deserialize, Type)]
@@ -765,6 +985,54 @@ impl Settings {
 mod tests {
    use super::*;

+    #[test]
+    fn cmake_profile_argument_arrays_round_trip() {
+        let mut settings = Settings::default();
+        assert!(settings.cmake.profiles.is_none());
+        assert!(CMakeProfile::default().cmake_args.is_empty());
+        assert!(CMakeProfile::default().build_args.is_empty());
+        let profile = CMakeProfile {
+            cmake_args: ["-DMESSAGE=two words", "-DQUOTE=\"hello\"", ""].map(String::from).into(),
+            build_args: ["-j", "8", "--", "LABEL=it's a build"].map(String::from).into(),
+            ..Default::default()
+        };
+        settings.cmake.profiles = Some(vec![profile.clone()]);
+        let value = serde_json::to_value(&settings).unwrap();
+        assert_eq!(value["cmake"]["profiles"][0]["cmakeArgs"], serde_json::json!(profile.cmake_args));
+        assert_eq!(value["cmake"]["profiles"][0]["buildArgs"], serde_json::json!(profile.build_args));
+        assert_eq!(serde_json::from_value::<Settings>(value).unwrap(), settings);
+    }
+
+    #[test]
+    fn file_icon_theme_options_default_empty_and_round_trip() {
+        let old: Settings = serde_json::from_str(r#"{"appearance":{"fileIconTheme":"p/t"}}"#).unwrap();
+        assert!(old.appearance.file_icon_theme_options.is_empty());
+        let json = serde_json::json!({"appearance":{"fileIconThemeOptions":{"p/t":{
+            "groups":{"tests":true},"choices":{"arrows":"plusminus"},"hideFiles":true,"hideFolders":false,"hollowFolders":true,"hideUiIcons":true,"hidePsiIcons":false,
+            "monochrome":"#546e7a","saturation":5,"opacity":80,"iconSize":20,"rowHeight":30,"accent":"#009688"}}}});
+        let settings: Settings = serde_json::from_value(json.clone()).unwrap();
+        let options = &settings.appearance.file_icon_theme_options["p/t"];
+        assert!(options.hide_files && options.hollow_folders && !options.hide_folders);
+        assert!(options.hide_ui_icons && !options.hide_psi_icons);
+        assert!(options.groups["tests"]);
+        assert_eq!(options.choices["arrows"], "plusminus");
+        assert_eq!(
+            (options.saturation, options.opacity, options.icon_size, options.row_height),
+            (Some(5), Some(80), Some(20), Some(30))
+        );
+        assert_eq!(options.monochrome.as_deref(), Some("#546e7a"));
+        assert_eq!(options.accent.as_deref(), Some("#009688"));
+        let value = serde_json::to_value(&settings).unwrap();
+        let restored: Settings = serde_json::from_value(value).unwrap();
+        assert_eq!(restored, settings);
+        let plain = serde_json::to_value(FileIconThemeOptions::default()).unwrap();
+        assert_eq!(plain["hideFiles"], false);
+        assert_eq!(plain["hideUiIcons"], false);
+        assert_eq!(plain["hidePsiIcons"], false);
+        assert_eq!(plain["monochrome"], serde_json::Value::Null);
+        assert_eq!(plain["groups"], serde_json::json!({}));
+    }
+
    #[test]
    fn ui_font_fallback_defaults_empty_and_round_trips() {
        let old: Settings = serde_json::from_str(r#"{"appearance":{"useCustomFont":true}}"#).unwrap();
@@ -794,6 +1062,20 @@ mod tests {
        }
    }

+    #[test]
+    fn agent_meters_default_and_round_trip() {
+        let old: Settings = serde_json::from_str(r#"{"agents":{"showCost":true}}"#).unwrap();
+        assert!(old.agents.show_cost);
+        assert!(old.agents.show_context_usage && old.agents.show_work_time && old.agents.show_usage_limits);
+        assert!(!Settings::default().agents.show_cost);
+        let mut settings = Settings::default();
+        settings.agents.show_usage_limits = false;
+        let json = serde_json::to_value(&settings).unwrap();
+        assert_eq!(json["agents"]["showUsageLimits"], false);
+        let restored: Settings = serde_json::from_value(json).unwrap();
+        assert_eq!(restored.agents, settings.agents);
+    }
+
    #[test]
    fn main_menu_style_defaults_and_round_trips() {
        let old: Settings = serde_json::from_str(r#"{"appearance":{"compactMode":true}}"#).unwrap();
@@ -862,12 +1144,33 @@ mod maven_linkage_tests {
        assert!(encoded.contains("unlinkedProjects"));
        assert_eq!(serde_json::from_str::<MavenSettings>(&encoded).unwrap(), settings);
    }
+
+    #[test]
+    fn daemon_settings_round_trip() {
+        // Old settings files predate the daemon fields; `serde(default)` keeps them loadable.
+        let old: MavenSettings = serde_json::from_str(r#"{"home":"/opt/maven"}"#).unwrap();
+        assert!(!old.daemon && old.mvnd_home.is_empty());
+        let settings = MavenSettings { daemon: true, mvnd_home: "/opt/mvnd".into(), ..old };
+        let encoded = serde_json::to_string(&settings).unwrap();
+        assert!(encoded.contains("\"daemon\":true") && encoded.contains("mvndHome"));
+        assert_eq!(serde_json::from_str::<MavenSettings>(&encoded).unwrap(), settings);
+    }
 }

 #[cfg(test)]
 mod gradle_settings_tests {
    use super::*;

+    #[test]
+    fn absent_and_explicitly_empty_gradle_links_remain_distinct() {
+        let automatic: GradleSettings = serde_json::from_str("{}").unwrap();
+        let unlinked: GradleSettings = serde_json::from_str(r#"{"linkedProjects":[]}"#).unwrap();
+        assert_eq!(automatic.linked_projects, None);
+        assert_eq!(unlinked.linked_projects, Some(vec![]));
+        let restored: GradleSettings = serde_json::from_str(&serde_json::to_string(&unlinked).unwrap()).unwrap();
+        assert_eq!(restored.linked_projects, Some(vec![]));
+    }
+
    #[test]
    fn defaults_and_round_trip() {
        let old: JavaSettings = serde_json::from_str(r#"{"jdk":"/jdk"}"#).unwrap();
@@ -879,6 +1182,8 @@ mod gradle_settings_tests {
                distribution,
                home: "/gradle".into(),
                user_home: "/cache/gradle".into(),
+                run_using: GradleRunUsing::Ide,
+                linked_projects: Some(vec!["backend".into(), "../shared".into()]),
            };
            let restored: Settings = serde_json::from_str(&serde_json::to_string(&settings).unwrap()).unwrap();
            assert_eq!(restored.languages.java.gradle, settings.languages.java.gradle);
@@ -44,6 +44,39 @@ pub fn cancel(id: TaskId) -> bool {
    }
 }

+/// A progress title a tool reported, made readable: a leading absolute executable path
+/// (rust-analyzer reports `/…/bin/cargo check`) shows as its program name (`cargo check`).
+pub fn display_title(title: &str) -> String {
+    let is_sep = |c: char| c == '/' || c == '\\';
+    let b = title.as_bytes();
+    let absolute = title.starts_with(is_sep)
+        || (b.len() > 2 && b[0].is_ascii_alphabetic() && b[1] == b':' && is_sep(b[2] as char));
+    if !absolute {
+        return title.to_owned();
+    }
+    // The path runs on through spaces (`Application Support/…`) while the next word still
+    // continues it; the first word without a separator, an option or a new path ends it.
+    let mut end = title.find(' ').unwrap_or(title.len());
+    while end < title.len() {
+        let rest = &title[end + 1..];
+        let word = rest.split(' ').next().unwrap_or_default();
+        if word.is_empty() || !word.contains(is_sep) || word.starts_with(is_sep) || word.starts_with('-') {
+            break;
+        }
+        end += 1 + word.len();
+    }
+    let (path, rest) = title.split_at(end);
+    let name = path.rsplit(is_sep).next().unwrap_or(path);
+    let name = [".exe", ".cmd", ".bat"]
+        .iter()
+        .find_map(|ext| {
+            let cut = name.len().checked_sub(ext.len())?;
+            (name.is_char_boundary(cut) && name[cut..].eq_ignore_ascii_case(ext)).then(|| &name[..cut])
+        })
+        .unwrap_or(name);
+    if name.is_empty() { title.to_owned() } else { format!("{name}{rest}") }
+}
+
 #[cfg(test)]
 mod tests {
    use super::*;
@@ -71,4 +104,28 @@ mod tests {
        assert!(!cancel(other), "an ended task is not cancelled");
        assert_eq!(hits.load(Ordering::SeqCst), 1);
    }
+
+    #[test]
+    fn display_title_shows_a_leading_executable_path_as_its_name() {
+        for (title, shown) in [
+            ("/Users/thomas/Library/Application Support/mbx/bin/cargo check", "cargo check"),
+            ("/home/me/.cargo/bin/cargo clippy (#2)", "cargo clippy (#2)"),
+            (
+                "/opt/my tools/bin/cargo check --manifest-path /x/Cargo.toml",
+                "cargo check --manifest-path /x/Cargo.toml",
+            ),
+            (r"C:\Users\me\.cargo\bin\cargo.exe check", "cargo check"),
+            (r"C:\Program Files\Rust\bin\cargo.EXE check", "cargo check"),
+            (r"\\server\share\tools\x.cmd build", "x build"),
+            ("/usr/bin/make", "make"),
+            ("cargo check", "cargo check"),
+            ("Indexing", "Indexing"),
+            ("Building compile-time-deps", "Building compile-time-deps"),
+            ("Loading /src/app (2/3)", "Loading /src/app (2/3)"),
+            ("/", "/"),
+            ("", ""),
+        ] {
+            assert_eq!(display_title(title), shown, "{title:?}");
+        }
+    }
 }
@@ -97,6 +97,16 @@ pub struct TextEdit {
 #[derive(Clone, Debug, Default, PartialEq, Eq, Serialize, Deserialize, Type)]
 pub struct WorkspaceEdit {
    pub files: Vec<FileEdit>,
+    /// Content fingerprints captured before presenting an edit for confirmation.
+    #[serde(default)]
+    #[specta(optional)]
+    pub preconditions: Vec<WorkspaceEditPrecondition>,
+}
+
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize, Type)]
+pub struct WorkspaceEditPrecondition {
+    pub path: crate::IpcPath,
+    pub hash: String,
 }

 impl WorkspaceEdit {
@@ -108,17 +118,26 @@ impl WorkspaceEdit {
        let mut resolve_aliases = true;
        for file in std::mem::take(&mut self.files) {
            match file {
-                FileEdit::Edit { path, edits } => {
+                FileEdit::Edit { path, edits, version } => {
                    let path = if resolve_aliases {
                        dunce::canonicalize(&path).unwrap_or_else(|_| path.to_path_buf())
                    } else {
                        path.to_path_buf()
                    };
                    let index = *batch.entry(path.clone()).or_insert_with(|| {
-                        files.push(FileEdit::Edit { path: path.into(), edits: Vec::new() });
+                        files.push(FileEdit::Edit { path: path.clone().into(), edits: Vec::new(), version });
                        files.len() - 1
                    });
-                    let FileEdit::Edit { edits: own, .. } = &mut files[index] else { unreachable!() };
+                    let FileEdit::Edit { edits: own, version: expected, .. } = &mut files[index] else {
+                        unreachable!()
+                    };
+                    if expected.is_some() && version.is_some() && *expected != version {
+                        // Keep incompatible constraints so application rejects them
+                        // before changing any file instead of silently losing one.
+                        files.push(FileEdit::Edit { path: path.into(), edits, version });
+                        continue;
+                    }
+                    *expected = expected.or(version);
                    for edit in edits {
                        if !own.contains(&edit) {
                            own.push(edit);
@@ -140,10 +159,26 @@ impl WorkspaceEdit {
 #[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize, Type)]
 #[serde(tag = "kind", rename_all = "camelCase")]
 pub enum FileEdit {
-    Edit { path: crate::IpcPath, edits: Vec<TextEdit> },
-    Create { path: crate::IpcPath, overwrite: bool },
-    Rename { from: crate::IpcPath, to: crate::IpcPath },
-    Delete { path: crate::IpcPath, recursive: bool },
+    Edit {
+        path: crate::IpcPath,
+        edits: Vec<TextEdit>,
+        /// LSP TextDocumentEdit version; null/unversioned edits use content preconditions.
+        #[serde(default)]
+        #[specta(optional)]
+        version: Option<i32>,
+    },
+    Create {
+        path: crate::IpcPath,
+        overwrite: bool,
+    },
+    Rename {
+        from: crate::IpcPath,
+        to: crate::IpcPath,
+    },
+    Delete {
+        path: crate::IpcPath,
+        recursive: bool,
+    },
 }

 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, Serialize, Deserialize, Type)]
@@ -254,7 +289,7 @@ mod workspace_edit_tests {
        std::fs::write(&real, "add()").unwrap();
        std::os::unix::fs::symlink(&real, &alias).unwrap();
        let change = TextEdit { range: Range::new(Pos::new(0, 0), Pos::new(0, 3)), new_text: "sum_values".into() };
-        let edit = |path: PathBuf| FileEdit::Edit { path: path.into(), edits: vec![change.clone()] };
+        let edit = |path: PathBuf| FileEdit::Edit { path: path.into(), edits: vec![change.clone()], version: None };
        let mut workspace = WorkspaceEdit {
            files: vec![
                edit(real.clone()),
@@ -262,6 +297,7 @@ mod workspace_edit_tests {
                FileEdit::Create { path: dir.path().join("other").into(), overwrite: false },
                edit(real),
            ],
+            ..Default::default()
        };
        workspace.deduplicate();
        assert_eq!(workspace.files.len(), 3);
@@ -30,6 +30,21 @@ pub fn search_path() -> OsString {
    std::env::join_paths(dirs).unwrap_or_default()
 }

+/// Ruby code printing where `gem install` puts executables: the Ruby's own `Gem.bindir`, which
+/// Homebrew's Ruby keeps off `PATH`, and the `--user-install` one.
+pub const RUBY_GEM_BIN_SCRIPT: &str = "puts Gem.bindir, File.join(Gem.user_dir, 'bin')";
+
+/// The directories [`RUBY_GEM_BIN_SCRIPT`] printed that exist.
+pub fn gem_bin_dirs(output: &str) -> Vec<PathBuf> {
+    let mut dirs: Vec<PathBuf> = Vec::new();
+    for dir in output.lines().map(str::trim).map(PathBuf::from) {
+        if dir.is_absolute() && dir.is_dir() && !dirs.contains(&dir) {
+            dirs.push(dir);
+        }
+    }
+    dirs
+}
+
 /// Resolves a command on the shared path, or an explicit path relative to `root`.
 pub fn find_command(command: &str, search: &OsStr, root: &Path) -> Option<PathBuf> {
    let path = Path::new(command);
@@ -18,6 +18,7 @@ pub enum Tool {
    Go,
    Maven,
    Gradle,
+    Ruby,
 }

 impl Tool {
@@ -30,6 +31,7 @@ impl Tool {
            Tool::Go => &["go", "golang"],
            Tool::Maven => &["maven"],
            Tool::Gradle => &["gradle"],
+            Tool::Ruby => &["ruby"],
        }
    }
 }
@@ -41,6 +41,8 @@ impl Default for VcsSettings {
 #[derive(Clone, Debug, PartialEq, Serialize, Deserialize, Type)]
 #[serde(default, rename_all = "camelCase")]
 pub struct GitSettings {
+    /// Show blame after the current editor line.
+    pub inline_blame: bool,
    /// Path to the git executable; empty = auto-detect.
    pub executable: String,
    /// Default of Update Project: `merge` | `rebase`.
@@ -71,6 +73,7 @@ pub struct GitSettings {
 impl Default for GitSettings {
    fn default() -> Self {
        Self {
+            inline_blame: false,
            executable: String::new(),
            update_method: "merge".into(),
            auto_update_on_push_rejected: false,
@@ -0,0 +1,137 @@
+//! Projects that live inside a WSL distro are reached from Windows through the
+//! `\\wsl.localhost\<distro>` (or legacy `\\wsl$\<distro>`) share.
+
+use std::path::Path;
+
+/// The WSL launcher on Windows.
+pub const EXE: &str = "wsl.exe";
+
+/// A location inside a WSL distro.
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct WslPath {
+    pub distro: String,
+    /// Absolute Linux path, e.g. `/home/me/app`.
+    pub path: String,
+}
+
+/// Splits a WSL share path into distro and Linux path. Pure string work, so it
+/// accepts every spelling the UI and the OS produce: `\\wsl.localhost\X\a`,
+/// `//wsl$/X/a` and the verbatim `\\?\UNC\wsl.localhost\X\a`.
+pub fn parse(path: &Path) -> Option<WslPath> {
+    let s = path.to_string_lossy().replace('\\', "/");
+    let s = match s.strip_prefix("//?/UNC/") {
+        Some(rest) => format!("//{rest}"),
+        None => s,
+    };
+    let rest = s.strip_prefix("//")?;
+    let (host, rest) = rest.split_once('/')?;
+    if !host.eq_ignore_ascii_case("wsl.localhost") && !host.eq_ignore_ascii_case("wsl$") {
+        return None;
+    }
+    let (distro, tail) = rest.split_once('/').unwrap_or((rest, ""));
+    if distro.is_empty() {
+        return None;
+    }
+    Some(WslPath { distro: distro.to_owned(), path: format!("/{}", tail.trim_end_matches('/')) })
+}
+
+/// A distro name `wsl.exe -d` can be given safely: Windows creates them from letters, digits,
+/// `.`, `_` and `-`. A leading `-` would be read as an option, so it is refused too.
+pub fn is_valid_distro(name: &str) -> bool {
+    !name.is_empty()
+        && name.len() <= 64
+        && !name.starts_with('-')
+        && name.chars().all(|c| c.is_ascii_alphanumeric() || matches!(c, '.' | '_' | '-'))
+}
+
+/// Text of `wsl.exe`'s own output: UTF-16LE (with or without BOM) for its management commands
+/// and its error messages, UTF-8 for what a command inside the distro prints.
+pub fn decode_output(raw: &[u8]) -> String {
+    if raw.starts_with(&[0xff, 0xfe]) || raw.get(1) == Some(&0) {
+        let units: Vec<u16> = raw.as_chunks::<2>().0.iter().map(|c| u16::from_le_bytes(*c)).collect();
+        String::from_utf16_lossy(&units)
+    } else {
+        String::from_utf8_lossy(raw).into_owned()
+    }
+}
+
+/// Distro names from the output of `wsl.exe -l -q`. That output is UTF-16LE (UTF-8 when
+/// `WSL_UTF8=1`), one name per line; names that fail [`is_valid_distro`] are dropped, which also
+/// removes the localized "no installed distributions" message `wsl.exe` prints when there are none.
+pub fn parse_distro_list(raw: &[u8]) -> Vec<String> {
+    let text = decode_output(raw);
+    let mut names: Vec<String> = Vec::new();
+    for line in text.lines() {
+        let name = line.trim_matches(|c: char| c.is_whitespace() || c == '\u{feff}');
+        if is_valid_distro(name) && !names.iter().any(|n| n == name) {
+            names.push(name.to_owned());
+        }
+    }
+    names
+}
+
+/// Installed WSL distros. Empty off Windows, when WSL is not installed or when `wsl.exe` fails.
+pub fn list_distros() -> Vec<String> {
+    #[cfg(windows)]
+    {
+        let mut cmd = std::process::Command::new(EXE);
+        cmd.args(["-l", "-q"]);
+        crate::process::prepare(&mut cmd);
+        match cmd.output() {
+            Ok(out) if out.status.success() => parse_distro_list(&out.stdout),
+            _ => Vec::new(),
+        }
+    }
+    #[cfg(not(windows))]
+    Vec::new()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn p(s: &str) -> Option<(String, String)> {
+        parse(Path::new(s)).map(|w| (w.distro, w.path))
+    }
+
+    #[test]
+    fn every_spelling_of_the_share_is_recognised() {
+        let want = Some(("Ubuntu-24.04".to_owned(), "/home/me/app".to_owned()));
+        assert_eq!(p(r"\\wsl.localhost\Ubuntu-24.04\home\me\app"), want);
+        assert_eq!(p("//wsl.localhost/Ubuntu-24.04/home/me/app"), want);
+        assert_eq!(p(r"\\wsl$\Ubuntu-24.04\home\me\app\"), want);
+        assert_eq!(p(r"\\?\UNC\WSL.LOCALHOST\Ubuntu-24.04\home\me\app"), want);
+    }
+
+    #[test]
+    fn distro_root_and_foreign_paths() {
+        assert_eq!(p(r"\\wsl.localhost\Debian"), Some(("Debian".to_owned(), "/".to_owned())));
+        assert_eq!(p(r"\\server\share\a"), None);
+        assert_eq!(p(r"\\wsl.localhost\"), None);
+        assert_eq!(p("C:/Users/me"), None);
+        assert_eq!(p("/home/me"), None);
+    }
+
+    fn utf16(s: &str) -> Vec<u8> {
+        std::iter::once(0xfeffu16).chain(s.encode_utf16()).flat_map(u16::to_le_bytes).collect()
+    }
+
+    #[test]
+    fn distro_list_is_decoded_from_utf16_and_utf8() {
+        let want = vec!["Ubuntu-24.04".to_owned(), "Debian".to_owned()];
+        assert_eq!(parse_distro_list(&utf16("Ubuntu-24.04\r\nDebian\r\n\r\n")), want);
+        assert_eq!(parse_distro_list(b"Ubuntu-24.04\nDebian\nDebian\n"), want);
+        assert!(
+            parse_distro_list(&utf16("Windows Subsystem for Linux has no installed distributions.\r\n")).is_empty()
+        );
+        assert!(parse_distro_list(b"").is_empty());
+    }
+
+    #[test]
+    fn distro_names_cannot_smuggle_options_or_paths() {
+        for bad in ["", "-d", "--exec", "a b", "a/b", r"a\b", "a;b", "a$(x)", "a\"b"] {
+            assert!(!is_valid_distro(bad), "{bad}");
+        }
+        assert!(is_valid_distro("Ubuntu-22.04") && is_valid_distro("docker_desktop"));
+    }
+}
@@ -1,8 +1,8 @@
 //! "Import a report collected in CI from disk": the format is sniffed from the
-//! content (lcov, Go cover profile, JaCoCo XML) and paths recorded on another
+//! content (lcov, Go cover profile, JaCoCo XML, SimpleCov resultset) and paths recorded on another
 //! machine are mapped into the project by their longest existing suffix.

-use crate::{Accumulator, CoverageSuite, goprofile, jacoco, lcov};
+use crate::{Accumulator, CoverageSuite, goprofile, jacoco, lcov, simplecov};
 use ide_core::{IdeError, IdeResult};
 use std::path::{Component, Path, PathBuf};

@@ -11,6 +11,7 @@ pub(crate) enum Format {
    Lcov,
    GoProfile,
    Jacoco,
+    SimpleCov,
 }

 pub(crate) fn detect(text: &str) -> Option<Format> {
@@ -18,6 +19,9 @@ pub(crate) fn detect(text: &str) -> Option<Format> {
    if head.starts_with('<') {
        return head.contains("<report").then_some(Format::Jacoco);
    }
+    if head.starts_with('{') {
+        return head.contains("\"coverage\"").then_some(Format::SimpleCov);
+    }
    let first = head.lines().next().unwrap_or_default();
    if first.starts_with("mode:") {
        return Some(Format::GoProfile);
@@ -30,6 +34,7 @@ pub fn import(path: &Path, root: &Path) -> IdeResult<CoverageSuite> {
    let text = std::fs::read_to_string(path)?;
    let mut suite = match detect(&text) {
        Some(Format::Lcov) => lcov::parse(&text, root).finish("lcov"),
+        Some(Format::SimpleCov) => simplecov::parse(&text, root)?.finish("SimpleCov"),
        Some(Format::GoProfile) => {
            let (module, module_dir) = go_module_for(root, &text);
            goprofile::parse(&text, &module, &module_dir).finish("go test -cover")
@@ -50,7 +55,7 @@ pub fn import(path: &Path, root: &Path) -> IdeResult<CoverageSuite> {
        }
        None => {
            return Err(IdeError::invalid(format!(
-                "{} is not an lcov tracefile, Go cover profile or JaCoCo XML report",
+                "{} is not an lcov tracefile, Go cover profile, JaCoCo XML report or SimpleCov resultset",
                path.display()
            )));
        }
@@ -125,9 +130,29 @@ mod tests {
            Some(Format::Jacoco)
        );
        assert_eq!(detect("<?xml version=\"1.0\"?><coverage/>"), None);
+        assert_eq!(detect("{\"RSpec\": {\"coverage\": {}}}"), Some(Format::SimpleCov));
+        assert_eq!(detect("{\"name\": \"package.json\"}"), None);
        assert_eq!(detect("hello"), None);
    }

+    #[test]
+    fn imports_ci_simplecov_with_foreign_paths() {
+        let tmp = tempfile::tempdir().unwrap();
+        let root = tmp.path().join("app");
+        std::fs::create_dir_all(root.join("lib")).unwrap();
+        std::fs::write(root.join("lib/a.rb"), "").unwrap();
+        let report = tmp.path().join(".resultset.json");
+        std::fs::write(
+            &report,
+            r#"{"RSpec":{"coverage":{"/home/runner/work/app/app/lib/a.rb":{"lines":[null,1,0]}}}}"#,
+        )
+        .unwrap();
+        let suite = import(&report, &root).unwrap();
+        assert_eq!(suite.runner, "SimpleCov");
+        assert_eq!(suite.files[0].path.as_ref() as &Path, root.join("lib/a.rb"));
+        assert_eq!((suite.files[0].lines_total, suite.files[0].lines_covered), (2, 1));
+    }
+
    #[test]
    fn imports_ci_lcov_with_foreign_paths() {
        let tmp = tempfile::tempdir().unwrap();
@@ -10,6 +10,7 @@
 //! | JS / TS (vitest, jest scripts) | the runner's `--coverage` | lcov |
 //! | Node.js scripts | `c8` | lcov |
 //! | Python (pytest, scripts) | coverage.py (`coverage run`, then `coverage lcov`) | lcov |
+//! | Ruby (rspec, minitest, rake, scripts) | SimpleCov (`coverage/.resultset.json`) | SimpleCov resultset |
 //! | Go (`go test`) | `-coverprofile` | Go cover profile |
 //! | Maven / Gradle tests | JaCoCo (plugin goals / an init script) | JaCoCo XML |
 //!
@@ -20,6 +21,7 @@ mod import;
 mod jacoco;
 mod lcov;
 mod plan;
+mod simplecov;

 pub use import::import;
 pub use plan::prepare;
@@ -83,6 +85,8 @@ pub enum CoverageReportSpec {
    Lcov { runner: String, path: IpcPath, base: IpcPath },
    /// `go test -coverprofile`; import paths under `module` map to `module_dir`.
    GoProfile { path: IpcPath, module: String, module_dir: IpcPath },
+    /// SimpleCov's `.resultset.json`; relative paths resolve against `base`.
+    SimpleCov { path: IpcPath, base: IpcPath },
    /// Every JaCoCo XML report (Maven `target/site/jacoco`, Gradle `build/reports/jacoco`) under `dir`.
    Jacoco { dir: IpcPath },
    /// The tool's raw data is exported to lcov by `argv` first (coverage.py: `… -m coverage lcov -o <lcov>`).
@@ -185,6 +189,10 @@ pub fn collect(spec: &CoverageReportSpec) -> IdeResult<CoverageSuite> {
            let text = read_report(path)?;
            Ok(lcov::parse(&text, base).finish(runner))
        }
+        CoverageReportSpec::SimpleCov { path, base } => {
+            let text = read_report(path)?;
+            Ok(simplecov::parse(&text, base)?.finish("SimpleCov"))
+        }
        CoverageReportSpec::GoProfile { path, module, module_dir } => {
            let text = read_report(path)?;
            Ok(goprofile::parse(&text, module, module_dir).finish("go test -cover"))
@@ -67,6 +67,7 @@ pub fn prepare(root: &Path, config: &RunConfig, out: &Path) -> CoveragePrepared
        "gradle" | "gradlew" => gradle(config, &dir, out),
        "npm" | "pnpm" | "yarn" | "bun" => npm(root, config, &dir, out),
        "node" | "npx" | "tsx" | "ts-node" => c8(root, config, &dir, out),
+        "ruby" | "bundle" | "rake" | "rspec" | "rails" => ruby(root, config, &dir, out),
        "deno" => unsupported("Coverage of Deno tasks is not supported yet."),
        "java" => unsupported(
            "Coverage of Java applications needs the JaCoCo agent; run a Maven or Gradle test configuration with coverage.",
@@ -234,6 +235,65 @@ fn c8(root: &Path, config: &RunConfig, dir: &Path, out: &Path) -> CoveragePrepar
    ready("c8", config, path(&c8), args, report)
 }

+/// Loaded first (`ide_run::ruby_preload`) when the project never starts SimpleCov itself.
+const SIMPLECOV_PRELOAD: &str = r#"# Written by OpenIDEA for Run with Coverage.
+begin
+  require "simplecov"
+rescue LoadError
+  # `bundle exec` is a Ruby process too and loads this before Bundler puts the project's gems on
+  # the load path; the Ruby it starts loads bundler/setup first and finds SimpleCov.
+  return
+end
+SimpleCov.coverage_dir(ENV.fetch("OPENIDEA_COVERAGE_DIR"))
+SimpleCov.start do
+  add_filter %r{^/(test|spec|features)/}
+  enable_coverage :branch
+end
+"#;
+
+/// Files where a project conventionally starts SimpleCov.
+const SIMPLECOV_STARTERS: &[&str] =
+    &[".simplecov", "spec/spec_helper.rb", "spec/rails_helper.rb", "test/test_helper.rb", "test/minitest_helper.rb"];
+
+fn ruby(root: &Path, config: &RunConfig, dir: &Path, out: &Path) -> CoveragePrepared {
+    let bundled = [dir, root].iter().any(|d| d.join("Gemfile").is_file());
+    let mentions = |file: &str| {
+        [dir, root].iter().any(|d| std::fs::read_to_string(d.join(file)).is_ok_and(|t| t.contains("simplecov")))
+    };
+    if bundled && !mentions("Gemfile.lock") && !mentions("Gemfile") {
+        return missing(
+            "simplecov",
+            "Ruby coverage needs the simplecov gem in the project's Gemfile.",
+            Some((vec![s("bundle"), s("add"), s("simplecov"), s("--group"), s("test")], dir)),
+        );
+    }
+    let starts = |d: &Path| {
+        SIMPLECOV_STARTERS.iter().any(|f| {
+            std::fs::read_to_string(d.join(f))
+                .is_ok_and(|t| t.contains("SimpleCov.start") || f.starts_with(".simplecov"))
+        })
+    };
+    let mut config = config.clone();
+    let resultset = if [dir, root].iter().any(|d| starts(d)) {
+        // The project's own configuration decides where the report goes (default `coverage/`).
+        // Drop the previous run's data: SimpleCov merges into it.
+        let results = dir.join("coverage");
+        let _ = std::fs::remove_file(results.join(".resultset.json"));
+        results.join(".resultset.json")
+    } else {
+        let preload = out.join("openidea_simplecov.rb");
+        if let Err(e) = std::fs::write(&preload, SIMPLECOV_PRELOAD) {
+            return unsupported(format!("Cannot write the SimpleCov preload: {e}"));
+        }
+        config.env.insert(s("OPENIDEA_COVERAGE_DIR"), path(out));
+        // `out` lives under the IDE's data directory, which may have spaces (RUBYOPT cannot take them).
+        ide_run::ruby_preload::add(&mut config.env, out, "openidea_simplecov", true);
+        out.join(".resultset.json")
+    };
+    let report = CoverageReportSpec::SimpleCov { path: resultset.into(), base: dir.to_path_buf().into() };
+    ready("SimpleCov", &config, config.command.clone(), config.args.clone(), report)
+}
+
 fn python(config: &RunConfig, dir: &Path, out: &Path, py: wrap::PythonCommand) -> CoveragePrepared {
    if py.target.is_empty() {
        return unsupported("Coverage needs a Python script or module to run.");
@@ -398,6 +458,74 @@ mod tests {
        ));
    }

+    /// `bundle exec` loads the preload before Bundler sets up the project's gems: without SimpleCov
+    /// on the load path it must step aside instead of failing the launcher.
+    #[test]
+    fn simplecov_preload_tolerates_a_ruby_without_the_gem() {
+        let dir = tempfile::tempdir().unwrap();
+        let out = dir.path().join("out dir");
+        std::fs::create_dir_all(&out).unwrap();
+        std::fs::write(out.join("openidea_simplecov.rb"), SIMPLECOV_PRELOAD).unwrap();
+        let status = std::process::Command::new("ruby")
+            .args(["-e", "exit 0"])
+            .env("RUBYLIB", &out)
+            .env("RUBYOPT", "-ropenidea_simplecov")
+            .env("OPENIDEA_COVERAGE_DIR", &out)
+            .env("GEM_HOME", dir.path().join("empty gems"))
+            .env("GEM_PATH", dir.path().join("empty gems"))
+            .status();
+        // No Ruby on this machine: nothing to check.
+        let Ok(status) = status else { return };
+        assert!(status.success());
+    }
+
+    #[test]
+    fn ruby_runs_get_simplecov() {
+        let dir = tempfile::tempdir().unwrap();
+        let root = dir.path();
+        // The IDE's data directory has spaces on macOS (`Application Support`).
+        let out = root.join("out dir");
+        std::fs::create_dir_all(&out).unwrap();
+        std::fs::write(root.join("Gemfile"), "source 'https://rubygems.org'\n").unwrap();
+        let config = cfg("rspec", "bundle", &["exec", "rspec"]);
+        // Bundler project without the gem: install hint.
+        match prepare(root, &config, &out) {
+            CoveragePrepared::MissingTool { tool, install: Some(i), .. } => {
+                assert_eq!(tool, "simplecov");
+                assert_eq!(i.args, ["add", "simplecov", "--group", "test"]);
+            }
+            other => panic!("{other:?}"),
+        }
+        // Gem present, never started: preloaded through RUBYOPT, report in `out`.
+        std::fs::write(root.join("Gemfile"), "gem 'simplecov'\n").unwrap();
+        let p = prepare(root, &config, &out);
+        let (l, report) = launch(&p);
+        assert_eq!(
+            (l.command.as_str(), l.args.as_slice()),
+            ("bundle", ["exec".to_owned(), "rspec".to_owned()].as_slice())
+        );
+        assert!(l.env["RUBYOPT"].contains("-ropenidea_simplecov"));
+        assert!(std::env::split_paths(&l.env["RUBYLIB"]).any(|d| d == out));
+        assert_eq!(l.env["OPENIDEA_COVERAGE_DIR"], out.to_string_lossy());
+        assert!(out.join("openidea_simplecov.rb").is_file());
+        assert!(
+            matches!(report, CoverageReportSpec::SimpleCov { path, .. } if (path.as_ref() as &Path).starts_with(&out))
+        );
+        // Started by the project: untouched environment, stale data dropped, report in `coverage/`.
+        std::fs::create_dir_all(root.join("test")).unwrap();
+        std::fs::create_dir_all(root.join("coverage")).unwrap();
+        std::fs::write(root.join("coverage/.resultset.json"), "{}").unwrap();
+        std::fs::write(root.join("test/test_helper.rb"), "require 'simplecov'\nSimpleCov.start\n").unwrap();
+        let p = prepare(root, &cfg("ruby", "ruby", &["-Ilib", "test/a_test.rb"]), &out);
+        let (l, report) = launch(&p);
+        assert!(!l.env.contains_key("RUBYOPT"));
+        assert_eq!(l.args, ["-Ilib", "test/a_test.rb"]);
+        assert!(!root.join("coverage/.resultset.json").exists());
+        assert!(
+            matches!(report, CoverageReportSpec::SimpleCov { path, .. } if (path.as_ref() as &Path).ends_with("coverage/.resultset.json"))
+        );
+    }
+
    #[test]
    fn unknown_commands_are_unsupported() {
        let dir = tempfile::tempdir().unwrap();
@@ -0,0 +1,74 @@
+//! SimpleCov's `coverage/.resultset.json`:
+//!
+//! ```json
+//! { "RSpec": { "timestamp": 1, "coverage": {
+//!     "/abs/lib/a.rb": { "lines": [null, 1, 0],
+//!                        "branches": { "[:if, 0, 3, 4, 3, 20]": { "[:then, 1, 4, 6, 4, 9]": 1, "[:else, 2, 6, 6, 6, 9]": 0 } } },
+//!     "/abs/lib/legacy.rb": [null, 1] } } }
+//! ```
+//!
+//! `lines[i]` is line `i + 1` (`null` = not relevant), so the index is already 0-based.
+//! A branch belongs to the line its condition starts on (third number of its key).
+
+use crate::Accumulator;
+use ide_core::{IdeError, IdeResult};
+use serde_json::Value;
+use std::path::Path;
+
+/// Start line (1-based) of a `"[:if, 0, 3, 4, 3, 20]"` branch key.
+fn start_line(key: &str) -> Option<u32> {
+    key.trim_matches(['[', ']']).split(',').nth(2)?.trim().parse().ok()
+}
+
+pub(crate) fn parse(text: &str, base: &Path) -> IdeResult<Accumulator> {
+    let json: Value = serde_json::from_str(text).map_err(|e| IdeError::invalid(format!("SimpleCov resultset: {e}")))?;
+    let mut acc = Accumulator::default();
+    // One entry per test command ("RSpec", "Minitest", …); their coverage is merged.
+    for suite in json.as_object().into_iter().flat_map(|o| o.values()) {
+        let Some(files) = suite.get("coverage").and_then(Value::as_object) else { continue };
+        for (name, data) in files {
+            let p = Path::new(name);
+            let path = if p.is_absolute() { p.to_path_buf() } else { base.join(p) };
+            acc.file(&path);
+            let lines = data.get("lines").or(Some(data)).and_then(Value::as_array);
+            for (i, hits) in lines.into_iter().flatten().enumerate() {
+                if let Some(hits) = hits.as_u64() {
+                    acc.line(&path, i as u32, hits);
+                }
+            }
+            for (cond, branches) in data.get("branches").and_then(Value::as_object).into_iter().flatten() {
+                let Some(line) = start_line(cond) else { continue };
+                for (branch, hits) in branches.as_object().into_iter().flatten() {
+                    acc.has_branches = true;
+                    acc.branch(&path, line.saturating_sub(1), format!("{cond}/{branch}"), hits.as_u64() > Some(0));
+                }
+            }
+        }
+    }
+    Ok(acc)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn reads_lines_branches_and_merges_suites() {
+        let text = r#"{
+          "RSpec": {"coverage": {"/p/lib/a.rb": {"lines": [null, 1, 0],
+            "branches": {"[:if, 0, 2, 4, 2, 20]": {"[:then, 1, 2, 6, 2, 9]": 1, "[:else, 2, 2, 6, 2, 9]": 0}}}}},
+          "Minitest": {"coverage": {"/p/lib/a.rb": {"lines": [null, 2, 3]}, "lib/old.rb": [1, null]}}
+        }"#;
+        let suite = parse(text, Path::new("/p")).unwrap().finish("SimpleCov");
+        assert_eq!(suite.files.len(), 2);
+        let a = suite.files.iter().find(|f| (f.path.as_ref() as &Path).ends_with("a.rb")).unwrap();
+        assert_eq!(a.lines.iter().map(|l| (l.line, l.hits)).collect::<Vec<_>>(), [(1, 3), (2, 3)]);
+        assert_eq!((a.branches_total, a.branches_covered), (2, 1));
+        assert_eq!(a.lines[0].branches_total, 2);
+        let old = suite.files.iter().find(|f| (f.path.as_ref() as &Path).ends_with("lib/old.rb")).unwrap();
+        assert_eq!(old.path.as_ref() as &Path, Path::new("/p/lib/old.rb"));
+        assert_eq!(old.lines[0].hits, 1);
+        assert!(suite.has_branches);
+        assert!(parse("nope", Path::new("/p")).is_err());
+    }
+}
@@ -8,7 +8,7 @@

 use ide_core::process::executable_names;
 use ide_core::{IdeError, IdeResult};
-use ide_language::{DebuggerConfig, LanguageRegistry};
+use ide_language::{DebuggerConfig, LanguageRegistry, ProgramPin};
 use std::future::Future;
 use std::path::{Path, PathBuf};
 use std::pin::Pin;
@@ -44,6 +44,8 @@ pub struct AdapterSpec {
    /// `host:port` of an adapter inside another program (the Godot editor): connected to
    /// when it accepts, else `command` is started.
    pub connect: Option<String>,
+    /// A plugin language's adapter: start exactly this approved program.
+    pub pinned: Option<ProgramPin>,
 }

