docs(contributing): add contribution volume and batching guidance

Documents expectations for keeping contribution flow sustainable during the
stabilization phase: one issue per bug (no bundled multi-finding audits), keep
only a few items open at a time, and hold AI-assisted contributions to the same
per-item verification bar. Complements the existing issue-approved gate, which
already covers PR-to-issue linkage and scope; the gap was submission volume.

.github/ISSUE_TEMPLATE/config.yml

@@ -1,5 +1,11 @@
 blank_issues_enabled: false
 contact_links:
+  - name: Questions and setup help
+    url: https://github.com/Gitlawb/zero/discussions/categories/q-a
+    about: Ask in Discussions Q&A. Include zero --version, your OS, provider/model, and zero doctor output for setup problems.
+  - name: Feature ideas
+    url: https://github.com/Gitlawb/zero/discussions/categories/ideas
+    about: Propose and discuss ideas in Discussions before opening a PR (Zero is in controlled development, see CONTRIBUTING.md).
   - name: Security vulnerability
     url: https://github.com/Gitlawb/zero/security/advisories/new
     about: Report security issues privately via GitHub Security Advisories (see SECURITY.md). Do not file a public issue.

.github/ISSUE_TEMPLATE/feature_request.yml

@@ -1,12 +1,22 @@
-name: Feature request
-description: Propose a new capability or change
+name: Feature request (previously discussed)
+description: File only after your idea gained traction in Discussions Ideas or a maintainer asked for a tracking issue
 labels: ["enhancement"]
 body:
   - type: markdown
     attributes:
       value: |
-        Please do not begin implementation until the issue has been reviewed and marked with the
+        New feature ideas start in [Discussions Ideas](https://github.com/Gitlawb/zero/discussions/categories/ideas),
+        not here. This form is for the step after that: an idea that gained traction in Discussions,
+        or one a maintainer asked to have tracked as an issue. Please link the discussion below.
+        Do not begin implementation until the issue has been reviewed and marked with the
         `issue-approved` label (see CONTRIBUTING.md).
+  - type: input
+    id: discussion
+    attributes:
+      label: Ideas discussion
+      description: Link to the Discussions Ideas thread (or note which maintainer asked for this issue).
+    validations:
+      required: true
   - type: textarea
     id: problem
     attributes:

.gitignore

@@ -55,3 +55,6 @@ docs/superpowers/
 zero-termux-arm64
 zero-linux-sandbox
 zero-seccomp
+
+# Generated benchmark reports are evidence for one configuration, never tree state
+internal/perfbench/reports/*.json

.release-please-manifest.json

@@ -1 +1 @@
-{".":"0.3.0"}
+{".":"0.4.0"}

AGENTS.md

@@ -1,27 +1,71 @@
----
-description: Project guidelines for the open-source CLI coding agent (zero) repository.
-globs: "*.go, *.js, *.md, *.json, *.toml, *.yaml, *.yml"
-alwaysApply: false
----
+# Repository Guidelines for Zero
 
-# Repository Conventions for Zero
+These instructions apply to all work in this repository. For the user-facing
+guide to extending Zero with specialists, hooks, plugins, MCP, and skills, see
+[docs/EXTENDING.md](docs/EXTENDING.md).
 
-This file outlines the project conventions and repository guidelines for coding agents when working on the `zero` repository. For the general guide on how to extend Zero (write specialist sub-agents, hooks, plugins, MCP, skills), see [docs/EXTENDING.md](docs/EXTENDING.md).
+## 1. Contribution and Pull Request Rules
 
-## 1. Project Conventions
+- Before opening any pull request, **all contributors**—including maintainers,
+  community contributors, and coding agents—must read and follow
+  [CONTRIBUTING.md](CONTRIBUTING.md).
+- Community pull requests require an existing parent issue with the
+  `issue-approved` label. Team members may open pull requests through the
+  internal development process described in `CONTRIBUTING.md`.
+- Keep each change focused on the approved or assigned scope. Do not include
+  unrelated fixes, refactors, formatting churn, generated output, or existing
+  local changes in the same commit or pull request.
+- Discuss new implementation languages, runtimes, major dependency changes,
+  and broad architectural rewrites with maintainers before implementation.
+- Pull request descriptions must explain what changed and why, link the parent
+  issue when required, and list the tests or verification performed. Include
+  screenshots or a short recording for user-visible UI changes when practical.
 
-- Build with `make`, not `go build` directly.
-- Tests live next to the source file (`foo_test.go` next to `foo.go`).
-- Run `make lint` before opening a PR.
-- Never edit files under `third_party/` — those are vendored.
-- Unify functions/methods where possible to prevent codebase inflation. Prefer a single cross-platform function with conditional checks over duplicating helpers per platform.
+## 2. Repository and Implementation Conventions
 
-## 2. Guidelines for Coding Agents
+- Use the Go version declared in `go.mod`. Do not hardcode a different local
+  toolchain version in scripts or documentation.
+- Use the repository build and release commands (`make` and
+  `go run ./cmd/zero-release ...`) instead of inventing parallel build flows.
+- Keep tests beside their source files (`foo_test.go` next to `foo.go`). Add a
+  regression test for behavior changes and run affected concurrent code under
+  the race detector.
+- Never edit files under `third_party/`; they are vendored.
+- Prefer one cross-platform function with small conditional checks over
+  duplicated platform-specific helpers when the behavior can remain unified.
+- Do not commit generated benchmark reports from
+  `internal/perfbench/reports/*.json`; reports are configuration-specific
+  evidence, not repository state.
+- Preserve the user's working tree. Do not overwrite, delete, stage, or commit
+  unrelated tracked or untracked files.
 
-If you are an AI coding agent executing tasks in this repository, you **MUST** run all Go code quality and security checks before committing code or completing your task:
+## 3. Required Validation
 
-1. **Format & Vet**: Run `go fmt ./...` and `go vet ./...`.
-2. **Lint**: Run `go run github.com/golangci/golangci-lint/v2/cmd/[email protected] run --enable-only unused,ineffassign,staticcheck ./...`.
-3. **Security**: Run `go run golang.org/x/vuln/cmd/[email protected] ./...`.
+Run validation from the repository root before committing, opening a pull
+request, or completing an implementation task:
 
-If any check fails or cannot be run, do not ignore it. Prompt the user for instructions or setup assistance before proceeding.
+1. **Formatting check**: `make fmt-check`. If it fails, format with
+   `go fmt ./...` (or `make fmt`) and run the check again.
+2. **Vet**: `go vet ./...` (or `make vet`).
+3. **Tests**: `go test ./...`. Use `make test` for the full race-enabled suite,
+   or run focused tests with `-race`, when concurrency is affected.
+4. **Build**: `go run ./cmd/zero-release build`.
+5. **Smoke test**: `go run ./cmd/zero-release smoke`.
+6. **Advisory lint**:
+   `go run github.com/golangci/golangci-lint/v2/cmd/[email protected] run --enable-only unused,ineffassign,staticcheck ./...`.
+7. **Security**:
+   `go run golang.org/x/vuln/cmd/[email protected] ./...`.
+8. **Diff hygiene**: `git diff HEAD --check` (covers staged and unstaged
+   tracked changes).
+
+`make lint` currently runs the formatting check and `go vet`; it does **not**
+run golangci-lint. The pinned golangci-lint job is advisory in CI while the
+existing repository-wide backlog is cleaned up. Fix findings introduced by or
+related to the current change. Unrelated pre-existing advisory findings do not
+justify expanding a focused pull request; report them separately.
+
+Formatting, vet, tests, build, smoke, diff hygiene, and govulncheck are hard
+requirements. If a related check fails, fix it. If a required check cannot run
+because of the environment or fails for an unrelated external reason, report
+the exact failure and obtain maintainer direction rather than silently ignoring
+it.

CHANGELOG.md

@@ -6,6 +6,60 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 aims to follow [Semantic Versioning](https://semver.org/spec/v2.0.0.html) once the first release is
 tagged. Until then, source builds report the version `dev`.
 
+## [0.4.0](https://github.com/Gitlawb/zero/compare/v0.3.0...v0.4.0) (2026-07-17)
+
+
+### Features
+
+* **aimlapi:** AI/ML API provider with guided onboarding (top-up + key issuance) ([#655](https://github.com/Gitlawb/zero/issues/655)) ([6b9c2f0](https://github.com/Gitlawb/zero/commit/6b9c2f0c083e02bcd3aad68fb7af0501a9e7cd61))
+* **cli:** show ZERO wordmark on --version ([#673](https://github.com/Gitlawb/zero/issues/673)) ([9acb411](https://github.com/Gitlawb/zero/commit/9acb4113cc3337b3f361a16278e9cf11ca105e34))
+* **cli:** wire MCP serve WorkspaceRoot and --add-dir scope ([#694](https://github.com/Gitlawb/zero/issues/694)) ([75a78e7](https://github.com/Gitlawb/zero/commit/75a78e715bf23154f69c8c79cb58eb4b535b2a2a))
+* **npm:** ship the native binary as platform optionalDependencies ([#626](https://github.com/Gitlawb/zero/issues/626)) ([5e1405d](https://github.com/Gitlawb/zero/commit/5e1405d0b7abff5b3ccb3cfdb66d64d6d3322922))
+* **perf:** emit prompt-prefix hash fingerprint per turn ([#704](https://github.com/Gitlawb/zero/issues/704)) ([1c5c6e7](https://github.com/Gitlawb/zero/commit/1c5c6e78a8a0e228bdf53d7be90934fbce9d98c3))
+* **providers:** add AI/ML API preset (rebased onto main) ([#621](https://github.com/Gitlawb/zero/issues/621)) ([d66a9dd](https://github.com/Gitlawb/zero/commit/d66a9dda69c32aa59f4bea903cfefe00d4b7adef))
+* **providers:** refresh MiniMax model coverage ([#665](https://github.com/Gitlawb/zero/issues/665)) ([fa3052a](https://github.com/Gitlawb/zero/commit/fa3052a1422a4ad30a3a6295829564f42dee31a8))
+* **skills:** discover shared ~/.agents/skills with multi-root skill loading ([#696](https://github.com/Gitlawb/zero/issues/696)) ([7d57999](https://github.com/Gitlawb/zero/commit/7d579996b43741a2e57e3e38fcdd8484fcfc34e9))
+* **tui:** Ctrl+X leader chords and emacs menu navigation ([#699](https://github.com/Gitlawb/zero/issues/699)) ([7f669f4](https://github.com/Gitlawb/zero/commit/7f669f455021be51319ee3b8298cd48a17f745c7))
+* **tui:** press up to edit queued messages ([#656](https://github.com/Gitlawb/zero/issues/656)) ([4c986d3](https://github.com/Gitlawb/zero/commit/4c986d327b5ed26338d295c23bea5839681db8d0))
+
+
+### Bug Fixes
+
+* **acp:** make truncateHint rune-safe ([#614](https://github.com/Gitlawb/zero/issues/614)) ([ddc4927](https://github.com/Gitlawb/zero/commit/ddc4927aac5544bf4dd2c46615aeda5a81c96576))
+* **agent,tui:** resolve git branch detection when starting Zero in subdirectories ([#613](https://github.com/Gitlawb/zero/issues/613)) ([0184581](https://github.com/Gitlawb/zero/commit/0184581ec234ea414e0a47bc33e8b0f4ddfb497b))
+* **agent:** raise default and deep-mode turn budgets ([#650](https://github.com/Gitlawb/zero/issues/650)) ([635c93a](https://github.com/Gitlawb/zero/commit/635c93af51ebc20f3e0917917e55a79edfe27c35))
+* **cli:** prevent consuming positional arguments as flag values ([#619](https://github.com/Gitlawb/zero/issues/619)) ([5b4f48d](https://github.com/Gitlawb/zero/commit/5b4f48d2dcb66402c13bde0c3cfe9c9371da19fb))
+* **config:** enforce MCP trust boundary so project config cannot override user disable ([#609](https://github.com/Gitlawb/zero/issues/609)) ([4d8c31c](https://github.com/Gitlawb/zero/commit/4d8c31cf16a3080344e3be7039408fcae71c075d)), closes [#512](https://github.com/Gitlawb/zero/issues/512)
+* **config:** surface unknown/typo'd config fields instead of silently dropping them ([#645](https://github.com/Gitlawb/zero/issues/645)) ([893b7b4](https://github.com/Gitlawb/zero/commit/893b7b424cc203a2fcf92327a4e25c84286a90e0))
+* **cron:** prevent cron job Mutate from clobbering concurrent updates ([#630](https://github.com/Gitlawb/zero/issues/630)) ([e4bd703](https://github.com/Gitlawb/zero/commit/e4bd703cfb28dab2dfa3c2ddba46237e1bb2e164))
+* **daemon:** handle os.ErrPermission as collision during O_EXCL lock creation ([#616](https://github.com/Gitlawb/zero/issues/616)) ([8ea5384](https://github.com/Gitlawb/zero/commit/8ea53841a5d54c37a153779ae86bea010659433c))
+* **exec:** stop false INCOMPLETE downgrades on conversational final messages ([#608](https://github.com/Gitlawb/zero/issues/608)) ([b6117af](https://github.com/Gitlawb/zero/commit/b6117af86d6bc87a4ee66910e99d76cb16b03fed))
+* harden MCP credential boundaries ([#597](https://github.com/Gitlawb/zero/issues/597)) ([fdddb05](https://github.com/Gitlawb/zero/commit/fdddb05ba84b1600ae6c3a20028bf83afe474c44))
+* **hooks:** fail closed on launch failures for beforeTool hooks ([#629](https://github.com/Gitlawb/zero/issues/629)) ([dc06fe7](https://github.com/Gitlawb/zero/commit/dc06fe72caf45f72d2cba1e8a835c0f5b405c1e8))
+* **hooks:** run sessionEnd hooks after Esc/Ctrl+C interrupts ([#606](https://github.com/Gitlawb/zero/issues/606)) ([824ecdb](https://github.com/Gitlawb/zero/commit/824ecdbcf9c467c35ef4e2666770fdadcb5bf402))
+* **keyring:** pass generic password via stdin on macOS ([#574](https://github.com/Gitlawb/zero/issues/574)) ([91ea6de](https://github.com/Gitlawb/zero/commit/91ea6ded7503538834a84d090f78670a363c62d3))
+* **lock:** prevent POSIX lock file overwrite and leak on Windows/Unix ([#628](https://github.com/Gitlawb/zero/issues/628)) ([da41c3a](https://github.com/Gitlawb/zero/commit/da41c3a75b782d6e0836fe13346321e40a90fbb4))
+* **openai:** omit prompt_cache_key for openai-compatible providers ([#636](https://github.com/Gitlawb/zero/issues/636)) ([1af5882](https://github.com/Gitlawb/zero/commit/1af58828eb3c22567599c000736c913a290959d2)), closes [#624](https://github.com/Gitlawb/zero/issues/624)
+* **plugins:** resolve relative executable paths against plugin root ([#627](https://github.com/Gitlawb/zero/issues/627)) ([2efe6d5](https://github.com/Gitlawb/zero/commit/2efe6d539e29374b3ef39c2290bdea81f33a228b))
+* **sandbox:** remove windowsWriteRestricted flag to fix DenyRead bypass ([#612](https://github.com/Gitlawb/zero/issues/612)) ([3d96ac7](https://github.com/Gitlawb/zero/commit/3d96ac7e55c760a97f28c0e6ceaf1ec3b4ab717a))
+* **sandbox:** scrub dynamic credential env vars ([#682](https://github.com/Gitlawb/zero/issues/682)) ([9043bae](https://github.com/Gitlawb/zero/commit/9043baedcff7776c7373645b57563cac06b31847))
+* **sandbox:** scrub sensitive credentials from sandbox environment ([#660](https://github.com/Gitlawb/zero/issues/660)) ([6fc1220](https://github.com/Gitlawb/zero/commit/6fc1220f6ac66fb3ae67b637cbbed7068d2213c0))
+* **sandbox:** unblock git fetch/commit/add under the write-restricted sandbox ([#654](https://github.com/Gitlawb/zero/issues/654)) ([5c4815a](https://github.com/Gitlawb/zero/commit/5c4815a66ed07d9cf90b825adfd936d3ac07639d))
+* **sandbox:** use WRITE_RESTRICTED token when no DenyRead paths are configured ([#658](https://github.com/Gitlawb/zero/issues/658)) ([a5d2e32](https://github.com/Gitlawb/zero/commit/a5d2e327c8681671aa8a9e5378801215b747edcf))
+* **securefile,credstore:** call Sync on temp file before close and rename ([#631](https://github.com/Gitlawb/zero/issues/631)) ([212734a](https://github.com/Gitlawb/zero/commit/212734adf3b5f982e22385161205aa1afe4634fe))
+* **securefile:** reclaim stale lock files to prevent permanent DOS ([#615](https://github.com/Gitlawb/zero/issues/615)) ([8536cc8](https://github.com/Gitlawb/zero/commit/8536cc87f7a885f9e436d6ef28f5f325201623dc))
+* **swarm:** wait for job.Runs directly in scheduler skip test ([#667](https://github.com/Gitlawb/zero/issues/667)) ([1bb6b57](https://github.com/Gitlawb/zero/commit/1bb6b5745af90321d1e657a12a1976cded5dd1bd))
+* **tools:** classify silent wrapped Windows command failures as sandbox denials ([#659](https://github.com/Gitlawb/zero/issues/659)) ([8bd9742](https://github.com/Gitlawb/zero/commit/8bd9742fa95c41b93ea4e718628aed0ff3ae9dd0))
+* **tools:** preserve SysProcAttr during PTY fallback ([#618](https://github.com/Gitlawb/zero/issues/618)) ([f78b36c](https://github.com/Gitlawb/zero/commit/f78b36c770daa4577a9f99265b18a354454e36eb))
+* **tui:** resolve pending askUser callbacks to prevent runner hangs ([#620](https://github.com/Gitlawb/zero/issues/620)) ([aa73a76](https://github.com/Gitlawb/zero/commit/aa73a76f1bd1b6fe97bac2fbff2d61b7474139f2))
+* **tui:** stop the composer cursor blinking while typing or unfocused ([#672](https://github.com/Gitlawb/zero/issues/672)) ([2b42cd5](https://github.com/Gitlawb/zero/commit/2b42cd567b96d6f7e0818594e53ff31cce1e42e9))
+* **windows:** resolve absolute path for taskkill to prevent hijacking ([#617](https://github.com/Gitlawb/zero/issues/617)) ([2db00ee](https://github.com/Gitlawb/zero/commit/2db00ee3d57db97e0fbe23cb8628e8bcb47f6f09))
+
+
+### Performance Improvements
+
+* **tools:** add explicit effect metadata for safe concurrency ([#705](https://github.com/Gitlawb/zero/issues/705)) ([8ef8576](https://github.com/Gitlawb/zero/commit/8ef8576df7d0775a5b815bc0776a794cadb75c34))
+
 ## [0.3.0](https://github.com/Gitlawb/zero/compare/v0.2.0...v0.3.0) (2026-07-09)
 
 
@@ -127,14 +181,19 @@ tagged. Until then, source builds report the version `dev`.
 ## [Unreleased]
 
 ### Added
+- Shared multi-agent skills discovery: when present, `~/.agents/skills` is searched after the primary
+  Zero skills dir (and before plugin skill roots). `zero skills list` / `info` and the runtime `skill`
+  tool share one multi-root discovery path; install/remove/lock still target only the Zero skills directory.
 - `SECURITY.md` with a private vulnerability-reporting path, `CODE_OF_CONDUCT.md`, this changelog, and
   GitHub issue/PR templates.
 - Interactive `/theme` picker: bare `/theme` opens a popup that live-previews each palette as you move
   and applies on select (Esc reverts).
-- Ten built-in color themes alongside the `dark`/`light` built-ins — `dracula`, `nord`, `gruvbox`,
-  `tokyo-night`, `catppuccin`, `one-dark`, `solarized-dark`, `rose-pine`, `everforest`, and
-  `solarized-light` — selectable via `/theme <name>`, `--theme <name>`, or `ZERO_THEME`. Every palette
-  is contrast-audited to WCAG AA. The built-in light theme was reworked for legibility.
+- Twelve built-in color themes alongside the `dark`/`light` built-ins — `dracula`, `nord`, `gruvbox`,
+  `tokyo-night`, `catppuccin`, `one-dark`, `solarized-dark`, `rose-pine`, `everforest`,
+  `solarized-light`, `dune`, and `neon` — selectable via `/theme <name>`, `--theme <name>`, or
+  `ZERO_THEME`. Every palette is contrast-audited to WCAG AA, and the new presets are additionally
+  audited after xterm-256 downsampling; see [docs/THEMES.md](docs/THEMES.md). The built-in light
+  theme was reworked for legibility.
 - `--theme <name>` flag for the TUI, accepting `auto` or any registered theme (previously only the
   `ZERO_THEME` env var existed).
 - "Accessibility / Appearance" section in the README documenting `NO_COLOR`, `ZERO_THEME`, `/theme`,

CONTRIBUTING.md

@@ -8,6 +8,13 @@ stabilizes. Community participation is still welcome, especially through bug
 reports, feature requests, reproduction details, logs, and discussion on existing
 issues.
 
+Questions and setup help belong in
+[GitHub Discussions](https://github.com/Gitlawb/zero/discussions) (see
+[SUPPORT.md](SUPPORT.md)), not in the issue tracker. Feature ideas start in the
+[Ideas](https://github.com/Gitlawb/zero/discussions/categories/ideas) category;
+an idea that gains traction there is the path to an approved issue and,
+eventually, an accepted PR.
+
 Please read this policy before opening a pull request. Pull requests that do not
 follow it may be closed without review.
 
@@ -33,7 +40,11 @@ unless the issue has been explicitly approved for outside contribution.
 There are three primary ways to contribute:
 
 1. Open a bug report with clear reproduction steps.
-2. Open a feature request describing the problem, use case, and expected behavior.
+2. Propose a feature in
+   [Discussions Ideas](https://github.com/Gitlawb/zero/discussions/categories/ideas),
+   describing the problem, use case, and expected behavior. A feature-request
+   issue is filed only after the idea gains traction there or a maintainer asks
+   for one.
 3. Add useful context to an existing issue, such as logs, screenshots, examples,
    affected versions, or reproduction cases.
 
@@ -46,7 +57,8 @@ All community pull requests require an approved parent issue.
 
 Before starting implementation work:
 
-1. Open an issue using the appropriate issue template.
+1. For a bug, open an issue using the bug-report template. For a feature, start
+   in Discussions Ideas; the feature-request issue comes after the discussion.
 2. Describe the bug, feature request, or functional change clearly.
 3. Wait for the core team to review the issue.
 4. Do not open a pull request unless the issue has the `issue-approved` label.
@@ -55,6 +67,28 @@ An approved issue means only that the specific issue has been accepted for work.
 It does not approve unrelated future work, future pull requests, or future issues
 from the same author. Each issue is reviewed case by case.
 
+## Contribution Volume and Batching
+
+To keep triage and review sustainable while the project stabilizes, please keep
+your contribution flow to a size the core team can realistically work through:
+
+- One issue per bug. File each defect as its own issue with its own
+  reproduction. Please do not bundle several unrelated findings into a single
+  "audit" issue; separate issues are far easier to triage, approve, and close
+  individually.
+- Keep only a few items open at a time. If you already have several issues or
+  pull requests awaiting review, let those move through the queue before opening
+  more. A large simultaneous burst from one contributor slows review for
+  everyone, even when each item is valid.
+- AI-assisted contributions are welcome, held to the same bar. Automated audits
+  and generated patches are fine, but each issue and pull request must be
+  individually verified, scoped, and reproducible before you open it. Please do
+  not post bulk machine-generated findings unfiltered.
+
+These apply to all contributors and are about review bandwidth, not the value of
+any single report. Maintainers may ask you to consolidate, split, or hold
+submissions to keep the queue manageable.
+
 ## Pull Request Requirements
 
 Before opening a community pull request, make sure all of the following are true:
@@ -133,7 +167,12 @@ Clear bug reports are the most useful way to help the project during this phase.
 
 ## Submitting a Feature Request
 
-When filing a feature request, please include:
+Feature requests start as a thread in
+[Discussions Ideas](https://github.com/Gitlawb/zero/discussions/categories/ideas),
+not as an issue. The feature-request issue form exists for the step AFTER that:
+when an idea has gained traction in Discussions or a maintainer has asked for an
+issue to track it. Whether in the discussion or the eventual issue, please
+include:
 
 - The problem you are trying to solve.
 - The behavior or functionality you are requesting.
@@ -156,5 +195,9 @@ contribution phase.
 
 ## Getting Help
 
-If you are unsure whether a change is appropriate, open an issue first and ask.
-Please keep discussion focused, specific, and respectful of maintainer time.
+General questions, setup help, and "is this a bug or my config" uncertainty all
+go to
+[Discussions Q&A](https://github.com/Gitlawb/zero/discussions/categories/q-a).
+If you are unsure whether a proposed code change is appropriate, raise it in
+Discussions Ideas or on the relevant issue first and ask. Please keep discussion
+focused, specific, and respectful of maintainer time.

Makefile

@@ -1,7 +1,7 @@
 # Zero build/test/lint targets. AGENTS.md says "Build with `make`" and "Run `make
 # lint` before opening a PR" — these targets back those instructions.
 .DEFAULT_GOAL := build
-.PHONY: build build-all test test-race vet fmt fmt-check lint tidy clean help
+.PHONY: build build-all test test-race vet fmt fmt-check lint tidy clean baseline help
 
 # Build the main CLI binary into ./zero.
 build:
@@ -40,5 +40,19 @@ clean:
 	rm -f zero
 	go clean ./...
 
+# Run the per-turn benchmark harness over the checked-in baseline manifest and
+# write the JSON result to internal/perfbench/reports/baseline.json. Requires a
+# built `zero` binary and a model; set ZERO_BENCH_MODEL (required) and
+# ZERO_BENCH_BINARY (defaults to ./zero) to configure the run. The report is
+# machine-specific and regenerated, not hand-edited.
+baseline: build
+	@if [ -z "$(ZERO_BENCH_MODEL)" ]; then echo "Set ZERO_BENCH_MODEL (and optionally ZERO_BENCH_BINARY) before running 'make baseline'"; exit 2; fi
+	@ZERO_BIN="$${ZERO_BENCH_BINARY:-./zero}"; \
+	go run ./cmd/zero-perf-bench turn \
+		--suite internal/perfbench/manifests/baseline.json \
+		--model $(ZERO_BENCH_MODEL) \
+		--binary "$$ZERO_BIN" \
+		--output internal/perfbench/reports/baseline.json
+
 help:
-	@echo "Targets: build (default), build-all, test, test-quick, vet, fmt, fmt-check, lint, tidy, clean"
+	@echo "Targets: build (default), build-all, test, test-quick, vet, fmt, fmt-check, lint, tidy, clean, baseline"

README.md

@@ -129,11 +129,18 @@ the key in the wizard:
 export OPENAI_API_KEY=sk-...
 export ANTHROPIC_API_KEY=...
 export GEMINI_API_KEY=...
+export AIMLAPI_API_KEY=...
 export LONGCAT_API_KEY=...
 export MINIMAX_API_KEY=...
 export MINIMAXI_API_KEY=...
 ```
 
+To configure AI/ML API directly, run:
+
+```bash
+zero providers setup aimlapi --set-active
+```
+
 To configure Meituan LongCat (LongCat-2.0) directly, run:
 
 ```bash
@@ -184,9 +191,11 @@ Useful controls:
 |---|---|
 | `Enter` | send the prompt |
 | `/` | open slash-command suggestions |
+| `Ctrl+X` then letter | common slash commands (e.g. `m` → `/model`; `Ctrl+X` `?` for full list) |
+| `Ctrl+P` / `Ctrl+N` | previous / next item in menus (arrows still work) |
 | `Shift+Tab` | cycle permission mode |
 | `Ctrl+B` | show/hide the sidebar |
-| `Ctrl+C` | cancel or exit |
+| `Ctrl+C` | cancel, exit, or return from a `/btw` conversation |
 
 Common slash commands:
 
@@ -196,6 +205,7 @@ Common slash commands:
 | `/spec`, `/plan` | draft and review a plan before building |
 | `/image` | attach an image for vision-capable models |
 | `/resume`, `/rewind` | continue or roll back local sessions |
+| `/btw [question]` | ask in an isolated fork without adding the side conversation to the main session |
 | `/loop` | repeat a prompt or custom `/command` on an interval (`/loop 5m /babysit-prs`) or self-paced |
 | `/compact`, `/context` | manage context usage |
 | `/permissions`, `/tools` | inspect available tools and policy |
@@ -332,7 +342,7 @@ manifest.
 | Control | Effect |
 |---|---|
 | `NO_COLOR=<anything>` | disables color output |
-| `ZERO_THEME=<name>` | selects the startup theme (`auto`, `dark`, `light`, or a color theme like `dracula`, `nord`, `gruvbox`, `tokyo-night`, `catppuccin`, `one-dark`, `solarized-dark`, `rose-pine`, `everforest`, `solarized-light`) |
+| `ZERO_THEME=<name>` | selects the startup theme (`auto`, `dark`, `light`, or a color theme like `dracula`, `nord`, `gruvbox`, `tokyo-night`, `catppuccin`, `one-dark`, `solarized-dark`, `rose-pine`, `everforest`, `neon`, `solarized-light`, `dune`) |
 | `--theme <name>` | selects the TUI theme from the CLI (same names) |
 | `/theme` | opens the theme picker inside the TUI (live preview; `/theme <name>` switches directly) |
 | `ZERO_NO_FADE=1` | disables streaming fade animation |
@@ -349,6 +359,12 @@ go run ./cmd/zero-release smoke
 go run ./cmd/zero-perf-bench
 ```
 
+Experimental: `ZERO_OPENAI_TURN_SESSION=1` enables the optimized OpenAI turn
+session (background connection prewarm + request-prefix telemetry) for headless
+`zero exec` runs against official OpenAI profiles. Off by default; `0`/`false`
+disable. A/B-benchmark it by running the same `zero-perf-bench` suite with the
+variable unset and set.
+
 ### Code Quality and Security Checks
 
 Before committing any changes, ensure all Go code quality and security checks pass. Pinned `go run` commands matching CI constraints can be used directly without prior installation:
@@ -368,6 +384,15 @@ go install github.com/golangci/golangci-lint/v2/cmd/[email protected]
 go install golang.org/x/vuln/cmd/[email protected]
 ```
 
+The installed binaries land in `$GOBIN` when it is set, otherwise in
+`$GOPATH/bin` (default `~/go/bin`). That directory must be on your `PATH` to
+run them directly. If it isn't, add it:
+
+```bash
+gobin="$(go env GOBIN)"; [ -z "$gobin" ] && gobin="$(go env GOPATH)/bin"
+case ":$PATH:" in *":$gobin:"*) ;; *) export PATH="$PATH:$gobin" ;; esac
+```
+
 ### Cross-Compile Examples
 
 ```bash
@@ -379,6 +404,7 @@ go run ./cmd/zero-release build --goos windows --goarch amd64 --output dist/zero
 
 - [Install](docs/INSTALL.md)
 - [Update flow](docs/UPDATE.md)
+- [Themes](docs/THEMES.md)
 - [Stream-JSON protocol](docs/STREAM_JSON_PROTOCOL.md)
 - [Specialists](docs/SPECIALISTS.md)
 - [GitHub Action](docs/GITHUB_ACTION.md)
@@ -386,6 +412,24 @@ go run ./cmd/zero-release build --goos windows --goarch amd64 --output dist/zero
 - [Performance](docs/PERFORMANCE.md)
 - [Agent evals](docs/AGENT_EVALS.md)
 
+## Community
+
+Questions, setup help, ideas, and sharing all live in
+[GitHub Discussions](https://github.com/Gitlawb/zero/discussions):
+
+| Category | Use it for |
+|---|---|
+| [Q&A](https://github.com/Gitlawb/zero/discussions/categories/q-a) | Setup help, provider/model configuration, "how do I" questions |
+| [Ideas](https://github.com/Gitlawb/zero/discussions/categories/ideas) | Feature proposals and design discussion before any PR |
+| [Show and tell](https://github.com/Gitlawb/zero/discussions/categories/show-and-tell) | Your skills, plugins, MCP setups, themes, and workflows |
+| [Announcements](https://github.com/Gitlawb/zero/discussions/categories/announcements) | Releases and project news from the maintainers |
+
+For a good Q&A answer fast, include `zero --version`, your OS and install
+method, the provider/model in use, and `zero doctor` output. See
+[SUPPORT.md](SUPPORT.md). Bugs belong in
+[issues](https://github.com/Gitlawb/zero/issues/new/choose); security reports
+follow [SECURITY.md](SECURITY.md), never a public thread.
+
 ## Contributing
 
 Contributions are welcome. Read [CONTRIBUTING.md](CONTRIBUTING.md), run the

README_ZH.md

@@ -234,7 +234,7 @@ zero update           检查更新版本
 | 控制 | 效果 |
 |---|---|
 | `NO_COLOR=<任意值>` | 禁用颜色输出 |
-| `ZERO_THEME=<名称>` | 选择启动主题（`auto`、`dark`、`light`，或颜色主题如 `dracula`、`nord`、`gruvbox`、`tokyo-night`、`catppuccin`、`one-dark`、`solarized-dark`、`rose-pine`、`everforest`、`solarized-light`） |
+| `ZERO_THEME=<名称>` | 选择启动主题（`auto`、`dark`、`light`，或颜色主题如 `dracula`、`nord`、`gruvbox`、`tokyo-night`、`catppuccin`、`one-dark`、`solarized-dark`、`rose-pine`、`everforest`、`neon`、`solarized-light`、`dune`） |
 | `--theme <名称>` | 从 CLI 选择 TUI 主题（相同名称） |
 | `/theme` | 在 TUI 中打开主题选择器（实时预览；`/theme <名称>` 直接切换） |
 | `ZERO_NO_FADE=1` | 禁用流式淡入动画 |
@@ -261,6 +261,7 @@ go run ./cmd/zero-release build --goos windows --goarch amd64 --output dist/zero
 
 - [安装](docs/INSTALL.md)
 - [更新流程](docs/UPDATE.md)
+- [主题](docs/THEMES.md)
 - [Stream-JSON 协议](docs/STREAM_JSON_PROTOCOL.md)
 - [专家](docs/SPECIALISTS.md)
 - [GitHub Action](docs/GITHUB_ACTION.md)

SUPPORT.md

@@ -0,0 +1,36 @@
+# Getting help with Zero
+
+## Questions, setup help, configuration
+
+Ask in [GitHub Discussions](https://github.com/Gitlawb/zero/discussions). Use
+[Q&A](https://github.com/Gitlawb/zero/discussions/categories/q-a) so answers can
+be marked and found by the next person.
+
+The fastest way to a useful answer is to include:
+
+- `zero --version` output
+- your OS (Windows, macOS, Linux) and how you installed Zero (npm, install
+  script, source)
+- the provider and model you are using (`zero providers list`)
+- `zero doctor` output for setup problems
+- the exact command you ran and the exact error text
+
+## Bugs
+
+If Zero does something wrong (crashes, wrong output, broken behavior), file a
+[bug report](https://github.com/Gitlawb/zero/issues/new/choose). If you are not
+sure whether it is a bug or a setup problem, start in Discussions and we will
+promote it to an issue if it is one.
+
+## Feature ideas
+
+Start a thread in
+[Ideas](https://github.com/Gitlawb/zero/discussions/categories/ideas). Zero is
+in controlled development (see CONTRIBUTING.md), so discussing an idea first is
+also the path to getting a PR accepted.
+
+## Security issues
+
+Never file a public issue or discussion. Report privately via
+[GitHub Security Advisories](https://github.com/Gitlawb/zero/security/advisories/new)
+(see SECURITY.md).

bin/zero.js

@@ -55,6 +55,133 @@ function localControlHelperManifest(packageRoot) {
   return JSON.stringify({ version: 1, helpers });
 }
 
+// Mirrors internal/cli/observability.go parseDoctorArgs + writeDoctorHelp so the
+// wrapper's missing-binary doctor fallback matches the Go doctor CLI surface.
+const DOCTOR_HELP = `Usage:
+  zero doctor [flags]
+
+Runs Go backend health checks for config and provider setup.
+
+Flags:
+      --json            Print JSON report
+      --connectivity    Include provider endpoint connectivity probe when available
+  -h, --help            Show this help
+`;
+
+const EXIT_USAGE = 2;
+
+function installedByBun() {
+  if (process.env.ZERO_WRAPPER_SIMULATE_BUN === '1') {
+    return true;
+  }
+  return process.execPath.includes('bun') || !!process.versions?.bun;
+}
+
+function bunRecoveryParagraph() {
+  return (
+    'You installed with Bun, which does not run dependency lifecycle scripts\n' +
+    'by default. Trust the package to run the blocked postinstall:\n' +
+    '  bun pm trust @gitlawb/zero       (project install)\n' +
+    '  bun pm -g trust @gitlawb/zero    (global install)\n' +
+    'On Bun versions without `bun pm trust`, add\n' +
+    '  "trustedDependencies": ["@gitlawb/zero"]\n' +
+    'to your project package.json and reinstall.\n' +
+    '\n'
+  );
+}
+
+function buildFromSourceParagraph() {
+  return (
+    'If this platform has no prebuilt binary, build from source:\n' +
+    'https://github.com/Gitlawb/zero (go run ./cmd/zero, requires Go 1.26+).'
+  );
+}
+
+function missingBinaryContextParagraph() {
+  return (
+    'Normally npm installs it as an optional dependency of @gitlawb/zero\n' +
+    `(@gitlawb/zero-${process.platform}-${process.arch}), and the wrapper can\n` +
+    'also download it from the GitHub Release when it is missing.'
+  );
+}
+
+function missingNativeRecoveryParagraphs(postinstallScript) {
+  const ranByBun = installedByBun();
+  return (
+    missingBinaryContextParagraph() +
+    '\n' +
+    '\n' +
+    'Things to try:\n' +
+    '  - reinstall without omitting optional dependencies:\n' +
+    '      npm install -g @gitlawb/zero\n' +
+    '  - run the downloader manually (needs write access to the package dir):\n' +
+    `      node "${postinstallScript}"\n` +
+    '\n' +
+    (ranByBun ? bunRecoveryParagraph() : '') +
+    buildFromSourceParagraph()
+  );
+}
+
+function formatGenericMissingNativeBinaryMessage(postinstallScript) {
+  return (
+    '[zero] No native binary is available for this install.\n' +
+    missingNativeRecoveryParagraphs(postinstallScript)
+  );
+}
+
+function parseDoctorArgs(args) {
+  let json = false;
+  for (const arg of args) {
+    switch (arg) {
+      case '-h':
+      case '--help':
+      case 'help':
+        return { kind: 'help' };
+      case '--json':
+        json = true;
+        break;
+      case '--connectivity':
+        break;
+      default:
+        return { kind: 'error', message: `unknown doctor flag ${JSON.stringify(arg)}` };
+    }
+  }
+  return { kind: 'run', json };
+}
+
+function missingNativeDoctorJSONReport(postinstallScript) {
+  return {
+    generatedAt: new Date().toISOString().replace(/\.\d{3}Z$/, 'Z'),
+    ok: false,
+    checks: [
+      {
+        id: 'runtime.go',
+        label: 'Go runtime',
+        status: 'fail',
+        message: 'Native zero binary is missing next to the npm wrapper.',
+        details: {
+          remedy: `node "${postinstallScript}"`,
+        },
+      },
+    ],
+  };
+}
+
+function missingNativeDoctorTextReport(postinstallScript) {
+  return (
+    'Zero doctor report (' +
+    new Date().toISOString() +
+    ')\n' +
+    'Overall: fail\n' +
+    '[fail] runtime.go - Native zero binary is missing next to the npm wrapper.\n' +
+    '  remedy: node "' +
+    postinstallScript +
+    '"\n' +
+    '\n' +
+    missingNativeRecoveryParagraphs(postinstallScript)
+  );
+}
+
 // The platform payload is a version of @gitlawb/zero itself, installed under
 // an npm: alias (see docs/NPM_PACKAGING.md). The alias name is derived from
 // process.platform/process.arch, so an unsupported platform simply fails to
@@ -114,21 +241,38 @@ function resolveNativeBinary() {
 const nativePath = resolveNativeBinary();
 
 if (!nativePath) {
-  console.error(
-    '[zero] No native binary is available for this install.\n' +
-      'Normally npm installs it as an optional dependency of @gitlawb/zero\n' +
-      `(@gitlawb/zero-${process.platform}-${process.arch}), and the wrapper can\n` +
-      'also download it from the GitHub Release when it is missing.\n' +
-      '\n' +
-      'Things to try:\n' +
-      '  - reinstall without omitting optional dependencies:\n' +
-      '      npm install -g @gitlawb/zero\n' +
-      '  - run the downloader manually (needs write access to the package dir):\n' +
-      `      node "${join(packageRoot, 'scripts', 'postinstall.mjs')}"\n` +
-      '\n' +
-      'If this platform has no prebuilt binary, build from source:\n' +
-      'https://github.com/Gitlawb/zero (go run ./cmd/zero, requires Go 1.26+).',
-  );
+  const postinstallScript = join(packageRoot, 'scripts', 'postinstall.mjs');
+
+  // `zero doctor` is the diagnostic command: when the native binary is missing
+  // it's the one invocation that must NOT bail with the generic wrapper error,
+  // because that's exactly the blind alley issue #405 reports. Instead, surface
+  // a doctor-shaped FAIL line for the runtime so the user's diagnostic finds the
+  // real cause. We branch on a literal 'doctor' subcommand only (matching `zero
+  // doctor` and `zero doctor --connectivity`), preserving the existing bail for
+  // every other invocation (exec, providers list, TUI, --version, etc.).
+  const argv = process.argv.slice(2);
+  const isDoctor = argv.length > 0 && argv[0] === 'doctor';
+  if (isDoctor) {
+    const parsed = parseDoctorArgs(argv.slice(1));
+    if (parsed.kind === 'help') {
+      process.stdout.write(DOCTOR_HELP);
+      process.exit(0);
+    }
+    if (parsed.kind === 'error') {
+      process.stderr.write(`[zero] ${parsed.message}\n`);
+      process.exit(EXIT_USAGE);
+    }
+
+    if (parsed.json) {
+      process.stdout.write(JSON.stringify(missingNativeDoctorJSONReport(postinstallScript), null, 2) + '\n');
+      process.exit(1);
+    }
+
+    process.stdout.write(missingNativeDoctorTextReport(postinstallScript) + '\n');
+    process.exit(1);
+  }
+
+  console.error(formatGenericMissingNativeBinaryMessage(postinstallScript));
   process.exit(1);
 }
 

cmd/zero-perf-bench/main.go

@@ -39,6 +39,9 @@ func run(args []string, getenv func(string) string, stdout io.Writer, stderr io.
 	if len(args) > 0 && args[0] == "tasks" {
 		return runTasksCommand(args[1:], getenv, stdout, stderr)
 	}
+	if len(args) > 0 && args[0] == "turn" {
+		return runTurnCommand(args[1:], getenv, stdout, stderr)
+	}
 	options, err := parseArgs(args, getenv)
 	if err != nil {
 		_, _ = fmt.Fprintln(stderr, err.Error())
@@ -206,6 +209,7 @@ func helpText() string {
 	return strings.Join([]string{
 		"Usage: zero-perf-bench [options]",
 		"       zero-perf-bench tasks [options]   (Terminal-Bench-style task harness; see `tasks --help`)",
+		"       zero-perf-bench turn  [options]   (per-turn tracing benchmark; see `turn --help`)",
 		"",
 		"Options:",
 		"  --iterations <n>             Measured samples to collect (default: 5)",

cmd/zero-perf-bench/main_test.go

@@ -4,6 +4,8 @@ import (
 	"bytes"
 	"strings"
 	"testing"
+
+	"github.com/Gitlawb/zero/internal/perfbench"
 )
 
 func TestParseArgsUsesCliAndEnvOverrides(t *testing.T) {
@@ -92,3 +94,18 @@ func TestHelpText(t *testing.T) {
 func emptyEnv(string) string {
 	return ""
 }
+
+func TestTurnExitCodeFailsWhenEveryTaskErrored(t *testing.T) {
+	var stderr bytes.Buffer
+	allErrored := perfbench.TurnBenchResult{TasksAttempted: 3, TasksErrored: 3}
+	if code := turnExitCode(allErrored, &stderr); code != 1 {
+		t.Fatalf("exit=%d, want 1 when every task errored", code)
+	}
+	if !strings.Contains(stderr.String(), "no accepted benchmark sample") {
+		t.Fatalf("stderr missing explanation: %q", stderr.String())
+	}
+	partial := perfbench.TurnBenchResult{TasksAttempted: 3, TasksErrored: 2}
+	if code := turnExitCode(partial, &stderr); code != 0 {
+		t.Fatalf("exit=%d, want 0 for partial errors (summary surfaces them)", code)
+	}
+}

cmd/zero-perf-bench/turn.go

@@ -0,0 +1,279 @@
+package main
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/Gitlawb/zero/internal/execprofile"
+	"github.com/Gitlawb/zero/internal/perfbench"
+)
+
+// turnOptions configures the `zero-perf-bench turn` subcommand: the per-turn
+// benchmark harness that runs ZERO headlessly with --trace, parses each turn's
+// NDJSON trace, and records per-span latency plus the top controllable latency
+// sources — the Phase 0 baseline's "do not proceed until" criterion.
+type turnOptions struct {
+	SuitePath   string
+	Model       string
+	Mode        string
+	ExecProfile string
+	SelfCorrect bool
+	Binary      string
+	Iterations  int
+	Version     string
+	Commit      string
+	Output      string
+	JSON        bool
+	DryRun      bool
+	Help        bool
+}
+
+func runTurnCommand(args []string, getenv func(string) string, stdout io.Writer, stderr io.Writer) int {
+	options, err := parseTurnArgs(args, getenv)
+	if err != nil {
+		_, _ = fmt.Fprintln(stderr, err.Error())
+		return 2
+	}
+	if options.Help {
+		_, _ = fmt.Fprint(stdout, turnHelpText())
+		return 0
+	}
+
+	set, err := perfbench.LoadTaskSet(options.SuitePath)
+	if err != nil {
+		_, _ = fmt.Fprintln(stderr, "[zero] Turn benchmark failed: "+err.Error())
+		return 1
+	}
+
+	// The dry-run path records a zero-iteration run without a binary, so the
+	// manifest loads and the report path is exercised in CI without a model.
+	if options.DryRun {
+		_, _ = fmt.Fprintln(stdout, "[zero] turn benchmark: dry run (no agent invoked)")
+		return 0
+	}
+
+	binary, err := perfbench.ResolveBinary(options.Binary)
+	if err != nil {
+		_, _ = fmt.Fprintln(stderr, "[zero] Turn benchmark failed: "+err.Error())
+		return 2
+	}
+
+	result, err := perfbench.RunTurnBench(context.Background(), set, perfbench.TurnBenchConfig{
+		Model:       options.Model,
+		Mode:        options.Mode,
+		ExecProfile: options.ExecProfile,
+		SelfCorrect: options.SelfCorrect,
+		Version:     options.Version,
+		Commit:      options.Commit,
+		Iterations:  options.Iterations,
+		Runner:      perfbench.NewTurnExecRunner(binary),
+	})
+	if err != nil {
+		_, _ = fmt.Fprintln(stderr, "[zero] Turn benchmark failed: "+err.Error())
+		return 1
+	}
+
+	if options.Output != "" {
+		if err := writeTurnReport(options.Output, result); err != nil {
+			_, _ = fmt.Fprintln(stderr, "[zero] Turn benchmark failed: "+err.Error())
+			return 1
+		}
+	}
+	if options.JSON {
+		if err := perfbench.WriteTurnBenchJSON(stdout, result); err != nil {
+			_, _ = fmt.Fprintln(stderr, "[zero] Turn benchmark failed: "+err.Error())
+			return 1
+		}
+		return turnExitCode(result, stderr)
+	}
+	_, _ = fmt.Fprintln(stdout, perfbench.FormatTurnBenchSummary(result))
+	return turnExitCode(result, stderr)
+}
+
+// turnExitCode fails the command when every attempted task errored (no
+// iteration produced an accepted benchmark sample): such a report measures
+// nothing, and exiting 0 would let a broken configuration (missing binary, bad
+// path, failing harness step) pass as a clean baseline. Partial errors keep
+// exit 0 — the summary surfaces them loudly and the surviving samples are
+// still valid measurements.
+func turnExitCode(result perfbench.TurnBenchResult, stderr io.Writer) int {
+	if result.TasksAttempted > 0 && result.TasksErrored == result.TasksAttempted {
+		_, _ = fmt.Fprintln(stderr, "[zero] Turn benchmark failed: every task errored with no accepted benchmark sample (see warnings); the report contains no valid measurements")
+		return 1
+	}
+	return 0
+}
+
+func parseTurnArgs(args []string, getenv func(string) string) (turnOptions, error) {
+	options := turnOptions{
+		Iterations: 1,
+		Version:    strings.TrimSpace(getenv("ZERO_BENCH_VERSION")),
+		Commit:     strings.TrimSpace(getenv("ZERO_BENCH_COMMIT")),
+	}
+	for index := 0; index < len(args); index++ {
+		arg := args[index]
+		flag, inlineValue := splitFlagValue(arg)
+		switch flag {
+		case "--suite":
+			value, next, err := readOptionValue(args, inlineValue, index, flag)
+			if err != nil {
+				return options, err
+			}
+			options.SuitePath = value
+			index = next
+		case "--model":
+			value, next, err := readOptionValue(args, inlineValue, index, flag)
+			if err != nil {
+				return options, err
+			}
+			options.Model = value
+			index = next
+		case "--mode":
+			value, next, err := readOptionValue(args, inlineValue, index, flag)
+			if err != nil {
+				return options, err
+			}
+			options.Mode = value
+			index = next
+		case "--exec-profile":
+			value, next, err := readOptionValue(args, inlineValue, index, flag)
+			if err != nil {
+				return options, err
+			}
+			options.ExecProfile = value
+			index = next
+		case "--binary":
+			value, next, err := readOptionValue(args, inlineValue, index, flag)
+			if err != nil {
+				return options, err
+			}
+			options.Binary = value
+			index = next
+		case "--iterations":
+			value, next, err := readOptionValue(args, inlineValue, index, flag)
+			if err != nil {
+				return options, err
+			}
+			parsed, err := parsePositiveInteger(flag, value)
+			if err != nil {
+				return options, err
+			}
+			options.Iterations = parsed
+			index = next
+		case "--version":
+			value, next, err := readOptionValue(args, inlineValue, index, flag)
+			if err != nil {
+				return options, err
+			}
+			options.Version = value
+			index = next
+		case "--commit":
+			value, next, err := readOptionValue(args, inlineValue, index, flag)
+			if err != nil {
+				return options, err
+			}
+			options.Commit = value
+			index = next
+		case "--output":
+			value, next, err := readOptionValue(args, inlineValue, index, flag)
+			if err != nil {
+				return options, err
+			}
+			options.Output = value
+			index = next
+		case "--self-correct":
+			if strings.Contains(arg, "=") {
+				return options, fmt.Errorf("%s does not accept a value", flag)
+			}
+			options.SelfCorrect = true
+		case "--json":
+			if strings.Contains(arg, "=") {
+				return options, fmt.Errorf("%s does not accept a value", flag)
+			}
+			options.JSON = true
+		case "--dry-run":
+			if strings.Contains(arg, "=") {
+				return options, fmt.Errorf("%s does not accept a value", flag)
+			}
+			options.DryRun = true
+		case "-h", "--help":
+			if strings.Contains(arg, "=") {
+				return options, fmt.Errorf("%s does not accept a value", flag)
+			}
+			options.Help = true
+		default:
+			return options, fmt.Errorf("unknown option: %s", arg)
+		}
+	}
+	if options.Help {
+		return options, nil
+	}
+	if strings.TrimSpace(options.SuitePath) == "" {
+		return options, fmt.Errorf("--suite is required")
+	}
+	if strings.TrimSpace(options.Model) == "" && !options.DryRun {
+		return options, fmt.Errorf("--model is required (or pass --dry-run)")
+	}
+	// Validate the profile here, before anything spawns: an unknown name would
+	// otherwise make every child exit with a usage error in milliseconds, and
+	// those near-zero walls would be recorded as valid latency samples in an
+	// exit-0 report — exactly the misread-as-improvement trap the harness
+	// closed for spawn failures. Normalizing to the catalog name also keeps
+	// the stamped execProfile canonical (Lookup is case-insensitive), so two
+	// captures of the same posture always compare equal.
+	if raw := strings.TrimSpace(options.ExecProfile); raw != "" {
+		profile, ok := execprofile.Lookup(raw)
+		if !ok {
+			return options, fmt.Errorf("unknown execution profile %q for --exec-profile. Valid profiles: %s", raw, strings.Join(execprofile.Names(), ", "))
+		}
+		options.ExecProfile = profile.Name
+	}
+	return options, nil
+}
+
+func writeTurnReport(path string, result perfbench.TurnBenchResult) error {
+	if dir := filepath.Dir(path); dir != "" {
+		if err := os.MkdirAll(dir, 0o755); err != nil {
+			return err
+		}
+	}
+	var buffer bytes.Buffer
+	if err := perfbench.WriteTurnBenchJSON(&buffer, result); err != nil {
+		return err
+	}
+	return os.WriteFile(path, buffer.Bytes(), 0o644)
+}
+
+func turnHelpText() string {
+	return strings.Join([]string{
+		"Usage: zero-perf-bench turn [options]",
+		"",
+		"Runs ZERO headlessly with --trace against a per-turn benchmark task set and",
+		"records per-span latency plus the top controllable latency sources (the",
+		"Phase 0 baseline's \"do not proceed until\" criterion). Each task is a fresh",
+		"`zero exec` process, so iterations are cold-start samples; a warm path needs",
+		"an in-process runner (future work).",
+		"",
+		"Options:",
+		"  --suite <path>      Task set JSON file (required)",
+		"  --model <model>     Model to run (required unless --dry-run)",
+		"  --mode <name>       Exec mode preset to apply",
+		"  --exec-profile <name>",
+		"                      Execution profile for every task (fast|balanced|thorough);",
+		"                      forwarded to zero exec and stamped into the result",
+		"  --self-correct      Enable the post-edit verify-and-correct loop",
+		"  --binary <path>     Path to the `zero` binary (default: zero on PATH / repo root)",
+		"  --iterations <n>    Times to run each task (default: 1)",
+		"  --version <v>       Record the ZERO version (default: $ZERO_BENCH_VERSION)",
+		"  --commit <sha>      Record the ZERO commit (default: $ZERO_BENCH_COMMIT)",
+		"  --output <path>     Write the JSON result to path",
+		"  --json              Print only the JSON result",
+		"  --dry-run           Load the manifest and exit without invoking the agent",
+		"  -h, --help          Show this help",
+	}, "\n") + "\n"
+}

cmd/zero-perf-bench/turn_test.go

@@ -0,0 +1,65 @@
+package main
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestParseTurnArgsExecProfile(t *testing.T) {
+	getenv := func(string) string { return "" }
+	options, err := parseTurnArgs([]string{
+		"--suite", "suite.json",
+		"--model", "m",
+		"--exec-profile", "fast",
+	}, getenv)
+	if err != nil {
+		t.Fatalf("parseTurnArgs: %v", err)
+	}
+	if options.ExecProfile != "fast" {
+		t.Fatalf("ExecProfile = %q, want fast", options.ExecProfile)
+	}
+
+	// Inline form.
+	options, err = parseTurnArgs([]string{
+		"--suite=suite.json",
+		"--model=m",
+		"--exec-profile=thorough",
+	}, getenv)
+	if err != nil {
+		t.Fatalf("parseTurnArgs inline: %v", err)
+	}
+	if options.ExecProfile != "thorough" {
+		t.Fatalf("ExecProfile = %q, want thorough", options.ExecProfile)
+	}
+}
+
+// The bench validates the profile BEFORE spawning anything: an unknown name
+// would otherwise make every child exit with a usage error in milliseconds
+// and record those near-zero walls as valid latency samples in an exit-0
+// report. Lookup normalization also keeps the stamped name canonical so two
+// captures of the same posture compare equal.
+func TestParseTurnArgsExecProfileValidatesAndNormalizes(t *testing.T) {
+	getenv := func(string) string { return "" }
+
+	options, err := parseTurnArgs([]string{
+		"--suite", "suite.json", "--model", "m", "--exec-profile", "FAST",
+	}, getenv)
+	if err != nil {
+		t.Fatalf("parseTurnArgs: %v", err)
+	}
+	if options.ExecProfile != "fast" {
+		t.Fatalf("ExecProfile = %q, want the canonical fast", options.ExecProfile)
+	}
+
+	_, err = parseTurnArgs([]string{
+		"--suite", "suite.json", "--model", "m", "--exec-profile", "blanced",
+	}, getenv)
+	if err == nil {
+		t.Fatal("an unknown profile must fail parse, before anything spawns")
+	}
+	for _, name := range []string{"balanced", "fast", "thorough"} {
+		if !strings.Contains(err.Error(), name) {
+			t.Fatalf("error must list %q, got %q", name, err.Error())
+		}
+	}
+}

docs/EXTENDING.md

@@ -102,14 +102,24 @@ The full format spec (frontmatter fields, tool scopes, prompt conventions) is in
 
 Skills are markdown instruction packs the agent can pull in on demand. Each skill is a directory containing a `SKILL.md`. Standalone project skill directories are not supported in this version (shared project-wide skills must go in `AGENTS.md` or as a hook). However, project plugins (section 6) may bundle skills, which are merged into the active run.
 
-Discovery root: `$ZERO_SKILLS_DIR` → `$XDG_DATA_HOME/zero/skills` → `~/.local/share/zero/skills/`. A missing directory is fine — Zero just reports "no skills".
+Discovery roots (earlier wins on name collisions):
+
+1. **Primary Zero dir** — `$ZERO_SKILLS_DIR` if set, else `$XDG_DATA_HOME/zero/skills`, else `~/.local/share/zero/skills/`
+2. **Shared multi-agent dir** — `~/.agents/skills/` when present (read-only discovery; never an install target)
+3. **Plugin skill roots** — skills bundled by active plugins (section 6)
+
+A missing directory is fine — Zero just omits it. Management commands (`zero skills add` / `remove` / `lock`) always write to the primary Zero dir only; `list` / `info` search primary + `~/.agents/skills`.
 