 /// Built-in adapters used when no language definition names `adapter`.
@@ -55,6 +57,7 @@ fn builtin(adapter: &str) -> Option<DebuggerConfig> {
        transport: transport.to_owned(),
        connect: None,
        install_hint: Some(hint.to_owned()),
+        pinned: None,
    };
    Some(match adapter {
        "codelldb" => cfg(
@@ -69,7 +72,13 @@ fn builtin(adapter: &str) -> Option<DebuggerConfig> {
            "stdio",
            "Install the Kotlin Debug Adapter from Settings > Language Servers",
        ),
-        "debugpy" => cfg("python3", &["-m", "debugpy.adapter"], "stdio", "pip install debugpy"),
+        // Windows installs `python.exe`; `python3.exe` there is at most a Store alias.
+        "debugpy" => cfg(
+            if cfg!(windows) { "python" } else { "python3" },
+            &["-m", "debugpy.adapter"],
+            "stdio",
+            "pip install debugpy",
+        ),
        "js-debug" => cfg(
            "js-debug-adapter",
            // Without a host it listens on `localhost`, which may resolve to ::1 only.
@@ -133,6 +142,7 @@ pub fn resolve(config: &DebuggerConfig, cwd: PathBuf) -> AdapterSpec {
        env: Vec::new(),
        server_host: None,
        connect: config.connect.clone(),
+        pinned: config.pinned.clone(),
    }
 }

@@ -426,12 +436,20 @@ impl AdapterLauncher for ProcessLauncher {
            if is_plugin_bundle(&spec.command) {
                return Err(not_standalone(&spec));
            }
-            let (command, cwd) = (spec.command.clone(), spec.cwd.clone());
-            let binary = tokio::task::spawn_blocking(move || resolve_binary(&command, &cwd))
-                .await
-                .ok()
-                .flatten()
-                .ok_or_else(|| missing(&spec))?;
+            let binary = match spec.pinned.clone() {
+                Some(pin) => tokio::task::spawn_blocking(move || pin.verify().map(Path::to_path_buf))
+                    .await
+                    .map_err(|e| IdeError::internal(e.to_string()))?
+                    .map_err(|e| IdeError::new(ide_core::error::ErrorKind::PermissionDenied, e))?,
+                None => {
+                    let (command, cwd) = (spec.command.clone(), spec.cwd.clone());
+                    tokio::task::spawn_blocking(move || resolve_binary(&command, &cwd))
+                        .await
+                        .ok()
+                        .flatten()
+                        .ok_or_else(|| missing(&spec))?
+                }
+            };
            let port = match spec.transport {
                // An embedded adapter started without `${port}` listens on its usual address.
                Transport::Tcp => match &embedded {
@@ -212,6 +212,19 @@ pub struct Variable {
    pub evaluate_name: Option<String>,
 }

+/// A completion the adapter offers for an expression (DAP `completions`).
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize, Type)]
+#[serde(rename_all = "camelCase")]
+pub struct DebugCompletion {
+    pub label: String,
+    /// What to insert, when it differs from `label`.
+    pub text: Option<String>,
+    /// DAP item type: `method`, `field`, `variable`, `class`, `keyword`, …
+    pub kind: Option<String>,
+    pub detail: Option<String>,
+    pub sort_text: Option<String>,
+}
+
 #[derive(Clone, Copy, Debug, Serialize, Deserialize, Type)]
 #[serde(rename_all = "camelCase")]
 pub enum StepKind {
@@ -289,6 +302,23 @@ pub struct DebugManager {
    data_breakpoints: Mutex<Vec<DataBreakpoint>>,
 }

+/// Whether the debugged project depends on the Flutter SDK, so it must go
+/// through `flutter debug_adapter` instead of the plain Dart one.
+///
+/// `dart debug_adapter` cannot start a program that imports `dart:ui`, and only
+/// the Flutter adapter answers `hotReload` / `hotRestart`. `dir` is the launch
+/// `cwd`; the program's own directory is tried first because a module inside a
+/// larger repository has its `pubspec.yaml` above the program, not above `cwd`.
+fn is_flutter_project(dir: &Path, program: Option<&Path>) -> bool {
+    let mut start: Vec<&Path> = program.and_then(Path::parent).into_iter().collect();
+    start.push(dir);
+    start
+        .iter()
+        .filter_map(|d| d.ancestors().take(6).find(|a| a.join("pubspec.yaml").is_file()))
+        .filter_map(|root| std::fs::read_to_string(root.join("pubspec.yaml")).ok())
+        .any(|s| s.contains("sdk: flutter"))
+}
+
 fn no_session(s: DebugSessionId) -> IdeError {
    IdeError::not_found(format!("no debug session {}", s.0))
 }
@@ -557,6 +587,10 @@ impl DebugManager {
        custom_command: impl FnOnce(&str) -> Option<String>,
    ) -> IdeResult<DebugSessionId> {
        let mut arguments = launch_arguments(&config)?;
+        // An IDE-side marker (never sent to the adapter): the session is a Flutter
+        // one regardless of what the working directory holds.
+        let force_flutter =
+            arguments.as_object_mut().and_then(|o| o.remove("__flutter")).and_then(|v| v.as_bool()).unwrap_or(false);
        let cwd = config
            .cwd
            .clone()
@@ -576,17 +610,27 @@ impl DebugManager {
        if let Some(command) = custom_command(&spec.command) {
            spec.command = command;
        }
-        // debugpy: run the adapter with the debuggee's interpreter (venvs carry their own debugpy).
+        // debugpy: run the adapter with the debuggee's interpreter (venvs carry their own debugpy),
+        // or with the launcher's when the debuggee runs through a manager (`uv run python`).
        if config.adapter == "debugpy" {
-            let python = match arguments.get("python") {
-                Some(Value::String(p)) => Some(p.clone()),
-                Some(Value::Array(a)) => a.first().and_then(Value::as_str).map(str::to_owned),
+            let python = match (arguments.get("debugLauncherPython"), arguments.get("python")) {
+                (Some(Value::String(p)), _) | (_, Some(Value::String(p))) => Some(p.clone()),
+                (_, Some(Value::Array(a))) => a.first().and_then(Value::as_str).map(str::to_owned),
                _ => None,
            };
            if let Some(python) = python {
                spec.command = python;
            }
        }
+        // Flutter: a project depending on the Flutter SDK needs `flutter debug_adapter`
+        // (the Dart adapter cannot start a program importing `dart:ui`, and hot reload
+        // is Flutter-only). Plain Dart projects keep the configured `dart`.
+        if config.adapter == "dart" && spec.command == "dart" {
+            let program = arguments.get("program").and_then(Value::as_str).map(Path::new);
+            if force_flutter || is_flutter_project(&cwd, program) {
+                spec.command = "flutter".into();
+            }
+        }
        let id = DebugSessionId::next();
        let debug_server = take_debug_server(&mut arguments)?;
        if let Some(server) = &debug_server {
@@ -638,8 +682,19 @@ impl DebugManager {
        {
            arguments["project"] = json!(real);
        }
-        if config.adapter == "codelldb" && arguments.get("sourceLanguages").is_none() {
-            arguments["sourceLanguages"] = json!(["rust"]);
+        if config.adapter == "codelldb" {
+            if arguments.get("sourceLanguages").is_none() {
+                arguments["sourceLanguages"] = json!(["rust"]);
+            }
+            // The Debug Console and Evaluate Expression take expressions, as with every other
+            // debugger; LLDB commands still run with a leading backtick.
+            match arguments.get_mut("_adapterSettings") {
+                None => arguments["_adapterSettings"] = json!({"consoleMode": "evaluate"}),
+                Some(Value::Object(settings)) => {
+                    settings.entry("consoleMode").or_insert_with(|| json!("evaluate"));
+                }
+                Some(_) => {}
+            }
        }
        let port = debug_server.map(|s| s.port);
        self.start_session(id, owner, config.name, config.adapter, None, config.request, arguments, spec, port).await
@@ -1157,6 +1212,47 @@ impl DebugManager {
        })
    }

+    /// Completions for `text` at `line` / `column` (0-based, UTF-16) in the frame's scope; none
+    /// when the adapter doesn't offer them.
+    pub async fn completions(
+        &self,
+        s: DebugSessionId,
+        frame_id: Option<i64>,
+        text: String,
+        line: u32,
+        column: u32,
+    ) -> IdeResult<Vec<DebugCompletion>> {
+        let session = self.session(s)?;
+        if !session.supports("supportsCompletionsRequest") {
+            return Ok(Vec::new());
+        }
+        let mut args = json!({ "text": text, "line": line + 1, "column": column + 1 });
+        if let Some(f) = frame_id {
+            args["frameId"] = f.into();
+        }
+        let body = session.conn.request_timeout("completions", args, REQUEST_TIMEOUT).await?;
+        let text =
+            |v: &Value, key: &str| v.get(key).and_then(Value::as_str).filter(|t| !t.is_empty()).map(str::to_owned);
+        Ok(body
+            .get("targets")
+            .and_then(Value::as_array)
+            .map(|targets| {
+                targets
+                    .iter()
+                    .filter_map(|t| {
+                        Some(DebugCompletion {
+                            label: text(t, "label")?,
+                            text: text(t, "text"),
+                            kind: text(t, "type"),
+                            detail: text(t, "detail"),
+                            sort_text: text(t, "sortText"),
+                        })
+                    })
+                    .collect()
+            })
+            .unwrap_or_default())
+    }
+
    pub async fn resume(&self, s: DebugSessionId, thread_id: i64) -> IdeResult<()> {
        let session = self.session(s)?;
        let body = session.conn.request_timeout("continue", json!({ "threadId": thread_id }), REQUEST_TIMEOUT).await?;
@@ -1170,6 +1266,19 @@ impl DebugManager {
        Ok(())
    }

+    /// Flutter's DAP adapter: injects the changed sources into the running app.
+    /// Not part of the DAP standard; adapters that do not know the request reject it.
+    pub async fn hot_reload(&self, s: DebugSessionId) -> IdeResult<()> {
+        self.session(s)?.conn.request_timeout("hotReload", json!({ "reason": "manual" }), REQUEST_TIMEOUT).await?;
+        Ok(())
+    }
+
+    /// Flutter's DAP adapter: restarts the app without preserving state.
+    pub async fn hot_restart(&self, s: DebugSessionId) -> IdeResult<()> {
+        self.session(s)?.conn.request_timeout("hotRestart", json!({ "reason": "manual" }), REQUEST_TIMEOUT).await?;
+        Ok(())
+    }
+
    pub async fn step(&self, s: DebugSessionId, thread_id: i64, kind: StepKind) -> IdeResult<()> {
        let command = match kind {
            StepKind::Over => "next",
@@ -1389,6 +1498,16 @@ impl DebugManager {
        })
    }

+    /// Stops every session `key` started: the window that opened the project is closing.
+    pub async fn stop_key(&self, key: &str) {
+        let ids: Vec<DebugSessionId> = self.sessions(Some(key)).into_iter().map(|s| s.id).collect();
+        for id in ids {
+            if let Err(e) = self.stop(id).await {
+                tracing::debug!("debug session {id:?} did not stop: {e}");
+            }
+        }
+    }
+
    /// Stops a session and its child sessions.
    pub async fn stop(&self, s: DebugSessionId) -> IdeResult<()> {
        let session = self.session(s)?;
@@ -111,8 +111,8 @@ impl Session {
        if let Some(path) = self.kotlin_mirror.lock().as_ref().and_then(|m| m.adapter_path(path)) {
            return path;
        }
-        if self.adapter == "java-debug" {
-            let native = java_source_path(&path.to_string_lossy());
+        if self.adapter == "java-debug" || (cfg!(windows) && self.adapter == "netcoredbg") {
+            let native = windows_source_path(&path.to_string_lossy());
            self.resolved_paths.lock().insert(native.clone(), path.to_path_buf());
            return native;
        }
@@ -133,7 +133,11 @@ impl Session {
        if let Some(real) = self.kotlin_mirror.lock().as_ref().and_then(|m| m.client_path(Path::new(path))) {
            return Some(real);
        }
-        let key = if self.adapter == "java-debug" { java_source_path(path) } else { PathBuf::from(path) };
+        let key = if self.adapter == "java-debug" || (cfg!(windows) && self.adapter == "netcoredbg") {
+            windows_source_path(path)
+        } else {
+            PathBuf::from(path)
+        };
        self.resolved_paths.lock().get(&key).cloned().or_else(|| {
            (self.adapter == "java-debug" && is_windows_source_path(path))
                .then(|| PathBuf::from(path.replace('\\', "/")))
@@ -265,8 +269,8 @@ impl Session {
    }
 }

-// java-debug treats a forward-slash drive path as a URI (scheme "C").
-// Keep DAP path mode, but use native Windows separators for Java source lookup.
+// java-debug and Windows netcoredbg need native separators for source lookup.
+// Keep DAP path mode, but normalize Windows drive and UNC paths.
 fn is_windows_source_path(path: &str) -> bool {
    let bytes = path.as_bytes();
    (bytes.len() >= 3 && bytes[0].is_ascii_alphabetic() && bytes[1] == b':' && matches!(bytes[2], b'/' | b'\\'))
@@ -274,7 +278,7 @@ fn is_windows_source_path(path: &str) -> bool {
        || path.starts_with(r"\\")
 }

-fn java_source_path(path: &str) -> PathBuf {
+fn windows_source_path(path: &str) -> PathBuf {
    if is_windows_source_path(path) { PathBuf::from(path.replace('/', r"\")) } else { PathBuf::from(path) }
 }

@@ -405,7 +409,7 @@ async fn on_event(mgr: &Arc<DebugManager>, s: &Arc<Session>, event: &str, mut bo
                let mut progress = s.progress.lock();
                let id =
                    if done { progress.remove(&pid) } else { Some(*progress.entry(pid).or_insert_with(TaskId::next)) };
-                (id, str_("title").unwrap_or_else(|| s.name.clone()))
+                (id, str_("title").map(|t| ide_core::task::display_title(&t)).unwrap_or_else(|| s.name.clone()))
            };
            let Some(id) = id else { return };
            s.owner.sink.emit(IdeEvent::Task {
@@ -73,6 +73,7 @@ async fn fake_adapter<S: AsyncRead + AsyncWrite + Unpin + Send + 'static>(stream
                msg,
                json!({
                    "supportsConfigurationDoneRequest": true,
+                    "supportsCompletionsRequest": true,
                    "supportsTerminateRequest": true,
                    "supportsSetVariable": true,
                    "supportsFunctionBreakpoints": true,
@@ -172,6 +173,14 @@ async fn fake_adapter<S: AsyncRead + AsyncWrite + Unpin + Send + 'static>(stream
                ]})
            ),
            "evaluate" => ok!(msg, json!({"result": "42", "type": "int", "variablesReference": 0})),
+            "completions" => ok!(
+                msg,
+                json!({"targets": [
+                    {"label": "getName()", "text": "getName", "type": "method", "detail": "String"},
+                    {"label": "name", "type": "field"},
+                    {"label": ""},
+                ]})
+            ),
            "continue" => {
                ok!(msg, json!({"allThreadsContinued": true}));
                send!(json!({"type": "event", "event": "exited", "body": {"exitCode": 3}}));
@@ -368,6 +377,14 @@ async fn full_protocol_flow() {
    let eval = h.request("evaluate");
    assert_eq!(eval["arguments"]["context"], "watch");
    assert_eq!(eval["arguments"]["frameId"], 10);
+    let items = h.manager.completions(id, Some(10), "req.na".into(), 0, 6).await.unwrap();
+    assert_eq!(
+        items.iter().map(|c| (c.label.as_str(), c.text.as_deref(), c.kind.as_deref())).collect::<Vec<_>>(),
+        [("getName()", Some("getName"), Some("method")), ("name", None, Some("field"))]
+    );
+    let asked = h.request("completions");
+    assert_eq!((asked["arguments"]["line"].clone(), asked["arguments"]["column"].clone()), (json!(1), json!(7)));
+    assert_eq!(asked["arguments"]["frameId"], 10);

    // Live breakpoint updates reach the session.
    let states = h.manager.set_breakpoints(path.clone(), vec![bp(0)]).await.unwrap();
@@ -681,6 +698,37 @@ async fn js_debug_launch_gets_port_and_workspace_folder() {
    assert_eq!(launch["type"], "pwa-node");
 }

+/// CodeLLDB treats console input as LLDB commands unless told otherwise: Evaluate Expression
+/// and the Debug Console send expressions, so its console evaluates them. A launch
+/// configuration that picks a console mode keeps it.
+#[tokio::test]
+async fn codelldb_console_evaluates_expressions() {
+    let launch_with = |extra: Value| async move {
+        let h = harness(Script::default());
+        let config = LaunchConfig {
+            name: "demo".into(),
+            adapter: "codelldb".into(),
+            request: "launch".into(),
+            program: Some("/p/target/debug/demo".into()),
+            args: vec![],
+            cwd: Some("/p".into()),
+            env: BTreeMap::new(),
+            extra_json: Some(extra.to_string()),
+        };
+        h.start(config).await.unwrap();
+        h.request("launch")["arguments"].clone()
+    };
+    let launch = launch_with(json!({})).await;
+    assert_eq!(launch["_adapterSettings"]["consoleMode"], "evaluate");
+    assert_eq!(launch["sourceLanguages"], json!(["rust"]));
+
+    let launch =
+        launch_with(json!({"_adapterSettings": {"consoleMode": "commands", "showDisassembly": "never"}})).await;
+    assert_eq!(launch["_adapterSettings"], json!({"consoleMode": "commands", "showDisassembly": "never"}));
+    let launch = launch_with(json!({"_adapterSettings": {"showDisassembly": "never"}})).await;
+    assert_eq!(launch["_adapterSettings"], json!({"consoleMode": "evaluate", "showDisassembly": "never"}));
+}
+
 /// An adapter that is already listening (java-debug inside jdtls): the client
 /// connects over TCP to the `debugServer` port instead of spawning anything.
 #[tokio::test]
@@ -906,6 +954,7 @@ fn godot_registry(port: u16, command: &str, args: &[&str]) -> Arc<LanguageRegist
        ui_mode: None,
        framework_ui_modes: Vec::new(),
        formatter: None,
+        scratch_template: None,
        tree_sitter: None,
        language_servers: vec![],
        debugger: Some(ide_language::DebuggerConfig {
@@ -915,6 +964,7 @@ fn godot_registry(port: u16, command: &str, args: &[&str]) -> Arc<LanguageRegist
            transport: "tcp".into(),
            connect: Some(format!("127.0.0.1:{port}")),
            install_hint: Some("Open the project in the Godot editor".into()),
+            pinned: None,
        }),
    };
    Arc::new(LanguageRegistry::from_configs(vec![lang]))
@@ -1091,6 +1141,23 @@ async fn kotlin_official_release_ten_no_delay_runs() {
    }
 }

+#[cfg(windows)]
+#[tokio::test]
+async fn netcoredbg_windows_source_paths_round_trip() {
+    let client = "D:/work/LoginController.cs";
+    let native = r"D:\work\LoginController.cs";
+    let h = harness(Script { source_path: Some(native.into()), ..Script::default() });
+    let path = PathBuf::from(client);
+    h.manager.set_breakpoints(path.clone(), vec![bp(25)]).await.unwrap();
+    let mut cfg = config();
+    cfg.adapter = "netcoredbg".into();
+    let id = h.start(cfg).await.unwrap();
+    assert_eq!(h.request("setBreakpoints")["arguments"]["source"]["path"], native);
+    let frames = h.manager.stack_trace(id, 1).await.unwrap();
+    assert_eq!(frames[0].path.as_deref(), Some(path.as_path()));
+    h.manager.stop(id).await.unwrap();
+}
+
 #[tokio::test]
 async fn java_windows_source_paths_for_launch_and_attach() {
    for request in ["launch", "attach"] {
@@ -1147,3 +1214,74 @@ async fn java_stack_frames_without_breakpoints_normalize_windows_paths() {
        h.manager.stop(id).await.unwrap();
    }
 }
+
+/// A built-in language definition (GDScript) shipped by a plugin
+/// instead: its debugger starts the program approved for the plugin's
+/// `process:godot` grant, and refuses once that file changed.
+#[cfg(unix)]
+#[tokio::test]
+async fn a_plugin_language_runs_its_debug_adapter_from_the_approved_program() {
+    use ide_language::ProgramPin;
+    use ide_language::plugin_point::{PluginLanguages, parse_definition};
+    use std::os::unix::fs::PermissionsExt;
+
+    let dir = std::env::temp_dir().join(format!("openidea-plugin-dap-{}", std::process::id()));
+    std::fs::create_dir_all(&dir).unwrap();
+    // Stands in for `godot --headless --editor …`.
+    let program = dir.join("godot");
+    std::fs::write(&program, "#!/bin/sh\nexec sleep 30\n").unwrap();
+    std::fs::set_permissions(&program, std::fs::Permissions::from_mode(0o755)).unwrap();
+
+    let port = std::net::TcpListener::bind(("127.0.0.1", 0)).unwrap().local_addr().unwrap().port();
+    let mut gdscript = parse_definition(include_str!("../../../languages/gdscript.toml")).unwrap();
+    let debugger = gdscript.debugger.as_mut().unwrap();
+    debugger.args.clear();
+    debugger.connect = Some(format!("127.0.0.1:{port}"));
+
+    // No built-in GDScript: it comes from the plugin.
+    let registry = Arc::new(LanguageRegistry::from_configs(Vec::new()));
+    let store = PluginLanguages::new();
+    registry.attach_plugins(store.clone());
+    let pin = ProgramPin::approve(&program).unwrap();
+    store.set_process_policy(Arc::new(move |plugin, cap| {
+        (plugin == "acme.godot" && cap.to_string() == "process:godot").then(|| pin.clone())
+    }));
+    let _language = store.add("acme.godot".into(), gdscript);
+
+    let log: Log = Arc::default();
+    let server_log = log.clone();
+    tokio::spawn(async move {
+        tokio::time::sleep(std::time::Duration::from_millis(300)).await;
+        let listener = tokio::net::TcpListener::bind(("127.0.0.1", port)).await.unwrap();
+        let (stream, _) = listener.accept().await.unwrap();
+        fake_adapter(stream, server_log, Script::default()).await;
+    });
+    let (owner, _events) = recording_owner("main");
+    let manager = DebugManager::new(registry.clone());
+    let id = manager.start(godot_launch(&dir), owner).await.unwrap();
+    assert!(log.lock().iter().any(|m| m["command"] == "launch"));
+    manager.stop(id).await.unwrap();
+
+    // Replaced after approval: refused before anything starts.
+    std::fs::write(&program, "#!/bin/sh\nexec sleep 31\n").unwrap();
+    let (owner, _events) = recording_owner("main");
+    let err = manager.start(godot_launch(&dir), owner).await.unwrap_err();
+    assert_eq!(err.kind, ide_core::error::ErrorKind::PermissionDenied, "{}", err.message);
+    let _ = std::fs::remove_dir_all(&dir);
+}
+
+#[test]
+fn flutter_projects_are_found_from_the_program_or_the_working_directory() {
+    let root = std::env::temp_dir().join(format!("openidea-flutter-{}", std::process::id()));
+    let app = root.join("app");
+    let tool = root.join("tool");
+    std::fs::create_dir_all(app.join("lib")).unwrap();
+    std::fs::create_dir_all(tool.join("bin")).unwrap();
+    std::fs::write(app.join("pubspec.yaml"), "name: app\ndependencies:\n  flutter:\n    sdk: flutter\n").unwrap();
+    std::fs::write(tool.join("pubspec.yaml"), "name: tool\ndependencies:\n  args: ^2.0.0\n").unwrap();
+    assert!(is_flutter_project(&app, None));
+    assert!(is_flutter_project(&root, Some(&app.join("lib/main.dart"))));
+    assert!(!is_flutter_project(&tool, Some(&tool.join("bin/main.dart"))));
+    assert!(!is_flutter_project(&root, None));
+    std::fs::remove_dir_all(&root).unwrap();
+}
@@ -8,7 +8,7 @@ license.workspace = true
 [dependencies]
 ide-core.workspace = true
 serde.workspace = true
-serde_json.workspace = true
+serde_json = { workspace = true, features = ["raw_value"] }
 specta.workspace = true
 toml.workspace = true
 tokio.workspace = true
@@ -21,7 +21,12 @@ bb8.workspace = true
 tokio-util = { workspace = true, features = ["compat"] }
 dirs.workspace = true
 ide-ssh.workspace = true
+ide-http.workspace = true
+reqwest = { workspace = true, features = ["query"] }
+rustls.workspace = true
+uuid.workspace = true