 ```text
-~/.local/share/zero/skills/
+~/.local/share/zero/skills/          # primary (install/remove/lock target)
   run-benchmarks/
     SKILL.md
   write-changelog/
     SKILL.md
+
+~/.agents/skills/                    # optional shared multi-agent root
+  shared-review/
+    SKILL.md
 ```
 
 `SKILL.md` format:
@@ -126,9 +136,9 @@ description: Run the project's benchmark suite and summarize the deltas.
 3. Report any regression > 5% with the function name and the previous value.
 ```
 
-Only `name` and `description` are recognized in the frontmatter today. The `name` defaults to the directory name. Within a single skills root, duplicate names are resolved by lexicographic directory order. During an agent run, Zero loads the default skills directory before plugin skill roots; earlier roots win name collisions silently. Plugin-declared skills (section 6) are merged into the active agent run at plugin activation time, so bundled skills appear in the available skills list and can be loaded with the `skill` tool.
+Only `name` and `description` are recognized in the frontmatter today. The `name` defaults to the directory name. Within a single skills root, duplicate names are resolved by lexicographic directory order. Across roots, Zero loads the primary directory first, then `~/.agents/skills`, then plugin skill roots; earlier roots win name collisions. Plugin-declared skills (section 6) are merged into the active agent run at plugin activation time, so bundled skills appear in the available skills list and can be loaded with the `skill` tool.
 
-The `skill` core tool lets the agent load any discovered skill by name.
+The `skill` tool lets the agent load any discovered skill by name (primary, agents, or plugin).
 
 ## 4. Hooks
 
@@ -240,10 +250,13 @@ OAuth server names ending in `.<32 hex chars>` are reserved for token storage.
 
 ```bash
 zero serve --mcp
+zero serve --mcp -C /path/to/workspace
+zero serve --mcp --add-dir /path/to/extra
 ```
 
 The server speaks MCP over stdio. Configure it from the receiving side as a `stdio` server whose command is `zero serve --mcp`.
 
+`-C/--cwd` sets the workspace root exposed as MCP resources and used by core tools. `--add-dir` (repeatable) widens that resource/tool scope beyond the workspace without granting the sandbox temp roots used by interactive runs.
 ## 6. Plugins
 
 A plugin is a self-contained directory that bundles tools, hooks, and skills for one capability. Plugins live at:

docs/HOW_ZERO_WORKS.md

@@ -272,7 +272,8 @@ sequenceDiagram
         Agent->>Tool: execute(ctx, args)
         Tool-->>Agent: output, error, metadata
         Agent->>Hooks: afterTool hooks
-        Agent->>Agent: redact, truncate, classify success/failure
+        Agent->>Agent: redact secrets, apply semantic output budget, enforce byte ceiling
+        Agent->>Agent: classify success/failure
         Agent-->>Surface: OnToolResult callback
         Agent->>Transcript: append tool result message
     end
@@ -604,10 +605,22 @@ flowchart TD
     Prompt -- Yes --> Decision[Permission callback]
     Prompt -- No --> Run[Registry.RunWithOptions]
     Decision --> Run
-    Run --> Redact[Redact secrets + enforce output ceiling]
-    Redact --> Message[Return tool result to model]
+    Run --> Redact[Redact secrets]
+    Redact --> Budget[Token-aware semantic output budget]
+    Budget --> Ceiling[Existing hard byte ceiling]
+    Ceiling --> Message[Return one tool result to model]
 ```
 
+Oversized results use deterministic, provider-neutral estimated-token budgets.
+Policies retain useful structure for files, search matches, tests, process logs,
+diffs, and worker conclusions; tools without a declared category use a UTF-8-safe
+head/tail fallback. The estimate is intentionally conservative for non-ASCII
+text and is not exact provider tokenization. Existing byte ceilings remain the
+authoritative safety limit. When the existing spill mechanism can persist the
+complete redacted text received by the budgeting layer, the result includes its
+safe spill reference. This does not imply capture of subprocess bytes already
+discarded by a tool's established internal buffer.
+
 Core tool groups include:
 
 - **Read-only tools**: file reads, directory listing, glob, grep, LSP navigation,
@@ -733,9 +746,10 @@ flowchart TD
 - **Skills** are instruction packs the model can load on demand.
 - **Specialists** are sub-agents callable through the `Task` tool.
 - **MCP servers** contribute external tools.
-- **Plugins** can add tools, hooks, and skill roots. Bootstrap merges plugin skill
-  roots into the runtime skill tool and prompt-visible skill list; the base
-  `internal/skills` scanner still scans one root at a time.
+- **Plugins** can add tools, hooks, and skill roots. Bootstrap always registers a
+  multi-root skill tool: primary Zero skills dir, optional `~/.agents/skills`,
+  then plugin skill roots (earlier wins). `internal/skills` owns that merge via
+  `LoadFromRoots` / `DiscoveryRoots`; single-root `Load` remains for install/write.
 - **Hooks** can observe or block tool lifecycle events.
 
 ## End-to-End Data Flow

docs/THEMES.md

@@ -0,0 +1,39 @@
+# TUI Themes
+
+Zero's TUI ships a set of built-in color themes. Pick one with `--theme <name>`,
+the `ZERO_THEME` environment variable, or the `/theme <name>` command while
+running. `auto` (the default) follows the terminal's detected background.
+
+Run `/theme` with no argument to open a picker: move through the list to
+live-preview each theme, press Enter to apply the highlighted one, or Esc to
+cancel and restore the previously active theme. Run `/theme list` to print
+the active theme and the registered names without opening the picker.
+
+## Dune (`dune`)
+
+A warm sand-and-cream palette: sand/cream surface, charcoal ink, and a soft
+amber accent.
+
+## Neon (`neon`)
+
+A neon-on-black palette: pitch-black surface, bright green ink, and a cyan accent.
+
+## Adding a theme
+
+Every theme is a `palette` (a table of color hex tokens) plus one entry in
+`themeRegistry`, both in `internal/tui/theme_palettes.go`. `buildTheme` in
+`internal/tui/theme.go` turns a `palette` into the resolved `lipgloss.Style`
+set every renderer reads from the active `zeroTheme`. Adding a theme means
+adding a new `palette{...}` literal, a `themeRegistry` entry, and test
+coverage for the new palette (see below).
+
+Registry-wide tests in `internal/tui/theme_select_test.go` assert the basic
+WCAG AA text tokens, the gray-ramp order, the diff word-span pairs, and the
+selected-row band for every entry. The rendered-surface invariants beyond
+those (permission surfaces, selected-row secondary text, diff gutters, and
+the xterm-256 downsampling checks) are asserted per palette, not against the
+whole registry: `TestExtendedThemeContrastInvariants` and
+`TestExtendedThemeANSI256Contrast` enumerate the palettes they cover. A new
+theme must be added to those tests (or given equivalent palette-specific
+assertions), or CI can stay green while its permission, selected-row, and
+diff surfaces ship unreadable.

go.mod

@@ -3,9 +3,9 @@ module github.com/Gitlawb/zero
 go 1.26.5
 
 require (
-	charm.land/bubbles/v2 v2.1.0
-	charm.land/bubbletea/v2 v2.0.7
-	charm.land/lipgloss/v2 v2.0.4
+	charm.land/bubbles/v2 v2.1.1
+	charm.land/bubbletea/v2 v2.0.8
+	charm.land/lipgloss/v2 v2.0.5
 	github.com/alecthomas/chroma/v2 v2.27.0
 	github.com/atotto/clipboard v0.1.4
 	github.com/aymanbagabas/go-udiff v0.4.1
@@ -14,18 +14,18 @@ require (
 	github.com/charmbracelet/x/term v0.2.2
 	github.com/coder/websocket v1.8.15
 	github.com/ledongthuc/pdf v0.0.0-20250511090121-5959a4027728
-	golang.org/x/sys v0.46.0
+	golang.org/x/sys v0.47.0
 	mvdan.cc/sh/v3 v3.13.1
 )
 
 require (
-	github.com/charmbracelet/ultraviolet v0.0.0-20260615092913-2399af76d5b1 // indirect
+	github.com/charmbracelet/ultraviolet v0.0.0-20260703014108-f5a850f9c2b7 // indirect
 	github.com/charmbracelet/x/exp/golden v0.0.0-20260615092313-b57e5e6d29bb // indirect
 	github.com/charmbracelet/x/termios v0.1.1 // indirect
 	github.com/charmbracelet/x/windows v0.2.2 // indirect
 	github.com/clipperhouse/displaywidth v0.11.0 // indirect
 	github.com/clipperhouse/uax29/v2 v2.7.0 // indirect
-	github.com/dlclark/regexp2/v2 v2.2.1 // indirect
+	github.com/dlclark/regexp2/v2 v2.5.0 // indirect
 	github.com/go-quicktest/qt v1.102.0 // indirect
 	github.com/lucasb-eyer/go-colorful v1.4.0 // indirect
 	github.com/mattn/go-runewidth v0.0.24 // indirect
@@ -34,5 +34,5 @@ require (
 	github.com/rogpeppe/go-internal v1.15.0 // indirect
 	github.com/xo/terminfo v0.0.0-20220910002029-abceb7e1c41e // indirect
 	golang.org/x/exp v0.0.0-20260611194520-c48552f49976 // indirect
-	golang.org/x/sync v0.21.0 // indirect
+	golang.org/x/sync v0.22.0 // indirect
 )

go.sum

@@ -1,9 +1,9 @@
-charm.land/bubbles/v2 v2.1.0 h1:YSnNh5cPYlYjPxRrzs5VEn3vwhtEn3jVGRBT3M7/I0g=
-charm.land/bubbles/v2 v2.1.0/go.mod h1:l97h4hym2hvWBVfmJDtrEHHCtkIKeTEb3TTJ4ZOB3wY=
-charm.land/bubbletea/v2 v2.0.7 h1:7qw2tTAVar7m7klOPBYfTB0mniv/RuexsYwMRNxSeL0=
-charm.land/bubbletea/v2 v2.0.7/go.mod h1:DGW2q8gvzHnOpMpZTORs0aySVHCox5C+2Svk0fci1qs=
-charm.land/lipgloss/v2 v2.0.4 h1:lcPeVtcp23SNra7lHy8iYE4UC2aIipVQ47sbGyyxR5Q=
-charm.land/lipgloss/v2 v2.0.4/go.mod h1:0653x8epbZSzdDfO/XPS1a/uYPOBeSsCssOpJOqDzik=
+charm.land/bubbles/v2 v2.1.1 h1:7r55WzBxpo/R3z98hGmY7KKPd3ET6vsf0Fb9sDHOV60=
+charm.land/bubbles/v2 v2.1.1/go.mod h1:GE6M31gaWZVXzGw73OeuTTgy4lX+OtkH0E5ymnNsHxo=
+charm.land/bubbletea/v2 v2.0.8 h1:SxTJMhCAI3lbPmy4SgX5LWZ24AdINr4I6UEqzZvYJuY=
+charm.land/bubbletea/v2 v2.0.8/go.mod h1:2SkdgoTXluXJHOUwAoRlRXF/28vklb1rFl6GcgV1/ss=
+charm.land/lipgloss/v2 v2.0.5 h1:kbNxgeeUOYv5J0YdpxFjfvf3dFvqH8Aci4zB6xqFtrY=
+charm.land/lipgloss/v2 v2.0.5/go.mod h1:9oqhxt4yxIMe6q5A4kHr44DremZk7J9UNh74GlWa5nc=
 github.com/alecthomas/assert/v2 v2.11.0 h1:2Q9r3ki8+JYXvGsDyBXwH3LcJ+WK5D0gc5E8vS6K3D0=
 github.com/alecthomas/assert/v2 v2.11.0/go.mod h1:Bze95FyfUr7x34QZrjL+XP+0qgp/zg8yS+TtBj1WA3k=
 github.com/alecthomas/chroma/v2 v2.27.0 h1:FodwmyOBgJULFYmDqibcp9pvfDLWdtPRh9v/r5BXYZs=
@@ -16,8 +16,8 @@ github.com/aymanbagabas/go-udiff v0.4.1 h1:OEIrQ8maEeDBXQDoGCbbTTXYJMYRCRO1fnodZ
 github.com/aymanbagabas/go-udiff v0.4.1/go.mod h1:0L9PGwj20lrtmEMeyw4WKJ/TMyDtvAoK9bf2u/mNo3w=
 github.com/charmbracelet/colorprofile v0.4.3 h1:QPa1IWkYI+AOB+fE+mg/5/4HRMZcaXex9t5KX76i20Q=
 github.com/charmbracelet/colorprofile v0.4.3/go.mod h1:/zT4BhpD5aGFpqQQqw7a+VtHCzu+zrQtt1zhMt9mR4Q=
-github.com/charmbracelet/ultraviolet v0.0.0-20260615092913-2399af76d5b1 h1:4+r3uOJ69ueRBt4okgEfWZeXs3BD36HcDBmOIAUlETk=
-github.com/charmbracelet/ultraviolet v0.0.0-20260615092913-2399af76d5b1/go.mod h1:f/jRa757WUmaOZrbPspXymbg/GnbF+rwe4OLsG7aXYo=
+github.com/charmbracelet/ultraviolet v0.0.0-20260703014108-f5a850f9c2b7 h1:3FmWoGNWK4STvqg0O0Aeav2T7rodWJAPeF0QpH+8gFw=
+github.com/charmbracelet/ultraviolet v0.0.0-20260703014108-f5a850f9c2b7/go.mod h1:f/jRa757WUmaOZrbPspXymbg/GnbF+rwe4OLsG7aXYo=
 github.com/charmbracelet/x/ansi v0.11.7 h1:kzv1kJvjg2S3r9KHo8hDdHFQLEqn4RBCb39dAYC84jI=
 github.com/charmbracelet/x/ansi v0.11.7/go.mod h1:9qGpnAVYz+8ACONkZBUWPtL7lulP9No6p1epAihUZwQ=
 github.com/charmbracelet/x/exp/golden v0.0.0-20260615092313-b57e5e6d29bb h1:m1Uub9uM7meZ8ofVyeRfK7M/knCi3sF2gKn9kldVW0I=
@@ -34,8 +34,8 @@ github.com/clipperhouse/uax29/v2 v2.7.0 h1:+gs4oBZ2gPfVrKPthwbMzWZDaAFPGYK72F0NJ
 github.com/clipperhouse/uax29/v2 v2.7.0/go.mod h1:EFJ2TJMRUaplDxHKj1qAEhCtQPW2tJSwu5BF98AuoVM=
 github.com/coder/websocket v1.8.15 h1:6B2JPeOGlpff2Uz6vOEH1Vzpi0iUz20A+lPVhPHtNUA=
 github.com/coder/websocket v1.8.15/go.mod h1:NX3SzP+inril6yawo5CQXx8+fk145lPDC6pumgx0mVg=
-github.com/dlclark/regexp2/v2 v2.2.1 h1:mf4KkFUj0gJuarK8P+LgiS+Lit7m9N1yAwEfPbee7R0=
-github.com/dlclark/regexp2/v2 v2.2.1/go.mod h1:avUrQvPaLz2DrFNHJF0taWAFFX2C1GMSSoeiqFjcBmU=
+github.com/dlclark/regexp2/v2 v2.5.0 h1:liNiWIPCvCh5HBcYfsjd+P16AG79fwd6T1Toy2gOtEA=
+github.com/dlclark/regexp2/v2 v2.5.0/go.mod h1:avUrQvPaLz2DrFNHJF0taWAFFX2C1GMSSoeiqFjcBmU=
 github.com/go-quicktest/qt v1.102.0 h1:HSQxCeh5YZH3EL3W39ixjtyaEhcWSXQHtHnMBzSs474=
 github.com/go-quicktest/qt v1.102.0/go.mod h1:p4lGIVX+8Wa6ZPNDvqcxq36XpUDLh42FLetFU7odllI=
 github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
@@ -62,9 +62,9 @@ github.com/xo/terminfo v0.0.0-20220910002029-abceb7e1c41e h1:JVG44RsyaB9T2KIHavM
 github.com/xo/terminfo v0.0.0-20220910002029-abceb7e1c41e/go.mod h1:RbqR21r5mrJuqunuUZ/Dhy/avygyECGrLceyNeo4LiM=
 golang.org/x/exp v0.0.0-20260611194520-c48552f49976 h1:X8Hz2ImujgbmetVuW+w2YkyZChE3cBpZi2P158rTG9M=
 golang.org/x/exp v0.0.0-20260611194520-c48552f49976/go.mod h1:vnf4pv9iKZXY58sQE1L86zmNWJ4159e1RkcWiLCkeEY=
-golang.org/x/sync v0.21.0 h1:HLII4xRRTtCRkxYp4HNFF0Js/Og6q2i++KXbg0gHCwM=
-golang.org/x/sync v0.21.0/go.mod h1:9xrNwdLfx4jkKbNva9FpL6vEN7evnE43NNNJQ2LF3+0=
-golang.org/x/sys v0.46.0 h1:noSf2Fq6F8DBgS+LysIkx7rIExoNHJsxOAtPp4rthXw=
-golang.org/x/sys v0.46.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
+golang.org/x/sync v0.22.0 h1:SZjpbeLmrCk4xhRSZFNZW5gFUeCeFgjekvI/+gfScek=
+golang.org/x/sync v0.22.0/go.mod h1:9xrNwdLfx4jkKbNva9FpL6vEN7evnE43NNNJQ2LF3+0=
+golang.org/x/sys v0.47.0 h1:o7XGOvZQCADBQQ4Y7VNq2dRWQR7JmOUW8Kxx4ZsNgWs=
+golang.org/x/sys v0.47.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
 mvdan.cc/sh/v3 v3.13.1 h1:DP3TfgZhDkT7lerUdnp6PTGKyxxzz6T+cOlY/xEvfWk=
 mvdan.cc/sh/v3 v3.13.1/go.mod h1:lXJ8SexMvEVcHCoDvAGLZgFJ9Wsm2sulmoNEXGhYZD0=

internal/agent/ask_user_test.go

@@ -141,9 +141,11 @@ func TestRunAskUserCancellationAbortsRun(t *testing.T) {
 	registry := registryWithAskUser()
 	args := `{"questions":[{"question":"Which framework?"}]}`
 	provider := providerCallingAskUserThenAnswer(args, "done")
+	var toolResults []ToolResult
 
 	result, err := Run(context.Background(), "clarify", provider, Options{
-		Registry: registry,
+		Registry:     registry,
+		OnToolResult: func(result ToolResult) { toolResults = append(toolResults, result) },
 		OnAskUser: func(_ context.Context, _ AskUserRequest) (AskUserResponse, error) {
 			return AskUserResponse{}, context.Canceled
 		},
@@ -158,6 +160,9 @@ func TestRunAskUserCancellationAbortsRun(t *testing.T) {
 	if len(provider.requests) != 1 {
 		t.Fatalf("expected the run to stop after the canceled ask_user (1 turn), got %d", len(provider.requests))
 	}
+	if len(toolResults) != 1 || toolResults[0].ToolCallID == "" {
+		t.Fatalf("cancellation must emit exactly one result for the call, got %#v", toolResults)
+	}
 	// The recorded tool result must reflect cancellation, not a synthetic answer.
 	var toolMsg string
 	for _, m := range result.Messages {

internal/agent/compaction.go

@@ -6,6 +6,7 @@ import (
 	"errors"
 	"strings"
 
+	"github.com/Gitlawb/zero/internal/trace"
 	"github.com/Gitlawb/zero/internal/zeroruntime"
 )
 
@@ -55,6 +56,10 @@ type CompactionOptions struct {
 	// injected so Compact stays pure and testable; the agent loop wires it to a
 	// real provider call.
 	Summarize func(toSummarize []zeroruntime.Message) (string, error)
+	// taskState is a snapshot supplied by the running agent. Its immutable
+	// objective is always preserved; mutable fields are admitted only when its
+	// plan projection still matches the transcript.
+	taskState *taskStateSnapshot
 }
 
 // CompactionResult is the metadata-bearing result returned by CompactMessages.
@@ -219,7 +224,7 @@ func CompactMessages(messages []zeroruntime.Message, opts CompactionOptions) (Co
 
 	// Preserve structured state (active plan + loaded skills) from the elided
 	// middle verbatim, so it is not lost or paraphrased away by the prose summary.
-	content := appendPreservedState(summaryLabel+"\n"+summary, middle)
+	content := appendPreservedState(summaryLabel+"\n"+summary, middle, opts.taskState)
 
 	compacted := make([]zeroruntime.Message, 0, systemEnd+1+(len(messages)-boundary))
 	compacted = append(compacted, messages[:systemEnd]...)
@@ -325,6 +330,7 @@ type compactionState struct {
 	// OnText is deliberately NOT forwarded (compaction stays invisible to the user),
 	// but its token COST must still be counted so usage reports and budgets include it.
 	onUsage func(Usage)
+	task    *taskState
 
 	// calibrationRatio scales the raw byte/4 token estimate toward the provider's
 	// real prompt-token count. ApproxTextTokens over-counts code-heavy content by
@@ -364,13 +370,15 @@ func (state *compactionState) calibratedTokens(raw int) int {
 	return int(float64(raw) * state.calibrationRatio)
 }
 
-func newCompactionState(options Options) *compactionState {
-	return &compactionState{
+func newCompactionState(options Options, task *taskState) *compactionState {
+	state := &compactionState{
 		enabled:      options.ContextWindow > 0,
 		threshold:    compactionThreshold(options.ContextWindow),
 		preserveLast: options.CompactionPreserveLast,
 		onUsage:      options.OnUsage,
+		task:         task,
 	}
+	return state
 }
 
 // maybeCompact runs proactive compaction at the top of a turn. It returns the
@@ -417,6 +425,7 @@ func (state *compactionState) maybeCompact(
 	compacted, err := Compact(messages, CompactionOptions{
 		PreserveLast: state.preserveLast,
 		Summarize:    summarizeClosure(ctx, provider, state.onUsage),
+		taskState:    state.task.snapshotForCompaction(messages),
 	})
 	if err != nil {
 		// Summarizer failed: keep the original history. The reactive path (or a
@@ -430,6 +439,12 @@ func (state *compactionState) maybeCompact(
 		state.lowWaterMark = size
 		return messages
 	}
+	// Only count a compaction when it actually shrank the history, so the
+	// compaction counter reflects real context reductions rather than paid
+	// no-ops that left the token budget untouched.
+	if r := trace.FromContext(ctx); r != nil {
+		r.Counter(trace.CounterCompactionCount, 1)
+	}
 	state.lowWaterMark = newSize
 	return compacted
 }
@@ -461,6 +476,7 @@ func (state *compactionState) recover(
 	result, compactErr := Compact(messages, CompactionOptions{
 		PreserveLast: state.preserveLast,
 		Summarize:    summarizeClosure(ctx, provider, state.onUsage),
+		taskState:    state.task.snapshotForCompaction(messages),
 	})
 	if compactErr != nil {
 		// A genuine compaction attempt was made (and failed): the budget is spent
@@ -479,7 +495,11 @@ func (state *compactionState) recover(
 	// one-shot budget now so a provider that keeps returning context-limit errors
 	// after a successful compaction can't loop forever. Store the low-water mark in
 	// the SAME combined (messages + tool-defs) domain maybeCompact uses, so the
-	// proactive shrink-guard compares like with like.
+	// proactive shrink-guard compares like with like. Count it now that the shrink
+	// is confirmed, so the counter mirrors maybeCompact's real-reduction policy.
+	if r := trace.FromContext(ctx); r != nil {
+		r.Counter(trace.CounterCompactionCount, 1)
+	}
 	state.reactiveAttempted = true
 	state.lowWaterMark = state.calibratedTokens(estimateTokens(result) + estimateToolDefTokens(tools))
 	return result, true, nil

internal/agent/compaction_preserve.go

@@ -30,6 +30,10 @@ const (
 const (
 	maxRecentEdits   = 20
 	maxEditNoteBytes = 160
+	// maxTaskObjectiveBytes keeps the original objective recognizable after
+	// compaction without allowing an unusually large prompt to recreate the
+	// context pressure the compaction just removed.
+	maxTaskObjectiveBytes = 512
 )
 
 const (
@@ -76,32 +80,14 @@ func extractLatestPlan(messages []zeroruntime.Message) string {
 // ({"plan":[{content,status,...}]}) as terse status-tagged bullet lines. Returns
 // "" on malformed arguments or an empty plan.
 func formatPlanArguments(arguments string) string {
-	var parsed struct {
-		Plan []struct {
-			Content string `json:"content"`
-			Step    string `json:"step"`
-			Status  string `json:"status"`
-			Notes   string `json:"notes"`
-		} `json:"plan"`
-	}
-	if err := json.Unmarshal([]byte(strings.TrimSpace(arguments)), &parsed); err != nil {
+	plan, ok := parseTaskPlan(arguments)
+	if !ok {
 		return ""
 	}
-	lines := make([]string, 0, len(parsed.Plan))
-	for _, item := range parsed.Plan {
-		content := strings.TrimSpace(item.Content)
-		if content == "" {
-			content = strings.TrimSpace(item.Step)
-		}
-		if content == "" {
-			continue
-		}
-		status := strings.TrimSpace(item.Status)
-		if status == "" {
-			status = "pending"
-		}
-		line := "- [" + status + "] " + content
-		if notes := strings.TrimSpace(item.Notes); notes != "" {
+	lines := make([]string, 0, len(plan))
+	for _, item := range plan {
+		line := "- [" + item.Status + "] " + item.Content
+		if notes := item.Notes; notes != "" {
 			line += "\n  Notes: " + notes
 		}
 		lines = append(lines, line)
@@ -431,12 +417,25 @@ func capBody(body string) string {
 // preservedState is the JSON shape of the carried-across-compaction block.
 type preservedState struct {
 	Plan                string                 `json:"plan,omitempty"`
+	Task                *preservedTaskState    `json:"task,omitempty"`
 	RecentEdits         []preservedEdit        `json:"recent_edits,omitempty"`
 	Tools               []preservedTool        `json:"tools,omitempty"`
 	Skills              []preservedSkill       `json:"skills,omitempty"`
 	ProjectInstructions []preservedInstruction `json:"project_instructions,omitempty"`
 }
 
+type preservedTaskState struct {
+	Objective           string     `json:"objective"`
+	Status              taskStatus `json:"status,omitempty"`
+	Pending             int        `json:"pending,omitempty"`
+	InProgress          int        `json:"in_progress,omitempty"`
+	Completed           int        `json:"completed,omitempty"`
+	Failed              int        `json:"failed,omitempty"`
+	VerificationPassed  int        `json:"verification_passed,omitempty"`
+	VerificationFailed  int        `json:"verification_failed,omitempty"`
+	VerificationOutcome Outcome    `json:"verification_outcome,omitempty"`
+}
+
 type preservedEdit struct {
 	Path string `json:"path"`
 	Note string `json:"note,omitempty"`
@@ -464,8 +463,27 @@ type preservedInstruction struct {
 // may live only inside the injected summary message, which on a later compaction
 // lands in middle with no real tool calls left to extract. Fresh tool calls and
 // instruction blocks override the carried-forward copy by name/source.
-func appendPreservedState(summary string, middle []zeroruntime.Message) string {
+func appendPreservedState(summary string, middle []zeroruntime.Message, taskSnapshot *taskStateSnapshot) string {
 	priorState := parsePreservedStateBlock(latestSummaryContent(middle))
+	task := priorState.Task
+	if taskSnapshot != nil {
+		task = &preservedTaskState{
+			Objective: capTaskObjective(taskSnapshot.Objective),
+		}
+		// Plan parity corroborates only the mutable task projection. The objective
+		// comes directly from the run prompt and is immutable, so it must survive
+		// even after compaction removes the plan tool call needed for comparison.
+		if taskSnapshot.PlanParity == taskPlanParityMatch {
+			task.Status = taskSnapshot.Status
+			task.Pending = taskSnapshot.Plan.Pending
+			task.InProgress = taskSnapshot.Plan.InProgress
+			task.Completed = taskSnapshot.Plan.Completed
+			task.Failed = taskSnapshot.Plan.Failed
+			task.VerificationPassed = taskSnapshot.Verification.Passed
+			task.VerificationFailed = taskSnapshot.Verification.Failed
+			task.VerificationOutcome = taskSnapshot.Verification.LastOutcome
+		}
+	}
 
 	// Plan: a fresh update_plan in middle is authoritative; otherwise carry the
 	// plan preserved by an earlier compaction.
@@ -493,12 +511,25 @@ func appendPreservedState(summary string, middle []zeroruntime.Message) string {
 		projectInstructionEntries(middle),
 	)
 
-	if block := formatPreservedState(plan, edits, tools, skills, instructions); block != "" {
+	if block := formatPreservedState(plan, task, edits, tools, skills, instructions); block != "" {
 		summary += "\n\n" + block
 	}
 	return summary
 }
 
+func capTaskObjective(objective string) string {
+	objective = strings.TrimSpace(objective)
+	if len(objective) <= maxTaskObjectiveBytes {
+		return objective
+	}
+	const suffix = "…"
+	limit := maxTaskObjectiveBytes - len(suffix)
+	for limit > 0 && !utf8.RuneStart(objective[limit]) {
+		limit--
+	}
+	return strings.TrimSpace(objective[:limit]) + suffix
+}
+
 // mergeRecentEdits overlays fresh edits onto edits preserved by an earlier
 // compaction. Unlike mergeSkillEntries (which keeps refreshed entries in their
 // original slot), a path touched again by a fresh edit MOVES to the newest
@@ -555,11 +586,11 @@ func preservedEditsToEntries(edits []preservedEdit) []skillEntry {
 
 // formatPreservedState renders state as the labelled, single-line
 // JSON block. Returns "" when there is nothing to preserve.
-func formatPreservedState(plan string, edits, tools, skills, instructions []skillEntry) string {
-	if plan == "" && len(edits) == 0 && len(tools) == 0 && len(skills) == 0 && len(instructions) == 0 {
+func formatPreservedState(plan string, task *preservedTaskState, edits, tools, skills, instructions []skillEntry) string {
+	if plan == "" && task == nil && len(edits) == 0 && len(tools) == 0 && len(skills) == 0 && len(instructions) == 0 {
 		return ""
 	}
-	state := preservedState{Plan: plan}
+	state := preservedState{Plan: plan, Task: task}
 	for _, e := range edits {
 		state.RecentEdits = append(state.RecentEdits, preservedEdit{Path: e.name, Note: e.body})
 	}

internal/agent/compaction_preserve_test.go

@@ -1,6 +1,7 @@
 package agent
 
 import (
+	"encoding/json"
 	"strings"
 	"testing"
 	"unicode/utf8"
@@ -59,6 +60,103 @@ func TestCompactPreservesActivePlan(t *testing.T) {
 	}
 }
 
+func TestCompactPreservesBoundedTaskContext(t *testing.T) {
+	objective := strings.Repeat("世", maxTaskObjectiveBytes)
+	task := newTaskState(objective, nil)
+	task.observe(taskStateEvent{kind: taskStateEventPlan, arguments: `{"plan":[{"content":"write code","status":"in_progress"},{"content":"add tests","status":"pending"}]}`})
+	messages := stateConversation()
+	compacted, err := Compact(messages, CompactionOptions{
+		PreserveLast: 2,
+		Summarize:    func([]zeroruntime.Message) (string, error) { return "SUMMARY", nil },
+		taskState:    task.snapshotForCompaction(messages),
+	})
+	if err != nil {
+		t.Fatalf("Compact: %v", err)
+	}
+	state := parsePreservedStateBlock(compacted[1].Content)
+	if state.Task == nil || state.Task.Status != taskStatusActive || state.Task.InProgress != 1 || state.Task.Pending != 1 {
+		t.Fatalf("unexpected compact task state: %#v", state.Task)
+	}
+	if len(state.Task.Objective) > maxTaskObjectiveBytes || !utf8.ValidString(state.Task.Objective) {
+		t.Fatalf("objective was not safely bounded: %d bytes %q", len(state.Task.Objective), state.Task.Objective)
+	}
+}
+
+func TestCompactPreservesObjectiveAfterPlanParityMismatch(t *testing.T) {
+	prior := preservedState{Task: &preservedTaskState{Objective: "stale objective", Status: taskStatusActive, Pending: 1}}
+	encoded, err := json.Marshal(prior)
+	if err != nil {
+		t.Fatal(err)
+	}
+	messages := []zeroruntime.Message{
+		{Role: zeroruntime.MessageRoleSystem, Content: "system"},
+		{Role: zeroruntime.MessageRoleUser, Content: summaryLabel + "\nold\n\n" + preservedStateLabel + "\n" + string(encoded)},
+		{Role: zeroruntime.MessageRoleAssistant, Content: "continuing"},
+		{Role: zeroruntime.MessageRoleUser, Content: "more"},
+		{Role: zeroruntime.MessageRoleAssistant, Content: "working"},
+		{Role: zeroruntime.MessageRoleUser, Content: "again"},
+		{Role: zeroruntime.MessageRoleAssistant, Content: "done"},
+	}
+	compacted, err := Compact(messages, CompactionOptions{
+		PreserveLast: 2,
+		Summarize:    func([]zeroruntime.Message) (string, error) { return "SUMMARY", nil },
+		taskState: &taskStateSnapshot{
+			Objective:  "current objective",
+			PlanParity: taskPlanParityMismatch,
+		},
+	})
+	if err != nil {
+		t.Fatalf("Compact: %v", err)
+	}
+	state := parsePreservedStateBlock(compacted[1].Content)
+	if state.Task == nil || state.Task.Objective != "current objective" {
+		t.Fatalf("immutable objective was lost on plan mismatch: %#v", state.Task)
+	}
+	if state.Task.Status != "" || state.Task.Pending != 0 {
+		t.Fatalf("uncorroborated mutable task fields survived plan mismatch: %#v", state.Task)
+	}
+}
+
+func TestTaskObjectiveSurvivesRepeatedCompactionWithoutPlanRefresh(t *testing.T) {
+	task := newTaskState("keep this objective", nil)
+	task.observe(taskStateEvent{kind: taskStateEventPlan, arguments: `{"plan":[{"content":"write code","status":"in_progress"},{"content":"add tests","status":"pending"}]}`})
+	messages := stateConversation()
+
+	first, err := Compact(messages, CompactionOptions{
+		PreserveLast: 2,
+		Summarize:    func([]zeroruntime.Message) (string, error) { return "FIRST", nil },
+		taskState:    task.snapshotForCompaction(messages),
+	})
+	if err != nil {
+		t.Fatalf("first Compact: %v", err)
+	}
+	secondInput := append(append([]zeroruntime.Message{}, first...),
+		zeroruntime.Message{Role: zeroruntime.MessageRoleUser, Content: "more"},
+		zeroruntime.Message{Role: zeroruntime.MessageRoleAssistant, Content: "working"},
+		zeroruntime.Message{Role: zeroruntime.MessageRoleUser, Content: "again"},
+		zeroruntime.Message{Role: zeroruntime.MessageRoleAssistant, Content: "done"},
+	)
+	snapshot := task.snapshotForCompaction(secondInput)
+	if snapshot.PlanParity != taskPlanParityMismatch {
+		t.Fatalf("plan call should be absent after first compaction, parity=%q", snapshot.PlanParity)
+	}
+	second, err := Compact(secondInput, CompactionOptions{
+		PreserveLast: 2,
+		Summarize:    func([]zeroruntime.Message) (string, error) { return "SECOND", nil },
+		taskState:    snapshot,
+	})
+	if err != nil {
+		t.Fatalf("second Compact: %v", err)
+	}
+	state := parsePreservedStateBlock(second[1].Content)
+	if state.Task == nil || state.Task.Objective != "keep this objective" {
+		t.Fatalf("objective lost after second compaction: %#v", state.Task)
+	}
+	if state.Task.Status != "" || state.Task.InProgress != 0 {
+		t.Fatalf("uncorroborated mutable fields survived second compaction: %#v", state.Task)
+	}
+}
+
 func TestCompactPreservesLoadedSkills(t *testing.T) {
 	summary := compactStateConversation(t, stateConversation())
 	if !strings.Contains(summary, preservedStateLabel) {
@@ -283,12 +381,10 @@ func TestExtractLatestPlanReturnsMostRecent(t *testing.T) {
 	}
 }
 
-func TestFormatPlanArgumentsAcceptsStepAlias(t *testing.T) {
+func TestFormatPlanArgumentsRejectsUnsupportedStepAlias(t *testing.T) {
 	got := formatPlanArguments(`{"plan":[{"step":"write failing test","status":"in_progress"},{"content":"keep existing shape","status":"pending"}]}`)
-	for _, want := range []string{"- [in_progress] write failing test", "- [pending] keep existing shape"} {
-		if !strings.Contains(got, want) {
-			t.Fatalf("expected %q in formatted plan, got %q", want, got)
-		}
+	if got != "" {
+		t.Fatalf("unsupported alias should reject the whole plan like update_plan, got %q", got)
 	}
 }
 

internal/agent/compaction_test.go

@@ -581,7 +581,7 @@ func TestCompactNeverProducesConsecutiveUserMessages(t *testing.T) {
 }
 
 func TestRecoverNoopDoesNotConsumeReactiveBudget(t *testing.T) {
-	st := newCompactionState(Options{ContextWindow: 1000, CompactionPreserveLast: 2})
+	st := newCompactionState(Options{ContextWindow: 1000, CompactionPreserveLast: 2}, nil)
 	provider := &mockProvider{turns: [][]zeroruntime.StreamEvent{{
 		{Type: zeroruntime.StreamEventText, Content: "SUMMARY"}, {Type: zeroruntime.StreamEventDone},
 	}}}
@@ -628,7 +628,7 @@ func TestRecoverNoopDoesNotConsumeReactiveBudget(t *testing.T) {
 }
 
 func TestRecoverDisabledIsNoop(t *testing.T) {
-	st := newCompactionState(Options{ContextWindow: 0})
+	st := newCompactionState(Options{ContextWindow: 0}, nil)
 	msgs := []zeroruntime.Message{{Role: zeroruntime.MessageRoleUser, Content: "x"}}
 	called := false
 	// recover must not invoke the provider/summarize when disabled, even on a

internal/agent/completion_policy.go

@@ -0,0 +1,86 @@
+package agent
+
+// CompletionDecision is the deterministic outcome of evaluating a text-only
+// assistant turn. Uncertain means the loop needs one bounded follow-up action
+// before it can finalize the run.
+type CompletionDecision string
+
+const (
+	CompletionUncertain  CompletionDecision = "uncertain"
+	CompletionComplete   CompletionDecision = "complete"
+	CompletionIncomplete CompletionDecision = "incomplete"
+)
+
+type completionAction string
+
+const (
+	completionActionNone          completionAction = ""
+	completionActionContinue      completionAction = "continue"
+	completionActionSemanticCheck completionAction = "semantic_check"
+)
+
+type completionEvaluation struct {
+	Decision CompletionDecision
+	Action   completionAction
+	Reason   string
+}
+
+// completionPolicy owns the small amount of state needed to keep uncertain
+// decisions bounded. requireSemanticCheck is set only for run profiles that
+// already opted into self-correction; ordinary completion remains entirely
+// local and adds no model call.
+type completionPolicy struct {
+	continueNudges         int
+	requireSemanticCheck   bool
+	semanticCheckRequested bool
+}
+
+func newCompletionPolicy(requireSemanticCheck bool) *completionPolicy {
+	return &completionPolicy{requireSemanticCheck: requireSemanticCheck}
+}
+
+func (policy *completionPolicy) evaluate(text string, context completionContext) completionEvaluation {
+	// A direct admission is strong local evidence and takes precedence over all
+	// weaker signals, avoiding both continuation nudges and semantic checks.
+	if reason := selfReportedIncompletion(text); reason != "" {
+		return completionEvaluation{Decision: CompletionIncomplete, Reason: reason}
+	}
+
+	// A continuation cue is strong unfinished evidence; a pending plan is only
+	// weak evidence because bookkeeping can be stale. Both get a bounded chance
+	// to continue, but only a persisted cue is ultimately incomplete.
+	cue := endsWithContinuationCue(text)
+	if cue || context.PlanPending {
+		if policy.continueNudges < maxContinueNudges {
+			policy.continueNudges++
+			reason := "your message ended mid-step"
+			if !cue {
+				reason = "pending plan items remain — finish them, or mark them complete with update_plan if you are done"
+			}
+			return completionEvaluation{
+				Decision: CompletionUncertain,
+				Action:   completionActionContinue,
+				Reason:   reason,
+			}
+		}
+		if cue {
+			return completionEvaluation{
+				Decision: CompletionIncomplete,
+				Reason:   "your message ended mid-step",
+			}
+		}
+	}
+
+	// Profiles with self-correction enabled require one task-grounded semantic
+	// check. It is requested at most once per run; the next locally complete turn
+	// is accepted without another model call.
+	if policy.requireSemanticCheck && !policy.semanticCheckRequested {
+		policy.semanticCheckRequested = true
+		return completionEvaluation{
+			Decision: CompletionUncertain,
+			Action:   completionActionSemanticCheck,
+		}
+	}
+
+	return completionEvaluation{Decision: CompletionComplete, Action: completionActionNone}
+}

internal/agent/completion_policy_test.go

@@ -0,0 +1,75 @@
+package agent
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestCompletionPolicyLocalEvidenceDecidesWithoutSemanticCheck(t *testing.T) {
+	policy := newCompletionPolicy(false)
+
+	complete := policy.evaluate("Done. All required checks pass.", completionContext{})
+	if complete.Decision != CompletionComplete {
+		t.Fatalf("confident completion decision = %q, want %q", complete.Decision, CompletionComplete)
+	}
+
+	incomplete := policy.evaluate("I couldn't verify the result, so this is my best guess.", completionContext{})
+	if incomplete.Decision != CompletionIncomplete {
+		t.Fatalf("admitted failure decision = %q, want %q", incomplete.Decision, CompletionIncomplete)
+	}
+}
+
+func TestCompletionPolicyPreservesBoundedPlanStallProtection(t *testing.T) {
+	policy := newCompletionPolicy(false)
+	for attempt := 0; attempt < maxContinueNudges; attempt++ {
+		got := policy.evaluate("Let me inspect the remaining configuration:", completionContext{PlanPending: true})
+		if got.Decision != CompletionUncertain || got.Action != completionActionContinue {
+			t.Fatalf("attempt %d = (%q, %q), want uncertain continue", attempt+1, got.Decision, got.Action)
+		}
+	}
+
+	got := policy.evaluate("Let me inspect the remaining configuration:", completionContext{PlanPending: true})
+	if got.Decision != CompletionIncomplete {
+		t.Fatalf("decision after nudge budget = %q, want %q", got.Decision, CompletionIncomplete)
+	}
+}
+
+func TestCompletionPolicyTreatsPendingPlanAsWeakEvidence(t *testing.T) {
+	policy := newCompletionPolicy(false)
+	for attempt := 0; attempt < maxContinueNudges; attempt++ {
+		got := policy.evaluate("All set.", completionContext{PlanPending: true})
+		if got.Decision != CompletionUncertain || got.Action != completionActionContinue {
+			t.Fatalf("attempt %d = (%q, %q), want uncertain continue", attempt+1, got.Decision, got.Action)
+		}
+	}
+
+	got := policy.evaluate("All set.", completionContext{PlanPending: true})
+	if got.Decision != CompletionComplete {
+		t.Fatalf("stale plan decision after nudge budget = %q, want %q", got.Decision, CompletionComplete)
+	}
+}
+
+func TestCompletionPolicyAllowsExactlyOneRequiredSemanticCheck(t *testing.T) {
+	policy := newCompletionPolicy(true)
+
+	first := policy.evaluate("Implemented and tested.", completionContext{})
+	if first.Decision != CompletionUncertain || first.Action != completionActionSemanticCheck {
+		t.Fatalf("first decision = (%q, %q), want uncertain semantic check", first.Decision, first.Action)
+	}
+
+	second := policy.evaluate("PASS. The result meets the task criterion.", completionContext{})
+	if second.Decision != CompletionComplete {
+		t.Fatalf("post-check decision = %q, want %q", second.Decision, CompletionComplete)
+	}
+	if second.Action == completionActionSemanticCheck {
+		t.Fatal("semantic check was requested more than once")
+	}
+}
+
+func TestAcceptanceVerificationNudgeIncludesBoundedObjective(t *testing.T) {
+	objective := "make the requested behavior observable"
+	nudge := acceptanceVerificationNudge(objective)
+	if !strings.Contains(nudge, "Task objective: "+objective) {
+		t.Fatalf("semantic check was not grounded in the objective: %q", nudge)
+	}
+}

internal/agent/guardrails.go

@@ -1,7 +1,6 @@
 package agent
 
 import (
-	"encoding/json"
 	"strconv"
 	"strings"
 
@@ -127,9 +126,8 @@ func endsWithContinuationCue(text string) bool {
 // which the update_plan tool coerces to "pending") counts as remaining, matching
 // that tool's own status normalization.
 func planStatusRemaining(status string) bool {
-	switch strings.ToLower(strings.TrimSpace(status)) {
-	case "completed", "complete", "done", "finished", "resolved", "✓", "x", "[x]",
-		"failed", "fail", "error", "errored", "blocked", "cancelled", "canceled", "abandoned", "skipped":
+	switch normalizeTaskPlanStatus(status) {
+	case "completed", "failed":
 		return false
 	default:
 		return true
@@ -307,8 +305,8 @@ func hasAnyPrefix(s string, prefixes []string) bool {
 // the bug-hunt surfaced: well-formed output treated as correct; pre-existing tests
 // passing treated as the objective being met; and a result that merely matches a
 // baseline the task asked to beat or improve. General — no task-specific content.
-func acceptanceVerificationNudge() string {
-	return "Before this task can be marked complete, " + acceptanceNudgeMarker + " — " +
+func acceptanceVerificationNudge(objective string) string {
+	nudge := "Before this task can be marked complete, " + acceptanceNudgeMarker + " — " +
 		"NOT the shape or format of your output, NOT that pre-existing tests pass, and NOT that your " +
 		"result merely matches a baseline you were asked to beat or improve. " +
 		"Re-read the original task, then run a concrete check that exercises the actual requirement: " +
@@ -316,6 +314,10 @@ func acceptanceVerificationNudge() string {
 		"thing the task asked you to produce, recover, fix, or optimize. " +
 		"If that check passes, reply PASS and cite the evidence. " +
 		"If it does not pass — or you cannot run such a check — say so plainly and keep working; do not claim success."
+	if objective = capTaskObjective(objective); objective != "" {
+		nudge += "\n\nTask objective: " + objective
+	}
+	return nudge
 }
 
 // toolFailureHintMarker is a stable substring for tests.
@@ -553,16 +555,12 @@ func (state *guardState) pendingPlanItems() bool {
 // many items are still remaining. Malformed arguments leave the prior count
 // unchanged (best-effort — the plan panel itself tolerates the same).
 func (state *guardState) observePlanUpdate(arguments string) {
-	var parsed struct {
-		Plan []struct {
-			Status string `json:"status"`
-		} `json:"plan"`
-	}
-	if json.Unmarshal([]byte(arguments), &parsed) != nil {
+	plan, ok := parseTaskPlan(arguments)
+	if !ok {
 		return
 	}
 	pending := 0
-	for _, item := range parsed.Plan {
+	for _, item := range plan {
 		if planStatusRemaining(item.Status) {
 			pending++
 		}

internal/agent/guardrails_test.go

@@ -169,6 +169,37 @@ func TestRunResetsEmptyTurnCounterOnToolCall(t *testing.T) {
 	}
 }
 
+// The whole point of #702's fix: the unknown-session error's normalized
+// signature must not vary with the session id, so a model probing ids 1, 2,
+// 3, … produces one repeated signature the failure guard can count. If the id
+// leaked into the first 80 normalized chars, each probe would reset the streak
+// and the halt would never fire.
+func TestUnknownExecSessionErrorSignatureIsIDInvariant(t *testing.T) {
+	a := errorSignature(tools.UnknownExecSessionError(1))
+	b := errorSignature(tools.UnknownExecSessionError(999999))
+	if a != b {
+		t.Fatalf("unknown-session signature varies with id:\n  %q\n  %q", a, b)
+	}
+}
+
+// End to end: with an id-invariant signature, probing a different unknown id
+// each turn now trips the repeated-failure halt at toolFailureStopAt, where
+// before the fix it never would.
+func TestUnknownExecSessionProbingTripsFailureHalt(t *testing.T) {
+	var state guardState
+	var stoppedAt int
+	for i := 1; i <= toolFailureStopAt; i++ {
+		out := state.observeToolResult(tools.WriteStdinToolName, true, tools.UnknownExecSessionError(i))
+		if out.Stop {
+			stoppedAt = i
+			break
+		}
+	}
+	if stoppedAt != toolFailureStopAt {
+		t.Fatalf("probing distinct unknown ids stopped at %d, want %d", stoppedAt, toolFailureStopAt)
+	}
+}
+
 func TestGuardStateResetsToolOnlyStreakOnEmptyNonToolTurn(t *testing.T) {
 	var state guardState
 	toolOnly := zeroruntime.CollectedStream{

internal/agent/loop.go

@@ -7,6 +7,7 @@ import (
 	"fmt"
 	"io"
 	"sort"
+	"strconv"
 	"strings"
 	"sync"
 
@@ -15,6 +16,7 @@ import (
 	"github.com/Gitlawb/zero/internal/sandbox"
 	"github.com/Gitlawb/zero/internal/streamjson"
 	"github.com/Gitlawb/zero/internal/tools"
+	"github.com/Gitlawb/zero/internal/trace"
 	"github.com/Gitlawb/zero/internal/zeroruntime"
 )
 
@@ -114,6 +116,53 @@ func Run(ctx context.Context, prompt string, provider Provider, options Options)
 		return Result{}, errors.New("agent provider is required")
 	}
 
+	// Tracing is opt-in. When a recorder is wired, thread it into ctx so the
+	// providerio seam and reconnect helper can reach it via trace.FromContext,
+	// mark the run's start, and wrap OnUsage so token counters accumulate for
+	// free alongside the existing per-request plumbing. nil recorder leaves the
+	// loop byte-identical: FromContext returns nil, the no-op stamps cost
+	// nothing, and the OnUsage wrapper is not installed.
+	if options.Trace != nil {
+		ctx = trace.WithContext(ctx, options.Trace)
+		options.Trace.Start()
+		originalOnUsage := options.OnUsage
+		options.OnUsage = func(usage Usage) {
+			if originalOnUsage != nil {
+				originalOnUsage(usage)
+			}
+			options.Trace.Counter(trace.CounterInputTokens, int64(usage.InputTokens))
+			options.Trace.Counter(trace.CounterCachedInputTokens, int64(usage.CachedInputTokens))
+			options.Trace.Counter(trace.CounterOutputTokens, int64(usage.OutputTokens))
+		}
+	}
+
+	// Establish the run's turn session — the seam an optimized provider session
+	// (connection reuse, prewarm, native compaction) plugs into without touching
+	// this loop. Default: wrap the passed provider so the session's Stream IS
+	// provider.StreamCompletion, byte-identical to calling it directly. Opened
+	// before dispatchSessionStart so a failed open is a clean run-start error
+	// with no session hooks fired and nothing to unwind.
+	turnSessions := options.TurnSessionProvider
+	if turnSessions == nil {
+		turnSessions = zeroruntime.NewProviderTurnSessionProvider(provider, zeroruntime.ProviderCapabilities{})
+	}
+	session, sessionErr := turnSessions.OpenTurnSession(ctx)
+	if sessionErr != nil {
+		return Result{}, fmt.Errorf("agent: open turn session: %w", sessionErr)
+	}
+	// Closed via closure (not `defer session.Close()`) so after a mid-run model
+	// swap the CURRENT session is the one closed at teardown — the swap closes
+	// the old one inline. Close errors are advisory and never fail the run.
+	defer func() { _ = session.Close() }()
+	// Best-effort prewarm: the default adapter no-ops; a real session may prime
+	// a connection. Failure is ignored by contract (never fatal).
+	_ = session.Prewarm(ctx)
+	// Route ALL provider I/O — per-turn streams, mid-stream retries, the
+	// compaction summarizer, and the final-answer request — through the session
+	// by reassigning the loop's provider local. Every existing call site reads
+	// this local, so no signatures change anywhere downstream.
+	provider = sessionProvider{session: session}
+
 	maxTurns := options.MaxTurns
 	if maxTurns <= 0 {
 		maxTurns = 12
@@ -132,10 +181,46 @@ func Run(ctx context.Context, prompt string, provider Provider, options Options)
 	options.runPermissions = runPermissions
 	defer runPermissions.cleanup()
 
-	messages := zeroruntime.SeedMessagesWithImages(buildSystemPrompt(options), prompt, options.Images)
+	promptParts := buildSystemPromptParts(options)
+	messages := zeroruntime.SeedMessagesWithImages(promptParts.prompt, prompt, options.Images)
 
 	guards := newGuardState()
-	compactor := newCompactionState(options)
+	task := newTaskState(prompt, options.Trace)
+	compactor := newCompactionState(options, task)
+	defer func() {
+		// A final transcript comparison is observational. It records drift but
+		// never rewrites the result or changes execution after the fact.
+		task.observePlanParity(result.Messages)
+		// Tool-result observations are intentionally coalesced; this final event
+		// guarantees their aggregate counts are present even on an early return.
+		task.emit()
+	}()
+	// The execution-profile posture controller. nil Options.Profile (every
+	// existing caller) makes every observe/decide call a no-op, keeping the
+	// loop byte-identical for unprofiled runs.
+	posture := newProfileController(options.Profile)
+	// applyPosture applies at most one posture escalation when an armed trigger
+	// has fired: raise the hoisted turn ceiling, restore effort and the
+	// completion gate, stamp the counter. Shared by the end-of-turn tail and
+	// the completion-gate uncertain path (which continues the loop before the
+	// tail runs). No-op forever after the first escalation and for unprofiled
+	// runs.
+	applyPosture := func() {
+		if target, fired := posture.maybeEscalate(); fired {
+			if target.MaxTurns > maxTurns {
+				maxTurns = target.MaxTurns
+			}
+			if target.ReasoningEffort != "" {
+				options.ReasoningEffort = target.ReasoningEffort
+			} else if target.RestoreDefaultEffort {
+				options.ReasoningEffort = ""
+			}
+			if target.RestoreCompletionGate {
+				options.RequireCompletionSignal = true
+			}
+			options.Trace.Counter(trace.CounterPostureEscalations, 1)
+		}
+	}
 
 	// Background post-edit diagnostics: files changed by mutating tools are
 	// checked off the tool-call critical path and any errors are appended as a
@@ -148,13 +233,10 @@ func Run(ctx context.Context, prompt string, provider Provider, options Options)
 	// loaded tool's full schema; it lives only for the run (v1 within-run scope).
 	loaded := map[string]bool{}
 
-	// continueNudges counts how many times the headless completion gate
-	// (Options.RequireCompletionSignal) has re-prompted a no-tool-call turn that
-	// stopped with work still unfinished. Bounded by maxContinueNudges.
-	continueNudges := 0
-	// acceptanceRequested records that the one-time task-grounded acceptance check
-	// has already been demanded this run, so it fires at most once.
-	acceptanceRequested := false
+	// The feature-gated completion policy keeps local completion decisions and its
+	// bounded follow-up state out of the central loop. Self-correcting profiles
+	// opt into the one permitted task-grounded semantic check.
+	completionPolicy := newCompletionPolicy(options.SelfCorrect != nil)
 
 	// toolDefCache memoizes each tool's rendered JSON-schema definition across
 	// turns (a tool's advertised schema is stable for the run), so partitionTools
@@ -164,7 +246,11 @@ func Run(ctx context.Context, prompt string, provider Provider, options Options)
 	result = Result{Messages: copyMessages(messages)}
 	dispatchSessionStart(ctx, options)
 	defer func() {
-		dispatchSessionEnd(ctx, options, result, err)
+		// Use a context detached from ctx's cancellation: on Esc/Ctrl+C the run
+		// context is already canceled by the time this defer runs, and a canceled
+		// parent would make Hooks.Dispatch's context.WithTimeout derive an
+		// already-expired context, so the sessionEnd hook would never actually run.
+		dispatchSessionEnd(context.WithoutCancel(ctx), options, result, err)
 	}()
 	for turn := 0; turn < maxTurns; turn++ {
 		result.Turns = turn + 1
@@ -184,12 +270,38 @@ func Run(ctx context.Context, prompt string, provider Provider, options Options)
 		// the tool-definition tokens (they ride on every request) in its estimate.
 		// partitionTools depends only on registry/permissions/options/loaded, not on
 		// the messages, so computing it before compaction is safe.
+		// Build the per-turn tool list first so proactive compaction can include
+		// the tool-definition tokens (they ride on every request) in its estimate.
+		// partitionTools depends only on registry/permissions/options/loaded, not on
+		// the messages, so computing it before compaction is safe.
+		toolPartitionSpan := options.Trace.Span(trace.SpanToolPartition)
 		exposed, _ := partitionToolsCached(registry, permissionMode, options, loaded, toolDefCache)
+		toolPartitionSpan.End()
+
+		// Fingerprint the exact system prompt built at run start plus this turn's
+		// provider-visible tool definitions in their emitted order. Reusing the
+		// retained prompt parts avoids rebuilding workspace context while ensuring
+		// the trace describes the same bytes carried by the request.
+		if options.Trace != nil {
+			fp := computePrefixFingerprint(buildPromptSubstringsFromParts(promptParts, exposed))
+			options.Trace.EmitPrefixHash(trace.PrefixHash{
+				SystemPromptHash:       fp.SystemPromptHash,
+				BaseInstructionsHash:   fp.BaseInstructionsHash,
+				ConfirmationPolicyHash: fp.ConfirmationPolicyHash,
+				ProjectContextHash:     fp.ProjectContextHash,
+				SkillsHash:             fp.SkillsHash,
+				ToolsHash:              fp.ToolsHash,
+				SchemaHash:             fp.SchemaHash,
+				CompletePrefixHash:     fp.CompletePrefixHash,
+			})
+		}
 
 		// PROACTIVE compaction: if the history is approaching the model's
 		// context window, summarize the oldest middle before building the
 		// request. A no-op when ContextWindow == 0 (compaction disabled).
+		compactionSpan := options.Trace.Span(trace.SpanCompaction)
 		messages = compactor.maybeCompact(ctx, provider, messages, exposed)
+		compactionSpan.End()
 		request := zeroruntime.CompletionRequest{
 			Messages:        copyMessages(messages),
 			Tools:           exposed,
@@ -255,11 +367,39 @@ func Run(ctx context.Context, prompt string, provider Provider, options Options)
 		// conversation-state duplication.
 		forwardedVisibleText := false
 		forwardingOpts := zeroruntime.CollectOptions{OnUsage: options.OnUsage}
-		if options.OnText != nil {
-			forwardingOpts.OnText = func(s string) { forwardedVisibleText = true; options.OnText(s) }
+		// Install text/reasoning forwarding handlers whenever EITHER a user
+		// callback OR a trace recorder is set. A headless traced run (e.g. `zero
+		// exec --trace`) sets Trace but no OnText/OnReasoning; without these
+		// handlers the stream is still collected, but FirstTokenAt would never
+		// stamp and the trace would lose its TTFT signal. The trace recorder's
+		// stamp methods are nil-safe, but we guard on `trace != nil` so a run with
+		// a user callback but no recorder still works. forwardedVisibleText stays
+		// tied to the USER callback only, preserving the stall-retry semantics
+		// (a trace-only handler forwards nothing the user would see duplicated).
+		rec := options.Trace
+		onText := options.OnText
+		if onText != nil || rec != nil {
+			forwardingOpts.OnText = func(s string) {
+				if rec != nil {
+					rec.StampFirstVisibleEvent()
+					rec.StampFirstToken()
+				}
+				if onText != nil {
+					forwardedVisibleText = true
+					onText(s)
+				}
+			}
 		}
-		if options.OnReasoning != nil {
-			forwardingOpts.OnReasoning = func(s string) { options.OnReasoning(s) }
+		onReasoning := options.OnReasoning
+		if onReasoning != nil || rec != nil {
+			forwardingOpts.OnReasoning = func(s string) {
+				if rec != nil {
+					rec.StampFirstToken()
+				}
+				if onReasoning != nil {
+					onReasoning(s)
+				}
+			}
 		}
 		if options.OnToolCallStart != nil {
 			forwardingOpts.OnToolCallStart = func(id, name string) { options.OnToolCallStart(id, name) }
@@ -297,14 +437,18 @@ func Run(ctx context.Context, prompt string, provider Provider, options Options)
 				if retryStreamErr != nil {
 					return collected, retryStreamErr
 				}
+				genSpan := options.Trace.Span(trace.SpanGeneration)
 				collected = zeroruntime.CollectStreamWithOptions(ctx, retryStream, zeroruntime.CollectOptions{
 					OnUsage: options.OnUsage,
 				})
+				genSpan.End()
 			}
 			return collected, nil
 		}
 
+		generationSpan := options.Trace.Span(trace.SpanGeneration)
 		collected := zeroruntime.CollectStreamWithOptions(ctx, stream, forwardingOpts)
+		generationSpan.End()
 		if collected.Error != "" {
 			updated, stop := recoverStreamError(collected)
 			collected = updated
@@ -357,7 +501,9 @@ func Run(ctx context.Context, prompt string, provider Provider, options Options)
 				result.Messages = copyMessages(messages)
 				return result, retryErr
 			}
+			stallGenSpan := options.Trace.Span(trace.SpanGeneration)
 			collected = zeroruntime.CollectStreamWithOptions(ctx, retryStream, forwardingOpts)
+			stallGenSpan.End()
 		}
 		if collected.Error != "" {
 			// Route a reissued stream's non-stall error through the SAME recovery as
@@ -433,67 +579,42 @@ func Run(ctx context.Context, prompt string, provider Provider, options Options)
 			// model's final answer ONLY when the work is actually done. Default off
 			// (RequireCompletionSignal), so interactive runs stay byte-identical.
 			if options.RequireCompletionSignal {
-				// (1) Self-report downgrade (strongest, unambiguous): the model's own
-				// final message admits it guessed / could not meet the objective. Checked
-				// FIRST so an admitted-impossible task is downgraded immediately (no wasted
-				// continue-nudges) and reports the accurate reason.
-				if reason := selfReportedIncompletion(collected.Text); reason != "" {
+				completionContext := task.completionContext(messages, guards.pendingPlanItems())
+				evaluation := completionPolicy.evaluate(collected.Text, completionContext)
+				task.observe(taskStateEvent{kind: taskStateEventCompletion, completion: evaluation})
+				switch evaluation.Decision {
+				case CompletionIncomplete:
 					result.Incomplete = true
-					result.IncompleteReason = reason
+					result.IncompleteReason = evaluation.Reason
 					result.FinalAnswer = collected.Text
 					result.Messages = copyMessages(messages)
 					return result, nil
-				}
-
-				// (2) The model stopped without a tool call while work may be unfinished:
-				//   - a continuation cue ("…Let me check the config:") is an unambiguous
-				//     mid-step stop;
-				//   - pending update_plan items are a WEAK, ambiguous signal (the model may
-				//     have finished without re-marking the last step).
-				// Nudge to continue (bounded). After the budget: a persisted continuation
-				// cue finalizes INCOMPLETE; pending-plan WITHOUT a cue does NOT (that would
-				// false-fail a completed run with stale bookkeeping) — fall through to the
-				// acceptance check / success.
-				cue := endsWithContinuationCue(collected.Text)
-				planPending := guards.pendingPlanItems()
-				if cue || planPending {
-					if continueNudges < maxContinueNudges {
-						continueNudges++
-						reason := "your message ended mid-step"
-						if !cue {
-							reason = "pending plan items remain — finish them, or mark them complete with update_plan if you are done"
-						}
+				case CompletionUncertain:
+					// Observe the uncertainty signal and apply any escalation NOW:
+					// this branch continues the turn loop before the end-of-turn
+					// act point, so deferring would skip escalation entirely.
+					posture.observeUncertain()
+					applyPosture()
+					switch evaluation.Action {
+					case completionActionContinue:
+						options.Trace.Counter(trace.CounterCompletionNudges, 1)
 						messages = append(messages, zeroruntime.Message{
 							Role:    zeroruntime.MessageRoleUser,
-							Content: continueNudge(reason),
+							Content: continueNudge(evaluation.Reason),
+						})
+					case completionActionSemanticCheck:
+						options.Trace.Counter(trace.CounterAcceptanceChecks, 1)
+						messages = append(messages, zeroruntime.Message{
+							Role:    zeroruntime.MessageRoleUser,
+							Content: acceptanceVerificationNudge(completionContext.Objective),
 						})
-						continue
 					}
-					if cue {
-						result.Incomplete = true
-						result.IncompleteReason = "your message ended mid-step"
-						result.FinalAnswer = collected.Text
-						result.Messages = copyMessages(messages)
-						return result, nil
-					}
-					// pending-plan only, budget spent: trust the model's completion claim
-					// over stale plan bookkeeping; fall through.
-				}
-
-				// (3) Task-grounded acceptance: before accepting a "done" turn as success,
-				// require ONE acceptance check grounded in the task's stated criterion
-				// (only when self-correct is on). Rejects "well-formed == correct",
-				// "existing-tests-pass == objective met", and "result == baseline" false
-				// successes. Bounded to a single pass; a genuine post-check completion
-				// (no admission, no cue) then finalizes as success on the next turn.
-				if options.SelfCorrect != nil && !acceptanceRequested {
-					acceptanceRequested = true
-					messages = append(messages, zeroruntime.Message{
-						Role:    zeroruntime.MessageRoleUser,
-						Content: acceptanceVerificationNudge(),
-					})
 					continue
+				case CompletionComplete:
+					// Local evidence is sufficient; proceed to final diagnostics.
 				}
+			} else {
+				task.observe(taskStateEvent{kind: taskStateEventCompletion, completion: completionEvaluation{Decision: CompletionComplete}})
 			}
 			// Finalization diagnostics gate: edits from this run may still have
 			// checks in flight — the per-turn drain waits only briefly and defers
@@ -517,6 +638,11 @@ func Run(ctx context.Context, prompt string, provider Provider, options Options)
 		// executing so the empty-turn counter resets and plan-tracking signals
 		// stay current.
 		guards.observeTurn(collected)
+		for _, call := range collected.ToolCalls {
+			if call.Name == planToolName {
+				task.observe(taskStateEvent{kind: taskStateEventPlan, arguments: call.Arguments})
+			}
+		}
 
 		failureHint := ""
 		// turnRequestedModel records the FIRST mid-run escalation target requested
@@ -543,25 +669,32 @@ func Run(ctx context.Context, prompt string, provider Provider, options Options)
 			// The scan happens lazily at the run's first index — never ahead of a
 			// pending mutating call — so read-after-write ordering is preserved.
 			if index >= precomputedEnd {
-				runEnd := index
-				for runEnd < len(collected.ToolCalls) && parallelSafeToolCall(registry, collected.ToolCalls[runEnd], options) {
-					runEnd++
-				}
+				// Capability-safe consecutive run (ReadOnly+ThreadSafe, no
+				// resource-key conflicts). See extendParallelRun.
+				runEnd := extendParallelRun(registry, collected.ToolCalls, index, options)
 				if runEnd-index >= 2 {
+					batchSpan := options.Trace.Span(trace.SpanToolExecution)
 					precomputed = executeParallelReadBatch(ctx, registry, collected.ToolCalls, index, runEnd, permissionMode, options)
+					batchSpan.End()
 					precomputedStart, precomputedEnd = index, runEnd
 				}
 			}
 			if options.OnToolCall != nil {
 				options.OnToolCall(call)
 			}
+			options.Trace.StampFirstUsefulAction()
 			var toolResult ToolResult
 			var abortErr error
 			if index >= precomputedStart && index < precomputedEnd {
 				toolResult, abortErr = precomputed[index-precomputedStart].result, precomputed[index-precomputedStart].abortErr
 			} else {
+				toolSpan := options.Trace.Span(trace.SpanToolExecution)
 				toolResult, abortErr = executeToolCall(ctx, registry, call, permissionMode, options)
+				toolSpan.End()
 			}
+			options.Trace.Counter(trace.CounterToolCalls, 1)
+			recordOutputBudgetTrace(options.Trace, toolResult)
+			task.observe(taskStateEvent{kind: taskStateEventToolResult, toolResult: toolResult})
 			if options.OnToolResult != nil {
 				options.OnToolResult(toolResult)
 			}
@@ -608,6 +741,7 @@ func Run(ctx context.Context, prompt string, provider Provider, options Options)
 			// would misdirect the model toward JSON shape or blocked behavior.
 			retriableFailure := isRetriableToolError(toolResult)
 			outcome := guards.observeToolResult(call.Name, retriableFailure, toolResult.Output)
+			posture.observeToolOutcome(outcome, toolResult)
 			if outcome.Stop {
 				// The assistant message advertised EVERY collected tool call, but
 				// the guard halts mid-turn so the calls after this one never run.
@@ -640,7 +774,10 @@ func Run(ctx context.Context, prompt string, provider Provider, options Options)
 		// the assistant's tool_results stay contiguous (a user message between
 		// tool_results breaks strict provider replay). nil SelfCorrect is a no-op.
 		if options.SelfCorrect != nil && len(changedFilesThisBatch) > 0 {
-			if feedback, _ := options.SelfCorrect.AfterEdit(ctx, dedupeStrings(changedFilesThisBatch)); feedback != "" {
+			feedback, selfCorrectOutcome := options.SelfCorrect.AfterEdit(ctx, dedupeStrings(changedFilesThisBatch))
+			posture.observeSelfCorrect(selfCorrectOutcome)
+			task.observe(taskStateEvent{kind: taskStateEventVerification, verification: selfCorrectOutcome})
+			if feedback != "" {
 				messages = append(messages, zeroruntime.Message{
 					Role:    zeroruntime.MessageRoleUser,
 					Content: feedback,
@@ -653,24 +790,53 @@ func Run(ctx context.Context, prompt string, provider Provider, options Options)
 		// of the run. At most one switch per turn (first request wins). A switcher
 		// error is NON-FATAL — record a brief note and continue on the current
 		// model. nil switcher ⇒ requests are ignored entirely (escalation off).
-		if turnRequestedModel != "" && options.ModelSwitcher != nil {
-			newProvider, switchErr := options.ModelSwitcher(ctx, turnRequestedModel)
+		if turnRequestedModel != "" && (options.ModelSessionSwitcher != nil || options.ModelSwitcher != nil) {
+			// Resolve the escalated model's session source. The target-aware
+			// ModelSessionSwitcher is preferred: its TurnSessionProvider carries an
+			// optimized session (and capabilities) across the swap. The legacy
+			// ModelSwitcher fallback returns a bare Provider, wrapped in the
+			// default no-op session — identical to pre-seam behavior.
+			var newSessions zeroruntime.TurnSessionProvider
+			var switchErr error
+			if options.ModelSessionSwitcher != nil {
+				newSessions, switchErr = options.ModelSessionSwitcher(ctx, turnRequestedModel)
+			} else {
+				var newProvider Provider
+				newProvider, switchErr = options.ModelSwitcher(ctx, turnRequestedModel)
+				if switchErr == nil && newProvider != nil {
+					newSessions = zeroruntime.NewProviderTurnSessionProvider(newProvider, zeroruntime.ProviderCapabilities{})
+				}
+			}
 			if switchErr != nil {
 				messages = append(messages, zeroruntime.Message{
 					Role:    zeroruntime.MessageRoleUser,
 					Content: escalationFailedNoticePrefix + " (" + turnRequestedModel + "): " + switchErr.Error() + ". Continuing on " + options.Model + ".",
 				})
-			} else if newProvider != nil {
-				// Reassign the local provider so the next turn's StreamCompletion and
-				// compaction use it; update options.Model so subsequent RunOptions.Model,
-				// context-window sizing, and usage attribution follow the new model.
-				provider = newProvider
-				options.Model = turnRequestedModel
-				// KNOWN LIMITATION (deferred): the compactor's context-window budget
-				// is fixed at run start from options.ContextWindow and is NOT updated
-				// here, so a switch to a model with a different window keeps compacting
-				// against the original budget. Fixing it needs a ModelSwitcher contract
-				// change (return the new window) — out of scope for this change.
+			} else if newSessions != nil {
+				// Open the new session and close the old one, so the next turn's
+				// streams and compaction use the new model. For the default adapter
+				// the open never errors and Close is a no-op, so this stays
+				// byte-identical to a direct provider reassignment; the guarded open
+				// and prewarm matter once a session holds real state.
+				newSession, openErr := newSessions.OpenTurnSession(ctx)
+				if openErr != nil {
+					messages = append(messages, zeroruntime.Message{
+						Role:    zeroruntime.MessageRoleUser,
+						Content: escalationFailedNoticePrefix + " (" + turnRequestedModel + "): " + openErr.Error() + ". Continuing on " + options.Model + ".",
+					})
+				} else {
+					_ = session.Close()
+					session = newSession
+					_ = session.Prewarm(ctx)
+					provider = sessionProvider{session: session}
+					options.Model = turnRequestedModel
+					options.Trace.Counter(trace.CounterModelSwitches, 1)
+					// KNOWN LIMITATION (deferred): the compactor's context-window budget
+					// is fixed at run start from options.ContextWindow and is NOT updated
+					// here, so a switch to a model with a different window keeps compacting
+					// against the original budget. Fixing it needs the switcher to also
+					// report the new window — out of scope for this change.
+				}
 			}
 		}
 
@@ -704,6 +870,13 @@ func Run(ctx context.Context, prompt string, provider Provider, options Options)
 				Content: reminder,
 			})
 		}
+
+		// One-shot posture escalation: when an armed profile trigger fired this
+		// turn, restore the stricter knob values the profile displaced. Mutates
+		// only per-turn-read policy (the hoisted turn ceiling, reasoning effort,
+		// completion gate); never messages, model, or session. No-op forever
+		// after the first escalation and for every unprofiled run.
+		applyPosture()
 	}
 
 	if ctx.Err() != nil {
@@ -746,6 +919,28 @@ func Run(ctx context.Context, prompt string, provider Provider, options Options)
 	return result, nil
 }
 
+func recordOutputBudgetTrace(recorder *trace.Recorder, result ToolResult) {
+	if recorder == nil || result.Meta["output_budget_category"] == "" {
+		return
+	}
+	parseInt := func(key string) int {
+		value, _ := strconv.Atoi(result.Meta[key])
+		return value
+	}
+	spillCreated, _ := strconv.ParseBool(result.Meta["output_budget_spill_created"])
+	recorder.EmitOutputBudget(trace.OutputBudgetEvent{
+		Tool:                    result.Name,
+		Category:                result.Meta["output_budget_category"],
+		OriginalBytes:           parseInt("output_budget_original_bytes"),
+		RetainedBytes:           parseInt("output_budget_retained_bytes"),
+		EstimatedOriginalTokens: parseInt("output_budget_estimated_original_tokens"),
+		EstimatedRetainedTokens: parseInt("output_budget_estimated_retained_tokens"),
+		Truncated:               result.Truncated,
+		Reason:                  result.Meta["output_budget_reason"],
+		SpillCreated:            spillCreated,
+	})
+}
+
 func finalAnswerAfterMaxTurns(ctx context.Context, provider Provider, messages []zeroruntime.Message, toolDefs []zeroruntime.ToolDefinition, options Options) (string, []zeroruntime.Message, string) {
 	finalMessages := copyMessages(messages)
 	finalMessages = append(finalMessages, zeroruntime.Message{
@@ -764,6 +959,7 @@ func finalAnswerAfterMaxTurns(ctx context.Context, provider Provider, messages [
 	if err != nil {
 		return "", messages, ""
 	}
+	finalGenSpan := options.Trace.Span(trace.SpanGeneration)
 	collected := zeroruntime.CollectStreamWithOptions(ctx, stream, zeroruntime.CollectOptions{
 		OnText:          options.OnText,
 		OnReasoning:     options.OnReasoning,
@@ -771,6 +967,7 @@ func finalAnswerAfterMaxTurns(ctx context.Context, provider Provider, messages [
 		OnToolCallStart: options.OnToolCallStart,
 		OnToolCallDelta: options.OnToolCallDelta,
 	})
+	finalGenSpan.End()
 	if ctx.Err() != nil || collected.Error != "" || strings.TrimSpace(collected.Text) == "" {
 		return "", messages, ""
 	}
@@ -1198,16 +1395,33 @@ func executeToolCall(ctx context.Context, registry *tools.Registry, call ToolCal
 			if didRedact {
 				result.Redacted = true
 			}
+			result = registry.RebudgetAfterHook(call.Name, args, result)
 		}
 	}
+	// Stamp the sandbox risk classification for this EXECUTED call so run-policy
+	// observers can see the risk of an allowed mutation. Prefer the preflight
+	// decision's classification when the sandbox evaluated the call; otherwise
+	// run the same pure classifier the permission path uses. Denied/canceled
+	// results returned earlier keep the zero value.
+	executedRisk := sandbox.Risk{}
+	if preflightDecision != nil {
+		executedRisk = preflightDecision.Risk
+	} else if toolFound {
+		// Unknown-tool results fall through here with a nil tool; they carry a
+		// denial and keep the zero risk value.
+		executedRisk = sandbox.Classify(sandboxRequest(call.Name, tool, args, permissionGranted, permissionMode, options))
+	}
+
 	// Secret scrubbing happens at the registry boundary (the single point both
 	// the agent loop and the MCP server pass through), so result.Output is
 	// already redacted here and result.Redacted reflects whether it changed.
 	return ToolResult{
+		Risk:         executedRisk,
 		ToolCallID:   call.ID,
 		Name:         call.Name,
 		Status:       result.Status,
 		Output:       result.Output,
+		Truncated:    result.Truncated,
 		Meta:         result.Meta,
 		Redacted:     result.Redacted,
 		ChangedFiles: result.ChangedFiles,
@@ -1518,6 +1732,7 @@ func toolResultFromPrePermissionReject(call ToolCall, result tools.Result) ToolR
 		Name:           call.Name,
 		Status:         result.Status,
 		Output:         output,
+		Truncated:      result.Truncated,
 		Meta:           meta,
 		Redacted:       result.Redacted || outputRedacted || summaryRedacted || metaRedacted,
 		ChangedFiles:   result.ChangedFiles,
@@ -1787,6 +2002,7 @@ func askUserFallbackResult(ctx context.Context, registry *tools.Registry, call T
 			Name:         call.Name,
 			Status:       result.Status,
 			Output:       result.Output,
+			Truncated:    result.Truncated,
 			Meta:         result.Meta,
 			Redacted:     result.Redacted,
 			ChangedFiles: result.ChangedFiles,
@@ -1874,7 +2090,10 @@ func requestPermission(ctx context.Context, request PermissionRequest, options O
 	if options.OnPermissionRequest == nil {
 		return PermissionDecision{Action: PermissionDecisionDeny, Reason: request.Reason}, nil
 	}
-	return options.OnPermissionRequest(ctx, request)
+	permSpan := options.Trace.Span(trace.SpanPermissionWait)
+	decision, err := options.OnPermissionRequest(ctx, request)
+	permSpan.End()
+	return decision, err
 }
 
 func normalizePermissionDecisionAction(action PermissionDecisionAction) PermissionDecisionAction {

internal/agent/loop_test.go

@@ -6,7 +6,9 @@ import (
 	"errors"
 	"fmt"
 	"os"
+	"os/exec"
 	"path/filepath"
+	"reflect"
 	"runtime"
 	"strings"
 	"testing"
@@ -15,6 +17,7 @@ import (
 	"github.com/Gitlawb/zero/internal/sandbox"
 	"github.com/Gitlawb/zero/internal/specmode"
 	"github.com/Gitlawb/zero/internal/tools"
+	"github.com/Gitlawb/zero/internal/trace"
 	"github.com/Gitlawb/zero/internal/zeroruntime"
 )
 
@@ -92,6 +95,87 @@ func TestRunDispatchesSessionLifecycleHooks(t *testing.T) {
 	}
 }
 
+// cancelingProvider simulates an Esc/Ctrl+C abort: it cancels the run's own
+// context mid-stream (as the TUI's interrupt handler would) and returns no
+// events, so Run observes ctx.Err() and returns early with an already-canceled
+// context in scope for the deferred sessionEnd dispatch.
+type cancelingProvider struct {
+	cancel context.CancelFunc
+}
+
+func (provider *cancelingProvider) StreamCompletion(ctx context.Context, request zeroruntime.CompletionRequest) (<-chan zeroruntime.StreamEvent, error) {
+	provider.cancel()
+	ch := make(chan zeroruntime.StreamEvent)
+	close(ch)
+	return ch, nil
+}
+
+// TestRunDispatchesSessionEndHookAfterContextCancellation is a regression test
+// for a bug where an interrupted run (Esc/Ctrl+C) canceled ctx before the
+// deferred sessionEnd dispatch ran, so Hooks.Dispatch's context.WithTimeout(ctx, ...)
+// derived an already-canceled context and the hook command never actually launched.
+func TestRunDispatchesSessionEndHookAfterContextCancellation(t *testing.T) {
+	goBinary, err := exec.LookPath("go")
+	if err != nil {
+		// The test binary runs on the build machine, so its build-time GOROOT
+		// still identifies the toolchain that produced it.
+		goRoot := runtime.GOROOT() //nolint:staticcheck // Safe for this non-portable test binary.
+		goBinary = filepath.Join(goRoot, "bin", "go")
+		if runtime.GOOS == "windows" {
+			goBinary += ".exe"
+		}
+		if _, statErr := os.Stat(goBinary); statErr != nil {
+			t.Skipf("go binary unavailable on PATH or in GOROOT: %v", statErr)
+		}
+	}
+	audit, err := hooks.NewAuditStore(hooks.AuditStoreOptions{AuditPath: filepath.Join(t.TempDir(), "audit.jsonl")})
+	if err != nil {
+		t.Fatalf("NewAuditStore: %v", err)
+	}
+	dispatcher := hooks.NewDispatcher(hooks.DispatcherOptions{
+		Config: hooks.Config{
+			Enabled: true,
+			Hooks: []hooks.Definition{
+				{ID: "zero.session-end", Event: hooks.EventSessionEnd, Command: goBinary, Args: []string{"version"}, Enabled: true},
+			},
+		},
+		Audit: audit,
+	})
+
+	ctx, cancel := context.WithCancel(context.Background())
+	provider := &cancelingProvider{cancel: cancel}
+
+	_, err = Run(ctx, "hi", provider, Options{
+		SessionID:    "session-cancel",
+		Cwd:          t.TempDir(),
+		ProviderName: "test-provider",
+		Model:        "test-model",
+		Hooks:        dispatcher,
+	})
+	if !errors.Is(err, context.Canceled) {
+		t.Fatalf("Run err = %v, want context.Canceled", err)
+	}
+
+	events, err := audit.ReadEvents()
+	if err != nil {
+		t.Fatalf("ReadEvents: %v", err)
+	}
+	var completedStatus hooks.AuditStatus
+	found := false
+	for _, event := range events {
+		if event.Type == "hook_execution_completed" && event.Event == hooks.EventSessionEnd {
+			completedStatus = event.Status
+			found = true
+		}
+	}
+	if !found {
+		t.Fatalf("no sessionEnd hook_execution_completed audit event, events=%#v", events)
+	}
+	if completedStatus != hooks.AuditCompleted {
+		t.Fatalf("sessionEnd hook status = %q, want %q (hook must actually run despite ctx cancellation)", completedStatus, hooks.AuditCompleted)
+	}
+}
+
 type recordingWebSearchTool struct {
 	calls []map[string]any
 }
@@ -1175,6 +1259,46 @@ func TestRunExecutesToolCallThroughRegistry(t *testing.T) {
 	}
 }
 
+func TestRunPreservesRequestPrefixAcrossTurns(t *testing.T) {
+	root := t.TempDir()
+	writeAgentTestFile(t, filepath.Join(root, "notes.txt"), "alpha\n")
+	registry := tools.NewRegistry()
+	registry.Register(tools.NewReadFileTool(root))
+	provider := &mockProvider{turns: [][]zeroruntime.StreamEvent{
+		{
+			{Type: zeroruntime.StreamEventToolCallStart, ToolCallID: "call-1", ToolName: "read_file"},
+			{Type: zeroruntime.StreamEventToolCallDelta, ToolCallID: "call-1", ArgumentsFragment: `{"path":"notes.txt"}`},
+			{Type: zeroruntime.StreamEventToolCallEnd, ToolCallID: "call-1"},
+			{Type: zeroruntime.StreamEventDone},
+		},
+		{
+			{Type: zeroruntime.StreamEventText, Content: "done"},
+			{Type: zeroruntime.StreamEventDone},
+		},
+	}}
+
+	if _, err := Run(context.Background(), "read notes", provider, Options{
+		Cwd:       root,
+		Registry:  registry,
+		SessionID: "session-stable-prefix",
+	}); err != nil {
+		t.Fatal(err)
+	}
+	if len(provider.requests) != 2 {
+		t.Fatalf("provider requests = %d, want 2", len(provider.requests))
+	}
+	first, second := provider.requests[0], provider.requests[1]
+	if len(second.Messages) < len(first.Messages) || !reflect.DeepEqual(second.Messages[:len(first.Messages)], first.Messages) {
+		t.Fatalf("first request messages must be an exact prefix of the second:\nfirst=%#v\nsecond=%#v", first.Messages, second.Messages)
+	}
+	if !reflect.DeepEqual(first.Tools, second.Tools) {
+		t.Fatalf("tool definitions drifted between turns:\nfirst=%#v\nsecond=%#v", first.Tools, second.Tools)
+	}
+	if first.PromptCacheKey != "session-stable-prefix" || second.PromptCacheKey != first.PromptCacheKey {
+		t.Fatalf("prompt cache key must remain stable: first=%q second=%q", first.PromptCacheKey, second.PromptCacheKey)
+	}
+}
+
 func TestRunSanitizesMalformedToolCallArgumentsBeforeRetry(t *testing.T) {
 	root := t.TempDir()
 	registry := tools.NewRegistry()
@@ -3461,3 +3585,73 @@ func TestRunDoesNotFlagCleanToolOutput(t *testing.T) {
 		t.Errorf("clean output should not get a reminder, got %q", captured.Output)
 	}
 }
+
+// TestRunTracingWrapperStampsUsage verifies the per-turn tracing setup in Run:
+// a wired recorder is Started, OnUsage is wrapped so it still forwards to the
+// caller's callback AND stamps token counters, and the run completes.
+func TestRunTracingWrapperStampsUsage(t *testing.T) {
+	provider := &mockProvider{turns: [][]zeroruntime.StreamEvent{{
+		{Type: zeroruntime.StreamEventUsage, Usage: zeroruntime.Usage{InputTokens: 100, CachedInputTokens: 20, OutputTokens: 40}},
+		{Type: zeroruntime.StreamEventText, Content: "done"},
+		{Type: zeroruntime.StreamEventDone},
+	}}}
+	onUsageCalls := 0
+	rec := trace.NewRecorder("tracing-session", "run-1", "test")
+	if _, err := Run(context.Background(), "hi", provider, Options{
+		SessionID:    "tracing-session",
+		Cwd:          t.TempDir(),
+		ProviderName: "test-provider",
+		Model:        "test-model",
+		Trace:        rec,
+		OnUsage:      func(Usage) { onUsageCalls++ },
+	}); err != nil {
+		t.Fatalf("Run: %v", err)
+	}
+	tr := rec.Finish()
+	if tr.StartedAt.IsZero() {
+		t.Fatal("tracing wrapper did not Start the recorder")
+	}
+	// FirstTokenAt must stamp even though no OnText/OnReasoning user callback is
+	// set: a headless traced run (e.g. `zero exec --trace`) sets Trace but no UI
+	// callbacks, so the loop installs trace-only forwarding handlers to capture
+	// TTFT. Without them FirstTokenAt stays zero and the trace loses its signal.
+	if tr.FirstTokenAt.IsZero() {
+		t.Fatal("FirstTokenAt not stamped for a traced run with no OnText/OnReasoning callbacks")
+	}
+	if got := tr.Counter(trace.CounterInputTokens); got != 100 {
+		t.Fatalf("input token counter = %d, want 100", got)
+	}
+	if got := tr.Counter(trace.CounterCachedInputTokens); got != 20 {
+		t.Fatalf("cached input token counter = %d, want 20", got)
+	}
+	if got := tr.Counter(trace.CounterOutputTokens); got != 40 {
+		t.Fatalf("output token counter = %d, want 40", got)
+	}
+	if onUsageCalls == 0 {
+		t.Fatal("wrapped OnUsage did not forward to the caller's callback")
+	}
+}
+
+// TestRunNilTraceForwardsUsage verifies a nil recorder leaves the loop
+// byte-identical: OnUsage is not wrapped, so the caller's callback still fires
+// and nothing panics.
+func TestRunNilTraceForwardsUsage(t *testing.T) {
+	provider := &mockProvider{turns: [][]zeroruntime.StreamEvent{{
+		{Type: zeroruntime.StreamEventUsage, Usage: zeroruntime.Usage{InputTokens: 7}},
+		{Type: zeroruntime.StreamEventText, Content: "done"},
+		{Type: zeroruntime.StreamEventDone},
+	}}}
+	onUsageCalls := 0
+	if _, err := Run(context.Background(), "hi", provider, Options{
+		SessionID:    "nil-trace-session",
+		Cwd:          t.TempDir(),
+		ProviderName: "test-provider",
+		Model:        "test-model",
+		OnUsage:      func(Usage) { onUsageCalls++ },
+	}); err != nil {
+		t.Fatalf("Run: %v", err)
+	}
+	if onUsageCalls == 0 {
+		t.Fatal("OnUsage not forwarded when Trace is nil")
+	}
+}

internal/agent/output_budget_propagation_test.go

@@ -0,0 +1,167 @@
+package agent
+
+import (
+	"context"
+	"os"
+	"strconv"
+	"strings"
+	"testing"
+
+	"github.com/Gitlawb/zero/internal/hooks"
+	"github.com/Gitlawb/zero/internal/tools"
+	"github.com/Gitlawb/zero/internal/trace"
+	"github.com/Gitlawb/zero/internal/zeroruntime"
+)
+
+type propagationOutputTool struct {
+	output string
+}
+
+func TestOutputBudgetHookHelperProcess(t *testing.T) {
+	for index, arg := range os.Args {
+		if arg != "--zero-output-budget-hook" || index+1 >= len(os.Args) {
+			continue
+		}
+		if _, err := os.Stdout.WriteString(os.Args[index+1]); err != nil {
+			os.Exit(2)
+		}
+		os.Exit(0)
+	}
+}
+
+func largeOutputBudgetHookDispatcher() *hooks.Dispatcher {
+	feedback := strings.Repeat("hook feedback ", 200)
+	return hooks.NewDispatcher(hooks.DispatcherOptions{Config: hooks.Config{
+		Enabled: true,
+		Hooks: []hooks.Definition{{
+			ID:      "large-feedback",
+			Event:   hooks.EventAfterTool,
+			Matcher: "propagation_output",
+			Command: os.Args[0],
+			Args: []string{
+				"-test.run=TestOutputBudgetHookHelperProcess",
+				"--",
+				"--zero-output-budget-hook",
+				feedback,
+			},
+			Enabled: true,
+		}},
+	}})
+}
+
+func (tool propagationOutputTool) Name() string        { return "propagation_output" }
+func (tool propagationOutputTool) Description() string { return "returns output for propagation tests" }
+func (tool propagationOutputTool) Parameters() tools.Schema {
+	return tools.Schema{Type: "object", AdditionalProperties: false}
+}
+func (tool propagationOutputTool) Safety() tools.Safety {
+	return tools.Safety{SideEffect: tools.SideEffectRead, Permission: tools.PermissionAllow, Reason: "test read"}
+}
+func (tool propagationOutputTool) Run(context.Context, map[string]any) tools.Result {
+	return tools.Result{Status: tools.StatusOK, Output: tool.output}
+}
+
+func TestExecuteToolCallPropagatesOutputTruncation(t *testing.T) {
+	t.Setenv("TMPDIR", t.TempDir())
+	t.Setenv("ZERO_TOOL_OUTPUT_CEILING_TOKENS", "80")
+	registry := tools.NewRegistry()
+	registry.Register(propagationOutputTool{output: strings.Repeat("large output\n", 1000)})
+
+	result, abortErr := executeToolCall(context.Background(), registry, ToolCall{
+		ID:        "call-budget",
+		Name:      "propagation_output",
+		Arguments: `{}`,
+	}, PermissionModeAuto, Options{Cwd: t.TempDir()})
+	if abortErr != nil {
+		t.Fatalf("executeToolCall abort error: %v", abortErr)
+	}
+	if !result.Truncated {
+		t.Fatalf("agent ToolResult lost tools.Result.Truncated: %#v", result)
+	}
+	if result.Meta["spill_path"] == "" {
+		t.Fatalf("agent ToolResult lost spill metadata: %#v", result.Meta)
+	}
+}
+
+func TestRecordOutputBudgetTraceUsesOnlyCompactMetadata(t *testing.T) {
+	recorder := trace.NewRecorder("session", "run", "")
+	recorder.Start()
+	recordOutputBudgetTrace(recorder, ToolResult{
+		Name:      "grep",
+		Truncated: true,
+		Output:    "SECRET OUTPUT MUST NOT ENTER TRACE",
+		Meta: map[string]string{
+			"output_budget_category":                  "search",
+			"output_budget_original_bytes":            "1000",
+			"output_budget_retained_bytes":            "100",
+			"output_budget_estimated_original_tokens": "250",
+			"output_budget_estimated_retained_tokens": "25",
+			"output_budget_reason":                    "semantic_search_budget",
+			"output_budget_spill_created":             "true",
+			"spill_path":                              "/secret/path/not-for-trace",
+		},
+	})
+	events := recorder.Finish().OutputBudgets
+	if len(events) != 1 {
+		t.Fatalf("events = %#v", events)
+	}
+	event := events[0]
+	if event.Tool != "grep" || event.Category != "search" || event.OriginalBytes != 1000 || event.RetainedBytes != 100 || !event.SpillCreated {
+		t.Fatalf("unexpected trace event: %#v", event)
+	}
+}
+
+func TestExecuteToolCallRebudgetsOversizedAfterToolFeedback(t *testing.T) {
+	t.Setenv("ZERO_TOOL_OUTPUT_CEILING_TOKENS", "80")
+	registry := tools.NewRegistry()
+	registry.Register(propagationOutputTool{output: "tool output"})
+	dispatcher := largeOutputBudgetHookDispatcher()
+
+	result, abortErr := executeToolCall(context.Background(), registry, ToolCall{
+		ID:        "call-hook-budget",
+		Name:      "propagation_output",
+		Arguments: `{}`,
+	}, PermissionModeAuto, Options{Hooks: dispatcher})
+	if abortErr != nil {
+		t.Fatalf("executeToolCall abort error: %v", abortErr)
+	}
+	if !result.Truncated || len(result.Output) > 80*4 {
+		t.Fatalf("afterTool feedback bypassed output budget: truncated=%t bytes=%d meta=%#v", result.Truncated, len(result.Output), result.Meta)
+	}
+	if result.Meta["output_budget_category"] == "" || result.Meta["output_budget_retained_bytes"] != strconv.Itoa(len(result.Output)) {
+		t.Fatalf("post-hook budget metadata does not describe final output: %#v", result.Meta)
+	}
+}
+
+func TestRunTraceReflectsPostHookBudget(t *testing.T) {
+	t.Setenv("ZERO_TOOL_OUTPUT_CEILING_TOKENS", "80")
+	registry := tools.NewRegistry()
+	registry.Register(propagationOutputTool{output: "tool output"})
+	dispatcher := largeOutputBudgetHookDispatcher()
+	provider := &mockProvider{turns: [][]zeroruntime.StreamEvent{
+		{
+			{Type: zeroruntime.StreamEventToolCallStart, ToolCallID: "call-hook-trace", ToolName: "propagation_output"},
+			{Type: zeroruntime.StreamEventToolCallDelta, ToolCallID: "call-hook-trace", ArgumentsFragment: `{}`},
+			{Type: zeroruntime.StreamEventToolCallEnd, ToolCallID: "call-hook-trace"},
+			{Type: zeroruntime.StreamEventDone},
+		},
+		{{Type: zeroruntime.StreamEventText, Content: "done"}, {Type: zeroruntime.StreamEventDone}},
+	}}
+	recorder := trace.NewRecorder("session", "run", "")
+	var toolResults []ToolResult
+	if _, err := Run(context.Background(), "budget hook", provider, Options{
+		Registry:     registry,
+		Hooks:        dispatcher,
+		Trace:        recorder,
+		OnToolResult: func(result ToolResult) { toolResults = append(toolResults, result) },
+	}); err != nil {
+		t.Fatalf("Run: %v", err)
+	}
+	if len(toolResults) != 1 || !toolResults[0].Truncated {
+		t.Fatalf("tool result = %#v, want one truncated post-hook result", toolResults)
+	}
+	events := recorder.Finish().OutputBudgets
+	if len(events) != 1 || !events[0].Truncated || events[0].RetainedBytes != len(toolResults[0].Output) {
+		t.Fatalf("trace does not describe final post-hook output: events=%#v result=%#v", events, toolResults[0])
+	}
+}

internal/agent/parallel_tools.go

@@ -10,12 +10,23 @@ import (
 // Parallel read-ahead for tool batches. When a turn requests several
 // independent lookups (read_file + grep + glob is the common shape), executing
 // them one after another serializes pure I/O waits. A consecutive run of
-// auto-allowed read-only calls is executed concurrently instead; results are
+// capability-safe read-only calls is executed concurrently instead; results are
 // then consumed in the original call order, so guard counters, message
 // ordering, abort semantics, and the surface's call/result event pairing are
 // byte-identical to sequential execution. Runs never span a mutating call: a
 // read that follows a write must observe the write, so eligibility is decided
 // per consecutive run, not per batch.
+//
+// Eligibility uses the PR5 tool-effect contract (tools.CapabilitiesOf):
+//
+//	Effect == ReadOnly
+//	AND ThreadSafe == true
+//	AND auto-allowed (no interactive permission prompt on the hot path)
+//	AND no resource-key conflict with an earlier call in the same concurrent window
+//
+// Unknown, mutators, interactive tools, and non-thread-safe reads stay
+// sequential. Empty resource keys do not conflict (ThreadSafe is the safety
+// gate); shared non-empty keys force a batch boundary.
 
 // maxParallelReadTools bounds concurrent read-only tool executions in a turn.
 const maxParallelReadTools = 8
@@ -28,28 +39,117 @@ type precomputedToolResult struct {
 }
 
 // parallelSafeToolCall reports whether call may run concurrently with its
-// neighbors: the tool must exist, be side-effect-free (SideEffectRead), and be
-// auto-allowed for these args, so no interactive prompt or workspace mutation
-// is on the hot path. Loop-intercepted tools (ask_user, request_permissions)
-// and tool_search (mutates the deferred-tool set) stay sequential.
+// neighbors under the PR5 capability contract. Loop-intercepted tools
+// (ask_user, request_permissions) and tool_search (mutates the deferred-tool
+// set) always stay sequential.
 func parallelSafeToolCall(registry *tools.Registry, call ToolCall, options Options) bool {
 	switch call.Name {
 	case "ask_user", tools.RequestPermissionsToolName, tools.ToolSearchToolName:
 		return false
 	}
 	tool, found := registry.Get(call.Name)
-	if !found || tool.Safety().SideEffect != tools.SideEffectRead {
+	if !found {
 		return false
 	}
-	args := map[string]any{}
-	if call.Arguments != "" {
-		if err := decodeToolArguments(call.Arguments, &args); err != nil {
-			return false
-		}
+	caps := tools.CapabilitiesOf(tool)
+	// Fail-closed: only audited concurrent-safe pure reads.
+	if caps.Effect != tools.EffectReadOnly || !caps.ThreadSafe {
+		return false
+	}
+	args, ok := decodeCallArgs(call)
+	if !ok {
+		return false
 	}
 	return effectivePermission(tool, args) == tools.PermissionAllow
 }
 
+// decodeCallArgs decodes tool call JSON arguments. Returns false on malformed
+// input so the call stays sequential (never panics into the parallel path).
+func decodeCallArgs(call ToolCall) (map[string]any, bool) {
+	args := map[string]any{}
+	if call.Arguments == "" {
+		return args, true
+	}
+	if err := decodeToolArguments(call.Arguments, &args); err != nil {
+		return nil, false
+	}
+	return args, true
+}
+
+// resourceKeysForCall returns the conflict keys for a call, or nil when the
+// tool has no ResourceKeys function / no keys for these args.
+func resourceKeysForCall(registry *tools.Registry, call ToolCall) []string {
+	tool, found := registry.Get(call.Name)
+	if !found {
+		return nil
+	}
+	caps := tools.CapabilitiesOf(tool)
+	if caps.ResourceKeys == nil {
+		return nil
+	}
+	args, ok := decodeCallArgs(call)
+	if !ok {
+		return nil
+	}
+	return caps.ResourceKeys(args)
+}
+
+// resourceKeysConflict reports whether two key sets share any non-empty key.
+// Empty key sets never conflict: ThreadSafe is the eligibility gate; keys only
+// refine conflict detection among tools that declare specific resources.
+func resourceKeysConflict(a, b []string) bool {
+	if len(a) == 0 || len(b) == 0 {
+		return false
+	}
+	seen := make(map[string]struct{}, len(a))
+	for _, key := range a {
+		if key == "" {
+			continue
+		}
+		seen[key] = struct{}{}
+	}
+	for _, key := range b {
+		if key == "" {
+			continue
+		}
+		if _, ok := seen[key]; ok {
+			return true
+		}
+	}
+	return false
+}
+
+// extendParallelRun returns the exclusive end index of a consecutive parallel-
+// safe run starting at start. The run stops before the first call that is not
+// parallel-safe or that conflicts on resource keys with any earlier call in
+// the same window (so two read_file calls on the same path stay sequential).
+func extendParallelRun(registry *tools.Registry, calls []ToolCall, start int, options Options) int {
+	if start >= len(calls) || !parallelSafeToolCall(registry, calls[start], options) {
+		return start
+	}
+	end := start + 1
+	keysWindow := [][]string{resourceKeysForCall(registry, calls[start])}
+	for end < len(calls) {
+		if !parallelSafeToolCall(registry, calls[end], options) {
+			break
+		}
+		nextKeys := resourceKeysForCall(registry, calls[end])
+		conflict := false
+		for _, prev := range keysWindow {
+			if resourceKeysConflict(prev, nextKeys) {
+				conflict = true
+				break
+			}
+		}
+		if conflict {
+			break
+		}
+		keysWindow = append(keysWindow, nextKeys)
+		end++
+	}
+	return end
+}
+
 // executeParallelReadBatch runs calls[start:end] concurrently (bounded by
 // maxParallelReadTools) and returns results indexed relative to start. All
 // execution-side callbacks that can fire inside executeToolCall are serialized

internal/agent/parallel_tools_test.go

@@ -57,6 +57,20 @@ func (tool *probeTool) Parameters() tools.Schema {
 func (tool *probeTool) Safety() tools.Safety {
 	return tools.Safety{SideEffect: tool.sideEffect, Permission: tools.PermissionAllow, Reason: "test"}
 }
+
+// Capabilities maps the probe's SideEffect into the PR5 capability contract so
+// parallelSafeToolCall (CapabilitiesOf) can classify reads vs mutators. Without
+// this, probes default to EffectUnknown and never enter the concurrent path.
+func (tool *probeTool) Capabilities() tools.ToolCapabilities {
+	switch tool.sideEffect {
+	case tools.SideEffectRead:
+		return tools.ToolCapabilities{Effect: tools.EffectReadOnly, ThreadSafe: true}
+	case tools.SideEffectWrite:
+		return tools.ToolCapabilities{Effect: tools.EffectWorkspaceWrite, ThreadSafe: false}
+	default:
+		return tools.UnknownCapabilities()
+	}
+}
 func (tool *probeTool) Run(_ context.Context, args map[string]any) tools.Result {
 	id, _ := args["id"].(string)
 	tool.mu.Lock()
@@ -92,6 +106,11 @@ func TestParallelSafeToolCall(t *testing.T) {
 	registry := tools.NewRegistry()
 	registry.Register(&probeTool{name: "probe_read", sideEffect: tools.SideEffectRead})
 	registry.Register(&probeTool{name: "probe_write", sideEffect: tools.SideEffectWrite})
+	// Read-only but not ThreadSafe: must stay sequential under the PR5 gate.
+	registry.Register(&keyedProbeTool{
+		probeTool:  probeTool{name: "probe_read_serial", sideEffect: tools.SideEffectRead},
+		threadSafe: false,
+	})
 
 	call := func(name, args string) ToolCall { return ToolCall{ID: "c", Name: name, Arguments: args} }
 	if !parallelSafeToolCall(registry, call("probe_read", `{"id":"a"}`), Options{}) {
@@ -109,6 +128,91 @@ func TestParallelSafeToolCall(t *testing.T) {
 	if parallelSafeToolCall(registry, call("ask_user", `{}`), Options{}) {
 		t.Fatal("loop-intercepted tools must stay sequential")
 	}
+	if parallelSafeToolCall(registry, call("probe_read_serial", `{"id":"a"}`), Options{}) {
+		t.Fatal("ReadOnly without ThreadSafe must not be parallel-safe")
+	}
+}
+
+func TestResourceKeysConflict(t *testing.T) {
+	if resourceKeysConflict(nil, []string{"file:a"}) {
+		t.Fatal("empty vs non-empty must not conflict")
+	}
+	if resourceKeysConflict([]string{"file:a"}, nil) {
+		t.Fatal("non-empty vs empty must not conflict")
+	}
+	if resourceKeysConflict([]string{"file:a"}, []string{"file:b"}) {
+		t.Fatal("distinct keys must not conflict")
+	}
+	if !resourceKeysConflict([]string{"file:a", "file:b"}, []string{"file:b"}) {
+		t.Fatal("shared key must conflict")
+	}
+	if resourceKeysConflict([]string{"", "file:a"}, []string{""}) {
+		t.Fatal("empty-string keys must be ignored")
+	}
+}
+
+func TestExtendParallelRunResourceKeyBoundary(t *testing.T) {
+	// Two keyed reads on the same path must not share a concurrent window;
+	// distinct paths may batch together.
+	registry := tools.NewRegistry()
+	registry.Register(&keyedProbeTool{
+		probeTool:  probeTool{name: "keyed_read", sideEffect: tools.SideEffectRead},
+		threadSafe: true,
+		keys: func(args map[string]any) []string {
+			id, _ := args["id"].(string)
+			if id == "" {
+				return nil
+			}
+			return []string{"file:" + id}
+		},
+	})
+	calls := []ToolCall{
+		{ID: "1", Name: "keyed_read", Arguments: `{"id":"a"}`},
+		{ID: "2", Name: "keyed_read", Arguments: `{"id":"b"}`},
+		{ID: "3", Name: "keyed_read", Arguments: `{"id":"a"}`}, // conflicts with call 0
+	}
+	// start=0: a and b share no key → run covers [0,2)
+	if end := extendParallelRun(registry, calls, 0, Options{}); end != 2 {
+		t.Fatalf("extend from 0 = %d, want 2 (stop before second file:a)", end)
+	}
+	// start=2: single remaining call
+	if end := extendParallelRun(registry, calls, 2, Options{}); end != 3 {
+		t.Fatalf("extend from 2 = %d, want 3", end)
+	}
+	// Empty keys never conflict: three keyless safe reads form one window.
+	registry.Register(&probeTool{name: "keyless_read", sideEffect: tools.SideEffectRead})
+	keyless := []ToolCall{
+		{ID: "1", Name: "keyless_read", Arguments: `{"id":"x"}`},
+		{ID: "2", Name: "keyless_read", Arguments: `{"id":"y"}`},
+		{ID: "3", Name: "keyless_read", Arguments: `{"id":"z"}`},
+	}
+	if end := extendParallelRun(registry, keyless, 0, Options{}); end != 3 {
+		t.Fatalf("keyless extend = %d, want 3", end)
+	}
+}
+
+// keyedProbeTool is a probe with explicit ResourceKeys / ThreadSafe for
+// planner unit tests.
+type keyedProbeTool struct {
+	probeTool
+	threadSafe bool
+	keys       func(args map[string]any) []string
+}
+
+func (tool *keyedProbeTool) Capabilities() tools.ToolCapabilities {
+	caps := tools.ToolCapabilities{
+		Effect:     tools.EffectReadOnly,
+		ThreadSafe: tool.threadSafe,
+	}
+	if tool.keys != nil {
+		caps.ResourceKeys = tool.keys
+	}
+	// Honor mutator side effects from the embedded probe when used as write.
+	if tool.sideEffect == tools.SideEffectWrite {
+		caps.Effect = tools.EffectWorkspaceWrite
+		caps.ThreadSafe = false
+	}
+	return caps
 }
 
 func TestRunExecutesConsecutiveReadsConcurrently(t *testing.T) {

internal/agent/profile_controller.go

@@ -0,0 +1,118 @@
+package agent
+
+import (
+	"github.com/Gitlawb/zero/internal/sandbox"
+)
+
+// profileController observes per-turn run signals and decides at most one
+// posture escalation per run for the armed execution profile. A nil policy (or
+// a policy without Escalate) makes every method a no-op, so runs without a
+// profile are byte-identical to before — the same opt-in convention as Trace
+// and SelfCorrect.
+//
+// The controller only ever CHANGES loop policy knobs (turn ceiling, reasoning
+// effort, completion gate) through the values the loop applies at its act
+// point; it never injects messages, never touches the model or session, and
+// never interacts with the model-initiated escalate_model path.
+type profileController struct {
+	policy *PostureEscalation
+
+	escalated     bool
+	uncertainSeen int
+
+	failureTripped bool
+	riskTripped    bool
+	scTripped      bool
+	uncertainTrip  bool
+}
+
+// newProfileController is nil-safe: a nil ProfilePolicy (the default for every
+// existing caller) or a nil Escalate yields a controller that observes and
+// decides nothing.
+func newProfileController(policy *ProfilePolicy) *profileController {
+	if policy == nil {
+		return &profileController{}
+	}
+	return &profileController{policy: policy.Escalate}
+}
+
+// observeToolOutcome watches two signals from an executed tool call: the
+// repeated-failure guard's streak (reusing the guard's own counting, not a
+// second failure model) and the sandbox risk classification of an executed
+// result.
+func (c *profileController) observeToolOutcome(outcome toolFailureOutcome, result ToolResult) {
+	if c.policy == nil || c.escalated {
+		return
+	}
+	if c.policy.OnToolFailureStreak > 0 && outcome.Count >= c.policy.OnToolFailureStreak {
+		c.failureTripped = true
+	}
+	if threshold := riskRank(c.policy.OnRiskyMutation); threshold > 0 &&
+		result.DenialReason == DenialNone &&
+		riskRank(result.Risk.Level) >= threshold {
+		// The call EXECUTED (was not denied): partial failures count too, since
+		// the mutation ran. An unrecognized threshold ranks 0 and disables the
+		// signal instead of matching everything.
+		c.riskTripped = true
+	}
+}
+
+// observeUncertain counts uncertain completion evaluations (continue nudges and
+// semantic checks). Headless-only by construction: the completion gate never
+// runs interactively.
+func (c *profileController) observeUncertain() {
+	if c.policy == nil || c.escalated || c.policy.OnCompletionUncertain <= 0 {
+		return
+	}
+	c.uncertainSeen++
+	if c.uncertainSeen >= c.policy.OnCompletionUncertain {
+		c.uncertainTrip = true
+	}
+}
+
+// observeSelfCorrect watches the post-edit verification outcome. Any failing
+// outcome (correcting, reported, aborted) is a signal; passed and disabled are
+// not.
+func (c *profileController) observeSelfCorrect(outcome Outcome) {
+	if c.policy == nil || c.escalated || !c.policy.OnSelfCorrectFailure {
+		return
+	}
+	switch outcome {
+	case OutcomeCorrecting, OutcomeReported, OutcomeAborted:
+		c.scTripped = true
+	}
+}
+
+// maybeEscalate reports the escalation target exactly once, the first time any
+// armed trigger has fired. Subsequent calls return false for the rest of the
+// run: escalation is one-shot and never de-escalates, so no cooldown state is
+// needed.
+func (c *profileController) maybeEscalate() (PostureEscalation, bool) {
+	if c.policy == nil || c.escalated {
+		return PostureEscalation{}, false
+	}
+	if !(c.failureTripped || c.riskTripped || c.scTripped || c.uncertainTrip) {
+		return PostureEscalation{}, false
+	}
+	c.escalated = true
+	return *c.policy, true
+}
+
+// riskRank orders sandbox risk levels for threshold comparison. Unknown levels
+// rank 0: an unrecognized RESULT level can never meet a valid threshold, and an
+// unrecognized THRESHOLD is rejected before comparison (rank 0 disables the
+// signal) so a typo in a profile can never make every result match.
+func riskRank(level sandbox.RiskLevel) int {
+	switch level {
+	case sandbox.RiskLow:
+		return 1
+	case sandbox.RiskMedium:
+		return 2
+	case sandbox.RiskHigh:
+		return 3
+	case sandbox.RiskCritical:
+		return 4
+	default:
+		return 0
+	}
+}

internal/agent/profile_controller_test.go

@@ -0,0 +1,345 @@
+package agent
+
+import (
+	"context"
+	"strings"
+	"testing"
+
+	"github.com/Gitlawb/zero/internal/sandbox"
+	"github.com/Gitlawb/zero/internal/tools"
+	"github.com/Gitlawb/zero/internal/trace"
+	"github.com/Gitlawb/zero/internal/zeroruntime"
+)
+
+func TestProfileControllerNilPolicyIsNoOp(t *testing.T) {
+	for _, controller := range []*profileController{
+		newProfileController(nil),
+		newProfileController(&ProfilePolicy{Name: "balanced"}), // Escalate nil
+	} {
+		controller.observeToolOutcome(toolFailureOutcome{Count: 99}, ToolResult{Status: tools.StatusOK, Risk: sandbox.Risk{Level: sandbox.RiskCritical}})
+		controller.observeUncertain()
+		controller.observeSelfCorrect(OutcomeAborted)
+		if _, fired := controller.maybeEscalate(); fired {
+			t.Fatal("nil policy must never escalate")
+		}
+	}
+}
+
+func TestProfileControllerEscalatesOnFailureStreak(t *testing.T) {
+	controller := newProfileController(&ProfilePolicy{Escalate: &PostureEscalation{OnToolFailureStreak: 2, MaxTurns: 80}})
+	controller.observeToolOutcome(toolFailureOutcome{Count: 1}, ToolResult{Status: tools.StatusError})
+	if _, fired := controller.maybeEscalate(); fired {
+		t.Fatal("streak below threshold must not escalate")
+	}
+	controller.observeToolOutcome(toolFailureOutcome{Count: 2}, ToolResult{Status: tools.StatusError})
+	target, fired := controller.maybeEscalate()
+	if !fired || target.MaxTurns != 80 {
+		t.Fatalf("expected escalation with the policy target, got fired=%t target=%+v", fired, target)
+	}
+}
+
+func TestProfileControllerEscalatesOnRiskyMutation(t *testing.T) {
+	controller := newProfileController(&ProfilePolicy{Escalate: &PostureEscalation{OnRiskyMutation: sandbox.RiskHigh}})
+	// Medium risk on an executed result: below threshold.
+	controller.observeToolOutcome(toolFailureOutcome{}, ToolResult{Status: tools.StatusOK, Risk: sandbox.Risk{Level: sandbox.RiskMedium}})
+	if _, fired := controller.maybeEscalate(); fired {
+		t.Fatal("medium risk must not trip a high threshold")
+	}
+	// Critical risk on a DENIED result: never counts (the mutation never ran).
+	controller.observeToolOutcome(toolFailureOutcome{}, ToolResult{Status: tools.StatusError, DenialReason: DenialSandboxBlock, Risk: sandbox.Risk{Level: sandbox.RiskCritical}})
+	if _, fired := controller.maybeEscalate(); fired {
+		t.Fatal("a denied result must not trip the risky-mutation signal")
+	}
+	// Critical risk on an executed PARTIAL FAILURE (error status, no denial):
+	// the mutation ran, so it counts.
+	controller.observeToolOutcome(toolFailureOutcome{}, ToolResult{Status: tools.StatusError, Risk: sandbox.Risk{Level: sandbox.RiskCritical}})
+	if _, fired := controller.maybeEscalate(); !fired {
+		t.Fatal("an executed partial failure at critical risk must trip a high threshold")
+	}
+}
+
+func TestProfileControllerIgnoresInvalidRiskThreshold(t *testing.T) {
+	controller := newProfileController(&ProfilePolicy{Escalate: &PostureEscalation{OnRiskyMutation: sandbox.RiskLevel("hgih")}})
+	controller.observeToolOutcome(toolFailureOutcome{}, ToolResult{Status: tools.StatusOK, Risk: sandbox.Risk{Level: sandbox.RiskCritical}})
+	if _, fired := controller.maybeEscalate(); fired {
+		t.Fatal("an unrecognized threshold must disable the signal, not match every result")
+	}
+}
+
+func TestProfileControllerEscalatesOnSelfCorrectFailure(t *testing.T) {
+	controller := newProfileController(&ProfilePolicy{Escalate: &PostureEscalation{OnSelfCorrectFailure: true}})
+	controller.observeSelfCorrect(OutcomePassed)
+	controller.observeSelfCorrect(OutcomeDisabled)
+	if _, fired := controller.maybeEscalate(); fired {
+		t.Fatal("passing/disabled outcomes must not escalate")
+	}
+	controller.observeSelfCorrect(OutcomeReported)
+	if _, fired := controller.maybeEscalate(); !fired {
+		t.Fatal("a failing verification outcome must escalate")
+	}
+}
+
+func TestProfileControllerEscalatesOnUncertainCompletion(t *testing.T) {
+	controller := newProfileController(&ProfilePolicy{Escalate: &PostureEscalation{OnCompletionUncertain: 2}})
+	controller.observeUncertain()
+	if _, fired := controller.maybeEscalate(); fired {
+		t.Fatal("first uncertain evaluation must not trip a threshold of 2")
+	}
+	controller.observeUncertain()
+	if _, fired := controller.maybeEscalate(); !fired {
+		t.Fatal("second uncertain evaluation must escalate")
+	}
+}
+
+func TestProfileControllerEscalatesAtMostOnce(t *testing.T) {
+	controller := newProfileController(&ProfilePolicy{Escalate: &PostureEscalation{OnToolFailureStreak: 1}})
+	controller.observeToolOutcome(toolFailureOutcome{Count: 1}, ToolResult{Status: tools.StatusError})
+	if _, fired := controller.maybeEscalate(); !fired {
+		t.Fatal("expected first escalation")
+	}
+	controller.observeToolOutcome(toolFailureOutcome{Count: 5}, ToolResult{Status: tools.StatusOK, Risk: sandbox.Risk{Level: sandbox.RiskCritical}})
+	controller.observeUncertain()
+	if _, fired := controller.maybeEscalate(); fired {
+		t.Fatal("escalation must be one-shot per run")
+	}
+}
+
+// TestPostureEscalationOnUncertainCompletion proves the uncertain-path act
+// point: the completion gate's continue branch escapes the end-of-turn tail,
+// so escalation must apply before the continue. A cue turn under the gate
+// counts as uncertain, escalates, and the very next request carries the target
+// effort.
+func TestPostureEscalationOnUncertainCompletion(t *testing.T) {
+	provider := &mockProvider{turns: [][]zeroruntime.StreamEvent{
+		{
+			{Type: zeroruntime.StreamEventText, Content: "Let me read the file:"},
+			{Type: zeroruntime.StreamEventDone},
+		},
+		{
+			{Type: zeroruntime.StreamEventText, Content: "Done. All set."},
+			{Type: zeroruntime.StreamEventDone},
+		},
+	}}
+
+	recorder := trace.NewRecorder("posture-session", "run-2", "fast")
+	result, err := Run(context.Background(), "go", provider, Options{
+		Registry:                tools.NewRegistry(),
+		MaxTurns:                10,
+		RequireCompletionSignal: true,
+		Trace:                   recorder,
+		Profile: &ProfilePolicy{
+			Name: "fast",
+			Escalate: &PostureEscalation{
+				ReasoningEffort:       "high",
+				OnCompletionUncertain: 1,
+			},
+		},
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if result.FinalAnswer != "Done. All set." {
+		t.Fatalf("expected the completed answer, got %q", result.FinalAnswer)
+	}
+	if len(provider.requests) != 2 {
+		t.Fatalf("expected 2 requests, got %d", len(provider.requests))
+	}
+	if provider.requests[1].ReasoningEffort != "high" {
+		t.Fatalf("expected the post-escalation request to carry the target effort, got %q", provider.requests[1].ReasoningEffort)
+	}
+	tr := recorder.Finish()
+	if got := tr.Counter(trace.CounterPostureEscalations); got != 1 {
+		t.Fatalf("posture_escalations = %d, want 1", got)
+	}
+}
+
+// A profile that filled the run's effort displaced the provider default ("");
+// RestoreDefaultEffort lets escalation restore that default, which a plain ""
+// ReasoningEffort target cannot express (it means "leave untouched").
+func TestPostureEscalationRestoresDefaultEffort(t *testing.T) {
+	provider := &mockProvider{turns: [][]zeroruntime.StreamEvent{
+		{
+			{Type: zeroruntime.StreamEventText, Content: "Let me read the file:"},
+			{Type: zeroruntime.StreamEventDone},
+		},
+		{
+			{Type: zeroruntime.StreamEventText, Content: "Done. All set."},
+			{Type: zeroruntime.StreamEventDone},
+		},
+	}}
+
+	result, err := Run(context.Background(), "go", provider, Options{
+		Registry:                tools.NewRegistry(),
+		MaxTurns:                10,
+		ReasoningEffort:         "low",
+		RequireCompletionSignal: true,
+		Profile: &ProfilePolicy{
+			Name: "fast",
+			Escalate: &PostureEscalation{
+				RestoreDefaultEffort:  true,
+				OnCompletionUncertain: 1,
+			},
+		},
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if result.FinalAnswer != "Done. All set." {
+		t.Fatalf("expected the completed answer, got %q", result.FinalAnswer)
+	}
+	if len(provider.requests) != 2 {
+		t.Fatalf("expected 2 requests, got %d", len(provider.requests))
+	}
+	if provider.requests[0].ReasoningEffort != "low" {
+		t.Fatalf("pre-escalation request effort = %q, want the profile's low", provider.requests[0].ReasoningEffort)
+	}
+	if provider.requests[1].ReasoningEffort != "" {
+		t.Fatalf("post-escalation request effort = %q, want the restored provider default (empty)", provider.requests[1].ReasoningEffort)
+	}
+}
+
+// failingProfileTool always errors with the same signature so the repeated-
+// failure guard builds a streak.
+type failingProfileTool struct{}
+
+func (failingProfileTool) Name() string        { return "flaky_probe" }
+func (failingProfileTool) Description() string { return "always fails identically (test)" }
+func (failingProfileTool) Parameters() tools.Schema {
+	return tools.Schema{Type: "object", AdditionalProperties: false}
+}
+func (failingProfileTool) Safety() tools.Safety {
+	return tools.Safety{SideEffect: tools.SideEffectRead, Permission: tools.PermissionAllow}
+}
+func (failingProfileTool) Run(context.Context, map[string]any) tools.Result {
+	return tools.Result{Status: tools.StatusError, Output: "probe exploded: same signature"}
+}
+
+// TestPostureEscalationRaisesTurnCeilingMidRun proves the end-to-end act path:
+// a Fast-style run with a 2-turn ceiling hits a failure streak, escalates, and
+// finishes on a turn the original ceiling would have cut off, with the effort
+// target applied to the post-escalation request and the counter emitted.
+func TestPostureEscalationRaisesTurnCeilingMidRun(t *testing.T) {
+	registry := tools.NewRegistry()
+	registry.Register(failingProfileTool{})
+
+	toolTurn := []zeroruntime.StreamEvent{
+		{Type: zeroruntime.StreamEventToolCallStart, ToolCallID: "c1", ToolName: "flaky_probe"},
+		{Type: zeroruntime.StreamEventToolCallEnd, ToolCallID: "c1"},
+		{Type: zeroruntime.StreamEventDone},
+	}
+	provider := &mockProvider{turns: [][]zeroruntime.StreamEvent{
+		toolTurn,
+		toolTurn,
+		{
+			{Type: zeroruntime.StreamEventText, Content: "recovered after escalation"},
+			{Type: zeroruntime.StreamEventDone},
+		},
+	}}
+
+	recorder := trace.NewRecorder("posture-session", "run-1", "fast")
+	result, err := Run(context.Background(), "go", provider, Options{
+		Registry: registry,
+		MaxTurns: 2,
+		Trace:    recorder,
+		Profile: &ProfilePolicy{
+			Name: "fast",
+			Escalate: &PostureEscalation{
+				MaxTurns:            4,
+				ReasoningEffort:     "high",
+				OnToolFailureStreak: 2,
+			},
+		},
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if result.FinalAnswer != "recovered after escalation" {
+		t.Fatalf("expected the run to continue past the original 2-turn ceiling, got %q (turns=%d)", result.FinalAnswer, result.Turns)
+	}
+	if len(provider.requests) != 3 {
+		t.Fatalf("expected 3 requests (ceiling raised from 2 to 4), got %d", len(provider.requests))
+	}
+	if provider.requests[2].ReasoningEffort != "high" {
+		t.Fatalf("expected the post-escalation request to carry the target effort, got %q", provider.requests[2].ReasoningEffort)
+	}
+	tr := recorder.Finish()
+	if got := tr.Counter(trace.CounterPostureEscalations); got != 1 {
+		t.Fatalf("posture_escalations = %d, want 1", got)
+	}
+}
+
+// TestPostureEscalationAbsentWithoutProfile pins the no-regression invariant at
+// the loop level: the identical failing script without a profile ends at the
+// original ceiling with the max-turns answer.
+func TestPostureEscalationAbsentWithoutProfile(t *testing.T) {
+	registry := tools.NewRegistry()
+	registry.Register(failingProfileTool{})
+
+	toolTurn := []zeroruntime.StreamEvent{
+		{Type: zeroruntime.StreamEventToolCallStart, ToolCallID: "c1", ToolName: "flaky_probe"},
+		{Type: zeroruntime.StreamEventToolCallEnd, ToolCallID: "c1"},
+		{Type: zeroruntime.StreamEventDone},
+	}
+	provider := &mockProvider{turns: [][]zeroruntime.StreamEvent{toolTurn, toolTurn}}
+
+	result, err := Run(context.Background(), "go", provider, Options{
+		Registry: registry,
+		MaxTurns: 2,
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(provider.requests) > 3 {
+		t.Fatalf("unprofiled run must not extend the ceiling, got %d requests", len(provider.requests))
+	}
+	if !strings.Contains(result.FinalAnswer, "maximum number of turns") {
+		t.Fatalf("unprofiled run must end with the max-turns answer, got %q", result.FinalAnswer)
+	}
+}
+
+// TestExecuteToolCallClassifiesRiskWithoutSandbox verifies the executed-risk
+// stamp on the unsandboxed path: a read-only tool classifies low.
+func TestExecuteToolCallClassifiesRiskWithoutSandbox(t *testing.T) {
+	registry := tools.NewRegistry()
+	registry.Register(failingProfileTool{})
+
+	result, abortErr := executeToolCall(
+		context.Background(),
+		registry,
+		ToolCall{ID: "c1", Name: "flaky_probe"},
+		PermissionModeAuto,
+		Options{},
+	)
+	if abortErr != nil {
+		t.Fatal(abortErr)
+	}
+	if result.Risk.Level == "" {
+		t.Fatal("executed result must carry a risk classification")
+	}
+	if riskRank(result.Risk.Level) > riskRank(sandbox.RiskMedium) {
+		t.Fatalf("read-only tool classified %q, want at most medium", result.Risk.Level)
+	}
+}
+
+// TestUnknownToolResultCarriesZeroRisk verifies a call that never executed a
+// tool (unknown name, nil tool) keeps the zero risk value instead of panicking
+// or inventing a classification.
+func TestUnknownToolResultCarriesZeroRisk(t *testing.T) {
+	registry := tools.NewRegistry()
+	result, abortErr := executeToolCall(
+		context.Background(),
+		registry,
+		ToolCall{ID: "c1", Name: "no_such_tool"},
+		PermissionModeAuto,
+		Options{},
+	)
+	if abortErr != nil {
+		t.Fatal(abortErr)
+	}
+	if result.Status == tools.StatusOK {
+		t.Fatal("expected an error result for an unknown tool")
+	}
+	if result.Risk.Level != "" {
+		t.Fatalf("not-executed result must keep the zero risk value, got %q", result.Risk.Level)
+	}
+}

internal/agent/prompt_fingerprint.go

@@ -0,0 +1,244 @@
+package agent
+
+import (
+	"crypto/sha256"
+	"encoding/hex"
+	"encoding/json"
+	"fmt"
+	"sort"
+	"strings"
+
+	"github.com/Gitlawb/zero/internal/zeroruntime"
+)
+
+// promptSubstrings are the cacheable components of the prompt a run sends to a
+// model. systemPrompt is the exact joined system-message content. The remaining
+// fields retain useful diagnostic boundaries within that prompt and tool list.
+type promptSubstrings struct {
+	systemPrompt       string
+	baseInstructions   string
+	confirmationPolicy string
+	projectContext     string
+	skills             string
+	tools              string
+	schema             string
+}
+
+// buildPromptSubstrings builds the prompt and retains both its exact joined
+// form and narrower diagnostic components. Callers that already built the
+// prompt should use buildPromptSubstringsFromParts to avoid repeating workspace
+// reads.
+func buildPromptSubstrings(options Options, exposed []zeroruntime.ToolDefinition) promptSubstrings {
+	return buildPromptSubstringsFromParts(buildSystemPromptParts(options), exposed)
+}
+
+func buildPromptSubstringsFromParts(parts systemPromptParts, exposed []zeroruntime.ToolDefinition) promptSubstrings {
+	toolsSubstr, schemaSubstr := toolSubstrings(exposed)