 [dev-dependencies]
 tokio = { workspace = true, features = ["rt-multi-thread", "macros"] }
 tempfile.workspace = true
+ide-ssh = { workspace = true, features = ["testing"] }
@@ -0,0 +1,889 @@
+use crate::conn::{QueryResult, ResultColumn, Setup};
+use crate::source::{DataSource, DbSslMode, DbTxMode};
+use ide_core::{CancellationToken, IdeError, IdeResult, error::ErrorKind};
+use parking_lot::RwLock;
+use reqwest::{Client, RequestBuilder, StatusCode, Url};
+use std::sync::Arc;
+use std::time::{Duration, Instant};
+use tokio::sync::Mutex;
+
+#[derive(Clone)]
+pub struct ClickhousePool(Arc<State>);
+
+struct State {
+    client: RwLock<Option<Client>>,
+    endpoint: Url,
+    user: String,
+    password: String,
+    database: String,
+    settings: Vec<(String, String)>,
+    read_only: bool,
+    session_id: String,
+    session: Mutex<bool>,
+    closed: CancellationToken,
+}
+
+/// The response format: a names line, a types line, then one JSON array per row, so rows past
+/// the grid's limit are skipped without being parsed.
+const FORMAT: &str = "JSONCompactEachRowWithNamesAndTypes";
+
+pub(crate) fn transaction_error() -> IdeError {
+    IdeError::invalid("ClickHouse HTTP does not support SQL transactions; use auto-commit and run writes directly")
+}
+
+impl ClickhousePool {
+    pub(crate) async fn connect(source: &DataSource, password: Option<&str>, setup: Setup) -> IdeResult<Self> {
+        if source.options.transaction == DbTxMode::Manual {
+            return Err(transaction_error());
+        }
+        for (name, _) in &setup.params {
+            if reserved_setting(name) {
+                return Err(IdeError::invalid(format!("ClickHouse HTTP manages the {name} setting")));
+            }
+        }
+        let secure = matches!(source.ssl, DbSslMode::Require | DbSslMode::VerifyCa | DbSslMode::VerifyFull);
+        let tls_files = [&source.ssl_ca_file, &source.ssl_cert_file, &source.ssl_key_file];
+        if !secure && tls_files.iter().any(|p| !p.trim().is_empty()) {
+            return Err(IdeError::invalid(
+                "ClickHouse TLS certificate files require an SSL mode of Require, Verify CA, or Verify Full",
+            ));
+        }
+        let host = source.host.trim();
+        if host.is_empty() || host.contains(['/', '@', '?', '#']) {
+            return Err(IdeError::invalid("ClickHouse host must contain only a hostname or IP address"));
+        }
+        let host = if host.contains(':') && !host.starts_with('[') { format!("[{host}]") } else { host.to_owned() };
+        let scheme = if secure { "https" } else { "http" };
+        let port = source.port.unwrap_or(if secure { 8443 } else { 8123 });
+        let endpoint = Url::parse(&format!("{scheme}://{host}:{port}/"))
+            .map_err(|_| IdeError::invalid("invalid ClickHouse HTTP host or port"))?;
+        let timeout = setup.connect_timeout.unwrap_or(Duration::from_secs(30));
+        let _ = rustls::crypto::ring::default_provider().install_default();
+        let mut builder = Client::builder()
+            .connect_timeout(timeout)
+            .pool_max_idle_per_host(4)
+            .redirect(reqwest::redirect::Policy::none())
+            .user_agent(concat!("OpenIDEA/", env!("CARGO_PKG_VERSION")));
+        let ca = source.ssl_ca_file.trim();
+        if !ca.is_empty() {
+            let pem = read_pem(ca, "CA certificate")?;
+            let certificates = reqwest::Certificate::from_pem_bundle(&pem)
+                .map_err(|_| IdeError::invalid("invalid ClickHouse CA certificate PEM"))?;
+            if certificates.is_empty() {
+                return Err(IdeError::invalid("ClickHouse CA certificate PEM contains no certificates"));
+            }
+            builder = builder.tls_certs_only(certificates);
+        }
+        if source.ssl == DbSslMode::VerifyCa {
+            if ca.is_empty() {
+                return Err(IdeError::invalid("ClickHouse Verify CA requires a CA certificate file"));
+            }
+            builder = builder.tls_danger_accept_invalid_hostnames(true);
+        }
+        let cert = source.ssl_cert_file.trim();
+        let key = source.ssl_key_file.trim();
+        if cert.is_empty() != key.is_empty() {
+            return Err(IdeError::invalid("ClickHouse client TLS requires both certificate and key files"));
+        }
+        if !cert.is_empty() {
+            let mut pem = read_pem(cert, "client certificate")?;
+            pem.push(b'\n');
+            pem.extend(read_pem(key, "client key")?);
+            let identity = reqwest::Identity::from_pem(&pem)
+                .map_err(|_| IdeError::invalid("invalid ClickHouse client certificate or key PEM"))?;
+            builder = builder.identity(identity);
+        }
+        let proxy = ide_core::proxy_settings::proxy();
+        let client = ide_http::client::with_proxy(builder, &proxy).build().map_err(http_error)?;
+        let database = if source.options.default_schema.trim().is_empty() {
+            source.database.trim()
+        } else {
+            source.options.default_schema.trim()
+        };
+        let pool = Self(Arc::new(State {
+            client: RwLock::new(Some(client)),
+            endpoint,
+            user: if source.user.is_empty() { "default".into() } else { source.user.clone() },
+            password: password.unwrap_or_default().to_owned(),
+            database: if database.is_empty() { "default".into() } else { database.into() },
+            settings: setup.params,
+            read_only: source.read_only,
+            session_id: uuid::Uuid::new_v4().to_string(),
+            session: Mutex::new(false),
+            closed: CancellationToken::new(),
+        }));
+        let cancel = CancellationToken::new();
+        let initialize = async {
+            pool.execute("SELECT 1", 1, &cancel).await?;
+            for sql in setup.statements {
+                pool.execute(&sql, 0, &cancel).await?;
+            }
+            Ok(pool.clone())
+        };
+        tokio::pin!(initialize);
+        tokio::select! {
+            result = &mut initialize => {
+                if result.is_err() {
+                    pool.close();
+                }
+                result
+            },
+            () = tokio::time::sleep(timeout) => {
+                cancel.cancel();
+                let _ = initialize.await;
+                pool.close();
+                Err(IdeError::new(ErrorKind::TimedOut, "timed out connecting to ClickHouse HTTP"))
+            }
+        }
+    }
+
+    pub fn close(&self) {
+        self.0.closed.cancel();
+        self.0.client.write().take();
+    }
+
+    pub fn is_closed(&self) -> bool {
+        self.0.closed.is_cancelled()
+    }
+
+    fn client(&self) -> IdeResult<Client> {
+        self.0.client.read().clone().ok_or_else(|| IdeError::new(ErrorKind::Io, "ClickHouse connection is closed"))
+    }
+
+    /// `max_rows`: the rows the server may send (the skipped ones included).
+    fn request(&self, client: &Client, query_id: &str, max_rows: usize, initialized: bool) -> RequestBuilder {
+        let mut request = client
+            .post(self.0.endpoint.clone())
+            .basic_auth(&self.0.user, Some(&self.0.password))
+            .header(reqwest::header::CONTENT_TYPE, "text/plain; charset=utf-8")
+            .query(&self.0.settings)
+            .query(&[
+                ("session_id", self.0.session_id.clone()),
+                ("session_timeout", "3600".into()),
+                ("query_id", query_id.to_owned()),
+                ("default_format", FORMAT.into()),
+                ("output_format_json_quote_denormals", "1".into()),
+                ("max_result_rows", max_rows.saturating_add(1).to_string()),
+                ("result_overflow_mode", "break".into()),
+            ]);
+        if initialized {
+            request = request.query(&[("session_check", "1")]);
+        } else {
+            request = request.query(&[("database", &self.0.database)]);
+        }
+        if self.0.read_only {
+            request = request.query(&[("readonly", "1")]);
+        }
+        request
+    }
+
+    pub async fn execute(&self, sql: &str, max_rows: usize, cancel: &CancellationToken) -> IdeResult<QueryResult> {
+        self.execute_from(sql, 0, max_rows, cancel).await
+    }
+
+    /// [`execute`](Self::execute), reading past the first `skip` rows without parsing or keeping them.
+    pub async fn execute_from(
+        &self,
+        sql: &str,
+        skip: usize,
+        max_rows: usize,
+        cancel: &CancellationToken,
+    ) -> IdeResult<QueryResult> {
+        if transaction_statement(sql) {
+            return Err(transaction_error());
+        }
+        let mut session = tokio::select! {
+            biased;
+            () = cancel.cancelled() => return Err(IdeError::cancelled()),
+            () = self.0.closed.cancelled() => return Err(IdeError::new(ErrorKind::Io, "ClickHouse connection is closed")),
+            session = self.0.session.lock() => session,
+        };
+        let client = self.client()?;
+        let query_id = uuid::Uuid::new_v4().to_string();
+        let request = self.request(&client, &query_id, skip.saturating_add(max_rows), *session).body(sql.to_owned());
+        let started = Instant::now();
+        let fetch = async {
+            let mut response = request.send().await.map_err(http_error)?;
+            let execution_ms = started.elapsed().as_secs_f64() * 1000.0;
+            let status = response.status();
+            let header = |name: &str| response.headers().get(name).and_then(|v| v.to_str().ok()).map(str::to_owned);
+            let exception_code = header("X-ClickHouse-Exception-Code");
+            let format = header("X-ClickHouse-Format");
+            let affected = header("X-ClickHouse-Summary")
+                .and_then(|v| serde_json::from_str::<serde_json::Value>(&v).ok())
+                .and_then(|v| {
+                    v.get("written_rows")
+                        .and_then(|n| n.as_str().and_then(|n| n.parse::<u64>().ok()).or_else(|| n.as_u64()))
+                });
+            if !status.is_success() || exception_code.as_deref().is_some_and(|code| code != "0") {
+                let body = response.bytes().await.map_err(http_error)?;
+                return Err(self.server_error(status, exception_code.as_deref(), &body));
+            }
+            let (columns, rows, has_more) = if format.as_deref().is_some_and(|f| f != FORMAT) {
+                let body = response.bytes().await.map_err(http_error)?;
+                if !body.iter().all(u8::is_ascii_whitespace) {
+                    return Err(IdeError::invalid(
+                        "ClickHouse result grids need the default output format; remove the query's FORMAT clause",
+                    ));
+                }
+                (Vec::new(), Vec::new(), false)
+            } else {
+                let mut reader = RowReader::new(skip, max_rows);
+                while let Some(chunk) = response.chunk().await.map_err(http_error)? {
+                    reader.push(&chunk)?;
+                }
+                reader.finish().map_err(|error| self.redact_error(error))?
+            };
+            let affected = if columns.is_empty() { affected.map(|n| n as f64) } else { None };
+            Ok(QueryResult {
+                statement: sql.to_owned(),
+                columns,
+                rows,
+                affected,
+                has_more,
+                elapsed_ms: started.elapsed().as_secs_f64() * 1000.0,
+                execution_ms,
+            })
+        };
+        let result = tokio::select! {
+            biased;
+            () = cancel.cancelled() => None,
+            () = self.0.closed.cancelled() => None,
+            result = fetch => Some(result),
+        };
+        match result {
+            Some(result) => {
+                if result.is_ok() {
+                    *session = true;
+                }
+                result
+            }
+            None => {
+                let killed = self.kill(&client, &query_id).await;
+                match killed {
+                    Ok(()) => Err(IdeError::cancelled()),
+                    Err(error) => Err(IdeError::new(
+                        ErrorKind::Cancelled,
+                        format!("cancelled locally; ClickHouse server cancellation failed: {}", error.message),
+                    )),
+                }
+            }
+        }
+    }
+
+    async fn kill(&self, client: &Client, query_id: &str) -> IdeResult<()> {
+        let response = client
+            .post(self.0.endpoint.clone())
+            .basic_auth(&self.0.user, Some(&self.0.password))
+            .timeout(Duration::from_secs(3))
+            .body(format!("KILL QUERY WHERE query_id = '{query_id}' SYNC"))
+            .send()
+            .await
+            .map_err(http_error)?;
+        let status = response.status();
+        let code = response
+            .headers()
+            .get("X-ClickHouse-Exception-Code")
+            .and_then(|value| value.to_str().ok())
+            .map(str::to_owned);
+        let body = response.bytes().await.map_err(http_error)?;
+        if status.is_success() && !code.as_deref().is_some_and(|code| code != "0") && !body.starts_with(b"Code:") {
+            Ok(())
+        } else {
+            Err(self.server_error(status, code.as_deref(), &body))
+        }
+    }
+
+    fn redact_error(&self, mut error: IdeError) -> IdeError {
+        if !self.0.password.is_empty() {
+            error.message = error.message.replace(&self.0.password, "[redacted]");
+        }
+        error
+    }
+
+    fn server_error(&self, status: StatusCode, code: Option<&str>, body: &[u8]) -> IdeError {
+        let message = String::from_utf8_lossy(body);
+        let message: String = exception_text(&message).chars().take(16_384).collect();
+        let auth = matches!(status, StatusCode::UNAUTHORIZED | StatusCode::FORBIDDEN)
+            || matches!(code, Some("193" | "194" | "195" | "516" | "497"));
+        let detail = if message.is_empty() { status.canonical_reason().unwrap_or("request failed") } else { &message };
+        let detail = if detail.contains("SESSION_NOT_FOUND") || detail.contains("Session not found") {
+            "ClickHouse HTTP session expired; reconnect to restore session settings"
+        } else {
+            detail
+        };
+        self.redact_error(IdeError::new(
+            if auth { ErrorKind::PermissionDenied } else { ErrorKind::InvalidInput },
+            format!("ClickHouse HTTP {}: {detail}", status.as_u16()),
+        ))
+    }
+}
+
+type DecodedResult = (Vec<ResultColumn>, Vec<Vec<Option<String>>>, bool);
+
+/// Decodes a streamed [`FORMAT`] body. Reads past the first `skip` rows unparsed (a later
+/// page), then keeps `max_rows` rows; later rows only set `has_more` and are read past
+/// unparsed, so a grid limit bounds memory however large the block
+/// `result_overflow_mode=break` lets the server send. A line that is not a JSON array
+/// starts the exception ClickHouse writes when a query fails mid-stream.
+struct RowReader {
+    skip: usize,
+    max_rows: usize,
+    pending: Vec<u8>,
+    names: Option<Vec<String>>,
+    types: Option<Vec<String>>,
+    rows: Vec<Vec<Option<String>>>,
+    more: bool,
+    exception: Option<String>,
+}
+
+impl RowReader {
+    fn new(skip: usize, max_rows: usize) -> Self {
+        Self {
+            skip,
+            max_rows,
+            pending: Vec::new(),
+            names: None,
+            types: None,
+            rows: Vec::new(),
+            more: false,
+            exception: None,
+        }
+    }
+
+    fn push(&mut self, chunk: &[u8]) -> IdeResult<()> {
+        self.pending.extend_from_slice(chunk);
+        let buffer = std::mem::take(&mut self.pending);
+        let mut start = 0;
+        while let Some(end) = buffer[start..].iter().position(|&b| b == b'\n') {
+            self.line(&buffer[start..start + end])?;
+            start += end + 1;
+        }
+        self.pending = buffer[start..].to_vec();
+        Ok(())
+    }
+
+    fn line(&mut self, line: &[u8]) -> IdeResult<()> {
+        if let Some(exception) = &mut self.exception {
+            if exception.len() < 16_384 {
+                exception.push_str(&String::from_utf8_lossy(line));
+                exception.push('\n');
+            }
+            return Ok(());
+        }
+        let text = line.trim_ascii();
+        if text.is_empty() {
+            return Ok(());
+        }
+        if text[0] != b'[' {
+            self.exception = Some(format!("{}\n", String::from_utf8_lossy(line)));
+            return Ok(());
+        }
+        if self.names.is_some() && self.types.is_some() {
+            if self.skip > 0 {
+                self.skip -= 1;
+                return Ok(());
+            }
+            if self.rows.len() >= self.max_rows {
+                self.more = true;
+                return Ok(());
+            }
+        }
+        let Ok(values) = serde_json::from_slice::<Vec<Box<serde_json::value::RawValue>>>(text) else {
+            self.exception = Some(format!("{}\n", String::from_utf8_lossy(line)));
+            return Ok(());
+        };
+        let protocol = |message: String| IdeError::new(ErrorKind::Protocol, message);
+        let header = |values: Vec<Box<serde_json::value::RawValue>>| {
+            values
+                .iter()
+                .map(|v| serde_json::from_str::<String>(v.get()))
+                .collect::<Result<Vec<_>, _>>()
+                .map_err(|e| protocol(format!("invalid ClickHouse result header: {e}")))
+        };
+        let Some(names) = &self.names else {
+            self.names = Some(header(values)?);
+            return Ok(());
+        };
+        if self.types.is_none() {
+            self.types = Some(header(values)?);
+            return Ok(());
+        }
+        if values.len() != names.len() {
+            return Err(protocol("ClickHouse result row width does not match its metadata".into()));
+        }
+        let row = values
+            .into_iter()
+            .map(|value| {
+                let text = value.get();
+                if text == "null" {
+                    Ok(None)
+                } else if text.starts_with('"') {
+                    serde_json::from_str::<String>(text).map(Some).map_err(|e| protocol(e.to_string()))
+                } else {
+                    Ok(Some(text.to_owned()))
+                }
+            })
+            .collect::<IdeResult<_>>()?;
+        self.rows.push(row);
+        Ok(())
+    }
+
+    fn finish(mut self) -> IdeResult<DecodedResult> {
+        let rest = std::mem::take(&mut self.pending);
+        self.line(&rest)?;
+        if let Some(exception) = self.exception {
+            return Err(IdeError::invalid(format!("ClickHouse: {}", exception_text(&exception))));
+        }
+        let Some(names) = self.names else { return Ok((Vec::new(), Vec::new(), false)) };
+        let types = self.types.unwrap_or_default();
+        if types.len() != names.len() {
+            return Err(IdeError::new(ErrorKind::Protocol, "ClickHouse result types do not match its columns"));
+        }
+        let columns = names.into_iter().zip(types).map(|(name, type_name)| ResultColumn { name, type_name }).collect();
+        Ok((columns, self.rows, self.more))
+    }
+}
+
+/// The server's message in a failed response: rows already streamed and the
+/// `__exception__` block markers ClickHouse wraps a mid-stream error in are dropped.
+fn exception_text(body: &str) -> &str {
+    let Some(at) = body.find("Code:") else { return body.trim() };
+    let text = &body[at..];
+    match text.find("\n__exception__") {
+        // The line before the closing marker is `<length> <tag>`.
+        Some(end) => text[..end].trim_end().rsplit_once('\n').map_or(text[..end].trim(), |(message, _)| message.trim()),
+        None => text.trim(),
+    }
+}
+
+fn http_error(error: reqwest::Error) -> IdeError {
+    use std::error::Error;
+    let kind = if error.is_timeout() { ErrorKind::TimedOut } else { ErrorKind::Io };
+    let error = error.without_url();
+    let mut message = error.to_string();
+    let mut source = error.source();
+    while let Some(error) = source {
+        let detail = error.to_string();
+        if !message.contains(&detail) {
+            message.push_str(": ");
+            message.push_str(&detail);
+        }
+        source = error.source();
+    }
+    IdeError::new(kind, format!("ClickHouse HTTP: {message}"))
+}
+
+fn read_pem(path: &str, label: &str) -> IdeResult<Vec<u8>> {
+    std::fs::read(ide_ssh::expand(path))
+        .map_err(|error| IdeError::new(ErrorKind::Io, format!("cannot read ClickHouse {label}: {error}")))
+}
+
+fn reserved_setting(name: &str) -> bool {
+    let name = name.to_ascii_lowercase();
+    name.starts_with("output_format_json_")
+        || matches!(
+            name.as_str(),
+            "user"
+                | "password"
+                | "query"
+                | "database"
+                | "session_id"
+                | "session_check"
+                | "session_timeout"
+                | "query_id"
+                | "default_format"
+                | "max_result_rows"
+                | "result_overflow_mode"
+                | "readonly"
+        )
+}
+
+fn transaction_statement(sql: &str) -> bool {
+    let mut sql = sql.trim_start();
+    loop {
+        if let Some(rest) = sql.strip_prefix("--").or_else(|| sql.strip_prefix('#')) {
+            sql = rest.split_once('\n').map_or("", |(_, rest)| rest).trim_start();
+        } else if let Some(rest) = sql.strip_prefix("/*") {
+            sql = rest.split_once("*/").map_or("", |(_, rest)| rest).trim_start();
+        } else {
+            break;
+        }
+    }
+    let mut words = sql.split(|c: char| !c.is_ascii_alphanumeric() && c != '_').filter(|s| !s.is_empty());
+    let first = words.next().unwrap_or_default();
+    ["BEGIN", "COMMIT", "ROLLBACK", "SAVEPOINT", "RELEASE"].iter().any(|s| first.eq_ignore_ascii_case(s))
+        || (first.eq_ignore_ascii_case("START") && words.next().is_some_and(|s| s.eq_ignore_ascii_case("TRANSACTION")))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::conn::Pool;
+    use crate::source::{DbDriver, DbOptions, DbProperty};
+    use tokio::io::{AsyncReadExt, AsyncWriteExt};
+
+    const ONE: &str = "[\"1\"]\n[\"UInt8\"]\n[1]\n";
+
+    async fn read_request(stream: &mut tokio::net::TcpStream) -> String {
+        let mut bytes = Vec::new();
+        let mut buffer = [0; 4096];
+        loop {
+            let count = tokio::time::timeout(Duration::from_secs(5), stream.read(&mut buffer)).await.unwrap().unwrap();
+            assert!(count > 0, "request ended early");
+            bytes.extend_from_slice(&buffer[..count]);
+            if let Some(end) = bytes.windows(4).position(|s| s == b"\r\n\r\n") {
+                let header = String::from_utf8_lossy(&bytes[..end]);
+                let length: usize = header
+                    .lines()
+                    .find_map(|line| {
+                        line.to_ascii_lowercase().strip_prefix("content-length:").map(|v| v.trim().parse().unwrap())
+                    })
+                    .unwrap_or(0);
+                if bytes.len() >= end + 4 + length {
+                    return String::from_utf8(bytes).unwrap();
+                }
+            }
+        }
+    }
+
+    async fn reply(stream: &mut tokio::net::TcpStream, status: &str, headers: &str, body: &str) {
+        let response =
+            format!("HTTP/1.1 {status}\r\nContent-Length: {}\r\nConnection: close\r\n{headers}\r\n{body}", body.len());
+        stream.write_all(response.as_bytes()).await.unwrap();
+    }
+
+    async fn server(
+        responses: Vec<(&'static str, &'static str, &'static str)>,
+    ) -> (u16, tokio::task::JoinHandle<Vec<String>>) {
+        let listener = tokio::net::TcpListener::bind("127.0.0.1:0").await.unwrap();
+        let port = listener.local_addr().unwrap().port();
+        let task = tokio::spawn(async move {
+            let mut requests = Vec::new();
+            for (status, headers, body) in responses {
+                let (mut stream, _) =
+                    tokio::time::timeout(Duration::from_secs(5), listener.accept()).await.unwrap().unwrap();
+                requests.push(read_request(&mut stream).await);
+                reply(&mut stream, status, headers, body).await;
+            }
+            requests
+        });
+        (port, task)
+    }
+
+    fn source(port: u16) -> DataSource {
+        DataSource { driver: DbDriver::Clickhouse, host: "127.0.0.1".into(), port: Some(port), ..Default::default() }
+    }
+
+    fn decode(body: &[u8], max_rows: usize, chunk: usize) -> IdeResult<DecodedResult> {
+        decode_from(body, 0, max_rows, chunk)
+    }
+
+    fn decode_from(body: &[u8], skip: usize, max_rows: usize, chunk: usize) -> IdeResult<DecodedResult> {
+        let mut reader = RowReader::new(skip, max_rows);
+        for part in body.chunks(chunk) {
+            reader.push(part)?;
+        }
+        reader.finish()
+    }
+
+    #[test]
+    fn rows_preserve_precision_nulls_and_strings_across_chunks() {
+        let body = concat!(
+            r#"["n", "d", "v", "v", "v"]"#,
+            "\n",
+            r#"["UInt64", "Decimal(38, 9)", "Nullable(String)", "Nullable(String)", "Nullable(String)"]"#,
+            "\n",
+            r#"[18446744073709551615, 12345678901234567890.123456789, null, "null", "ᴺᵁᴸᴸ"]"#,
+        );
+        for chunk in [1, 7, body.len()] {
+            let (columns, rows, more) = decode(body.as_bytes(), 1, chunk).unwrap();
+            assert_eq!(columns.len(), 5);
+            assert_eq!(columns[1].type_name, "Decimal(38, 9)");
+            assert_eq!(
+                rows[0],
+                vec![
+                    Some("18446744073709551615".into()),
+                    Some("12345678901234567890.123456789".into()),
+                    None,
+                    Some("null".into()),
+                    Some("ᴺᵁᴸᴸ".into()),
+                ]
+            );
+            assert!(!more);
+        }
+        let (columns, rows, more) = decode(b"[\"x\"]\n[\"String\"]\n", 0, 64).unwrap();
+        assert_eq!(columns[0].name, "x");
+        assert!(rows.is_empty() && !more);
+        assert_eq!(decode(b"", 5, 64).unwrap().0.len(), 0);
+        assert!(decode(b"[\"x\"]\n[\"UInt8\"]\n[1, 2]\n", 1, 64).is_err());
+    }
+
+    #[test]
+    fn a_later_page_skips_rows_without_keeping_them() {
+        let body = b"[\"n\"]\n[\"UInt8\"]\n[1]\n[2]\n[3]\n[4]\n[5]\n";
+        let page = |skip, max| {
+            let (_, rows, more) = decode_from(body, skip, max, 3).unwrap();
+            (rows.into_iter().map(|r| r[0].clone().unwrap()).collect::<Vec<_>>(), more)
+        };
+        assert_eq!(page(2, 2), (vec!["3".to_owned(), "4".to_owned()], true));
+        assert_eq!(page(4, 2), (vec!["5".to_owned()], false));
+        assert_eq!(page(9, 2), (Vec::<String>::new(), false));
+    }
+
+    #[test]
+    fn rows_past_the_limit_are_skipped_but_a_later_exception_still_fails() {
+        let mut body = String::from("[\"n\"]\n[\"UInt64\"]\n");
+        for n in 0..1000 {
+            body.push_str(&format!("[{n}]\n"));
+        }
+        let (_, rows, more) = decode(body.as_bytes(), 2, 4096).unwrap();
+        assert_eq!(rows, vec![vec![Some("0".into())], vec![Some("1".into())]]);
+        assert!(more);
+        body.push_str("\n__exception__\nabcdefgh\nCode: 395. DB::Exception: Value passed to 'throwIf' is non-zero\n");
+        body.push_str("62 abcdefgh\n__exception__\n");
+        let error = decode(body.as_bytes(), 2, 4096).unwrap_err();
+        assert_eq!(error.message, "ClickHouse: Code: 395. DB::Exception: Value passed to 'throwIf' is non-zero");
+        let multiline = "Code: 62. DB::Exception: Syntax error\nat line 2";
+        assert_eq!(exception_text(multiline), multiline);
+    }
+
+    #[tokio::test]
+    async fn http_requests_use_auth_settings_limits_and_a_shared_session() {
+        let (port, requests) = server(vec![
+            ("200 OK", "X-ClickHouse-Format: JSONCompactEachRowWithNamesAndTypes\r\n", ONE),
+            ("200 OK", "", ""),
+            (
+                "200 OK",
+                "X-ClickHouse-Format: JSONCompactEachRowWithNamesAndTypes\r\n",
+                "[\"n\"]\n[\"UInt64\"]\n[\"1\"]\n[\"2\"]\n[\"3\"]\n",
+            ),
+        ])
+        .await;
+        let source = DataSource {
+            user: "reader".into(),
+            read_only: true,
+            options: DbOptions { default_schema: "analytics".into(), time_zone: "UTC".into(), ..Default::default() },
+            properties: vec![DbProperty { name: "max_threads".into(), value: "2".into() }],
+            ..source(port)
+        };
+        let pool = Pool::connect(&source, Some("mock-password"), None).await.unwrap();
+        pool.execute("USE other", 0, &CancellationToken::new()).await.unwrap();
+        let result = pool.execute("SELECT number FROM numbers(3)", 1, &CancellationToken::new()).await.unwrap();
+        assert_eq!(result.rows, vec![vec![Some("1".into())]]);
+        assert!(result.has_more && result.affected.is_none());
+        let requests = requests.await.unwrap();
+        let target = |request: &String| {
+            Url::parse(&format!(
+                "http://localhost{}",
+                request.lines().next().unwrap().split_whitespace().nth(1).unwrap()
+            ))
+            .unwrap()
+        };
+        let urls: Vec<_> = requests.iter().map(target).collect();
+        let value = |url: &Url, key: &str| url.query_pairs().find(|(k, _)| k == key).map(|(_, v)| v.into_owned());
+        assert_eq!(value(&urls[0], "database").as_deref(), Some("analytics"));
+        assert_eq!(value(&urls[1], "database"), None);
+        assert_eq!(value(&urls[1], "session_check").as_deref(), Some("1"));
+        assert_eq!(value(&urls[0], "session_id"), value(&urls[2], "session_id"));
+        assert_ne!(value(&urls[0], "query_id"), value(&urls[2], "query_id"));
+        assert_eq!(value(&urls[2], "max_result_rows").as_deref(), Some("2"));
+        for (request, url) in requests.iter().zip(&urls) {
+            assert!(request.starts_with("POST /?"));
+            assert!(request.contains("Basic cmVhZGVyOm1vY2stcGFzc3dvcmQ="));
+            assert!(!url.as_str().contains("reader") && !url.as_str().contains("mock-password"));
+            assert_eq!(value(url, "readonly").as_deref(), Some("1"));
+            assert_eq!(value(url, "session_timezone").as_deref(), Some("UTC"));
+            assert_eq!(value(url, "max_threads").as_deref(), Some("2"));
+        }
+        assert!(requests[0].ends_with("SELECT 1"));
+        assert!(pool.transaction(&[]).await.is_err());
+        let cancel = CancellationToken::new();
+        cancel.cancel();
+        assert_eq!(pool.execute("SELECT 1", 1, &cancel).await.unwrap_err().kind, ErrorKind::Cancelled);
+        pool.close().await;
+        assert!(pool.is_closed());
+        assert!(pool.execute("SELECT 1", 1, &CancellationToken::new()).await.is_err());
+    }
+
+    #[tokio::test]
+    async fn sequential_queries_reuse_the_http_connection() {
+        let listener = tokio::net::TcpListener::bind("127.0.0.1:0").await.unwrap();
+        let port = listener.local_addr().unwrap().port();
+        let task = tokio::spawn(async move {
+            let (mut stream, _) = listener.accept().await.unwrap();
+            for _ in 0..2 {
+                read_request(&mut stream).await;
+                let response = format!("HTTP/1.1 200 OK\r\nContent-Length: {}\r\n\r\n{ONE}", ONE.len());
+                stream.write_all(response.as_bytes()).await.unwrap();
+            }
+        });
+        let pool = Pool::connect(&source(port), None, None).await.unwrap();
+        assert_eq!(
+            pool.execute("SELECT 1", 1, &CancellationToken::new()).await.unwrap().rows,
+            vec![vec![Some("1".into())]]
+        );
+        task.await.unwrap();
+    }
+
+    #[tokio::test]
+    async fn server_errors_keep_details_and_hide_passwords() {
+        let (port, requests) = server(vec![(
+            "403 Forbidden",
+            "X-ClickHouse-Exception-Code: 516\r\n",
+            "Code: 516. DB::Exception: bad mock-password",
+        )])
+        .await;
+        let error = match Pool::connect(&source(port), Some("mock-password"), None).await {
+            Ok(_) => panic!("expected login failure"),
+            Err(error) => error,
+        };
+        assert_eq!(error.kind, ErrorKind::PermissionDenied);
+        assert!(error.message.contains("516") && error.message.contains("[redacted]"));
+        assert!(!error.message.contains("mock-password"));
+        requests.await.unwrap();
+        let (port, requests) = server(vec![("200 OK", "", "Code: 241. DB::Exception: memory limit")]).await;
+        let error = match Pool::connect(&source(port), None, None).await {
+            Ok(_) => panic!("expected late query failure"),
+            Err(error) => error,
+        };
+        assert!(error.message.contains("memory limit"));
+        requests.await.unwrap();
+        let (port, requests) = server(vec![(
+            "500 Internal Server Error",
+            "X-ClickHouse-Exception-Code: 395\r\n",
+            "[\"1\"]\n[\"UInt8\"]\n[1]\n\n__exception__\ntag\nCode: 395. DB::Exception: thrown\n32 tag\n__exception__\n",
+        )])
+        .await;
+        let error = match Pool::connect(&source(port), None, None).await {
+            Ok(_) => panic!("expected mid-stream failure"),
+            Err(error) => error,
+        };
+        assert_eq!(error.message, "ClickHouse HTTP 500: Code: 395. DB::Exception: thrown");
+        requests.await.unwrap();
+    }
+
+    #[tokio::test]
+    async fn cancellation_sends_kill_outside_the_busy_session() {
+        let listener = tokio::net::TcpListener::bind("127.0.0.1:0").await.unwrap();
+        let port = listener.local_addr().unwrap().port();
+        let (started, received) = tokio::sync::oneshot::channel();
+        let server = tokio::spawn(async move {
+            let (mut health, _) = listener.accept().await.unwrap();
+            read_request(&mut health).await;
+            reply(&mut health, "200 OK", "", ONE).await;
+            drop(health);
+            let (mut query, _) = listener.accept().await.unwrap();
+            let request = read_request(&mut query).await;
+            started.send(()).unwrap();
+            let (mut kill, _) = tokio::time::timeout(Duration::from_secs(5), listener.accept()).await.unwrap().unwrap();
+            let kill_request = read_request(&mut kill).await;
+            reply(&mut kill, "200 OK", "", "").await;
+            (request, kill_request)
+        });
+        let pool = Pool::connect(&source(port), None, None).await.unwrap();
+        let cancel = CancellationToken::new();
+        let query = pool.execute("SELECT sleep(30)", 1, &cancel);
+        let cancelled = async {
+            received.await.unwrap();
+            cancel.cancel();
+        };
+        let (result, ()) = tokio::join!(query, cancelled);
+        assert_eq!(result.unwrap_err().kind, ErrorKind::Cancelled);
+        let (query, kill) = server.await.unwrap();
+        let target = query.lines().next().unwrap().split_whitespace().nth(1).unwrap();
+        let url = Url::parse(&format!("http://localhost{target}")).unwrap();
+        let query_id = url.query_pairs().find(|(k, _)| k == "query_id").unwrap().1.into_owned();
+        assert!(kill.ends_with(&format!("KILL QUERY WHERE query_id = '{query_id}' SYNC")));
+        assert!(!kill.contains("session_id="));
+    }
+
+    #[tokio::test]
+    async fn unsupported_settings_and_transactions_fail_before_connecting() {
+        for statement in ["BEGIN", "-- comment\n COMMIT", "/* comment */ ROLLBACK", "START TRANSACTION", "SAVEPOINT s"]
+        {
+            assert!(transaction_statement(statement));
+        }
+        assert!(!transaction_statement("SELECT 'BEGIN'"));
+        let sources = [
+            DataSource { options: DbOptions { transaction: DbTxMode::Manual, ..Default::default() }, ..source(1) },
+            DataSource {
+                properties: vec![DbProperty { name: "statement_cache_capacity".into(), value: "4".into() }],
+                ..source(1)
+            },
+            DataSource { properties: vec![DbProperty { name: "password".into(), value: "x".into() }], ..source(1) },
+            DataSource { ssl_ca_file: "unused.pem".into(), ..source(1) },
+            DataSource { ssl: DbSslMode::VerifyCa, ..source(1) },
+            DataSource { ssl: DbSslMode::Require, ssl_cert_file: "unused.pem".into(), ..source(1) },
+        ];
+        for source in sources {
+            let error = match Pool::connect(&source, None, None).await {
+                Ok(_) => panic!("unsupported settings were accepted"),
+                Err(error) => error,
+            };
+            assert_eq!(error.kind, ErrorKind::InvalidInput);
+        }
+    }
+
+    #[tokio::test]
+    #[ignore = "requires CLICKHOUSE_TEST_HOST, CLICKHOUSE_TEST_USER, and CLICKHOUSE_TEST_PASSWORD"]
+    async fn clickhouse_cloud_transport() {
+        let source = DataSource {
+            driver: DbDriver::Clickhouse,
+            host: std::env::var("CLICKHOUSE_TEST_HOST").expect("CLICKHOUSE_TEST_HOST"),
+            port: Some(std::env::var("CLICKHOUSE_TEST_PORT").ok().and_then(|v| v.parse().ok()).unwrap_or(8443)),
+            user: std::env::var("CLICKHOUSE_TEST_USER").expect("CLICKHOUSE_TEST_USER"),
+            ssl: DbSslMode::Require,
+            options: DbOptions {
+                time_zone: "UTC".into(),
+                startup_script: "SET max_threads = 2".into(),
+                ..Default::default()
+            },
+            properties: vec![DbProperty { name: "max_block_size".into(), value: "50".into() }],
+            ..Default::default()
+        };
+        let password = std::env::var("CLICKHOUSE_TEST_PASSWORD").expect("CLICKHOUSE_TEST_PASSWORD");
+        let pool = Pool::connect(&source, Some(&password), None).await.unwrap();
+        let cancel = CancellationToken::new();
+        let settings = pool
+            .execute("SELECT getSetting('max_threads'), getSetting('max_block_size'), timezone()", 1, &cancel)
+            .await
+            .unwrap();
+        assert_eq!(settings.rows, vec![vec![Some("2".into()), Some("50".into()), Some("UTC".into())]]);
+        let result = pool.execute("SELECT toUInt64('18446744073709551615') AS n, CAST(NULL AS Nullable(String)) AS missing, CAST('ᴺᵁᴸᴸ' AS Nullable(String)) AS text, 'a\\nb' AS lines", 1, &cancel).await.unwrap();
+        assert_eq!(
+            result.rows,
+            vec![vec![Some("18446744073709551615".into()), None, Some("ᴺᵁᴸᴸ".into()), Some("a\nb".into())]]
+        );
+        assert_eq!(result.columns[1].type_name, "Nullable(String)");
+        let limited = pool.execute("SELECT number FROM numbers(100)", 2, &cancel).await.unwrap();
+        assert_eq!(limited.rows.len(), 2);
+        assert!(limited.has_more);
+        let marker = format!("transport_cancel_{}", uuid::Uuid::new_v4().simple());
+        let sql = format!("SELECT sleepEachRow(0.05) FROM numbers(50) /* {marker} */");
+        let stop = CancellationToken::new();
+        let query = pool.execute(&sql, 1, &stop);
+        let cancel_query = async {
+            tokio::time::sleep(Duration::from_millis(500)).await;
+            stop.cancel();
+        };
+        let (cancelled, ()) = tokio::join!(query, cancel_query);
+        let cancelled = cancelled.unwrap_err();
+        assert_eq!(cancelled.kind, ErrorKind::Cancelled);
+        assert_eq!(cancelled.message, "cancelled");
+        let active = pool.execute(&format!("SELECT count() FROM system.processes WHERE position(query, '{marker}') > 0 AND query_id != currentQueryID()"), 1, &cancel).await.unwrap();
+        assert_eq!(active.rows, vec![vec![Some("0".into())]]);
+        let table = format!("transport_test_{}", uuid::Uuid::new_v4().simple());
+        pool.execute(&format!("CREATE TEMPORARY TABLE {table} (n UInt8)"), 0, &cancel).await.unwrap();
+        let continuity = async {
+            pool.execute(&format!("INSERT INTO {table} VALUES (7)"), 0, &cancel).await?;
+            pool.execute(&format!("SELECT n FROM {table}"), 1, &cancel).await
+        }
+        .await;
+        let cleanup = pool.execute(&format!("DROP TEMPORARY TABLE {table}"), 0, &cancel).await;
+        assert_eq!(continuity.unwrap().rows, vec![vec![Some("7".into())]]);
+        cleanup.unwrap();
+        pool.close().await;
+        assert!(pool.is_closed());
+    }
+}
@@ -106,6 +106,7 @@ pub enum Pool {
    Postgres(PgPool),
    Mysql(MySqlPool),
    SqlServer(Bb8Pool<MssqlConnectionManager>),
+    Clickhouse(crate::clickhouse::ClickhousePool),
 }

 /// Runs `$body` with `$p` bound to the concrete pool of each driver.
@@ -115,7 +116,7 @@ macro_rules! with_pool {
            Pool::Sqlite($p) => $body,
            Pool::Postgres($p) => $body,
            Pool::Mysql($p) => $body,
-            Pool::SqlServer(_) => unreachable!(),
+            Pool::SqlServer(_) | Pool::Clickhouse(_) => unreachable!(),
        }
    };
 }
@@ -336,10 +337,13 @@ fn result_columns<R: Row>(row: &R) -> Vec<ResultColumn> {
        .collect()
 }

-/// Streams the results of `$sql` on executor `$exec`, keeping at most `$max` rows
-/// with their cells read as `$mode`.
+/// Streams the results of `$sql` on executor `$exec`, reading past the first `$skip`
+/// rows without decoding them, then keeping at most `$max` rows with their cells read as `$mode`.
 macro_rules! fetch {
-    ($exec:expr, $sql:expr, $max:expr, $mode:expr) => {{
+    ($exec:expr, $sql:expr, $max:expr, $mode:expr) => {
+        fetch!($exec, $sql, 0usize, $max, $mode)
+    };
+    ($exec:expr, $sql:expr, $skip:expr, $max:expr, $mode:expr) => {{
        use futures::StreamExt;
        let mut stream = sqlx::raw_sql(sqlx::AssertSqlSafe($sql.to_owned())).fetch_many($exec);
        let mut columns: Vec<ResultColumn> = Vec::new();
@@ -348,6 +352,7 @@ macro_rules! fetch {
        let mut has_more = false;
        let mut failure = None;
        let mut first: Option<Instant> = None;
+        let mut to_skip: usize = $skip;
        while let Some(item) = stream.next().await {
            first.get_or_insert_with(Instant::now);
            match item {
@@ -356,6 +361,10 @@ macro_rules! fetch {
                    if columns.is_empty() {
                        columns = result_columns(&row);
                    }
+                    if to_skip > 0 {
+                        to_skip -= 1;
+                        continue;
+                    }
                    if rows.len() >= $max {
                        has_more = true;
                        break;
@@ -385,7 +394,8 @@ async fn mssql_command(conn: &mut MssqlClient, sql: &str) -> IdeResult<()> {
    Ok(())
 }

-async fn mssql_fetch(conn: &mut MssqlClient, sql: &str, max: usize) -> IdeResult<Fetched> {
+/// Like [`fetch!`] for SQL Server: the first `skip` rows are read past without decoding.
+async fn mssql_fetch(conn: &mut MssqlClient, sql: &str, skip: usize, max: usize) -> IdeResult<Fetched> {
    let mut stream = conn.simple_query(sql).await.map_err(mssql_err)?;
    let first = Some(Instant::now());
    let columns = stream
@@ -398,8 +408,13 @@ async fn mssql_fetch(conn: &mut MssqlClient, sql: &str, max: usize) -> IdeResult
        .collect();
    let mut rows = Vec::new();
    let mut has_more = false;
+    let mut to_skip = skip;
    while let Some(item) = stream.next().await {
        if let tiberius::QueryItem::Row(row) = item.map_err(mssql_err)? {
+            if to_skip > 0 {
+                to_skip -= 1;
+                continue;
+            }
            if rows.len() >= max {
                has_more = true;
                break;
@@ -503,6 +518,9 @@ impl Setup {
                value.parse::<u64>().map_err(|_| IdeError::invalid(format!("{what} must be a whole number: {value}")))
            };
            match (source.driver, name.to_ascii_lowercase().as_str()) {
+                (DbDriver::Clickhouse, "statement_cache_capacity") => {
+                    return Err(IdeError::invalid("ClickHouse HTTP does not support statement caching"));
+                }
                (_, "statement_cache_capacity") => s.statement_cache = Some(number(&name)? as usize),
                (_, "connect_timeout") => s.connect_timeout = Some(Duration::from_secs(number(&name)?)),
                (DbDriver::Postgres, "application_name") => s.application_name = Some(value.to_owned()),
@@ -512,6 +530,9 @@ impl Setup {
                _ => s.params.push((name, value.to_owned())),
            }
        }
+        if source.driver == DbDriver::Clickhouse && !o.time_zone.trim().is_empty() {
+            s.params.push(("session_timezone".into(), o.time_zone.trim().into()));
+        }
        let script = o.startup_script.trim();
        if !script.is_empty() {
            s.statements.extend(crate::split::split(script, source.driver).into_iter().map(|st| st.text));
@@ -527,6 +548,7 @@ impl Pool {
            Pool::Postgres(_) => DbDriver::Postgres,
            Pool::Mysql(_) => DbDriver::Mysql,
            Pool::SqlServer(_) => DbDriver::SqlServer,
+            Pool::Clickhouse(_) => DbDriver::Clickhouse,
        }
    }

@@ -534,6 +556,9 @@ impl Pool {
    pub async fn connect(source: &DataSource, password: Option<&str>, root: Option<&Path>) -> IdeResult<Self> {
        const MAX: u32 = 4;
        let setup = Setup::of(source)?;
+        if source.driver == DbDriver::Clickhouse {
+            return crate::clickhouse::ClickhousePool::connect(source, password, setup).await.map(Pool::Clickhouse);
+        }
        let timeout = setup.connect_timeout.unwrap_or(Duration::from_secs(30));
        let init = Arc::new(setup.statements);
        // Runs the session statements (startup script…) on every new connection.
@@ -695,12 +720,14 @@ impl Pool {
                conn.query("SELECT 1", &[]).await.map_err(mssql_err)?.into_results().await.map_err(mssql_err)?;
                Ok(Pool::SqlServer(pool))
            }
+            DbDriver::Clickhouse => unreachable!(),
        }
    }

    pub async fn close(&self) {
        match self {
            Pool::SqlServer(_) => {}
+            Pool::Clickhouse(p) => p.close(),
            _ => with_pool!(self, p => p.close().await),
        }
    }
@@ -708,16 +735,20 @@ impl Pool {
    pub fn is_closed(&self) -> bool {
        match self {
            Pool::SqlServer(_) => false,
+            Pool::Clickhouse(p) => p.is_closed(),
            _ => with_pool!(self, p => p.is_closed()),
        }
    }

    /// Runs `sql` (no row limit beyond `max`), for introspection: cells are text (see [`Cells::Text`]).
    pub async fn rows(&self, sql: &str, max: usize) -> IdeResult<Vec<Vec<Option<String>>>> {
+        if let Pool::Clickhouse(p) = self {
+            return Ok(p.execute(sql, max, &CancellationToken::new()).await?.rows);
+        }
        let fetched: IdeResult<Fetched> = match self {
            Pool::SqlServer(p) => {
                let mut conn = p.get_owned().await.map_err(mssql_pool_err)?;
-                mssql_fetch(&mut conn, sql, max).await
+                mssql_fetch(&mut conn, sql, 0, max).await
            }
            _ => with_pool!(self, p => fetch!(p, sql, max, Cells::Text)),
        };
@@ -727,8 +758,23 @@ impl Pool {
    /// Runs one statement and keeps at most `max_rows` rows. Cancelling stops
    /// the statement on the server (PostgreSQL, MySQL) and drops the connection.
    pub async fn execute(&self, sql: &str, max_rows: usize, cancel: &CancellationToken) -> IdeResult<QueryResult> {
+        self.execute_from(sql, 0, max_rows, cancel).await
+    }
+
+    /// [`execute`](Self::execute), reading past the first `skip` rows without keeping them
+    /// (a later page of a result: only that page is decoded and returned).
+    pub async fn execute_from(
+        &self,
+        sql: &str,
+        skip: usize,
+        max_rows: usize,
+        cancel: &CancellationToken,
+    ) -> IdeResult<QueryResult> {
+        if let Pool::Clickhouse(p) = self {
+            return p.execute_from(sql, skip, max_rows, cancel).await;
+        }
        let mut conn = Held::acquire(self).await?;
-        let r = conn.execute(self, sql, max_rows, cancel).await;
+        let r = conn.execute_from(self, sql, skip, max_rows, cancel).await;
        if cancel.is_cancelled() {
            conn.discard().await;
            return Err(IdeError::cancelled());
@@ -740,6 +786,7 @@ impl Pool {
    /// row when flagged (table editor submits).
    pub async fn transaction(&self, statements: &[(String, bool)]) -> IdeResult<u64> {
        match self {
+            Pool::Clickhouse(_) => Err(crate::clickhouse::transaction_error()),
            Pool::SqlServer(p) => {
                let mut conn = p.get_owned().await.map_err(mssql_pool_err)?;
                let result = async {
@@ -790,6 +837,7 @@ pub enum Held {
    Postgres(PoolConnection<Postgres>),
    Mysql(PoolConnection<MySql>),
    SqlServer(Box<bb8::PooledConnection<'static, MssqlConnectionManager>>),
+    Clickhouse(crate::clickhouse::ClickhousePool),
 }

 impl Held {
@@ -799,6 +847,12 @@ impl Held {
            Pool::Postgres(p) => Held::Postgres(p.acquire().await.map_err(db_err)?),
            Pool::Mysql(p) => Held::Mysql(p.acquire().await.map_err(db_err)?),
            Pool::SqlServer(p) => Held::SqlServer(Box::new(p.get_owned().await.map_err(mssql_pool_err)?)),
+            Pool::Clickhouse(p) => {
+                if p.is_closed() {
+                    return Err(IdeError::new(ErrorKind::Io, "ClickHouse connection is closed"));
+                }
+                Held::Clickhouse(p.clone())
+            }
        })
    }

@@ -806,13 +860,14 @@ impl Held {
    pub async fn command(&mut self, sql: &str) -> IdeResult<()> {
        match self {
            Held::SqlServer(c) => mssql_command(c, sql).await,
+            Held::Clickhouse(_) => Err(crate::clickhouse::transaction_error()),
            other => {
                let sql = sqlx::AssertSqlSafe(sql.to_owned());
                match other {
                    Held::Sqlite(c) => sqlx::raw_sql(sql).execute(&mut **c).await.map(drop),
                    Held::Postgres(c) => sqlx::raw_sql(sql).execute(&mut **c).await.map(drop),
                    Held::Mysql(c) => sqlx::raw_sql(sql).execute(&mut **c).await.map(drop),
-                    Held::SqlServer(_) => unreachable!(),
+                    Held::SqlServer(_) | Held::Clickhouse(_) => unreachable!(),
                }
                .map_err(db_err)
            }
@@ -833,6 +888,7 @@ impl Held {
            Held::SqlServer(mut c) => {
                c.0.take();
            }
+            Held::Clickhouse(_) => {}
        }
    }

@@ -845,6 +901,22 @@ impl Held {
        max_rows: usize,
        cancel: &CancellationToken,
    ) -> IdeResult<QueryResult> {
+        self.execute_from(pool, sql, 0, max_rows, cancel).await
+    }
+
+    /// [`execute`](Self::execute), reading past the first `skip` rows without keeping them
+    /// (see [`Pool::execute_from`]).
+    pub async fn execute_from(
+        &mut self,
+        pool: &Pool,
+        sql: &str,
+        skip: usize,
+        max_rows: usize,
+        cancel: &CancellationToken,
+    ) -> IdeResult<QueryResult> {
+        if let Held::Clickhouse(c) = self {
+            return c.execute_from(sql, skip, max_rows, cancel).await;
+        }
        let started = Instant::now();
        // `$id`: the query naming the server process, `$kill`: how another connection stops it.
        macro_rules! run {
@@ -854,7 +926,7 @@ impl Held {
                    None => None,
                };
                let r = tokio::select! {
-                    r = async { fetch!(&mut **$conn, sql, max_rows, Cells::Display) } => r,
+                    r = async { fetch!(&mut **$conn, sql, skip, max_rows, Cells::Display) } => r,
                    () = cancel.cancelled() => Err(IdeError::cancelled()),
                };
                if cancel.is_cancelled() {
@@ -883,10 +955,11 @@ impl Held {
            Held::SqlServer(c) => {
                // Tiberius has no attention/cancel API; stop reading and discard the connection.
                tokio::select! {
-                    r = mssql_fetch(c, sql, max_rows) => r?,
+                    r = mssql_fetch(c, sql, skip, max_rows) => r?,
                    () = cancel.cancelled() => return Err(IdeError::cancelled()),
                }
            }
+            Held::Clickhouse(_) => unreachable!(),
        };
        let (columns, rows, affected, has_more, first) = fetched;
        let elapsed_ms = started.elapsed().as_secs_f64() * 1000.0;
@@ -907,7 +980,7 @@ pub fn begin_statement(driver: DbDriver) -> &'static str {
    match driver {
        DbDriver::Mysql => "START TRANSACTION",
        DbDriver::SqlServer => "BEGIN TRAN",
-        DbDriver::Sqlite | DbDriver::Postgres => "BEGIN",
+        DbDriver::Sqlite | DbDriver::Postgres | DbDriver::Clickhouse => "BEGIN",
    }
 }

@@ -2,6 +2,7 @@
 //! execution ([`conn`]), introspection, table data paging / editing ([`sql`])
 //! and statement splitting ([`split`]), for SQLite, PostgreSQL and MySQL/MariaDB.

+mod clickhouse;
 pub mod conn;
 pub mod history;
 pub mod plan;
@@ -212,6 +213,8 @@ pub struct DbManager {
    /// App-wide SSH connections and host-key trust.
    ssh: Arc<SshManager>,
    saved_passwords: SecretStore,
+    /// Directory of the global data sources and their saved passwords ([`DbManager::with_global_sources`]).
+    global: Option<(PathBuf, SecretStore)>,
    history: Arc<HistoryStore>,
    /// Records executed statements in the history off the async threads, in order.
    recorder: std::sync::mpsc::Sender<(String, String, f64)>,
@@ -338,6 +341,7 @@ impl DbManager {
        }
        Self {
            saved_passwords: SecretStore::new(passwords, &root),
+            global: None,
            history,
            recorder,
            root,
@@ -350,8 +354,42 @@ impl DbManager {
        }
    }

+    /// Also lists the global data sources stored in `dir` (the app data directory).
+    pub fn with_global_sources(mut self, dir: PathBuf) -> Self {
+        let passwords = self.saved_passwords.scoped(&dir);
+        self.global = Some((dir, passwords));
+        self
+    }
+
+    /// The project's data sources, then the global ones (a project one wins on the same id).
    pub fn sources(&self) -> IdeResult<Vec<DataSource>> {
-        source::load(&self.root)
+        let mut all = source::load(&self.root)?;
+        let global: Vec<_> = self.global_sources().into_iter().filter(|g| all.iter().all(|s| s.id != g.id)).collect();
+        all.extend(global);
+        Ok(all)
+    }
+
+    fn global_sources(&self) -> Vec<DataSource> {
+        let Some((dir, _)) = &self.global else { return Vec::new() };
+        source::load_global(dir).unwrap_or_else(|e| {
+            tracing::warn!("global data sources: {}", e.message);
+            Vec::new()
+        })
+    }
+
+    /// Where the saved passwords of data source `id` live: app-wide for a global one.
+    fn saved_for(&self, id: &str) -> &SecretStore {
+        match &self.global {
+            Some((_, store)) if self.global_sources().iter().any(|s| s.id == id) => store,
+            _ => &self.saved_passwords,
+        }
+    }
+
+    fn store_of(&self, source: &DataSource) -> &SecretStore {
+        match &self.global {
+            Some((_, store)) if source.global => store,
+            _ => &self.saved_passwords,
+        }
    }

    /// The connection settings of target `target` ([`DataSource::resolved`]), with
@@ -371,18 +409,43 @@ impl DbManager {
    }

    /// Saves the data source list; connections of removed or changed sources are closed.
+    /// Global ones (`global`) go to the app-wide list, the others to the project's.
    pub async fn save_sources(&self, sources: Vec<DataSource>) -> IdeResult<()> {
        let old = self.sources().unwrap_or_default();
-        source::save(&self.root, &sources)?;
+        let (global, project): (Vec<_>, Vec<_>) = sources.iter().cloned().partition(|s| s.global);
+        match &self.global {
+            // Rewritten only when it changes: other projects' windows edit the same file.
+            Some((dir, _)) => {
+                if global != old.iter().filter(|s| s.global).cloned().collect::<Vec<_>>() {
+                    source::save_global(dir, &global)?;
+                }
+            }
+            None if !global.is_empty() => return Err(IdeError::invalid("global data sources are not available here")),
+            None => {}
+        }
+        source::save(&self.root, &project)?;
        for o in old {
            match sources.iter().find(|s| s.id == o.id) {
                Some(n) if *n == o => {}
                gone_or_changed => {
-                    if gone_or_changed.is_none() {
-                        for k in [o.id.clone(), secrets::ssh_key(&o.id)] {
-                            self.session_passwords.lock().remove(&k);
-                            self.saved_passwords.delete(&k);
+                    let keys = [o.id.clone(), secrets::ssh_key(&o.id)];
+                    match gone_or_changed {
+                        None => {
+                            for k in &keys {
+                                self.session_passwords.lock().remove(k);
+                                self.store_of(&o).delete(k);
+                            }
                        }
+                        // Made global or project-level: its saved passwords move along.
+                        Some(n) if n.global != o.global => {
+                            for k in &keys {
+                                if let Some(p) = self.store_of(&o).get(k) {
+                                    self.store_of(n).set(k, &p)?;
+                                    self.store_of(&o).delete(k);
+                                }
+                            }
+                        }
+                        Some(_) => {}
                    }
                    self.disconnect_source(&o.id).await;
                }
@@ -394,7 +457,7 @@ impl DbManager {
    /// Remembers `password` for the session, and in the saved passwords when
    /// the data source saves passwords (`None` forgets it).
    pub async fn set_password(&self, id: &str, password: Option<String>, save: bool) -> IdeResult<()> {
-        self.remember(id.to_owned(), password, save).await
+        self.remember(id, id.to_owned(), password, save).await
    }

    /// [`DbManager::set_password`] for the SSH password / key passphrase.
@@ -406,10 +469,10 @@ impl DbManager {
            self.ssh.set_secret(&c, secret, save);
            return Ok(());
        }
-        self.remember(secrets::ssh_key(id), secret, save).await
+        self.remember(id, secrets::ssh_key(id), secret, save).await
    }

-    async fn remember(&self, key: String, secret: Option<String>, save: bool) -> IdeResult<()> {
+    async fn remember(&self, id: &str, key: String, secret: Option<String>, save: bool) -> IdeResult<()> {
        match &secret {
            Some(p) => {
                self.session_passwords.lock().insert(key.clone(), p.clone());
@@ -418,10 +481,11 @@ impl DbManager {
                self.session_passwords.lock().remove(&key);
            }
        }
+        let store = self.saved_for(id);
        let result = match (secret, save) {
-            (Some(p), true) => self.saved_passwords.set(&key, &p),
+            (Some(p), true) => store.set(&key, &p),
            _ => {
-                self.saved_passwords.delete(&key);
+                store.delete(&key);
                Ok(())
            }
        };
@@ -432,18 +496,18 @@ impl DbManager {
        Ok(())
    }

-    async fn secret(&self, key: String, saved: bool) -> Option<String> {
+    async fn secret(&self, source: &DataSource, key: String, saved: bool) -> Option<String> {
        if let Some(p) = self.session_passwords.lock().get(&key) {
            return Some(p.clone());
        }
        if !saved {
            return None;
        }
-        self.saved_passwords.get(&key)
+        self.store_of(source).get(&key)
    }

    async fn password(&self, source: &DataSource) -> Option<String> {
-        match self.secret(source.id.clone(), source.driver != DbDriver::Sqlite && source.save_password).await {
+        match self.secret(source, source.id.clone(), source.driver != DbDriver::Sqlite && source.save_password).await {
            Some(p) => Some(p),
            None => source.url_password(),
        }
@@ -499,7 +563,7 @@ impl DbManager {
        let session = if config.is_empty() {
            let secret = match ssh_secret {
                Some(s) => Some(s),
-                None => self.secret(secrets::ssh_key(&source.id), ssh.save_secret).await,
+                None => self.secret(source, secrets::ssh_key(&source.id), ssh.save_secret).await,
            };
            let target = SshTarget {
                host: ssh.host.clone(),
@@ -547,12 +611,14 @@ impl DbManager {
        })?;
        let version = match source.driver {
            DbDriver::Sqlite => "SELECT 'SQLite ' || sqlite_version()",
-            DbDriver::Postgres => "SELECT version()",
+            DbDriver::Postgres | DbDriver::Clickhouse => "SELECT version()",
            DbDriver::Mysql => "SELECT CONCAT(@@version_comment, ' ', VERSION())",
            DbDriver::SqlServer => "SELECT @@VERSION",
        };
-        let v = pool.rows(version, 1).await.ok().and_then(|r| r.into_iter().next()?.into_iter().next()?);
+        let result = pool.rows(version, 1).await;
        pool.close().await;
+        let rows = if source.driver == DbDriver::Clickhouse { result? } else { result.unwrap_or_default() };
+        let v = rows.into_iter().next().and_then(|r| r.into_iter().next().flatten());
        Ok(v.unwrap_or_else(|| "Connected".into()))
    }

@@ -701,8 +767,11 @@ impl DbManager {
                _ => indexes.push(IndexInfo { name, unique: flag(&unique), columns: vec![col] }),
            }
        }
-        let fk_rows =
-            pool.rows(&sql::table_foreign_keys(driver, schema, table), MAX_META_ROWS).await.unwrap_or_default();
+        let fk_rows = if driver == DbDriver::Clickhouse {
+            Vec::new()
+        } else {
+            pool.rows(&sql::table_foreign_keys(driver, schema, table), MAX_META_ROWS).await.unwrap_or_default()
+        };
        let mut foreign_keys = group_foreign_keys(fk_rows, &[]);
        // SQLite keys that reference the primary key implicitly: look it up.
        for k in foreign_keys.iter_mut().filter(|k| k.ref_columns.is_empty()) {
@@ -715,13 +784,15 @@ impl DbManager {
                .collect();
        }
        foreign_keys.retain(|k| k.columns.len() == k.ref_columns.len());
-        let triggers = pool
-            .rows(&sql::triggers(driver, schema, table), MAX_META_ROWS)
-            .await
-            .unwrap_or_else(|e| {
+        let trigger_rows = if driver == DbDriver::Clickhouse {
+            Vec::new()
+        } else {
+            pool.rows(&sql::triggers(driver, schema, table), MAX_META_ROWS).await.unwrap_or_else(|e| {
                tracing::warn!("triggers: {}", e.message);
                Vec::new()
            })
+        };
+        let triggers = trigger_rows
            .into_iter()
            .filter_map(|r| {
                let mut it = r.into_iter();
@@ -822,6 +893,11 @@ impl DbManager {
                let ddl = cells(pool.rows(&q, 1).await?, 1).into_iter().next();
                ddl.map(|d| format!("{d};\n")).ok_or_else(missing)
            }
+            DbDriver::Clickhouse => {
+                let q = format!("SHOW CREATE TABLE {}", sql::qualified(driver, schema, name));
+                let ddl = cells(pool.rows(&q, 1).await?, 0).into_iter().next();
+                ddl.map(|d| format!("{};\n", d.trim_end().trim_end_matches(';'))).ok_or_else(missing)
+            }
            DbDriver::SqlServer => {
                let obj = format!("{}.{}", schema, name).replace('\'', "''");
                let ddl = cells(pool.rows(&format!("SELECT OBJECT_DEFINITION(OBJECT_ID('{}'))", obj), 1).await?, 0)
@@ -902,10 +978,14 @@ impl DbManager {
            }
        }
        // Foreign keys are a nicety (JOIN completion): a server that refuses the catalog query still completes.
-        let fk_rows = pool.rows(sql::foreign_keys(driver), MAX_META_ROWS).await.unwrap_or_else(|e| {
-            tracing::warn!("foreign keys: {}", e.message);
+        let fk_rows = if driver == DbDriver::Clickhouse {
            Vec::new()
-        });
+        } else {
+            pool.rows(sql::foreign_keys(driver), MAX_META_ROWS).await.unwrap_or_else(|e| {
+                tracing::warn!("foreign keys: {}", e.message);
+                Vec::new()
+            })
+        };
        let foreign_keys = group_foreign_keys(fk_rows, &tables);
        let default_schema = match sql::current_schema(driver) {
            None => "main".to_owned(),
@@ -929,7 +1009,20 @@ impl DbManager {
        max_rows: usize,
        cancel: &CancellationToken,
    ) -> IdeResult<QueryResult> {
-        let r = self.run(id, statement, max_rows, cancel).await;
+        self.execute_from(id, statement, 0, max_rows, cancel).await
+    }
+
+    /// [`execute`](Self::execute), reading past the first `skip` rows without keeping
+    /// them: a later page of a result, where only that page is decoded and returned.
+    pub async fn execute_from(
+        &self,
+        id: &str,
+        statement: &str,
+        skip: usize,
+        max_rows: usize,
+        cancel: &CancellationToken,
+    ) -> IdeResult<QueryResult> {
+        let r = self.run(id, statement, skip, max_rows, cancel).await;
        let ran = match &r {
            Ok(_) => true,
            Err(e) => !matches!(e.kind, ErrorKind::Cancelled | ErrorKind::PermissionDenied),
@@ -964,7 +1057,7 @@ impl DbManager {
    /// The execution plan of `statement` (explained, not run).
    pub async fn explain(&self, id: &str, statement: &str, cancel: &CancellationToken) -> IdeResult<Vec<PlanNode>> {
        let driver = self.pool(id).await?.driver();
-        let result = self.run(id, &plan::explain_statement(driver, statement), MAX_META_ROWS, cancel).await?;
+        let result = self.run(id, &plan::explain_statement(driver, statement), 0, MAX_META_ROWS, cancel).await?;
        plan::parse(driver, &result)
    }

@@ -972,14 +1065,18 @@ impl DbManager {
        &self,
        id: &str,
        statement: &str,
+        skip: usize,
        max_rows: usize,
        cancel: &CancellationToken,
    ) -> IdeResult<QueryResult> {
        let pool = self.pool(id).await?;
        let session = self.sessions.lock().get(id).cloned();
        let Some(session) = session else {
-            return pool.execute(statement, max_rows, cancel).await;
+            return pool.execute_from(statement, skip, max_rows, cancel).await;
        };
+        if pool.driver() == DbDriver::Clickhouse {
+            return Err(IdeError::invalid("ClickHouse manual transactions are unsupported"));
+        }
        let mut held = session.lock().await;
        if held.is_none() {
            let mut conn = Held::acquire(&pool).await?;
@@ -987,7 +1084,7 @@ impl DbManager {
            *held = Some(conn);
        }
        let conn = held.as_mut().expect("opened above");
-        let r = conn.execute(&pool, statement, max_rows, cancel).await;
+        let r = conn.execute_from(&pool, statement, skip, max_rows, cancel).await;
        if cancel.is_cancelled() {
            // The server rolls the transaction back with the connection.
            held.take().expect("opened above").discard().await;
@@ -998,8 +1095,11 @@ impl DbManager {

    /// Switches `id` between auto-commit and manual commit. Leaving manual
    /// mode rolls back what was not committed.
-    pub async fn set_manual_commit(&self, id: &str, manual: bool) {
+    pub async fn set_manual_commit(&self, id: &str, manual: bool) -> IdeResult<()> {
        if manual {
+            if self.source(id)?.driver == DbDriver::Clickhouse {
+                return Err(IdeError::invalid("ClickHouse manual transactions are unsupported"));
+            }
            self.sessions.lock().entry(id.to_owned()).or_default();
        } else {
            let session = self.sessions.lock().remove(id);
@@ -1007,10 +1107,14 @@ impl DbManager {
                end_session(&s).await;
            }
        }
+        Ok(())
    }

    /// Commits (or rolls back) the open transaction of a manual-commit data source.
    pub async fn finish_transaction(&self, id: &str, commit: bool) -> IdeResult<()> {
+        if self.source(id).is_ok_and(|s| s.driver == DbDriver::Clickhouse) {
+            return Err(IdeError::invalid("ClickHouse manual transactions are unsupported"));
+        }
        let session = self.sessions.lock().get(id).cloned();
        let Some(session) = session else { return Ok(()) };
        let mut held = session.lock().await;
@@ -1052,6 +1156,9 @@ impl DbManager {

    /// Applies the table editor's pending changes in one transaction.
    pub async fn apply_edits(&self, id: &str, schema: &str, table: &str, edits: &[DbRowEdit]) -> IdeResult<u64> {
+        if self.source(id)?.driver == DbDriver::Clickhouse {
+            return Err(IdeError::invalid("ClickHouse table editing is unsupported"));
+        }
        let pool = self.pool(id).await?;
        let driver = pool.driver();
        let statements = edits
@@ -1064,3 +1171,112 @@ impl DbManager {
        pool.transaction(&statements).await
    }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use ide_ssh::secrets::testing::files_containing;
+    use std::path::Path;
+
+    fn manager(dir: &Path) -> DbManager {
+        ide_ssh::secrets::testing::use_memory_store();
+        let data = dir.join("data");
+        let ssh = Arc::new(SshManager::new(data.join("ssh-passwords.json")));
+        DbManager::new(dir.join("project"), data.join("db-passwords.json"), data.join("db-history.json"), ssh)
+    }
+
+    #[tokio::test]
+    async fn saved_passwords_stay_off_disk() {
+        let tmp = tempfile::tempdir().unwrap();
+        manager(tmp.path()).set_password("s1", Some("hunter2-db".into()), true).await.unwrap();
+        manager(tmp.path()).set_ssh_secret("s1", Some("hunter2-tunnel".into()), true).await.unwrap();
+        assert_eq!(files_containing(tmp.path(), "hunter2-db"), Vec::<PathBuf>::new());
+        assert_eq!(files_containing(tmp.path(), "hunter2-tunnel"), Vec::<PathBuf>::new());
+        let reopened = manager(tmp.path());
+        assert_eq!(reopened.secret(&DataSource::default(), "s1".into(), true).await.as_deref(), Some("hunter2-db"));
+        assert_eq!(
+            reopened.secret(&DataSource::default(), secrets::ssh_key("s1"), true).await.as_deref(),
+            Some("hunter2-tunnel")
+        );
+    }
+
+    #[tokio::test]
+    async fn moves_plaintext_passwords_of_older_versions_off_disk() {
+        let tmp = tempfile::tempdir().unwrap();
+        let project = tmp.path().join("project").to_string_lossy().into_owned();
+        let legacy = serde_json::json!({ project: { "s1": "old-db-pw" }, "/other": { "s2": "other-pw" } });
+        std::fs::create_dir_all(tmp.path().join("data")).unwrap();
+        std::fs::write(tmp.path().join("data/db-passwords.json"), legacy.to_string()).unwrap();
+        let m = manager(tmp.path());
+        assert_eq!(m.secret(&DataSource::default(), "s1".into(), true).await.as_deref(), Some("old-db-pw"));
+        assert_eq!(files_containing(tmp.path(), "old-db-pw"), Vec::<PathBuf>::new());
+        assert_eq!(files_containing(tmp.path(), "other-pw"), Vec::<PathBuf>::new());
+        let other = SecretStore::new(tmp.path().join("data/db-passwords.json"), Path::new("/other"));
+        assert_eq!(other.get("s2").as_deref(), Some("other-pw"));
+    }
+
+    #[tokio::test]
+    async fn global_data_sources_are_shared_by_projects_with_their_passwords() {
+        ide_ssh::secrets::testing::use_memory_store();
+        let tmp = tempfile::tempdir().unwrap();
+        let (app, one, two) = (tmp.path().join("app"), tmp.path().join("one"), tmp.path().join("two"));
+        let manager = |root: &std::path::Path| {
+            let ssh = Arc::new(SshManager::new(app.join("ssh-passwords.json")));
+            DbManager::new(root.to_path_buf(), app.join("passwords.json"), app.join("history.json"), ssh)
+                .with_global_sources(app.clone())
+        };
+        let (a, b) = (manager(&one), manager(&two));
+        let source = |id: &str, global: bool| DataSource {
+            id: id.into(),
+            name: id.into(),
+            driver: DbDriver::Postgres,
+            save_password: true,
+            global,
+            ..Default::default()
+        };
+        a.save_sources(vec![source("local", false), source("shared", false)]).await.unwrap();
+        a.set_password("shared", Some("pw".into()), true).await.unwrap();
+        // Made global: listed in the other project too, with its saved password.
+        a.save_sources(vec![source("local", false), source("shared", true)]).await.unwrap();
+        let ids = |m: &DbManager| m.sources().unwrap().into_iter().map(|s| (s.id, s.global)).collect::<Vec<_>>();
+        assert_eq!(ids(&a), [("local".into(), false), ("shared".into(), true)]);
+        assert_eq!(ids(&b), [("shared".into(), true)]);
+        assert_eq!(b.password(&b.source("shared").unwrap()).await.as_deref(), Some("pw"));
+        let project_file = std::fs::read_to_string(one.join(".openidea/data-sources.toml")).unwrap();
+        assert!(!project_file.contains("shared") && !project_file.contains("global"), "{project_file}");
+        assert!(!std::fs::read_to_string(app.join("data-sources.toml")).unwrap().contains("global"));
+        // Made project-level again: gone from the other project, the password stays with it.
+        a.save_sources(vec![source("local", false), source("shared", false)]).await.unwrap();
+        assert!(b.sources().unwrap().is_empty());
+        assert_eq!(a.password(&a.source("shared").unwrap()).await.as_deref(), Some("pw"));
+    }
+
+    #[tokio::test]
+    async fn clickhouse_rejects_manual_transactions_and_table_edits_without_connecting() {
+        let tmp = tempfile::tempdir().unwrap();
+        let root = tmp.path().to_path_buf();
+        let ssh = Arc::new(SshManager::new(root.join("ssh-passwords.json")));
+        let db = DbManager::new(root.clone(), root.join("passwords.json"), root.join("history.json"), ssh);
+        db.save_sources(vec![DataSource {
+            id: "clickhouse".into(),
+            name: "clickhouse".into(),
+            driver: DbDriver::Clickhouse,
+            host: "127.0.0.1".into(),
+            port: Some(1),
+            ..Default::default()
+        }])
+        .await
+        .unwrap();
+        let error = db.set_manual_commit("clickhouse", true).await.unwrap_err();
+        assert!(error.message.contains("manual transactions are unsupported"));
+        assert!(db.sessions.lock().is_empty());
+        for commit in [false, true] {
+            let error = db.finish_transaction("clickhouse", commit).await.unwrap_err();
+            assert!(error.message.contains("manual transactions are unsupported"));
+        }
+        let error = db.apply_edits("clickhouse", "default", "events", &[]).await.unwrap_err();
+        assert!(error.message.contains("table editing is unsupported"));
+        assert!(!db.is_connected("clickhouse"));
+        db.set_manual_commit("clickhouse", false).await.unwrap();
+    }
+}
@@ -35,6 +35,7 @@ pub fn explain_statement(driver: DbDriver, statement: &str) -> String {
    match driver {
        DbDriver::Sqlite => format!("EXPLAIN QUERY PLAN {s}"),
        DbDriver::Postgres => format!("EXPLAIN (FORMAT JSON) {s}"),
+        DbDriver::Clickhouse => format!("EXPLAIN json = 1 {s}"),
        DbDriver::Mysql => format!("EXPLAIN {s}"),
        DbDriver::SqlServer => format!("SET SHOWPLAN_TEXT ON; {s}"),
    }
@@ -44,7 +45,7 @@ pub fn explain_statement(driver: DbDriver, statement: &str) -> String {
 pub fn parse(driver: DbDriver, result: &QueryResult) -> IdeResult<Vec<PlanNode>> {
    match driver {
        DbDriver::Sqlite => Ok(sqlite(&result.rows)),
-        DbDriver::Postgres => {
+        DbDriver::Postgres | DbDriver::Clickhouse => {
            let text: String =
                result.rows.iter().filter_map(|r| r.first().cloned().flatten()).collect::<Vec<_>>().join("\n");
            let json: Value = serde_json::from_str(&text).map_err(|e| IdeError::invalid(format!("plan: {e}")))?;
@@ -199,6 +200,7 @@ mod tests {
        assert_eq!(explain_statement(DbDriver::Sqlite, "select 1;"), "EXPLAIN QUERY PLAN select 1");
        assert_eq!(explain_statement(DbDriver::Postgres, " select 1 "), "EXPLAIN (FORMAT JSON) select 1");
        assert_eq!(explain_statement(DbDriver::Mysql, "select 1"), "EXPLAIN select 1");
+        assert_eq!(explain_statement(DbDriver::Clickhouse, " select 1;"), "EXPLAIN json = 1 select 1");
        assert_eq!(explain_statement(DbDriver::SqlServer, "select 1"), "SET SHOWPLAN_TEXT ON; select 1");
    }

@@ -254,6 +256,21 @@ mod tests {
        assert_eq!((plan[3].parent, plan[3].operation.as_str()), (Some(2), "Seq Scan"));
    }

+    #[test]
+    fn reads_clickhouse_json_plans_and_rejects_invalid_json() {
+        let json = r#"[{"Plan": {"Node Type": "Expression", "Node Id": "Expression_5",
+            "Description": "Project names", "Plans": [
+                {"Node Type": "ReadFromMergeTree", "Node Id": "ReadFromMergeTree_0",
+                 "Description": "default.events"}
+            ]}}]"#;
+        let plan = parse(DbDriver::Clickhouse, &result(&["explain"], vec![vec![Some(json)]])).unwrap();
+        assert_eq!(plan.len(), 2);
+        assert_eq!((plan[0].parent, plan[0].operation.as_str()), (None, "Expression"));
+        assert_eq!((plan[1].parent, plan[1].operation.as_str()), (Some(0), "ReadFromMergeTree"));
+        assert!(plan[1].properties.iter().any(|p| p.name == "Description" && p.value == "default.events"));
+        assert!(parse(DbDriver::Clickhouse, &result(&["explain"], vec![vec![Some("invalid")]])).is_err());
+    }
+
    #[test]
    fn reads_mysql_rows() {
        let r = result(
@@ -1,20 +1,15 @@
-//! Saved data source passwords, in the app's data directory rather than the OS
-//! credential store (no system prompts). One JSON file for all projects, keyed
-//! by project root, then credential key; owner-only on Unix.
+//! Saved data source passwords, in the OS credential store like the other saved
+//! passwords ([`SecretFile`]). One index file for all projects; each credential is
+//! keyed by project root, then credential key.

-use ide_core::{IdeError, IdeResult};
-use parking_lot::Mutex;
+use ide_core::IdeResult;
+use ide_ssh::secrets::SecretFile;
 use std::collections::BTreeMap;
 use std::path::{Path, PathBuf};

-/// Project root → credential key → secret.
-type Contents = BTreeMap<String, BTreeMap<String, String>>;
-
-/// Serialises read-modify-write across the projects sharing the file.
-static LOCK: Mutex<()> = Mutex::new(());
-
 pub struct SecretStore {
    path: PathBuf,
+    file: SecretFile,
    project: String,
 }

@@ -23,61 +18,41 @@ pub fn ssh_key(id: &str) -> String {
    format!("{id}#ssh")
 }

+fn file_key(project: &str, key: &str) -> String {
+    format!("{project}|{key}")
+}
+
+/// Older versions' file: project root → credential key → secret.
+fn legacy(value: serde_json::Value) -> Option<BTreeMap<String, String>> {
+    let all: BTreeMap<String, BTreeMap<String, String>> = serde_json::from_value(value).ok()?;
+    Some(
+        all.into_iter()
+            .flat_map(|(project, keys)| keys.into_iter().map(move |(k, s)| (file_key(&project, &k), s)))
+            .collect(),
+    )
+}
+
 impl SecretStore {
    pub fn new(path: PathBuf, root: &Path) -> Self {
-        Self { path, project: root.to_string_lossy().into_owned() }
+        let file = SecretFile::with_legacy(path.clone(), legacy);
+        Self { path, file, project: root.to_string_lossy().into_owned() }
+    }
+
+    /// The same file, keyed by `scope` instead (global data sources: the app data directory).
+    pub fn scoped(&self, scope: &Path) -> Self {
+        Self::new(self.path.clone(), scope)
    }

    pub fn get(&self, key: &str) -> Option<String> {
-        let _g = LOCK.lock();
-        self.read().remove(&self.project)?.remove(key)
+        self.file.get(&file_key(&self.project, key))
    }

    pub fn set(&self, key: &str, secret: &str) -> IdeResult<()> {
-        let _g = LOCK.lock();
-        let mut all = self.read();
-        all.entry(self.project.clone()).or_default().insert(key.to_owned(), secret.to_owned());
-        self.write(&all)
+        self.file.set(&file_key(&self.project, key), secret)
    }

    pub fn delete(&self, key: &str) {
-        let _g = LOCK.lock();
-        let mut all = self.read();
-        let Some(project) = all.get_mut(&self.project) else { return };
-        if project.remove(key).is_none() {
-            return;
-        }
-        if project.is_empty() {
-            all.remove(&self.project);
-        }
-        if let Err(e) = self.write(&all) {
-            tracing::warn!("saved passwords: {}", e.message);
-        }
-    }
-
-    fn read(&self) -> Contents {
-        match std::fs::read(&self.path) {
-            Ok(bytes) => serde_json::from_slice(&bytes).unwrap_or_else(|e| {
-                tracing::warn!("saved passwords: {}: {e}", self.path.display());
-                Contents::new()
-            }),
-            Err(_) => Contents::new(),
-        }
-    }
-
-    fn write(&self, all: &Contents) -> IdeResult<()> {
-        let err = |e: std::io::Error| IdeError::unavailable(format!("saved passwords: {e}"));
-        if let Some(dir) = self.path.parent() {
-            std::fs::create_dir_all(dir).map_err(err)?;
-        }
-        let tmp = self.path.with_extension("json.tmp");
-        let mut options = std::fs::OpenOptions::new();
-        options.write(true).create(true).truncate(true);
-        #[cfg(unix)]
-        std::os::unix::fs::OpenOptionsExt::mode(&mut options, 0o600);
-        let bytes = serde_json::to_vec_pretty(all).map_err(|e| IdeError::internal(e.to_string()))?;
-        std::io::Write::write_all(&mut options.open(&tmp).map_err(err)?, &bytes).map_err(err)?;
-        std::fs::rename(&tmp, &self.path).map_err(err)
+        self.file.delete(&file_key(&self.project, key))
    }
 }

@@ -87,6 +62,7 @@ mod tests {

    #[test]
    fn keeps_projects_apart_and_drops_empty_ones() {
+        ide_ssh::secrets::testing::use_memory_store();
        let tmp = tempfile::tempdir().unwrap();
        let file = tmp.path().join("db-passwords.json");
        let a = SecretStore::new(file.clone(), Path::new("/p/a"));
@@ -1,6 +1,7 @@
-//! Data sources: per-project connection settings in `.openidea/data-sources.toml`.
-//! Passwords never go there: saved ones live in [`crate::secrets`], the others
-//! only in memory for the session.
+//! Data sources: per-project connection settings in `.openidea/data-sources.toml`, and
+//! global ones (IDEA's Make Global: listed in every project) in `data-sources.toml` of the
+//! app data directory. Passwords never go there: saved ones live in [`crate::secrets`],
+//! the others only in memory for the session.

 use ide_core::{IdeError, IdeResult, IpcPath, project_dir};
 use serde::{Deserialize, Serialize};
@@ -18,6 +19,7 @@ pub enum DbDriver {
    Mysql,
    /// Microsoft SQL Server.
    SqlServer,
+    Clickhouse,
 }

 impl DbDriver {
@@ -27,6 +29,7 @@ impl DbDriver {
            DbDriver::Postgres => Some(5432),
            DbDriver::Mysql => Some(3306),
            DbDriver::SqlServer => Some(1433),
+            DbDriver::Clickhouse => Some(8123),
        }
    }
 }
@@ -179,6 +182,9 @@ pub struct DataSource {
    pub options: DbOptions,
    pub introspection: DbIntrospection,
    pub properties: Vec<DbProperty>,
+    /// Stored app-wide and listed in every project. Implied by the file it is read from,
+    /// so not written to it.
+    pub global: bool,
 }

 impl Default for DataSource {
@@ -207,6 +213,7 @@ impl Default for DataSource {
            options: DbOptions::default(),
            introspection: DbIntrospection::default(),
            properties: Vec::new(),
+            global: false,
        }
    }
 }
@@ -253,6 +260,7 @@ pub fn scheme_driver(scheme: &str) -> Option<DbDriver> {
        "mysql" | "mariadb" | "tidb" | "singlestore" | "memsql" | "oceanbase" => Some(DbDriver::Mysql),
        "sqlserver" | "mssql" | "mssqlserver" => Some(DbDriver::SqlServer),
        "sqlite" | "sqlite3" => Some(DbDriver::Sqlite),
+        "clickhouse" | "http" | "https" => Some(DbDriver::Clickhouse),
        _ => None,
    }
 }
@@ -260,7 +268,7 @@ pub fn scheme_driver(scheme: &str) -> Option<DbDriver> {
 /// Parses `scheme://[user[:password]@]host[:port][/database][?k=v&…]`, `jdbc:` forms
 /// included, and `sqlite:path`.
 pub fn parse_url(raw: &str) -> IdeResult<ParsedUrl> {
-    let bad = || IdeError::invalid(format!("not a database URL: {raw}"));
+    let bad = || IdeError::invalid("invalid database URL");
    let url = raw.trim();
    let url = url.strip_prefix("jdbc:").or_else(|| url.strip_prefix("JDBC:")).unwrap_or(url);
    let (scheme, rest) = url.split_once(':').ok_or_else(bad)?;
@@ -367,6 +375,15 @@ impl DataSource {
        }
        properties.append(&mut s.properties);
        s.properties = properties;
+        if s.driver == DbDriver::Clickhouse {
+            let raw_url = self.url.trim().to_ascii_lowercase();
+            let url = raw_url.strip_prefix("jdbc:").unwrap_or(&raw_url);
+            if url.starts_with("https://") {
+                s.ssl = DbSslMode::VerifyFull;
+            } else if url.starts_with("http://") {
+                s.ssl = DbSslMode::Disable;
+            }
+        }
        Ok(s)
    }

@@ -385,9 +402,32 @@ struct SourcesFile {
    sources: Vec<DataSource>,
 }

+/// The project's data sources.
 pub fn load(root: &Path) -> IdeResult<Vec<DataSource>> {
-    let path = project_dir::path(root, FILE);
-    let text = match std::fs::read_to_string(&path) {
+    read(&project_dir::path(root, FILE))
+}
+
+/// Saves the project's data sources.
+pub fn save(root: &Path, sources: &[DataSource]) -> IdeResult<()> {
+    write(&project_dir::path(root, FILE), sources)
+}
+
+/// The global data sources stored in `dir` (the app data directory).
+pub fn load_global(dir: &Path) -> IdeResult<Vec<DataSource>> {
+    let mut sources = read(&dir.join(FILE))?;
+    for s in &mut sources {
+        s.global = true;
+    }
+    Ok(sources)
+}
+
+/// Saves the global data sources in `dir`.
+pub fn save_global(dir: &Path, sources: &[DataSource]) -> IdeResult<()> {
+    write(&dir.join(FILE), sources)
+}
+
+fn read(path: &Path) -> IdeResult<Vec<DataSource>> {
+    let text = match std::fs::read_to_string(path) {
        Ok(t) => t,
        Err(e) if e.kind() == std::io::ErrorKind::NotFound => return Ok(Vec::new()),
        Err(e) => return Err(e.into()),
@@ -396,19 +436,23 @@ pub fn load(root: &Path) -> IdeResult<Vec<DataSource>> {
    Ok(file.sources)
 }

-pub fn save(root: &Path, sources: &[DataSource]) -> IdeResult<()> {
+fn write(path: &Path, sources: &[DataSource]) -> IdeResult<()> {
    for s in sources {
        if s.id.is_empty() || s.name.trim().is_empty() {
            return Err(IdeError::invalid("every data source needs an id and a name"));
        }
    }
-    let path = project_dir::path(root, FILE);
    if let Some(dir) = path.parent() {
        std::fs::create_dir_all(dir)?;
    }
-    let text = toml::to_string_pretty(&SourcesFile { sources: sources.to_vec() })
-        .map_err(|e| IdeError::internal(e.to_string()))?;
-    std::fs::write(path, text)?;
+    let internal = |e: &dyn std::fmt::Display| IdeError::internal(e.to_string());
+    let mut value = toml::Value::try_from(SourcesFile { sources: sources.to_vec() }).map_err(|e| internal(&e))?;
+    if let Some(list) = value.get_mut("data-source").and_then(toml::Value::as_array_mut) {
+        for table in list.iter_mut().filter_map(toml::Value::as_table_mut) {
+            table.remove("global");
+        }
+    }
+    std::fs::write(path, toml::to_string_pretty(&value).map_err(|e| internal(&e))?)?;
    Ok(())
 }

@@ -519,4 +563,31 @@ mod tests {
        assert!(DataSource { url: "mysql://h/db".into(), ..s.clone() }.resolved().is_err());
        assert_eq!(DataSource { url_only: false, ..s }.resolved().unwrap().host, "localhost");
    }
+
+    #[test]
+    fn clickhouse_urls_resolve_http_https_and_credentials() {
+        assert_eq!(DbDriver::Clickhouse.default_port(), Some(8123));
+        let source = DataSource {
+            driver: DbDriver::Clickhouse,
+            url_only: true,
+            url: "https://reader:s%[email protected]:8443/analytics?max_execution_time=30".into(),
+            ..Default::default()
+        };
+        let resolved = source.resolved().unwrap();
+        assert_eq!(resolved.host, "db.example");
+        assert_eq!(resolved.port, Some(8443));
+        assert_eq!(resolved.database, "analytics");
+        assert_eq!(resolved.user, "reader");
+        assert_eq!(resolved.ssl, DbSslMode::VerifyFull);
+        assert_eq!(source.url_password().as_deref(), Some("s@cret"));
+        assert_eq!(resolved.properties[0].name, "max_execution_time");
+        let http = DataSource { url: "http://localhost/default".into(), ..source.clone() }.resolved().unwrap();
+        assert_eq!(http.ssl, DbSslMode::Disable);
+        let jdbc = DataSource { url: "jdbc:clickhouse://localhost/analytics".into(), ..source.clone() };
+        assert_eq!(jdbc.resolved().unwrap().database, "analytics");
+        let secure = DataSource { url: "https://db.example/default?sslmode=disable".into(), ..source };
+        assert_eq!(secure.resolved().unwrap().ssl, DbSslMode::VerifyFull);
+        let error = parse_url("clickhouse://reader:[email protected]:invalid/default").unwrap_err();
+        assert!(!error.message.contains("secret"));
+    }
 }
@@ -28,6 +28,7 @@ enum State {
 /// Every statement of `text` that contains more than whitespace and comments.
 pub fn split(text: &str, driver: DbDriver) -> Vec<SqlStatement> {
    let mysql = driver == DbDriver::Mysql;
+    let clickhouse = driver == DbDriver::Clickhouse;
    let chars: Vec<(usize, char)> = text.char_indices().collect();
    // UTF-16 offset of each char index (plus the end).
    let mut u16_at = Vec::with_capacity(chars.len() + 1);
@@ -81,7 +82,7 @@ pub fn split(text: &str, driver: DbDriver) -> Vec<SqlStatement> {
                    state = State::Double;
                    has_code = true;
                }
-                '`' if mysql => {
+                '`' if mysql || clickhouse => {
                    state = State::Backtick;
                    has_code = true;
                }
@@ -117,7 +118,7 @@ pub fn split(text: &str, driver: DbDriver) -> Vec<SqlStatement> {
                _ => {}
            },
            State::Single => {
-                if mysql && c == '\\' {
+                if (mysql || clickhouse) && c == '\\' {
                    i += 1;
                } else if c == '\'' {
                    if next == Some('\'') {
@@ -128,7 +129,9 @@ pub fn split(text: &str, driver: DbDriver) -> Vec<SqlStatement> {
                }
            }
            State::Double => {
-                if c == '"' {
+                if clickhouse && c == '\\' {
+                    i += 1;
+                } else if c == '"' {
                    if next == Some('"') {
                        i += 1;
                    } else {
@@ -137,7 +140,9 @@ pub fn split(text: &str, driver: DbDriver) -> Vec<SqlStatement> {
                }
            }
            State::Backtick => {
-                if c == '`' {
+                if clickhouse && (c == '\\' || (c == '`' && next == Some('`'))) {
+                    i += 1;
+                } else if c == '`' {
                    state = State::Code;
                }
            }
@@ -224,6 +229,12 @@ mod tests {
        assert_eq!(texts(sql, DbDriver::Mysql), vec!["select `a;b`, 'it\\'s;' from t # x;y", "select 2"]);
    }

+    #[test]
+    fn clickhouse_backticks_and_escaped_quotes_keep_statements_intact() {
+        let query = r#"SELECT `a\`;b`, "c\";d", 'it\'s;safe'; SELECT 2"#;
+        assert_eq!(texts(query, DbDriver::Clickhouse), vec![r#"SELECT `a\`;b`, "c\";d", 'it\'s;safe'"#, "SELECT 2"]);
+    }
+
    #[test]
    fn postgres_dollar_quotes() {
        let sql =
@@ -7,6 +7,7 @@ use specta::Type;

 pub fn quote_ident(driver: DbDriver, name: &str) -> String {
    match driver {
+        DbDriver::Clickhouse => format!("`{}`", name.replace('\\', "\\\\").replace('`', "\\`")),
        DbDriver::Mysql => format!("`{}`", name.replace('`', "``")),
        DbDriver::SqlServer => format!("[{}]", name.replace(']', "]]")),
        _ => format!("\"{}\"", name.replace('"', "\"\"")),
@@ -15,7 +16,7 @@ pub fn quote_ident(driver: DbDriver, name: &str) -> String {

 pub fn quote_literal(driver: DbDriver, value: &str) -> String {
    let mut s = value.replace('\'', "''");
-    if driver == DbDriver::Mysql {
+    if matches!(driver, DbDriver::Mysql | DbDriver::Clickhouse) {
        s = s.replace('\\', "\\\\");
    }
    format!("'{s}'")
@@ -48,6 +49,10 @@ pub const INTERNAL_DATABASES: &[&str] = &["rdsadmin", "azure_maintenance", "azur
 pub fn schemas(driver: DbDriver, system: bool) -> &'static str {
    match driver {
        DbDriver::Sqlite => "SELECT name FROM pragma_database_list WHERE name <> 'temp' ORDER BY seq",
+        DbDriver::Clickhouse if system => "SELECT name FROM system.databases ORDER BY name",
+        DbDriver::Clickhouse => {
+            "SELECT name FROM system.databases WHERE lower(name) NOT IN ('system', 'information_schema') ORDER BY name"
+        }
        DbDriver::Postgres if system => {
            "SELECT schema_name FROM information_schema.schemata \
             WHERE schema_name NOT LIKE 'pg\\_toast%' AND schema_name NOT LIKE 'pg\\_temp%' ORDER BY 1"
@@ -73,6 +78,12 @@ pub fn schemas(driver: DbDriver, system: bool) -> &'static str {
 /// Rows: `name, kind` where kind is `table`, `view` or `materialized view`.
 pub fn tables(driver: DbDriver, schema: &str) -> String {
    match driver {
+        DbDriver::Clickhouse => format!(
+            "SELECT name, CASE engine WHEN 'View' THEN 'view' WHEN 'MaterializedView' THEN 'materialized view' \
+             WHEN 'WindowView' THEN 'view' ELSE 'table' END FROM system.tables \
+             WHERE database = {} AND is_temporary = 0 ORDER BY name",
+            quote_literal(driver, schema)
+        ),
        DbDriver::Sqlite => format!(
            "SELECT name, type FROM {}.sqlite_master WHERE type IN ('table', 'view') \
             AND name NOT LIKE 'sqlite\\_%' ESCAPE '\\' ORDER BY name",
@@ -101,6 +112,12 @@ pub fn tables(driver: DbDriver, schema: &str) -> String {
 pub fn columns(driver: DbDriver, schema: &str, table: &str) -> String {
    let (s, t) = (quote_literal(driver, schema), quote_literal(driver, table));
    match driver {
+        DbDriver::Clickhouse => format!(
+            "SELECT name, type, CASE WHEN startsWith(type, 'Nullable(') \
+             OR startsWith(type, 'LowCardinality(Nullable(') THEN 'YES' ELSE 'NO' END, \
+             if(default_kind = '', NULL, default_expression), is_in_primary_key \
+             FROM system.columns WHERE database = {s} AND table = {t} ORDER BY position"
+        ),
        DbDriver::Sqlite => format!(
            "SELECT name, type, CASE WHEN \"notnull\" = 0 THEN 'YES' ELSE 'NO' END, dflt_value, \
             CASE WHEN pk > 0 THEN 1 ELSE 0 END FROM pragma_table_info({t}, {s}) ORDER BY cid"
@@ -138,6 +155,12 @@ pub fn columns(driver: DbDriver, schema: &str, table: &str) -> String {
 pub fn indexes(driver: DbDriver, schema: &str, table: &str) -> String {
    let (s, t) = (quote_literal(driver, schema), quote_literal(driver, table));
    match driver {
+        DbDriver::Clickhouse => format!(
+            "SELECT * FROM (SELECT 'PRIMARY KEY' AS index_name, 0 AS is_unique, primary_key AS expression \
+             FROM system.tables WHERE database = {s} AND name = {t} AND primary_key != '' \
+             UNION ALL SELECT name, 0, expr FROM system.data_skipping_indices \
+             WHERE database = {s} AND table = {t}) ORDER BY index_name"
+        ),
        DbDriver::Sqlite => format!(
            "SELECT il.name, il.\"unique\", ii.name FROM pragma_index_list({t}, {s}) il \
             JOIN pragma_index_info(il.name, {s}) ii ORDER BY il.name, ii.seqno"
@@ -169,6 +192,15 @@ pub fn indexes(driver: DbDriver, schema: &str, table: &str) -> String {
 /// for SQL completion, grouped by table in column order.
 pub fn completion_columns(driver: DbDriver) -> &'static str {
    match driver {
+        DbDriver::Clickhouse => {
+            "SELECT c.database, c.table, CASE t.engine WHEN 'View' THEN 'view' \
+             WHEN 'MaterializedView' THEN 'materialized view' WHEN 'WindowView' THEN 'view' ELSE 'table' END, \
+             c.name, c.type, CASE WHEN startsWith(c.type, 'Nullable(') \
+             OR startsWith(c.type, 'LowCardinality(Nullable(') THEN 'YES' ELSE 'NO' END, c.is_in_primary_key, 1 \
+             FROM system.columns c JOIN system.tables t ON t.database = c.database AND t.name = c.table \
+             WHERE lower(c.database) NOT IN ('system', 'information_schema') AND t.is_temporary = 0 \
+             ORDER BY c.database, c.table, c.position LIMIT 50000"
+        }
        DbDriver::Sqlite => {
            "SELECT 'main', m.name, m.type, p.name, p.type, CASE WHEN p.\"notnull\" = 0 THEN 'YES' ELSE 'NO' END, \
             CASE WHEN p.pk > 0 THEN 1 ELSE 0 END, \
@@ -221,6 +253,7 @@ pub fn completion_columns(driver: DbDriver) -> &'static str {
 /// when the key references the primary key implicitly.
 pub fn foreign_keys(driver: DbDriver) -> &'static str {
    match driver {
+        DbDriver::Clickhouse => "SELECT '', '', '', '', '', '', '' WHERE 0",
        DbDriver::Sqlite => {
            "SELECT 'main', m.name, f.id, f.\"from\", 'main', f.\"table\", f.\"to\" \
             FROM sqlite_master m JOIN pragma_foreign_key_list(m.name) f \
@@ -258,6 +291,7 @@ pub fn foreign_keys(driver: DbDriver) -> &'static str {
 pub fn table_foreign_keys(driver: DbDriver, schema: &str, table: &str) -> String {
    let (s, t) = (quote_literal(driver, schema), quote_literal(driver, table));
    match driver {
+        DbDriver::Clickhouse => foreign_keys(driver).to_owned(),
        DbDriver::Sqlite => format!(
            "SELECT {s}, {t}, f.id, f.\"from\", {s}, f.\"table\", f.\"to\"              FROM pragma_foreign_key_list({t}, {s}) f ORDER BY f.id, f.seq"
        ),
@@ -276,6 +310,7 @@ pub fn table_foreign_keys(driver: DbDriver, schema: &str, table: &str) -> String
 /// The schema unqualified names resolve to (`None`: always `main`).
 pub fn current_schema(driver: DbDriver) -> Option<&'static str> {
    match driver {
+        DbDriver::Clickhouse => Some("SELECT currentDatabase()"),
        DbDriver::Sqlite => None,
        DbDriver::Postgres => Some("SELECT current_schema()"),
        DbDriver::Mysql => Some("SELECT DATABASE()"),
@@ -362,6 +397,9 @@ fn where_key(driver: DbDriver, key: &[CellValue]) -> String {
 /// The DML statement for `edit`. Values are written as quoted literals, which
 /// every supported database coerces to the column type.
 pub fn edit_statement(driver: DbDriver, schema: &str, table: &str, edit: &DbRowEdit) -> Result<String, String> {
+    if driver == DbDriver::Clickhouse {
+        return Err("ClickHouse table editing is unsupported: primary keys do not uniquely identify rows and edits require transactions".into());
+    }
    let target = qualified(driver, schema, table);
    match edit {
        DbRowEdit::Update { key, values } => {
@@ -450,6 +488,7 @@ pub fn postgres_ddl_indexes(oid: u32) -> String {
 pub fn triggers(driver: DbDriver, schema: &str, table: &str) -> String {
    let (s, t) = (quote_literal(driver, schema), quote_literal(driver, table));
    match driver {
+        DbDriver::Clickhouse => "SELECT '', '', '' WHERE 0".to_owned(),
        DbDriver::Sqlite => format!(
            "SELECT name, sql FROM {}.sqlite_master WHERE type = 'trigger' AND tbl_name = {t} ORDER BY name",
            quote_ident(driver, schema)
@@ -492,7 +531,7 @@ pub fn sqlite_trigger_event(sql: &str) -> (String, String) {
 pub fn routines(driver: DbDriver, schema: &str) -> Option<String> {
    let s = quote_literal(driver, schema);
    match driver {
-        DbDriver::Sqlite => None,
+        DbDriver::Sqlite | DbDriver::Clickhouse => None,
        // Functions of extensions are left out, as in IDEA.
        DbDriver::Postgres => Some(format!(
            "SELECT p.proname, CASE WHEN p.prokind = 'p' THEN 'procedure' ELSE 'function' END, \
@@ -625,6 +664,71 @@ mod tests {
        assert_eq!(quote_literal(DbDriver::Mysql, "it's \\"), "'it''s \\\\'");
    }