+
+	return promptSubstrings{
+		systemPrompt:       parts.prompt,
+		baseInstructions:   parts.baseInstructions,
+		confirmationPolicy: parts.confirmationPolicy,
+		projectContext:     parts.projectContext,
+		skills:             parts.skills,
+		tools:              toolsSubstr,
+		schema:             schemaSubstr,
+	}
+}
+
+// toolSubstrings preserves the emitted tool order. Names and descriptions are
+// fingerprinted separately from schemas so either kind of drift is identifiable.
+// Order is part of request identity: silently sorting here would hide a provider-
+// visible reordering and could report a false cache hit.
+func toolSubstrings(exposed []zeroruntime.ToolDefinition) (toolsSubstr, schemaSubstr string) {
+	if len(exposed) == 0 {
+		return "", ""
+	}
+	var toolsSB, schemaSB strings.Builder
+	for _, def := range exposed {
+		writeLengthPrefixed(&toolsSB, def.Name)
+		writeLengthPrefixed(&toolsSB, def.Description)
+		// Parameters is rendered to a canonical JSON string per tool. The
+		// schema-render cache in internal/agent (used by partitionToolsCached)
+		// guarantees the same render is byte-identical across turns for the
+		// same tool, so this substring is a stable hash input.
+		writeLengthPrefixed(&schemaSB, def.Name)
+		writeLengthPrefixed(&schemaSB, canonicalSchemaString(def.Parameters))
+	}
+	return toolsSB.String(), schemaSB.String()
+}
+
+func writeLengthPrefixed(sb *strings.Builder, value string) {
+	fmt.Fprintf(sb, "%d:", len(value))
+	sb.WriteString(value)
+}
+
+// canonicalSchemaString renders a tool's parameter schema to a stable string.
+// tools.ToolDef.Parameters is a map[string]any in the common case; Go's
+// fmt.Sprintf("%v", m) iterates a map in random order, which would produce
+// a different hash for the same Parameters value across calls and defeat
+// the fingerprint. encoding/json marshals maps with keys sorted
+// alphabetically, so json.Marshal is the primary stable render. The
+// fallback for the rare non-JSON-compatible value (functions, channels,
+// NaN/Inf floats, cyclic references) is a stable key-sorted stringifier
+// that walks the value with sorted keys for maps and a leading
+// "__non_json:" prefix so a future schema change is visible in the trace
+// (a SchemaHash collision from the same value) rather than a silent hash
+// drift.
+//
+// Note: SchemaHash is a stability signal, not a wire-identity signal. The
+// bytes json.Marshal produces for a Go map[string]any may differ from
+// the bytes the provider actually sends on the wire (provider encoders
+// use their own JSON conventions; an Anthropic schema may serialize with
+// different whitespace, key order, or number formatting). A consumer
+// must NOT assume SchemaHash matches the provider's wire schema — only
+// that two turns with the same Go-side Parameters produce the same
+// SchemaHash. This is sufficient for the trace's purpose (drift
+// detection) but not for a content-based equality check.
+func canonicalSchemaString(params map[string]any) string {
+	if len(params) == 0 {
+		return ""
+	}
+	data, err := json.Marshal(params)
+	if err != nil {
+		return "__non_json:" + stableStringify(params)
+	}
+	return string(data)
+}
+
+// stableStringify renders v to a deterministic string. Maps have their keys
+// sorted alphabetically; slices are walked in order; primitives use their
+// natural Go format. The function is recursive but bounded by the size of
+// the input, so a cyclic reference is not reachable here (the json.Marshal
+// fallback is hit when json.Marshal itself returns an error, which for the
+// common case is a non-JSON-compatible value, not a cycle — cycles are
+// rare in tool schemas and acceptable to mis-render in the fallback path
+// since the trace's contract is "the hash is stable for the same input,"
+// not "the fallback is lossless"). Used only when json.Marshal fails.
+func stableStringify(v any) string {
+	var sb strings.Builder
+	writeStable(&sb, v)
+	return sb.String()
+}
+
+func writeStable(sb *strings.Builder, v any) {
+	switch x := v.(type) {
+	case nil:
+		sb.WriteString("null")
+	case bool:
+		if x {
+			sb.WriteString("true")
+		} else {
+			sb.WriteString("false")
+		}
+	case string:
+		sb.WriteByte('"')
+		sb.WriteString(x)
+		sb.WriteByte('"')
+	case float64:
+		// Use %g for compact, deterministic float rendering. NaN and Inf are
+		// not JSON-encodable (which is why we are in the fallback path) and
+		// render as "NaN" / "+Inf" / "-Inf" — distinct, stable strings.
+		fmt.Fprintf(sb, "%g", x)
+	case float32:
+		fmt.Fprintf(sb, "%g", float64(x))
+	case int:
+		fmt.Fprintf(sb, "%d", x)
+	case int64:
+		fmt.Fprintf(sb, "%d", x)
+	case int32:
+		fmt.Fprintf(sb, "%d", x)
+	case uint:
+		fmt.Fprintf(sb, "%d", x)
+	case uint64:
+		fmt.Fprintf(sb, "%d", x)
+	case uint32:
+		fmt.Fprintf(sb, "%d", x)
+	case map[string]any:
+		sb.WriteByte('{')
+		keys := make([]string, 0, len(x))
+		for k := range x {
+			keys = append(keys, k)
+		}
+		sort.Strings(keys)
+		for i, k := range keys {
+			if i > 0 {
+				sb.WriteByte(',')
+			}
+			sb.WriteByte('"')
+			sb.WriteString(k)
+			sb.WriteString(`":`)
+			writeStable(sb, x[k])
+		}
+		sb.WriteByte('}')
+	case []any:
+		sb.WriteByte('[')
+		for i, item := range x {
+			if i > 0 {
+				sb.WriteByte(',')
+			}
+			writeStable(sb, item)
+		}
+		sb.WriteByte(']')
+	default:
+		// Last-resort: include the type so distinct values produce distinct
+		// strings even if their default format collides. Without the type
+		// tag, fmt.Sprintf("%v", x) for two different types could produce
+		// the same bytes (rare, but the type prefix makes it impossible).
+		fmt.Fprintf(sb, "<%T:%v>", x, x)
+	}
+}
+
+// ComputePrefixFingerprint builds and fingerprints a prompt for callers that do
+// not already have one. The agent loop uses computePrefixFingerprint with the
+// prompt parts it built once at run start, ensuring tracing observes the exact
+// request content without repeating workspace I/O.
+func ComputePrefixFingerprint(options Options, exposed []zeroruntime.ToolDefinition) prefixFingerprint {
+	return computePrefixFingerprint(buildPromptSubstrings(options, exposed))
+}
+
+func computePrefixFingerprint(subs promptSubstrings) prefixFingerprint {
+	systemPrompt := sha256hex(subs.systemPrompt)
+	base := sha256hex(subs.baseInstructions)
+	policy := sha256hex(subs.confirmationPolicy)
+	project := sha256hex(subs.projectContext)
+	skills := sha256hex(subs.skills)
+	toolsH := sha256hex(subs.tools)
+	schema := sha256hex(subs.schema)
+	complete := sha256hex(strings.Join([]string{
+		systemPrompt, toolsH, schema,
+	}, "|"))
+	return prefixFingerprint{
+		SystemPromptHash:       systemPrompt,
+		BaseInstructionsHash:   base,
+		ConfirmationPolicyHash: policy,
+		ProjectContextHash:     project,
+		SkillsHash:             skills,
+		ToolsHash:              toolsH,
+		SchemaHash:             schema,
+		CompletePrefixHash:     complete,
+	}
+}
+
+// prefixFingerprint is the agent-side shape of a prompt-prefix fingerprint. It
+// is converted to a trace.PrefixHash at the loop boundary (see EmitPrefixHash
+// in loop.go) so the trace package does not need to import this one. The field
+// names match the trace.PrefixHash JSON tags 1:1.
+type prefixFingerprint struct {
+	SystemPromptHash       string
+	BaseInstructionsHash   string
+	ConfirmationPolicyHash string
+	ProjectContextHash     string
+	SkillsHash             string
+	ToolsHash              string
+	SchemaHash             string
+	CompletePrefixHash     string
+}
+
+// sha256hex returns the hex-encoded SHA-256 of s. Empty input produces the
+// hash of the empty string, which is a constant; callers that want to
+// distinguish "absent" from "empty" should check s before calling.
+func sha256hex(s string) string {
+	sum := sha256.Sum256([]byte(s))
+	return hex.EncodeToString(sum[:])
+}

internal/agent/prompt_fingerprint_test.go

@@ -0,0 +1,249 @@
+package agent
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/Gitlawb/zero/internal/zeroruntime"
+)
+
+// TestComputePrefixFingerprintStableAcrossCalls asserts the headline property
+// the trace is meant to expose: two ComputePrefixFingerprint calls over the
+// same Options and the same exposed tool list produce byte-identical hashes.
+// This is the regression catch for "did anyone introduce non-determinism into
+// the prompt prefix."
+func TestComputePrefixFingerprintStableAcrossCalls(t *testing.T) {
+	opts := Options{Cwd: t.TempDir(), SystemPrompt: "core"}
+	exposed := []zeroruntime.ToolDefinition{
+		{Name: "read_file", Parameters: map[string]any{"type": "object"}},
+		{Name: "grep", Parameters: map[string]any{"type": "object"}},
+	}
+	first := ComputePrefixFingerprint(opts, exposed)
+	second := ComputePrefixFingerprint(opts, exposed)
+	if first != second {
+		t.Fatalf("fingerprint must be stable across calls with the same input:\n  first=%+v\n second=%+v", first, second)
+	}
+	if first.CompletePrefixHash == "" {
+		t.Fatalf("CompletePrefixHash must be non-empty for a non-trivial prompt")
+	}
+}
+
+// Tool order and descriptions are provider-visible and therefore part of the
+// cacheable prefix identity.
+func TestComputePrefixFingerprintToolsHashMatchesEmittedOrderAndDescriptions(t *testing.T) {
+	opts := Options{Cwd: t.TempDir(), SystemPrompt: "core"}
+	a := []zeroruntime.ToolDefinition{
+		{Name: "read_file", Description: "read", Parameters: map[string]any{"schema": "schema-read"}},
+		{Name: "grep", Description: "search", Parameters: map[string]any{"schema": "schema-grep"}},
+	}
+	b := []zeroruntime.ToolDefinition{
+		{Name: "grep", Description: "search", Parameters: map[string]any{"schema": "schema-grep"}},
+		{Name: "read_file", Description: "read", Parameters: map[string]any{"schema": "schema-read"}},
+	}
+	fpA := ComputePrefixFingerprint(opts, a)
+	fpB := ComputePrefixFingerprint(opts, b)
+	if fpA.ToolsHash == fpB.ToolsHash {
+		t.Fatalf("ToolsHash must change when emitted order changes: a=%s b=%s", fpA.ToolsHash, fpB.ToolsHash)
+	}
+	c := append([]zeroruntime.ToolDefinition(nil), a...)
+	c[0].Description = "read a file"
+	fpC := ComputePrefixFingerprint(opts, c)
+	if fpA.ToolsHash == fpC.ToolsHash {
+		t.Fatalf("ToolsHash must change when a description changes: a=%s c=%s", fpA.ToolsHash, fpC.ToolsHash)
+	}
+}
+
+// TestComputePrefixFingerprintSchemaChangeChangesSchemaHash asserts that a
+// change to a tool's Parameters schema is visible in the SchemaHash. A schema
+// edit that should be cache-stable (e.g. field reorder, doc tweak) will move
+// the hash and surface in the trace; a schema edit that legitimately
+// invalidates the cache also moves the hash, which is the right behavior.
+func TestComputePrefixFingerprintSchemaChangeChangesSchemaHash(t *testing.T) {
+	opts := Options{Cwd: t.TempDir(), SystemPrompt: "core"}
+	a := []zeroruntime.ToolDefinition{
+		{Name: "read_file", Parameters: map[string]any{"version": "v1"}},
+	}
+	b := []zeroruntime.ToolDefinition{
+		{Name: "read_file", Parameters: map[string]any{"version": "v2"}},
+	}
+	fpA := ComputePrefixFingerprint(opts, a)
+	fpB := ComputePrefixFingerprint(opts, b)
+	if fpA.SchemaHash == fpB.SchemaHash {
+		t.Fatalf("SchemaHash must change when tool Parameters change: a=%s b=%s", fpA.SchemaHash, fpB.SchemaHash)
+	}
+}
+
+// TestComputePrefixFingerprintSystemPromptChangeChangesBaseHash asserts the
+// most common drift path: a system-prompt edit (e.g. an agent.md update, a
+// model addendum change) must move the base-instructions hash, which moves
+// the complete-prefix hash, which is what the trace is for.
+func TestComputePrefixFingerprintSystemPromptChangeChangesBaseHash(t *testing.T) {
+	optsA := Options{Cwd: t.TempDir(), SystemPrompt: "core v1"}
+	optsB := Options{Cwd: t.TempDir(), SystemPrompt: "core v2"}
+	exposed := []zeroruntime.ToolDefinition{{Name: "noop", Parameters: map[string]any{}}}
+	fpA := ComputePrefixFingerprint(optsA, exposed)
+	fpB := ComputePrefixFingerprint(optsB, exposed)
+	if fpA.BaseInstructionsHash == fpB.BaseInstructionsHash {
+		t.Fatalf("BaseInstructionsHash must change when SystemPrompt changes: a=%s b=%s", fpA.BaseInstructionsHash, fpB.BaseInstructionsHash)
+	}
+	if fpA.CompletePrefixHash == fpB.CompletePrefixHash {
+		t.Fatalf("CompletePrefixHash must change when any sub-hash changes: a=%s b=%s", fpA.CompletePrefixHash, fpB.CompletePrefixHash)
+	}
+}
+
+// CompletePrefixHash represents the exact joined system prompt and the ordered
+// tool definitions. Narrower system-section hashes remain diagnostic only.
+func TestComputePrefixFingerprintCompleteIsAggregateOfSubHashes(t *testing.T) {
+	opts := Options{Cwd: t.TempDir(), SystemPrompt: "core"}
+	exposed := []zeroruntime.ToolDefinition{{Name: "read_file", Parameters: map[string]any{"k": "v"}}}
+	fp := ComputePrefixFingerprint(opts, exposed)
+	// Manually compute what the canonical join should be.
+	expected := sha256hex(strings.Join([]string{
+		fp.SystemPromptHash,
+		fp.ToolsHash,
+		fp.SchemaHash,
+	}, "|"))
+	if fp.CompletePrefixHash != expected {
+		t.Fatalf("CompletePrefixHash must equal sha256hex of the exact system, tools, and schema hashes:\n  got:      %s\n  expected: %s", fp.CompletePrefixHash, expected)
+	}
+}
+
+func TestComputePrefixFingerprintCoversEverySystemPromptSection(t *testing.T) {
+	base := Options{Cwd: t.TempDir(), SystemPrompt: "core", Model: "gpt-5"}
+	changed := base
+	changed.ResponseStyle = "concise"
+
+	fpBase := ComputePrefixFingerprint(base, nil)
+	fpChanged := ComputePrefixFingerprint(changed, nil)
+	if fpBase.SystemPromptHash == fpChanged.SystemPromptHash {
+		t.Fatal("SystemPromptHash must change when any rendered system section changes")
+	}
+	if fpBase.CompletePrefixHash == fpChanged.CompletePrefixHash {
+		t.Fatal("CompletePrefixHash must include the exact full system prompt")
+	}
+}
+
+// TestBuildPromptSubstringsDefaultOptions asserts the invariants of the
+// substrings helper for default Options: which substrings are non-empty,
+// which are empty, and that the substring-to-hash round-trip is lossless.
+func TestBuildPromptSubstringsDefaultOptions(t *testing.T) {
+	opts := Options{
+		Cwd:          t.TempDir(),
+		SystemPrompt: "test core",
+	}
+	subs := buildPromptSubstrings(opts, nil)
+	// Invariants the trace depends on (default Options):
+	//   1. baseInstructions substring equals the core system prompt bytes.
+	//   2. confirmationPolicy substring is non-empty (the embedded policy
+	//      is always present, post TrimSpace).
+	//   3. skills, tools, and schema substrings are empty (no skills or
+	//      tools configured for default Options).
+	if subs.baseInstructions != "test core" {
+		t.Fatalf("baseInstructions substring must equal the core system prompt: got %q want %q", subs.baseInstructions, "test core")
+	}
+	if subs.systemPrompt != buildSystemPrompt(opts) {
+		t.Fatal("systemPrompt substring must equal the exact joined system prompt")
+	}
+	if subs.confirmationPolicy == "" {
+		t.Fatalf("confirmationPolicy substring must be non-empty (the embedded policy is always present)")
+	}
+	if subs.skills != "" {
+		t.Fatalf("skills substring must be empty for default Options: got %q", subs.skills)
+	}
+	// Round-trip: the corresponding fingerprint hashes must equal
+	// sha256hex of the substrings, with no truncation or reformatting
+	// between the two layers.
+	fp := ComputePrefixFingerprint(opts, nil)
+	if fp.SystemPromptHash != sha256hex(subs.systemPrompt) {
+		t.Fatalf("SystemPromptHash in fingerprint must equal sha256hex of the joined prompt")
+	}
+	if fp.BaseInstructionsHash != sha256hex(subs.baseInstructions) {
+		t.Fatalf("BaseInstructionsHash in fingerprint must equal sha256hex of the substring")
+	}
+	if fp.ConfirmationPolicyHash != sha256hex(subs.confirmationPolicy) {
+		t.Fatalf("ConfirmationPolicyHash in fingerprint must equal sha256hex of the substring")
+	}
+}
+
+// TestCanonicalSchemaStringStableForMapParameters asserts the headline
+// property the trace needs: the same map[string]any produces the same
+// canonical string across calls, even though Go's fmt.Sprintf("%v", m)
+// iterates a map in random order. json.Marshal sorts map keys
+// alphabetically, which is the fix.
+func TestCanonicalSchemaStringStableForMapParameters(t *testing.T) {
+	params := map[string]any{
+		"description": "read a file",
+		"properties": map[string]any{
+			"path": map[string]any{"type": "string"},
+		},
+		"required": []any{"path"},
+		"type":     "object",
+	}
+	first := canonicalSchemaString(params)
+	second := canonicalSchemaString(params)
+	if first != second {
+		t.Fatalf("canonicalSchemaString must be stable across calls for the same Parameters:\n  first=%s\n second=%s", first, second)
+	}
+	if first == "" {
+		t.Fatal("canonicalSchemaString must produce a non-empty string for a non-empty map")
+	}
+	// Two maps with the same key/value pairs (different declaration
+	// order in source) must produce identical canonical strings. This
+	// is the property that defeats Go's map iteration randomization.
+	reordered := map[string]any{
+		"type":     "object",
+		"required": []any{"path"},
+		"properties": map[string]any{
+			"path": map[string]any{"type": "string"},
+		},
+		"description": "read a file",
+	}
+	if canonicalSchemaString(params) != canonicalSchemaString(reordered) {
+		t.Fatal("canonicalSchemaString must produce identical output for maps with the same key/value pairs in different declaration orders")
+	}
+}
+
+// TestCanonicalSchemaStringFallbackStableForNonJSONValue exercises the
+// non-JSON fallback in canonicalSchemaString: when Parameters contains a
+// value json.Marshal cannot encode (here, a channel), the function must
+// fall back to a key-sorted stringification that is stable across calls
+// and across map-iteration order. The previous fallback used
+// fmt.Sprintf("%v", params), which iterates the map in random order and
+// produced a different hash for the same value across calls — defeating
+// the fingerprint. The current fallback is stable by construction.
+func TestCanonicalSchemaStringFallbackStableForNonJSONValue(t *testing.T) {
+	ch := make(chan int) // channels are not JSON-encodable
+	params := map[string]any{
+		"description": "a tool with a non-JSON value",
+		"channel":     ch,
+		"z_first":     1,
+		"a_second":    2,
+	}
+	first := canonicalSchemaString(params)
+	second := canonicalSchemaString(params)
+	if first == "" {
+		t.Fatal("canonicalSchemaString must produce a non-empty string for the fallback path")
+	}
+	if first != second {
+		t.Fatalf("canonicalSchemaString fallback must be stable across calls:\n  first=%s\n second=%s", first, second)
+	}
+	// A re-ordered map (same key/value pairs, different declaration order)
+	// must produce the same fallback string. This is the property the
+	// key-sorted stringifier provides that fmt.Sprintf("%v", m) does not.
+	reordered := map[string]any{
+		"a_second":    2,
+		"z_first":     1,
+		"channel":     ch,
+		"description": "a tool with a non-JSON value",
+	}
+	if canonicalSchemaString(params) != canonicalSchemaString(reordered) {
+		t.Fatalf("canonicalSchemaString fallback must produce identical output for maps with the same key/value pairs in different declaration orders:\n  first=%s\n second=%s", first, canonicalSchemaString(reordered))
+	}
+	// The fallback must include the "__non_json:" prefix so a consumer
+	// can tell the bytes are not a JSON-marshaled schema (a hash collision
+	// between a json.Marshal result and a stableStringify result is
+	// possible in theory; the prefix makes the source observable).
+	if !strings.HasPrefix(first, "__non_json:") {
+		t.Fatalf("canonicalSchemaString fallback must start with the __non_json: prefix, got: %s", first)
+	}
+}

internal/agent/reconnect.go

@@ -8,6 +8,7 @@ import (
 	"time"
 
 	"github.com/Gitlawb/zero/internal/errhint"
+	"github.com/Gitlawb/zero/internal/trace"
 	"github.com/Gitlawb/zero/internal/zeroruntime"
 )
 
@@ -74,14 +75,21 @@ func stallRetryNoticeFor(options Options) reconnectNotifier {
 // already past its deadline is returned immediately (no retry) — those have
 // their own handling (compaction for context-limit, image-rejection, etc.).
 func streamWithReconnect(ctx context.Context, provider Provider, request zeroruntime.CompletionRequest, notify reconnectNotifier) (<-chan zeroruntime.StreamEvent, error) {
+	recorder := trace.FromContext(ctx)
 	stream, err := provider.StreamCompletion(ctx, request)
 	if err == nil {
+		if recorder != nil {
+			recorder.Counter(trace.CounterModelRequests, 1)
+		}
 		return stream, nil
 	}
 	for attempt := 1; attempt <= maxStreamReconnects; attempt++ {
 		if !shouldReconnect(ctx, err) {
 			return nil, err
 		}
+		if recorder != nil {
+			recorder.Counter(trace.CounterReconnectCount, 1)
+		}
 		if notify != nil {
 			notify(attempt, maxStreamReconnects)
 		}
@@ -90,6 +98,9 @@ func streamWithReconnect(ctx context.Context, provider Provider, request zerorun
 		}
 		stream, err = provider.StreamCompletion(ctx, request)
 		if err == nil {
+			if recorder != nil {
+				recorder.Counter(trace.CounterModelRequests, 1)
+			}
 			return stream, nil
 		}
 	}

internal/agent/selfcorrect.go

@@ -9,6 +9,7 @@ import (
 
 	"github.com/Gitlawb/zero/internal/lsp"
 	"github.com/Gitlawb/zero/internal/redaction"
+	"github.com/Gitlawb/zero/internal/trace"
 	"github.com/Gitlawb/zero/internal/verify"
 )
 
@@ -133,7 +134,9 @@ func (sc *SelfCorrector) inspect(ctx context.Context, changedFiles []string) Cor
 	}
 
 	if sc.cfg.IncludeTests && sc.verifier != nil {
+		verifySpan := trace.FromContext(ctx).Span(trace.SpanVerification)
 		vr, err := sc.verifier.Verify(ctx)
+		verifySpan.End()
 		if err != nil {
 			// "No plan / no tests" is not an error (DetectPlan returns an empty
 			// plan), so a non-nil error means verification could not run at all —

internal/agent/system_prompt.go

@@ -70,6 +70,22 @@ const (
 // guidelines), and the safety confirmation policy. It is built once per run so
 // every turn shares one (cacheable) system turn.
 func buildSystemPrompt(options Options) string {
+	return buildSystemPromptParts(options).prompt
+}
+
+// systemPromptParts retains both the exact joined prompt and the diagnostic
+// sections used by prompt-prefix tracing. Building these together prevents the
+// tracing path from re-reading workspace state and guarantees that the hash is
+// computed from the same prompt bytes placed in the request.
+type systemPromptParts struct {
+	prompt             string
+	baseInstructions   string
+	confirmationPolicy string
+	projectContext     string
+	skills             string
+}
+
+func buildSystemPromptParts(options Options) systemPromptParts {
 	core := strings.TrimSpace(options.SystemPrompt)
 	if core == "" {
 		core = strings.TrimSpace(coreSystemPrompt)
@@ -97,22 +113,31 @@ func buildSystemPrompt(options Options) string {
 	if user := userGuidelines(); user != "" {
 		sections = append(sections, user)
 	}
-	if ws := workspaceContext(options.Cwd); ws != "" {
-		sections = append(sections, ws)
+	project := workspaceContext(options.Cwd)
+	if project != "" {
+		sections = append(sections, project)
 	}
 	if delegation := specialistDelegationContext(options); delegation != "" {
 		sections = append(sections, delegation)
 	}
-	if skillsBlock := skillsContext(options); skillsBlock != "" {
+	skillsBlock := skillsContext(options)
+	if skillsBlock != "" {
 		sections = append(sections, skillsBlock)
 	}
 	if style := responseStyleContext(options); style != "" {
 		sections = append(sections, style)
 	}
-	if policy := strings.TrimSpace(confirmationPolicy); policy != "" {
+	policy := strings.TrimSpace(confirmationPolicy)
+	if policy != "" {
 		sections = append(sections, policy)
 	}
-	return strings.Join(sections, "\n\n")
+	return systemPromptParts{
+		prompt:             strings.Join(sections, "\n\n"),
+		baseInstructions:   core,
+		confirmationPolicy: policy,
+		projectContext:     project,
+		skills:             skillsBlock,
+	}
 }
 
 // responseStyleContext renders the operator-selected reply style (TUI /style) as

internal/agent/system_prompt.md

@@ -100,6 +100,9 @@ work.
 - Use exec_command with `tty: true` for interactive terminal-style commands that
   need stdin beyond Ctrl-C. `/ps` and `/stop` are user-facing TUI commands; when
   you need to clean up a running foreground command yourself, use write_stdin.
+- write_stdin's session_id is only ever an id returned by a still-running
+  exec_command; never guess or probe ids. If you have no such session, start one
+  with exec_command, or use write_file/edit_file/apply_patch for file changes.
 - write_stdin with empty input polls an existing exec_command session, and
   `\u0003` interrupts it. Sending other stdin bytes may require approval because
   it can drive the running process beyond the original command. Non-tty sessions

internal/agent/task_state.go

@@ -0,0 +1,359 @@
+package agent
+
+import (
+	"encoding/json"
+	"reflect"
+	"sort"
+	"strings"
+
+	"github.com/Gitlawb/zero/internal/tools"
+	"github.com/Gitlawb/zero/internal/trace"
+	"github.com/Gitlawb/zero/internal/zeroruntime"
+)
+
+type taskStatus string
+
+const (
+	taskStatusActive     taskStatus = "active"
+	taskStatusComplete   taskStatus = "complete"
+	taskStatusIncomplete taskStatus = "incomplete"
+)
+
+type taskPlanParity string
+
+const (
+	taskPlanParityUnknown  taskPlanParity = "unknown"
+	taskPlanParityMatch    taskPlanParity = "match"
+	taskPlanParityMismatch taskPlanParity = "mismatch"
+)
+
+type taskPlanItem struct {
+	Content string `json:"content"`
+	Status  string `json:"status"`
+	Notes   string `json:"notes,omitempty"`
+}
+
+type taskPlanState struct {
+	Items      []taskPlanItem `json:"items,omitempty"`
+	Pending    int            `json:"pending"`
+	InProgress int            `json:"in_progress"`
+	Completed  int            `json:"completed"`
+	Failed     int            `json:"failed"`
+}
+
+type taskToolState struct {
+	Succeeded int `json:"succeeded"`
+	Failed    int `json:"failed"`
+}
+
+type taskVerificationState struct {
+	Passed      int     `json:"passed"`
+	Failed      int     `json:"failed"`
+	LastOutcome Outcome `json:"last_outcome,omitempty"`
+}
+
+type taskStateSnapshot struct {
+	Revision           int                   `json:"revision"`
+	Objective          string                `json:"objective"`
+	Status             taskStatus            `json:"status"`
+	Plan               taskPlanState         `json:"plan"`
+	Tools              taskToolState         `json:"tools"`
+	Verification       taskVerificationState `json:"verification"`
+	ChangedFiles       []string              `json:"changed_files,omitempty"`
+	CompletionDecision CompletionDecision    `json:"completion_decision,omitempty"`
+	CompletionReason   string                `json:"completion_reason,omitempty"`
+	PlanParity         taskPlanParity        `json:"plan_parity"`
+}
+
+type taskStateEventKind int
+
+const (
+	taskStateEventPlan taskStateEventKind = iota + 1
+	taskStateEventToolResult
+	taskStateEventVerification
+	taskStateEventCompletion
+)
+
+type taskStateEvent struct {
+	kind         taskStateEventKind
+	arguments    string
+	toolResult   ToolResult
+	verification Outcome
+	completion   completionEvaluation
+}
+
+// taskState is a deterministic projection of facts the loop already observes.
+// It does not initiate work or replace the transcript; consumers must check
+// transcript parity before using its compact representation.
+type taskState struct {
+	snapshotValue taskStateSnapshot
+	changedFiles  map[string]struct{}
+	recorder      *trace.Recorder
+	planObserved  bool
+}
+
+func newTaskState(objective string, recorder *trace.Recorder) *taskState {
+	state := &taskState{
+		snapshotValue: taskStateSnapshot{
+			Objective:  strings.TrimSpace(objective),
+			Status:     taskStatusActive,
+			PlanParity: taskPlanParityUnknown,
+		},
+		changedFiles: map[string]struct{}{},
+	}
+	state.recorder = recorder
+	return state
+}
+
+func (state *taskState) observe(event taskStateEvent) bool {
+	if state == nil {
+		return false
+	}
+	changed := false
+	switch event.kind {
+	case taskStateEventPlan:
+		plan, ok := parseTaskPlan(event.arguments)
+		if !ok {
+			return false
+		}
+		state.snapshotValue.Plan = summarizeTaskPlan(plan)
+		state.planObserved = true
+		state.markActive()
+		changed = true
+	case taskStateEventToolResult:
+		state.markActive()
+		if event.toolResult.Status == tools.StatusOK {
+			state.snapshotValue.Tools.Succeeded++
+		} else {
+			state.snapshotValue.Tools.Failed++
+		}
+		for _, path := range event.toolResult.ChangedFiles {
+			path = strings.TrimSpace(path)
+			if path != "" {
+				state.changedFiles[path] = struct{}{}
+			}
+		}
+		state.snapshotValue.ChangedFiles = sortedKeys(state.changedFiles)
+		changed = true
+	case taskStateEventVerification:
+		if event.verification == OutcomeDisabled {
+			return false
+		}
+		state.markActive()
+		state.snapshotValue.Verification.LastOutcome = event.verification
+		switch event.verification {
+		case OutcomePassed:
+			state.snapshotValue.Verification.Passed++
+		case OutcomeCorrecting, OutcomeReported, OutcomeAborted:
+			state.snapshotValue.Verification.Failed++
+		}
+		changed = true
+	case taskStateEventCompletion:
+		state.snapshotValue.CompletionDecision = event.completion.Decision
+		state.snapshotValue.CompletionReason = event.completion.Reason
+		switch event.completion.Decision {
+		case CompletionComplete:
+			state.snapshotValue.Status = taskStatusComplete
+		case CompletionIncomplete:
+			state.snapshotValue.Status = taskStatusIncomplete
+		default:
+			state.snapshotValue.Status = taskStatusActive
+		}
+		changed = true
+	}
+	if changed {
+		state.snapshotValue.Revision++
+		if event.kind != taskStateEventToolResult {
+			state.emit()
+		}
+	}
+	return changed
+}
+
+func (state *taskState) markActive() {
+	state.snapshotValue.Status = taskStatusActive
+	state.snapshotValue.CompletionDecision = ""
+	state.snapshotValue.CompletionReason = ""
+}
+
+func (state *taskState) snapshot() taskStateSnapshot {
+	if state == nil {
+		return taskStateSnapshot{}
+	}
+	snapshot := state.snapshotValue
+	snapshot.Plan.Items = append([]taskPlanItem(nil), state.snapshotValue.Plan.Items...)
+	snapshot.ChangedFiles = append([]string(nil), state.snapshotValue.ChangedFiles...)
+	return snapshot
+}
+
+// observePlanParity compares only the latest plan projection with the plan tool
+// calls still present in messages. It mutates the snapshot and emits when the
+// parity value changes; objective, tool, and verification fields are not part of
+// this comparison.
+func (state *taskState) observePlanParity(messages []zeroruntime.Message) taskPlanParity {
+	if state == nil {
+		return taskPlanParityUnknown
+	}
+	transcriptPlan, found, valid := latestTaskPlan(messages)
+	tracked := state.snapshotValue.Plan.Items
+	parity := taskPlanParityMatch
+	if !valid || found != state.planObserved || (found && !reflect.DeepEqual(transcriptPlan, tracked)) {
+		parity = taskPlanParityMismatch
+	}
+	if state.snapshotValue.PlanParity != parity {
+		state.snapshotValue.PlanParity = parity
+		state.snapshotValue.Revision++
+		state.emit()
+	}
+	return parity
+}
+
+type completionContext struct {
+	Objective             string
+	PlanPending           bool
+	PlanMatchesTranscript bool
+}
+
+func (state *taskState) completionContext(messages []zeroruntime.Message, transcriptPlanPending bool) completionContext {
+	context := completionContext{PlanPending: transcriptPlanPending}
+	if state == nil {
+		return context
+	}
+	context.Objective = state.snapshotValue.Objective
+	context.PlanMatchesTranscript = state.observePlanParity(messages) == taskPlanParityMatch
+	if context.PlanMatchesTranscript {
+		context.PlanPending = state.snapshotValue.Plan.Pending+state.snapshotValue.Plan.InProgress > 0
+	}
+	return context
+}
+
+func (state *taskState) snapshotForCompaction(messages []zeroruntime.Message) *taskStateSnapshot {
+	if state == nil {
+		return nil
+	}
+	state.observePlanParity(messages)
+	snapshot := state.snapshot()
+	return &snapshot
+}
+
+func (state *taskState) emit() {
+	if state == nil || state.recorder == nil {
+		return
+	}
+	snapshot := state.snapshotValue
+	state.recorder.EmitTaskState(trace.TaskStateEvent{
+		Revision:            snapshot.Revision,
+		Status:              string(snapshot.Status),
+		PlanPending:         snapshot.Plan.Pending,
+		PlanInProgress:      snapshot.Plan.InProgress,
+		PlanCompleted:       snapshot.Plan.Completed,
+		PlanFailed:          snapshot.Plan.Failed,
+		ToolsSucceeded:      snapshot.Tools.Succeeded,
+		ToolsFailed:         snapshot.Tools.Failed,
+		VerificationPassed:  snapshot.Verification.Passed,
+		VerificationFailed:  snapshot.Verification.Failed,
+		VerificationOutcome: string(snapshot.Verification.LastOutcome),
+		ChangedFileCount:    len(snapshot.ChangedFiles),
+		CompletionDecision:  string(snapshot.CompletionDecision),
+		PlanParity:          string(snapshot.PlanParity),
+	})
+}
+
+func parseTaskPlan(arguments string) ([]taskPlanItem, bool) {
+	var object map[string]json.RawMessage
+	if json.Unmarshal([]byte(strings.TrimSpace(arguments)), &object) != nil {
+		return nil, false
+	}
+	rawPlan, ok := object["plan"]
+	if !ok || string(rawPlan) == "null" {
+		return nil, false
+	}
+	var parsed []struct {
+		ID      *string `json:"id"`
+		Content string  `json:"content"`
+		Status  string  `json:"status"`
+		Notes   string  `json:"notes"`
+	}
+	if json.Unmarshal(rawPlan, &parsed) != nil {
+		return nil, false
+	}
+	plan := make([]taskPlanItem, 0, len(parsed))
+	for _, raw := range parsed {
+		if raw.Content == "" {
+			return nil, false
+		}
+		plan = append(plan, taskPlanItem{
+			Content: raw.Content,
+			Status:  normalizeTaskPlanStatus(raw.Status),
+			Notes:   raw.Notes,
+		})
+	}
+	lastInProgress := -1
+	for index := range plan {
+		if plan[index].Status == "in_progress" {
+			if lastInProgress >= 0 {
+				plan[lastInProgress].Status = "completed"
+			}
+			lastInProgress = index
+		}
+	}
+	if len(plan) == 0 {
+		return nil, true
+	}
+	return plan, true
+}
+
+func normalizeTaskPlanStatus(status string) string {
+	switch strings.ToLower(strings.TrimSpace(status)) {
+	case "completed", "complete", "done", "finished", "resolved", "✓", "x", "[x]":
+		return "completed"
+	case "in_progress", "in-progress", "inprogress", "in progress", "active", "doing", "started", "current", "wip", "ongoing", "running":
+		return "in_progress"
+	case "failed", "fail", "error", "errored", "blocked", "cancelled", "canceled", "abandoned", "skipped":
+		return "failed"
+	default:
+		return "pending"
+	}
+}
+
+func summarizeTaskPlan(items []taskPlanItem) taskPlanState {
+	plan := taskPlanState{Items: append([]taskPlanItem(nil), items...)}
+	for _, item := range items {
+		switch item.Status {
+		case "completed":
+			plan.Completed++
+		case "in_progress":
+			plan.InProgress++
+		case "failed":
+			plan.Failed++
+		default:
+			plan.Pending++
+		}
+	}
+	return plan
+}
+
+func latestTaskPlan(messages []zeroruntime.Message) ([]taskPlanItem, bool, bool) {
+	for i := len(messages) - 1; i >= 0; i-- {
+		for j := len(messages[i].ToolCalls) - 1; j >= 0; j-- {
+			call := messages[i].ToolCalls[j]
+			if call.Name != planToolName {
+				continue
+			}
+			plan, ok := parseTaskPlan(call.Arguments)
+			return plan, true, ok
+		}
+	}
+	return nil, false, true
+}
+
+func sortedKeys(values map[string]struct{}) []string {
+	keys := make([]string, 0, len(values))
+	for value := range values {
+		keys = append(keys, value)
+	}
+	// Paths are evidence, not chronology. Stable ordering makes replay snapshots
+	// deterministic even if events originate from parallel read batches later.
+	sort.Strings(keys)
+	return keys
+}

internal/agent/task_state_test.go

@@ -0,0 +1,204 @@
+package agent
+
+import (
+	"context"
+	"reflect"
+	"testing"
+
+	"github.com/Gitlawb/zero/internal/tools"
+	"github.com/Gitlawb/zero/internal/trace"
+	"github.com/Gitlawb/zero/internal/zeroruntime"
+)
+
+func TestTaskStateReplayIsDeterministic(t *testing.T) {
+	events := []taskStateEvent{
+		{kind: taskStateEventPlan, arguments: `{"plan":[{"content":"inspect","status":"done"},{"content":"implement","status":"in progress"},{"content":"verify"}]}`},
+		{kind: taskStateEventToolResult, toolResult: ToolResult{Name: "apply_patch", Status: tools.StatusOK, ChangedFiles: []string{"a.go", "a.go", "b.go"}}},
+		{kind: taskStateEventToolResult, toolResult: ToolResult{Name: "go test", Status: tools.StatusError}},
+		{kind: taskStateEventVerification, verification: OutcomePassed},
+		{kind: taskStateEventCompletion, completion: completionEvaluation{Decision: CompletionUncertain, Reason: "pending work"}},
+	}
+
+	first := newTaskState("ship the change", nil)
+	second := newTaskState("ship the change", nil)
+	for _, event := range events {
+		first.observe(event)
+		second.observe(event)
+	}
+
+	if !reflect.DeepEqual(first.snapshot(), second.snapshot()) {
+		t.Fatalf("replaying the same events produced different snapshots:\nfirst:  %#v\nsecond: %#v", first.snapshot(), second.snapshot())
+	}
+	got := first.snapshot()
+	if got.Status != taskStatusActive || got.Plan.Pending != 1 || got.Plan.InProgress != 1 || got.Plan.Completed != 1 {
+		t.Fatalf("unexpected plan snapshot: %#v", got)
+	}
+	if got.Tools.Succeeded != 1 || got.Tools.Failed != 1 || len(got.ChangedFiles) != 2 {
+		t.Fatalf("unexpected evidence snapshot: %#v", got)
+	}
+	if got.Verification.Passed != 1 || got.Verification.Failed != 0 || got.Verification.LastOutcome != OutcomePassed {
+		t.Fatalf("unexpected verification snapshot: %#v", got.Verification)
+	}
+}
+
+func TestTaskStateCoalescesToolResultsIntoNextTraceEvent(t *testing.T) {
+	recorder := trace.NewRecorder("session", "run", "")
+	state := newTaskState("objective", recorder)
+	for range 20 {
+		state.observe(taskStateEvent{kind: taskStateEventToolResult, toolResult: ToolResult{Status: tools.StatusOK}})
+	}
+	if events := recorder.Finish().TaskStates; len(events) != 0 {
+		t.Fatalf("tool results should be coalesced, got %d trace events", len(events))
+	}
+
+	recorder = trace.NewRecorder("session", "run-2", "")
+	state = newTaskState("objective", recorder)
+	for range 20 {
+		state.observe(taskStateEvent{kind: taskStateEventToolResult, toolResult: ToolResult{Status: tools.StatusOK}})
+	}
+	state.observe(taskStateEvent{kind: taskStateEventCompletion, completion: completionEvaluation{Decision: CompletionComplete}})
+	events := recorder.Finish().TaskStates
+	if len(events) != 1 || events[0].ToolsSucceeded != 20 {
+		t.Fatalf("coalesced tool total missing from completion snapshot: %#v", events)
+	}
+}
+
+func TestRunEmitsTaskStateFromExistingLoopEvents(t *testing.T) {
+	registry := tools.NewRegistry()
+	registry.Register(tools.NewUpdatePlanTool())
+	provider := &mockProvider{turns: [][]zeroruntime.StreamEvent{
+		{
+			{Type: zeroruntime.StreamEventToolCallStart, ToolCallID: "plan-1", ToolName: planToolName},
+			{Type: zeroruntime.StreamEventToolCallDelta, ToolCallID: "plan-1", ArgumentsFragment: `{"plan":[{"content":"implement","status":"completed"}]}`},
+			{Type: zeroruntime.StreamEventToolCallEnd, ToolCallID: "plan-1"},
+			{Type: zeroruntime.StreamEventDone},
+		},
+		{
+			{Type: zeroruntime.StreamEventText, Content: "done"},
+			{Type: zeroruntime.StreamEventDone},
+		},
+	}}
+	recorder := trace.NewRecorder("session", "run", "")
+
+	result, err := Run(context.Background(), "implement the change", provider, Options{
+		Registry: registry,
+		Trace:    recorder,
+	})
+	if err != nil {
+		t.Fatalf("Run: %v", err)
+	}
+	if result.FinalAnswer != "done" {
+		t.Fatalf("final answer = %q, want done", result.FinalAnswer)
+	}
+	events := recorder.Finish().TaskStates
+	if len(events) < 3 {
+		t.Fatalf("expected plan, tool, completion, and parity snapshots, got %#v", events)
+	}
+	last := events[len(events)-1]
+	if last.Status != string(taskStatusComplete) || last.PlanCompleted != 1 || last.ToolsSucceeded != 1 || last.PlanParity != string(taskPlanParityMatch) {
+		t.Fatalf("unexpected final task snapshot: %#v", last)
+	}
+}
+
+func TestTaskStateSnapshotIsImmutable(t *testing.T) {
+	state := newTaskState("objective", nil)
+	state.observe(taskStateEvent{kind: taskStateEventPlan, arguments: `{"plan":[{"content":"one","status":"pending"}]}`})
+	state.observe(taskStateEvent{kind: taskStateEventToolResult, toolResult: ToolResult{Status: tools.StatusOK, ChangedFiles: []string{"one.go"}}})
+
+	snapshot := state.snapshot()
+	snapshot.Plan.Items[0].Content = "mutated"
+	snapshot.ChangedFiles[0] = "mutated.go"
+
+	fresh := state.snapshot()
+	if fresh.Plan.Items[0].Content != "one" || fresh.ChangedFiles[0] != "one.go" {
+		t.Fatalf("snapshot mutation leaked into task state: %#v", fresh)
+	}
+}
+
+func TestTaskStatePlanParityUsesLatestPlan(t *testing.T) {
+	state := newTaskState("objective", nil)
+	state.observe(taskStateEvent{kind: taskStateEventPlan, arguments: `{"plan":[{"content":"old","status":"completed"}]}`})
+	state.observe(taskStateEvent{kind: taskStateEventPlan, arguments: `{"plan":[{"content":"new","status":"in_progress"}]}`})
+
+	messages := []zeroruntime.Message{{Role: zeroruntime.MessageRoleAssistant, ToolCalls: []zeroruntime.ToolCall{
+		{Name: planToolName, Arguments: `{"plan":[{"content":"new","status":"in_progress"}]}`},
+	}}}
+	if parity := state.observePlanParity(messages); parity != taskPlanParityMatch {
+		t.Fatalf("parity = %q, want match", parity)
+	}
+
+	messages[0].ToolCalls[0].Arguments = `{"plan":[{"content":"different","status":"pending"}]}`
+	if parity := state.observePlanParity(messages); parity != taskPlanParityMismatch {
+		t.Fatalf("parity = %q, want mismatch", parity)
+	}
+}
+
+func TestTaskStateMatchesPlanToolNormalization(t *testing.T) {
+	state := newTaskState("objective", nil)
+	arguments := `{"plan":[{"content":"first","status":"in_progress"},{"content":"second","status":"in_progress"}]}`
+	state.observe(taskStateEvent{kind: taskStateEventPlan, arguments: arguments})
+
+	snapshot := state.snapshot()
+	if snapshot.Plan.Completed != 1 || snapshot.Plan.InProgress != 1 {
+		t.Fatalf("multiple active items were not normalized like the plan tool: %#v", snapshot.Plan)
+	}
+	messages := []zeroruntime.Message{{Role: zeroruntime.MessageRoleAssistant, ToolCalls: []zeroruntime.ToolCall{{Name: planToolName, Arguments: arguments}}}}
+	if parity := state.observePlanParity(messages); parity != taskPlanParityMatch {
+		t.Fatalf("normalized state should still match its transcript event, got %q", parity)
+	}
+
+	empty := newTaskState("objective", nil)
+	empty.observe(taskStateEvent{kind: taskStateEventPlan, arguments: `{"plan":[]}`})
+	emptyMessages := []zeroruntime.Message{{Role: zeroruntime.MessageRoleAssistant, ToolCalls: []zeroruntime.ToolCall{{Name: planToolName, Arguments: `{"plan":[]}`}}}}
+	if parity := empty.observePlanParity(emptyMessages); parity != taskPlanParityMatch {
+		t.Fatalf("explicit empty plan should match transcript, got %q", parity)
+	}
+}
+
+func TestTaskStateContextFallsBackWhenTranscriptDiffers(t *testing.T) {
+	state := newTaskState("objective", nil)
+	state.observe(taskStateEvent{kind: taskStateEventPlan, arguments: `{"plan":[{"content":"tracked","status":"completed"}]}`})
+	messages := []zeroruntime.Message{{Role: zeroruntime.MessageRoleAssistant, ToolCalls: []zeroruntime.ToolCall{
+		{Name: planToolName, Arguments: `{"plan":[{"content":"transcript","status":"pending"}]}`},
+	}}}
+
+	context := state.completionContext(messages, true)
+	if !context.PlanPending || context.PlanMatchesTranscript {
+		t.Fatalf("completion context must retain transcript truth on mismatch: %#v", context)
+	}
+	if context.Objective != "objective" {
+		t.Fatalf("objective lost from completion context: %#v", context)
+	}
+}
+
+func TestTaskStateCompactionSnapshotRetainsObjectiveOnPlanMismatch(t *testing.T) {
+	state := newTaskState("objective", nil)
+	state.observe(taskStateEvent{kind: taskStateEventPlan, arguments: `{"plan":[{"content":"verify","status":"pending"}]}`})
+	matching := []zeroruntime.Message{{Role: zeroruntime.MessageRoleAssistant, ToolCalls: []zeroruntime.ToolCall{
+		{Name: planToolName, Arguments: `{"plan":[{"content":"verify","status":"pending"}]}`},
+	}}}
+	if snapshot := state.snapshotForCompaction(matching); snapshot == nil || snapshot.Objective != "objective" {
+		t.Fatalf("matching transcript should produce compact state, got %#v", snapshot)
+	}
+
+	mismatching := append([]zeroruntime.Message(nil), matching...)
+	mismatching[0].ToolCalls = []zeroruntime.ToolCall{{Name: planToolName, Arguments: `{"plan":[{"content":"other","status":"pending"}]}`}}
+	if snapshot := state.snapshotForCompaction(mismatching); snapshot == nil || snapshot.Objective != "objective" || snapshot.PlanParity != taskPlanParityMismatch {
+		t.Fatalf("plan mismatch must retain immutable objective and mark mutable state uncorroborated, got %#v", snapshot)
+	}
+}
+
+func TestParseTaskPlanRejectsArgumentsTheToolWouldReject(t *testing.T) {
+	for _, arguments := range []string{
+		`{}`,
+		`{"plan":null}`,
+		`{"plan":[{"step":"alias is not accepted"}]}`,
+		`{"plan":[{"content":""}]}`,
+		`{"plan":[{"content":"valid"},{"content":""}]}`,
+		`{"plan":[{"id":4,"content":"valid"}]}`,
+	} {
+		if plan, ok := parseTaskPlan(arguments); ok {
+			t.Fatalf("parseTaskPlan(%s) = %#v, true; want rejected", arguments, plan)
+		}
+	}
+}

internal/agent/turn_session.go

@@ -0,0 +1,21 @@
+package agent
+
+import (
+	"context"
+
+	"github.com/Gitlawb/zero/internal/zeroruntime"
+)
+
+// sessionProvider adapts a TurnSession back to the Provider interface so the
+// loop's existing Provider-shaped call sites (streamWithReconnect, the
+// compaction summarizer, finalAnswerAfterMaxTurns) route their stream I/O
+// through the session without any signature change. For the default adapter
+// this reduces to the wrapped provider's StreamCompletion, so behavior is
+// byte-identical; an optimized session (PR8) takes effect here transparently.
+type sessionProvider struct {
+	session zeroruntime.TurnSession
+}
+
+func (s sessionProvider) StreamCompletion(ctx context.Context, request zeroruntime.CompletionRequest) (<-chan zeroruntime.StreamEvent, error) {
+	return s.session.Stream(ctx, request)
+}

internal/agent/turn_session_test.go

@@ -0,0 +1,367 @@
+package agent
+
+import (
+	"context"
+	"errors"
+	"strings"
+	"testing"
+
+	"github.com/Gitlawb/zero/internal/tools"
+	"github.com/Gitlawb/zero/internal/zeroruntime"
+)
+
+// fakeTurnSession wraps an inner provider for streaming while counting the
+// session lifecycle, so tests can observe exactly how the loop drives it.
+type fakeTurnSession struct {
+	inner    Provider
+	prewarms int
+	streams  int
+	closes   int
+	closeErr error
+}
+
+func (s *fakeTurnSession) Prewarm(context.Context) error { s.prewarms++; return nil }
+
+func (s *fakeTurnSession) Stream(ctx context.Context, request zeroruntime.CompletionRequest) (<-chan zeroruntime.StreamEvent, error) {
+	s.streams++
+	return s.inner.StreamCompletion(ctx, request)
+}
+
+func (s *fakeTurnSession) Compact(context.Context, zeroruntime.CompletionRequest) ([]zeroruntime.Message, error) {
+	return nil, zeroruntime.ErrCompactionUnsupported
+}
+
+func (s *fakeTurnSession) Close() error { s.closes++; return s.closeErr }
+
+// fakeTurnSessionProvider opens a scripted session (or fails to).
+type fakeTurnSessionProvider struct {
+	session *fakeTurnSession
+	openErr error
+	opens   int
+}
+
+func (p *fakeTurnSessionProvider) OpenTurnSession(context.Context) (zeroruntime.TurnSession, error) {
+	p.opens++
+	if p.openErr != nil {
+		return nil, p.openErr
+	}
+	return p.session, nil
+}
+
+func (p *fakeTurnSessionProvider) Capabilities() zeroruntime.ProviderCapabilities {
+	return zeroruntime.ProviderCapabilities{}
+}
+
+func singleAnswerTurns(answer string) [][]zeroruntime.StreamEvent {
+	return [][]zeroruntime.StreamEvent{{
+		{Type: zeroruntime.StreamEventText, Content: answer},
+		{Type: zeroruntime.StreamEventDone},
+	}}
+}
+
+// TestRunOpenTurnSessionFailureSurfaces verifies a failed session open is a
+// clean run-start error: no panic, no stream ever issued, nothing to close.
+func TestRunOpenTurnSessionFailureSurfaces(t *testing.T) {
+	positional := &mockProvider{turns: singleAnswerTurns("never reached")}
+	tsp := &fakeTurnSessionProvider{openErr: errors.New("handshake refused")}
+
+	_, err := Run(context.Background(), "go", positional, Options{
+		MaxTurns:            2,
+		TurnSessionProvider: tsp,
+	})
+	if err == nil {
+		t.Fatal("expected an error from a failed session open")
+	}
+	if !strings.Contains(err.Error(), "open turn session") || !strings.Contains(err.Error(), "handshake refused") {
+		t.Fatalf("expected a wrapped open-turn-session error, got %v", err)
+	}
+	if len(positional.requests) != 0 {
+		t.Fatalf("expected no provider request after a failed open, got %d", len(positional.requests))
+	}
+	if tsp.opens != 1 {
+		t.Fatalf("expected exactly one open attempt, got %d", tsp.opens)
+	}
+}
+
+// TestRunCloseFailureIsSafe verifies a Close error at teardown is swallowed:
+// the run still returns its normal result.
+func TestRunCloseFailureIsSafe(t *testing.T) {
+	inner := &mockProvider{turns: singleAnswerTurns("done")}
+	session := &fakeTurnSession{inner: inner, closeErr: errors.New("close blew up")}
+	tsp := &fakeTurnSessionProvider{session: session}
+
+	result, err := Run(context.Background(), "go", inner, Options{
+		MaxTurns:            2,
+		TurnSessionProvider: tsp,
+	})
+	if err != nil {
+		t.Fatalf("expected Close failure to be swallowed, got %v", err)
+	}
+	if result.FinalAnswer != "done" {
+		t.Fatalf("expected normal result despite Close error, got %q", result.FinalAnswer)
+	}
+	if session.closes != 1 {
+		t.Fatalf("expected exactly one Close at teardown, got %d", session.closes)
+	}
+}
+
+// TestRunStreamsThroughTurnSession verifies that when a TurnSessionProvider is
+// wired, every model request of the run flows through the session (and the
+// session is prewarmed once and closed once).
+func TestRunStreamsThroughTurnSession(t *testing.T) {
+	inner := &mockProvider{turns: singleAnswerTurns("via session")}
+	session := &fakeTurnSession{inner: inner}
+	tsp := &fakeTurnSessionProvider{session: session}
+
+	// The positional provider is a DIFFERENT mock: it must stay untouched,
+	// proving the session (not the positional provider) carried the run.
+	positional := &mockProvider{turns: singleAnswerTurns("wrong path")}
+
+	result, err := Run(context.Background(), "go", positional, Options{
+		MaxTurns:            2,
+		TurnSessionProvider: tsp,
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if result.FinalAnswer != "via session" {
+		t.Fatalf("expected the session-backed answer, got %q", result.FinalAnswer)
+	}
+	if len(positional.requests) != 0 {
+		t.Fatalf("expected the positional provider to be bypassed, got %d requests", len(positional.requests))
+	}
+	if session.streams == 0 || session.streams != len(inner.requests) {
+		t.Fatalf("expected every request to flow through the session: streams=%d inner=%d", session.streams, len(inner.requests))
+	}
+	if session.prewarms != 1 {
+		t.Fatalf("expected exactly one prewarm, got %d", session.prewarms)
+	}
+	if session.closes != 1 {
+		t.Fatalf("expected exactly one close, got %d", session.closes)
+	}
+}
+
+// TestRunDefaultTurnSessionMatchesRawProvider verifies the default (nil
+// TurnSessionProvider) path is behavior-identical to passing an explicit
+// default adapter over the same provider: same result, same request count.
+func TestRunDefaultTurnSessionMatchesRawProvider(t *testing.T) {
+	run := func(explicit bool) (Result, *mockProvider) {
+		provider := &mockProvider{turns: escalateThenAnswerTurns("identical")}
+		registry := tools.NewRegistry()
+		registry.Register(escalatingTool{target: ""})
+		options := Options{Registry: registry, MaxTurns: 4}
+		if explicit {
+			options.TurnSessionProvider = zeroruntime.NewProviderTurnSessionProvider(provider, zeroruntime.ProviderCapabilities{})
+		}
+		result, err := Run(context.Background(), "go", provider, options)
+		if err != nil {
+			t.Fatal(err)
+		}
+		return result, provider
+	}
+
+	defaultResult, defaultProvider := run(false)
+	explicitResult, explicitProvider := run(true)
+
+	if defaultResult.FinalAnswer != explicitResult.FinalAnswer {
+		t.Fatalf("final answers diverged: default=%q explicit=%q", defaultResult.FinalAnswer, explicitResult.FinalAnswer)
+	}
+	if defaultResult.Turns != explicitResult.Turns {
+		t.Fatalf("turn counts diverged: default=%d explicit=%d", defaultResult.Turns, explicitResult.Turns)
+	}
+	if len(defaultProvider.requests) != len(explicitProvider.requests) {
+		t.Fatalf("request counts diverged: default=%d explicit=%d", len(defaultProvider.requests), len(explicitProvider.requests))
+	}
+}
+
+// TestRunModelSwitchClosesSessionAndContinues verifies a mid-run model switch
+// closes the active session exactly once and streams the rest of the run on
+// the new provider.
+func TestRunModelSwitchClosesSessionAndContinues(t *testing.T) {
+	registry := tools.NewRegistry()
+	registry.Register(escalatingTool{target: "claude-opus-4.1"})
+
+	firstInner := &mockProvider{turns: escalateThenAnswerTurns("unused")}
+	firstSession := &fakeTurnSession{inner: firstInner}
+	tsp := &fakeTurnSessionProvider{session: firstSession}
+
+	secondProvider := &mockProvider{turns: singleAnswerTurns("answered after switch")}
+
+	result, err := Run(context.Background(), "go", firstInner, Options{
+		Registry:            registry,
+		Model:               "claude-sonnet-4.5",
+		MaxTurns:            4,
+		TurnSessionProvider: tsp,
+		ModelSwitcher: func(_ context.Context, _ string) (Provider, error) {
+			return secondProvider, nil
+		},
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if result.FinalAnswer != "answered after switch" {
+		t.Fatalf("expected the post-switch answer, got %q", result.FinalAnswer)
+	}
+	// The original session handled exactly the escalation turn, then was closed
+	// once by the swap (the teardown defer closes the NEW session, not this one).
+	if firstSession.streams != 1 {
+		t.Fatalf("expected the original session to stream exactly the escalation turn, got %d", firstSession.streams)
+	}
+	if firstSession.closes != 1 {
+		t.Fatalf("expected the swap to close the original session exactly once, got %d", firstSession.closes)
+	}
+	if len(secondProvider.requests) != 1 {
+		t.Fatalf("expected the post-switch turn on the new provider, got %d requests", len(secondProvider.requests))
+	}
+}
+
+// TestRunModelSessionSwitcherCarriesOptimizedSession verifies the target-aware
+// switcher: the switched-to TurnSessionProvider's DISTINCT session receives the
+// post-switch streams, is prewarmed exactly once, and is closed exactly once at
+// teardown — and the legacy ModelSwitcher is never consulted when both are set.
+func TestRunModelSessionSwitcherCarriesOptimizedSession(t *testing.T) {
+	registry := tools.NewRegistry()
+	registry.Register(escalatingTool{target: "claude-opus-4.1"})
+
+	firstInner := &mockProvider{turns: escalateThenAnswerTurns("unused")}
+	firstSession := &fakeTurnSession{inner: firstInner}
+	initial := &fakeTurnSessionProvider{session: firstSession}
+
+	switchedInner := &mockProvider{turns: singleAnswerTurns("answered on the switched session")}
+	switchedSession := &fakeTurnSession{inner: switchedInner}
+	switched := &fakeTurnSessionProvider{session: switchedSession}
+
+	var switchedTo string
+	legacyCalled := false
+	result, err := Run(context.Background(), "go", firstInner, Options{
+		Registry:            registry,
+		Model:               "claude-sonnet-4.5",
+		MaxTurns:            4,
+		TurnSessionProvider: initial,
+		ModelSessionSwitcher: func(_ context.Context, modelID string) (zeroruntime.TurnSessionProvider, error) {
+			switchedTo = modelID
+			return switched, nil
+		},
+		ModelSwitcher: func(_ context.Context, _ string) (Provider, error) {
+			legacyCalled = true
+			return nil, errors.New("legacy switcher must not be consulted")
+		},
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if result.FinalAnswer != "answered on the switched session" {
+		t.Fatalf("expected the switched session's answer, got %q", result.FinalAnswer)
+	}
+	if switchedTo != "claude-opus-4.1" {
+		t.Fatalf("expected switch to claude-opus-4.1, got %q", switchedTo)
+	}
+	if legacyCalled {
+		t.Fatal("legacy ModelSwitcher was consulted despite ModelSessionSwitcher being set")
+	}
+	if switched.opens != 1 {
+		t.Fatalf("expected exactly one open of the switched provider, got %d", switched.opens)
+	}
+	// The switched session carries the rest of the run: it streams the answer
+	// turn, is prewarmed exactly once at the swap, and is closed exactly once by
+	// the teardown defer.
+	if switchedSession.streams != 1 || len(switchedInner.requests) != 1 {
+		t.Fatalf("expected the switched session to stream the post-switch turn, streams=%d inner=%d", switchedSession.streams, len(switchedInner.requests))
+	}
+	if switchedSession.prewarms != 1 {
+		t.Fatalf("expected the switched session to be prewarmed exactly once, got %d", switchedSession.prewarms)
+	}
+	if switchedSession.closes != 1 {
+		t.Fatalf("expected the switched session to be closed exactly once at teardown, got %d", switchedSession.closes)
+	}
+	// The original session ends with the swap: one stream, one close.
+	if firstSession.streams != 1 || firstSession.closes != 1 {
+		t.Fatalf("expected the original session to end at the swap (streams=%d closes=%d)", firstSession.streams, firstSession.closes)
+	}
+}
+
+// TestRunModelSessionSwitcherOpenFailureIsNonFatal verifies the swap-time open
+// failure: the switcher returns a TurnSessionProvider whose OpenTurnSession
+// fails. The run stays non-fatal on the ORIGINAL session (closed only at
+// teardown), and the switch-failure note reaches the next request.
+func TestRunModelSessionSwitcherOpenFailureIsNonFatal(t *testing.T) {
+	registry := tools.NewRegistry()
+	registry.Register(escalatingTool{target: "claude-opus-4.1"})
+
+	inner := &mockProvider{turns: escalateThenAnswerTurns("recovered after failed open")}
+	session := &fakeTurnSession{inner: inner}
+	failingOpen := &fakeTurnSessionProvider{openErr: errors.New("switched handshake refused")}
+
+	result, err := Run(context.Background(), "go", inner, Options{
+		Registry:            registry,
+		Model:               "claude-sonnet-4.5",
+		MaxTurns:            4,
+		TurnSessionProvider: &fakeTurnSessionProvider{session: session},
+		ModelSessionSwitcher: func(_ context.Context, _ string) (zeroruntime.TurnSessionProvider, error) {
+			return failingOpen, nil
+		},
+	})
+	if err != nil {
+		t.Fatalf("expected a failed swap open to be non-fatal, got %v", err)
+	}
+	if result.FinalAnswer != "recovered after failed open" {
+		t.Fatalf("expected the run to recover on the original session, got %q", result.FinalAnswer)
+	}
+	if failingOpen.opens != 1 {
+		t.Fatalf("expected exactly one open attempt on the switched provider, got %d", failingOpen.opens)
+	}
+	// The original session serves both turns and is closed only at teardown —
+	// never by the failed swap.
+	if session.streams != 2 || session.closes != 1 {
+		t.Fatalf("expected the original session to serve both turns and close once (streams=%d closes=%d)", session.streams, session.closes)
+	}
+	var sawNote bool
+	for _, message := range inner.requests[1].Messages {
+		if message.Role == zeroruntime.MessageRoleUser && strings.Contains(strings.ToLower(message.Content), "could not switch") {
+			sawNote = true
+		}
+	}
+	if !sawNote {
+		t.Fatalf("expected a switch-failure note on the next turn, messages: %+v", inner.requests[1].Messages)
+	}
+}
+
+// TestRunModelSessionSwitcherErrorIsNonFatal verifies a ModelSessionSwitcher
+// error keeps the run on the current session with a transcript note — the same
+// non-fatal contract as ModelSwitcher.
+func TestRunModelSessionSwitcherErrorIsNonFatal(t *testing.T) {
+	registry := tools.NewRegistry()
+	registry.Register(escalatingTool{target: "claude-opus-4.1"})
+
+	inner := &mockProvider{turns: escalateThenAnswerTurns("recovered on original session")}
+	session := &fakeTurnSession{inner: inner}
+
+	result, err := Run(context.Background(), "go", inner, Options{
+		Registry:            registry,
+		Model:               "claude-sonnet-4.5",
+		MaxTurns:            4,
+		TurnSessionProvider: &fakeTurnSessionProvider{session: session},
+		ModelSessionSwitcher: func(_ context.Context, _ string) (zeroruntime.TurnSessionProvider, error) {
+			return nil, errors.New("session build blew up")
+		},
+	})
+	if err != nil {
+		t.Fatalf("expected session-switcher error to be non-fatal, got %v", err)
+	}
+	if result.FinalAnswer != "recovered on original session" {
+		t.Fatalf("expected the run to recover on the original session, got %q", result.FinalAnswer)
+	}
+	// Both turns stream through the original session; it closes once at teardown.
+	if session.streams != 2 || session.closes != 1 {
+		t.Fatalf("expected the original session to serve both turns and close once (streams=%d closes=%d)", session.streams, session.closes)
+	}
+	var sawNote bool
+	for _, request := range inner.requests[1].Messages {
+		if request.Role == zeroruntime.MessageRoleUser && strings.Contains(strings.ToLower(request.Content), "could not switch") {
+			sawNote = true
+		}
+	}
+	if !sawNote {
+		t.Fatalf("expected a non-fatal switch-failure note on the next turn, messages: %+v", inner.requests[1].Messages)
+	}
+}

internal/agent/types.go

@@ -7,6 +7,7 @@ import (
 	"github.com/Gitlawb/zero/internal/sandbox"
 	"github.com/Gitlawb/zero/internal/streamjson"
 	"github.com/Gitlawb/zero/internal/tools"
+	"github.com/Gitlawb/zero/internal/trace"
 	"github.com/Gitlawb/zero/internal/zeroruntime"
 )
 
@@ -60,10 +61,13 @@ const (
 )
 
 type ToolResult struct {
-	ToolCallID   string
-	Name         string
-	Status       tools.Status
-	Output       string
+	ToolCallID string
+	Name       string
+	Status     tools.Status
+	Output     string
+	// Truncated reports that the tool's model-visible output omitted content.
+	// The full result may be recoverable through Meta["spill_path"].
+	Truncated    bool
 	Meta         map[string]string
 	Redacted     bool
 	ChangedFiles []string
@@ -71,6 +75,12 @@ type ToolResult struct {
 	// DenialReason categorizes why a tool call was blocked (empty when it ran).
 	// It lets a surface distinguish the cause precisely instead of parsing Output.
 	DenialReason DenialCategory
+	// Risk is the sandbox risk classification of this call, stamped for EXECUTED
+	// results so run-policy observers (the execution-profile controller) can see
+	// the risk level of an allowed mutation. It mirrors the classification the
+	// permission path already computes; denied or canceled results keep the zero
+	// value. Pure observation: nothing about permissions or sandboxing changes.
+	Risk sandbox.Risk
 	// LoadedTools carries the deferred-tool names a tool_search call asked the
 	// loop to expose next turn (lifted from Meta["load_tools"]). nil for every
 	// ordinary tool result; only tool_search populates it.
@@ -94,6 +104,54 @@ const (
 	DenialHookBlocked      DenialCategory = "hook_blocked"      // vetoed by a beforeTool hook
 )
 
+// ProfilePolicy is the loop-facing slice of a selected execution profile.
+// The surface (exec flag, TUI command) resolves a named profile into this
+// policy; the loop only ever sees the policy, never the catalog.
+type ProfilePolicy struct {
+	// Name labels trace counters and diagnostics (e.g. "fast"). The trace
+	// recorder's profile label is set by the caller at recorder construction.
+	Name string
+	// Escalate, when non-nil, arms one-shot in-run posture escalation.
+	Escalate *PostureEscalation
+}
+
+// PostureEscalation describes a one-shot escalation to stricter knob values,
+// applied mid-run when an armed trigger fires. Targets are the values the
+// selected profile DISPLACED at run start (i.e. "restore the balanced
+// posture"), so escalation can never introduce a value that was not already
+// valid for this run and model. Zero-valued targets leave that knob untouched.
+type PostureEscalation struct {
+	// MaxTurns raises the turn ceiling to this value when greater than the
+	// ceiling in effect. 0 leaves the ceiling untouched.
+	MaxTurns int
+	// ReasoningEffort replaces the run's effort when non-empty.
+	ReasoningEffort string
+	// RestoreDefaultEffort clears the run's effort override (back to the
+	// provider/model default) when true. It exists because the displaced value
+	// of a profile-filled effort is "" — which as a ReasoningEffort target
+	// means "leave untouched" — so restoring the default needs its own signal.
+	// Ignored when ReasoningEffort is non-empty.
+	RestoreDefaultEffort bool
+	// RestoreCompletionGate re-enables RequireCompletionSignal (headless
+	// completion semantics) when true.
+	RestoreCompletionGate bool
+
+	// Triggers. A zero value disables that signal entirely.
+	// OnToolFailureStreak fires when the repeated-failure guard observes a
+	// same-tool retriable-failure streak of at least this length.
+	OnToolFailureStreak int
+	// OnCompletionUncertain fires on the Nth uncertain completion evaluation
+	// (continue nudge or semantic check). Headless only: the completion gate
+	// never runs interactively.
+	OnCompletionUncertain int
+	// OnSelfCorrectFailure fires when a post-edit verification cycle reports a
+	// failing outcome (correcting, reported, or aborted).
+	OnSelfCorrectFailure bool
+	// OnRiskyMutation fires when an EXECUTED tool result carries a sandbox risk
+	// level at or above this threshold. Empty disables the signal.
+	OnRiskyMutation sandbox.RiskLevel
+}
+
 type PermissionRequest struct {
 	ToolCallID         string                     `json:"toolCallId"`
 	ToolName           string                     `json:"name"`
@@ -279,6 +337,37 @@ type Options struct {
 	// request), so every existing caller is unaffected. A returned error is
 	// non-fatal: the run continues on the current model.
 	ModelSwitcher func(ctx context.Context, modelID string) (Provider, error)
+	// TurnSessionProvider, when set, supplies the turn session the run streams
+	// through — the seam an optimized provider session (connection reuse,
+	// prewarm, native compaction) plugs into without touching the loop. nil
+	// keeps the default: the loop wraps the passed provider in a no-op session
+	// whose Stream IS provider.StreamCompletion, so behavior is byte-identical
+	// and every existing caller is unaffected.
+	TurnSessionProvider zeroruntime.TurnSessionProvider
+	// ModelSessionSwitcher, when set, is the target-aware escalation hook: the
+	// loop prefers it over ModelSwitcher, and its TurnSessionProvider keeps an
+	// optimized session (and its capabilities) across a mid-run model switch.
+	// nil falls back to ModelSwitcher, whose bare Provider is wrapped in the
+	// default no-op session — today's behavior, unchanged. Same non-fatal error
+	// contract as ModelSwitcher: a returned error records a note and the run
+	// continues on the current model and session.
+	ModelSessionSwitcher func(ctx context.Context, modelID string) (zeroruntime.TurnSessionProvider, error)
+	// Profile, when set, arms the execution-profile posture controller for this
+	// run (auto-escalation to stricter knob values on failure/uncertainty/risky
+	// mutation signals). nil — the default everywhere today — leaves the loop
+	// byte-identical: no observation, no escalation, no counters. Same opt-in
+	// convention as Trace and SelfCorrect.
+	Profile *ProfilePolicy
+	// Trace, when set, records per-turn timing for the run: the loop stamps
+	// spans (prompt build, generation, tool execution, permission wait,
+	// compaction, provider connect) and counters (model requests, tool calls,
+	// retries, tokens) into it. nil DISABLES tracing entirely — every stamp is
+	// nil-safe and the loop is byte-identical to an untraced run. The caller
+	// owns the recorder: Run stamps into it but does not Finish or emit it.
+	// A fresh Recorder is required per Run — reusing one across runs merges
+	// their spans, counters, and first-event timestamps, and Finish freezes a
+	// recorder so no further stamps take.
+	Trace *trace.Recorder
 	// SelfCorrect, when set, runs a post-edit verify-and-correct cycle after a
 	// mutating tool call: it verifies the changed files (LSP diagnostics + project
 	// tests) and feeds failures back to the model to fix, bounded by an attempt
@@ -301,8 +390,11 @@ type Options struct {
 	// continuation cue ("…Let me check the config:"). The loop then nudges the
 	// model to continue instead, bounded by maxContinueNudges (and still by
 	// MaxTurns and the run deadline); if the model keeps stalling, the run
-	// finalizes as INCOMPLETE (Result.Incomplete) rather than success. Default
-	// false leaves the loop byte-identical, so the interactive TUI is unaffected.
+	// finalizes as INCOMPLETE (Result.Incomplete) rather than success. When the
+	// run's profile also enables SelfCorrect, an otherwise-complete turn gets one
+	// task-grounded semantic check before success; profiles without SelfCorrect
+	// add no model call. Default false leaves the loop byte-identical, so the
+	// interactive TUI is unaffected.
 	RequireCompletionSignal bool
 
 	runPermissions *permissionRunState

internal/aimlapi/client.go

@@ -0,0 +1,259 @@
+package aimlapi
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"strings"
+	"time"
+)
+
+// PaymentMethod selects how a partner-checkout top-up is paid for.
+type PaymentMethod string
+
+const (
+	PaymentMethodCard   PaymentMethod = "card"
+	PaymentMethodCrypto PaymentMethod = "crypto"
+)
+
+// SessionStatus is the lifecycle state of a partner-checkout session, as reported
+// by the aimlapi.com backend while polling for payment.
+type SessionStatus string
+
+const (
+	SessionStatusPendingAuth    SessionStatus = "pending_auth"
+	SessionStatusPendingPayment SessionStatus = "pending_payment"
+	SessionStatusPaid           SessionStatus = "paid"
+	SessionStatusExchanging     SessionStatus = "exchanging"
+	SessionStatusExchanged      SessionStatus = "exchanged"
+	SessionStatusCancelled      SessionStatus = "cancelled"
+	SessionStatusExpired        SessionStatus = "expired"
+	SessionStatusFailed         SessionStatus = "failed"
+)
+
+// AuthResult is the bearer token minted by a passwordless sign-in / sign-up.
+type AuthResult struct {
+	Token string `json:"token"`
+	Exp   int64  `json:"exp"`
+}
+
+// PartnerCheckoutSession is a partner-attributed top-up session; its SessionToken
+// addresses it on later pay/exchange/poll calls.
+type PartnerCheckoutSession struct {
+	ID             string        `json:"id"`
+	SessionToken   string        `json:"sessionToken"`
+	PartnerID      string        `json:"partnerId"`
+	PartnerName    *string       `json:"partnerName"`
+	UserID         *int64        `json:"userId"`
+	AmountUSDMinor *int64        `json:"amountUsdMinor"`
+	Status         SessionStatus `json:"status"`
+	IssuedKeyID    *string       `json:"issuedKeyId"`
+	ReturnURL      *string       `json:"returnUrl"`
+}
+
+// PaymentSession is the hosted payment-provider checkout; PayURL is the page the
+// user opens to pay.
+type PaymentSession struct {
+	ProviderSessionID string `json:"providerSessionId"`
+	PayURL            string `json:"payUrl"`
+}
+
+// PayResult pairs the hosted checkout with the updated partner-checkout session
+// returned when a top-up payment is initiated.
+type PayResult struct {
+	Checkout        PaymentSession         `json:"checkout"`
+	PartnerCheckout PartnerCheckoutSession `json:"partnerCheckout"`
+}
+
+// ExchangeResult holds the API key minted when a paid session is exchanged.
+type ExchangeResult struct {
+	APIKey   string `json:"apiKey"`
+	APIKeyID string `json:"apiKeyId"`
+}
+
+// TopUpByKeyRequest funds a partner-checkout session with the API key that owns
+// the account (Path A / env key), instead of an email session.
+type TopUpByKeyRequest struct {
+	SessionToken     string
+	AmountUSDMinor   int
+	PaymentSessionID string // idempotency: same id → same checkout, never a second charge
+	AutoTopUp        bool   // enroll the account in automatic top-up at checkout (card, saved off-session)
+	SuccessURL       string
+	CancelURL        string
+}
+
+// TopUpByKeyResult is the hosted checkout returned by TopUpByKey.
+type TopUpByKeyResult struct {
+	Checkout PaymentSession `json:"checkout"`
+}
+
+// APIError is a non-2xx HTTP response from the aimlapi.com API. Status carries the
+// code so callers can branch (e.g. 401 = bad key, 5xx = retryable).
+type APIError struct {
+	Message string
+	Status  int
+	Body    string
+}
+
+// Error renders the method, endpoint, status, and (when present) the response body.
+func (e APIError) Error() string {
+	if strings.TrimSpace(e.Body) != "" {
+		return fmt.Sprintf("%s: HTTP %d: %s", e.Message, e.Status, strings.TrimSpace(e.Body))
+	}
+	return fmt.Sprintf("%s: HTTP %d", e.Message, e.Status)
+}
+
+// Client talks to the aimlapi.com auth, app, and inference APIs for the onboarding
+// and partner-checkout top-up flows.
+type Client struct {
+	endpoints  Endpoints
+	httpClient *http.Client
+}
+
+func NewClient(endpoints Endpoints, httpClient *http.Client) *Client {
+	if httpClient == nil {
+		httpClient = &http.Client{Timeout: 60 * time.Second}
+	}
+	return &Client{endpoints: endpoints, httpClient: httpClient}
+}
+
+// CreateSession opens a partner-checkout session attributed to partnerID; the
+// returned SessionToken addresses it on the pay/exchange/poll calls.
+func (c *Client) CreateSession(ctx context.Context, partnerID string, partnerName string, returnURL string) (PartnerCheckoutSession, error) {
+	body := map[string]any{"partnerId": partnerID}
+	if strings.TrimSpace(partnerName) != "" {
+		body["partnerName"] = strings.TrimSpace(partnerName)
+	}
+	if strings.TrimSpace(returnURL) != "" {
+		body["returnUrl"] = strings.TrimSpace(returnURL)
+	}
+	var result PartnerCheckoutSession
+	err := c.request(ctx, http.MethodPost, strings.TrimRight(c.endpoints.AppBaseURL, "/")+"/v3/partner-checkout/sessions", "", body, &result)
+	return result, err
+}
+
+// GetSession fetches the current state of a partner-checkout session; used to poll
+// for payment completion.
+func (c *Client) GetSession(ctx context.Context, sessionToken string) (PartnerCheckoutSession, error) {
+	var result PartnerCheckoutSession
+	err := c.request(ctx, http.MethodGet, strings.TrimRight(c.endpoints.AppBaseURL, "/")+"/v3/partner-checkout/sessions/"+urlPathEscape(sessionToken), "", nil, &result)
+	return result, err
+}
+
+// Pay initiates payment for a session and returns the hosted checkout URL.
+// autoTopUp enrolls the account in automatic top-up at checkout time.
+func (c *Client) Pay(ctx context.Context, bearer string, sessionToken string, amountUSDMinor int, paymentSessionID string, method PaymentMethod, successURL string, cancelURL string, autoTopUp bool) (PayResult, error) {
+	body := map[string]any{
+		"amountUsdMinor":   amountUSDMinor,
+		"paymentSessionId": paymentSessionID,
+		"method":           method,
+	}
+	if strings.TrimSpace(successURL) != "" {
+		body["successUrl"] = strings.TrimSpace(successURL)
+	}
+	if strings.TrimSpace(cancelURL) != "" {
+		body["cancelUrl"] = strings.TrimSpace(cancelURL)
+	}
+	// Only sent when enabled: enrolls the account in automatic top-up. The backend
+	// honours this field at checkout time.
+	if autoTopUp {
+		body["autoTopUp"] = true
+	}
+	var result PayResult
+	err := c.request(ctx, http.MethodPost, strings.TrimRight(c.endpoints.AppBaseURL, "/")+"/v3/partner-checkout/sessions/"+urlPathEscape(sessionToken)+"/pay", bearer, body, &result)
+	return result, err
+}
+
+// Exchange converts a paid session into a freshly minted API key (new-account flow).
+func (c *Client) Exchange(ctx context.Context, bearer string, sessionToken string) (ExchangeResult, error) {
+	var result ExchangeResult
+	err := c.request(ctx, http.MethodPost, strings.TrimRight(c.endpoints.AppBaseURL, "/")+"/v3/partner-checkout/sessions/"+urlPathEscape(sessionToken)+"/exchange", bearer, nil, &result)
+	return result, err
+}
+
+// TopUpByKey funds a partner-checkout session using the raw API key that owns the
+// account (Path A / env key), returning the hosted checkout. It binds the session
+// to the key's account server-side, so no email session is needed and no key is
+// exchanged. req.PaymentSessionID makes a retry idempotent (same id → same
+// checkout, never a second charge).
+func (c *Client) TopUpByKey(ctx context.Context, apiKey string, req TopUpByKeyRequest) (TopUpByKeyResult, error) {
+	body := map[string]any{
+		"sessionToken":     req.SessionToken,
+		"amountUsdMinor":   req.AmountUSDMinor,
+		"paymentSessionId": req.PaymentSessionID,
+	}
+	if req.AutoTopUp {
+		body["autoTopUp"] = true
+	}
+	if strings.TrimSpace(req.SuccessURL) != "" {
+		body["successUrl"] = strings.TrimSpace(req.SuccessURL)
+	}
+	if strings.TrimSpace(req.CancelURL) != "" {
+		body["cancelUrl"] = strings.TrimSpace(req.CancelURL)
+	}
+	var result TopUpByKeyResult
+	err := c.request(ctx, http.MethodPost, c.billingV2URL("/billing/topup"), apiKey, body, &result)
+	return result, err
+}
+
+// billingV2URL builds a v2 billing API URL from the inference base. The top-up
+// endpoint lives next to the balance endpoint on the API gateway, one version up
+// (".../v1" → ".../v2/billing/..."), so it re-anchors the version while keeping any
+// host/prefix an override supplied.
+func (c *Client) billingV2URL(path string) string {
+	base := strings.TrimRight(strings.TrimSpace(c.endpoints.InferenceBaseURL), "/")
+	base = strings.TrimSuffix(base, "/v1")
+	return strings.TrimRight(base, "/") + "/v2" + path
+}
+
+func (c *Client) request(ctx context.Context, method string, endpoint string, bearer string, body any, out any) error {
+	var reader io.Reader
+	if body != nil {
+		data, err := json.Marshal(body)
+		if err != nil {
+			return err
+		}
+		reader = bytes.NewReader(data)
+	}
+	request, err := http.NewRequestWithContext(ctx, method, endpoint, reader)
+	if err != nil {
+		return err
+	}
+	request.Header.Set("Accept", "application/json")
+	if body != nil {
+		request.Header.Set("Content-Type", "application/json")
+	}
+	if strings.TrimSpace(bearer) != "" {
+		request.Header.Set("Authorization", "Bearer "+strings.TrimSpace(bearer))
+	}
+	response, err := c.httpClient.Do(request)
+	if err != nil {
+		return fmt.Errorf("network request to %s failed: %w", endpoint, err)
+	}
+	defer response.Body.Close()
+	text, readErr := io.ReadAll(io.LimitReader(response.Body, 1<<20))
+	if readErr != nil {
+		return readErr
+	}
+	if response.StatusCode < 200 || response.StatusCode >= 300 {
+		return APIError{Message: method + " " + endpoint, Status: response.StatusCode, Body: string(text)}
+	}
+	if out == nil {
+		return nil
+	}
+	if len(bytes.TrimSpace(text)) == 0 {
+		return APIError{Message: method + " " + endpoint + " returned empty body", Status: response.StatusCode}
+	}
+	if err := json.Unmarshal(text, out); err != nil {
+		return APIError{Message: method + " " + endpoint + " returned non-JSON body", Status: response.StatusCode, Body: string(text)}
+	}
+	return nil
+}
+
+func urlPathEscape(value string) string {
+	return url.PathEscape(value)
+}

internal/aimlapi/client_onboard.go

@@ -0,0 +1,106 @@
+package aimlapi
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+	"strings"
+)
+
+// Additional client methods backing the interactive TUI onboarding flow. They
+// target the endpoints shipped in the aimlapi backend:
+//   - GET  {inference}/billing/balance            (Path A: validate key + balance)
+//   - PATCH{auth}/v1/auth/account                 (Path B: does the account exist?)
+//   - POST {auth}/v1/auth/sign-in/code(/verify)   (Path B existing: passwordless login)
+//   - POST {auth}/v1/auth/account/passwordless    (Path B new: email-only signup)
+//   - POST {app}/v1/keys                          (mint a key once we hold a session)
+
+// BalanceResult is the wallet balance returned by GetBalance, with the backend's
+// low-balance flag and threshold.
+type BalanceResult struct {
+	Balance             float64 `json:"balance"`
+	LowBalance          bool    `json:"lowBalance"`
+	LowBalanceThreshold float64 `json:"lowBalanceThreshold"`
+}
+
+// CheckResult reports whether an email already has an account, driving the
+// sign-in vs sign-up branch of the onboarding flow.
+type CheckResult struct {
+	// "sign-in" (account exists) or "sign-up" (no account yet).
+	Action   string  `json:"action"`
+	Provider *string `json:"provider"`
+}
+
+// CreatedKey is an API key minted by CreateKey.
+type CreatedKey struct {
+	Key string `json:"key"`
+	ID  string `json:"id"`
+}
+
+func (c *Client) authURL(path string) string {
+	return strings.TrimRight(c.endpoints.AuthBaseURL, "/") + path
+}
+
+func (c *Client) appURL(path string) string {
+	return strings.TrimRight(c.endpoints.AppBaseURL, "/") + path
+}
+
+func (c *Client) inferenceURL(path string) string {
+	return strings.TrimRight(c.endpoints.InferenceBaseURL, "/") + path
+}
+
+// GetBalance doubles as key validation: a 401 means the key is invalid, a 2xx
+// returns the wallet balance. Auth is the raw API key itself.
+func (c *Client) GetBalance(ctx context.Context, apiKey string) (BalanceResult, error) {
+	var result BalanceResult
+	err := c.request(ctx, http.MethodGet, c.inferenceURL("/billing/balance"), apiKey, nil, &result)
+	return result, err
+}
+
+// CheckAccount reports whether an email already has an aimlapi.com account
+// (Action "sign-in") or not ("sign-up").
+func (c *Client) CheckAccount(ctx context.Context, email string) (CheckResult, error) {
+	var result CheckResult
+	err := c.request(ctx, http.MethodPatch, c.authURL("/v1/auth/account"), "", map[string]any{"email": email}, &result)
+	return result, err
+}
+
+// SendSignInCode emails a 6-digit sign-in code to an existing account.
+func (c *Client) SendSignInCode(ctx context.Context, email string) error {
+	return c.request(ctx, http.MethodPost, c.authURL("/v1/auth/sign-in/code"), "", map[string]any{"email": email}, nil)
+}
+
+// VerifySignInCode exchanges an emailed code for a session bearer token.
+func (c *Client) VerifySignInCode(ctx context.Context, email string, code string) (AuthResult, error) {
+	var result AuthResult
+	err := c.request(ctx, http.MethodPost, c.authURL("/v1/auth/sign-in/code/verify"), "", map[string]any{"email": email, "code": code}, &result)
+	if err == nil && strings.TrimSpace(result.Token) == "" {
+		err = fmt.Errorf("aimlapi.com did not return an auth token")
+	}
+	return result, err
+}
+
+// CreatePasswordlessAccount registers a new email-only account and returns its
+// session bearer token.
+func (c *Client) CreatePasswordlessAccount(ctx context.Context, email string) (AuthResult, error) {
+	var result AuthResult
+	err := c.request(ctx, http.MethodPost, c.authURL("/v1/auth/account/passwordless"), "", map[string]any{"email": email}, &result)
+	if err == nil && strings.TrimSpace(result.Token) == "" {
+		err = fmt.Errorf("aimlapi.com did not return an auth token")
+	}
+	return result, err
+}
+
+// CreateKey mints a fresh API key for a session-holding user.
+func (c *Client) CreateKey(ctx context.Context, bearer string, name string) (CreatedKey, error) {
+	body := map[string]any{}
+	if strings.TrimSpace(name) != "" {
+		body["name"] = strings.TrimSpace(name)
+	}
+	var result CreatedKey
+	err := c.request(ctx, http.MethodPost, c.appURL("/v1/keys"), bearer, body, &result)
+	if err == nil && strings.TrimSpace(result.Key) == "" {
+		err = fmt.Errorf("aimlapi.com did not return an API key")
+	}
+	return result, err
+}

internal/aimlapi/client_test.go

@@ -0,0 +1,159 @@
+package aimlapi
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+)
+
+func TestCreateKeySendsAuthenticatedRequestAndDecodesKey(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.Method != http.MethodPost || r.URL.Path != "/v1/keys" {
+			t.Fatalf("request = %s %s, want POST /v1/keys", r.Method, r.URL.Path)
+		}
+		if got := r.Header.Get("Authorization"); got != "Bearer session-token" {
+			t.Fatalf("Authorization = %q", got)
+		}
+		var body map[string]string
+		if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
+			t.Fatal(err)
+		}
+		if body["name"] != "Zero CLI" {
+			t.Fatalf("name = %q", body["name"])
+		}
+		w.Header().Set("Content-Type", "application/json")
+		_, _ = w.Write([]byte(`{"key":"sk-issued","id":"key-id"}`))
+	}))
+	defer server.Close()
+
+	client := NewClient(Endpoints{AppBaseURL: server.URL}, server.Client())
+	key, err := client.CreateKey(context.Background(), " session-token ", " Zero CLI ")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if key.Key != "sk-issued" || key.ID != "key-id" {
+		t.Fatalf("key = %#v", key)
+	}
+}
+
+func TestCreateKeyRejectsEmptyKeyResponse(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		_, _ = w.Write([]byte(`{"id":"key-id"}`))
+	}))
+	defer server.Close()
+
+	client := NewClient(Endpoints{AppBaseURL: server.URL}, server.Client())
+	if _, err := client.CreateKey(context.Background(), "session-token", "Zero"); err == nil {
+		t.Fatal("CreateKey accepted a response without an API key")
+	}
+}
+
+func TestAuthMethodsRejectEmptyTokenResponses(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		_, _ = w.Write([]byte(`{"token":""}`))
+	}))
+	defer server.Close()
+
+	client := NewClient(Endpoints{AuthBaseURL: server.URL}, server.Client())
+	tests := []struct {
+		name string
+		call func() error
+	}{
+		{
+			name: "verify sign-in code",
+			call: func() error {
+				_, err := client.VerifySignInCode(context.Background(), "[email protected]", "123456")
+				return err
+			},
+		},
+		{
+			name: "create passwordless account",
+			call: func() error {
+				_, err := client.CreatePasswordlessAccount(context.Background(), "[email protected]")
+				return err
+			},
+		},
+	}
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			if err := test.call(); err == nil {
+				t.Fatal("accepted a response without an auth token")
+			}
+		})
+	}
+}
+
+func TestClientReturnsTypedAPIError(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		http.Error(w, "invalid key", http.StatusUnauthorized)
+	}))
+	defer server.Close()
+
+	client := NewClient(Endpoints{InferenceBaseURL: server.URL}, server.Client())
+	_, err := client.GetBalance(context.Background(), "bad-key")
+	var apiErr APIError
+	if !errors.As(err, &apiErr) {
+		t.Fatalf("error = %T %v, want APIError", err, err)
+	}
+	if apiErr.Status != http.StatusUnauthorized || apiErr.Body != "invalid key\n" {
+		t.Fatalf("APIError = %#v", apiErr)
+	}
+}
+
+func TestTypedResponseRejectsEmptySuccessBody(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		w.WriteHeader(http.StatusNoContent)
+	}))
+	defer server.Close()
+
+	client := NewClient(Endpoints{InferenceBaseURL: server.URL}, server.Client())
+	if _, err := client.GetBalance(context.Background(), "key"); err == nil {
+		t.Fatal("GetBalance accepted an empty successful response")
+	}
+}
+
+func TestBodylessOperationAcceptsEmptySuccessBody(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		w.WriteHeader(http.StatusNoContent)
+	}))
+	defer server.Close()
+
+	client := NewClient(Endpoints{AuthBaseURL: server.URL}, server.Client())
+	if err := client.SendSignInCode(context.Background(), "[email protected]"); err != nil {
+		t.Fatalf("SendSignInCode() error = %v", err)
+	}
+}
+
+func TestParseAmountUSD(t *testing.T) {
+	tests := []struct {
+		name    string
+		value   string
+		want    int
+		wantErr bool
+	}{
+		{name: "default", want: DefaultAmountUSDMinor},
+		{name: "minimum", value: "20", want: 2000},
+		{name: "cents", value: "25.49", want: 2549},
+		{name: "below minimum", value: "19.99", wantErr: true},
+		{name: "above maximum", value: "10001", wantErr: true},
+		{name: "not a number", value: "twenty", wantErr: true},
+		{name: "nan", value: "NaN", wantErr: true},
+		{name: "infinity", value: "Inf", wantErr: true},
+	}
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			got, err := ParseAmountUSD(test.value)
+			if (err != nil) != test.wantErr {
+				t.Fatalf("ParseAmountUSD(%q) error = %v", test.value, err)
+			}
+			if got != test.want {
+				t.Fatalf("ParseAmountUSD(%q) = %d, want %d", test.value, got, test.want)
+			}
+		})
+	}
+}

internal/aimlapi/config.go

@@ -0,0 +1,113 @@
+package aimlapi
+
+import (
+	"net/url"
+	"os"
+	"strings"
+)
+
+type Endpoints struct {
+	AuthBaseURL      string
+	AppBaseURL       string
+	InferenceBaseURL string
+	PayBaseURL       string
+	// VerificationBaseURL is the aimlapi web-app frontend base. The browser is sent
+	// back here after the partner checkout completes (see BuildPartnerReturnURL), so
+	// it must point at the same environment's front as the one the CLI is talking to
+	// to land the user there. Empty falls back to DefaultReturnURL.
+	VerificationBaseURL string
+}
+
+const (
+	DefaultPartnerID   = "part_62yQoGYDq4Yqnrj2R1iGrDNJ"
+	DefaultPartnerName = "Gitlawb"
+	PartnerHeaderName  = "X-AIMLAPI-Partner-ID"
+	// DefaultReturnURL is the https fallback the browser is sent to after the
+	// checkout / OAuth consent finishes when no frontend base is known. It must be
+	// a real web page the browser can open — NOT a custom scheme like
+	// zero://aimlapi/complete, which fails with "the scheme does not have a
+	// registered handler" because the CLI registers no OS protocol handler. The
+	// CLI learns of success by polling; this URL is purely the browser's landing.
+	DefaultReturnURL = "https://aimlapi.com/app"
+	DefaultModel     = "anthropic/claude-sonnet-5"
+
+	MinAmountUSDMinor     = 2000
+	MaxAmountUSDMinor     = 1000000
+	DefaultAmountUSDMinor = 2500
+)
+
+func ResolveEndpoints() Endpoints {
+	return Endpoints{
+		AuthBaseURL:         envOrDefault("AIMLAPI_AUTH_URL", "https://auth.aimlapi.com"),
+		AppBaseURL:          envOrDefault("AIMLAPI_APP_URL", "https://app.aimlapi.com"),
+		InferenceBaseURL:    envOrDefault("AIMLAPI_INFERENCE_URL", "https://api.aimlapi.com/v1"),
+		PayBaseURL:          envOrDefault("AIMLAPI_PAY_URL", "https://pay.aimlapi.com"),
+		VerificationBaseURL: envOrDefault("AIMLAPI_VERIFICATION_BASE_URL", "https://aimlapi.com/app"),
+	}
+}
+
+// ResolvePartnerID applies the same explicit-option, environment, and default
+// precedence everywhere partner attribution is used. Keeping checkout creation
+// and saved inference profiles on one resolver prevents them from attributing
+// the same user to different partners.
+func ResolvePartnerID(explicit string) string {
+	if value := strings.TrimSpace(explicit); value != "" {
+		return value
+	}
+	return envOrDefault("AIMLAPI_PARTNER_ID", DefaultPartnerID)
+}
+
+// WithResolvedPartnerHeader returns a copy with the effective partner ID set.
+// Header matching is case-insensitive so an existing spelling is replaced rather
+// than duplicated. Callers remain responsible for applying catalog attribution
+// only to the canonical AIMLAPI endpoint.
+func WithResolvedPartnerHeader(headers map[string]string) map[string]string {
+	resolved := make(map[string]string, len(headers)+1)
+	for key, value := range headers {
+		if strings.EqualFold(strings.TrimSpace(key), PartnerHeaderName) {
+			continue
+		}
+		resolved[key] = value
+	}
+	resolved[PartnerHeaderName] = ResolvePartnerID("")
+	return resolved
+}
+
+func BuildPartnerCheckoutReturnURLs(appBaseURL string, sessionToken string) (successURL string, cancelURL string) {
+	base := strings.TrimRight(strings.TrimSpace(appBaseURL), "/")
+	if base == "" {
+		// With no base there is nothing to anchor an absolute URL to. Return empty
+		// so the caller omits the return URLs entirely (client.Pay skips empty ones,
+		// leaving the backend's generic checkout) instead of emitting a broken
+		// relative "/checkout?...".
+		return "", ""
+	}
+	token := url.QueryEscape(sessionToken)
+	return base + "/checkout?checkout=success&partnerCheckout=1&sessionToken=" + token,
+		base + "/checkout?checkout=cancel&partnerCheckout=1&sessionToken=" + token
+}
+
+// BuildPartnerReturnURL returns the https page the browser is sent back to once
+// the partner checkout or OAuth consent completes — the aimlapi web app the user
+// opened the flow from. frontendBaseURL is normally endpoints.VerificationBaseURL
+// (the front that hosts the login/consent page), so the return follows the same
+// environment. AIMLAPI_RETURN_URL overrides it outright; an empty base falls back
+// to DefaultReturnURL. It is deliberately NOT a custom scheme (zero://…): no
+// browser can hand a custom scheme off without an OS-registered handler, which a
+// CLI does not install.
+func BuildPartnerReturnURL(frontendBaseURL string) string {
+	if override := strings.TrimSpace(os.Getenv("AIMLAPI_RETURN_URL")); override != "" {
+		return override
+	}
+	if base := strings.TrimRight(strings.TrimSpace(frontendBaseURL), "/"); base != "" {
+		return base
+	}
+	return DefaultReturnURL
+}
+
+func envOrDefault(name string, fallback string) string {
+	if value := strings.TrimSpace(os.Getenv(name)); value != "" {
+		return value
+	}
+	return fallback
+}

internal/aimlapi/config_test.go

@@ -0,0 +1,55 @@
+package aimlapi
+
+import "testing"
+
+func TestResolveEndpointsDefaults(t *testing.T) {
+	t.Setenv("AIMLAPI_AUTH_URL", "")
+	t.Setenv("AIMLAPI_APP_URL", "")
+	t.Setenv("AIMLAPI_INFERENCE_URL", "")
+	t.Setenv("AIMLAPI_PAY_URL", "")
+
+	endpoints := ResolveEndpoints()
+	if endpoints.AuthBaseURL != "https://auth.aimlapi.com" ||
+		endpoints.AppBaseURL != "https://app.aimlapi.com" ||
+		endpoints.InferenceBaseURL != "https://api.aimlapi.com/v1" ||
+		endpoints.PayBaseURL != "https://pay.aimlapi.com" {
+		t.Fatalf("unexpected endpoints: %#v", endpoints)
+	}
+}
+
+func TestResolvedPartnerHeaderUsesEnvironmentOverrideWithoutDuplicates(t *testing.T) {
+	t.Setenv("AIMLAPI_PARTNER_ID", "part_override")
+
+	headers := WithResolvedPartnerHeader(map[string]string{
+		"x-aimlapi-partner-id":       "part_catalog",
+		"X-AIMLAPI-Integration-Repo": "Gitlawb/zero",
+	})
+
+	if got := headers[PartnerHeaderName]; got != "part_override" {
+		t.Fatalf("partner header = %q, want part_override", got)
+	}
+	if _, ok := headers["x-aimlapi-partner-id"]; ok {
+		t.Fatalf("case-insensitive partner header was duplicated: %#v", headers)
+	}
+	if got := headers["X-AIMLAPI-Integration-Repo"]; got != "Gitlawb/zero" {
+		t.Fatalf("unrelated header changed: %#v", headers)
+	}
+}
+
+func TestBuildPartnerReturnURL(t *testing.T) {
+	t.Setenv("AIMLAPI_RETURN_URL", "")
+	// The frontend base (the web app the flow was opened from) is returned as-is,
+	// trailing slash trimmed — an https page the browser can actually land on.
+	if got := BuildPartnerReturnURL("https://aimlapi.com/app/"); got != "https://aimlapi.com/app" {
+		t.Fatalf("return URL = %q, want the frontend base", got)
+	}
+	// An empty base falls back to the https default, never a custom scheme.
+	if got := BuildPartnerReturnURL(""); got != DefaultReturnURL {
+		t.Fatalf("empty base return URL = %q, want %q", got, DefaultReturnURL)
+	}
+
+	t.Setenv("AIMLAPI_RETURN_URL", "https://example.test/done")
+	if got := BuildPartnerReturnURL("https://aimlapi.com/app"); got != "https://example.test/done" {
+		t.Fatalf("env override return URL = %q", got)
+	}
+}

internal/aimlapi/messages.go

@@ -0,0 +1,42 @@
+package aimlapi
+
+// UI strings shared by the first-run and provider-wizard onboarding surfaces.
+
+const (
+	// Path A — existing API key. Pick-path prompt + option labels.
+	MsgAPIKeyInputPrompt = "Enter your aimlapi.com key."
+	MsgAPIKeyInvalid     = "API key is invalid. Please make sure you enter a valid aimlapi.com key."
+	MsgPickPathPrompt    = "Do you have aimlapi.com key?"
+	MsgPickPathHaveKey   = "I already have aimlapi.com key"
+	MsgPickPathHaveHint  = "Proceed to paste the key"
+	MsgPickPathNewUser   = "I am a new user"
+	MsgPickPathNewHint   = "One click set up"
+	// Path B — email.
+	MsgEnterEmail           = "Enter your email.\nTo access aimlapi.com dashboard."
+	MsgEmailInvalid         = "Email format is incorrect."
+	MsgAccountActionInvalid = "aimlapi.com returned an unsupported account action. Please try again."
+	// %s = email
+	MsgCodeSent      = "We sent a 6-digit code to %s.\nEnter it below to continue."
+	MsgCodeIncorrect = "Code you've entered is incorrect."
+
+	// Balance check.
+	MsgLowBalance     = "Your aimlapi.com balance is running low.\nIt is recommended to top up your balance."
+	MsgEverythingRuns = "Everything is ready."
+	// Low-balance choices (spec wording).
+	MsgLowBalanceTopUp = "Sure, let's do that"
+	MsgLowBalanceSkip  = "I'll skip topping up the balance for now"
+
+	// Top-up workflow.
+	MsgTopUpPrompt    = "Add credits.\nEnter an amount (min $20)."
+	MsgAmountRequired = "Please enter a top-up amount."
+	// %s = checkout URL
+	MsgTopUpBrowserFallback = "If the browser did not open automatically please use this link to top up your account: %s"
+	MsgTopUpFailed          = "Top up failed. Please try again."
+	MsgTopUpSuccess         = "Top-up successful."
+
+	// Success — key delivered.
+	// %s = amount in dollars (e.g. "25")
+	MsgTopUpAddedFmt = "$%s has been added to your balance."
+	// %s = email
+	MsgSuccessMagicLink = "We've emailed you a magic link to %s. Use it to access your aimlapi.com account and review your usage and balance."
+)

internal/aimlapi/onboard_test.go

@@ -0,0 +1,26 @@
+package aimlapi
+
+import "testing"
+
+func TestValidEmailRejectsIncompleteDomains(t *testing.T) {
+	tests := []struct {
+		value string
+		valid bool
+	}{
+		{value: "[email protected]", valid: true},
+		{value: "[email protected]", valid: true},
+		{value: "123@123.", valid: false},
+		{value: "123@123", valid: false},
+		{value: "[email protected]", valid: false},
+		{value: "[email protected]", valid: false},
+		{value: "[email protected]", valid: false},
+		{value: "[email protected]", valid: false},
+	}
+	for _, test := range tests {
+		t.Run(test.value, func(t *testing.T) {
+			if got := ValidEmail(test.value); got != test.valid {
+				t.Fatalf("ValidEmail(%q) = %v, want %v", test.value, got, test.valid)
+			}
+		})
+	}
+}

internal/aimlapi/stream.go

@@ -0,0 +1,335 @@
+package aimlapi
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+	"net/url"
+	"strings"
+)
+
+// StreamTopUpOptions drives a session-based partner-checkout top-up for the
+// interactive (TUI) onboarding. The caller already holds a user session —
+// obtained from an email-code sign-in (Path B existing) or a
+// passwordless new account (Path B sign-up) — so this skips authentication and
+// runs create-session → pay → wait-for-payment, optionally exchanging the paid
+// session into a fresh key (new accounts) versus keeping the caller's key.
+type StreamTopUpOptions struct {
+	SessionToken string // user session bearer (required)
+	AmountUSD    string // dollars; parsed via ParseAmountUSD (min $20)
+	// InferenceBaseURL pins key-bound billing and the returned provider profile to
+	// the endpoint that validated the credential. Empty uses ResolveEndpoints.
+	InferenceBaseURL string
+	Method           PaymentMethod
+	AutoTopUp        bool // enroll the account in automatic top-up at checkout time
+	Exchange         bool // exchange the paid session into a new key (new accounts)
+	Model            string
+	PartnerID        string
+	PartnerName      string
+	NoOpen           bool
+
+	// ResumeSessionToken, when set, resumes that partner-checkout session instead
+	// of opening a new one, so a retry after an ambiguous failure (a lost Pay/
+	// Exchange response) can never double-charge or strand an already-paid session.
+	ResumeSessionToken string
+	// PaymentSessionID is generated once per amount/auto-top-up intent and reused
+	// on retry so an ambiguous Pay response cannot create a second checkout.
+	PaymentSessionID string
+
+	HTTPClient  *http.Client
+	OpenBrowser func(string) error
+	OnStatus    func(Status, string)
+	// OnSession reports the partner-checkout session token the moment it exists (a
+	// fresh CreateSession, or the resumed one), so the caller can retain it and
+	// resume on a later failure. It fires with "" when the session is dead and the
+	// retained token should be dropped (a fresh run must start over).
+	OnSession func(sessionToken string)
+}
+
+// topupPhase is where StreamTopUp enters its create-checkout → poll → exchange
+// pipeline. A fresh run starts at phasePay; a resume skips ahead to whatever the
+// existing session's status makes safe.
+type topupPhase int
+
+const (
+	phasePay          topupPhase = iota // (re-)open the Stripe checkout, then poll + exchange
+	phasePoll                           // checkout already open; poll for payment, never re-pay
+	phaseExchange                       // already paid; exchange only (recovers a lost key)
+	phaseWaitExchange                   // an exchange claim is in flight; poll, never call Exchange twice
+)
+
+// StreamTopUp performs the browser-checkout top-up and reports progress via
+// OnStatus.
+func StreamTopUp(ctx context.Context, options StreamTopUpOptions) (ProvisionedKey, error) {
+	endpoints := ResolveEndpoints()
+	if baseURL := strings.TrimSpace(options.InferenceBaseURL); baseURL != "" {
+		endpoints.InferenceBaseURL = baseURL
+	}
+	client := NewClient(endpoints, options.HTTPClient)
+	partnerID := ResolvePartnerID(options.PartnerID)
+	partnerName := firstNonEmpty(options.PartnerName, DefaultPartnerName)
+	method := options.Method
+	if method != PaymentMethodCrypto {
+		method = PaymentMethodCard
+	}
+	amount, err := ParseAmountUSD(options.AmountUSD)
+	if err != nil {
+		return ProvisionedKey{}, err
+	}
+	if strings.TrimSpace(options.SessionToken) == "" {
+		return ProvisionedKey{}, fmt.Errorf("a session is required to top up")
+	}
+	if strings.TrimSpace(options.PaymentSessionID) == "" {
+		return ProvisionedKey{}, fmt.Errorf("a payment session id is required to top up")
+	}
+
+	status(options.OnStatus, StatusCreatingSession, "")
+	sessionToken, phase, err := resolveTopupSession(ctx, client, options, partnerID, partnerName, endpoints)
+	if err != nil {
+		return ProvisionedKey{}, err
+	}
+	// Retain the live token so an ambiguous failure below can resume this session
+	// rather than open a second checkout on the next attempt.
+	reportSession(options.OnSession, sessionToken)
+
+	if phase <= phasePay {
+		successURL, cancelURL := BuildPartnerCheckoutReturnURLs(endpoints.PayBaseURL, sessionToken)
+		status(options.OnStatus, StatusOpeningCheckout, "")
+		pay, err := client.Pay(ctx, options.SessionToken, sessionToken, amount, options.PaymentSessionID, method, successURL, cancelURL, options.AutoTopUp)
+		if err != nil {
+			return ProvisionedKey{}, err
+		}
+		checkoutURL, err := validatedCheckoutURL(pay.Checkout.PayURL)
+		if err != nil {
+			return ProvisionedKey{}, err
+		}
+		announceCheckout(options.OnStatus, options.OpenBrowser, options.NoOpen, checkoutURL)
+	}
+
+	paidToken := sessionToken
+	if phase <= phasePoll {
+		status(options.OnStatus, StatusWaitingPayment, "")
+		paid, err := pollUntilPaid(ctx, client, sessionToken, options.OnSession)
+		if err != nil {
+			return ProvisionedKey{}, err
+		}
+		paidToken = paid.SessionToken
+		if paid.Status == SessionStatusExchanging {
+			// Another/lost request claimed exchange while we were polling payment.
+			// Carry that fact into the provisioning branch so it follows the claim
+			// instead of issuing a second single-flight Exchange request.
+			phase = phaseWaitExchange
+		}
+	}
+
+	result := ProvisionedKey{
+		BaseURL: endpoints.InferenceBaseURL,
+		Model:   firstNonEmpty(options.Model, DefaultModel),
+	}
+	if options.Exchange {
+		status(options.OnStatus, StatusProvisioningKey, "")
+		if phase == phaseWaitExchange {
+			return ProvisionedKey{}, pollUntilExchangeSettled(ctx, client, sessionToken, options.OnSession)
+		}
+		exchange, err := client.Exchange(ctx, options.SessionToken, paidToken)
+		if err != nil {
+			return ProvisionedKey{}, err
+		}
+		if strings.TrimSpace(exchange.APIKey) == "" {
+			return ProvisionedKey{}, fmt.Errorf("aimlapi.com did not return an API key")
+		}
+		result.APIKey = exchange.APIKey
+		result.APIKeyID = exchange.APIKeyID
+	}
+	return result, nil
+}
+
+// resolveTopupSession returns the partner-checkout session token to drive and the
+// phase to enter. A fresh run opens a new session at phasePay. A resume inspects
+// the existing session and enters the earliest phase that cannot re-charge:
+//   - pending_auth    → phasePay: payment never started, so (re-)Pay is safe.
+//   - pending_payment → phasePoll: a checkout is already open; poll, never re-Pay.
+//   - paid            → phaseExchange: exchange the paid session once.
+//   - exchanging      → phaseWaitExchange: another/lost request owns the atomic
+//     exchange claim; poll it, never issue a second Exchange request.
+//   - exchanged       → terminal: the one-shot raw key is gone; point at dashboard
+//     recovery and keep the token so a re-run repeats that guidance, not a charge.
+//   - cancelled/expired/failed → terminal: drop the dead token so a re-run is fresh.
+func resolveTopupSession(ctx context.Context, client *Client, options StreamTopUpOptions, partnerID, partnerName string, endpoints Endpoints) (string, topupPhase, error) {
+	resume := strings.TrimSpace(options.ResumeSessionToken)
+	if resume == "" {
+		session, err := client.CreateSession(ctx, partnerID, partnerName, BuildPartnerReturnURL(endpoints.VerificationBaseURL))
+		if err != nil {
+			return "", phasePay, err
+		}
+		return session.SessionToken, phasePay, nil
+	}
+	session, err := client.GetSession(ctx, resume)
+	if err != nil {
+		if isTerminalSessionAPIError(err) {
+			reportSession(options.OnSession, "")
+		}
+		return "", phasePay, err
+	}
+	switch session.Status {
+	case SessionStatusPendingAuth:
+		return resume, phasePay, nil
+	case SessionStatusPendingPayment:
+		return resume, phasePoll, nil
+	case SessionStatusPaid:
+		return resume, phaseExchange, nil
+	case SessionStatusExchanging:
+		return resume, phaseWaitExchange, nil
+	case SessionStatusExchanged:
+		return "", phasePay, fmt.Errorf("session was already exchanged; rotate the key from the aimlapi.com dashboard")
+	default:
+		reportSession(options.OnSession, "") // drop the dead token → next run starts fresh
+		return "", phasePay, fmt.Errorf("payment %s; re-run the top-up to try again", session.Status)
+	}
+}
+
+func reportSession(callback func(string), sessionToken string) {
+	if callback != nil {
+		callback(sessionToken)
+	}
+}
+
+// announceCheckout opens the hosted checkout in the browser (unless suppressed)
+// and reports the URL either way, so the TUI can always show the direct link.
+func announceCheckout(onStatus func(Status, string), open func(string) error, noOpen bool, checkoutURL string) {
+	if noOpen || open == nil {
+		status(onStatus, StatusOpeningCheckout, checkoutURL)
+		return
+	}
+	if err := open(checkoutURL); err != nil {
+		status(onStatus, StatusOpeningCheckout, "Open manually: "+checkoutURL)
+		return
+	}
+	status(onStatus, StatusOpeningCheckout, checkoutURL)
+}
+
+func validatedCheckoutURL(value string) (string, error) {
+	checkoutURL := strings.TrimSpace(value)
+	parsed, err := url.Parse(checkoutURL)
+	if err != nil || !parsed.IsAbs() || !strings.EqualFold(parsed.Scheme, "https") || parsed.Hostname() == "" || parsed.User != nil {
+		return "", fmt.Errorf("payment provider did not return a valid HTTPS checkout URL")
+	}
+	return checkoutURL, nil
+}
+
+// StreamTopUpByKeyOptions drives a top-up funded with the API key that already
+// owns the account (Path A pasted key, or AIMLAPI_API_KEY). Unlike StreamTopUp it
+// needs no email session and never exchanges a key — the caller already holds one,
+// so it only funds the wallet: create-session → pay-by-key → wait-for-payment.
+type StreamTopUpByKeyOptions struct {
+	APIKey           string // raw key that owns the account (required)
+	AmountUSD        string // dollars; parsed via ParseAmountUSD (min $20)
+	InferenceBaseURL string // validated key endpoint; empty uses ResolveEndpoints
+	AutoTopUp        bool   // enroll the account in automatic top-up at checkout time
+	PartnerID        string
+	PartnerName      string
+	NoOpen           bool
+
+	// ResumeSessionToken resumes an existing partner-checkout session instead of
+	// opening a new one. PaymentSessionID is the idempotency handle carried across
+	// retries so a re-issued pay returns the same checkout, never a second charge.
+	ResumeSessionToken string
+	PaymentSessionID   string // required; generate once via NewPaymentSessionID, reuse on retry
+
+	HTTPClient  *http.Client
+	OpenBrowser func(string) error
+	OnStatus    func(Status, string)
+	OnSession   func(sessionToken string)
+}
+
+// StreamTopUpByKey funds the account behind APIKey via the hosted checkout and
+// reports progress through OnStatus. It returns an empty ProvisionedKey: the
+// pasted/env key is unchanged, only the balance grows.
+func StreamTopUpByKey(ctx context.Context, options StreamTopUpByKeyOptions) (ProvisionedKey, error) {
+	endpoints := ResolveEndpoints()
+	if baseURL := strings.TrimSpace(options.InferenceBaseURL); baseURL != "" {
+		endpoints.InferenceBaseURL = baseURL
+	}
+	client := NewClient(endpoints, options.HTTPClient)
+	partnerID := ResolvePartnerID(options.PartnerID)
+	partnerName := firstNonEmpty(options.PartnerName, DefaultPartnerName)
+	amount, err := ParseAmountUSD(options.AmountUSD)
+	if err != nil {
+		return ProvisionedKey{}, err
+	}
+	if strings.TrimSpace(options.APIKey) == "" {
+		return ProvisionedKey{}, fmt.Errorf("an API key is required to top up")
+	}
+	if strings.TrimSpace(options.PaymentSessionID) == "" {
+		return ProvisionedKey{}, fmt.Errorf("a payment session id is required to top up")
+	}
+
+	status(options.OnStatus, StatusCreatingSession, "")
+	sessionToken, phase, err := resolveByKeySession(ctx, client, options, partnerID, partnerName, endpoints)
+	if err != nil {
+		return ProvisionedKey{}, err
+	}
+	reportSession(options.OnSession, sessionToken)
+
+	if phase <= phasePay {
+		successURL, cancelURL := BuildPartnerCheckoutReturnURLs(endpoints.PayBaseURL, sessionToken)
+		status(options.OnStatus, StatusOpeningCheckout, "")
+		pay, err := client.TopUpByKey(ctx, options.APIKey, TopUpByKeyRequest{
+			SessionToken:     sessionToken,
+			AmountUSDMinor:   amount,
+			PaymentSessionID: options.PaymentSessionID,
+			AutoTopUp:        options.AutoTopUp,
+			SuccessURL:       successURL,
+			CancelURL:        cancelURL,
+		})
+		if err != nil {
+			return ProvisionedKey{}, err
+		}
+		checkoutURL, err := validatedCheckoutURL(pay.Checkout.PayURL)
+		if err != nil {
+			return ProvisionedKey{}, err
+		}
+		announceCheckout(options.OnStatus, options.OpenBrowser, options.NoOpen, checkoutURL)
+	}
+
+	if phase <= phasePoll {
+		status(options.OnStatus, StatusWaitingPayment, "")
+		if _, err := pollUntilPaid(ctx, client, sessionToken, options.OnSession); err != nil {
+			return ProvisionedKey{}, err
+		}
+	}
+	// No exchange: the account is funded and the caller keeps its existing key.
+	return ProvisionedKey{}, nil
+}
+
+// resolveByKeySession mirrors resolveTopupSession for the by-key flow. Because
+// by-key never exchanges, a paid/exchanging/exchanged session all mean "already
+// funded, done" (phaseExchange skips straight past pay + poll to the empty result).
+func resolveByKeySession(ctx context.Context, client *Client, options StreamTopUpByKeyOptions, partnerID, partnerName string, endpoints Endpoints) (string, topupPhase, error) {
+	resume := strings.TrimSpace(options.ResumeSessionToken)
+	if resume == "" {
+		session, err := client.CreateSession(ctx, partnerID, partnerName, BuildPartnerReturnURL(endpoints.VerificationBaseURL))
+		if err != nil {
+			return "", phasePay, err
+		}
+		return session.SessionToken, phasePay, nil
+	}
+	session, err := client.GetSession(ctx, resume)
+	if err != nil {
+		if isTerminalSessionAPIError(err) {
+			reportSession(options.OnSession, "")
+		}
+		return "", phasePay, err
+	}
+	switch session.Status {
+	case SessionStatusPendingAuth:
+		return resume, phasePay, nil
+	case SessionStatusPendingPayment:
+		return resume, phasePoll, nil
+	case SessionStatusPaid, SessionStatusExchanging, SessionStatusExchanged:
+		return resume, phaseExchange, nil
+	default:
+		reportSession(options.OnSession, "") // drop the dead token → next run starts fresh
+		return "", phasePay, fmt.Errorf("payment %s; re-run the top-up to try again", session.Status)
+	}
+}

internal/aimlapi/stream_test.go

@@ -0,0 +1,457 @@
+package aimlapi
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+)
+
+func TestStreamTopUpByKeyFundsWithoutExchange(t *testing.T) {
+	var topupCalls, exchangeCalls int
+	var topupBody map[string]any
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		switch {
+		case r.Method == http.MethodPost && strings.HasSuffix(r.URL.Path, "/partner-checkout/sessions"):
+			_ = json.NewEncoder(w).Encode(PartnerCheckoutSession{SessionToken: "pcs_tok", Status: SessionStatusPendingAuth})
+		case r.Method == http.MethodPost && strings.HasSuffix(r.URL.Path, "/v2/billing/topup"):
+			topupCalls++
+			_ = json.NewDecoder(r.Body).Decode(&topupBody)
+			_ = json.NewEncoder(w).Encode(TopUpByKeyResult{Checkout: PaymentSession{PayURL: "https://pay/checkout"}})
+		case r.Method == http.MethodGet && strings.Contains(r.URL.Path, "/partner-checkout/sessions/"):
+			_ = json.NewEncoder(w).Encode(PartnerCheckoutSession{SessionToken: "pcs_tok", Status: SessionStatusPaid})
+		case r.Method == http.MethodPost && strings.HasSuffix(r.URL.Path, "/exchange"):
+			exchangeCalls++
+			t.Errorf("by-key must never exchange a key")
+		default:
+			t.Errorf("unexpected request: %s %s", r.Method, r.URL.Path)
+		}
+	}))
+	defer server.Close()
+	t.Setenv("AIMLAPI_APP_URL", server.URL)
+	t.Setenv("AIMLAPI_INFERENCE_URL", server.URL+"/v1")
+
+	var opened string
+	result, err := StreamTopUpByKey(context.Background(), StreamTopUpByKeyOptions{
+		APIKey:           "sk-user",
+		AmountUSD:        "20",
+		AutoTopUp:        true,
+		PaymentSessionID: "pay-1",
+		OpenBrowser:      func(u string) error { opened = u; return nil },
+	})
+	if err != nil {
+		t.Fatalf("StreamTopUpByKey = %v", err)
+	}
+	if result.APIKey != "" {
+		t.Fatalf("by-key must not mint a key, got %q", result.APIKey)
+	}
+	if topupCalls != 1 || exchangeCalls != 0 {
+		t.Fatalf("topup=%d exchange=%d, want 1/0", topupCalls, exchangeCalls)
+	}
+	if opened != "https://pay/checkout" {
+		t.Fatalf("opened checkout = %q", opened)
+	}
+	if topupBody["autoTopUp"] != true || topupBody["paymentSessionId"] != "pay-1" {
+		t.Fatalf("topup body missing autoTopUp/paymentSessionId: %#v", topupBody)
+	}
+}
+
+func TestValidatedCheckoutURLRequiresAbsoluteHTTPS(t *testing.T) {
+	tests := []struct {
+		name    string
+		value   string
+		want    string
+		wantErr bool
+	}{
+		{name: "https", value: " https://pay.example.test/checkout?id=1 ", want: "https://pay.example.test/checkout?id=1"},
+		{name: "empty", wantErr: true},
+		{name: "relative", value: "/checkout", wantErr: true},
+		{name: "http", value: "http://pay.example.test/checkout", wantErr: true},
+		{name: "file", value: "file:///tmp/checkout", wantErr: true},