+    #[test]
+    fn clickhouse_escapes_backslashes_and_delimiters() {
+        let driver = DbDriver::Clickhouse;
+        assert_eq!(quote_literal(driver, r"path\O'Brien"), r"'path\\O''Brien'");
+        assert_eq!(quote_literal(driver, r"\' OR 1 = 1 --"), r"'\\'' OR 1 = 1 --'");
+        assert_eq!(quote_ident(driver, r"a\`b"), r"`a\\\`b`");
+        assert_eq!(qualified(driver, "data base", "event`log"), r"`data base`.`event\`log`");
+    }
+
+    #[test]
+    fn clickhouse_metadata_preserves_types_defaults_and_nonunique_keys() {
+        let driver = DbDriver::Clickhouse;
+        assert_eq!(schemas(driver, true), "SELECT name FROM system.databases ORDER BY name");
+        assert!(schemas(driver, false).contains("lower(name) NOT IN ('system', 'information_schema')"));
+        assert_eq!(current_schema(driver), Some("SELECT currentDatabase()"));
+        let relations = tables(driver, "event's\\db");
+        assert!(relations.contains("WHEN 'MaterializedView' THEN 'materialized view'"));
+        assert!(relations.contains(r"WHERE database = 'event''s\\db' AND is_temporary = 0"));
+        let fields = columns(driver, "default", "events");
+        assert!(fields.starts_with("SELECT name, type, CASE WHEN startsWith(type, 'Nullable(')"));
+        assert!(fields.contains("startsWith(type, 'LowCardinality(Nullable(')"));
+        assert!(fields.contains("if(default_kind = '', NULL, default_expression), is_in_primary_key"));
+        assert!(fields.ends_with("WHERE database = 'default' AND table = 'events' ORDER BY position"));
+        let keys = indexes(driver, "default", "events");
+        assert!(keys.contains("'PRIMARY KEY' AS index_name, 0 AS is_unique, primary_key AS expression"));
+        assert!(keys.contains("SELECT name, 0, expr FROM system.data_skipping_indices"));
+        let completion = completion_columns(driver);
+        assert!(completion.contains("c.is_in_primary_key, 1"));
+        assert!(completion.contains("ORDER BY c.database, c.table, c.position LIMIT 50000"));
+    }
+
+    #[test]
+    fn clickhouse_has_no_foreign_key_trigger_or_schema_routine_catalogs() {
+        let driver = DbDriver::Clickhouse;
+        assert_eq!(foreign_keys(driver), "SELECT '', '', '', '', '', '', '' WHERE 0");
+        assert_eq!(table_foreign_keys(driver, "default", "events"), foreign_keys(driver));
+        assert_eq!(triggers(driver, "default", "events"), "SELECT '', '', '' WHERE 0");
+        assert!(routines(driver, "default").is_none());
+        assert!(sequences(driver, "default").is_none());
+        assert!(object_ddl(driver, "default", crate::DbObjectKind::Trigger, "t").is_none());
+    }
+
+    #[test]
+    fn clickhouse_pages_quote_keys_and_fetch_one_extra_row() {
+        let sort = [SortKey { column: "event`id".into(), descending: true }];
+        assert_eq!(
+            table_page(DbDriver::Clickhouse, "default", "events", Some("WHERE id > 3"), &sort, 50, 25),
+            r"SELECT * FROM `default`.`events` WHERE id > 3 ORDER BY `event\`id` DESC LIMIT 26 OFFSET 50"
+        );
+    }
+
+    #[test]
+    fn clickhouse_keys_never_enable_transactional_table_edits() {
+        let key = vec![cv("id", Some("1"))];
+        for edit in [
+            DbRowEdit::Update { key: key.clone(), values: vec![cv("name", Some("new"))] },
+            DbRowEdit::Delete { key },
+            DbRowEdit::Insert { values: vec![cv("name", Some("new"))] },
+            DbRowEdit::Insert { values: vec![] },
+        ] {
+            let error = edit_statement(DbDriver::Clickhouse, "default", "events", &edit).unwrap_err();
+            assert!(error.contains("primary keys do not uniquely identify rows"));
+        }
+    }
+
    #[test]
    fn pages() {
        let sort = [SortKey { column: "id".into(), descending: true }];
@@ -0,0 +1,136 @@
+use ide_core::{CancellationToken, IdeError, IdeResult};
+use ide_db::{CellValue, DataSource, DbDriver, DbManager, DbRowEdit, DbSslMode, SortKey, sql};
+use std::sync::Arc;
+use std::time::{SystemTime, UNIX_EPOCH};
+
+fn check(condition: bool, message: &str) -> IdeResult<()> {
+    if condition { Ok(()) } else { Err(IdeError::invalid(message)) }
+}
+
+#[tokio::test]
+#[ignore = "requires CLICKHOUSE_TEST_HOST, CLICKHOUSE_TEST_USER, and CLICKHOUSE_TEST_PASSWORD"]
+async fn clickhouse_cloud_manager_catalogs_and_session_table() -> IdeResult<()> {
+    let tmp = tempfile::tempdir()?;
+    let root = tmp.path().to_path_buf();
+    let ssh = Arc::new(ide_ssh::SshManager::new(root.join("ssh-passwords.json")));
+    let db = DbManager::new(root.clone(), root.join("passwords.json"), root.join("history.json"), ssh);
+    let mut source = DataSource {
+        id: "clickhouse".into(),
+        name: "clickhouse".into(),
+        driver: DbDriver::Clickhouse,
+        host: std::env::var("CLICKHOUSE_TEST_HOST").expect("set CLICKHOUSE_TEST_HOST"),
+        port: Some(
+            std::env::var("CLICKHOUSE_TEST_PORT")
+                .map(|value| value.parse().expect("numeric CLICKHOUSE_TEST_PORT"))
+                .unwrap_or(8443),
+        ),
+        user: std::env::var("CLICKHOUSE_TEST_USER").expect("set CLICKHOUSE_TEST_USER"),
+        database: "default".into(),
+        ssl: DbSslMode::VerifyFull,
+        ..Default::default()
+    };
+    source.introspection.show_system = true;
+    let password = std::env::var("CLICKHOUSE_TEST_PASSWORD").expect("set CLICKHOUSE_TEST_PASSWORD");
+    check(!db.test(&source, Some(password.clone()), None).await?.is_empty(), "missing server version")?;
+    db.save_sources(vec![source]).await?;
+    db.set_password("clickhouse", Some(password), false).await?;
+    let cancel = CancellationToken::new();
+    let suffix = SystemTime::now().duration_since(UNIX_EPOCH).unwrap().as_nanos();
+    let name = format!("manager_test_{}_{suffix}", std::process::id());
+    let table = sql::quote_ident(DbDriver::Clickhouse, &name);
+    db.execute(
+        "clickhouse",
+        &format!(
+            "CREATE TEMPORARY TABLE {table} (id UInt64, label Nullable(String) DEFAULT NULL, \
+             category LowCardinality(Nullable(String)) DEFAULT NULL, items Array(Nullable(UInt8)), \
+             label_size UInt64 ALIAS length(ifNull(label, ''))) ENGINE = Memory"
+        ),
+        0,
+        &cancel,
+    )
+    .await?;
+    let checked: IdeResult<()> = async {
+        db.execute(
+            "clickhouse",
+            &format!("INSERT INTO {table} (id, label, items) VALUES (1, 'first', [1, NULL]), (1, NULL, [])"),
+            0,
+            &cancel,
+        )
+        .await?;
+        let schemas = db.schemas("clickhouse").await?;
+        check(schemas.iter().any(|schema| schema == "default"), "default database missing")?;
+        check(schemas.iter().any(|schema| schema == "system"), "system database missing")?;
+        let tables = db.tables("clickhouse", "system").await?;
+        check(tables.iter().any(|table| table.name == "one"), "system table listing missing one")?;
+        let details = db.table_details("clickhouse", "", &name).await?;
+        check(details.columns.len() == 5, "temporary table columns missing")?;
+        for (name, data_type, nullable) in [
+            ("id", "UInt64", false),
+            ("label", "Nullable(String)", true),
+            ("category", "LowCardinality(Nullable(String))", true),
+            ("items", "Array(Nullable(UInt8))", false),
+        ] {
+            check(
+                details
+                    .columns
+                    .iter()
+                    .any(|column| column.name == name && column.data_type == data_type && column.nullable == nullable),
+                "column type or nullability mismatch",
+            )?;
+        }
+        check(
+            details.columns.iter().any(|column| column.name == "label" && column.default.as_deref() == Some("NULL")),
+            "explicit default expression missing",
+        )?;
+        check(details.indexes.iter().all(|index| !index.unique), "ClickHouse index reported unique")?;
+        check(details.foreign_keys.is_empty() && details.triggers.is_empty(), "unsupported table objects returned")?;
+        let sort = [SortKey { column: "id".into(), descending: false }];
+        let first = db.table_page("clickhouse", "", &name, None, &sort, 0, 1, &cancel).await?;
+        check(first.result.rows.len() == 1 && first.result.has_more, "first page limit failed")?;
+        let second = db.table_page("clickhouse", "", &name, None, &sort, 1, 1, &cancel).await?;
+        check(second.result.rows.len() == 1 && !second.result.has_more, "page offset failed")?;
+        let ddl = db.ddl("clickhouse", "", &name).await?;
+        check(ddl.contains(&name) && ddl.contains("Memory"), "temporary table DDL missing")?;
+        let completion = db.completion("clickhouse").await?;
+        check(completion.default_schema == "default", "completion default database mismatch")?;
+        check(completion.foreign_keys.is_empty(), "completion returned unsupported foreign keys")?;
+        if let Some(table) = completion.tables.first() {
+            let details = db.table_details("clickhouse", &table.schema, &table.name).await?;
+            check(
+                table.columns.iter().all(|column| {
+                    details.columns.iter().any(|field| field.name == column.name && field.data_type == column.data_type)
+                }),
+                "completion columns differ from catalog",
+            )?;
+        }
+        let plan = db.explain("clickhouse", &format!("SELECT id FROM {table}"), &cancel).await?;
+        check(!plan.is_empty(), "query plan missing")?;
+        let value = r"path\O'Brien";
+        let result = db
+            .execute("clickhouse", &format!("SELECT {}", sql::quote_literal(DbDriver::Clickhouse, value)), 1, &cancel)
+            .await?;
+        check(result.rows == vec![vec![Some(value.to_owned())]], "quoted literal changed value")?;
+        let edits = [DbRowEdit::Update {
+            key: vec![CellValue { column: "id".into(), value: Some("1".into()) }],
+            values: vec![CellValue { column: "label".into(), value: Some("changed".into()) }],
+        }];
+        check(
+            db.apply_edits("clickhouse", "", &name, &edits)
+                .await
+                .err()
+                .is_some_and(|error| error.message.contains("table editing is unsupported")),
+            "supplied row key authorized table editing",
+        )?;
+        check(db.set_manual_commit("clickhouse", true).await.is_err(), "manual transactions were accepted")?;
+        for commit in [false, true] {
+            check(db.finish_transaction("clickhouse", commit).await.is_err(), "transaction control was accepted")?;
+        }
+        Ok(())
+    }
+    .await;
+    let cleanup = db.execute("clickhouse", &format!("DROP TEMPORARY TABLE {table}"), 0, &cancel).await;
+    db.disconnect("clickhouse").await;
+    checked?;
+    cleanup?;
+    Ok(())
+}
@@ -1,7 +1,9 @@
 //! Introspection, queries and table edits against a real SQLite file.

 use ide_core::{CancellationToken, IdeResult};
-use ide_db::{CellValue, DataSource, DbDriver, DbManager, DbOptions, DbProperty, DbRowEdit, DbTableKind, SortKey};
+use ide_db::{
+    CellValue, DataSource, DbDriver, DbManager, DbOptions, DbProperty, DbRowEdit, DbTableKind, QueryResult, SortKey,
+};

 async fn setup() -> (tempfile::TempDir, DbManager) {
    let tmp = tempfile::tempdir().unwrap();
@@ -123,6 +125,28 @@ async fn queries_with_limits_nulls_and_blobs() -> IdeResult<()> {
    Ok(())
 }

+#[tokio::test]
+async fn a_later_page_returns_only_its_rows() -> IdeResult<()> {
+    let (_tmp, db) = setup().await;
+    let c = CancellationToken::new();
+    let sql = "SELECT id FROM users ORDER BY id";
+    let ids = |r: &QueryResult| r.rows.iter().map(|row| row[0].clone().unwrap()).collect::<Vec<_>>();
+
+    let second = db.execute_from("s1", sql, 1, 1, &c).await?;
+    assert_eq!(ids(&second), vec!["2"]);
+    assert!(second.has_more);
+    assert_eq!(second.columns.len(), 1);
+
+    let last = db.execute_from("s1", sql, 2, 5, &c).await?;
+    assert_eq!(ids(&last), vec!["3"]);
+    assert!(!last.has_more);
+
+    let past = db.execute_from("s1", sql, 9, 5, &c).await?;
+    assert!(past.rows.is_empty() && !past.has_more);
+    assert_eq!(past.columns.len(), 1, "columns of a page past the end come from the prepared statement");
+    Ok(())
+}
+
 #[tokio::test]
 async fn pages_sorts_filters_and_edits_in_a_transaction() -> IdeResult<()> {
    let (_tmp, db) = setup().await;
@@ -197,7 +221,7 @@ async fn count(db: &DbManager) -> String {
 async fn manual_commit_keeps_a_transaction_until_commit_or_rollback() -> IdeResult<()> {
    let (_tmp, db) = setup().await;
    let c = CancellationToken::new();
-    db.set_manual_commit("s1", true).await;
+    db.set_manual_commit("s1", true).await.unwrap();
    db.execute("s1", "INSERT INTO users (name) VALUES ('dee')", 1, &c).await?;
    // The session sees its own change.
    assert_eq!(count(&db).await, "4");
@@ -208,10 +232,10 @@ async fn manual_commit_keeps_a_transaction_until_commit_or_rollback() -> IdeResu
    db.finish_transaction("s1", true).await?;
    // Leaving manual mode rolls back what is still open.
    db.execute("s1", "DELETE FROM users", 1, &c).await?;
-    db.set_manual_commit("s1", false).await;
+    db.set_manual_commit("s1", false).await.unwrap();
    assert_eq!(count(&db).await, "4");
    // Disconnecting with an open transaction does not hang.
-    db.set_manual_commit("s1", true).await;
+    db.set_manual_commit("s1", true).await.unwrap();
    db.execute("s1", "DELETE FROM users", 1, &c).await?;
    db.disconnect("s1").await;
    assert_eq!(count(&db).await, "4");
@@ -13,8 +13,5 @@ specta.workspace = true
 tracing.workspace = true
 which = "8"

-[target.'cfg(unix)'.dependencies]
-libc = "0.2"
-
 [dev-dependencies]
 tempfile.workspace = true
@@ -1,11 +1,16 @@
 //! Child processes of the docker CLI: bounded runs and cancellable line streams.

+use ide_core::process::terminate_tree;
 use ide_core::{CancellationToken, IdeError, IdeResult};
 use std::io::Read;
 use std::process::{Child, Command, Stdio};
 use std::sync::mpsc;
 use std::time::{Duration, Instant};

+/// How long a cancelled or timed-out child's process group (CLI plugins such as compose)
+/// gets to exit on `SIGTERM`, and clean up, before `SIGKILL`.
+const KILL_GRACE: Duration = Duration::from_millis(20);
+
 pub(crate) struct Output {
    pub stdout: String,
    pub stderr: String,
@@ -20,36 +25,13 @@ pub(crate) enum Stream {

 fn prepare(cmd: &mut Command) {
    cmd.stdin(Stdio::null()).stdout(Stdio::piped()).stderr(Stdio::piped());
-    #[cfg(unix)]
-    {
-        use std::os::unix::process::CommandExt;
-        cmd.process_group(0);
-    }
-    ide_core::process::prepare(cmd);
+    ide_core::process::prepare(ide_core::process::own_group(cmd));
 }

 fn spawn(cmd: &mut Command) -> IdeResult<Child> {
    cmd.spawn().map_err(|e| IdeError::unavailable(format!("could not run docker: {e}")))
 }