+		{name: "custom protocol", value: "wallet://checkout/123", wantErr: true},
+		{name: "userinfo", value: "https://[email protected]/checkout", wantErr: true},
+	}
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			got, err := validatedCheckoutURL(test.value)
+			if (err != nil) != test.wantErr {
+				t.Fatalf("validatedCheckoutURL(%q) error = %v", test.value, err)
+			}
+			if got != test.want {
+				t.Fatalf("validatedCheckoutURL(%q) = %q, want %q", test.value, got, test.want)
+			}
+		})
+	}
+}
+
+func TestStreamTopUpByKeyPinsValidatedInferenceEndpoint(t *testing.T) {
+	validatedCalls := 0
+	validated := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		switch {
+		case r.Method == http.MethodPost && strings.HasSuffix(r.URL.Path, "/partner-checkout/sessions"):
+			_ = json.NewEncoder(w).Encode(PartnerCheckoutSession{SessionToken: "pcs_tok", Status: SessionStatusPendingAuth})
+		case r.Method == http.MethodPost && strings.HasSuffix(r.URL.Path, "/v2/billing/topup"):
+			validatedCalls++
+			_ = json.NewEncoder(w).Encode(TopUpByKeyResult{Checkout: PaymentSession{PayURL: "https://pay/checkout"}})
+		case r.Method == http.MethodGet && strings.Contains(r.URL.Path, "/partner-checkout/sessions/"):
+			_ = json.NewEncoder(w).Encode(PartnerCheckoutSession{SessionToken: "pcs_tok", Status: SessionStatusPaid})
+		default:
+			t.Errorf("unexpected validated-endpoint request: %s %s", r.Method, r.URL.Path)
+		}
+	}))
+	defer validated.Close()
+	override := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		t.Errorf("validated key leaked to process override: %s %s", r.Method, r.URL.Path)
+	}))
+	defer override.Close()
+	t.Setenv("AIMLAPI_APP_URL", validated.URL)
+	t.Setenv("AIMLAPI_INFERENCE_URL", override.URL)
+
+	_, err := StreamTopUpByKey(context.Background(), StreamTopUpByKeyOptions{
+		APIKey:           "production-key",
+		AmountUSD:        "20",
+		InferenceBaseURL: validated.URL,
+		PaymentSessionID: "payment-1",
+		OpenBrowser:      func(string) error { return nil },
+	})
+	if err != nil {
+		t.Fatalf("StreamTopUpByKey() error = %v", err)
+	}
+	if validatedCalls != 1 {
+		t.Fatalf("validated endpoint top-up calls = %d, want 1", validatedCalls)
+	}
+}
+
+func TestStreamTopUpEmailRetrySendsStablePaymentSessionID(t *testing.T) {
+	getCalls := 0
+	var paymentSessionID string
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		switch {
+		case r.Method == http.MethodGet && strings.Contains(r.URL.Path, "/partner-checkout/sessions/"):
+			status := SessionStatusPendingAuth
+			if getCalls > 0 {
+				status = SessionStatusPaid
+			}
+			getCalls++
+			_ = json.NewEncoder(w).Encode(PartnerCheckoutSession{SessionToken: "pcs_retry", Status: status})
+		case r.Method == http.MethodPost && strings.HasSuffix(r.URL.Path, "/pay"):
+			var body map[string]any
+			_ = json.NewDecoder(r.Body).Decode(&body)
+			paymentSessionID, _ = body["paymentSessionId"].(string)
+			_ = json.NewEncoder(w).Encode(PayResult{Checkout: PaymentSession{PayURL: "https://pay/checkout"}})
+		default:
+			t.Errorf("unexpected request: %s %s", r.Method, r.URL.Path)
+		}
+	}))
+	defer server.Close()
+	t.Setenv("AIMLAPI_APP_URL", server.URL)
+
+	_, err := StreamTopUp(context.Background(), StreamTopUpOptions{
+		SessionToken:       "bearer",
+		ResumeSessionToken: "pcs_retry",
+		PaymentSessionID:   "payment-stable",
+		AmountUSD:          "20",
+		NoOpen:             true,
+	})
+	if err != nil {
+		t.Fatalf("StreamTopUp() error = %v", err)
+	}
+	if paymentSessionID != "payment-stable" {
+		t.Fatalf("paymentSessionId = %q, want stable retry id", paymentSessionID)
+	}
+}
+
+// resumeServer is a partner-checkout backend fake that fails the test if the
+// re-charging endpoints (create-session / pay) are ever hit, and serves a
+// scripted GetSession status sequence so a resume can be driven deterministically.
+type resumeServer struct {
+	t          *testing.T
+	statuses   []string // GetSession status per call, last value repeats
+	getCalls   int
+	payCalls   int
+	createCall int
+	exchanged  int
+}
+
+func (rs *resumeServer) handler() http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		switch {
+		case r.Method == http.MethodPost && strings.HasSuffix(r.URL.Path, "/partner-checkout/sessions"):
+			rs.createCall++
+			rs.t.Errorf("resume must not create a new session")
+		case r.Method == http.MethodPost && strings.HasSuffix(r.URL.Path, "/pay"):
+			rs.payCalls++
+			rs.t.Errorf("resume must not re-pay (double charge)")
+		case r.Method == http.MethodPost && strings.HasSuffix(r.URL.Path, "/exchange"):
+			rs.exchanged++
+			_ = json.NewEncoder(w).Encode(ExchangeResult{APIKey: "sk-resumed", APIKeyID: "key_1"})
+		case r.Method == http.MethodGet:
+			status := rs.statuses[len(rs.statuses)-1]
+			if rs.getCalls < len(rs.statuses) {
+				status = rs.statuses[rs.getCalls]
+			}
+			rs.getCalls++
+			_ = json.NewEncoder(w).Encode(PartnerCheckoutSession{SessionToken: "pc_tok", Status: SessionStatus(status)})
+		default:
+			rs.t.Errorf("unexpected request: %s %s", r.Method, r.URL.Path)
+		}
+	})
+}
+
+func TestStreamTopUpResumePaidExchangesWithoutRecharge(t *testing.T) {
+	rs := &resumeServer{t: t, statuses: []string{"paid"}}
+	server := httptest.NewServer(rs.handler())
+	defer server.Close()
+	t.Setenv("AIMLAPI_APP_URL", server.URL)
+
+	var seen string
+	result, err := StreamTopUp(context.Background(), StreamTopUpOptions{
+		SessionToken:       "bearer",
+		ResumeSessionToken: "pc_tok",
+		PaymentSessionID:   "payment-1",
+		AmountUSD:          "20",
+		Exchange:           true,
+		NoOpen:             true,
+		OnSession:          func(token string) { seen = token },
+	})
+	if err != nil {
+		t.Fatalf("StreamTopUp resume = %v", err)
+	}
+	if result.APIKey != "sk-resumed" {
+		t.Fatalf("APIKey = %q, want recovered key", result.APIKey)
+	}
+	if rs.exchanged != 1 {
+		t.Fatalf("exchange calls = %d, want 1", rs.exchanged)
+	}
+	if seen != "pc_tok" {
+		t.Fatalf("OnSession token = %q, want retained pc_tok", seen)
+	}
+}
+
+func TestStreamTopUpResumePendingPaymentPollsNeverRepays(t *testing.T) {
+	// First GetSession (resume resolution) sees the still-open checkout; the next
+	// (poll) sees it settle. Pay must never be called — the fake fails the test if
+	// it is.
+	rs := &resumeServer{t: t, statuses: []string{"pending_payment", "paid"}}
+	server := httptest.NewServer(rs.handler())
+	defer server.Close()
+	t.Setenv("AIMLAPI_APP_URL", server.URL)
+
+	result, err := StreamTopUp(context.Background(), StreamTopUpOptions{
+		SessionToken:       "bearer",
+		ResumeSessionToken: "pc_tok",
+		PaymentSessionID:   "payment-1",
+		AmountUSD:          "20",
+		Exchange:           true,
+		NoOpen:             true,
+	})
+	if err != nil {
+		t.Fatalf("StreamTopUp resume = %v", err)
+	}
+	if result.APIKey != "sk-resumed" {
+		t.Fatalf("APIKey = %q, want recovered key", result.APIKey)
+	}
+	if rs.payCalls != 0 {
+		t.Fatalf("pay calls = %d, want 0", rs.payCalls)
+	}
+}
+
+func TestStreamTopUpPollingDeadSessionClearsRetainedToken(t *testing.T) {
+	rs := &resumeServer{t: t, statuses: []string{"pending_payment", "expired"}}
+	server := httptest.NewServer(rs.handler())
+	defer server.Close()
+	t.Setenv("AIMLAPI_APP_URL", server.URL)
+
+	seen := []string{}
+	_, err := StreamTopUp(context.Background(), StreamTopUpOptions{
+		SessionToken:       "bearer",
+		ResumeSessionToken: "pc_tok",
+		PaymentSessionID:   "payment-1",
+		AmountUSD:          "20",
+		Exchange:           true,
+		NoOpen:             true,
+		OnSession:          func(token string) { seen = append(seen, token) },
+	})
+	if err == nil || !strings.Contains(err.Error(), "payment expired") {
+		t.Fatalf("err = %v, want expired payment error", err)
+	}
+	if len(seen) == 0 || seen[len(seen)-1] != "" {
+		t.Fatalf("OnSession events = %#v, want terminal clear", seen)
+	}
+}
+
+func TestPollUntilPaidTerminal4xxClearsRetainedToken(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		http.Error(w, "session rejected", http.StatusNotFound)
+	}))
+	defer server.Close()
+
+	seen := "retained"
+	_, err := pollUntilPaid(context.Background(), NewClient(Endpoints{AppBaseURL: server.URL}, server.Client()), "pc_missing", func(token string) {
+		seen = token
+	})
+	if err == nil {
+		t.Fatal("pollUntilPaid() error = nil, want terminal 4xx")
+	}
+	if seen != "" {
+		t.Fatalf("retained session = %q, want cleared", seen)
+	}
+}
+
+func TestPollUntilExchangeSettledClearsDeadSession(t *testing.T) {
+	for _, test := range []struct {
+		name       string
+		statusCode int
+		status     SessionStatus
+	}{
+		{name: "terminal API rejection", statusCode: http.StatusNotFound},
+		{name: "expired exchange claim", status: SessionStatusExpired},
+	} {
+		t.Run(test.name, func(t *testing.T) {
+			server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+				if test.statusCode != 0 {
+					http.Error(w, "session rejected", test.statusCode)
+					return
+				}
+				_ = json.NewEncoder(w).Encode(PartnerCheckoutSession{SessionToken: "pcs_dead", Status: test.status})
+			}))
+			defer server.Close()
+
+			seen := "retained"
+			err := pollUntilExchangeSettled(context.Background(), NewClient(Endpoints{AppBaseURL: server.URL}, server.Client()), "pcs_dead", func(token string) {
+				seen = token
+			})
+			if err == nil {
+				t.Fatal("pollUntilExchangeSettled() error = nil")
+			}
+			if seen != "" {
+				t.Fatalf("retained session = %q, want cleared", seen)
+			}
+		})
+	}
+}
+
+func TestResumeHelpersClearOnlyRejectedSessions(t *testing.T) {
+	tests := []struct {
+		name      string
+		status    int
+		wantClear bool
+	}{
+		{name: "terminal 4xx", status: http.StatusNotFound, wantClear: true},
+		{name: "retryable 5xx", status: http.StatusServiceUnavailable, wantClear: false},
+	}
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+				http.Error(w, "session lookup failed", test.status)
+			}))
+			defer server.Close()
+			client := NewClient(Endpoints{AppBaseURL: server.URL}, server.Client())
+
+			for _, flow := range []struct {
+				name    string
+				resolve func(func(string)) error
+			}{
+				{
+					name: "session bearer",
+					resolve: func(onSession func(string)) error {
+						_, _, err := resolveTopupSession(context.Background(), client, StreamTopUpOptions{
+							ResumeSessionToken: "pc_rejected", OnSession: onSession,
+						}, DefaultPartnerID, DefaultPartnerName, Endpoints{})
+						return err
+					},
+				},
+				{
+					name: "api key",
+					resolve: func(onSession func(string)) error {
+						_, _, err := resolveByKeySession(context.Background(), client, StreamTopUpByKeyOptions{
+							ResumeSessionToken: "pc_rejected", OnSession: onSession,
+						}, DefaultPartnerID, DefaultPartnerName, Endpoints{})
+						return err
+					},
+				},
+			} {
+				t.Run(flow.name, func(t *testing.T) {
+					seen := "retained"
+					if err := flow.resolve(func(token string) { seen = token }); err == nil {
+						t.Fatal("resolve error = nil")
+					}
+					if cleared := seen == ""; cleared != test.wantClear {
+						t.Fatalf("session cleared = %v, want %v", cleared, test.wantClear)
+					}
+				})
+			}
+		})
+	}
+}
+
+func TestStreamTopUpResumeExchangedReturnsRecoveryError(t *testing.T) {
+	rs := &resumeServer{t: t, statuses: []string{"exchanged"}}
+	server := httptest.NewServer(rs.handler())
+	defer server.Close()
+	t.Setenv("AIMLAPI_APP_URL", server.URL)
+
+	_, err := StreamTopUp(context.Background(), StreamTopUpOptions{
+		SessionToken:       "bearer",
+		ResumeSessionToken: "pc_tok",
+		PaymentSessionID:   "payment-1",
+		AmountUSD:          "20",
+		Exchange:           true,
+		NoOpen:             true,
+	})
+	if err == nil || !strings.Contains(err.Error(), "already exchanged") {
+		t.Fatalf("err = %v, want an already-exchanged recovery error", err)
+	}
+	if rs.exchanged != 0 {
+		t.Fatalf("exchange calls = %d, want 0 (no second key)", rs.exchanged)
+	}
+}
+
+func TestStreamTopUpResumeExchangingPollsWithoutSecondExchange(t *testing.T) {
+	rs := &resumeServer{t: t, statuses: []string{"exchanging", "exchanged"}}
+	server := httptest.NewServer(rs.handler())
+	defer server.Close()
+	t.Setenv("AIMLAPI_APP_URL", server.URL)
+
+	_, err := StreamTopUp(context.Background(), StreamTopUpOptions{
+		SessionToken:       "bearer",
+		ResumeSessionToken: "pc_tok",
+		PaymentSessionID:   "payment-1",
+		AmountUSD:          "20",
+		Exchange:           true,
+		NoOpen:             true,
+	})
+	if err == nil || !strings.Contains(err.Error(), "already exchanged") {
+		t.Fatalf("err = %v, want dashboard recovery guidance", err)
+	}
+	if rs.exchanged != 0 {
+		t.Fatalf("exchange calls = %d, want 0 while an exchange claim is in flight", rs.exchanged)
+	}
+	if rs.createCall != 0 || rs.payCalls != 0 {
+		t.Fatalf("resume created/paid a new checkout: create=%d pay=%d", rs.createCall, rs.payCalls)
+	}
+}
+
+func TestStreamTopUpPollObservesExchangingWithoutSecondExchange(t *testing.T) {
+	rs := &resumeServer{t: t, statuses: []string{"pending_payment", "exchanging", "exchanged"}}
+	server := httptest.NewServer(rs.handler())
+	defer server.Close()
+	t.Setenv("AIMLAPI_APP_URL", server.URL)
+
+	_, err := StreamTopUp(context.Background(), StreamTopUpOptions{
+		SessionToken:       "bearer",
+		ResumeSessionToken: "pc_tok",
+		PaymentSessionID:   "payment-1",
+		AmountUSD:          "20",
+		Exchange:           true,
+		NoOpen:             true,
+	})
+	if err == nil || !strings.Contains(err.Error(), "already exchanged") {
+		t.Fatalf("err = %v, want dashboard recovery guidance", err)
+	}
+	if rs.exchanged != 0 {
+		t.Fatalf("exchange calls = %d, want 0 after poll observed an existing claim", rs.exchanged)
+	}
+}

internal/aimlapi/topup.go

@@ -0,0 +1,186 @@
+package aimlapi
+
+import (
+	"context"
+	"crypto/rand"
+	"errors"
+	"fmt"
+	"math"
+	"net/http"
+	"strconv"
+	"strings"
+	"time"
+)
+
+// Status is a progress phase reported by StreamTopUp through its OnStatus callback.
+type Status string
+
+const (
+	StatusCreatingSession Status = "creating-session"
+	StatusOpeningCheckout Status = "opening-checkout"
+	StatusWaitingPayment  Status = "waiting-payment"
+	StatusProvisioningKey Status = "provisioning-key"
+)
+
+// ProvisionedKey is the outcome of a top-up: the (optionally minted) API key plus
+// the inference base URL and model to write into the provider profile.
+type ProvisionedKey struct {
+	APIKey   string
+	APIKeyID string
+	BaseURL  string
+	Model    string
+}
+
+const (
+	pollInterval = 3 * time.Second
+	pollTimeout  = 20 * time.Minute
+)
+
+// ParseAmountUSD parses a dollar string into USD minor units (cents), enforcing the
+// min/max top-up bounds. An empty value yields the default amount.
+func ParseAmountUSD(value string) (int, error) {
+	value = strings.TrimSpace(value)
+	if value == "" {
+		return DefaultAmountUSDMinor, nil
+	}
+	dollars, err := strconv.ParseFloat(value, 64)
+	// NaN/±Inf parse without error and slip past the min/max comparisons below
+	// (every ordered comparison with NaN is false), so reject them explicitly
+	// before the cents conversion turns them into a garbage minor-unit amount.
+	if err != nil || math.IsNaN(dollars) || math.IsInf(dollars, 0) || dollars <= 0 {
+		return 0, fmt.Errorf("invalid amount %q; pass a positive USD amount", value)
+	}
+	minor := int(dollars*100 + 0.5)
+	if minor < MinAmountUSDMinor {
+		return 0, fmt.Errorf("minimum top-up is $%d", MinAmountUSDMinor/100)
+	}
+	if minor > MaxAmountUSDMinor {
+		return 0, fmt.Errorf("maximum top-up is $%d", MaxAmountUSDMinor/100)
+	}
+	return minor, nil
+}
+
+// NewPaymentSessionID returns a random UUIDv4-shaped idempotency id for a top-up.
+// The caller generates it once per top-up intent and reuses it on retry so the
+// backend (and Stripe) coalesce retries onto the same checkout instead of a
+// second charge.
+func NewPaymentSessionID() (string, error) {
+	var b [16]byte
+	if _, err := rand.Read(b[:]); err != nil {
+		return "", err
+	}
+	b[6] = (b[6] & 0x0f) | 0x40 // version 4
+	b[8] = (b[8] & 0x3f) | 0x80 // variant 10
+	return fmt.Sprintf("%x-%x-%x-%x-%x", b[0:4], b[4:6], b[6:8], b[8:10], b[10:16]), nil
+}
+
+func pollUntilPaid(ctx context.Context, client *Client, sessionToken string, onSession func(string)) (PartnerCheckoutSession, error) {
+	deadline := time.Now().Add(pollTimeout)
+	for time.Now().Before(deadline) {
+		session, err := client.GetSession(ctx, sessionToken)
+		if err != nil {
+			// Context cancellation/deadline is terminal (also covers an in-flight
+			// request cancelled mid-poll, whose transport error wraps ctx.Err()).
+			if errors.Is(err, context.Canceled) || errors.Is(err, context.DeadlineExceeded) {
+				return PartnerCheckoutSession{}, err
+			}
+			// A 4xx API response is terminal. Everything else — a 5xx or a transient
+			// transport error (non-APIError, e.g. a dropped connection during the
+			// wait) — is retried until the poll deadline.
+			if isTerminalSessionAPIError(err) {
+				reportSession(onSession, "")
+				return PartnerCheckoutSession{}, err
+			}
+			if err := sleepContext(ctx, pollInterval); err != nil {
+				return PartnerCheckoutSession{}, err
+			}
+			continue
+		}
+		switch session.Status {
+		case SessionStatusPaid, SessionStatusExchanging:
+			return session, nil
+		case SessionStatusExchanged:
+			return PartnerCheckoutSession{}, fmt.Errorf("session was already exchanged; rotate the key from the aimlapi.com dashboard")
+		case SessionStatusCancelled, SessionStatusExpired, SessionStatusFailed:
+			// The checkout cannot recover from these states. Drop the retained token
+			// (and the TUI's paired by-key idempotency ID) now so the very next retry
+			// creates a fresh payment intent.
+			reportSession(onSession, "")
+			return PartnerCheckoutSession{}, fmt.Errorf("payment %s; re-run the top-up to try again", session.Status)
+		default:
+			if err := sleepContext(ctx, pollInterval); err != nil {
+				return PartnerCheckoutSession{}, err
+			}
+		}
+	}
+	return PartnerCheckoutSession{}, fmt.Errorf("timed out waiting for payment; re-run once the payment clears")
+}
+
+func isTerminalSessionAPIError(err error) bool {
+	var apiErr APIError
+	return errors.As(err, &apiErr) && apiErr.Status >= http.StatusBadRequest && apiErr.Status < http.StatusInternalServerError
+}
+
+// pollUntilExchangeSettled follows an exchange claim that was already in flight
+// when a retry resumed the session. Exchange is single-flight and the raw key is
+// returned only to the winning request, so issuing Exchange again is never safe.
+// Once the claim completes, direct the user to the dashboard recovery path.
+func pollUntilExchangeSettled(ctx context.Context, client *Client, sessionToken string, onSession func(string)) error {
+	deadline := time.Now().Add(pollTimeout)
+	for time.Now().Before(deadline) {
+		session, err := client.GetSession(ctx, sessionToken)
+		if err != nil {
+			if errors.Is(err, context.Canceled) || errors.Is(err, context.DeadlineExceeded) {
+				return err
+			}
+			if isTerminalSessionAPIError(err) {
+				reportSession(onSession, "")
+				return err
+			}
+			if err := sleepContext(ctx, pollInterval); err != nil {
+				return err
+			}
+			continue
+		}
+		switch session.Status {
+		case SessionStatusExchanged:
+			return fmt.Errorf("session was already exchanged; rotate the key from the aimlapi.com dashboard")
+		case SessionStatusExchanging:
+			if err := sleepContext(ctx, pollInterval); err != nil {
+				return err
+			}
+		case SessionStatusCancelled, SessionStatusExpired, SessionStatusFailed:
+			reportSession(onSession, "")
+			return fmt.Errorf("key provisioning %s; rotate the key from the aimlapi.com dashboard", session.Status)
+		default:
+			return fmt.Errorf("key provisioning returned to %s; re-run the top-up", session.Status)
+		}
+	}
+	return fmt.Errorf("timed out waiting for key provisioning; retry to check the same session")
+}
+
+func sleepContext(ctx context.Context, delay time.Duration) error {
+	timer := time.NewTimer(delay)
+	defer timer.Stop()
+	select {
+	case <-ctx.Done():
+		return ctx.Err()
+	case <-timer.C:
+		return nil
+	}
+}
+
+func status(callback func(Status, string), value Status, detail string) {
+	if callback != nil {
+		callback(value, detail)
+	}
+}
+
+func firstNonEmpty(values ...string) string {
+	for _, value := range values {
+		if value = strings.TrimSpace(value); value != "" {
+			return value
+		}
+	}
+	return ""
+}

internal/aimlapi/validation.go

@@ -0,0 +1,38 @@
+package aimlapi
+
+import (
+	"net/mail"
+	"strings"
+)
+
+// ValidEmail performs the lightweight validation used before starting the
+// passwordless onboarding request.
+func ValidEmail(value string) bool {
+	value = strings.TrimSpace(value)
+	address, err := mail.ParseAddress(value)
+	if err != nil || address.Address != value {
+		return false
+	}
+	at := strings.LastIndexByte(value, '@')
+	if at <= 0 || at == len(value)-1 {
+		return false
+	}
+	domain := value[at+1:]
+	if strings.HasPrefix(domain, ".") || strings.HasSuffix(domain, ".") || strings.Contains(domain, "..") {
+		return false
+	}
+	dot := strings.LastIndexByte(domain, '.')
+	if dot <= 0 || dot == len(domain)-1 {
+		return false
+	}
+	tld := domain[dot+1:]
+	if len(tld) < 2 {
+		return false
+	}
+	for _, char := range tld {
+		if char < 'A' || char > 'Z' && char < 'a' || char > 'z' {
+			return false
+		}
+	}
+	return true
+}

internal/cli/app.go

@@ -42,6 +42,7 @@ import (
 	"github.com/Gitlawb/zero/internal/worktrees"
 	"github.com/Gitlawb/zero/internal/zerogit"
 	"github.com/Gitlawb/zero/internal/zeroruntime"
+	"github.com/charmbracelet/x/term"
 )
 
 var version = "dev"
@@ -339,7 +340,17 @@ func runWithDeps(args []string, stdout io.Writer, stderr io.Writer, deps appDeps
 				return 0
 			}
 		}
-		if _, err := fmt.Fprintf(stdout, "zero %s\n", version); err != nil {
+		// Pipes and redirects keep the machine-readable contract exactly as it
+		// was: a single "zero <version>" line. Scripts, command substitutions,
+		// and the NPM wrapper smoke check all parse that record, so the banner
+		// is strictly a TTY affordance.
+		if !stdoutIsTerminal(stdout) {
+			if _, err := fmt.Fprintf(stdout, "zero %s\n", version); err != nil {
+				return 1
+			}
+			return 0
+		}
+		if _, err := fmt.Fprintf(stdout, "%s\n\nzero %s\n", tui.Wordmark(), version); err != nil {
 			return 1
 		}
 		return 0
@@ -755,11 +766,12 @@ func runInteractiveTUIWithSetup(stderr io.Writer, deps appDeps, permissionMode a
 	}
 	sandboxBackend := deps.selectSandboxBackend(sandbox.BackendOptions{})
 	sandboxEngine := sandbox.NewEngine(sandbox.EngineOptions{
-		WorkspaceRoot: workspaceRoot,
-		Policy:        applyConfiguredSandboxPolicy(sandbox.DefaultPolicy(), resolved.Sandbox),
-		Store:         sandboxStore,
-		Backend:       sandboxBackend,
-		Scope:         scope,
+		WorkspaceRoot:    workspaceRoot,
+		Policy:           applyConfiguredSandboxPolicy(sandbox.DefaultPolicy(), resolved.Sandbox),
+		Store:            sandboxStore,
+		Backend:          sandboxBackend,
+		Scope:            scope,
+		SensitiveEnvKeys: providerSensitiveEnvKeys(resolved),
 	})
 	lastKnownMCPConfig := mcpConfig
 	fileTracker := tools.NewFileTracker()
@@ -1115,6 +1127,17 @@ func closeSpecialistRuntime(stderr io.Writer, runtime *agentToolRuntime) {
 	}
 }
 
+// stdoutIsTerminal reports whether w is an interactive terminal. Tests pass
+// bytes.Buffer writers and pipes/redirects fail term.IsTerminal, so both take
+// the machine-readable path.
+func stdoutIsTerminal(w io.Writer) bool {
+	f, ok := w.(*os.File)
+	if !ok {
+		return false
+	}
+	return term.IsTerminal(f.Fd())
+}
+
 func writeAppError(stderr io.Writer, message string, exitCode int) int {
 	if _, err := fmt.Fprintf(stderr, "[zero] %s\n", message); err != nil {
 		return 1
@@ -1318,6 +1341,9 @@ Flags:
       --spec-reasoning-effort <effort>
                                     Override draft reasoning effort when --use-spec is set
       --max-turns <number>           Override the maximum agent loop turns
+      --exec-profile <name>          Apply an execution profile (balanced, fast, thorough): loop
+                                    posture only (turn budget, effort, self-correction, escalation);
+                                    composes with --mode (which picks the model) and explicit flags win
       --auto <low|medium|high>       Set exec autonomy; high enables unsafe tools
       --enabled-tools <tools>        Only expose these comma or space separated tools
       --disabled-tools <tools>       Hide these comma or space separated tools

internal/cli/app_test.go

@@ -41,6 +41,8 @@ func TestRunPrintsVersion(t *testing.T) {
 	if exitCode != 0 {
 		t.Fatalf("expected exit code 0, got %d", exitCode)
 	}
+	// Non-terminal stdout keeps the machine-readable contract: exactly one
+	// "zero <version>" record, no wordmark banner, no ANSI.
 	if got := stdout.String(); got != "zero dev\n" {
 		t.Fatalf("expected version output, got %q", got)
 	}
@@ -49,6 +51,33 @@ func TestRunPrintsVersion(t *testing.T) {
 	}
 }
 
+// TestRunVersionRedirectedFile covers the `zero --version > file` path: stdout
+// is a real *os.File but not a terminal, so the single-line contract must hold.
+func TestRunVersionRedirectedFile(t *testing.T) {
+	stdout, err := os.CreateTemp(t.TempDir(), "version-stdout")
+	if err != nil {
+		t.Fatalf("create temp stdout: %v", err)
+	}
+	defer stdout.Close()
+	var stderr bytes.Buffer
+
+	exitCode := Run([]string{"--version"}, stdout, &stderr)
+
+	if exitCode != 0 {
+		t.Fatalf("expected exit code 0, got %d", exitCode)
+	}
+	content, err := os.ReadFile(stdout.Name())
+	if err != nil {
+		t.Fatalf("read temp stdout: %v", err)
+	}
+	if got := string(content); got != "zero dev\n" {
+		t.Fatalf("expected version output, got %q", got)
+	}
+	if stderr.Len() != 0 {
+		t.Fatalf("expected empty stderr, got %q", stderr.String())
+	}
+}
+
 func TestRunPrintsHelp(t *testing.T) {
 	for _, args := range [][]string{
 		{"--help"},

internal/cli/command_center_test.go

@@ -348,6 +348,83 @@ func TestRunProvidersAddWritesCatalogProfile(t *testing.T) {
 	}
 }
 
+func TestRunProvidersAddAimlapiWritesDefaultHeaders(t *testing.T) {
+	var stdout bytes.Buffer
+	var stderr bytes.Buffer
+	configPath := filepath.Join(t.TempDir(), "zero", "config.json")
+
+	exitCode := runWithDeps([]string{"providers", "add", "aimlapi"}, &stdout, &stderr, providerSetupDeps(configPath))
+
+	if exitCode != exitSuccess {
+		t.Fatalf("expected exit code %d, got %d: %s", exitSuccess, exitCode, stderr.String())
+	}
+	cfg := readFileConfig(t, configPath)
+	if len(cfg.Providers) != 1 {
+		t.Fatalf("providers = %#v, want one provider", cfg.Providers)
+	}
+	profile := cfg.Providers[0]
+	if profile.Name != "aimlapi" ||
+		profile.CatalogID != "aimlapi" ||
+		profile.BaseURL != "https://api.aimlapi.com/v1" ||
+		profile.Model != "anthropic/claude-sonnet-5" ||
+		profile.APIKeyEnv != "AIMLAPI_API_KEY" {
+		t.Fatalf("unexpected provider profile: %#v", profile)
+	}
+	if profile.CustomHeaders["X-AIMLAPI-Partner-ID"] != "part_62yQoGYDq4Yqnrj2R1iGrDNJ" ||
+		profile.CustomHeaders["X-AIMLAPI-Integration-Repo"] != "Gitlawb/zero" {
+		t.Fatalf("missing aimlapi.com default headers: %#v", profile.CustomHeaders)
+	}
+}
+
+func TestRunProvidersAddAimlapiMixedCaseHeaderOverride(t *testing.T) {
+	var stdout bytes.Buffer
+	var stderr bytes.Buffer
+	configPath := filepath.Join(t.TempDir(), "zero", "config.json")
+
+	// A differently-cased override must replace the catalog header in place, not
+	// leave both spellings behind to race when request construction canonicalizes.
+	exitCode := runWithDeps([]string{
+		"providers", "add", "aimlapi",
+		"--header", "x-aimlapi-partner-id=part_override",
+	}, &stdout, &stderr, providerSetupDeps(configPath))
+
+	if exitCode != exitSuccess {
+		t.Fatalf("expected exit code %d, got %d: %s", exitSuccess, exitCode, stderr.String())
+	}
+	profile := readFileConfig(t, configPath).Providers[0]
+	if _, ok := profile.CustomHeaders["x-aimlapi-partner-id"]; ok {
+		t.Fatalf("lowercase override left a duplicate key: %#v", profile.CustomHeaders)
+	}
+	if profile.CustomHeaders["X-AIMLAPI-Partner-ID"] != "part_override" {
+		t.Fatalf("override did not win on the canonical key: %#v", profile.CustomHeaders)
+	}
+}
+
+func TestRunProvidersAddAimlapiOverrideDropsCatalogHeaders(t *testing.T) {
+	var stdout bytes.Buffer
+	var stderr bytes.Buffer
+	configPath := filepath.Join(t.TempDir(), "zero", "config.json")
+
+	exitCode := runWithDeps([]string{
+		"providers", "add", "aimlapi",
+		"--base-url", "https://staging.example/v1",
+		"--header", "X-Environment=staging",
+	}, &stdout, &stderr, providerSetupDeps(configPath))
+	if exitCode != exitSuccess {
+		t.Fatalf("expected exit code %d, got %d: %s", exitSuccess, exitCode, stderr.String())
+	}
+	profile := readFileConfig(t, configPath).Providers[0]
+	if _, ok := profile.CustomHeaders["X-AIMLAPI-Partner-ID"]; ok {
+		t.Fatalf("partner attribution leaked to overridden endpoint: %#v", profile.CustomHeaders)
+	}
+	if _, ok := profile.CustomHeaders["X-AIMLAPI-Integration-Repo"]; ok {
+		t.Fatalf("integration attribution leaked to overridden endpoint: %#v", profile.CustomHeaders)
+	}
+	if profile.CustomHeaders["X-Environment"] != "staging" {
+		t.Fatalf("explicit user header was dropped: %#v", profile.CustomHeaders)
+	}
+}
+
 func TestRunProvidersAddWritesCustomHeaders(t *testing.T) {
 	var stdout bytes.Buffer
 	var stderr bytes.Buffer

internal/cli/distribution.go

@@ -118,7 +118,8 @@ func runSkillInfo(args []string, dir string, stdout io.Writer, stderr io.Writer)
 	if name == "" {
 		return writeExecUsageError(stderr, "usage: zero skill info <name> [--json]")
 	}
-	info, ok := skills.Info(dir, name)
+	// Resolve across primary + ~/.agents/skills; lock metadata only from primary.
+	info, ok := skills.InfoFromRoots(dir, skills.GlobalRoots(dir), name)
 	if !ok {
 		return writeAppError(stderr, fmt.Sprintf("skill %q not found", name), exitUsage)
 	}

internal/cli/exec.go

@@ -13,6 +13,7 @@ import (
 	"github.com/Gitlawb/zero/internal/agent"
 	"github.com/Gitlawb/zero/internal/config"
 	"github.com/Gitlawb/zero/internal/errhint"
+	"github.com/Gitlawb/zero/internal/execprofile"
 	"github.com/Gitlawb/zero/internal/imageinput"
 	"github.com/Gitlawb/zero/internal/lsp"
 	"github.com/Gitlawb/zero/internal/modelregistry"
@@ -25,6 +26,7 @@ import (
 	"github.com/Gitlawb/zero/internal/specmode"
 	"github.com/Gitlawb/zero/internal/streamjson"
 	"github.com/Gitlawb/zero/internal/tools"
+	"github.com/Gitlawb/zero/internal/trace"
 	"github.com/Gitlawb/zero/internal/usage"
 	"github.com/Gitlawb/zero/internal/worktrees"
 	"github.com/Gitlawb/zero/internal/zeroruntime"
@@ -68,7 +70,14 @@ type execOptions struct {
 	// intentionally inert: nothing consumes it. Model selection is driven by
 	// --model / --mode instead. See writeExecHelp ("Accept legacy model profile
 	// selection") and TestRunExecAcceptsLegacyModelProfileFlags.
-	modelProfile          string
+	modelProfile string
+	// execProfile selects a named execution profile (balanced, fast, thorough):
+	// a loop-posture bundle (turn budget, reasoning effort, self-correction,
+	// escalation triggers) applied AFTER --mode with the same
+	// fill-only-if-unset rule, so precedence is explicit flag > mode > profile.
+	// Distinct from the mode preset also named "fast" (which picks a model) and
+	// from the legacy inert --profile above. See internal/execprofile.
+	execProfile           string
 	reasoningEffort       string
 	useSpec               bool
 	specModel             string
@@ -124,6 +133,12 @@ type execOptions struct {
 	// additional write roots for this run. Unioned with
 	// config.SandboxConfig.AdditionalWriteRoots at scope construction time.
 	addDirs []string
+	// tracePath, when set, writes a per-turn NDJSON trace (agenteval-compatible)
+	// to the given file path — or to stderr when the value is "-". Falls back to
+	// the ZERO_TRACE env var when the flag is absent. Off by default: a run
+	// without it leaves agent.Options.Trace nil and is byte-identical to before.
+	// The trace is pure observation — enabling it does not change agent behavior.
+	tracePath string
 }
 
 type execUsageError struct {
@@ -160,6 +175,14 @@ func runExec(args []string, stdout io.Writer, stderr io.Writer, deps appDeps) in
 	if err := applyExecMode(&options); err != nil {
 		return writeExecFormatUsageError(stdout, stderr, options.outputFormat, err.Error())
 	}
+	// A profile tunes loop posture the way a mode tunes model selection, and
+	// runs after it so the mode's fills count as "set" and win. MaxTurns is
+	// deferred to config resolution below, where the displaced resolved budget
+	// is known and becomes the escalation restore target.
+	execProfile, execProfileFilledEffort, err := applyExecProfile(&options)
+	if err != nil {
+		return writeExecFormatUsageError(stdout, stderr, options.outputFormat, err.Error())
+	}
 
 	workspaceRoot, err := resolveWorkspaceRoot(options.cwd, deps)
 	if err != nil {
@@ -265,6 +288,8 @@ func runExec(args []string, stdout io.Writer, stderr io.Writer, deps appDeps) in
 		}
 		return writeExecProviderError(stdout, stderr, options.outputFormat, "provider_error", err.Error())
 	}
+	var displacedMaxTurns int
+	resolved.MaxTurns, displacedMaxTurns = applyProfileTurnBudget(execProfile, options.maxTurns, resolved.MaxTurns)
 	registerLocalControlTools(registry, workspaceRoot, resolved.LocalControl)
 	if err := validateExecToolFilters(options, registry); err != nil {
 		return writeExecFormatUsageError(stdout, stderr, options.outputFormat, err.Error())
@@ -405,6 +430,36 @@ func runExec(args []string, stdout io.Writer, stderr io.Writer, deps appDeps) in
 		}
 	}
 
+	// Optimized OpenAI turn sessions (ZERO_OPENAI_TURN_SESSION, default off).
+	// nil when gated off or the profile is ineligible: agent.Run then wraps the
+	// provider in its default adapter — the exact code path of today. The
+	// session switcher is installed only when the run START is optimized, so
+	// the legacy ModelSwitcher path above stays untouched otherwise.
+	turnSessions, _ := providers.OptimizedTurnSessions(resolved.Provider, provider, providers.Options{})
+	var modelSessionSwitcher func(context.Context, string) (zeroruntime.TurnSessionProvider, error)
+	if options.allowEscalation && turnSessions != nil {
+		modelSessionSwitcher = func(_ context.Context, modelID string) (zeroruntime.TurnSessionProvider, error) {
+			switchedProfile := resolved.Provider
+			switchedProfile.Model = modelID
+			switchedProvider, err := deps.newProvider(switchedProfile)
+			if err != nil {
+				return nil, err
+			}
+			if switchedProvider == nil {
+				// The loop treats a nil session source as "no swap" — mirror the
+				// legacy closure's (nil, nil) contract.
+				return nil, nil
+			}
+			currentModel = modelID
+			if optimized, ok := providers.OptimizedTurnSessions(switchedProfile, switchedProvider, providers.Options{}); ok {
+				return optimized, nil
+			}
+			// Ineligible switch target: default adapter, but with the switched
+			// model's resolved capability projection preserved.
+			return providers.DefaultTurnSessions(switchedProfile, switchedProvider, providers.Options{}), nil
+		}
+	}
+
 	runMetadata, err := resolveExecRunMetadata(resolved.Provider)
 	if err != nil {
 		return writeExecProviderError(stdout, stderr, options.outputFormat, "provider_error", err.Error())
@@ -422,6 +477,12 @@ func runExec(args []string, stdout io.Writer, stderr io.Writer, deps appDeps) in
 	notify.MaybeAddWebhookSink(notifier, os.Getenv, func(format string, args ...any) {
 		fmt.Fprintf(stderr, "[notify] "+format+"\n", args...)
 	})
+	// Spec-draft runs synthesize a prompt offline and never drive a model turn, so
+	// there is no per-turn trace to emit. Reject --trace / ZERO_TRACE up front with
+	// a clear error rather than silently accepting and writing nothing.
+	if options.useSpec && resolveTracePath(options) != "" {
+		return writeExecFormatUsageError(stdout, stderr, options.outputFormat, "--trace / ZERO_TRACE are not supported for spec-draft runs")
+	}
 	if options.useSpec {
 		return runExecSpecDraft(execSpecDraftRun{
 			options:            options,
@@ -443,6 +504,13 @@ func runExec(args []string, stdout io.Writer, stderr io.Writer, deps appDeps) in
 			reasoningEffort:    forwardEffort,
 			specPermissionMode: permissionMode,
 			notifier:           notifier,
+			// The profile displaced resolved.MaxTurns above, so the spec-draft
+			// run arms the same escalation policy as the main run (in practice
+			// only the failure-streak and risky-mutation triggers can fire
+			// here: the draft runs without the completion gate or a
+			// self-corrector).
+			profilePolicy: execProfile.Policy(displacedMaxTurns,
+				specProfileEffortFilled(execProfileFilledEffort, options.specReasoningEffort)),
 		})
 	}
 
@@ -474,6 +542,24 @@ func runExec(args []string, stdout io.Writer, stderr io.Writer, deps appDeps) in
 	if err != nil {
 		return writeAppError(stderr, "failed to create run id: "+err.Error(), exitCrash)
 	}
+	// Per-turn tracing is opt-in (--trace <path> or ZERO_TRACE=<path>). The
+	// recorder is stamped throughout agent.Run and the providerio seam; the run
+	// itself is byte-identical to an untraced run. We finish the recorder at the
+	// agent.Run boundary (below) so the snapshot captures exactly one turn, then
+	// serialize the snapshot on every exit path via the defer. "-" writes NDJSON
+	// to stderr; otherwise the path is created/truncated. A failure to emit is
+	// logged to stderr, never fatal.
+	tracePath := resolveTracePath(options)
+	var traceRecorder *trace.Recorder
+	var traceSnapshot *trace.TurnTrace
+	if tracePath != "" {
+		traceRecorder = trace.NewRecorder(preparedSession.Session.SessionID, runID, execProfile.Name)
+		defer func() {
+			if err := writeTraceSnapshot(traceSnapshot, tracePath, stderr); err != nil {
+				fmt.Fprintf(stderr, "[zero] failed to write trace: %s\n", err)
+			}
+		}()
+	}
 	writer := execEventWriter{
 		stdout:       stdout,
 		stderr:       stderr,
@@ -541,28 +627,32 @@ func runExec(args []string, stdout io.Writer, stderr io.Writer, deps appDeps) in
 	hookDispatcher, hookSkip := newHookDispatcherWithExtra(workspaceRoot, pluginActivation.hooks, trustRoot)
 	emitTrustNotice(stderr, hookSkip, pluginActivation.trustSkip, mcpSkip)
 	result, err := agent.Run(runCtx, agentPrompt, provider, agent.Options{
-		MaxTurns:         resolved.MaxTurns,
-		ContextWindow:    resolveAgentContextWindow(runCtx, modelRegistry, resolved.Provider),
-		DeferThreshold:   effectiveDeferThreshold,
-		Specialists:      specialistRuntime.specialistInfos(),
-		Skills:           pluginActivation.skillInfos(deps.skillsDir()),
-		SessionID:        preparedSession.Session.SessionID,
-		CallingSessionID: options.callingSessionID,
-		CallingToolUseID: options.callingToolUseID,
-		Tag:              options.tag,
-		Depth:            options.depth,
-		SessionTitle:     sessionTitle,
-		ProviderName:     resolved.Provider.Name,
-		Model:            resolved.Provider.Model,
-		ModelSwitcher:    modelSwitcher,
-		ReasoningEffort:  forwardEffort,
-		Cwd:              workspaceRoot,
-		Images:           images,
-		Registry:         registry,
-		PermissionMode:   permissionMode,
-		Autonomy:         options.autonomy,
-		SelfCorrect:      selfCorrector,
-		FileDiagnostics:  fileDiagnostics,
+		MaxTurns:             resolved.MaxTurns,
+		ContextWindow:        resolveAgentContextWindow(runCtx, modelRegistry, resolved.Provider),
+		DeferThreshold:       effectiveDeferThreshold,
+		Specialists:          specialistRuntime.specialistInfos(),
+		Skills:               pluginActivation.skillInfos(deps.skillsDir()),
+		SessionID:            preparedSession.Session.SessionID,
+		CallingSessionID:     options.callingSessionID,
+		CallingToolUseID:     options.callingToolUseID,
+		Tag:                  options.tag,
+		Depth:                options.depth,
+		SessionTitle:         sessionTitle,
+		ProviderName:         resolved.Provider.Name,
+		Model:                resolved.Provider.Model,
+		ModelSwitcher:        modelSwitcher,
+		TurnSessionProvider:  turnSessions,
+		ModelSessionSwitcher: modelSessionSwitcher,
+		ReasoningEffort:      forwardEffort,
+		Trace:                traceRecorder,
+		Cwd:                  workspaceRoot,
+		Images:               images,
+		Registry:             registry,
+		PermissionMode:       permissionMode,
+		Autonomy:             options.autonomy,
+		SelfCorrect:          selfCorrector,
+		FileDiagnostics:      fileDiagnostics,
+		Profile:              execProfile.Policy(displacedMaxTurns, execProfileFilledEffort),
 		// Headless exec: don't accept a no-tool-call turn as "done" while work
 		// clearly remains (pending plan items / a mid-step continuation cue) —
 		// nudge to continue, and finalize as INCOMPLETE rather than false success
@@ -604,6 +694,9 @@ func runExec(args []string, stdout io.Writer, stderr io.Writer, deps appDeps) in
 			if len(result.Meta) > 0 {
 				payload["meta"] = result.Meta
 			}
+			if result.Truncated {
+				payload["truncated"] = true
+			}
 			if result.Redacted {
 				payload["redacted"] = true
 			}
@@ -625,6 +718,12 @@ func runExec(args []string, stdout io.Writer, stderr io.Writer, deps appDeps) in
 			sessionRecorder.append(sessions.EventUsage, payload)
 		},
 	})
+	// Finish the trace now that the turn is done, so the snapshot captures exactly
+	// agent.Run's work and nothing the post-run cleanup stamps. The deferred
+	// writer serializes the snapshot on every exit path.
+	if traceRecorder != nil {
+		traceSnapshot = traceRecorder.Finish()
+	}
 	notifier.Notify(notify.Completion, notify.DefaultMessage(notify.Completion))
 	if writer.err != nil {
 		return exitCrash
@@ -815,17 +914,37 @@ func buildExecSandboxEngine(workspaceRoot string, resolved config.ResolvedConfig
 	policy := applyConfiguredSandboxPolicy(sandbox.DefaultPolicy(), resolved.Sandbox)
 	backend := deps.selectSandboxBackend(sandbox.BackendOptions{})
 	return sandbox.NewEngine(sandbox.EngineOptions{
-		WorkspaceRoot: workspaceRoot,
-		Policy:        policy,
-		Store:         store,
-		Backend:       backend,
-		Scope:         scope,
+		WorkspaceRoot:    workspaceRoot,
+		Policy:           policy,
+		Store:            store,
+		Backend:          backend,
+		Scope:            scope,
+		SensitiveEnvKeys: providerSensitiveEnvKeys(resolved),
 	}), nil
 }
 
+func providerSensitiveEnvKeys(resolved config.ResolvedConfig) []string {
+	keys := make([]string, 0, len(resolved.Providers)+1)
+	for _, profile := range resolved.Providers {
+		if key := strings.TrimSpace(profile.APIKeyEnv); key != "" {
+			keys = append(keys, key)
+		}
+	}
+	if key := strings.TrimSpace(resolved.Provider.APIKeyEnv); key != "" {
+		keys = append(keys, key)
+	}
+	return keys
+}
+
 // applyConfiguredSandboxPolicy overlays every config-sourced sandbox knob onto
 // the default policy.
 func applyConfiguredSandboxPolicy(policy sandbox.Policy, cfg config.SandboxConfig) sandbox.Policy {
+	// An explicit `"sandbox": {"enabled": false}` disables the sandbox: every
+	// request is allowed and commands run unwrapped. Only reachable from global
+	// config / CLI — project config never sets Enabled (see mergeProjectConfig).
+	if cfg.Enabled != nil && !*cfg.Enabled {
+		policy.Mode = sandbox.ModeDisabled
+	}
 	if network := strings.TrimSpace(cfg.Network); network != "" {
 		switch sandbox.NetworkMode(network) {
 		case sandbox.NetworkAllow, sandbox.NetworkDeny:
@@ -1046,6 +1165,67 @@ func applyExecMode(options *execOptions) error {
 	return nil
 }
 
+// applyExecProfile expands an --exec-profile selection onto the exec options.
+// Like applyExecMode it only fills fields the caller left unset, and it runs
+// AFTER the mode so a mode-filled field counts as set: precedence is explicit
+// flag > --mode > --exec-profile. Only the options-level knobs are applied here
+// (reasoning effort still flows through the model-supported gating downstream;
+// self-correct is presence-only so a profile can only turn it on). MaxTurns is
+// intentionally NOT applied here — the profile displaces the resolved budget
+// after config resolution, where the displaced value is known and becomes the
+// escalation restore target. An unknown profile is a usage error listing the
+// valid names. Not to be confused with the legacy inert --profile flag.
+// The second return reports whether the profile actually filled the reasoning
+// effort (false when the user set one explicitly), so the escalation policy
+// knows the displaced effort was the provider default and can restore it.
+func applyExecProfile(options *execOptions) (execprofile.Profile, bool, error) {
+	name := strings.TrimSpace(options.execProfile)
+	if name == "" {
+		return execprofile.Profile{}, false, nil
+	}
+	profile, ok := execprofile.Lookup(name)
+	if !ok {
+		return execprofile.Profile{}, false, execUsageError{fmt.Sprintf("unknown execution profile %q. Valid profiles: %s.", options.execProfile, strings.Join(execprofile.Names(), ", "))}
+	}
+	effortFilled := false
+	if options.reasoningEffort == "" && profile.ReasoningEffort != "" {
+		options.reasoningEffort = profile.ReasoningEffort
+		effortFilled = true
+	}
+	// Spec-safe projection: the spec-draft path wires no self-corrector (an
+	// explicit --self-correct --use-spec is rejected at parse time, before
+	// profiles apply), so a profile's self-correct knob is meaningless there.
+	// Project it away rather than erroring: the user asked for a thorough
+	// DRAFT, and the profile's other knobs (budget, effort) apply to it fine.
+	if profile.SelfCorrect && !options.useSpec {
+		options.selfCorrect = true
+	}
+	return profile, effortFilled, nil
+}
+
+// specProfileEffortFilled reports whether the profile's effort fill actually
+// governs the spec-draft run. An explicit --spec-reasoning-effort replaces the
+// filled effort for the draft, so the escalation's effort restore must not arm
+// there: escalation must never clear an effort the user pinned by hand.
+func specProfileEffortFilled(effortFilled bool, specReasoningEffort string) bool {
+	return effortFilled && strings.TrimSpace(specReasoningEffort) == ""
+}
+
+// applyProfileTurnBudget decides the run's turn budget once config is resolved.
+// The profile displaces the RESOLVED value, not the flag: a pinned budget
+// always wins and the profile backs off entirely, while an env/config budget
+// is the "balanced posture" a mid-run escalation can restore. pinnedMaxTurns
+// is any caller-pinned budget — an explicit --max-turns flag OR a mode
+// preset's fill (both land in options.maxTurns, and a mode outranks a profile
+// just like the flag does). displaced is 0 when nothing was displaced, so an
+// escalation leaves the ceiling untouched.
+func applyProfileTurnBudget(profile execprofile.Profile, pinnedMaxTurns int, resolvedMaxTurns int) (effective int, displaced int) {
+	if profile.MaxTurns > 0 && pinnedMaxTurns == 0 {
+		return profile.MaxTurns, resolvedMaxTurns
+	}
+	return resolvedMaxTurns, 0
+}
+
 // resolveSelectedModel routes a user-supplied --model value through the model
 // registry so that fuzzy aliases (e.g. "sonnet 4.5") resolve to canonical ids
 // and deprecated models auto-redirect to their fallback. It returns the model id
@@ -1237,3 +1417,36 @@ func execNotifyMode(options execOptions, resolved config.ResolvedConfig) string
 	}
 	return resolved.Notify.Mode
 }
+
+// resolveTracePath returns the trace destination for this run: the --trace flag
+// value when set, else the ZERO_TRACE env var, else "" (tracing off). A value of
+// "-" means "write to stderr".
+func resolveTracePath(options execOptions) string {
+	if v := strings.TrimSpace(options.tracePath); v != "" {
+		return v
+	}
+	if v := strings.TrimSpace(os.Getenv("ZERO_TRACE")); v != "" {
+		return v
+	}
+	return ""
+}
+
+// writeTraceSnapshot writes an already-finished trace snapshot to dest ("-" =>
+// stderr, otherwise a file path created/truncated). A nil snapshot is a no-op
+// (tracing off, or the run exited before agent.Run produced a turn). The trace
+// is best-effort: a write error is returned to the caller, which logs it but
+// never fails the run.
+func writeTraceSnapshot(snapshot *trace.TurnTrace, dest string, stderr io.Writer) error {
+	if snapshot == nil || dest == "" {
+		return nil
+	}
+	if strings.TrimSpace(dest) == "-" {
+		return trace.WriteNDJSON(stderr, snapshot)
+	}
+	file, err := os.Create(dest)
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+	return trace.WriteNDJSON(file, snapshot)
+}

internal/cli/exec_parse.go

@@ -32,6 +32,15 @@ func parseExecArgs(args []string) (execOptions, bool, error) {
 			options.noNotify = true
 		case arg == "--no-completion-gate":
 			options.noCompletionGate = true
+		case arg == "--trace":
+			value, next, err := nextFlagValue(args, index, arg)
+			if err != nil {
+				return options, false, err
+			}
+			options.tracePath = value
+			index = next
+		case strings.HasPrefix(arg, "--trace="):
+			options.tracePath = strings.TrimSpace(strings.TrimPrefix(arg, "--trace="))
 		case arg == "--notify":
 			value, next, err := nextFlagValue(args, index, arg)
 			if err != nil {
@@ -138,6 +147,19 @@ func parseExecArgs(args []string) (execOptions, bool, error) {
 			index = next
 		case strings.HasPrefix(arg, "--profile="):
 			options.modelProfile = strings.TrimSpace(strings.TrimPrefix(arg, "--profile="))
+		case arg == "--exec-profile":
+			value, next, err := nextFlagValue(args, index, arg)
+			if err != nil {
+				return options, false, err
+			}
+			options.execProfile = strings.TrimSpace(value)
+			index = next
+		case strings.HasPrefix(arg, "--exec-profile="):
+			value, err := requiredInlineFlagValue(arg, "--exec-profile")
+			if err != nil {
+				return options, false, err
+			}
+			options.execProfile = value
 		case arg == "-r" || arg == "--reasoning-effort":
 			value, next, err := nextFlagValue(args, index, arg)
 			if err != nil {

internal/cli/exec_profile_test.go

@@ -0,0 +1,224 @@
+package cli
+
+import (
+	"os"
+	"path/filepath"
+	"reflect"
+	"strings"
+	"testing"
+
+	"github.com/Gitlawb/zero/internal/execprofile"
+)
+
+func TestApplyExecProfileFillsOnlyUnset(t *testing.T) {
+	// Unset effort: the profile fills it and reports the fill, so the
+	// escalation policy knows the displaced effort was the provider default.
+	options := execOptions{execProfile: "fast"}
+	profile, effortFilled, err := applyExecProfile(&options)
+	if err != nil {
+		t.Fatalf("applyExecProfile: %v", err)
+	}
+	if profile.Name != "fast" {
+		t.Fatalf("profile.Name = %q, want fast", profile.Name)
+	}
+	if options.reasoningEffort != "low" {
+		t.Fatalf("reasoningEffort = %q, want the profile's low", options.reasoningEffort)
+	}
+	if !effortFilled {
+		t.Fatal("the profile filled the effort, so effortFilled must report it")
+	}
+
+	// Set effort (explicit flag or a mode's fill): the profile backs off.
+	options = execOptions{execProfile: "fast", reasoningEffort: "high"}
+	_, effortFilled, err = applyExecProfile(&options)
+	if err != nil {
+		t.Fatalf("applyExecProfile: %v", err)
+	}
+	if options.reasoningEffort != "high" {
+		t.Fatalf("reasoningEffort = %q, an explicit value must win over the profile", options.reasoningEffort)
+	}
+	if effortFilled {
+		t.Fatal("the profile backed off, so effortFilled must be false")
+	}
+}
+
+func TestApplyExecProfileThoroughArmsSelfCorrect(t *testing.T) {
+	options := execOptions{execProfile: "thorough"}
+	if _, _, err := applyExecProfile(&options); err != nil {
+		t.Fatalf("applyExecProfile: %v", err)
+	}
+	if !options.selfCorrect {
+		t.Fatal("thorough must arm the post-edit self-correct loop")
+	}
+	if options.reasoningEffort != "high" {
+		t.Fatalf("reasoningEffort = %q, want high", options.reasoningEffort)
+	}
+}
+
+// The spec-draft path wires no self-corrector (explicit --self-correct
+// --use-spec is rejected at parse time, before profiles apply), so a profile's
+// self-correct knob is projected away under --use-spec instead of silently
+// arming a knob the draft runner ignores. The other knobs still apply.
+func TestApplyExecProfileSpecProjectsAwaySelfCorrect(t *testing.T) {
+	options := execOptions{execProfile: "thorough", useSpec: true}
+	if _, _, err := applyExecProfile(&options); err != nil {
+		t.Fatalf("applyExecProfile: %v", err)
+	}
+	if options.selfCorrect {
+		t.Fatal("thorough under --use-spec must not arm self-correct (the draft runner has none)")
+	}
+	if options.reasoningEffort != "high" {
+		t.Fatalf("reasoningEffort = %q, the profile's other knobs must still apply", options.reasoningEffort)
+	}
+}
+
+func TestApplyExecProfileUnknownIsUsageError(t *testing.T) {
+	options := execOptions{execProfile: "turbo"}
+	_, _, err := applyExecProfile(&options)
+	if err == nil {
+		t.Fatal("expected a usage error for an unknown profile")
+	}
+	if _, ok := err.(execUsageError); !ok {
+		t.Fatalf("expected execUsageError, got %T: %v", err, err)
+	}
+	for _, name := range execprofile.Names() {
+		if !strings.Contains(err.Error(), name) {
+			t.Fatalf("usage error must list %q, got %q", name, err.Error())
+		}
+	}
+}
+
+// Precedence: explicit flag > --mode > --exec-profile. The deep mode fills
+// effort=high and max-turns=160; the fast profile must not override either,
+// because a mode-filled field counts as set by the time the profile runs.
+func TestExecProfilePrecedenceFlagOverModeOverProfile(t *testing.T) {
+	options := execOptions{mode: "deep", execProfile: "fast"}
+	if err := applyExecMode(&options); err != nil {
+		t.Fatalf("applyExecMode: %v", err)
+	}
+	profile, _, err := applyExecProfile(&options)
+	if err != nil {
+		t.Fatalf("applyExecProfile: %v", err)
+	}
+	if options.reasoningEffort != "high" {
+		t.Fatalf("reasoningEffort = %q, the mode's high must win over the profile's low", options.reasoningEffort)
+	}
+	// The mode filled options.maxTurns, so the turn budget must not be displaced.
+	effective, displaced := applyProfileTurnBudget(profile, options.maxTurns, options.maxTurns)
+	if effective != 160 || displaced != 0 {
+		t.Fatalf("turn budget = (%d, displaced %d), the mode's 160 must win with nothing displaced", effective, displaced)
+	}
+}
+
+func TestApplyProfileTurnBudget(t *testing.T) {
+	fast, _ := execprofile.Lookup("fast")
+	balanced, _ := execprofile.Lookup("balanced")
+
+	// No explicit flag: the profile displaces the resolved budget.
+	if effective, displaced := applyProfileTurnBudget(fast, 0, 80); effective != 30 || displaced != 80 {
+		t.Fatalf("fast over resolved 80 = (%d, %d), want (30, 80)", effective, displaced)
+	}
+	// Explicit --max-turns pins the budget; the profile backs off entirely.
+	if effective, displaced := applyProfileTurnBudget(fast, 50, 50); effective != 50 || displaced != 0 {
+		t.Fatalf("fast with explicit 50 = (%d, %d), want (50, 0)", effective, displaced)
+	}
+	// Balanced never displaces anything.
+	if effective, displaced := applyProfileTurnBudget(balanced, 0, 80); effective != 80 || displaced != 0 {
+		t.Fatalf("balanced over resolved 80 = (%d, %d), want (80, 0)", effective, displaced)
+	}
+}
+
+// The no-regression invariant at the options level: selecting balanced leaves
+// the options byte-identical to not selecting a profile at all, and produces
+// no loop policy.
+func TestExecProfileBalancedLeavesOptionsUntouched(t *testing.T) {
+	options := execOptions{execProfile: "balanced"}
+	reference := options
+	profile, _, err := applyExecProfile(&options)
+	if err != nil {
+		t.Fatalf("applyExecProfile: %v", err)
+	}
+	if !reflect.DeepEqual(options, reference) {
+		t.Fatalf("balanced changed the options: %+v vs %+v", options, reference)
+	}
+	if policy := profile.Policy(80, false); policy != nil {
+		t.Fatalf("balanced must produce a nil policy, got %+v", policy)
+	}
+}
+
+// --exec-profile= with an inline empty value must error like its two-token
+// form and the sibling --mode=, not silently run the default posture (the
+// classic shell hazard: an unset variable expanding into the inline form).
+func TestParseExecProfileInlineEmptyIsError(t *testing.T) {
+	_, _, err := parseExecArgs([]string{"--exec-profile=", "hello"})
+	if err == nil || !strings.Contains(err.Error(), "--exec-profile requires a value") {
+		t.Fatalf("expected a required-value error, got %v", err)
+	}
+}
+
+// Full echo-provider run: the selected profile must be stamped into the
+// per-turn trace so benchmark attribution can group runs by posture.
+func TestRunExecTraceRecordsSelectedProfile(t *testing.T) {
+	tracePath := filepath.Join(t.TempDir(), "trace.ndjson")
+	exitCode, _, stderr := runExecWithEcho(t, []string{
+		"exec", "--exec-profile", "fast", "--trace", tracePath, "hello",
+	})
+	if exitCode != exitSuccess {
+		t.Fatalf("expected exit %d, got %d: %s", exitSuccess, exitCode, stderr)
+	}
+	raw, err := os.ReadFile(tracePath)
+	if err != nil {
+		t.Fatalf("read trace: %v", err)
+	}
+	if !strings.Contains(string(raw), `"profile":"fast"`) {
+		t.Fatalf("trace must record the selected profile, got %s", raw)
+	}
+}
+
+// An explicit --spec-reasoning-effort governs the spec draft's effort, so the
+// escalation effort-restore must not arm there even when the profile filled
+// the (unused) main effort.
+func TestSpecProfileEffortFilled(t *testing.T) {
+	if !specProfileEffortFilled(true, "") {
+		t.Fatal("no explicit spec effort: the profile's fill governs, restore must arm")
+	}
+	if specProfileEffortFilled(true, "high") {
+		t.Fatal("an explicit spec effort must disarm the effort restore")
+	}
+	if specProfileEffortFilled(false, "") {
+		t.Fatal("nothing filled, nothing to restore")
+	}
+}
+
+// The trace label deliberately records the SELECTED profile, balanced