-/// Kills the child and, on Unix, its whole process group (CLI plugins such as compose).
-pub(crate) fn kill(child: &mut Child) {
-    #[cfg(unix)]
-    {
-        let pid = child.id() as libc::pid_t;
-        // SAFETY: plain syscall; the child leads its own process group (`prepare`).
-        unsafe {
-            libc::kill(-pid, libc::SIGTERM);
-        }
-        std::thread::sleep(Duration::from_millis(20));
-        unsafe {
-            libc::kill(-pid, libc::SIGKILL);
-        }
-    }
-    let _ = child.kill();
-    let _ = child.wait();
-}
-
 fn read_all(mut pipe: impl Read + Send + 'static) -> std::thread::JoinHandle<String> {
    std::thread::spawn(move || {
        let mut buf = Vec::new();
@@ -88,11 +70,11 @@ pub(crate) fn run_with_input(
            break status;
        }
        if cancel.is_some_and(CancellationToken::is_cancelled) {
-            kill(&mut child);
+            terminate_tree(&mut child, KILL_GRACE);
            return Err(IdeError::cancelled());
        }
        if Instant::now() >= deadline {
-            kill(&mut child);
+            terminate_tree(&mut child, KILL_GRACE);
            return Err(IdeError::unavailable("docker did not respond in time"));
        }
        std::thread::sleep(Duration::from_millis(10));
@@ -166,7 +148,7 @@ pub(crate) fn stream(
    let mut stderr_tail: Vec<String> = Vec::new();
    while open > 0 {
        if cancel.is_cancelled() {
-            kill(&mut child);
+            terminate_tree(&mut child, KILL_GRACE);
            return Err(IdeError::cancelled());
        }
        match rx.recv_timeout(Duration::from_millis(50)) {
@@ -189,7 +171,7 @@ pub(crate) fn stream(
            break status;
        }
        if cancel.is_cancelled() {
-            kill(&mut child);
+            terminate_tree(&mut child, KILL_GRACE);
            return Err(IdeError::cancelled());
        }
        std::thread::sleep(Duration::from_millis(10));
@@ -0,0 +1,24 @@
+[package]
+name = "ide-extension"
+description = "Plugin manifest, extension points, contribution registry and capability model (no Wasm runtime)"
+version.workspace = true
+edition.workspace = true
+license.workspace = true
+
+[dependencies]
+ide-core.workspace = true
+serde.workspace = true
+serde_json.workspace = true
+specta.workspace = true
+specta-typescript.workspace = true
+toml.workspace = true
+tracing.workspace = true
+parking_lot.workspace = true
+semver = "1"
+blake3.workspace = true
+zip.workspace = true
+base64.workspace = true
+ed25519-dalek = "3"
+
+[dev-dependencies]
+tempfile.workspace = true
@@ -0,0 +1,279 @@
+//! What a plugin may do beyond pure computation, and how risky each grant is.
+//!
+//! Capabilities are written as strings in the manifest (`project.read`,
+//! `net:crates.io`, `process:cargo`) and stored the same way in the grant
+//! ledger. The 0.1 permission names (`project-read`, …) parse as their 0.2
+//! equivalents.
+
+use serde::{Deserialize, Deserializer, Serialize, Serializer};
+use specta::Type;
+use std::fmt;
+use std::str::FromStr;
+
+#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub enum Capability {
+    /// Read files inside the project root; the project root itself.
+    ProjectRead,
+    /// The focused editor's file, selection and text.
+    EditorRead,
+    /// Edit the focused editor (versioned edits).
+    EditorWrite,
+    VcsRead,
+    VcsWrite,
+    /// The plugin's own key-value store and data directory.
+    Storage,
+    /// The plugin's own secrets (kept in the client's OS keychain).
+    Secrets,
+    /// Workbench events (file opened, saved, focus…), not keystrokes.
+    Events,
+    /// Keystrokes and editor input events.
+    InputEvents,
+    /// The system clipboard, from the plugin's web views.
+    Clipboard,
+    /// HTTP(S) to one host (`*.example.com` matches subdomains).
+    Net(String),
+    /// Run one external program. Full code execution: never fine-grained.
+    Process(String),
+    /// Read files outside the project under one path.
+    FsRead(String),
+}
+
+/// How a grant is presented (plan 4.2).
+#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize, Type)]
+#[serde(rename_all = "camelCase")]
+pub enum Risk {
+    /// Listed on the install page, one confirmation.
+    Low,
+    /// Listed separately with its purpose.
+    Medium,
+    /// Separate dialog: "equivalent to running arbitrary code on this machine".
+    High,
+}
+
+impl Capability {
+    pub fn risk(&self) -> Risk {
+        match self {
+            Self::ProjectRead | Self::EditorRead | Self::Storage | Self::Events | Self::VcsRead => Risk::Low,
+            Self::EditorWrite | Self::VcsWrite | Self::Net(_) | Self::Secrets | Self::InputEvents | Self::Clipboard => {
+                Risk::Medium
+            }
+            Self::Process(_) | Self::FsRead(_) => Risk::High,
+        }
+    }
+
+    /// Low-risk capabilities that the one-time migration of the 0.1 "declared
+    /// means granted" behaviour may grant automatically (plan 4.6).
+    pub fn auto_migrates(&self) -> bool {
+        self.risk() == Risk::Low
+    }
+
+    /// Short user-facing description for install and grant pages.
+    pub fn describe(&self) -> String {
+        match self {
+            Self::ProjectRead => "Read files in the open project".into(),
+            Self::EditorRead => "Read the focused editor's file and selection".into(),
+            Self::EditorWrite => "Change text in the editor".into(),
+            Self::VcsRead => "Read version control state".into(),
+            Self::VcsWrite => "Change version control state (commit, fetch, checkout)".into(),
+            Self::Storage => "Store its own data".into(),
+            Self::Secrets => "Store secrets in the system keychain".into(),
+            Self::Events => "Observe workbench events (files opened, saved, focus)".into(),
+            Self::InputEvents => "Observe keystrokes and editor input".into(),
+            Self::Clipboard => {
+                "Copy to the clipboard from its commands, and read and write it from its web views".into()
+            }
+            Self::Net(host) => format!("Connect to {host} (from the machine the project is on)"),
+            Self::Process(bin) => format!("Run {bin} — equivalent to running arbitrary code on this machine"),
+            Self::FsRead(path) => format!("Read files under {path}, outside the project"),
+        }
+    }
+
+    /// Whether `self`, granted, also covers `wanted` (`net:*.x.com` covers `net:a.x.com`).
+    pub fn covers(&self, wanted: &Capability) -> bool {
+        match (self, wanted) {
+            (Self::Net(pattern), Self::Net(host)) => host_matches(pattern, host),
+            (Self::FsRead(base), Self::FsRead(path)) => {
+                std::path::Path::new(path).starts_with(std::path::Path::new(base))
+            }
+            _ => self == wanted,
+        }
+    }
+}
+
+/// `example.com` matches exactly; `*.example.com` matches any subdomain (not the apex).
+pub fn host_matches(pattern: &str, host: &str) -> bool {
+    let host = host.trim_end_matches('.').to_ascii_lowercase();
+    let pattern = pattern.to_ascii_lowercase();
+    match pattern.strip_prefix("*.") {
+        Some(suffix) => host.len() > suffix.len() + 1 && host.ends_with(&format!(".{suffix}")),
+        None => host == pattern,
+    }
+}
+
+impl fmt::Display for Capability {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Self::ProjectRead => f.write_str("project.read"),
+            Self::EditorRead => f.write_str("editor.read"),
+            Self::EditorWrite => f.write_str("editor.write"),
+            Self::VcsRead => f.write_str("vcs.read"),
+            Self::VcsWrite => f.write_str("vcs.write"),
+            Self::Storage => f.write_str("storage"),
+            Self::Secrets => f.write_str("secrets"),
+            Self::Events => f.write_str("events"),
+            Self::InputEvents => f.write_str("events.input"),
+            Self::Clipboard => f.write_str("clipboard"),
+            Self::Net(h) => write!(f, "net:{h}"),
+            Self::Process(b) => write!(f, "process:{b}"),
+            Self::FsRead(p) => write!(f, "fs.read:{p}"),
+        }
+    }
+}
+
+impl FromStr for Capability {
+    type Err = String;
+
+    fn from_str(s: &str) -> Result<Self, String> {
+        let s = s.trim();
+        if let Some((kind, arg)) = s.split_once(':') {
+            let arg = arg.trim();
+            if arg.is_empty() {
+                return Err(format!("capability {s:?} needs a value after ':'"));
+            }
+            return match kind {
+                "net" => {
+                    let host = arg.strip_prefix("*.").unwrap_or(arg);
+                    let valid = !host.is_empty()
+                        && host.len() <= 253
+                        && host.split('.').all(|label| {
+                            !label.is_empty()
+                                && label.len() <= 63
+                                && label.bytes().all(|b| b.is_ascii_alphanumeric() || b == b'-')
+                        });
+                    if valid { Ok(Self::Net(arg.to_ascii_lowercase())) } else { Err(format!("invalid host in {s:?}")) }
+                }
+                "process" => {
+                    if arg.contains(['/', '\\']) && !std::path::Path::new(arg).is_absolute() {
+                        return Err(format!("{s:?}: use a program name or an absolute path"));
+                    }
+                    Ok(Self::Process(arg.to_owned()))
+                }
+                "fs.read" => {
+                    if !std::path::Path::new(arg).is_absolute() && !arg.starts_with('~') {
+                        return Err(format!("{s:?}: use an absolute path (or ~/…)"));
+                    }
+                    Ok(Self::FsRead(arg.to_owned()))
+                }
+                _ => Err(format!("unknown capability {s:?}")),
+            };
+        }
+        Ok(match s {
+            "project.read" | "project-read" => Self::ProjectRead,
+            "editor.read" | "editor-read" => Self::EditorRead,
+            "editor.write" | "editor-write" => Self::EditorWrite,
+            "vcs.read" => Self::VcsRead,
+            "vcs.write" => Self::VcsWrite,
+            "storage" => Self::Storage,
+            "secrets" => Self::Secrets,
+            "events" => Self::Events,
+            "events.input" => Self::InputEvents,
+            "clipboard" => Self::Clipboard,
+            _ => return Err(format!("unknown capability {s:?}")),
+        })
+    }
+}
+
+impl Serialize for Capability {
+    fn serialize<S: Serializer>(&self, s: S) -> Result<S::Ok, S::Error> {
+        s.collect_str(self)
+    }
+}
+
+impl<'de> Deserialize<'de> for Capability {
+    fn deserialize<D: Deserializer<'de>>(d: D) -> Result<Self, D::Error> {
+        String::deserialize(d)?.parse().map_err(serde::de::Error::custom)
+    }
+}
+
+/// A capability as the UI shows it.
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize, Type)]
+#[serde(rename_all = "camelCase")]
+pub struct CapabilityInfo {
+    /// `project.read`, `net:crates.io`, …
+    pub id: String,
+    pub risk: Risk,
+    pub description: String,
+    /// Declared under `optional`: the plugin runs without it.
+    pub optional: bool,
+    /// Currently granted.
+    pub granted: bool,
+}
+
+impl CapabilityInfo {
+    pub fn new(cap: &Capability, optional: bool, granted: bool) -> Self {
+        Self { id: cap.to_string(), risk: cap.risk(), description: cap.describe(), optional, granted }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn parses_and_prints() {
+        for s in [
+            "project.read",
+            "editor.write",
+            "vcs.write",
+            "storage",
+            "secrets",
+            "events",
+            "events.input",
+            "net:crates.io",
+            "net:*.github.com",
+            "process:cargo",
+        ] {
+            assert_eq!(s.parse::<Capability>().unwrap().to_string(), s);
+        }
+        // Absolute paths are the platform's.
+        let (git, etc) = if cfg!(windows) {
+            (r"process:C:\Program Files\Git\bin\git.exe", r"fs.read:C:\Windows")
+        } else {
+            ("process:/usr/bin/git", "fs.read:/etc")
+        };
+        for s in [git, etc] {
+            assert_eq!(s.parse::<Capability>().unwrap().to_string(), s);
+        }
+        assert_eq!("project-read".parse::<Capability>().unwrap(), Capability::ProjectRead);
+        assert!("net:".parse::<Capability>().is_err());
+        assert!("net:a b".parse::<Capability>().is_err());
+        assert!("process:./evil".parse::<Capability>().is_err());
+        assert!("fs.read:rel".parse::<Capability>().is_err());
+        assert!("network".parse::<Capability>().is_err());
+    }
+
+    #[test]
+    fn risk_levels() {
+        assert_eq!(Capability::ProjectRead.risk(), Risk::Low);
+        assert_eq!(Capability::Net("x".into()).risk(), Risk::Medium);
+        assert_eq!(Capability::InputEvents.risk(), Risk::Medium);
+        assert_eq!("clipboard".parse::<Capability>().unwrap(), Capability::Clipboard);
+        assert_eq!(Capability::Clipboard.risk(), Risk::Medium);
+        assert_eq!(Capability::Process("cargo".into()).risk(), Risk::High);
+        assert!(Capability::Storage.auto_migrates() && !Capability::EditorWrite.auto_migrates());
+    }
+
+    #[test]
+    fn host_patterns() {
+        assert!(host_matches("crates.io", "crates.io"));
+        assert!(host_matches("crates.io", "CRATES.IO."));
+        assert!(!host_matches("crates.io", "static.crates.io"));
+        assert!(host_matches("*.github.com", "api.github.com"));
+        assert!(!host_matches("*.github.com", "github.com"));
+        assert!(!host_matches("*.github.com", "evilgithub.com"));
+        let any_gh: Capability = "net:*.github.com".parse().unwrap();
+        assert!(any_gh.covers(&"net:api.github.com".parse().unwrap()));
+        assert!(Capability::FsRead("/etc".into()).covers(&Capability::FsRead("/etc/hosts".into())));
+        assert!(!Capability::FsRead("/etc".into()).covers(&Capability::FsRead("/etcx".into())));
+    }
+}
@@ -0,0 +1,104 @@
+//! The contribution index: validated UI
+//! declarations of installed packages, kept on disk so start-up does not
+//! validate them again (sanitising thousands of icon SVGs, say).
+//!
+//! Only packages with a [`Package::digest`] are indexed: installed copies,
+//! which the host never modifies after install. An entry is keyed by that
+//! digest, the extension point, the declaration and a salt naming the
+//! validation logic (the IDE version), so a new package version, a changed
+//! declaration or an IDE upgrade simply misses. A miss or an unreadable entry
+//! only costs the validation.
+
+use crate::point::Package;
+use crate::ui::UiDecl;
+use std::collections::BTreeSet;
+use std::path::PathBuf;
+
+/// Bumped when [`UiDecl`]'s serialized shape changes.
+const FORMAT: u32 = 1;
+
+pub struct ContributionIndex {
+    dir: PathBuf,
+    salt: String,
+}
+
+impl ContributionIndex {
+    /// `salt` names the validators' version (the IDE version).
+    pub fn new(dir: PathBuf, salt: &str) -> Self {
+        Self { dir, salt: format!("{FORMAT}:{salt}") }
+    }
+
+    /// Entries start with a prefix of the package digest, for pruning.
+    fn file(&self, digest: &str, point: &str, decl: &toml::Value) -> PathBuf {
+        let mut h = blake3::Hasher::new();
+        for part in [self.salt.as_str(), digest, point, &decl.to_string()] {
+            h.update(part.as_bytes());
+            h.update(&[0]);
+        }
+        let key = h.finalize().to_hex();
+        self.dir.join(format!("{}-{}.json", prefix(digest), &key[..32]))
+    }
+
+    pub fn get(&self, pkg: &Package, point: &str, decl: &toml::Value) -> Option<UiDecl> {
+        let digest = pkg.digest.as_deref()?;
+        let bytes = std::fs::read(self.file(digest, point, decl)).ok()?;
+        serde_json::from_slice(&bytes).ok()
+    }
+
+    pub fn put(&self, pkg: &Package, point: &str, decl: &toml::Value, ui: &UiDecl) {
+        let Some(digest) = pkg.digest.as_deref() else { return };
+        let Ok(bytes) = serde_json::to_vec(ui) else { return };
+        let file = self.file(digest, point, decl);
+        let _ = std::fs::create_dir_all(&self.dir);
+        let tmp = file.with_extension(format!("tmp{}", std::process::id()));
+        if std::fs::write(&tmp, bytes).and_then(|()| std::fs::rename(&tmp, &file)).is_err() {
+            let _ = std::fs::remove_file(&tmp);
+        }
+    }
+
+    /// Removes entries of packages other than `live` (digests).
+    pub fn prune<'a>(&self, live: impl IntoIterator<Item = &'a str>) {
+        let keep: BTreeSet<String> = live.into_iter().map(|d| prefix(d).to_owned()).collect();
+        let Ok(entries) = std::fs::read_dir(&self.dir) else { return };
+        for e in entries.flatten() {
+            let name = e.file_name().to_string_lossy().into_owned();
+            if !name.split_once('-').is_some_and(|(p, _)| keep.contains(p)) {
+                let _ = std::fs::remove_file(e.path());
+            }
+        }
+    }
+}
+
+fn prefix(digest: &str) -> &str {
+    let d = digest.strip_prefix("blake3:").unwrap_or(digest);
+    let end = d.char_indices().nth(16).map_or(d.len(), |(i, _)| i);
+    &d[..end]
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::manifest::Manifest;
+
+    #[test]
+    fn hits_only_the_same_package_point_declaration_and_salt() {
+        let tmp = tempfile::tempdir().unwrap();
+        let index = ContributionIndex::new(tmp.path().join("idx"), "1.0");
+        let manifest =
+            Manifest::parse("id = \"p\"\nname = \"P\"\nversion = \"1.0.0\"\nengines.openidea = \"^1.0\"\n").unwrap();
+        let pkg = Package::new(manifest, tmp.path().to_path_buf()).with_digest("blake3:00aa11bb22cc33dd44ee");
+        let decl: toml::Value = toml::from_str("id = \"x\"").unwrap();
+        let ui = UiDecl::new("x", "X", serde_json::json!({ "id": "x" }));
+        assert!(index.get(&pkg, "pt", &decl).is_none());
+        index.put(&pkg, "pt", &decl, &ui);
+        assert_eq!(index.get(&pkg, "pt", &decl).unwrap().label, "X");
+        assert!(index.get(&pkg, "other", &decl).is_none());
+        assert!(index.get(&pkg, "pt", &toml::from_str("id = \"y\"").unwrap()).is_none());
+        assert!(ContributionIndex::new(tmp.path().join("idx"), "1.1").get(&pkg, "pt", &decl).is_none());
+        let unhashed = Package { digest: None, ..pkg.clone() };
+        assert!(index.get(&unhashed, "pt", &decl).is_none(), "not an installed copy");
+
+        index.prune(["blake3:ffff"]);
+        assert!(index.get(&pkg, "pt", &decl).is_none());
+    }
+}
@@ -0,0 +1,505 @@
+//! The grant ledger (plan 4.6): which capabilities the user granted to which
+//! plugin, saved as `grants.json` next to the installed plugins.
+//!
+//! - Installed plugins are keyed by id and remember the version and package
+//!   hash they were confirmed for. An update that needs no new capability is
+//!   accepted silently; one that does must be confirmed again.
+//! - Linked development plugins and project plugins (`.openidea/plugins/*`)
+//!   are keyed by their directory, not by hash, so rebuilding does not ask
+//!   again; new capabilities still do.
+//! - `process:<program>` grants record the program's absolute path and file
+//!   hash at grant time. Calls use that path, never a `PATH` lookup, and fail
+//!   when the file changed (re-confirmation needed).
+
+use crate::capability::{Capability, Risk};
+use serde::{Deserialize, Serialize};
+use std::collections::{BTreeMap, BTreeSet};
+use std::ffi::OsStr;
+use std::path::{Path, PathBuf};
+
+pub const LEDGER_FILE: &str = "grants.json";
+const FORMAT: u32 = 1;
+
+/// Whose grant an entry is.
+#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize)]
+#[serde(tag = "kind", content = "value", rename_all = "camelCase")]
+pub enum Subject {
+    /// Installed under the plugins directory, by plugin id.
+    Installed(String),
+    /// A linked development plugin or a project plugin, by package directory.
+    Path(PathBuf),
+}
+
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct BinaryGrant {
+    pub path: PathBuf,
+    /// blake3 of the file when granted.
+    pub hash: String,
+}
+
+#[derive(Clone, Debug, Default, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct Grant {
+    pub plugin_id: String,
+    /// The version and package hash the user confirmed (installed plugins).
+    #[serde(default)]
+    pub version: String,
+    #[serde(default)]
+    pub package_hash: String,
+    /// The user confirmed the plugin (the install page or the project-plugin prompt).
+    #[serde(default)]
+    pub confirmed: bool,
+    /// Granted capabilities (`project.read`, `net:x`, …).
+    #[serde(default)]
+    pub granted: BTreeSet<String>,
+    /// Optional capabilities the user declined (not asked again until re-confirmed).
+    #[serde(default)]
+    pub declined: BTreeSet<String>,
+    /// `process:<program>` → the program confirmed for it.
+    #[serde(default)]
+    pub binaries: BTreeMap<String, BinaryGrant>,
+    /// Migrated from 0.1: capabilities not granted yet are asked for on first
+    /// use instead of blocking the plugin from loading.
+    #[serde(default)]
+    pub ask_on_use: bool,
+}
+
+impl Grant {
+    pub fn has(&self, cap: &Capability) -> bool {
+        self.granted.iter().filter_map(|s| s.parse::<Capability>().ok()).any(|g| g.covers(cap))
+    }
+}
+
+/// What a plugin (in its current form) needs, to compare with its grant.
+#[derive(Clone, Debug)]
+pub struct Request<'a> {
+    pub subject: Subject,
+    pub plugin_id: &'a str,
+    pub version: &'a str,
+    pub package_hash: &'a str,
+    pub required: Vec<Capability>,
+    pub optional: Vec<Capability>,
+}
+
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub enum Decision {
+    /// Load with these capabilities. `pending` required ones are asked for when
+    /// the plugin is first used (plugins migrated from 0.1 only).
+    Allowed { granted: Vec<Capability>, pending: Vec<Capability> },
+    /// Ask the user first. `new` lists what was never granted (all of it on first use).
+    NeedsConfirmation { new: Vec<Capability>, first_time: bool },
+}
+
+#[derive(Debug, Default, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+struct File {
+    #[serde(default)]
+    format: u32,
+    /// The one-time migration from 0.1 ("declared means granted") ran.
+    #[serde(default)]
+    migrated: bool,
+    #[serde(default)]
+    grants: Vec<(Subject, Grant)>,
+}
+
+/// The ledger, loaded into memory; [`Ledger::save`] writes it atomically.
+#[derive(Debug, Default)]
+pub struct Ledger {
+    path: Option<PathBuf>,
+    migrated: bool,
+    grants: BTreeMap<Subject, Grant>,
+}
+
+impl Ledger {
+    /// Loads `<dir>/grants.json`; a missing or unreadable file gives an empty
+    /// ledger with `needs_migration()` true.
+    pub fn load(dir: &Path) -> Self {
+        let path = dir.join(LEDGER_FILE);
+        let file: Option<File> = std::fs::read_to_string(&path).ok().and_then(|s| match serde_json::from_str(&s) {
+            Ok(f) => Some(f),
+            Err(e) => {
+                tracing::warn!("{}: {e}; starting with an empty grant ledger", path.display());
+                None
+            }
+        });
+        let existed = file.is_some();
+        let file = file.unwrap_or_default();
+        Self { path: Some(path), migrated: file.migrated || existed, grants: file.grants.into_iter().collect() }
+    }
+
+    pub fn in_memory() -> Self {
+        Self { path: None, migrated: true, grants: BTreeMap::new() }
+    }
+
+    pub fn save(&self) -> std::io::Result<()> {
+        let Some(path) = &self.path else { return Ok(()) };
+        let file = File {
+            format: FORMAT,
+            migrated: self.migrated,
+            grants: self.grants.iter().map(|(s, g)| (s.clone(), g.clone())).collect(),
+        };
+        let json = serde_json::to_string_pretty(&file).map_err(std::io::Error::other)?;
+        let tmp = path.with_extension("json.tmp");
+        std::fs::write(&tmp, json)?;
+        std::fs::rename(&tmp, path)
+    }
+
+    pub fn get(&self, subject: &Subject) -> Option<&Grant> {
+        self.grants.get(subject)
+    }
+
+    pub fn remove(&mut self, subject: &Subject) -> Option<Grant> {
+        self.grants.remove(subject)
+    }
+
+    /// Puts back an earlier state of `subject`'s grant (`None`: none), e.g.
+    /// after rolling back an update.
+    pub fn restore(&mut self, subject: &Subject, grant: Option<Grant>) {
+        match grant {
+            Some(g) => {
+                self.grants.insert(subject.clone(), g);
+            }
+            None => {
+                self.grants.remove(subject);
+            }
+        }
+    }
+
+    /// The one-time migration of 0.1's "declared means granted" has not run yet.
+    pub fn needs_migration(&self) -> bool {
+        !self.migrated
+    }
+
+    /// Migrates plugins installed before the ledger existed: low-risk
+    /// capabilities are granted, the rest are asked on first use.
+    pub fn migrate(&mut self, installed: &[Request<'_>]) {
+        for req in installed {
+            let granted: BTreeSet<String> =
+                req.required.iter().chain(&req.optional).filter(|c| c.auto_migrates()).map(|c| c.to_string()).collect();
+            self.grants.entry(req.subject.clone()).or_insert_with(|| Grant {
+                plugin_id: req.plugin_id.to_owned(),
+                version: req.version.to_owned(),
+                package_hash: req.package_hash.to_owned(),
+                confirmed: true,
+                granted,
+                ask_on_use: true,
+                ..Grant::default()
+            });
+        }
+        self.migrated = true;
+    }
+
+    /// Compares what the plugin needs with what was granted.
+    pub fn decide(&mut self, req: &Request<'_>) -> Decision {
+        let Some(grant) = self.grants.get_mut(&req.subject) else {
+            return Decision::NeedsConfirmation { new: req.required.clone(), first_time: true };
+        };
+        if !grant.confirmed {
+            return Decision::NeedsConfirmation { new: req.required.clone(), first_time: true };
+        }
+        let new: Vec<Capability> = req.required.iter().filter(|c| !grant.has(c)).cloned().collect();
+        if !new.is_empty() && !grant.ask_on_use {
+            return Decision::NeedsConfirmation { new, first_time: false };
+        }
+        // Same or fewer needs: accept an update silently (plan 4.6).
+        if grant.version != req.version || grant.package_hash != req.package_hash {
+            grant.version = req.version.to_owned();
+            grant.package_hash = req.package_hash.to_owned();
+        }
+        let granted = req.required.iter().chain(&req.optional).filter(|c| grant.has(c)).cloned().collect();
+        Decision::Allowed { granted, pending: new }
+    }
+
+    /// Records the user's confirmation: `required` plus the accepted optional capabilities.
+    pub fn confirm(
+        &mut self,
+        req: &Request<'_>,
+        accepted_optional: &[Capability],
+        binaries: BTreeMap<String, BinaryGrant>,
+    ) {
+        let grant = self.grants.entry(req.subject.clone()).or_default();
+        grant.plugin_id = req.plugin_id.to_owned();
+        grant.version = req.version.to_owned();
+        grant.package_hash = req.package_hash.to_owned();
+        grant.confirmed = true;
+        grant.ask_on_use = false;
+        for cap in req.required.iter().chain(accepted_optional) {
+            grant.granted.insert(cap.to_string());
+        }
+        for cap in &req.optional {
+            let s = cap.to_string();
+            if accepted_optional.contains(cap) {
+                grant.declined.remove(&s);
+            } else if !grant.granted.contains(&s) {
+                grant.declined.insert(s);
+            }
+        }
+        grant.binaries.extend(binaries);
+    }
+
+    /// Grants or revokes one capability (Settings › Plugins › permissions).
+    pub fn set(&mut self, subject: &Subject, cap: &Capability, granted: bool) -> bool {
+        let Some(grant) = self.grants.get_mut(subject) else { return false };
+        let s = cap.to_string();
+        if granted {
+            grant.declined.remove(&s);
+            grant.granted.insert(s)
+        } else {
+            if let Capability::Process(_) = cap {
+                grant.binaries.remove(&s);
+            }
+            grant.granted.remove(&s)
+        }
+    }
+
+    /// Records the program approved for a `process:` grant.
+    pub fn set_binary(&mut self, subject: &Subject, cap: &Capability, binary: BinaryGrant) {
+        if let Some(grant) = self.grants.get_mut(subject) {
+            grant.binaries.insert(cap.to_string(), binary);
+        }
+    }
+
+    /// Checks a `process:` grant at call time: the program confirmed for it,
+    /// unchanged since. Errors name what to do.
+    pub fn check_binary(&self, subject: &Subject, cap: &Capability) -> Result<PathBuf, String> {
+        let Capability::Process(name) = cap else { return Err(format!("{cap} is not a process capability")) };
+        let grant = self.grants.get(subject).ok_or_else(|| format!("{cap} was not granted"))?;
+        let key = cap.to_string();
+        if !grant.granted.contains(&key) {
+            return Err(format!("{cap} was not granted"));
+        }
+        let bin = grant.binaries.get(&key).ok_or_else(|| format!("{cap}: no program was confirmed for {name}"))?;
+        match file_hash(&bin.path) {
+            Ok(hash) if hash == bin.hash => Ok(bin.path.clone()),
+            Ok(_) => Err(format!(
+                "{} changed since it was approved for {cap}; confirm the plugin's permissions again",
+                bin.path.display()
+            )),
+            Err(e) => Err(format!("{}: {e}; confirm the plugin's permissions again", bin.path.display())),
+        }
+    }
+
+    /// The program approved for a granted `process:` capability, without
+    /// checking the file: whoever starts it verifies the hash then
+    /// ([`check_binary`](Self::check_binary) or the pin's own check).
+    pub fn pinned_binary(&self, subject: &Subject, cap: &Capability) -> Option<BinaryGrant> {
+        let grant = self.grants.get(subject)?;
+        let key = cap.to_string();
+        if !grant.granted.contains(&key) {
+            return None;
+        }
+        grant.binaries.get(&key).cloned()
+    }
+
+    pub fn subjects(&self) -> impl Iterator<Item = (&Subject, &Grant)> {
+        self.grants.iter()
+    }
+}
+
+/// What a confirmation page shows: every capability with its risk, high risk first.
+pub fn by_risk(caps: &[Capability]) -> Vec<(Risk, Vec<Capability>)> {
+    let mut groups: BTreeMap<std::cmp::Reverse<Risk>, Vec<Capability>> = BTreeMap::new();
+    for c in caps {
+        groups.entry(std::cmp::Reverse(c.risk())).or_default().push(c.clone());
+    }
+    groups.into_iter().map(|(r, v)| (r.0, v)).collect()
+}
+
+/// Resolves a `process:` program to an absolute path once, at grant time:
+/// absolute names are taken as is, others are looked up in `path_var`.
+pub fn resolve_program(name: &str, path_var: Option<&OsStr>) -> Result<PathBuf, String> {
+    let candidate = Path::new(name);
+    if candidate.is_absolute() {
+        return if candidate.is_file() { Ok(candidate.to_path_buf()) } else { Err(format!("{name}: no such program")) };
+    }
+    let exts: Vec<String> = if cfg!(windows) {
+        std::env::var("PATHEXT").unwrap_or_else(|_| ".EXE;.CMD;.BAT".into()).split(';').map(str::to_owned).collect()
+    } else {
+        vec![String::new()]
+    };
+    for dir in std::env::split_paths(path_var.unwrap_or_default()) {
+        if !dir.is_absolute() {
+            continue; // `.` or relative entries could point into the project
+        }
+        for ext in &exts {
+            let p = dir.join(format!("{name}{ext}"));
+            if is_executable(&p) {
+                return Ok(dunce_canonical(&p));
+            }
+        }
+    }
+    Err(format!("{name} was not found on PATH"))
+}
+
+fn dunce_canonical(p: &Path) -> PathBuf {
+    std::fs::canonicalize(p).unwrap_or_else(|_| p.to_path_buf())
+}
+
+fn is_executable(p: &Path) -> bool {
+    let Ok(meta) = std::fs::metadata(p) else { return false };
+    if !meta.is_file() {
+        return false;
+    }
+    #[cfg(unix)]
+    {
+        use std::os::unix::fs::PermissionsExt;
+        meta.permissions().mode() & 0o111 != 0
+    }
+    #[cfg(not(unix))]
+    true
+}
+
+/// blake3 of a file, hex.
+pub fn file_hash(path: &Path) -> std::io::Result<String> {
+    let mut hasher = blake3::Hasher::new();
+    hasher.update_reader(std::fs::File::open(path)?)?;
+    Ok(hasher.finalize().to_hex().to_string())
+}
+
+/// blake3 over a package's files (sorted relative paths and contents).
+pub fn package_hash(dir: &Path, files: &[PathBuf]) -> std::io::Result<String> {
+    let mut sorted: Vec<&PathBuf> = files.iter().collect();
+    sorted.sort();
+    sorted.dedup();
+    let mut hasher = blake3::Hasher::new();
+    for rel in sorted {
+        hasher.update(hashed_path(rel).as_bytes());
+        hasher.update(&[0]);
+        hasher.update_reader(std::fs::File::open(dir.join(rel))?)?;
+        hasher.update(&[0]);
+    }
+    Ok(hasher.finalize().to_hex().to_string())
+}
+
+/// A package-relative path as hashed: `/`-separated on every OS, so a package has one digest
+/// (a walked `web\index.html` on Windows is `web/index.html` everywhere else).
+fn hashed_path(rel: &Path) -> String {
+    rel.components().map(|c| c.as_os_str().to_string_lossy()).collect::<Vec<_>>().join("/")
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn caps(list: &[&str]) -> Vec<Capability> {
+        list.iter().map(|s| s.parse().unwrap()).collect()
+    }
+
+    fn req<'a>(version: &'a str, hash: &'a str, required: &[&str], optional: &[&str]) -> Request<'a> {
+        Request {
+            subject: Subject::Installed("p".into()),
+            plugin_id: "p",
+            version,
+            package_hash: hash,
+            required: caps(required),
+            optional: caps(optional),
+        }
+    }
+
+    #[test]
+    fn confirmation_then_silent_update_then_reconfirm_on_new_capability() {
+        let mut l = Ledger::in_memory();
+        let r1 = req("1.0.0", "h1", &["project.read"], &["net:crates.io"]);
+        assert_eq!(l.decide(&r1), Decision::NeedsConfirmation { new: caps(&["project.read"]), first_time: true });
+        l.confirm(&r1, &[], BTreeMap::new());
+        assert_eq!(
+            l.decide(&r1),
+            Decision::Allowed { granted: caps(&["project.read"]), pending: vec![] },
+            "declined optional"
+        );
+        assert!(l.get(&r1.subject).unwrap().declined.contains("net:crates.io"));
+
+        // Same needs, new version: silent.
+        let r2 = req("1.1.0", "h2", &["project.read"], &["net:crates.io"]);
+        assert!(matches!(l.decide(&r2), Decision::Allowed { .. }));
+        assert_eq!(l.get(&r2.subject).unwrap().version, "1.1.0");
+
+        // A new required capability: ask again, only for it.
+        let r3 = req("1.2.0", "h3", &["project.read", "editor.write"], &[]);
+        assert_eq!(l.decide(&r3), Decision::NeedsConfirmation { new: caps(&["editor.write"]), first_time: false });
+        l.confirm(&r3, &[], BTreeMap::new());
+        assert!(matches!(l.decide(&r3), Decision::Allowed { .. }));
+
+        // Revoking a required capability blocks loading again.
+        assert!(l.set(&r3.subject, &Capability::EditorWrite, false));
+        assert!(matches!(l.decide(&r3), Decision::NeedsConfirmation { .. }));
+    }
+
+    #[test]
+    fn migration_grants_low_risk_only() {
+        let tmp = tempfile::tempdir().unwrap();
+        let mut l = Ledger::load(tmp.path());
+        assert!(l.needs_migration());
+        let r = req("0.1.0", "h", &["project.read", "editor.write"], &[]);
+        l.migrate(std::slice::from_ref(&r));
+        // Loads with the low-risk part; the rest is asked for on first use.
+        assert_eq!(
+            l.decide(&r),
+            Decision::Allowed { granted: caps(&["project.read"]), pending: caps(&["editor.write"]) }
+        );
+        l.confirm(&r, &[], BTreeMap::new());
+        assert_eq!(
+            l.decide(&r),
+            Decision::Allowed { granted: caps(&["project.read", "editor.write"]), pending: vec![] }
+        );
+        l.save().unwrap();
+        let again = Ledger::load(tmp.path());
+        assert!(!again.needs_migration());
+        assert!(again.get(&r.subject).unwrap().has(&Capability::ProjectRead));
+    }
+
+    #[cfg(unix)]
+    #[test]
+    fn binaries_are_pinned_by_path_and_hash() {
+        use std::os::unix::fs::PermissionsExt;
+        let tmp = tempfile::tempdir().unwrap();
+        let bin_dir = tmp.path().join("bin");
+        std::fs::create_dir(&bin_dir).unwrap();
+        let tool = bin_dir.join("tool");
+        std::fs::write(&tool, "#!/bin/sh\necho v1\n").unwrap();
+        std::fs::set_permissions(&tool, std::fs::Permissions::from_mode(0o755)).unwrap();
+        let path_var = std::env::join_paths([PathBuf::from("relative"), bin_dir.clone()]).unwrap();
+        let resolved = resolve_program("tool", Some(&path_var)).unwrap();
+        assert!(resolved.is_absolute());
+        assert!(resolve_program("missing", Some(&path_var)).is_err());
+
+        let mut l = Ledger::in_memory();
+        let r = req("1.0.0", "h", &["process:tool"], &[]);
+        let cap: Capability = "process:tool".parse().unwrap();
+        let bin = BinaryGrant { path: resolved.clone(), hash: file_hash(&resolved).unwrap() };
+        l.confirm(&r, &[], [(cap.to_string(), bin)].into());
+        assert_eq!(l.check_binary(&r.subject, &cap).unwrap(), resolved);
+        std::fs::write(&tool, "#!/bin/sh\necho evil\n").unwrap();
+        assert!(l.check_binary(&r.subject, &cap).unwrap_err().contains("changed"));
+    }
+
+    #[test]
+    fn hashes_and_grouping() {
+        let tmp = tempfile::tempdir().unwrap();
+        std::fs::write(tmp.path().join("a"), "1").unwrap();
+        std::fs::write(tmp.path().join("b"), "2").unwrap();
+        let h1 = package_hash(tmp.path(), &["a".into(), "b".into()]).unwrap();
+        assert_eq!(h1, package_hash(tmp.path(), &["b".into(), "a".into()]).unwrap());
+        std::fs::write(tmp.path().join("b"), "3").unwrap();
+        assert_ne!(h1, package_hash(tmp.path(), &["a".into(), "b".into()]).unwrap());
+        let groups = by_risk(&caps(&["storage", "process:git", "net:x.io"]));
+        assert_eq!(groups.iter().map(|g| g.0).collect::<Vec<_>>(), [Risk::High, Risk::Medium, Risk::Low]);
+    }
+
+    #[test]
+    fn hashes_paths_with_forward_slashes_on_every_os() {
+        assert_eq!(hashed_path(Path::new("web/index.html")), "web/index.html");
+        assert_eq!(hashed_path(Path::new("plugin.wasm")), "plugin.wasm");
+        #[cfg(windows)]
+        assert_eq!(hashed_path(Path::new(r"web\index.html")), "web/index.html");
+        let tmp = tempfile::tempdir().unwrap();
+        std::fs::create_dir(tmp.path().join("web")).unwrap();
+        std::fs::write(tmp.path().join("web").join("index.html"), "<p>").unwrap();
+        // A walked path (native separators) hashes like the manifest's `/` spelling.
+        assert_eq!(
+            package_hash(tmp.path(), &[Path::new("web").join("index.html")]).unwrap(),
+            package_hash(tmp.path(), &["web/index.html".into()]).unwrap()
+        );
+    }
+}
@@ -0,0 +1,36 @@
+//! The plugin system's kernel, independent of the Wasm runtime:
+//!
+//! - [`Manifest`]: `plugin.toml` (0.2 format; 0.1 still parses);
+//! - [`Capability`]: what a plugin may do, with its [`Risk`] level;
+//! - [`ExtensionPoint`]: one kind of contribution, implemented by the crate that
+//!   owns the feature; [`ExtensionRegistry`] validates a package's declarations
+//!   ([`ExtensionRegistry::prepare`], no side effects), makes them take effect
+//!   all or nothing ([`ExtensionRegistry::commit`]) and withdraws them per plugin;
+//! - [`UiStore`] / [`UiPoint`]: UI contributions, validated here and projected
+//!   by the client without the possibility to fail;
+//! - [`ledger`]: which capabilities the user granted to which plugin;
+//! - [`package`]: the package file, its signature and the marketplace index.
+//!
+//! Dependency direction: `ide-core` ← `ide-extension` ← feature crates (their
+//! extension points) and `ide-plugin` (Wasm) ← `ide-host` (assembly).
+
+mod capability;
+mod index;
+pub mod ledger;
+mod manifest;
+pub mod package;
+mod point;
+mod registry;
+mod ui;
+mod when;
+
+pub use capability::{Capability, CapabilityInfo, Risk, host_matches};
+pub use index::ContributionIndex;
+pub use manifest::{
+    ActivationEvent, CATEGORIES, Capabilities, ENGINE_VERSION, EVENT_KINDS, LEGACY_API, MANIFEST_FILE, MAX_CATEGORIES,
+    Manifest, check_relative, engine_compatible, validate_item_id, validate_plugin_id, validate_point_id,
+};
+pub use point::{Commit, Disposable, ExtensionPoint, MAX_PACKAGE_FILE, Package, Placement, Prepared, decode};
+pub use registry::{ContributionInfo, ExtensionRegistry, PreparedSet};
+pub use ui::{UiContribution, UiDecl, UiPoint, UiStore, to_json};
+pub use when::validate_when;
@@ -0,0 +1,567 @@
+//! `plugin.toml`, the package manifest (plan 4.4).
+//!
+//! ```toml
+//! id = "acme.rust-tools"          # optional publisher namespace before the first '.'
+//! name = "Rust Tools"
+//! version = "1.2.0"
+//! engines.openidea = "^1.0"
+//! wasm = "plugin.wasm"
+//! activation = ["on-language:rust", "on-command:check"]
+//!
+//! [capabilities]
+//! required = ["project.read", "editor.write"]
+//! optional = ["net:crates.io", "process:cargo"]
+//!
+//! [[contributes.commands]]
+//! id = "check"
+//! title = "Check"
+//! ```
+//!
+//! `contributes` is kept as raw TOML: each `contributes.<point>` is parsed and
+//! validated by the extension point registered under that id
+//! ([`crate::ExtensionRegistry`]), so new contribution types need no change here.
+//!
+//! Manifests in the 0.1 format (`openidea-api = "0.1"`, `permissions = [...]`)
+//! still parse: permissions become required capabilities and the plugin is
+//! activated at start-up, as before.
+
+use crate::capability::Capability;
+use serde::Deserialize;
+use std::collections::BTreeSet;
+use std::path::{Component, Path, PathBuf};
+
+pub const MANIFEST_FILE: &str = "plugin.toml";
+/// The plugin API (engine) version this host implements.
+pub const ENGINE_VERSION: &str = "1.1.0";
+/// The 0.1 API, still accepted for contribution-only packages and 0.1 components.
+pub const LEGACY_API: &str = "0.1";
+/// Marketplace categories, in the order they are shown.
+pub const CATEGORIES: &[&str] =
+    &["languages", "themes", "icon-themes", "linters", "vcs", "ai", "frameworks", "tools", "other"];
+/// Categories a plugin is listed under; later ones are ignored.
+pub const MAX_CATEGORIES: usize = 3;
+
+#[derive(Clone, Debug, PartialEq)]
+pub struct Manifest {
+    pub id: String,
+    pub name: String,
+    pub version: String,
+    pub description: String,
+    pub authors: Vec<String>,
+    pub homepage: Option<String>,
+    pub license: Option<String>,
+    /// Release notes of this version (Settings › Plugins › What's New).
+    pub change_notes: Option<String>,
+    /// Marketplace categories as declared (see [`Manifest::categories`]).
+    pub declared_categories: Vec<String>,
+    /// `engines.openidea` (a semver requirement), or the legacy `openidea-api`.
+    pub engine: String,
+    /// Written in the 0.1 format.
+    pub legacy: bool,
+    /// Component file relative to the package directory.
+    pub wasm: Option<PathBuf>,
+    pub activation: Vec<ActivationEvent>,
+    pub capabilities: Capabilities,
+    /// `contributes.<point>` → its declarations, validated by the extension points.
+    pub contributes: toml::Table,
+}
+
+#[derive(Clone, Debug, Default, PartialEq, Eq)]
+pub struct Capabilities {
+    pub required: Vec<Capability>,
+    pub optional: Vec<Capability>,
+}
+
+impl Capabilities {
+    pub fn all(&self) -> impl Iterator<Item = &Capability> {
+        self.required.iter().chain(&self.optional)
+    }
+
+    pub fn is_optional(&self, cap: &Capability) -> bool {
+        self.optional.contains(cap) && !self.required.contains(cap)
+    }
+}
+
+/// When a plugin's code is instantiated (plan 4.4). Contributions are live
+/// without it; code only runs once one of these fires.
+#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub enum ActivationEvent {
+    /// One of the plugin's commands is run (`on-command:<id>`; `*` = any).
+    Command(String),
+    /// A file of this language is opened.
+    Language(String),
+    /// A file matching this glob (project-relative) is opened.
+    File(String),
+    /// One of the plugin's views is shown.
+    View(String),
+    /// Periodically: `on-schedule:<seconds>`. Does not keep the plugin alive.
+    Schedule(u32),
+    /// A workbench event of this kind (`on-event:file-saved`): the plugin is
+    /// subscribed from the start, and activated to receive it.
+    Event(String),
+    /// Shortly after the workbench is ready.
+    StartupFinished,
+}
+
+impl ActivationEvent {
+    pub fn parse(s: &str) -> Result<Self, String> {
+        let s = s.trim();
+        if s == "on-startup-finished" {
+            return Ok(Self::StartupFinished);
+        }
+        let (kind, arg) = s.split_once(':').ok_or_else(|| format!("unknown activation event {s:?}"))?;
+        let arg = arg.trim();
+        if arg.is_empty() {
+            return Err(format!("activation event {s:?} needs a value"));
+        }
+        Ok(match kind {
+            "on-command" => Self::Command(arg.into()),
+            "on-language" => Self::Language(arg.into()),
+            "on-file" => Self::File(arg.into()),
+            "on-view" => Self::View(arg.into()),
+            "on-schedule" => {
+                let secs: u32 =
+                    arg.trim_end_matches('s').parse().map_err(|_| format!("{s:?}: expected seconds, e.g. 300"))?;
+                if secs < 60 {
+                    return Err(format!("{s:?}: the shortest schedule is 60 seconds"));
+                }
+                Self::Schedule(secs)
+            }
+            "on-event" => {
+                if !EVENT_KINDS.contains(&arg) {
+                    return Err(format!("{s:?}: unknown event kind (one of {})", EVENT_KINDS.join(", ")));
+                }
+                Self::Event(arg.into())
+            }
+            _ => return Err(format!("unknown activation event {s:?}")),
+        })
+    }
+}
+
+/// Workbench event kinds (`on-event:<kind>`, WIT `events.event-kind`).
+/// `scheduled` comes from `on-schedule` instead.
+pub const EVENT_KINDS: &[&str] = &["file-opened", "file-saved", "editor-focused", "action-performed", "vcs-changed"];
+
+impl std::fmt::Display for ActivationEvent {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Self::Command(c) => write!(f, "on-command:{c}"),
+            Self::Language(l) => write!(f, "on-language:{l}"),
+            Self::File(g) => write!(f, "on-file:{g}"),
+            Self::View(v) => write!(f, "on-view:{v}"),
+            Self::Schedule(s) => write!(f, "on-schedule:{s}"),
+            Self::Event(k) => write!(f, "on-event:{k}"),
+            Self::StartupFinished => f.write_str("on-startup-finished"),
+        }
+    }
+}
+
+#[derive(Deserialize)]
+#[serde(rename_all = "kebab-case", deny_unknown_fields)]
+struct Raw {
+    id: String,
+    name: String,
+    version: String,
+    #[serde(default)]
+    description: String,
+    #[serde(default)]
+    authors: Vec<String>,
+    #[serde(default)]
+    homepage: Option<String>,
+    #[serde(default)]
+    license: Option<String>,
+    #[serde(default)]
+    change_notes: Option<String>,
+    #[serde(default)]
+    categories: Vec<String>,
+    #[serde(default)]
+    engines: Option<Engines>,
+    /// 0.1 format.
+    #[serde(default)]
+    openidea_api: Option<String>,
+    #[serde(default)]
+    wasm: Option<PathBuf>,
+    #[serde(default)]
+    activation: Option<Vec<String>>,
+    #[serde(default)]
+    capabilities: Option<RawCapabilities>,
+    /// 0.1 format.
+    #[serde(default)]
+    permissions: Option<Vec<String>>,
+    #[serde(default)]
+    contributes: toml::Table,
+}
+
+#[derive(Deserialize)]
+#[serde(deny_unknown_fields)]
+struct Engines {
+    openidea: String,
+}
+
+#[derive(Deserialize)]
+#[serde(deny_unknown_fields)]
+struct RawCapabilities {
+    #[serde(default)]
+    required: Vec<String>,
+    #[serde(default)]
+    optional: Vec<String>,
+}
+
+impl Manifest {
+    pub fn parse(src: &str) -> Result<Self, String> {
+        let raw: Raw = toml::from_str(src).map_err(|e| e.to_string())?;
+        let (engine, legacy) = match (raw.engines, raw.openidea_api) {
+            (Some(e), None) => (e.openidea, false),
+            (None, Some(api)) => (api, true),
+            (Some(_), Some(_)) => return Err("use `engines.openidea`, not `openidea-api`".into()),
+            (None, None) => return Err("missing `engines.openidea` (e.g. \"^1.0\")".into()),
+        };
+        if legacy && raw.capabilities.is_some() {
+            return Err("`capabilities` requires `engines.openidea`; 0.1 manifests use `permissions`".into());
+        }
+        if !legacy && raw.permissions.is_some() {
+            return Err("`permissions` is the 0.1 format; use `[capabilities] required = [...]`".into());
+        }
+        let parse_caps = |list: Vec<String>| -> Result<Vec<Capability>, String> {
+            let mut out: Vec<Capability> = Vec::new();
+            for s in list {
+                let cap: Capability = s.parse()?;
+                if !out.contains(&cap) {
+                    out.push(cap);
+                }
+            }
+            Ok(out)
+        };
+        let capabilities = match (raw.capabilities, raw.permissions) {
+            (Some(c), _) => Capabilities { required: parse_caps(c.required)?, optional: parse_caps(c.optional)? },
+            (None, Some(p)) => Capabilities { required: parse_caps(p)?, optional: Vec::new() },
+            (None, None) => Capabilities::default(),
+        };
+        let activation = match raw.activation {
+            Some(list) => list.iter().map(|s| ActivationEvent::parse(s)).collect::<Result<Vec<_>, _>>()?,
+            // 0.1 plugins were activated at start-up; keep that until they move to 1.0.
+            None if legacy && raw.wasm.is_some() => vec![ActivationEvent::StartupFinished],
+            None => Vec::new(),
+        };
+        let m = Manifest {
+            id: raw.id,
+            name: raw.name,
+            version: raw.version,
+            description: raw.description,
+            authors: raw.authors,
+            homepage: raw.homepage,
+            license: raw.license,
+            change_notes: raw.change_notes,
+            declared_categories: raw.categories,
+            engine,
+            legacy,
+            wasm: raw.wasm,
+            activation,
+            capabilities,
+            contributes: raw.contributes,
+        };
+        m.validate()?;
+        Ok(m)
+    }
+
+    pub fn load(dir: &Path) -> Result<Self, String> {
+        let path = dir.join(MANIFEST_FILE);
+        let src = std::fs::read_to_string(&path).map_err(|e| format!("{}: {e}", path.display()))?;
+        Self::parse(&src).map_err(|e| format!("{}: {e}", path.display()))
+    }
+
+    fn validate(&self) -> Result<(), String> {
+        validate_plugin_id(&self.id)?;
+        if self.name.trim().is_empty() {
+            return Err("`name` must not be empty".into());
+        }
+        if semver::Version::parse(&self.version).is_err() {
+            return Err(format!("`version` must be a semantic version like 1.2.3, got {:?}", self.version));
+        }
+        if !engine_compatible(&self.engine, self.legacy) {
+            return Err(if self.legacy {
+                format!(
+                    "unsupported openidea-api {:?} (this IDE implements {LEGACY_API} and {ENGINE_VERSION})",
+                    self.engine
+                )
+            } else {
+                format!("engines.openidea {:?} does not match this IDE's plugin API {ENGINE_VERSION}", self.engine)
+            });
+        }
+        if let Some(wasm) = &self.wasm {
+            check_relative(wasm, "wasm")?;
+        }
+        if self.wasm.is_none() && !self.activation.is_empty() {
+            return Err("`activation` needs `wasm`: there is no code to activate".into());
+        }
+        let mut seen = BTreeSet::new();
+        for event in &self.activation {
+            if !seen.insert(event) {
+                return Err(format!("duplicate activation event {event}"));
+            }
+        }
+        for c in &self.declared_categories {
+            validate_item_id(c, "category")?;
+        }
+        for (point, decls) in &self.contributes {
+            validate_point_id(point)?;
+            if !matches!(decls, toml::Value::Array(_) | toml::Value::Table(_)) {
+                return Err(format!("`contributes.{point}` must be a table or an array of tables"));
+            }
+        }
+        Ok(())
+    }
+
+    /// The declarations of one extension point: `[[contributes.x]]` gives
+    /// several, `[contributes.x]` one.
+    pub fn declarations(&self, point: &str) -> Vec<toml::Value> {
+        match self.contributes.get(point) {
+            Some(toml::Value::Array(items)) => items.clone(),
+            Some(single @ toml::Value::Table(_)) => vec![single.clone()],
+            _ => Vec::new(),
+        }
+    }
+
+    /// Number of declarations per extension point (for listings before loading).
+    pub fn declaration_counts(&self) -> Vec<(String, u32)> {
+        self.contributes.keys().map(|p| (p.clone(), self.declarations(p).len() as u32)).collect()
+    }
+
+    /// Publisher namespace: the id's part before the first `.` (`acme` in `acme.tools`).
+    pub fn publisher(&self) -> Option<&str> {
+        self.id.split_once('.').map(|(p, _)| p)
+    }
+
+    /// Whether `cap` is declared (required or optional).
+    pub fn declares(&self, cap: &Capability) -> bool {
+        self.capabilities.all().any(|c| c.covers(cap))
+    }
+}
+
+impl Manifest {
+    /// Its marketplace categories, in [`CATEGORIES`] order: the first
+    /// [`MAX_CATEGORIES`] declared that this IDE knows; without any, those its
+    /// contributions imply (themes, icon themes, languages), else `other`.
+    pub fn categories(&self) -> Vec<String> {
+        let pick = |f: &dyn Fn(&str) -> bool| CATEGORIES.iter().filter(|c| f(c)).map(|c| c.to_string()).collect();
+        let mut known: Vec<&str> = Vec::new();
+        for d in &self.declared_categories {
+            if CATEGORIES.contains(&d.as_str()) && !known.contains(&d.as_str()) && known.len() < MAX_CATEGORIES {
+                known.push(d);
+            }
+        }
+        let mut out: Vec<String> = pick(&|c| known.contains(&c));
+        if out.is_empty() {
+            out = pick(&|c| match c {
+                "themes" => self.contributes.contains_key("themes"),
+                "icon-themes" => self.contributes.contains_key("iconThemes"),
+                "languages" => self.contributes.contains_key("languages"),
+                _ => false,
+            });
+        }
+        if out.is_empty() {
+            out.push("other".into());
+        }
+        out
+    }
+
+    /// Declared categories this IDE doesn't know (ignored).
+    pub fn unknown_categories(&self) -> Vec<&str> {
+        self.declared_categories.iter().map(String::as_str).filter(|c| !CATEGORIES.contains(c)).collect()
+    }
+}
+
+/// Whether this host can load a plugin written for `engine`.
+pub fn engine_compatible(engine: &str, legacy: bool) -> bool {
+    if legacy {
+        return engine == LEGACY_API || engine.strip_prefix(LEGACY_API).is_some_and(|rest| rest.starts_with('.'));
+    }
+    let Ok(req) = semver::VersionReq::parse(engine) else { return false };
+    let host = semver::Version::parse(ENGINE_VERSION).expect("valid engine version");
+    req.matches(&host)
+}
+
+/// Segments of `[a-z0-9][a-z0-9_-]*` joined by `.` (an optional publisher
+/// namespace first), at most 64 chars.
+pub fn validate_plugin_id(id: &str) -> Result<(), String> {
+    let ok = id.len() <= 64 && !id.is_empty() && id.split('.').all(segment_ok);
+    if ok {
+        Ok(())
+    } else {
+        Err(format!(
+            "invalid plugin id {id:?}: use a-z, 0-9, '-', '_' in '.'-separated parts (e.g. acme.tools), max 64"
+        ))
+    }
+}
+
+/// `[a-z0-9][a-z0-9._-]*`, at most 64 chars (commands, themes, views…).
+pub fn validate_item_id(id: &str, what: &str) -> Result<(), String> {
+    let ok_first = id.chars().next().is_some_and(|c| c.is_ascii_lowercase() || c.is_ascii_digit());
+    let ok_rest = id.chars().all(|c| c.is_ascii_lowercase() || c.is_ascii_digit() || matches!(c, '-' | '_' | '.'));
+    if ok_first && ok_rest && id.len() <= 64 {
+        Ok(())
+    } else {
+        Err(format!("invalid {what} {id:?}: use a-z, 0-9, '.', '-', '_', starting with a letter or digit (max 64)"))
+    }
+}
+
+/// Extension point ids: `camelCase` or `kebab-case` words, dots allowed (`iconThemes`, `menus`).
+pub fn validate_point_id(id: &str) -> Result<(), String> {
+    let ok = !id.is_empty()
+        && id.len() <= 64
+        && id.starts_with(|c: char| c.is_ascii_lowercase())
+        && id.chars().all(|c| c.is_ascii_alphanumeric() || matches!(c, '-' | '.'));
+    if ok { Ok(()) } else { Err(format!("invalid contribution point {id:?}")) }
+}
+
+fn segment_ok(s: &str) -> bool {
+    s.chars().next().is_some_and(|c| c.is_ascii_lowercase() || c.is_ascii_digit())
+        && s.chars().all(|c| c.is_ascii_lowercase() || c.is_ascii_digit() || c == '-' || c == '_')
+}
+
+/// Package paths must stay inside the package directory.
+pub fn check_relative(path: &Path, what: &str) -> Result<(), String> {
+    let ok = !path.as_os_str().is_empty() && path.components().all(|c| matches!(c, Component::Normal(_)));
+    if ok { Ok(()) } else { Err(format!("{what} {:?} must be a relative path inside the plugin", path.display())) }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    const FULL: &str = r#"
+        id = "acme.rust-tools"
+        name = "Rust Tools"
+        version = "1.2.0"
+        engines.openidea = "^1.0"
+        wasm = "plugin.wasm"
+        activation = ["on-language:rust", "on-command:check", "on-schedule:300"]
+
+        [capabilities]
+        required = ["project.read", "editor.write"]
+        optional = ["net:crates.io", "process:cargo"]
+
+        [[contributes.commands]]
+        id = "check"
+        title = "%check.title%"
+
+        [[contributes.menus]]
+        menu = "editor.context"
+        command = "check"
+        when = "editorLang == rust"
+
+        [contributes.settings]
+        schema = "settings.schema.json"
+    "#;
+
+    #[test]
+    fn event_activation() {
+        assert_eq!(ActivationEvent::parse("on-event:file-saved"), Ok(ActivationEvent::Event("file-saved".into())));
+        assert_eq!(ActivationEvent::Event("vcs-changed".into()).to_string(), "on-event:vcs-changed");
+        let err = ActivationEvent::parse("on-event:keystroke").unwrap_err();
+        assert!(err.contains("unknown event kind") && err.contains("action-performed"), "{err}");
+        assert!(ActivationEvent::parse("on-event:scheduled").is_err(), "declared with on-schedule");
+    }
+
+    #[test]
+    fn categories_are_declared_or_implied() {
+        let head = "id = \"acme.x\"\nname = \"X\"\nversion = \"1.0.0\"\nengines.openidea = \"^1.0\"\n";
+        let m = |rest: &str| Manifest::parse(&format!("{head}{rest}"));
+        // Declared, in the catalogue's order; unknown ones (a newer IDE's) are ignored.
+        let declared = m("categories = [\"tools\", \"vcs\", \"robots\"]\n").unwrap();
+        assert_eq!(declared.categories(), ["vcs", "tools"]);
+        assert_eq!(declared.unknown_categories(), ["robots"]);
+        // None declared: implied by the contributions, else `other`.
+        let theme = m("[[contributes.themes]]\nid = \"t\"\n[[contributes.languages]]\nid = \"l\"\n").unwrap();
+        assert_eq!(theme.categories(), ["languages", "themes"]);
+        let declared_wins = m("categories = [\"tools\"]\n[[contributes.languages]]\nid = \"l\"\n").unwrap();
+        assert_eq!(declared_wins.categories(), ["tools"]);
+        assert_eq!(m("").unwrap().categories(), ["other"]);
+        // At most three: the first ones declared.
+        let many = m("categories = [\"vcs\", \"ai\", \"vcs\", \"tools\", \"themes\"]\n").unwrap();
+        assert_eq!(many.categories(), ["vcs", "ai", "tools"]);
+        assert!(m("categories = [\"Bad Name\"]\n").is_err());
+    }
+
+    #[test]
+    fn parses_the_02_format() {
+        let m = Manifest::parse(FULL).unwrap();
+        assert_eq!(m.publisher(), Some("acme"));
+        assert!(!m.legacy);
+        assert_eq!(m.activation.len(), 3);
+        assert_eq!(m.activation[2], ActivationEvent::Schedule(300));
+        assert_eq!(m.capabilities.required, vec![Capability::ProjectRead, Capability::EditorWrite]);
+        assert!(m.capabilities.is_optional(&Capability::Process("cargo".into())));
+        assert_eq!(m.declarations("commands").len(), 1);
+        assert_eq!(m.declarations("settings").len(), 1, "a single table is one declaration");
+        assert!(m.declarations("nope").is_empty());
+        let counts: Vec<_> = m.declaration_counts();
+        assert!(counts.contains(&("menus".into(), 1)));
+    }
+
+    #[test]
+    fn parses_the_01_format() {
+        let m = Manifest::parse(
+            "id = \"hello\"\nname = \"Hello\"\nversion = \"0.1.0\"\nopenidea-api = \"0.1\"\nwasm = \"dist/plugin.wasm\"\n\
+             permissions = [\"project-read\", \"editor-write\"]\n[[contributes.commands]]\nid = \"x\"\ntitle = \"X\"",
+        )
+        .unwrap();
+        assert!(m.legacy);
+        assert_eq!(m.capabilities.required, vec![Capability::ProjectRead, Capability::EditorWrite]);
+        assert_eq!(m.activation, vec![ActivationEvent::StartupFinished]);
+        assert_eq!(m.publisher(), None);
+    }
+
+    fn err(src: &str) -> String {
+        Manifest::parse(src).unwrap_err()
+    }
+
+    #[test]
+    fn rejects_invalid_manifests() {
+        let base = |extra: &str| format!("id = \"ok\"\nname = \"N\"\nversion = \"1.0.0\"\n{extra}");
+        assert!(err(&base("")).contains("engines.openidea"));
+        assert!(err(&base("engines.openidea = \"^0.3\"")).contains("does not match"));
+        assert!(err(&base("engines.openidea = \"^2\"")).contains("does not match"));
+        assert!(err(&base("engines.openidea = \"^0.2\"")).contains("does not match"));
+        assert!(err(&base("openidea-api = \"0.2\"")).contains("unsupported"));
+        assert!(err(&base("engines.openidea = \"^1.0\"\npermissions = [\"project-read\"]")).contains("0.1 format"));
+        assert!(
+            err(&base("engines.openidea = \"^1.0\"\n[capabilities]\nrequired = [\"network\"]")).contains("unknown")
+        );
+        assert!(err(&base("engines.openidea = \"^1.0\"\nwasm = \"../x.wasm\"")).contains("relative path"));
+        assert!(err(&base("engines.openidea = \"^1.0\"\nactivation = [\"on-command:x\"]")).contains("needs `wasm`"));
+        assert!(
+            err(&base("engines.openidea = \"^1.0\"\nwasm = \"p.wasm\"\nactivation = [\"on-boot\"]"))
+                .contains("unknown")
+        );
+        assert!(
+            err(&base("engines.openidea = \"^1.0\"\nwasm = \"p.wasm\"\nactivation = [\"on-schedule:5\"]"))
+                .contains("60 seconds")
+        );
+        assert!(err(&base("engines.openidea = \"^1.0\"\nbogus = 1")).contains("unknown field"));
+        assert!(err(&base("engines.openidea = \"^1.0\"\ncontributes.commands = 3")).contains("table"));
+        assert!(
+            err("id = \"Bad\"\nname = \"N\"\nversion = \"1.0.0\"\nengines.openidea = \"^1.0\"").contains("plugin id")
+        );
+        assert!(
+            err("id = \"a..b\"\nname = \"N\"\nversion = \"1.0.0\"\nengines.openidea = \"^1.0\"").contains("plugin id")
+        );
+        assert!(err("id = \"ok\"\nname = \"N\"\nversion = \"1.0\"\nengines.openidea = \"^1.0\"").contains("version"));
+    }
+
+    #[test]
+    fn ids() {
+        assert!(validate_plugin_id("openidea.material-icons").is_ok());
+        assert!(validate_plugin_id("hello_2").is_ok());
+        assert!(validate_plugin_id(".x").is_err());
+        assert!(validate_item_id("word-count.v2_x", "command id").is_ok());
+        assert!(validate_item_id("-x", "command id").is_err());
+        assert!(validate_point_id("iconThemes").is_ok());
+        assert!(validate_point_id("Icon").is_err());
+        assert!(engine_compatible("1.0", false));
+        assert!(engine_compatible(">=1.0, <2", false));
+        assert!(!engine_compatible("^0.2", false), "0.x components don't run on 1.0");
+        assert!(engine_compatible("0.1.3", true));
+        assert!(!engine_compatible("0.10", true));
+    }
+}
@@ -0,0 +1,955 @@
+//! Plugin distribution: the package file, its
+//! signature, and the static marketplace index.
+//!
+//! - **Package** (`<id>-<version>.oiplugin`): a zip of the manifest, the files
+//!   its declarations reference, the component and licence files, plus
+//!   [`SIGNATURE_FILE`] when signed.
+//! - **Signature**: Ed25519 over `openidea-plugin/1\n<id>\n<version>\n<digest>`,
+//!   `digest` being [`package_digest`] of the unpacked files. A signature
+//!   proves who published the bytes; whether to trust that publisher is the
+//!   index's call.
+//! - **Index** (`index.json`): the publishers and their keys (the trust root),
+//!   the published plugin versions, and revocations. A publisher owns the id
+//!   prefix `<publisher>.`; a revoked key invalidates everything it signed, a
+//!   revoked plugin version is disabled where it is installed. A plugin may be
+//!   listed in several versions, each with the plugin API it needs: the IDE
+//!   offers the newest one it can load.
+//! - **Key continuity**: an installed plugin updates silently only to a
+//!   package signed with the same key, or with a key the installed one
+//!   endorsed ([`Endorsement`], a publisher rotating keys); any other signer
+//!   is the user's call. An IDE can pin a publisher to keys it was built with
+//!   ([`Index::pin_publisher`]): the index then can't replace them.
+//! - **Format**: fields are only ever added (IDEs ignore those they don't
+//!   know); `format` grows only for changes older IDEs can't read, and they
+//!   still apply such an index's revocations ([`Index::parse`]).
+
+use crate::MANIFEST_FILE;
+use base64::Engine as _;
+use ed25519_dalek::{Signature, Signer, SigningKey, VerifyingKey};
+use serde::{Deserialize, Serialize};
+use std::io::{Read, Write};
+use std::path::{Component, Path, PathBuf};
+
+pub const SIGNATURE_FILE: &str = "SIGNATURE.json";
+pub const PACKAGE_EXTENSION: &str = "oiplugin";
+pub const INDEX_FORMAT: u32 = 1;
+/// Limits when unpacking an untrusted package.
+const MAX_ENTRIES: usize = 10_000;
+const MAX_TOTAL: u64 = 512 << 20;
+
+const B64: base64::engine::GeneralPurpose = base64::engine::general_purpose::STANDARD;
+
+/// Content digest of a package: the manifest plus `files` (relative paths).
+pub fn package_digest(dir: &Path, files: &[PathBuf]) -> std::io::Result<String> {
+    let mut all = files.to_vec();
+    all.push(PathBuf::from(MANIFEST_FILE));
+    crate::ledger::package_hash(dir, &all)
+}
+
+fn signed_message(id: &str, version: &str, digest: &str) -> Vec<u8> {
+    format!("openidea-plugin/1\n{id}\n{version}\n{digest}").into_bytes()
+}
+
+fn endorsement_message(publisher: &str, key: &str) -> Vec<u8> {
+    format!("openidea-key/1\n{publisher}\n{key}").into_bytes()
+}
+
+/// Whether `signature` (base64) is `key`'s (base64) Ed25519 signature of
+/// `message`; malformed keys and signatures are errors.
+fn verify_ed25519(key: &str, message: &[u8], signature: &str) -> Result<bool, String> {
+    let key: [u8; 32] = B64
+        .decode(key)
+        .ok()
+        .and_then(|b| b.try_into().ok())
+        .ok_or_else(|| "signature: malformed public key".to_owned())?;
+    let key = VerifyingKey::from_bytes(&key).map_err(|_| "signature: invalid public key".to_owned())?;
+    let sig: [u8; 64] =
+        B64.decode(signature).ok().and_then(|b| b.try_into().ok()).ok_or_else(|| "signature: malformed".to_owned())?;
+    Ok(key.verify_strict(message, &Signature::from_bytes(&sig)).is_ok())
+}
+
+/// `SIGNATURE.json` of a signed package.
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct PackageSignature {
+    pub publisher: String,
+    /// Ed25519 public key, base64.
+    pub key: String,
+    /// Ed25519 signature, base64.
+    pub signature: String,
+}
+
+/// A publisher's key pair (the 32-byte seed, base64, in a file only the publisher has).
+pub struct PublisherKey(SigningKey);
+
+impl PublisherKey {
+    pub fn from_seed(seed: [u8; 32]) -> Self {
+        Self(SigningKey::from_bytes(&seed))
+    }
+
+    /// The seed as written by `openidea-plugin keygen`.
+    pub fn from_base64(text: &str) -> Result<Self, String> {
+        let bytes = B64.decode(text.trim()).map_err(|e| format!("key file: {e}"))?;
+        let seed: [u8; 32] = bytes.try_into().map_err(|_| "key file: expected a 32-byte key".to_owned())?;
+        Ok(Self::from_seed(seed))
+    }
+
+    pub fn seed_base64(&self) -> String {
+        B64.encode(self.0.to_bytes())
+    }
+
+    pub fn public_base64(&self) -> String {
+        B64.encode(self.0.verifying_key().to_bytes())
+    }
+
+    /// Vouches for `publisher`'s new key `key` (base64), the one that follows this one.
+    pub fn endorse(&self, publisher: &str, key: &str) -> Endorsement {
+        let sig = self.0.sign(&endorsement_message(publisher, key));
+        Endorsement { key: self.public_base64(), signature: B64.encode(sig.to_bytes()) }
+    }
+
+    pub fn sign(&self, publisher: &str, id: &str, version: &str, digest: &str) -> PackageSignature {
+        let sig = self.0.sign(&signed_message(id, version, digest));
+        PackageSignature {
+            publisher: publisher.into(),
+            key: self.public_base64(),
+            signature: B64.encode(sig.to_bytes()),
+        }
+    }
+}
+
+impl PackageSignature {
+    /// Whether the signature is valid for `id`, `version` and `digest` (the
+    /// key's validity is checked against an [`Index`]).
+    pub fn check(&self, id: &str, version: &str, digest: &str) -> Result<(), String> {
+        if verify_ed25519(&self.key, &signed_message(id, version, digest), &self.signature)? {
+            Ok(())
+        } else {
+            Err("the signature does not match the package (it was changed after signing)".to_owned())
+        }
+    }
+}
+
+/// Writes the package `out` from `dir`: the manifest, `files`, and the signature if any.
+pub fn pack(dir: &Path, files: &[PathBuf], out: &Path, signature: Option<&PackageSignature>) -> Result<(), String> {
+    let io = |e: std::io::Error| e.to_string();
+    let file = std::fs::File::create(out).map_err(io)?;
+    let mut zip = zip::ZipWriter::new(file);
+    let options = zip::write::SimpleFileOptions::default().compression_method(zip::CompressionMethod::Deflated);
+    let mut names: Vec<PathBuf> = std::iter::once(PathBuf::from(MANIFEST_FILE)).chain(files.iter().cloned()).collect();
+    names.sort();
+    names.dedup();
+    for rel in names {
+        let name = rel.to_str().ok_or("non UTF-8 file name")?.replace('\\', "/");
+        zip.start_file(name, options).map_err(|e| e.to_string())?;
+        let bytes = std::fs::read(dir.join(&rel)).map_err(|e| format!("{}: {e}", rel.display()))?;
+        zip.write_all(&bytes).map_err(io)?;
+    }
+    if let Some(sig) = signature {
+        zip.start_file(SIGNATURE_FILE, options).map_err(|e| e.to_string())?;
+        zip.write_all(serde_json::to_string_pretty(sig).map_err(|e| e.to_string())?.as_bytes()).map_err(io)?;
+    }
+    zip.finish().map_err(|e| e.to_string())?;
+    Ok(())
+}
+
+/// What [`unpack`] wrote.
+#[derive(Debug)]
+pub struct Unpacked {
+    /// Every file but the manifest and the signature, relative.
+    pub files: Vec<PathBuf>,
+    pub signature: Option<PackageSignature>,
+}
+
+/// `name` as a relative path that stays inside the package.
+fn safe_path(name: &str) -> Option<PathBuf> {
+    let p = Path::new(name);
+    (!name.is_empty() && p.components().all(|c| matches!(c, Component::Normal(_)))).then(|| p.to_path_buf())
+}
+
+/// Archiver metadata at the top of an archive, not part of a package
+/// (`__MACOSX/…`, `.DS_Store`, AppleDouble `._…` files).
+fn archiver_metadata(name: &str) -> bool {
+    let top = name.split('/').next().unwrap_or_default();
+    top == "__MACOSX" || top == ".DS_Store" || (top.starts_with("._") && top.len() > 2)
+}
+
+/// Where the package is inside an archive: at its root (`.oiplugin`, or a zip
+/// of the package's contents) or in its only folder (a zip of the package
+/// folder). `None` when neither holds a manifest.
+fn package_prefix(names: &[String]) -> Option<String> {
+    if names.iter().any(|n| n == MANIFEST_FILE) {
+        return Some(String::new());
+    }
+    let mut tops = names.iter().filter(|n| !archiver_metadata(n)).map(|n| n.split('/').next().unwrap_or_default());
+    let top = tops.next()?;
+    if tops.any(|t| t != top) {
+        return None;
+    }
+    let prefix = format!("{top}/");
+    names.iter().any(|n| *n == format!("{prefix}{MANIFEST_FILE}")).then_some(prefix)
+}
+
+/// Extracts the package `archive` (an `.oiplugin`, or a `.zip` of a package
+/// folder or of its contents) into the empty directory `dest`, refusing
+/// paths leaving it, links, and oversized contents.
+pub fn unpack(archive: &Path, dest: &Path) -> Result<Unpacked, String> {
+    let file = std::fs::File::open(archive).map_err(|e| format!("{}: {e}", archive.display()))?;
+    let mut zip =
+        zip::ZipArchive::new(file).map_err(|e| format!("{}: not a plugin package ({e})", archive.display()))?;
+    if zip.len() > MAX_ENTRIES {
+        return Err(format!("more than {MAX_ENTRIES} files"));
+    }
+    let mut names = Vec::with_capacity(zip.len());
+    for i in 0..zip.len() {
+        let entry = zip.by_index(i).map_err(|e| e.to_string())?;
+        if !entry.is_dir() {
+            names.push(entry.name().map_err(|e| e.to_string())?.into_owned());
+        }
+    }
+    // An IntelliJ plugin or any other zip: say what is missing rather than fail later.
+    let prefix = package_prefix(&names).ok_or_else(|| {
+        format!("{} is not an OpenIDEA plugin: no {MANIFEST_FILE} at its root or in its only folder", archive.display())
+    })?;
+    std::fs::create_dir_all(dest).map_err(|e| e.to_string())?;
+    let (mut files, mut signature, mut total, mut manifest) = (Vec::new(), None, 0u64, false);
+    for i in 0..zip.len() {
+        let mut entry = zip.by_index(i).map_err(|e| e.to_string())?;
+        if entry.is_dir() {
+            continue;
+        }
+        let full = entry.name().map_err(|e| e.to_string())?.into_owned();
+        // Outside the package folder there is only archiver metadata (`package_prefix` checked).
+        let Some(name) = full.strip_prefix(&prefix).map(str::to_owned) else { continue };
+        if archiver_metadata(&name) {
+            continue;
+        }
+        if entry.is_symlink() {
+            return Err(format!("{full}: links are not allowed in packages"));
+        }
+        let rel = safe_path(&name).ok_or_else(|| format!("invalid path {full:?} in package"))?;
+        let mut bytes = Vec::new();
+        entry.by_ref().take(MAX_TOTAL - total + 1).read_to_end(&mut bytes).map_err(|e| e.to_string())?;
+        total += bytes.len() as u64;
+        if total > MAX_TOTAL {
+            return Err(format!("the package unpacks to more than {} MiB", MAX_TOTAL >> 20));
+        }
+        if rel == Path::new(SIGNATURE_FILE) {
+            signature = Some(serde_json::from_slice(&bytes).map_err(|e| format!("{SIGNATURE_FILE}: {e}"))?);
+            continue;
+        }
+        let to = dest.join(&rel);
+        if let Some(parent) = to.parent() {
+            std::fs::create_dir_all(parent).map_err(|e| e.to_string())?;
+        }
+        std::fs::write(&to, bytes).map_err(|e| e.to_string())?;
+        if rel == Path::new(MANIFEST_FILE) {
+            manifest = true;
+        } else {
+            files.push(rel);
+        }
+    }
+    if !manifest {
+        return Err(format!("the package has no {MANIFEST_FILE}"));
+    }
+    files.sort();
+    Ok(Unpacked { files, signature })
+}
+
+// ---- index -------------------------------------------------------------------
+
+#[derive(Clone, Debug, Default, PartialEq, Eq, Serialize, Deserialize, specta::Type)]
+#[serde(rename_all = "camelCase")]
+pub struct Index {
+    pub format: u32,
+    #[serde(default)]
+    pub publishers: Vec<Publisher>,
+    #[serde(default)]
+    pub plugins: Vec<IndexEntry>,
+    #[serde(default)]
+    pub revoked: Vec<Revocation>,
+    /// The marketplace moved: its index is at this URL (relative to this
+    /// one, or absolute), and the IDE reads that one instead.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub moved: Option<String>,
+}
+
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize, specta::Type)]
+#[serde(rename_all = "camelCase")]
+pub struct Publisher {
+    /// Owns plugin ids `<id>.…`.
+    pub id: String,
+    pub name: String,
+    pub keys: Vec<KeyEntry>,
+}
+
+#[derive(Clone, Debug, Default, PartialEq, Eq, Serialize, Deserialize, specta::Type)]
+#[serde(rename_all = "camelCase")]
+pub struct KeyEntry {
+    /// Ed25519 public key, base64.
+    pub key: String,
+    /// Packages signed with it are no longer trusted.
+    #[serde(default)]
+    pub revoked: bool,
+    /// The publisher's earlier key vouching for this one.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub endorsement: Option<Endorsement>,
+}
+
+impl KeyEntry {
+    pub fn new(key: String) -> Self {
+        Self { key, ..Self::default() }
+    }
+}
+
+/// A publisher's earlier key vouching for a newer one: plugins installed from
+/// packages signed with the earlier key update to ones signed with the newer
+/// key without asking the user.
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize, specta::Type)]
+#[serde(rename_all = "camelCase")]
+pub struct Endorsement {
+    /// The endorsing key, base64.
+    pub key: String,
+    /// Its Ed25519 signature of `openidea-key/1\n<publisher>\n<endorsed key>`, base64.
+    pub signature: String,
+}
+
+/// A published plugin version.
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize, specta::Type)]
+#[serde(rename_all = "camelCase")]
+pub struct IndexEntry {
+    pub id: String,
+    pub name: String,
+    pub version: String,
+    #[serde(default)]
+    pub description: String,
+    #[serde(default)]
+    pub authors: Vec<String>,
+    pub publisher: String,
+    /// The package, relative to the index (or an absolute URL).
+    pub download: String,
+    /// [`package_digest`] of its contents.
+    pub digest: String,
+    #[serde(default)]
+    pub capabilities: Vec<String>,
+    /// The plugin API versions it loads in (a semver requirement): its
+    /// manifest's `engines.openidea` and the API its component was built for.
+    /// Required: an entry without one is offered to no IDE.
+    #[serde(default)]
+    pub engine: String,
+    /// Marketplace categories (`CATEGORIES`); an IDE ignores those it doesn't know.
+    #[serde(default)]
+    pub categories: Vec<String>,
+}
+
+impl IndexEntry {
+    /// Whether this IDE can load the version.
+    pub fn compatible(&self) -> bool {
+        crate::engine_compatible(&self.engine, false)
+    }
+
+    fn semver(&self) -> Option<semver::Version> {
+        semver::Version::parse(&self.version).ok()
+    }
+}
+
+/// `engines.openidea` of a manifest narrowed to the API its component was built
+/// for (`major.minor`, if it has code): the requirement an index lists.
+pub fn engine_requirement(manifest_engine: &str, built_for: Option<&semver::Version>) -> String {
+    match built_for {
+        Some(v) => format!("{manifest_engine}, ^{}.{}", v.major, v.minor),
+        None => manifest_engine.to_owned(),
+    }
+}
+
+/// A plugin (all versions when `versions` is empty) that must not run.
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize, specta::Type)]
+#[serde(rename_all = "camelCase")]
+pub struct Revocation {
+    pub id: String,
+    #[serde(default)]
+    pub versions: Vec<String>,
+    pub reason: String,
+}
+
+impl Index {
+    /// Parses an index. One in a newer format keeps what must reach every IDE —
+    /// revocations, publisher keys (revoked ones) and `moved` — and lists no
+    /// plugins ([`Index::is_newer`]): the IDE needs updating to install from it.
+    pub fn parse(text: &str) -> Result<Self, String> {
+        let value: serde_json::Value = serde_json::from_str(text).map_err(|e| format!("index: {e}"))?;
+        let format = value.get("format").and_then(serde_json::Value::as_u64).ok_or("index: `format` is missing")?;
+        if format == u64::from(INDEX_FORMAT) {
+            return serde_json::from_value(value).map_err(|e| format!("index: {e}"));
+        }
+        if format < u64::from(INDEX_FORMAT) {
+            return Err(format!("index format {format} is not supported (this IDE reads {INDEX_FORMAT})"));
+        }
+        fn each<T: serde::de::DeserializeOwned>(value: &serde_json::Value, field: &str) -> Vec<T> {
+            let items = value.get(field).and_then(serde_json::Value::as_array);
+            items.into_iter().flatten().filter_map(|v| serde_json::from_value(v.clone()).ok()).collect()
+        }
+        Ok(Index {
+            format: u32::try_from(format).unwrap_or(u32::MAX),
+            publishers: each(&value, "publishers"),
+            plugins: Vec::new(),
+            revoked: each(&value, "revoked"),
+            moved: value.get("moved").and_then(serde_json::Value::as_str).map(str::to_owned),
+        })
+    }
+
+    /// Written in a format newer than this IDE reads: it lists no plugins.
+    pub fn is_newer(&self) -> bool {
+        self.format > INDEX_FORMAT
+    }
+
+    /// The version of each plugin to offer, and whether this IDE can load it:
+    /// the newest it can load, else the newest. Revoked versions are skipped;
+    /// plugins come in the order they are first listed.
+    pub fn offered(&self) -> Vec<(&IndexEntry, bool)> {
+        let mut ids: Vec<&str> = Vec::new();
+        for e in &self.plugins {
+            if !ids.contains(&e.id.as_str()) {
+                ids.push(&e.id);
+            }
+        }
+        ids.into_iter()
+            .filter_map(|id| {
+                let versions: Vec<&IndexEntry> =
+                    self.plugins.iter().filter(|e| e.id == id && self.revocation(id, &e.version).is_none()).collect();
+                let newest = |loadable: bool| {
+                    versions.iter().copied().filter(|e| !loadable || e.compatible()).max_by_key(|e| e.semver())
+                };
+                newest(true).map(|e| (e, true)).or_else(|| newest(false).map(|e| (e, false)))
+            })
+            .collect()
+    }
+
+    /// Drops the versions no IDE would pick: revoked ones, and of each plugin
+    /// all but the newest version per API requirement.
+    pub fn prune_versions(&mut self) {
+        let plugins = std::mem::take(&mut self.plugins);
+        let mut kept: Vec<IndexEntry> = Vec::new();
+        for e in plugins.into_iter().filter(|e| self.revocation(&e.id, &e.version).is_none()) {
+            match kept.iter_mut().find(|k| k.id == e.id && k.engine == e.engine) {
+                Some(k) if e.semver() > k.semver() => *k = e,
+                Some(_) => {}
+                None => kept.push(e),
+            }
+        }
+        self.plugins = kept;
+    }
+
+    /// The revocation that applies to `id` at `version`.
+    pub fn revocation(&self, id: &str, version: &str) -> Option<&Revocation> {
+        self.revoked.iter().find(|r| r.id == id && (r.versions.is_empty() || r.versions.iter().any(|v| v == version)))
+    }
+
+    /// Whether `key` (base64) belongs to a publisher and was revoked.
+    pub fn key_revoked(&self, key: &str) -> bool {
+        self.publishers.iter().flat_map(|p| &p.keys).any(|k| k.key == key && k.revoked)
+    }
+
+    /// The trusted publisher of a signed package: the signature is valid, its
+    /// key is one of the publisher's and not revoked, and the publisher owns
+    /// the plugin's id prefix.
+    pub fn verify(&self, sig: &PackageSignature, id: &str, version: &str, digest: &str) -> Result<String, String> {
+        let publisher = self
+            .publishers
+            .iter()
+            .find(|p| p.id == sig.publisher)
+            .ok_or_else(|| format!("unknown publisher {:?}", sig.publisher))?;
+        let key = publisher
+            .keys
+            .iter()
+            .find(|k| k.key == sig.key)
+            .ok_or_else(|| format!("the key is not one of {}'s", publisher.name))?;
+        if key.revoked {
+            return Err(format!("{}'s signing key was revoked", publisher.name));
+        }
+        if !id.starts_with(&format!("{}.", publisher.id)) {
+            return Err(format!("{} may only publish plugins named {}.*", publisher.name, publisher.id));
+        }
+        sig.check(id, version, digest)?;
+        Ok(publisher.id.clone())
+    }
+
+    /// Whether `to` is `from`, or a key of `publisher` that `from` endorsed,
+    /// directly or through keys it endorsed. Endorsements by revoked keys don't
+    /// count: whoever stole a key could vouch for their own.
+    pub fn succeeds(&self, publisher: &str, from: &str, to: &str) -> bool {
+        let keys = self.publishers.iter().find(|p| p.id == publisher).map_or(&[][..], |p| &p.keys[..]);
+        let mut key = to;
+        // Each step moves to an earlier key; more steps than keys is a loop.
+        for _ in 0..=keys.len() {
+            if key == from {
+                return true;
+            }
+            let Some(e) = keys.iter().find(|k| k.key == key).and_then(|k| k.endorsement.as_ref()) else {
+                return false;
+            };
+            let endorser_valid = keys.iter().any(|k| k.key == e.key && !k.revoked);
+            if !endorser_valid || verify_ed25519(&e.key, &endorsement_message(publisher, key), &e.signature) != Ok(true)
+            {
+                return false;
+            }
+            key = &e.key;
+        }
+        false
+    }
+
+    /// Makes `roots` (base64) the keys `publisher` signs with, whatever this
+    /// index says: another key it lists stays only when a root endorsed it (a
+    /// rotation the roots vouched for). Revocations of the keys are kept.
+    pub fn pin_publisher(&mut self, publisher: &str, name: &str, roots: &[String]) {
+        if roots.is_empty() {
+            return;
+        }
+        let i = match self.publishers.iter().position(|p| p.id == publisher) {
+            Some(i) => i,
+            None => {
+                self.publishers.push(Publisher { id: publisher.into(), name: name.into(), keys: Vec::new() });
+                self.publishers.len() - 1
+            }
+        };
+        for root in roots {
+            if !self.publishers[i].keys.iter().any(|k| &k.key == root) {
+                self.publishers[i].keys.push(KeyEntry::new(root.clone()));
+            }
+        }
+        let keys = self.publishers[i].keys.clone();
+        let trusted = keys
+            .into_iter()
+            .filter(|k| roots.iter().any(|r| self.succeeds(publisher, r, &k.key)))
+            .map(|k| if roots.contains(&k.key) { KeyEntry { endorsement: None, ..k } } else { k })
+            .collect();
+        self.publishers[i].keys = trusted;
+    }
+
+    /// Replaces what this index lists for every publisher but `keep` with what
+    /// `other` lists: its publishers, their plugins and their revocations
+    /// (`other`'s downloads should already be absolute). `other` may only
+    /// speak for its own publishers, and none of them may be in `keep`.
+    pub fn include(&mut self, other: Index, keep: &[&str]) -> Result<(), String> {
+        let mut theirs: Vec<&str> = Vec::new();
+        for p in &other.publishers {
+            if !publisher_id_ok(&p.id) {
+                return Err(format!("invalid publisher id {:?}: use a-z, 0-9, '-' and '_'", p.id));
+            }
+            if keep.contains(&p.id.as_str()) {
+                return Err(format!("may not list publisher {:?}", p.id));
+            }
+            if theirs.contains(&p.id.as_str()) {
+                return Err(format!("publisher {:?} is listed twice", p.id));
+            }
+            theirs.push(&p.id);
+        }
+        let owned_by = |id: &str| theirs.iter().any(|p| owns(p, id));
+        for e in &other.plugins {
+            if !theirs.contains(&e.publisher.as_str()) || !owns(&e.publisher, &e.id) {
+                return Err(format!("{}: not a plugin of publisher {:?}", e.id, e.publisher));
+            }
+            if semver::VersionReq::parse(&e.engine).is_err() {
+                return Err(format!("{} {}: `engine` must be the plugin API it needs", e.id, e.version));
+            }
+        }
+        if let Some(r) = other.revoked.iter().find(|r| !owned_by(&r.id)) {
+            return Err(format!("{}: revoked by an index that doesn't publish it", r.id));
+        }
+        let kept = |id: &str| keep.iter().any(|p| owns(p, id));
+        self.publishers.retain(|p| keep.contains(&p.id.as_str()));
+        self.plugins.retain(|e| keep.contains(&e.publisher.as_str()));
+        self.revoked.retain(|r| kept(&r.id));
+        self.publishers.extend(other.publishers);
+        self.plugins.extend(other.plugins);
+        self.revoked.extend(other.revoked);
+        Ok(())
+    }
+}
+
+/// Whether a package signed `new` (`None`: unsigned) may replace an installed
+/// one signed `installed` without asking the user: signed with the same key,
+/// or with one the installed key endorsed (per `index`). An unsigned installed
+/// copy pins nothing.
+pub fn signer_continues(
+    index: Option<&Index>,
+    installed: Option<&PackageSignature>,
+    new: Option<&PackageSignature>,
+) -> bool {
+    match (installed, new) {
+        (None, _) => true,
+        (Some(_), None) => false,
+        (Some(old), Some(new)) => {
+            old.publisher == new.publisher
+                && (old.key == new.key || index.is_some_and(|i| i.succeeds(&new.publisher, &old.key, &new.key)))
+        }
+    }
+}
+
+/// Whether the plugin `id` is in `publisher`'s namespace.
+fn owns(publisher: &str, id: &str) -> bool {
+    id.strip_prefix(publisher).is_some_and(|rest| rest.starts_with('.'))
+}
+
+/// A publisher id is a single segment of a plugin id.
+pub fn publisher_id_ok(id: &str) -> bool {
+    !id.contains('.') && crate::validate_plugin_id(id).is_ok()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn package(dir: &Path) -> Vec<PathBuf> {
+        std::fs::create_dir_all(dir.join("dist")).unwrap();
+        std::fs::write(dir.join(MANIFEST_FILE), "id = \"acme.tools\"\nversion = \"1.0.0\"").unwrap();
+        std::fs::write(dir.join("dist/plugin.wasm"), b"\0asm").unwrap();
+        vec![PathBuf::from("dist/plugin.wasm")]
+    }
+
+    fn index(key: &PublisherKey) -> Index {
+        Index {
+            format: INDEX_FORMAT,
+            publishers: vec![Publisher {
+                id: "acme".into(),
+                name: "ACME".into(),
+                keys: vec![KeyEntry::new(key.public_base64())],
+            }],
+            plugins: Vec::new(),
+            revoked: vec![Revocation {
+                id: "acme.bad".into(),
+                versions: vec!["1.0.0".into()],
+                reason: "malware".into(),
+            }],
+            moved: None,
+        }
+    }
+
+    #[test]
+    fn signed_packages_round_trip_and_tampering_is_caught() {
+        let tmp = tempfile::tempdir().unwrap();
+        let src = tmp.path().join("src");
+        let files = package(&src);
+        let digest = package_digest(&src, &files).unwrap();
+        let key = PublisherKey::from_seed([7; 32]);
+        let sig = key.sign("acme", "acme.tools", "1.0.0", &digest);
+        let out = tmp.path().join("acme.tools-1.0.0.oiplugin");
+        pack(&src, &files, &out, Some(&sig)).unwrap();
+
+        let dest = tmp.path().join("dest");
+        let unpacked = unpack(&out, &dest).unwrap();
+        assert_eq!(unpacked.files, files);
+        assert_eq!(package_digest(&dest, &unpacked.files).unwrap(), digest);
+        let index = index(&key);
+        assert_eq!(index.verify(unpacked.signature.as_ref().unwrap(), "acme.tools", "1.0.0", &digest).unwrap(), "acme");
+
+        // Changed bytes, another id, someone else's prefix, a revoked key.
+        assert!(index.verify(&sig, "acme.tools", "1.0.0", "0000").is_err());
+        assert!(index.verify(&sig, "acme.tools", "1.0.1", &digest).is_err());
+        let other = PublisherKey::from_seed([9; 32]).sign("acme", "acme.tools", "1.0.0", &digest);
+        assert!(index.verify(&other, "acme.tools", "1.0.0", &digest).unwrap_err().contains("not one of"));
+        let foreign = key.sign("acme", "evil.tools", "1.0.0", &digest);
+        assert!(index.verify(&foreign, "evil.tools", "1.0.0", &digest).unwrap_err().contains("acme.*"));
+        let mut revoked = index.clone();
+        revoked.publishers[0].keys[0].revoked = true;
+        assert!(revoked.verify(&sig, "acme.tools", "1.0.0", &digest).unwrap_err().contains("revoked"));
+        assert!(revoked.key_revoked(&sig.key));
+        assert_eq!(index.revocation("acme.bad", "1.0.0").unwrap().reason, "malware");
+        assert!(index.revocation("acme.bad", "1.0.1").is_none());
+        assert_eq!(PublisherKey::from_base64(&key.seed_base64()).unwrap().public_base64(), key.public_base64());
+    }
+
+    fn entry(id: &str, publisher: &str) -> IndexEntry {
+        IndexEntry {
+            id: id.into(),
+            name: id.into(),
+            version: "1.0.0".into(),
+            description: String::new(),
+            authors: Vec::new(),
+            publisher: publisher.into(),
+            download: format!("https://example.com/{id}.oiplugin"),
+            digest: "d".into(),
+            capabilities: Vec::new(),
+            engine: "^1.0".into(),
+            categories: Vec::new(),
+        }
+    }
+
+    fn version(id: &str, version: &str, engine: &str) -> IndexEntry {
+        IndexEntry { version: version.into(), engine: engine.into(), ..entry(id, "acme") }
+    }
+
+    #[test]
+    fn the_ide_is_offered_the_newest_version_it_can_load() {
+        let host = crate::ENGINE_VERSION;
+        let newer = semver::Version::parse(host).unwrap().major + 1;
+        let mut index = Index {
+            format: INDEX_FORMAT,
+            plugins: vec![
+                version("acme.a", "1.0.0", &format!("^{host}")),
+                version("acme.a", "1.2.0", &format!("^{host}")),
+                version("acme.a", "2.0.0", &format!("^{newer}.0")),
+                version("acme.b", "0.1.0", &format!("^{newer}.0")),
+                version("acme.b", "0.2.0", &format!("^{newer}.1")),
+                version("acme.c", "1.0.0", ""),
+                version("acme.c", "1.1.0", ""),
+            ],
+            revoked: vec![Revocation { id: "acme.c".into(), versions: vec!["1.1.0".into()], reason: "r".into() }],
+            ..Index::default()
+        };
+        let offered = |index: &Index| {
+            index.offered().into_iter().map(|(e, ok)| (e.id.clone(), e.version.clone(), ok)).collect::<Vec<_>>()
+        };
+        let expected = [
+            ("acme.a".to_owned(), "1.2.0".to_owned(), true),
+            ("acme.b".to_owned(), "0.2.0".to_owned(), false),
+            // No `engine`: listed, but no IDE installs it.
+            ("acme.c".to_owned(), "1.0.0".to_owned(), false),
+        ];
+        assert_eq!(offered(&index), expected);
+
+        // Pruning keeps the newest version per requirement, which changes nothing offered.
+        index.prune_versions();
+        let left: Vec<_> = index.plugins.iter().map(|e| format!("{} {}", e.id, e.version)).collect();
+        assert_eq!(left, ["acme.a 1.2.0", "acme.a 2.0.0", "acme.b 0.1.0", "acme.b 0.2.0", "acme.c 1.0.0"]);
+        assert_eq!(offered(&index), expected);
+
+        let built_for = semver::Version::new(1, 3, 0);
+        assert_eq!(engine_requirement("^1.0", Some(&built_for)), "^1.0, ^1.3");
+        assert_eq!(engine_requirement("^1.0", None), "^1.0");
+        assert!(semver::VersionReq::parse(&engine_requirement("^1.0", Some(&built_for))).is_ok());
+    }
+
+    fn publisher(id: &str) -> Publisher {
+        Publisher { id: id.into(), name: id.into(), keys: vec![KeyEntry::new(format!("{id}-key"))] }
+    }
+
+    fn revocation(id: &str) -> Revocation {
+        Revocation { id: id.into(), versions: Vec::new(), reason: "r".into() }
+    }
+
+    #[test]
+    fn including_an_index_replaces_everything_but_the_kept_publishers() {
+        let mut official = Index {
+            format: INDEX_FORMAT,
+            publishers: vec![publisher("openidea"), publisher("gone")],
+            plugins: vec![entry("openidea.a", "openidea"), entry("gone.x", "gone")],
+            revoked: vec![revocation("openidea.old"), revocation("gone.x")],
+            moved: None,
+        };
+        let community = Index {
+            format: INDEX_FORMAT,
+            publishers: vec![publisher("alice")],
+            plugins: vec![entry("alice.arthas", "alice")],
+            revoked: vec![revocation("alice.bad")],
+            moved: None,
+        };
+        official.include(community.clone(), &["openidea"]).unwrap();
+        let ids = |v: &[IndexEntry]| v.iter().map(|e| e.id.clone()).collect::<Vec<_>>();
+        assert_eq!(official.publishers.iter().map(|p| p.id.as_str()).collect::<Vec<_>>(), ["openidea", "alice"]);
+        assert_eq!(ids(&official.plugins), ["openidea.a", "alice.arthas"]);
+        assert_eq!(official.revoked.iter().map(|r| r.id.as_str()).collect::<Vec<_>>(), ["openidea.old", "alice.bad"]);
+
+        // Including again is idempotent.
+        let once = official.clone();
+        official.include(community.clone(), &["openidea"]).unwrap();
+        assert_eq!(official, once);
+    }
+
+    #[test]
+    fn an_included_index_speaks_only_for_its_own_publishers() {
+        let base = Index { format: INDEX_FORMAT, publishers: vec![publisher("openidea")], ..Index::default() };
+        let with = |publishers: Vec<Publisher>, plugins: Vec<IndexEntry>, revoked: Vec<Revocation>| Index {
+            format: INDEX_FORMAT,
+            publishers,
+            plugins,
+            revoked,
+            moved: None,
+        };
+        let cases = [
+            (with(vec![publisher("openidea")], vec![], vec![]), "may not list"),
+            (with(vec![publisher("alice"), publisher("alice")], vec![], vec![]), "listed twice"),
+            (with(vec![publisher("openidea.x")], vec![], vec![]), "invalid publisher"),
+            (with(vec![publisher("alice")], vec![entry("openidea.a", "alice")], vec![]), "not a plugin of"),
+            (with(vec![publisher("alice")], vec![entry("alice.a", "bob")], vec![]), "not a plugin of"),
+            (with(vec![publisher("alice")], vec![entry("alicex.a", "alice")], vec![]), "not a plugin of"),
+            (with(vec![publisher("alice")], vec![], vec![revocation("openidea.a")]), "doesn't publish"),
+            (
+                with(
+                    vec![publisher("alice")],
+                    vec![IndexEntry { engine: String::new(), ..entry("alice.a", "alice") }],
+                    vec![],
+                ),
+                "`engine`",
+            ),
+        ];
+        for (other, error) in cases {
+            let mut index = base.clone();
+            let err = index.include(other, &["openidea"]).unwrap_err();
+            assert!(err.contains(error), "{err}");
+            assert_eq!(index, base);
+        }
+    }
+
+    #[test]
+    fn unpacking_refuses_paths_leaving_the_package() {
+        let tmp = tempfile::tempdir().unwrap();
+        let out = tmp.path().join("evil.oiplugin");
+        let mut zip = zip::ZipWriter::new(std::fs::File::create(&out).unwrap());
+        let o = zip::write::SimpleFileOptions::default();
+        zip.start_file(MANIFEST_FILE, o).unwrap();
+        zip.write_all(b"id = \"x\"").unwrap();
+        zip.start_file("../outside.txt", o).unwrap();
+        zip.write_all(b"x").unwrap();
+        zip.finish().unwrap();
+        let err = unpack(&out, &tmp.path().join("dest")).unwrap_err();
+        assert!(err.contains("invalid path"), "{err}");
+        assert!(!tmp.path().join("outside.txt").exists());
+        assert!(Index::parse(r#"{"format": 2}"#).unwrap().is_newer());
+    }
+
+    fn zip_of(path: &Path, entries: &[(&str, &str)]) {
+        let mut zip = zip::ZipWriter::new(std::fs::File::create(path).unwrap());
+        for (name, body) in entries {
+            zip.start_file(*name, zip::write::SimpleFileOptions::default()).unwrap();
+            zip.write_all(body.as_bytes()).unwrap();
+        }
+        zip.finish().unwrap();
+    }
+
+    #[test]
+    fn a_zip_holds_the_package_at_its_root_or_in_its_only_folder() {
+        let tmp = tempfile::tempdir().unwrap();
+        let manifest = "id = \"acme.tools\"";
+        let at_root = tmp.path().join("root.zip");
+        zip_of(&at_root, &[(MANIFEST_FILE, manifest), ("dist/plugin.wasm", "w"), (".DS_Store", "x")]);
+        let got = unpack(&at_root, &tmp.path().join("a")).unwrap();
+        assert_eq!(got.files, [PathBuf::from("dist/plugin.wasm")]);
+
+        // What zipping the folder in Finder makes: the folder plus `__MACOSX`.
+        let folder = tmp.path().join("folder.zip");
+        zip_of(
+            &folder,
+            &[
+                ("acme-tools/plugin.toml", manifest),
+                ("acme-tools/dist/plugin.wasm", "w"),
+                ("__MACOSX/acme-tools/._plugin.toml", "x"),
+            ],
+        );
+        let dest = tmp.path().join("b");
+        let got = unpack(&folder, &dest).unwrap();
+        assert_eq!(got.files, [PathBuf::from("dist/plugin.wasm")]);
+        assert!(dest.join(MANIFEST_FILE).is_file());
+        assert!(!dest.join("__MACOSX").exists() && !dest.join("acme-tools").exists());
+
+        // Two folders, a manifest one level too deep, or none (an IntelliJ plugin): not a package.
+        for (name, entries) in [
+            ("two.zip", &[("a/plugin.toml", manifest), ("b/x.txt", "x")][..]),
+            ("deep.zip", &[("a/b/plugin.toml", manifest)][..]),
+            ("intellij.zip", &[("my-plugin/lib/my-plugin.jar", "jar")][..]),
+        ] {
+            let path = tmp.path().join(name);
+            zip_of(&path, entries);
+            let err = unpack(&path, &tmp.path().join(name).with_extension("out")).unwrap_err();
+            assert!(err.contains("is not an OpenIDEA plugin"), "{name}: {err}");
+        }
+    }
+
+    #[test]
+    fn a_newer_index_still_revokes_and_moves() {
+        let newer = format!(
+            r#"{{"format": {}, "plugins": [{{"anything": "new"}}], "shape": "changed",
+                "publishers": [{{"id": "acme", "name": "ACME", "keys": [{{"key": "k1", "revoked": true}}]}}, {{"id": 5}}],
+                "revoked": [{{"id": "acme.bad", "reason": "malware"}}, {{"oops": 1}}],
+                "moved": "https://example.com/next.json"}}"#,
+            INDEX_FORMAT + 1
+        );
+        let index = Index::parse(&newer).unwrap();
+        assert!(index.is_newer());
+        assert!(index.plugins.is_empty() && index.offered().is_empty());
+        assert_eq!(index.revocation("acme.bad", "2.0.0").unwrap().reason, "malware");
+        assert!(index.key_revoked("k1"));
+        assert_eq!(index.moved.as_deref(), Some("https://example.com/next.json"));
+        // Fields this IDE doesn't know are ignored in its own format.
+        let current = format!(r#"{{"format": {INDEX_FORMAT}, "later": true, "plugins": []}}"#);
+        assert!(!Index::parse(&current).unwrap().is_newer());
+        assert!(Index::parse(r#"{"format": 0}"#).unwrap_err().contains("not supported"));
+        assert!(Index::parse(r#"{"plugins": []}"#).is_err());
+    }
+
+    fn keys<'a>(index: &'a mut Index, publisher: &str) -> &'a mut Vec<KeyEntry> {
+        &mut index.publishers.iter_mut().find(|p| p.id == publisher).unwrap().keys
+    }
+
+    #[test]
+    fn rotated_keys_continue_through_endorsements() {
+        let (k1, k2, k3) =
+            (PublisherKey::from_seed([1; 32]), PublisherKey::from_seed([2; 32]), PublisherKey::from_seed([3; 32]));
+        let mut index = index(&k1);
+        let endorsed = |by: &PublisherKey, key: &PublisherKey| KeyEntry {
+            endorsement: Some(by.endorse("acme", &key.public_base64())),
+            ..KeyEntry::new(key.public_base64())
+        };
+        keys(&mut index, "acme").push(endorsed(&k1, &k2));
+        keys(&mut index, "acme").push(endorsed(&k2, &k3));
+        let (p1, p2, p3) = (k1.public_base64(), k2.public_base64(), k3.public_base64());
+        assert!(index.succeeds("acme", &p1, &p1));
+        assert!(index.succeeds("acme", &p1, &p3), "through k2");
+        assert!(!index.succeeds("acme", &p3, &p1), "not backwards");
+        assert!(!index.succeeds("other", &p1, &p2));
+        // An endorsement for another publisher, or by a revoked key, doesn't count.
+        let mut foreign = index.clone();
+        keys(&mut foreign, "acme")[1].endorsement = Some(k1.endorse("evil", &p2));
+        assert!(!foreign.succeeds("acme", &p1, &p2));
+        let mut stolen = index.clone();
+        keys(&mut stolen, "acme")[0].revoked = true;
+        assert!(!stolen.succeeds("acme", &p1, &p2));
+
+        let sig = |key: &PublisherKey| key.sign("acme", "acme.tools", "1.0.0", "d");
+        assert!(signer_continues(Some(&index), Some(&sig(&k1)), Some(&sig(&k3))));
+        assert!(signer_continues(None, Some(&sig(&k1)), Some(&sig(&k1))));
+        assert!(!signer_continues(None, Some(&sig(&k1)), Some(&sig(&k2))), "no index to vouch");
+        let stranger = PublisherKey::from_seed([4; 32]);
+        assert!(!signer_continues(Some(&index), Some(&sig(&k1)), Some(&sig(&stranger))));
+        assert!(!signer_continues(Some(&index), Some(&sig(&k1)), None), "signed, then unsigned");
+        assert!(signer_continues(Some(&index), None, Some(&sig(&stranger))), "unsigned pins nothing");
+    }
+
+    #[test]
+    fn pinned_publishers_keep_their_built_in_keys() {
+        let (root, next, intruder) =
+            (PublisherKey::from_seed([1; 32]), PublisherKey::from_seed([2; 32]), PublisherKey::from_seed([5; 32]));
+        let mut index = index(&intruder);
+        index.publishers[0].id = "openidea".into();
+        keys(&mut index, "openidea").push(KeyEntry {
+            endorsement: Some(root.endorse("openidea", &next.public_base64())),
+            ..KeyEntry::new(next.public_base64())
+        });
+        let roots = [root.public_base64()];
+        let listed = |index: &Index| -> Vec<(String, bool)> {
+            let mut index = index.clone();
+            index.pin_publisher("openidea", "OpenIDEA", &roots);
+            keys(&mut index, "openidea").iter().map(|k| (k.key.clone(), k.revoked)).collect()
+        };
+        // The intruder's key goes, the successor the root endorsed stays, the root is added.
+        assert_eq!(listed(&index), [(next.public_base64(), false), (root.public_base64(), false)]);
+        let mut pinned = index.clone();
+        pinned.pin_publisher("openidea", "OpenIDEA", &roots);
+        let digest = "d";
+        let signed = |k: &PublisherKey| k.sign("openidea", "openidea.tools", "1.0.0", digest);
+        assert!(pinned.verify(&signed(&intruder), "openidea.tools", "1.0.0", digest).is_err());
+        assert!(pinned.verify(&signed(&next), "openidea.tools", "1.0.0", digest).is_ok());
+        // A revoked root stays revoked, and what it endorsed is no longer trusted.
+        keys(&mut index, "openidea").push(KeyEntry { revoked: true, ..KeyEntry::new(root.public_base64()) });
+        assert_eq!(listed(&index), [(root.public_base64(), true)]);
+
+        // A publisher missing from the index is added with its roots.
+        let mut empty = Index { format: INDEX_FORMAT, ..Index::default() };
+        empty.pin_publisher("openidea", "OpenIDEA", &[root.public_base64()]);
+        assert_eq!(empty.verify(&signed(&root), "openidea.tools", "1.0.0", digest).unwrap(), "openidea");
+        // No roots: the index decides.
+        let mut open = index.clone();
+        open.pin_publisher("openidea", "OpenIDEA", &[]);
+        assert_eq!(open, index);
+    }
+}
@@ -0,0 +1,175 @@
+//! The extension point contract (plan 4.1).
+
+use crate::capability::Capability;
+use crate::manifest::{Manifest, check_relative};
+use std::path::{Path, PathBuf};
+use std::sync::Arc;
+
+/// Where a contribution takes effect (plan 3, placement rules).
+#[derive(Clone, Copy, Debug, PartialEq, Eq, serde::Serialize, serde::Deserialize, specta::Type)]
+#[serde(rename_all = "camelCase")]
+pub enum Placement {
+    /// Projected to the client (menus, keybindings, themes, icons).
+    Ui,
+    /// Takes effect on the machine the project is on (languages, LSP, run configurations).
+    Workspace,
+}
+
+/// The package a declaration comes from, as extension points see it.
+#[derive(Clone, Debug)]
+pub struct Package {
+    pub manifest: Arc<Manifest>,
+    /// Package directory.
+    pub dir: PathBuf,
+    /// Hash of the package's files when they never change (an installed
+    /// copy): validated declarations are then reused from the
+    /// [`ContributionIndex`](crate::ContributionIndex).
+    pub digest: Option<Arc<str>>,
+}
+
+/// Largest single package file an extension point reads.
+pub const MAX_PACKAGE_FILE: u64 = 8 << 20;
+
+impl Package {
+    pub fn new(manifest: Manifest, dir: PathBuf) -> Self {
+        Self { manifest: Arc::new(manifest), dir, digest: None }
+    }
+
+    pub fn with_digest(mut self, digest: &str) -> Self {
+        self.digest = Some(digest.into());
+        self
+    }
+
+    pub fn id(&self) -> &str {
+        &self.manifest.id
+    }
+
+    /// Resolves a package-relative path, refusing anything that leaves the
+    /// package (`..`, absolute paths, symlinks pointing outside).
+    pub fn resolve(&self, rel: &Path) -> Result<PathBuf, String> {
+        check_relative(rel, "path")?;
+        let joined = self.dir.join(rel);
+        let real = joined.canonicalize().map_err(|_| format!("{}: no such file in the plugin", rel.display()))?;
+        let root = self.dir.canonicalize().map_err(|e| format!("plugin directory: {e}"))?;
+        if !real.starts_with(&root) {
+            return Err(format!("{}: points outside the plugin", rel.display()));
+        }
+        Ok(real)
+    }
+
+    pub fn read_bytes(&self, rel: &Path) -> Result<Vec<u8>, String> {
+        let real = self.resolve(rel)?;
+        let meta = std::fs::metadata(&real).map_err(|e| format!("{}: {e}", rel.display()))?;
+        if !meta.is_file() {
+            return Err(format!("{}: not a file", rel.display()));
+        }
+        if meta.len() > MAX_PACKAGE_FILE {
+            return Err(format!("{}: larger than {} MiB", rel.display(), MAX_PACKAGE_FILE >> 20));
+        }
+        std::fs::read(&real).map_err(|e| format!("{}: {e}", rel.display()))
+    }
+
+    pub fn read_text(&self, rel: &Path) -> Result<String, String> {
+        String::from_utf8(self.read_bytes(rel)?).map_err(|_| format!("{}: not UTF-8 text", rel.display()))
+    }
+}
+
+/// Undoes one committed contribution. Dropping without [`dispose`](Self::dispose) also disposes.
+#[must_use = "dropping a Disposable undoes the contribution"]
+pub struct Disposable(Option<Box<dyn FnOnce() + Send>>);
+
+impl Disposable {
+    pub fn new(f: impl FnOnce() + Send + 'static) -> Self {
+        Self(Some(Box::new(f)))
+    }
+
+    /// A contribution with nothing to undo.
+    pub fn noop() -> Self {
+        Self(None)
+    }
+
+    pub fn dispose(mut self) {
+        if let Some(f) = self.0.take() {
+            f();
+        }
+    }
+}
+
+impl Drop for Disposable {
+    fn drop(&mut self) {
+        if let Some(f) = self.0.take() {
+            f();
+        }
+    }
+}
+
+impl std::fmt::Debug for Disposable {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_str("Disposable")
+    }
+}
+
+pub type Commit = Box<dyn FnOnce() -> Result<Disposable, String> + Send>;
+
+/// A validated declaration, ready to take effect.
+pub struct Prepared {
+    /// Capabilities this declaration needs (a language with an LSP → `process:<binary>`).
+    pub capabilities: Vec<Capability>,
+    /// Package files the declaration references (copied on install).
+    pub files: Vec<PathBuf>,
+    /// Identity within the point: a later declaration with the same key replaces
+    /// the earlier one of the same plugin (re-registering a command).
+    pub key: Option<String>,
+    /// User-facing one-liner for the plugin details page ("Insert Date").
+    pub label: String,
+    /// Makes it take effect. Must not fail for reasons `prepare` could have checked.
+    pub commit: Commit,
+}
+
+impl Prepared {
+    pub fn new(label: impl Into<String>, commit: impl FnOnce() -> Result<Disposable, String> + Send + 'static) -> Self {
+        Self { capabilities: Vec::new(), files: Vec::new(), key: None, label: label.into(), commit: Box::new(commit) }
+    }
+
+    pub fn key(mut self, key: impl Into<String>) -> Self {
+        self.key = Some(key.into());
+        self
+    }
+
+    pub fn file(mut self, path: impl Into<PathBuf>) -> Self {
+        self.files.push(path.into());
+        self
+    }
+
+    pub fn capability(mut self, cap: Capability) -> Self {
+        if !self.capabilities.contains(&cap) {
+            self.capabilities.push(cap);
+        }
+        self
+    }
+}
+
+impl std::fmt::Debug for Prepared {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("Prepared").field("key", &self.key).field("label", &self.label).finish_non_exhaustive()
+    }
+}
+
+/// A kind of contribution (`contributes.<id>` in the manifest). Implemented by
+/// the crate that owns the feature; registered once in an [`crate::ExtensionRegistry`].
+pub trait ExtensionPoint: Send + Sync {
+    /// `"languages"`, `"iconThemes"`, …
+    fn id(&self) -> &'static str;
+
+    fn placement(&self) -> Placement;
+
+    /// Parses and validates one declaration without side effects, and works
+    /// out the capabilities it needs. `Ui` points validate completely here: the
+    /// client's projection is not allowed to fail.
+    fn prepare(&self, pkg: &Package, decl: toml::Value) -> Result<Prepared, String>;
+}
+
+/// Deserializes a declaration with serde, prefixing errors with the point id.
+pub fn decode<T: serde::de::DeserializeOwned>(point: &str, decl: toml::Value) -> Result<T, String> {
+    decl.try_into().map_err(|e: toml::de::Error| format!("contributes.{point}: {}", e.message()))
+}
@@ -0,0 +1,305 @@
+//! Extension points plus the contributions committed to them, accounted per plugin.
+
+use crate::capability::Capability;
+use crate::point::{Disposable, ExtensionPoint, Package, Placement, Prepared};
+use parking_lot::{Mutex, RwLock};
+use serde::{Deserialize, Serialize};
+use specta::Type;
+use std::collections::BTreeMap;
+use std::path::PathBuf;
+use std::sync::Arc;
+
+/// A contribution as the plugin details page lists it.
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize, Type)]
+#[serde(rename_all = "camelCase")]
+pub struct ContributionInfo {
+    pub point: String,
+    pub label: String,
+}
+
+struct Entry {
+    point: &'static str,
+    key: Option<String>,
+    label: String,
+    disposable: Disposable,
+}
+
+/// Every declaration of a package, validated; nothing has taken effect yet.
+pub struct PreparedSet {
+    pub plugin: String,
+    /// Union of what the declarations need (beyond the manifest's own list).
+    pub capabilities: Vec<Capability>,
+    /// Package files the declarations reference.
+    pub files: Vec<PathBuf>,
+    /// Declarations for extension points this host does not know (skipped).
+    pub warnings: Vec<String>,
+    items: Vec<(&'static str, Prepared)>,
+}
+
+impl PreparedSet {
+    pub fn is_empty(&self) -> bool {
+        self.items.is_empty()
+    }
+
+    pub fn len(&self) -> usize {
+        self.items.len()
+    }
+}
+
+impl std::fmt::Debug for PreparedSet {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("PreparedSet")
+            .field("plugin", &self.plugin)
+            .field("items", &self.items.len())
+            .field("warnings", &self.warnings)
+            .finish()
+    }
+}
+
+#[derive(Default)]
+pub struct ExtensionRegistry {
+    points: RwLock<BTreeMap<&'static str, Arc<dyn ExtensionPoint>>>,
+    /// plugin id → its contributions in commit order.
+    entries: Mutex<BTreeMap<String, Vec<Entry>>>,
+}
+
+impl ExtensionRegistry {
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// Adds an extension point. Ids are unique.
+    pub fn register(&self, point: Arc<dyn ExtensionPoint>) -> Result<(), String> {
+        let id = point.id();
+        crate::manifest::validate_point_id(id)?;
+        let mut points = self.points.write();
+        if points.contains_key(id) {
+            return Err(format!("extension point {id:?} is already registered"));
+        }
+        points.insert(id, point);
+        Ok(())
+    }
+
+    pub fn point_ids(&self) -> Vec<&'static str> {
+        self.points.read().keys().copied().collect()
+    }
+
+    pub fn placement(&self, point: &str) -> Option<Placement> {
+        self.points.read().get(point).map(|p| p.placement())
+    }
+
+    fn point(&self, id: &str) -> Option<Arc<dyn ExtensionPoint>> {
+        self.points.read().get(id).cloned()
+    }
+
+    /// Validates every `contributes.<point>` declaration of `pkg`. Fails as a
+    /// whole on the first invalid declaration; unknown points are skipped with
+    /// a warning (forward compatibility).
+    pub fn prepare(&self, pkg: &Package) -> Result<PreparedSet, String> {
+        let mut set = PreparedSet {
+            plugin: pkg.id().to_owned(),
+            capabilities: Vec::new(),
+            files: Vec::new(),
+            warnings: Vec::new(),
+            items: Vec::new(),
+        };
+        for point_id in pkg.manifest.contributes.keys() {
+            let Some(point) = self.point(point_id) else {
+                let msg = format!("contributes.{point_id}: not supported by this version of the IDE; skipped");
+                tracing::warn!(plugin = %pkg.id(), "{msg}");
+                set.warnings.push(msg);
+                continue;
+            };
+            for (i, decl) in pkg.manifest.declarations(point_id).into_iter().enumerate() {
+                let prepared = point
+                    .prepare(pkg, decl)
+                    .map_err(|e| format!("contributes.{point_id}[{i}]: {}", strip_prefix(&e, point_id)))?;
+                for cap in &prepared.capabilities {
+                    if !set.capabilities.contains(cap) {
+                        set.capabilities.push(cap.clone());
+                    }
+                }
+                for f in &prepared.files {
+                    if !set.files.contains(f) {
+                        set.files.push(f.clone());
+                    }
+                }
+                set.items.push((point.id(), prepared));
+            }
+        }
+        Ok(set)
+    }
+
+    /// Makes a prepared set take effect, all or nothing: if one commit fails,
+    /// the ones before it are disposed in reverse order.
+    pub fn commit(&self, set: PreparedSet) -> Result<(), String> {
+        let mut committed: Vec<Entry> = Vec::with_capacity(set.items.len());
+        for (point, prepared) in set.items {
+            let Prepared { key, label, commit, .. } = prepared;
+            match commit() {
+                Ok(disposable) => committed.push(Entry { point, key, label, disposable }),
+                Err(e) => {
+                    tracing::error!(plugin = %set.plugin, "contributes.{point}: commit failed: {e}");
+                    while let Some(entry) = committed.pop() {
+                        entry.disposable.dispose();
+                    }
+                    return Err(format!("contributes.{point}: {e}"));
+                }
+            }
+        }
+        let replaced = {
+            let mut entries = self.entries.lock();
+            let list = entries.entry(set.plugin).or_default();
+            let mut replaced = Vec::new();
+            for new in &committed {
+                if let Some(key) = &new.key
+                    && let Some(pos) = list.iter().position(|e| e.point == new.point && e.key.as_ref() == Some(key))
+                {
+                    replaced.push(list.remove(pos));
+                }
+            }
+            list.extend(committed);
+            replaced
+        };
+        for old in replaced.into_iter().rev() {
+            old.disposable.dispose();
+        }
+        Ok(())
+    }
+
+    /// Withdraws everything `plugin` contributed, newest first.
+    pub fn dispose_plugin(&self, plugin: &str) -> bool {
+        let list = self.entries.lock().remove(plugin).unwrap_or_default();
+        let any = !list.is_empty();
+        for entry in list.into_iter().rev() {
+            entry.disposable.dispose();
+        }
+        any
+    }
+
+    pub fn contributions(&self, plugin: &str) -> Vec<ContributionInfo> {
+        self.entries
+            .lock()
+            .get(plugin)
+            .map(|list| {
+                list.iter().map(|e| ContributionInfo { point: e.point.into(), label: e.label.clone() }).collect()
+            })
+            .unwrap_or_default()
+    }
+
+    /// How many contributions `plugin` has at `point`.
+    pub fn count(&self, plugin: &str, point: &str) -> usize {
+        self.entries.lock().get(plugin).map_or(0, |list| list.iter().filter(|e| e.point == point).count())
+    }
+
+    /// Plugins with at least one contribution.
+    pub fn plugins(&self) -> Vec<String> {
+        self.entries.lock().iter().filter(|(_, l)| !l.is_empty()).map(|(id, _)| id.clone()).collect()
+    }
+}
+
+fn strip_prefix<'a>(e: &'a str, point: &str) -> &'a str {
+    e.strip_prefix(&format!("contributes.{point}: ")).unwrap_or(e)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::manifest::Manifest;
+    use std::sync::atomic::{AtomicUsize, Ordering};
+
+    /// Records live items in a shared list; `fail = true` makes commit fail.
+    struct Recording {
+        id: &'static str,
+        live: Arc<Mutex<Vec<String>>>,
+        commits: Arc<AtomicUsize>,
+    }
+
+    impl ExtensionPoint for Recording {
+        fn id(&self) -> &'static str {
+            self.id
+        }
+        fn placement(&self) -> Placement {
+            Placement::Ui
+        }
+        fn prepare(&self, _pkg: &Package, decl: toml::Value) -> Result<Prepared, String> {
+            let name = decl.get("name").and_then(|v| v.as_str()).ok_or("missing name")?.to_owned();
+            let fail = decl.get("fail").and_then(|v| v.as_bool()).unwrap_or(false);
+            let (live, commits) = (self.live.clone(), self.commits.clone());
+            let label = name.clone();
+            let mut p = Prepared::new(label, move || {
+                commits.fetch_add(1, Ordering::SeqCst);
+                if fail {
+                    return Err("boom".into());
+                }
+                live.lock().push(name.clone());
+                Ok(Disposable::new(move || live.lock().retain(|n| *n != name)))
+            });
+            if let Some(f) = decl.get("file").and_then(|v| v.as_str()) {
+                p = p.file(f);
+            }
+            if decl.get("key").and_then(|v| v.as_bool()).unwrap_or(false) {
+                p = p.key("k");
+            }
+            Ok(p)
+        }
+    }
+
+    fn setup() -> (ExtensionRegistry, Arc<Mutex<Vec<String>>>) {
+        let reg = ExtensionRegistry::new();
+        let live = Arc::new(Mutex::new(Vec::new()));
+        let commits = Arc::new(AtomicUsize::new(0));
+        reg.register(Arc::new(Recording { id: "things", live: live.clone(), commits: commits.clone() })).unwrap();
+        reg.register(Arc::new(Recording { id: "others", live: live.clone(), commits })).unwrap();
+        (reg, live)
+    }
+
+    fn pkg(contributes: &str) -> Package {
+        let src = format!("id = \"p\"\nname = \"P\"\nversion = \"1.0.0\"\nengines.openidea = \"^1.0\"\n{contributes}");
+        Package::new(Manifest::parse(&src).unwrap(), PathBuf::from("/nonexistent"))
+    }
+
+    #[test]
+    fn commits_and_disposes_per_plugin() {
+        let (reg, live) = setup();
+        assert!(
+            reg.register(Arc::new(Recording { id: "things", live: live.clone(), commits: Default::default() }))
+                .is_err()
+        );
+        let p = pkg(
+            "[[contributes.things]]\nname = \"a\"\nfile = \"x.json\"\n[[contributes.things]]\nname = \"b\"\n[contributes.others]\nname = \"c\"",
+        );
+        let set = reg.prepare(&p).unwrap();
+        assert_eq!(set.len(), 3);
+        assert_eq!(set.files, [PathBuf::from("x.json")]);
+        assert!(live.lock().is_empty(), "prepare has no side effects");
+        reg.commit(set).unwrap();
+        assert_eq!(*live.lock(), ["c", "a", "b"]);
+        assert_eq!(reg.count("p", "things"), 2);
+        assert_eq!(reg.contributions("p").len(), 3);
+        assert!(reg.dispose_plugin("p"));
+        assert!(live.lock().is_empty());
+    }
+
+    #[test]
+    fn a_failed_commit_rolls_back() {
+        let (reg, live) = setup();
+        let p = pkg("[[contributes.things]]\nname = \"a\"\n[[contributes.things]]\nname = \"b\"\nfail = true");
+        let err = reg.commit(reg.prepare(&p).unwrap()).unwrap_err();
+        assert!(err.contains("boom"));
+        assert!(live.lock().is_empty(), "a was undone");
+        assert!(reg.contributions("p").is_empty());
+    }
+
+    #[test]
+    fn invalid_declarations_fail_prepare_and_unknown_points_warn() {
+        let (reg, _) = setup();
+        let err = reg.prepare(&pkg("[[contributes.things]]\nnope = 1")).unwrap_err();
+        assert_eq!(err, "contributes.things[0]: missing name");
+        let set =
+            reg.prepare(&pkg("[[contributes.futureThing]]\nx = 1\n[[contributes.things]]\nname = \"a\"")).unwrap();
+        assert_eq!(set.len(), 1);
+        assert_eq!(set.warnings.len(), 1);
+        assert!(set.warnings[0].contains("futureThing"));
+    }
+}
@@ -0,0 +1,247 @@
+//! UI contributions: validated declarations projected to the client.
+//!
+//! A `Ui` extension point validates a declaration completely in Rust and
+//! commits it as JSON into the [`UiStore`]; the client receives the store's
+//! snapshot and projects each item onto an existing `register*` function
+//! (`defineUiPoint` in `src/features/plugins/projection.ts`). Large payloads
+//! (icon SVGs) go into the store's assets and are fetched on demand.
+
+use crate::index::ContributionIndex;
+use crate::point::{Disposable, ExtensionPoint, Package, Placement, Prepared};
+use parking_lot::RwLock;
+use serde::{Deserialize, Serialize};
+use specta::Type;
+use std::collections::BTreeMap;
+use std::path::PathBuf;
+use std::sync::Arc;
+use std::sync::atomic::{AtomicU64, Ordering};
+
+/// One projected declaration.
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize, Type)]
+#[serde(rename_all = "camelCase")]
+pub struct UiContribution {
+    pub plugin_id: String,
+    /// Extension point id (`commands`, `iconThemes`, …).
+    pub point: String,
+    /// Stable within (plugin, point): the client keys its registrations on it.
+    pub key: String,
+    /// The validated declaration, shaped by the point.
+    #[specta(type = specta_typescript::Unknown)]
+    pub decl: serde_json::Value,
+}
+
+struct Item {
+    seq: u64,
+    contribution: UiContribution,
+}
+
+/// Committed UI contributions of all plugins.
+#[derive(Default)]
+pub struct UiStore {
+    items: RwLock<Vec<Item>>,
+    /// (plugin, asset id) → content.
+    assets: RwLock<BTreeMap<(String, String), Arc<str>>>,
+    seq: AtomicU64,
+    revision: AtomicU64,
+    index: RwLock<Option<Arc<ContributionIndex>>>,
+}
+
+impl UiStore {
+    pub fn new() -> Arc<Self> {
+        Arc::new(Self::default())
+    }
+
+    /// Adds an item; the returned disposable removes it.
+    pub fn insert(self: &Arc<Self>, contribution: UiContribution) -> Disposable {
+        let seq = self.seq.fetch_add(1, Ordering::Relaxed);
+        self.items.write().push(Item { seq, contribution });
+        self.revision.fetch_add(1, Ordering::Release);
+        let store = Arc::downgrade(self);
+        Disposable::new(move || {
+            if let Some(store) = store.upgrade() {
+                store.items.write().retain(|i| i.seq != seq);
+                store.revision.fetch_add(1, Ordering::Release);
+            }
+        })
+    }
+
+    /// Stores assets of a plugin (ids are unique per plugin; later ones replace).
+    pub fn insert_assets(self: &Arc<Self>, plugin: &str, assets: Vec<(String, String)>) -> Disposable {
+        let keys: Vec<(String, String)> = assets.iter().map(|(id, _)| (plugin.to_owned(), id.clone())).collect();
+        {
+            let mut map = self.assets.write();
+            for (id, content) in assets {
+                map.insert((plugin.to_owned(), id), Arc::from(content));
+            }
+        }
+        let store = Arc::downgrade(self);
+        Disposable::new(move || {
+            if let Some(store) = store.upgrade() {
+                let mut map = store.assets.write();
+                for k in keys {
+                    map.remove(&k);
+                }
+            }
+        })
+    }
+
+    pub fn asset(&self, plugin: &str, id: &str) -> Option<Arc<str>> {
+        self.assets.read().get(&(plugin.to_owned(), id.to_owned())).cloned()
+    }
+
+    /// Assets of `plugin` whose id starts with `prefix`.
+    pub fn assets_with_prefix(&self, plugin: &str, prefix: &str) -> Vec<(String, Arc<str>)> {
+        self.assets
+            .read()
+            .range((plugin.to_owned(), prefix.to_owned())..)
+            .take_while(|((p, id), _)| p == plugin && id.starts_with(prefix))
+            .map(|((_, id), v)| (id.clone(), v.clone()))
+            .collect()
+    }
+
+    /// Where [`UiPoint`]s keep validated declarations of installed packages.
+    pub fn set_index(&self, index: Option<Arc<ContributionIndex>>) {
+        *self.index.write() = index;
+    }
+
+    /// Bumped on every change: clients compare it to skip re-projection.
+    pub fn revision(&self) -> u64 {
+        self.revision.load(Ordering::Acquire)
+    }
+
+    pub fn snapshot(&self) -> Vec<UiContribution> {
+        self.items.read().iter().map(|i| i.contribution.clone()).collect()
+    }
+
+    /// Items of one point, optionally of one plugin.
+    pub fn items(&self, point: &str, plugin: Option<&str>) -> Vec<UiContribution> {
+        self.items
+            .read()
+            .iter()
+            .filter(|i| i.contribution.point == point && plugin.is_none_or(|p| i.contribution.plugin_id == p))
+            .map(|i| i.contribution.clone())
+            .collect()
+    }
+}
+
+/// What a [`UiPoint`]'s validator produces for one declaration.
+#[derive(Debug, Serialize, Deserialize)]
+pub struct UiDecl {
+    pub key: String,
+    pub label: String,
+    pub json: serde_json::Value,
+    /// Package files referenced (copied on install).
+    pub files: Vec<PathBuf>,
+    /// Large validated payloads fetched separately by the client.
+    pub assets: Vec<(String, String)>,
+}
+
+impl UiDecl {
+    pub fn new(key: impl Into<String>, label: impl Into<String>, json: serde_json::Value) -> Self {
+        Self { key: key.into(), label: label.into(), json, files: Vec::new(), assets: Vec::new() }
+    }
+}
+
+type Validate = dyn Fn(&Package, toml::Value) -> Result<UiDecl, String> + Send + Sync;
+
+/// A `Ui` extension point defined by a validator: committing stores the
+/// validated JSON (and assets) in the [`UiStore`]. Most UI contribution types
+/// (menus, keybindings, status bar items, icon themes) are one of these.
+pub struct UiPoint {
+    id: &'static str,
+    store: Arc<UiStore>,
+    validate: Box<Validate>,
+}
+
+impl UiPoint {
+    pub fn new(
+        id: &'static str,
+        store: Arc<UiStore>,
+        validate: impl Fn(&Package, toml::Value) -> Result<UiDecl, String> + Send + Sync + 'static,
+    ) -> Self {
+        Self { id, store, validate: Box::new(validate) }
+    }
+}
+
+impl ExtensionPoint for UiPoint {
+    fn id(&self) -> &'static str {
+        self.id
+    }
+
+    fn placement(&self) -> Placement {
+        Placement::Ui
+    }
+
+    fn prepare(&self, pkg: &Package, decl: toml::Value) -> Result<Prepared, String> {
+        let index = pkg.digest.as_ref().and_then(|_| self.store.index.read().clone());
+        let ui = match index.as_ref().and_then(|i| i.get(pkg, self.id, &decl)) {
+            Some(ui) => ui,
+            None => match &index {
+                Some(i) => {
+                    let ui = (self.validate)(pkg, decl.clone())?;
+                    i.put(pkg, self.id, &decl, &ui);
+                    ui
+                }
+                None => (self.validate)(pkg, decl)?,
+            },
+        };
+        let UiDecl { key, label, json, files, assets } = ui;
+        let store = self.store.clone();
+        let contribution =
+            UiContribution { plugin_id: pkg.id().to_owned(), point: self.id.to_owned(), key: key.clone(), decl: json };
+        let plugin = pkg.id().to_owned();
+        let mut prepared = Prepared::new(label, move || {
+            let item = store.insert(contribution);
+            if assets.is_empty() {
+                return Ok(item);
+            }
+            let assets = store.insert_assets(&plugin, assets);
+            Ok(Disposable::new(move || {
+                item.dispose();
+                assets.dispose();
+            }))
+        })
+        .key(key);
+        prepared.files = files;
+        Ok(prepared)
+    }
+}
+
+/// TOML declaration → JSON for the client.
+pub fn to_json(v: &toml::Value) -> serde_json::Value {
+    serde_json::to_value(v).unwrap_or(serde_json::Value::Null)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::manifest::Manifest;
+    use crate::registry::ExtensionRegistry;
+
+    #[test]
+    fn ui_point_projects_into_the_store() {
+        let store = UiStore::new();
+        let reg = ExtensionRegistry::new();
+        reg.register(Arc::new(UiPoint::new("badges", store.clone(), |_pkg, decl| {
+            let text = decl.get("text").and_then(|v| v.as_str()).ok_or("missing text")?.to_owned();
+            let mut d = UiDecl::new(text.clone(), text.clone(), serde_json::json!({ "text": text }));
+            d.assets.push((format!("badge/{text}"), "<svg/>".into()));
+            Ok(d)
+        })))
+        .unwrap();
+        let src = "id = \"p\"\nname = \"P\"\nversion = \"1.0.0\"\nengines.openidea = \"^1.0\"\n\
+                   [[contributes.badges]]\ntext = \"hi\"";
+        let pkg = Package::new(Manifest::parse(src).unwrap(), PathBuf::from("/x"));
+        let rev = store.revision();
+        reg.commit(reg.prepare(&pkg).unwrap()).unwrap();
+        assert!(store.revision() > rev);
+        let items = store.items("badges", Some("p"));
+        assert_eq!(items.len(), 1);
+        assert_eq!(items[0].decl["text"], "hi");
+        assert_eq!(store.asset("p", "badge/hi").as_deref(), Some("<svg/>"));
+        assert_eq!(store.assets_with_prefix("p", "badge/").len(), 1);
+        reg.dispose_plugin("p");
+        assert!(store.snapshot().is_empty());
+        assert!(store.asset("p", "badge/hi").is_none());
+    }
+}
@@ -0,0 +1,136 @@
+//! Syntax check for `when` clauses in UI declarations. The client evaluates
+//! them (`src/platform/context.ts`); validating here keeps the client's
+//! projection from failing. Grammar (same as the client):
+//!
+//! ```text
+//! expr := or ; or := and ("||" and)* ; and := unary ("&&" unary)*
+//! unary := "!" unary | "(" expr ")" | cmp ; cmp := key (("==" | "!=") value)?
+//! ```
+
+const MAX_LEN: usize = 512;
+
+#[derive(Debug, PartialEq)]
+enum Tok<'a> {
+    Id(&'a str),
+    Str,
+    Op(&'a str),
+}
+
+fn tokenize(src: &str) -> Result<Vec<Tok<'_>>, String> {
+    let mut out = Vec::new();
+    let b = src.as_bytes();
+    let mut i = 0;
+    while i < b.len() {
+        let c = b[i] as char;
+        if c.is_whitespace() {
+            i += 1;
+        } else if ["&&", "||", "==", "!="].iter().any(|op| src[i..].starts_with(op)) {
+            out.push(Tok::Op(&src[i..i + 2]));
+            i += 2;
+        } else if matches!(c, '!' | '(' | ')') {
+            out.push(Tok::Op(&src[i..i + 1]));
+            i += 1;
+        } else if c == '\'' || c == '"' {
+            let end = src[i + 1..].find(c).ok_or_else(|| format!("unterminated string in when clause: {src}"))?;
+            out.push(Tok::Str);
+            i += end + 2;
+        } else {
+            let len = src[i..]
+                .find(|ch: char| !(ch.is_alphanumeric() || matches!(ch, '_' | '.' | '-' | ':' | '/')))
+                .unwrap_or(src.len() - i);
+            if len == 0 {
+                return Err(format!("unexpected '{c}' in when clause: {src}"));
+            }
+            out.push(Tok::Id(&src[i..i + len]));
+            i += len;
+        }
+    }
+    Ok(out)
+}
+
+/// Checks a `when` clause; empty means "always".
+pub fn validate_when(src: &str) -> Result<(), String> {
+    if src.len() > MAX_LEN {
+        return Err(format!("when clause longer than {MAX_LEN} bytes"));
+    }
+    if src.trim().is_empty() {
+        return Ok(());
+    }
+    let toks = tokenize(src)?;
+    let mut p = 0;
+    parse_or(&toks, &mut p, src)?;
+    if p != toks.len() {
+        return Err(format!("unexpected token in when clause: {src}"));
+    }
+    Ok(())
+}
+
+fn parse_or(t: &[Tok], p: &mut usize, src: &str) -> Result<(), String> {
+    parse_and(t, p, src)?;
+    while t.get(*p) == Some(&Tok::Op("||")) {
+        *p += 1;
+        parse_and(t, p, src)?;
+    }
+    Ok(())
+}
+
+fn parse_and(t: &[Tok], p: &mut usize, src: &str) -> Result<(), String> {
+    parse_unary(t, p, src)?;
+    while t.get(*p) == Some(&Tok::Op("&&")) {
+        *p += 1;
+        parse_unary(t, p, src)?;
+    }
+    Ok(())
+}
+
+fn parse_unary(t: &[Tok], p: &mut usize, src: &str) -> Result<(), String> {
+    match t.get(*p) {
+        Some(Tok::Op("!")) => {
+            *p += 1;
+            parse_unary(t, p, src)
+        }
+        Some(Tok::Op("(")) => {
+            *p += 1;
+            parse_or(t, p, src)?;
+            if t.get(*p) != Some(&Tok::Op(")")) {
+                return Err(format!("missing ')' in when clause: {src}"));
+            }
+            *p += 1;
+            Ok(())
+        }
+        Some(Tok::Id(_)) => {
+            *p += 1;
+            if matches!(t.get(*p), Some(Tok::Op("==" | "!="))) {
+                *p += 1;
+                match t.get(*p) {
+                    Some(Tok::Id(_) | Tok::Str) => *p += 1,
+                    _ => return Err(format!("missing value after comparison in when clause: {src}")),
+                }
+            }
+            Ok(())
+        }
+        _ => Err(format!("expected a context key in when clause: {src}")),
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::validate_when;
+
+    #[test]
+    fn accepts_the_client_grammar() {
+        for ok in [
+            "",
+            "editorFocus",
+            "editorLang == rust",
+            "editorLang != 'rust' && !readOnly",
+            "(a || b) && toolWindow.project.active",
+            "resourceScheme == file:/x",
+        ] {
+            assert!(validate_when(ok).is_ok(), "{ok}");
+        }
+        for bad in ["a &&", "(a", "a == ", "== a", "a b", "a $ b", "'x", "!()"] {
+            assert!(validate_when(bad).is_err(), "{bad}");
+        }
+    }
+}