+// included, so captures are self-describing. Run behavior stays identical
+// (balanced fills nothing and arms no policy); the label is the one intended
+// difference in the opt-in trace artifact.
+func TestRunExecTraceRecordsBalancedSelection(t *testing.T) {
+	tracePath := filepath.Join(t.TempDir(), "trace.ndjson")
+	exitCode, _, stderr := runExecWithEcho(t, []string{
+		"exec", "--exec-profile", "balanced", "--trace", tracePath, "hello",
+	})
+	if exitCode != exitSuccess {
+		t.Fatalf("expected exit %d, got %d: %s", exitSuccess, exitCode, stderr)
+	}
+	raw, err := os.ReadFile(tracePath)
+	if err != nil {
+		t.Fatalf("read trace: %v", err)
+	}
+	if !strings.Contains(string(raw), `"profile":"balanced"`) {
+		t.Fatalf("trace must record the balanced selection, got %s", raw)
+	}
+}
+
+func TestRunExecUnknownExecProfileIsUsageError(t *testing.T) {
+	exitCode, _, stderr := runExecWithEcho(t, []string{
+		"exec", "--exec-profile", "turbo", "hello",
+	})
+	if exitCode != exitUsage {
+		t.Fatalf("expected usage exit %d, got %d", exitUsage, exitCode)
+	}
+	if !strings.Contains(stderr, "unknown execution profile") {
+		t.Fatalf("expected an unknown-profile usage error, got %q", stderr)
+	}
+}

internal/cli/exec_sessions.go

@@ -72,8 +72,11 @@ func preflightExecSession(options execOptions) error {
 		if session == nil {
 			return execUsageError{"Zero session not found: " + options.resume}
 		}
+		if !sessions.IsResumableKind(session.SessionKind) {
+			return execUsageError{"Zero session is not resumable: " + options.resume}
+		}
 	case options.resumeLatest:
-		latest, err := store.Latest()
+		latest, err := store.LatestResumable()
 		if err != nil {
 			return err
 		}

internal/cli/exec_sessions_test.go

@@ -0,0 +1,26 @@
+package cli
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/Gitlawb/zero/internal/sessions"
+)
+
+func TestPreflightRejectsSideSessions(t *testing.T) {
+	t.Setenv("XDG_DATA_HOME", t.TempDir())
+	store := sessions.NewStore(sessions.StoreOptions{})
+	if _, err := store.Create(sessions.CreateInput{SessionID: "side", SessionKind: sessions.SessionKindSide}); err != nil {
+		t.Fatalf("create side session: %v", err)
+	}
+
+	err := preflightExecSession(execOptions{resumeLatest: true})
+	if err == nil || !strings.Contains(err.Error(), "No Zero sessions available to resume") {
+		t.Fatalf("preflightExecSession error = %v, want no resumable sessions", err)
+	}
+
+	err = preflightExecSession(execOptions{resume: "side"})
+	if err == nil || !strings.Contains(err.Error(), "Zero session is not resumable: side") {
+		t.Fatalf("explicit side-session preflight error = %v, want non-resumable rejection", err)
+	}
+}

internal/cli/exec_spec.go

@@ -46,6 +46,11 @@ type execSpecDraftRun struct {
 	reasoningEffort    string
 	specPermissionMode agent.PermissionMode
 	notifier           *notify.Notifier
+	// profilePolicy carries the selected execution profile's escalation policy
+	// (nil when none): the profile displaces resolved.MaxTurns before this
+	// path branches off, so the spec-draft run needs the same safety net as
+	// the main run.
+	profilePolicy *agent.ProfilePolicy
 }
 
 type execSpecDraftInfo struct {
@@ -119,6 +124,7 @@ func runExecSpecDraft(run execSpecDraftRun) int {
 		ProviderName:    run.resolved.Provider.Name,
 		Model:           run.resolved.Provider.Model,
 		ReasoningEffort: run.reasoningEffort,
+		Profile:         run.profilePolicy,
 		Cwd:             run.workspaceRoot,
 		SystemPrompt:    specmode.DraftSystemPrompt,
 		Images:          run.images,

internal/cli/exec_test.go

@@ -549,10 +549,14 @@ func TestExecMemberAutoToolListIncludesMutators(t *testing.T) {
 }
 
 func TestRunExecAcceptsLegacyModelProfileFlags(t *testing.T) {
+	// --profile (legacy, inert model profile) and --exec-profile (execution
+	// profile) are distinct flags and must coexist on one invocation.
 	exitCode, stdout, stderr := runExecWithEcho(t, []string{
 		"exec",
 		"--profile",
 		"fast",
+		"--exec-profile",
+		"balanced",
 		"--reasoning-effort",
 		"low",
 		"hello",

internal/cli/exec_turn_session_test.go

@@ -0,0 +1,125 @@
+package cli
+
+import (
+	"bytes"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	"github.com/Gitlawb/zero/internal/config"
+	"github.com/Gitlawb/zero/internal/providers/openai"
+	"github.com/Gitlawb/zero/internal/zeroruntime"
+)
+
+// TestRunExecOptimizedSessionUnderGate proves the end-to-end wiring: with
+// ZERO_OPENAI_TURN_SESSION on and a real official-OpenAI provider, a headless
+// run streams through the optimized session — the server sees the prewarm HEAD
+// probe in addition to the turn's POST.
+func TestRunExecOptimizedSessionUnderGate(t *testing.T) {
+	t.Setenv("XDG_DATA_HOME", t.TempDir())
+	t.Setenv("ZERO_OPENAI_TURN_SESSION", "1")
+	cwd := t.TempDir()
+
+	var heads, posts atomic.Int64
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		switch {
+		case r.Method == http.MethodHead:
+			heads.Add(1)
+			w.WriteHeader(http.StatusMethodNotAllowed)
+		case r.Method == http.MethodPost && strings.HasSuffix(r.URL.Path, "/chat/completions"):
+			posts.Add(1)
+			w.Header().Set("Content-Type", "text/event-stream")
+			_, _ = w.Write([]byte("data: {\"choices\":[{\"delta\":{\"content\":\"done\"}}]}\n\n"))
+			_, _ = w.Write([]byte("data: [DONE]\n\n"))
+		default:
+			w.WriteHeader(http.StatusNotFound)
+		}
+	}))
+	defer server.Close()
+
+	var stdout, stderr bytes.Buffer
+	exitCode := runWithDeps([]string{"exec", "say done"}, &stdout, &stderr, appDeps{
+		getwd: func() (string, error) { return cwd, nil },
+		resolveConfig: func(string, config.Overrides) (config.ResolvedConfig, error) {
+			return config.ResolvedConfig{
+				ActiveProvider: "official-openai",
+				Provider: config.ProviderProfile{
+					Name:         "official-openai",
+					ProviderKind: config.ProviderKindOpenAI,
+					BaseURL:      server.URL,
+					APIKey:       "sk-exec-test",
+					Model:        "pr8-exec-model",
+				},
+			}, nil
+		},
+		newProvider: func(profile config.ProviderProfile) (zeroruntime.Provider, error) {
+			// Pin a keep-alive transport so the probe fires on every platform:
+			// the shared default transport disables keep-alives on macOS, where
+			// the session correctly skips the prewarm.
+			transport := http.DefaultTransport.(*http.Transport).Clone()
+			transport.DisableKeepAlives = false
+			return openai.New(openai.Options{
+				APIKey:     profile.APIKey,
+				BaseURL:    profile.BaseURL,
+				Model:      profile.Model,
+				HTTPClient: &http.Client{Transport: transport},
+			})
+		},
+	})
+	if exitCode != exitSuccess {
+		t.Fatalf("exitCode = %d stdout=%s stderr=%s", exitCode, stdout.String(), stderr.String())
+	}
+	if got := posts.Load(); got < 1 {
+		t.Fatalf("server saw %d chat-completions POSTs, want >= 1", got)
+	}
+	// The prewarm probe is asynchronous; it fires well before the model turn
+	// finishes, but poll rather than assuming scheduling order. The deadline
+	// exceeds the production prewarmTimeout (3s) so a slow probe cannot flake
+	// this assertion.
+	deadline := time.Now().Add(5 * time.Second)
+	for heads.Load() == 0 && time.Now().Before(deadline) {
+		time.Sleep(10 * time.Millisecond)
+	}
+	if got := heads.Load(); got != 1 {
+		t.Fatalf("server saw %d prewarm HEAD probes, want exactly 1", got)
+	}
+}
+
+// TestRunExecGateOnFallsBackForFakeProvider proves fallback safety: with the
+// gate on but a provider that is not the concrete *openai.Provider, the run
+// proceeds on the default path exactly as today.
+func TestRunExecGateOnFallsBackForFakeProvider(t *testing.T) {
+	t.Setenv("XDG_DATA_HOME", t.TempDir())
+	t.Setenv("ZERO_OPENAI_TURN_SESSION", "1")
+	cwd := t.TempDir()
+
+	var builds int
+	var stdout, stderr bytes.Buffer
+	exitCode := runWithDeps([]string{"exec", "--model", "claude-haiku-4.5", "hello"}, &stdout, &stderr, appDeps{
+		getwd: func() (string, error) { return cwd, nil },
+		resolveConfig: func(_ string, overrides config.Overrides) (config.ResolvedConfig, error) {
+			model := "claude-haiku-4.5"
+			if overrides.Provider.Model != "" {
+				model = overrides.Provider.Model
+			}
+			cfg := execResolvedConfig()
+			cfg.Provider.ProviderKind = config.ProviderKindAnthropic
+			cfg.Provider.Model = model
+			cfg.MaxTurns = 3
+			return cfg, nil
+		},
+		newProvider: func(config.ProviderProfile) (zeroruntime.Provider, error) {
+			builds++
+			return &escalatingExecProvider{}, nil
+		},
+	})
+	if exitCode != exitSuccess {
+		t.Fatalf("exitCode = %d stdout=%s stderr=%s", exitCode, stdout.String(), stderr.String())
+	}
+	if builds != 1 {
+		t.Fatalf("newProvider called %d times, want 1 (default path, no optimized session)", builds)
+	}
+}

internal/cli/exec_writer.go

@@ -153,6 +153,9 @@ func (writer *execEventWriter) toolResult(result agent.ToolResult) {
 		if len(result.Meta) > 0 {
 			payload["meta"] = result.Meta
 		}
+		if result.Truncated {
+			payload["truncated"] = true
+		}
 		if result.Redacted {
 			payload["redacted"] = true
 		}
@@ -166,7 +169,8 @@ func (writer *execEventWriter) toolResult(result agent.ToolResult) {
 		return
 	}
 	if writer.format == execOutputStreamJSON {
-		output, truncated := truncateForStreamJSONOutput(result.Output)
+		output, surfaceTruncated := truncateForStreamJSONOutput(result.Output)
+		truncated := result.Truncated || surfaceTruncated
 		event := streamjson.Event{
 			Type:         streamjson.EventToolResult,
 			RunID:        writer.runID,

internal/cli/exec_writer_test.go

@@ -1,8 +1,12 @@
 package cli
 
 import (
+	"bytes"
+	"encoding/json"
+	"strings"
 	"testing"
 
+	"github.com/Gitlawb/zero/internal/agent"
 	"github.com/Gitlawb/zero/internal/tools"
 )
 
@@ -16,3 +20,35 @@ func TestStreamJSONSideEffectReportsNoneForControlTool(t *testing.T) {
 		t.Fatalf("streamJSONSideEffect(escalate_model) = %q, want none", got)
 	}
 }
+
+func TestExecWriterPropagatesToolResultTruncation(t *testing.T) {
+	for _, format := range []execOutputFormat{execOutputJSON, execOutputStreamJSON} {
+		t.Run(string(format), func(t *testing.T) {
+			var stdout, stderr bytes.Buffer
+			writer := execEventWriter{
+				stdout:       &stdout,
+				stderr:       &stderr,
+				format:       format,
+				runID:        "run_budget",
+				streamedText: &strings.Builder{},
+			}
+			writer.toolResult(agent.ToolResult{
+				ToolCallID: "call_budget",
+				Name:       "read_file",
+				Status:     tools.StatusOK,
+				Output:     "bounded output",
+				Truncated:  true,
+			})
+			if writer.err != nil {
+				t.Fatalf("toolResult: %v", writer.err)
+			}
+			var payload map[string]any
+			if err := json.Unmarshal(bytes.TrimSpace(stdout.Bytes()), &payload); err != nil {
+				t.Fatalf("decode output %q: %v", stdout.String(), err)
+			}
+			if payload["truncated"] != true {
+				t.Fatalf("truncated = %#v, want true; payload=%#v", payload["truncated"], payload)
+			}
+		})
+	}
+}

internal/cli/plugin_activate.go

@@ -15,11 +15,11 @@ import (
 
 // pluginActivation holds what plugin activation contributed to a bootstrap so the
 // later dispatcher + skill wiring can consume it: the plugin hook definitions and
-// the plugin skill search roots. The zero value (no plugins) is inert — the
-// dispatcher gets no extra hooks and the skill tool keeps only the default dir.
-// The embedded trustSkip reports whether the project plugin layer was dropped for
-// an untrusted workspace, so the caller can fold it into the single combined
-// trust notice.
+// the plugin skill search roots. The zero value (no plugins) still overlays the
+// multi-root skill tool (primary + ~/.agents/skills) so discovery is identical
+// with or without plugins. The embedded trustSkip reports whether the project
+// plugin layer was dropped for an untrusted workspace, so the caller can fold it
+// into the single combined trust notice.
 type pluginActivation struct {
 	hooks      []hooks.Definition
 	skillRoots []string
@@ -52,6 +52,9 @@ func activatePlugins(workspaceRoot string, registry *tools.Registry, deps appDep
 	loaded, err := deps.loadPlugins(plugins.LoadOptions{Cwd: workspaceRoot, ExcludeProject: excludeProject})
 	if err != nil {
 		writePluginActivationWarning(stderr, "failed to load plugins: "+err.Error())
+		// Still overlay multi-root discovery (primary + agents) so a plugin load
+		// failure cannot hide shared skills.
+		registry.Register(plugins.NewSkillTool(deps.skillsDir(), nil))
 		return pluginActivation{trustSkip: skip}
 	}
 
@@ -67,14 +70,11 @@ func activatePlugins(workspaceRoot string, registry *tools.Registry, deps appDep
 		writePluginActivationWarning(stderr, warning)
 	}
 
-	// Re-register the skill tool to also resolve plugin-declared skills. The core
-	// skill tool only reads the default skills dir; the plugin-aware replacement
-	// merges the default dir with the plugin skill roots (default dir wins a name
-	// clash), so plugin skills appear in the agent's skill list. With no plugin
-	// skill roots this is byte-equivalent to the default skills surface.
-	if len(result.SkillRoots) > 0 {
-		registry.Register(plugins.NewSkillTool(deps.skillsDir(), result.SkillRoots))
-	}
+	// Always overlay the multi-root skill tool so discovery is identical with or
+	// without plugins: primary DefaultDir + optional ~/.agents/skills + plugin
+	// roots (earlier wins). With empty SkillRoots and no agents dir this is
+	// byte-equivalent to the core single-dir skill surface.
+	registry.Register(plugins.NewSkillTool(deps.skillsDir(), result.SkillRoots))
 
 	return pluginActivation{hooks: result.Hooks, skillRoots: result.SkillRoots, trustSkip: skip}
 }
@@ -91,8 +91,8 @@ func projectPluginsDirExists(workspaceRoot string) bool {
 }
 
 // skillInfos resolves the reusable skills the model can load via the skill tool —
-// the default skills dir merged with any plugin skill roots, the same set the
-// plugin-aware skill tool resolves against — as plain data for the agent's system
+// primary dir + optional ~/.agents/skills + plugin skill roots, the same set the
+// multi-root skill tool resolves against — as plain data for the agent's system
 // prompt. It returns nil when no skills are installed, so a skill-less run leaves
 // the prompt byte-identical.
 func (a pluginActivation) skillInfos(defaultDir string) []agent.SkillInfo {

internal/cli/plugin_activate_test.go

@@ -69,6 +69,11 @@ func TestActivatePluginsRegistersToolAndCollectsHooks(t *testing.T) {
 }
 
 func TestActivatePluginsRegistersPluginSkillTool(t *testing.T) {
+	// Isolate host ~/.agents/skills so it cannot interfere with this test.
+	home := t.TempDir()
+	t.Setenv("HOME", home)
+	t.Setenv("USERPROFILE", home)
+
 	pluginDir := t.TempDir()
 	skillDir := filepath.Join(pluginDir, "skills", "demo-skill")
 	if err := os.MkdirAll(skillDir, 0o755); err != nil {
@@ -108,6 +113,42 @@ func TestActivatePluginsRegistersPluginSkillTool(t *testing.T) {
 	}
 }
 
+func TestActivatePluginsAlwaysRegistersMultiRootSkillTool(t *testing.T) {
+	// Even with zero plugins / zero plugin skill roots, activation must overlay
+	// the multi-root skill tool so ~/.agents/skills is loadable on bare runs.
+	home := t.TempDir()
+	t.Setenv("HOME", home)
+	t.Setenv("USERPROFILE", home)
+	agents := filepath.Join(home, ".agents", "skills")
+	if err := os.MkdirAll(agents, 0o755); err != nil {
+		t.Fatal(err)
+	}
+	skillDir := filepath.Join(agents, "agents-skill")
+	if err := os.MkdirAll(skillDir, 0o755); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(filepath.Join(skillDir, "SKILL.md"), []byte("---\nname: agents-skill\n---\nagents body"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	registry := tools.NewRegistry()
+	registry.Register(tools.NewSkillTool(t.TempDir())) // core single-dir tool
+	var stderr bytes.Buffer
+	workspace := t.TempDir()
+	activation := activatePlugins(workspace, registry, fakePluginDeps(t, nil), &stderr, workspace)
+	if len(activation.skillRoots) != 0 {
+		t.Fatalf("expected no plugin skill roots, got %#v", activation.skillRoots)
+	}
+	skillTool, ok := registry.Get("skill")
+	if !ok {
+		t.Fatal("skill tool missing after activation")
+	}
+	res := skillTool.Run(context.Background(), map[string]any{"name": "agents-skill"})
+	if res.Status != tools.StatusOK || !bytes.Contains([]byte(res.Output), []byte("agents body")) {
+		t.Fatalf("agents skill must load with zero plugin roots: %q (%s)", res.Status, res.Output)
+	}
+}
+
 func TestActivatePluginsSurfacesLoadDiagnostics(t *testing.T) {
 	// Load succeeds (no top-level error) but reports a per-plugin diagnostic for a
 	// plugin it had to skip. activatePlugins must forward that diagnostic to stderr

internal/cli/provider_onboarding.go

@@ -53,6 +53,22 @@ func runProvidersUse(args []string, stdout io.Writer, stderr io.Writer, deps app
 	if err != nil {
 		return writeAppError(stderr, err.Error(), exitCrash)
 	}
+	// SetActiveProvider only ever matches profiles persisted in config.json
+	// (see config.ProviderPersisted), but a provider can be visible in
+	// `zero providers list`/the TUI picker purely because Resolve()
+	// synthesized it in-memory from an ambient env var (e.g. OPENAI_API_KEY)
+	// without ever writing a row to disk. Without this check, switching to
+	// that provider by name always fails with a confusing "not found" even
+	// though it is genuinely usable this session (issue #707).
+	persisted, err := config.ProviderPersisted(configPath, options.name)
+	if err != nil {
+		return writeAppError(stderr, err.Error(), exitCrash)
+	}
+	if !persisted {
+		if exit, handled := reportUnpersistedProviderUse(stdout, stderr, deps, options, configPath); handled {
+			return exit
+		}
+	}
 	cfg, err := config.SetActiveProvider(configPath, options.name)
 	if err != nil {
 		return writeAppError(stderr, err.Error(), exitCrash)
@@ -352,6 +368,22 @@ func runProvidersRemove(args []string, stdout io.Writer, stderr io.Writer, deps
 		return writeAppError(stderr, err.Error(), exitCrash)
 	}
 	name := options.names[0]
+	// RemoveProvider only ever matches profiles persisted in config.json (see
+	// config.ProviderPersisted), but a provider can be visible in
+	// `zero providers list`/the TUI picker purely because Resolve()
+	// synthesized it in-memory from an ambient env var (e.g. OPENAI_API_KEY)
+	// without ever writing a row to disk. Without this check, deleting that
+	// provider by name always fails with a confusing "not found" even though
+	// it is genuinely visible/usable this session (issue #707).
+	persisted, err := config.ProviderPersisted(configPath, name)
+	if err != nil {
+		return writeAppError(stderr, err.Error(), exitCrash)
+	}
+	if !persisted {
+		if exit, handled := reportUnpersistedProviderRemove(stdout, stderr, deps, name, options.json, configPath); handled {
+			return exit
+		}
+	}
 	cfg, err := config.RemoveProvider(configPath, name)
 	if err != nil {
 		return writeAppError(stderr, err.Error(), exitCrash)
@@ -428,6 +460,16 @@ func runProvidersRename(args []string, stdout io.Writer, stderr io.Writer, deps
 	if err != nil {
 		return writeAppError(stderr, err.Error(), exitCrash)
 	}
+	oldName := options.names[0]
+	persisted, err := config.ProviderPersisted(configPath, oldName)
+	if err != nil {
+		return writeAppError(stderr, err.Error(), exitCrash)
+	}
+	if !persisted {
+		if exit, handled := reportUnpersistedProviderRename(stdout, stderr, deps, oldName, options.json, configPath); handled {
+			return exit
+		}
+	}
 	cfg, err := config.RenameProvider(configPath, options.names[0], options.names[1])
 	if err != nil {
 		return writeAppError(stderr, err.Error(), exitCrash)
@@ -447,3 +489,120 @@ func runProvidersRename(args []string, stdout io.Writer, stderr io.Writer, deps
 	}
 	return exitSuccess
 }
+
+// providerResolvedByName reports whether name matches a provider in a
+// resolved provider list — used to tell a genuinely unknown name (a typo)
+// apart from a real, env-derived provider that just has no config.json row.
+func providerResolvedByName(providers []config.ProviderProfile, name string) bool {
+	name = strings.TrimSpace(name)
+	for _, provider := range providers {
+		if strings.EqualFold(strings.TrimSpace(provider.Name), name) {
+			return true
+		}
+	}
+	return false
+}
+
+// reportUnpersistedProviderUse handles `zero providers use <name>` for a
+// provider that is not persisted in config.json. If it's not resolvable at
+// all (an unknown/misspelled name), it returns handled=false so the caller
+// falls through to SetActiveProvider's real "not found" error. If it IS
+// resolvable — an env-derived profile (e.g. ambient OPENAI_API_KEY) —
+// SetActiveProvider would only ever fail "not found" against it, so this
+// reports the situation plainly instead of that confusing error (issue
+// #707).
+func reportUnpersistedProviderUse(stdout, stderr io.Writer, deps appDeps, options providerUseOptions, configPath string) (int, bool) {
+	resolved, exitCode := resolveCommandCenterConfig(stderr, deps)
+	if exitCode != exitSuccess {
+		// resolveCommandCenterConfig already wrote its own error to stderr;
+		// stop here instead of letting the caller try SetActiveProvider too.
+		return exitCode, true
+	}
+	if !providerResolvedByName(resolved.Providers, options.name) {
+		return exitCode, false
+	}
+	message := fmt.Sprintf(
+		"Provider %q is not saved in config.json (likely set via an environment variable), so there is no saved profile to switch to.\nIt is available whenever its environment variable is set, but is only active when selected (for example via ZERO_PROVIDER); unset its environment variable to stop Zero from detecting it automatically.",
+		options.name,
+	)
+	if options.json {
+		if err := writePrettyJSON(stdout, map[string]any{
+			"activeProvider": resolved.ActiveProvider,
+			"configPath":     configPath,
+			"persisted":      false,
+			"message":        message,
+		}); err != nil {
+			return exitCrash, true
+		}
+		return exitSuccess, true
+	}
+	if _, err := fmt.Fprintln(stdout, message); err != nil {
+		return exitCrash, true
+	}
+	return exitSuccess, true
+}
+
+// reportUnpersistedProviderRemove handles `zero providers remove <name>` for
+// a provider that is not persisted in config.json, mirroring the TUI
+// provider manager's delete handling (internal/tui/provider_manager.go). If
+// name isn't resolvable at all, it returns handled=false so the caller falls
+// through to RemoveProvider's real "not found" error.
+func reportUnpersistedProviderRemove(stdout, stderr io.Writer, deps appDeps, name string, jsonOutput bool, configPath string) (int, bool) {
+	resolved, exitCode := resolveCommandCenterConfig(stderr, deps)
+	if exitCode != exitSuccess {
+		return exitCode, true
+	}
+	if !providerResolvedByName(resolved.Providers, name) {
+		return exitCode, false
+	}
+	message := fmt.Sprintf(
+		"Provider %q is not saved in config.json (likely set via an environment variable) — nothing to remove there.\nUnset its environment variable to stop Zero from detecting it automatically.",
+		name,
+	)
+	if jsonOutput {
+		if err := writePrettyJSON(stdout, map[string]any{
+			"removed":        "",
+			"keyRemoved":     false,
+			"activeProvider": resolved.ActiveProvider,
+			"configPath":     configPath,
+			"persisted":      false,
+			"message":        message,
+		}); err != nil {
+			return exitCrash, true
+		}
+		return exitSuccess, true
+	}
+	if _, err := fmt.Fprintln(stdout, message); err != nil {
+		return exitCrash, true
+	}
+	return exitSuccess, true
+}
+
+func reportUnpersistedProviderRename(stdout, stderr io.Writer, deps appDeps, name string, jsonOutput bool, configPath string) (int, bool) {
+	resolved, exitCode := resolveCommandCenterConfig(stderr, deps)
+	if exitCode != exitSuccess {
+		return exitCode, true
+	}
+	if !providerResolvedByName(resolved.Providers, name) {
+		return exitCode, false
+	}
+	message := fmt.Sprintf(
+		"Provider %q is not saved in config.json (likely set via an environment variable), so there is no saved profile to rename.",
+		name,
+	)
+	if jsonOutput {
+		if err := writePrettyJSON(stdout, map[string]any{
+			"renamed":    nil,
+			"configPath": configPath,
+			"persisted":  false,
+			"message":    message,
+		}); err != nil {
+			return exitCrash, true
+		}
+		return exitSuccess, true
+	}
+	if _, err := fmt.Fprintln(stdout, message); err != nil {
+		return exitCrash, true
+	}
+	return exitSuccess, true
+}

internal/cli/provider_onboarding_test.go

@@ -75,6 +75,111 @@ func TestRunProvidersUseJSONIncludesActiveProviderAndConfigPath(t *testing.T) {
 	}
 }
 
+func TestRunProvidersUseSurfacesMalformedConfig(t *testing.T) {
+	var stdout, stderr bytes.Buffer
+	configPath := filepath.Join(t.TempDir(), "config.json")
+	if err := os.WriteFile(configPath, []byte("{"), 0o600); err != nil {
+		t.Fatalf("write malformed config: %v", err)
+	}
+
+	exitCode := runWithDeps([]string{"providers", "use", "openai"}, &stdout, &stderr, providerSetupDeps(configPath))
+
+	if exitCode != exitCrash {
+		t.Fatalf("exit code = %d, want %d", exitCode, exitCrash)
+	}
+	if !strings.Contains(stderr.String(), "invalid config JSON") {
+		t.Fatalf("stderr = %q, want malformed-config error", stderr.String())
+	}
+}
+
+func TestRunProvidersUseEnvDerivedJSONIncludesConfigPath(t *testing.T) {
+	t.Setenv("OPENAI_API_KEY", "sk-env")
+	var stdout, stderr bytes.Buffer
+	configPath := filepath.Join(t.TempDir(), "config.json")
+	writeProviderOnboardingConfig(t, configPath, config.FileConfig{})
+
+	exitCode := runWithDeps([]string{"providers", "use", "openai", "--json"}, &stdout, &stderr, providerSetupDeps(configPath))
+
+	if exitCode != exitSuccess {
+		t.Fatalf("exit code = %d, want %d: %s", exitCode, exitSuccess, stderr.String())
+	}
+	var payload struct {
+		ConfigPath string `json:"configPath"`
+		Persisted  bool   `json:"persisted"`
+	}
+	if err := json.Unmarshal(stdout.Bytes(), &payload); err != nil {
+		t.Fatalf("decode JSON: %v\n%s", err, stdout.String())
+	}
+	if payload.ConfigPath != configPath || payload.Persisted {
+		t.Fatalf("unexpected payload: %+v", payload)
+	}
+}
+
+func TestRunProvidersRemoveEnvDerivedJSONKeepsSchema(t *testing.T) {
+	t.Setenv("OPENAI_API_KEY", "sk-env")
+	var stdout, stderr bytes.Buffer
+	configPath := filepath.Join(t.TempDir(), "config.json")
+	writeProviderOnboardingConfig(t, configPath, config.FileConfig{})
+
+	exitCode := runWithDeps([]string{"providers", "remove", "openai", "--json"}, &stdout, &stderr, providerSetupDeps(configPath))
+
+	if exitCode != exitSuccess {
+		t.Fatalf("exit code = %d, want %d: %s", exitCode, exitSuccess, stderr.String())
+	}
+	var payload struct {
+		Removed    string `json:"removed"`
+		KeyRemoved bool   `json:"keyRemoved"`
+		Persisted  bool   `json:"persisted"`
+		ConfigPath string `json:"configPath"`
+	}
+	if err := json.Unmarshal(stdout.Bytes(), &payload); err != nil {
+		t.Fatalf("decode JSON: %v\n%s", err, stdout.String())
+	}
+	if payload.Removed != "" || payload.KeyRemoved || payload.Persisted || payload.ConfigPath != configPath {
+		t.Fatalf("unexpected payload: %+v", payload)
+	}
+}
+
+func TestRunProvidersRenameEnvDerivedExplainsNoSavedProfile(t *testing.T) {
+	t.Setenv("OPENAI_API_KEY", "sk-env")
+	var stdout, stderr bytes.Buffer
+	configPath := filepath.Join(t.TempDir(), "config.json")
+	writeProviderOnboardingConfig(t, configPath, config.FileConfig{})
+
+	exitCode := runWithDeps([]string{"providers", "rename", "openai", "renamed"}, &stdout, &stderr, providerSetupDeps(configPath))
+
+	if exitCode != exitSuccess {
+		t.Fatalf("exit code = %d, want %d: %s", exitCode, exitSuccess, stderr.String())
+	}
+	if !strings.Contains(stdout.String(), "no saved profile to rename") {
+		t.Fatalf("stdout = %q, want unpersisted explanation", stdout.String())
+	}
+}
+
+func TestRunProvidersRenameEnvDerivedJSONKeepsSchema(t *testing.T) {
+	t.Setenv("OPENAI_API_KEY", "sk-env")
+	var stdout, stderr bytes.Buffer
+	configPath := filepath.Join(t.TempDir(), "config.json")
+	writeProviderOnboardingConfig(t, configPath, config.FileConfig{})
+
+	exitCode := runWithDeps([]string{"providers", "rename", "openai", "renamed", "--json"}, &stdout, &stderr, providerSetupDeps(configPath))
+
+	if exitCode != exitSuccess {
+		t.Fatalf("exit code = %d, want %d: %s", exitCode, exitSuccess, stderr.String())
+	}
+	var payload struct {
+		Renamed    *struct{} `json:"renamed"`
+		ConfigPath string    `json:"configPath"`
+		Persisted  bool      `json:"persisted"`
+	}
+	if err := json.Unmarshal(stdout.Bytes(), &payload); err != nil {
+		t.Fatalf("decode JSON: %v\n%s", err, stdout.String())
+	}
+	if payload.Renamed != nil || payload.ConfigPath != configPath || payload.Persisted {
+		t.Fatalf("unexpected payload: %+v", payload)
+	}
+}
+
 func TestRunProvidersUseRejectsUsageErrors(t *testing.T) {
 	cases := []struct {
 		name string

internal/cli/provider_setup.go

@@ -3,8 +3,10 @@ package cli
 import (
 	"fmt"
 	"io"
+	"net/http"
 	"strings"
 
+	"github.com/Gitlawb/zero/internal/aimlapi"
 	"github.com/Gitlawb/zero/internal/config"
 	"github.com/Gitlawb/zero/internal/providercatalog"
 	"github.com/Gitlawb/zero/internal/providerhealth"
@@ -424,22 +426,39 @@ func providerProfileForAdd(options providerAddOptions) (config.ProviderProfile,
 	if apiKeyEnv == "" && len(descriptor.AuthEnvVars) > 0 {
 		apiKeyEnv = descriptor.AuthEnvVars[0]
 	}
+	baseURL := firstNonEmptyCLI(options.baseURL, descriptor.DefaultBaseURL)
+	var catalogHeaders map[string]string
+	if sameProviderSetupBaseURL(baseURL, descriptor.DefaultBaseURL) {
+		catalogHeaders = descriptor.CustomHeaders
+		if strings.EqualFold(strings.TrimSpace(descriptor.ID), "aimlapi") {
+			catalogHeaders = aimlapi.WithResolvedPartnerHeader(catalogHeaders)
+		}
+	}
 	profile := config.ProviderProfile{
 		Name:            name,
 		ProviderKind:    providerKindForDescriptor(descriptor),
 		CatalogID:       descriptor.ID,
-		BaseURL:         firstNonEmptyCLI(options.baseURL, descriptor.DefaultBaseURL),
+		BaseURL:         baseURL,
 		APIKeyEnv:       apiKeyEnv,
 		APIFormat:       firstAPIFormat(descriptor),
 		AuthHeader:      strings.TrimSpace(options.authHeader),
 		AuthScheme:      normalizeAuthScheme(options.authScheme),
 		AuthHeaderValue: strings.TrimSpace(options.authHeaderValue),
-		CustomHeaders:   copyProviderHeaders(options.customHeaders),
-		Model:           firstNonEmptyCLI(options.model, descriptor.DefaultModel),
+		// Catalog attribution belongs only to the catalog endpoint. Explicit
+		// user headers still apply to an override/staging/proxy endpoint.
+		CustomHeaders: mergeProviderHeaders(catalogHeaders, options.customHeaders),
+		Model:         firstNonEmptyCLI(options.model, descriptor.DefaultModel),
 	}
 	return profile, nil
 }
 
+func sameProviderSetupBaseURL(left string, right string) bool {
+	return strings.EqualFold(
+		strings.TrimRight(strings.TrimSpace(left), "/"),
+		strings.TrimRight(strings.TrimSpace(right), "/"),
+	)
+}
+
 func selectProviderForCheck(resolved config.ResolvedConfig, name string) (config.ProviderProfile, error) {
 	name = strings.TrimSpace(name)
 	if name == "" {
@@ -544,3 +563,43 @@ func copyProviderHeaders(headers map[string]string) map[string]string {
 	}
 	return copied
 }
+
+func mergeProviderHeaders(base map[string]string, overrides map[string]string) map[string]string {
+	merged := copyProviderHeaders(base)
+	if len(overrides) == 0 {
+		return merged
+	}
+	if merged == nil {
+		merged = map[string]string{}
+	}
+	for key, value := range overrides {
+		// HTTP header names are case-insensitive and request construction
+		// canonicalizes them (http.Header.Set), so an override that differs from a
+		// base key only in case must replace that key's value in place — otherwise
+		// both survive as distinct map entries and race non-deterministically at
+		// build time. Keep the existing spelling (the catalog's, which the resolver
+		// re-merges verbatim); only a genuinely new header is added as typed.
+		if existing, ok := headerKeyFold(merged, key); ok {
+			merged[existing] = value
+			continue
+		}
+		merged[key] = value
+	}
+	return merged
+}
+
+// headerKeyFold returns the key in headers whose canonical HTTP form matches key,
+// so a case-insensitive override lands on the existing entry instead of adding a
+// colliding duplicate.
+func headerKeyFold(headers map[string]string, key string) (string, bool) {
+	if _, ok := headers[key]; ok {
+		return key, true
+	}
+	canonical := http.CanonicalHeaderKey(key)
+	for existing := range headers {
+		if http.CanonicalHeaderKey(existing) == canonical {
+			return existing, true
+		}
+	}
+	return "", false
+}

internal/cli/sandbox_sensitive_env_test.go

@@ -0,0 +1,23 @@
+package cli
+
+import (
+	"reflect"
+	"testing"
+
+	"github.com/Gitlawb/zero/internal/config"
+)
+
+func TestProviderSensitiveEnvKeys(t *testing.T) {
+	resolved := config.ResolvedConfig{
+		Providers: []config.ProviderProfile{
+			{Name: "custom", APIKeyEnv: " COMPANY_LLM_SECRET "},
+			{Name: "catalog", APIKeyEnv: "OPENAI_API_KEY"},
+			{Name: "inline"},
+		},
+		Provider: config.ProviderProfile{Name: "active", APIKeyEnv: "ACTIVE_PROVIDER_SECRET"},
+	}
+	want := []string{"COMPANY_LLM_SECRET", "OPENAI_API_KEY", "ACTIVE_PROVIDER_SECRET"}
+	if got := providerSensitiveEnvKeys(resolved); !reflect.DeepEqual(got, want) {
+		t.Fatalf("providerSensitiveEnvKeys() = %v, want %v", got, want)
+	}
+}

internal/cli/sandbox_test.go

@@ -1001,3 +1001,18 @@ func sandboxPolicyCapabilityStatus(capabilities []sandbox.BackendCapability, key
 	}
 	return ""
 }
+
+func TestApplyConfiguredSandboxPolicyEnabledFalseDisables(t *testing.T) {
+	disabled := false
+	if got := applyConfiguredSandboxPolicy(sandbox.DefaultPolicy(), config.SandboxConfig{Enabled: &disabled}); got.Mode != sandbox.ModeDisabled {
+		t.Fatalf("enabled:false must yield ModeDisabled, got %q", got.Mode)
+	}
+	// Omitted (nil) and explicit true keep the default enforcing mode.
+	if got := applyConfiguredSandboxPolicy(sandbox.DefaultPolicy(), config.SandboxConfig{}); got.Mode == sandbox.ModeDisabled {
+		t.Fatal("omitted enabled must not disable the sandbox")
+	}
+	enabled := true
+	if got := applyConfiguredSandboxPolicy(sandbox.DefaultPolicy(), config.SandboxConfig{Enabled: &enabled}); got.Mode == sandbox.ModeDisabled {
+		t.Fatal("enabled:true must not disable the sandbox")
+	}
+}

internal/cli/serve.go

@@ -4,6 +4,8 @@ import (
 	"context"
 	"fmt"
 	"io"
+	"os"
+	"path/filepath"
 	"strings"
 
 	"github.com/Gitlawb/zero/internal/mcp"
@@ -14,9 +16,21 @@ import (
 type serveOptions struct {
 	mcp              bool
 	cwd              string
+	addDirs          []string
 	allowUnsafeTools bool
 }
 
+// serveRootsScope is a PathScope used only for MCP serve: the workspace root
+// plus optional --add-dir roots, without the sandbox temp write roots that
+// would otherwise pollute resources/list.
+type serveRootsScope []string
+
+func (s serveRootsScope) Roots() []string {
+	roots := make([]string, len(s))
+	copy(roots, s)
+	return roots
+}
+
 func runServe(args []string, stdout io.Writer, stderr io.Writer, deps appDeps) int {
 	options, help, err := parseServeArgs(args)
 	if err != nil {
@@ -36,7 +50,11 @@ func runServe(args []string, stdout io.Writer, stderr io.Writer, deps appDeps) i
 	if err != nil {
 		return writeExecUsageError(stderr, err.Error())
 	}
-	registry := newServeRegistry(workspaceRoot, options.allowUnsafeTools)
+	scope, err := buildServeScope(workspaceRoot, options.addDirs)
+	if err != nil {
+		return writeExecUsageError(stderr, err.Error())
+	}
+	registry := newServeRegistry(workspaceRoot, scope, options.allowUnsafeTools)
 	if options.allowUnsafeTools {
 		if _, err := fmt.Fprintln(stderr, "[zero] Unsafe MCP server tools enabled because --allow-unsafe-tools was passed."); err != nil {
 			return exitCrash
@@ -47,6 +65,8 @@ func runServe(args []string, stdout io.Writer, stderr io.Writer, deps appDeps) i
 		Name:              "zero",
 		Version:           version,
 		PermissionGranted: options.allowUnsafeTools,
+		WorkspaceRoot:     workspaceRoot,
+		Scope:             scope,
 	})
 	if err != nil {
 		return writeAppError(stderr, redaction.ErrorMessage(err, redaction.Options{}), exitCrash)
@@ -54,11 +74,11 @@ func runServe(args []string, stdout io.Writer, stderr io.Writer, deps appDeps) i
 	return exitSuccess
 }
 
-func newServeRegistry(workspaceRoot string, allowUnsafeTools bool) *tools.Registry {
+func newServeRegistry(workspaceRoot string, scope tools.PathScope, allowUnsafeTools bool) *tools.Registry {
 	registry := tools.NewRegistry()
-	toolset := tools.CoreReadOnlyTools(workspaceRoot)
+	toolset := tools.CoreReadOnlyToolsScoped(workspaceRoot, scope)
 	if allowUnsafeTools {
-		toolset = tools.CoreTools(workspaceRoot)
+		toolset = tools.CoreToolsScoped(workspaceRoot, scope)
 	}
 	for _, tool := range toolset {
 		registry.Register(tool)
@@ -66,6 +86,58 @@ func newServeRegistry(workspaceRoot string, allowUnsafeTools bool) *tools.Regist
 	return registry
 }
 
+// buildServeScope returns nil when there are no extra roots (workspace-only),
+// otherwise a PathScope listing the workspace first followed by each --add-dir.
+func buildServeScope(workspaceRoot string, addDirs []string) (tools.PathScope, error) {
+	if len(addDirs) == 0 {
+		return nil, nil
+	}
+	roots := make([]string, 0, 1+len(addDirs))
+	workspaceRoot = filepath.Clean(workspaceRoot)
+	if abs, err := filepath.Abs(workspaceRoot); err == nil {
+		workspaceRoot = abs
+	}
+
+	// Keep lexical absolute paths in roots so path checks stay aligned with the
+	// un-evaluated WorkspaceRoot used when Scope is nil. Symlink-resolved forms
+	// are only keys for duplicate detection.
+	workspaceResolved := workspaceRoot
+	if resolved, err := filepath.EvalSymlinks(workspaceRoot); err == nil {
+		workspaceResolved = resolved
+	}
+	roots = append(roots, workspaceRoot)
+
+	seen := map[string]struct{}{workspaceResolved: {}}
+	for _, dir := range addDirs {
+		trimmed := strings.TrimSpace(dir)
+		if trimmed == "" {
+			return nil, execUsageError{"--add-dir requires a path"}
+		}
+		absolute, err := filepath.Abs(trimmed)
+		if err != nil {
+			return nil, execUsageError{fmt.Sprintf("--add-dir %q: %v", trimmed, err)}
+		}
+		info, err := os.Stat(absolute)
+		if err != nil {
+			return nil, execUsageError{fmt.Sprintf("--add-dir %q: %v", trimmed, err)}
+		}
+		if !info.IsDir() {
+			return nil, execUsageError{fmt.Sprintf("--add-dir %q is not a directory", trimmed)}
+		}
+
+		resolved := absolute
+		if r, err := filepath.EvalSymlinks(absolute); err == nil {
+			resolved = r
+		}
+		if _, ok := seen[resolved]; ok {
+			continue
+		}
+		seen[resolved] = struct{}{}
+		roots = append(roots, absolute)
+	}
+	return serveRootsScope(roots), nil
+}
+
 func parseServeArgs(args []string) (serveOptions, bool, error) {
 	options := serveOptions{}
 	for index := 0; index < len(args); index++ {
@@ -85,6 +157,18 @@ func parseServeArgs(args []string) (serveOptions, bool, error) {
 			options.cwd = args[index]
 		case strings.HasPrefix(arg, "--cwd="):
 			options.cwd = strings.TrimPrefix(arg, "--cwd=")
+		case arg == "--add-dir":
+			index++
+			if index >= len(args) {
+				return options, false, execUsageError{"--add-dir requires a path"}
+			}
+			options.addDirs = append(options.addDirs, args[index])
+		case strings.HasPrefix(arg, "--add-dir="):
+			value := strings.TrimPrefix(arg, "--add-dir=")
+			if strings.TrimSpace(value) == "" {
+				return options, false, execUsageError{"--add-dir requires a path"}
+			}
+			options.addDirs = append(options.addDirs, value)
 		default:
 			return options, false, execUsageError{fmt.Sprintf("unknown serve flag %q", arg)}
 		}
@@ -100,7 +184,8 @@ Starts Zero as an MCP stdio server.
 
 Flags:
       --mcp                   Run the MCP stdio server
-  -C, --cwd <path>            Set the workspace directory
+  -C, --cwd <path>            Set the workspace directory (resources + tools)
+      --add-dir <path>        Extra resource/tool root (repeatable)
       --allow-unsafe-tools    Expose write and shell tools to the MCP host
   -h, --help                  Show this help
 `)

internal/cli/serve_test.go

@@ -4,6 +4,8 @@ import (
 	"bytes"
 	"encoding/json"
 	"fmt"
+	"os"
+	"path/filepath"
 	"strings"
 	"testing"
 )
@@ -80,6 +82,120 @@ func TestRunServeRequiresMCPMode(t *testing.T) {
 	}
 }
 
+func TestRunServeMCPWiresWorkspaceRootAndAddDirIntoResources(t *testing.T) {
+	workspace := t.TempDir()
+	extra := t.TempDir()
+	if err := os.WriteFile(filepath.Join(workspace, "workspace.txt"), []byte("ws\n"), 0o600); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(filepath.Join(extra, "extra.txt"), []byte("ex\n"), 0o600); err != nil {
+		t.Fatal(err)
+	}
+
+	var stdout bytes.Buffer
+	var stderr bytes.Buffer
+	exitCode := runWithDeps(
+		[]string{"serve", "--mcp", "-C", workspace, "--add-dir", extra},
+		&stdout,
+		&stderr,
+		appDeps{stdin: bytes.NewReader(serveMCPResourcesInput(t))},
+	)
+	if exitCode != exitSuccess {
+		t.Fatalf("exit=%d stderr=%q", exitCode, stderr.String())
+	}
+	output := stdout.String()
+	if !strings.Contains(output, "workspace.txt") {
+		t.Fatalf("expected workspace resource, got %q", output)
+	}
+	if !strings.Contains(output, "extra.txt") {
+		t.Fatalf("expected --add-dir resource, got %q", output)
+	}
+}
+
+func TestRunServeMCPRejectsMissingAddDir(t *testing.T) {
+	workspace := t.TempDir()
+	missing := filepath.Join(workspace, "does-not-exist")
+	var stdout bytes.Buffer
+	var stderr bytes.Buffer
+	exitCode := runWithDeps(
+		[]string{"serve", "--mcp", "-C", workspace, "--add-dir", missing},
+		&stdout,
+		&stderr,
+		appDeps{stdin: bytes.NewReader(nil)},
+	)
+	if exitCode != exitUsage {
+		t.Fatalf("exit=%d want %d stderr=%q", exitCode, exitUsage, stderr.String())
+	}
+	if !strings.Contains(stderr.String(), "--add-dir") {
+		t.Fatalf("expected --add-dir error, got %q", stderr.String())
+	}
+}
+
+func TestParseServeArgsCollectsAddDirs(t *testing.T) {
+	options, help, err := parseServeArgs([]string{"--mcp", "--add-dir", "/one", "--add-dir=/two", "-C", "/ws"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if help {
+		t.Fatal("unexpected help")
+	}
+	if !options.mcp || options.cwd != "/ws" {
+		t.Fatalf("options=%#v", options)
+	}
+	if len(options.addDirs) != 2 || options.addDirs[0] != "/one" || options.addDirs[1] != "/two" {
+		t.Fatalf("addDirs=%v", options.addDirs)
+	}
+}
+
+func TestBuildServeScopeNilWithoutExtras(t *testing.T) {
+	scope, err := buildServeScope(t.TempDir(), nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if scope != nil {
+		t.Fatalf("expected nil scope, got %#v", scope)
+	}
+}
+
+func TestBuildServeScopeKeepsLexicalPaths(t *testing.T) {
+	base := t.TempDir()
+	realWorkspace := filepath.Join(base, "real-workspace")
+	realExtra := filepath.Join(base, "real-extra")
+	for _, dir := range []string{realWorkspace, realExtra} {
+		if err := os.MkdirAll(dir, 0o700); err != nil {
+			t.Fatal(err)
+		}
+	}
+	linkWorkspace := filepath.Join(base, "link-workspace")
+	linkExtra := filepath.Join(base, "link-extra")
+	if err := os.Symlink(realWorkspace, linkWorkspace); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.Symlink(realExtra, linkExtra); err != nil {
+		t.Fatal(err)
+	}
+
+	scope, err := buildServeScope(linkWorkspace, []string{linkExtra})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if scope == nil {
+		t.Fatal("expected non-nil scope")
+	}
+	roots := scope.Roots()
+	wantWorkspace, err := filepath.Abs(linkWorkspace)
+	if err != nil {
+		t.Fatal(err)
+	}
+	wantExtra, err := filepath.Abs(linkExtra)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(roots) != 2 || roots[0] != wantWorkspace || roots[1] != wantExtra {
+		t.Fatalf("roots=%v want [%q %q]", roots, wantWorkspace, wantExtra)
+	}
+}
+
 func serveMCPInput(t *testing.T) []byte {
 	t.Helper()
 
@@ -104,6 +220,30 @@ func serveMCPInput(t *testing.T) []byte {
 	return input.Bytes()
 }
 
+func serveMCPResourcesInput(t *testing.T) []byte {
+	t.Helper()
+
+	var input bytes.Buffer
+	writeServeMCPMessage(t, &input, map[string]any{
+		"jsonrpc": "2.0",
+		"id":      1,
+		"method":  "initialize",
+		"params":  map[string]any{},
+	})
+	writeServeMCPMessage(t, &input, map[string]any{
+		"jsonrpc": "2.0",
+		"method":  "notifications/initialized",
+		"params":  map[string]any{},
+	})
+	writeServeMCPMessage(t, &input, map[string]any{
+		"jsonrpc": "2.0",
+		"id":      2,
+		"method":  "resources/list",
+		"params":  map[string]any{},
+	})
+	return input.Bytes()
+}
+
 func writeServeMCPMessage(t *testing.T, buffer *bytes.Buffer, message map[string]any) {
 	t.Helper()
 	body, err := json.Marshal(message)

internal/cli/sessions.go

@@ -216,10 +216,10 @@ func parseNonEmptySessionsFlag(flag string, value string) (string, error) {
 func parseSessionKindFlag(value string) (sessions.SessionKind, error) {
 	kind := sessions.SessionKind(strings.ToLower(strings.TrimSpace(value)))
 	switch kind {
-	case sessions.SessionKindFork, sessions.SessionKindChild, sessions.SessionKindSpecDraft, sessions.SessionKindSpecImpl:
+	case sessions.SessionKindFork, sessions.SessionKindChild, sessions.SessionKindSide, sessions.SessionKindSpecDraft, sessions.SessionKindSpecImpl:
 		return kind, nil
 	default:
-		return "", execUsageError{fmt.Sprintf("invalid --kind %q. Expected fork, child, spec-draft, or spec-impl.", value)}
+		return "", execUsageError{fmt.Sprintf("invalid --kind %q. Expected fork, child, side, spec-draft, or spec-impl.", value)}
 	}
 }
 
@@ -535,7 +535,7 @@ Commands:
 
 Flags:
       --json            Print JSON output
-      --kind <kind>     Filter list by fork, child, spec-draft, or spec-impl
+      --kind <kind>     Filter list by fork, child, side, spec-draft, or spec-impl
       --sequence <n>    Rewind target sequence (rewind-plan, rewind)
       --event <id>      Rewind target event id (rewind-plan, rewind)
       --exclude-target  Drop the target event (rewind-plan, rewind)

internal/cli/sessions_test.go

@@ -233,6 +233,9 @@ func TestRunSessionsListFiltersByKind(t *testing.T) {
 	}); err != nil {
 		t.Fatal(err)
 	}
+	if _, err := store.Create(sessions.CreateInput{SessionID: "side", SessionKind: sessions.SessionKindSide, Title: "BTW side"}); err != nil {
+		t.Fatal(err)
+	}
 
 	var stdout bytes.Buffer
 	var stderr bytes.Buffer
@@ -249,6 +252,17 @@ func TestRunSessionsListFiltersByKind(t *testing.T) {
 		t.Fatalf("filtered sessions output = %q", output)
 	}
 
+	stdout.Reset()
+	stderr.Reset()
+	exitCode = runWithDeps([]string{"sessions", "list", "--kind", "side"}, &stdout, &stderr, appDeps{
+		newSessionStore: func() *sessions.Store {
+			return store
+		},
+	})
+	if exitCode != exitSuccess || !strings.Contains(stdout.String(), "side") || strings.Contains(stdout.String(), "regular") {
+		t.Fatalf("sessions list --kind side exit=%d stdout=%q stderr=%q", exitCode, stdout.String(), stderr.String())
+	}
+
 	stdout.Reset()
 	stderr.Reset()
 	exitCode = runWithDeps([]string{"sessions", "tree", "draft", "--kind", "spec-draft"}, &stdout, &stderr, appDeps{

internal/cli/setup_test.go

@@ -200,6 +200,54 @@ func TestSaveSetupProviderStoresPastedAPIKey(t *testing.T) {
 	}
 }
 
+func TestSaveSetupProviderAimlapiEnvReferenceAndOverrideHeaders(t *testing.T) {
+	configPath := filepath.Join(t.TempDir(), "zero", "config.json")
+	result, err := saveSetupProvider(appDeps{
+		userConfigPath: func() (string, error) { return configPath, nil },
+	}, tui.SetupSelection{
+		CatalogID: "aimlapi",
+		BaseURL:   "https://staging.example/v1",
+		Model:     "anthropic/claude-sonnet-5",
+	}, setupSaveOptions{})
+	if err != nil {
+		t.Fatalf("saveSetupProvider() error = %v", err)
+	}
+	if result.Provider.APIKey != "" || result.Provider.APIKeyEnv != "AIMLAPI_API_KEY" {
+		t.Fatalf("runtime profile did not retain AIMLAPI_API_KEY reference: %+v", result.Provider)
+	}
+	if len(result.Provider.CustomHeaders) != 0 {
+		t.Fatalf("catalog headers leaked to first-run override: %#v", result.Provider.CustomHeaders)
+	}
+	persisted := readFileConfig(t, configPath).Providers[0]
+	if persisted.APIKey != "" || persisted.APIKeyEnv != "AIMLAPI_API_KEY" || persisted.APIKeyStored {
+		t.Fatalf("persisted credential source changed: %+v", persisted)
+	}
+	if len(persisted.CustomHeaders) != 0 {
+		t.Fatalf("persisted override contains catalog headers: %#v", persisted.CustomHeaders)
+	}
+}
+
+func TestSaveSetupProviderAimlapiUsesResolvedPartnerOverride(t *testing.T) {
+	t.Setenv("AIMLAPI_PARTNER_ID", "part_override")
+	configPath := filepath.Join(t.TempDir(), "zero", "config.json")
+	result, err := saveSetupProvider(appDeps{
+		userConfigPath: func() (string, error) { return configPath, nil },
+	}, tui.SetupSelection{
+		CatalogID: "aimlapi",
+		BaseURL:   "https://api.aimlapi.com/v1",
+		Model:     "anthropic/claude-sonnet-5",
+	}, setupSaveOptions{})
+	if err != nil {
+		t.Fatalf("saveSetupProvider() error = %v", err)
+	}
+	if got := result.Provider.CustomHeaders["X-AIMLAPI-Partner-ID"]; got != "part_override" {
+		t.Fatalf("runtime partner header = %q, want part_override", got)
+	}
+	if got := readFileConfig(t, configPath).Providers[0].CustomHeaders["X-AIMLAPI-Partner-ID"]; got != "part_override" {
+		t.Fatalf("persisted partner header = %q, want part_override", got)
+	}
+}
+
 func TestSaveSetupProviderStoresCustomEndpointSelection(t *testing.T) {
 	configPath := filepath.Join(t.TempDir(), "zero", "config.json")
 

internal/cli/skills.go

@@ -59,25 +59,21 @@ func runSkills(args []string, stdout io.Writer, stderr io.Writer, deps appDeps)
 }
 
 func runSkillsList(dir string, options skillListOptions, stdout io.Writer, stderr io.Writer) int {
-	discovered, err := skills.List(dir)
+	// Management CLI lists global roots only (primary + ~/.agents/skills); plugin
+	// skills stay out of `zero skills list` and surface via the agent skill tool.
+	roots := skills.GlobalRoots(dir)
+	discovered, dups, err := skills.ListFromRoots(roots)
 	if err != nil {
 		return writeAppError(stderr, redaction.ErrorMessage(err, redaction.Options{}), exitCrash)
 	}
-	// Surface name collisions that List silently resolved (first directory wins),
-	// so a shadowed same-named skill is reported instead of just disappearing.
-	// Warnings go to stderr, keeping stdout (including --json) clean.
-	if dups, derr := skills.Duplicates(dir); derr == nil {
-		for _, dup := range dups {
-			fmt.Fprintf(stderr, "warning: duplicate skill %q: using %s, ignoring %s\n",
-				redaction.RedactString(dup.Name, redaction.Options{}),
-				redaction.RedactString(dup.Winner, redaction.Options{}),
-				redaction.RedactString(dup.Loser, redaction.Options{}))
-		}
-	} else {
-		// Don't silently swallow a scan failure: "no warnings" would then be
-		// ambiguous (no duplicates vs. detection broke). Surface it on stderr.
-		fmt.Fprintf(stderr, "warning: could not check for duplicate skills: %s\n",
-			redaction.ErrorMessage(derr, redaction.Options{}))
+	// Surface name collisions that ListFromRoots silently resolved (earlier root
+	// wins), so a shadowed same-named skill is reported instead of just
+	// disappearing. Warnings go to stderr, keeping stdout (including --json) clean.
+	for _, dup := range dups {
+		fmt.Fprintf(stderr, "warning: duplicate skill %q: using %s, ignoring %s\n",
+			redaction.RedactString(dup.Name, redaction.Options{}),
+			redaction.RedactString(dup.Winner, redaction.Options{}),
+			redaction.RedactString(dup.Loser, redaction.Options{}))
 	}
 	if options.json {
 		payload := struct {
@@ -88,16 +84,16 @@ func runSkillsList(dir string, options skillListOptions, stdout io.Writer, stder
 		}
 		return exitSuccess
 	}
-	output := redaction.RedactString(formatSkillList(discovered, dir), redaction.Options{})
+	output := redaction.RedactString(formatSkillList(discovered), redaction.Options{})
 	if _, err := fmt.Fprintln(stdout, output); err != nil {
 		return exitCrash
 	}
 	return exitSuccess
 }
 
-func formatSkillList(discovered []skills.Skill, dir string) string {
+func formatSkillList(discovered []skills.Skill) string {
 	if len(discovered) == 0 {
-		return fmt.Sprintf("No Zero skills found in %s.", dir)
+		return "No skills found."
 	}
 	lines := []string{"Zero Skills:"}
 	for _, skill := range discovered {
@@ -131,10 +127,13 @@ func writeSkillsHelp(w io.Writer) error {
   zero skills <command>
 
 Commands:
-  list                 List discovered Zero skills
-  add <git-url|path>   Install a skill (checksum-pinned in skills.lock)
+  list                 List discovered skills (Zero dir + ~/.agents/skills)
+  add <git-url|path>   Install a skill into the Zero skills dir (checksum-pinned in skills.lock)
   info <name>          Show a skill's frontmatter, source, and pinned hash
-  remove <name>        Remove an installed skill and its lockfile entry
+  remove <name>        Remove an installed skill and its lockfile entry from the Zero skills dir
+
+list and info also search ~/.agents/skills when present (read-only).
+add and remove always target the Zero-specific skills directory.
 `)
 	return err
 }

internal/cli/skills_test.go

@@ -23,7 +23,15 @@ func writeSkillFixture(t *testing.T, dir string, name string, content string) {
 	}
 }
 
+func isolateCLIAgentsHome(t *testing.T) {
+	t.Helper()
+	home := t.TempDir()
+	t.Setenv("HOME", home)
+	t.Setenv("USERPROFILE", home)
+}
+
 func TestRunSkillsListText(t *testing.T) {
+	isolateCLIAgentsHome(t)
 	dir := t.TempDir()
 	writeSkillFixture(t, dir, "confirmation-policy", "---\nname: confirmation-policy\ndescription: Ask before risky actions.\n---\nbody")
 
@@ -43,6 +51,7 @@ func TestRunSkillsListText(t *testing.T) {
 }
 
 func TestRunSkillsListWarnsOnDuplicateNames(t *testing.T) {
+	isolateCLIAgentsHome(t)
 	dir := t.TempDir()
 	// Two directories declare the same frontmatter name; List keeps one and the
 	// other is shadowed. The command must warn instead of silently dropping it.
@@ -62,6 +71,7 @@ func TestRunSkillsListWarnsOnDuplicateNames(t *testing.T) {
 }
 
 func TestRunSkillsDefaultsToList(t *testing.T) {
+	isolateCLIAgentsHome(t)
 	dir := t.TempDir()
 	writeSkillFixture(t, dir, "demo", "body")
 
@@ -78,6 +88,7 @@ func TestRunSkillsDefaultsToList(t *testing.T) {
 }
 
 func TestRunSkillsListJSON(t *testing.T) {
+	isolateCLIAgentsHome(t)
 	dir := t.TempDir()
 	writeSkillFixture(t, dir, "demo", "---\nname: demo\ndescription: a demo\n---\nbody")
 
@@ -111,6 +122,7 @@ func TestRunSkillsListJSON(t *testing.T) {
 }
 
 func TestRunSkillsEmptyDir(t *testing.T) {
+	isolateCLIAgentsHome(t)
 	var stdout, stderr bytes.Buffer
 	exit := runWithDeps([]string{"skills", "list"}, &stdout, &stderr, appDeps{
 		skillsDir: func() string { return filepath.Join(t.TempDir(), "missing") },
@@ -118,11 +130,89 @@ func TestRunSkillsEmptyDir(t *testing.T) {
 	if exit != 0 {
 		t.Fatalf("exit = %d, stderr = %s", exit, stderr.String())
 	}
-	if !strings.Contains(strings.ToLower(stdout.String()), "no") {
+	if !strings.Contains(strings.ToLower(stdout.String()), "no skills found") {
 		t.Fatalf("expected a no-skills message, got:\n%s", stdout.String())
 	}
 }
 
+func TestRunSkillsListIncludesAgentsOnlySkill(t *testing.T) {
+	home := t.TempDir()
+	t.Setenv("HOME", home)
+	t.Setenv("USERPROFILE", home)
+	agents := filepath.Join(home, ".agents", "skills")
+	writeSkillFixture(t, agents, "agents-only", "---\nname: agents-only\ndescription: Shared multi-agent skill.\n---\nbody")
+
+	primary := t.TempDir()
+	var stdout, stderr bytes.Buffer
+	exit := runWithDeps([]string{"skills", "list"}, &stdout, &stderr, appDeps{
+		skillsDir: func() string { return primary },
+	})
+	if exit != 0 {
+		t.Fatalf("exit = %d, stderr = %s", exit, stderr.String())
+	}
+	out := stdout.String()
+	if !strings.Contains(out, "agents-only") {
+		t.Fatalf("list should include agents-only skill:\n%s", out)
+	}
+	if !strings.Contains(out, agents) {
+		t.Fatalf("list should show agents path:\n%s", out)
+	}
+}
+
+func TestRunSkillsListPrimaryShadowsAgents(t *testing.T) {
+	home := t.TempDir()
+	t.Setenv("HOME", home)
+	t.Setenv("USERPROFILE", home)
+	agents := filepath.Join(home, ".agents", "skills")
+	primary := t.TempDir()
+	writeSkillFixture(t, primary, "shared", "---\nname: shared\ndescription: From primary.\n---\nbody")
+	writeSkillFixture(t, agents, "shared", "---\nname: shared\ndescription: From agents.\n---\nbody")
+
+	var stdout, stderr bytes.Buffer
+	exit := runWithDeps([]string{"skills", "list"}, &stdout, &stderr, appDeps{
+		skillsDir: func() string { return primary },
+	})
+	if exit != 0 {
+		t.Fatalf("exit = %d, stderr = %s", exit, stderr.String())
+	}
+	if !strings.Contains(stdout.String(), "From primary") {
+		t.Fatalf("primary should win list description:\n%s", stdout.String())
+	}
+	if !strings.Contains(stdout.String(), primary) {
+		t.Fatalf("primary path should be shown:\n%s", stdout.String())
+	}
+	if !strings.Contains(stderr.String(), `duplicate skill "shared"`) {
+		t.Fatalf("expected cross-root duplicate warning, got: %q", stderr.String())
+	}
+}
+
+func TestRunSkillInfoResolvesAgentsOnly(t *testing.T) {
+	home := t.TempDir()
+	t.Setenv("HOME", home)
+	t.Setenv("USERPROFILE", home)
+	agents := filepath.Join(home, ".agents", "skills")
+	writeSkillFixture(t, agents, "agents-info", "---\nname: agents-info\ndescription: Agents info.\n---\nbody")
+
+	primary := t.TempDir()
+	var stdout, stderr bytes.Buffer
+	exit := runWithDeps([]string{"skill", "info", "agents-info"}, &stdout, &stderr, appDeps{
+		skillsDir: func() string { return primary },
+	})
+	if exit != 0 {
+		t.Fatalf("exit = %d, stderr = %s", exit, stderr.String())
+	}
+	out := stdout.String()
+	if !strings.Contains(out, "agents-info") || !strings.Contains(out, "Agents info.") {
+		t.Fatalf("info missing agents skill:\n%s", out)
+	}
+	if strings.Contains(out, "source:") || strings.Contains(out, "hash:") {
+		t.Fatalf("agents-only info must not invent lock metadata:\n%s", out)
+	}
+	if !strings.Contains(out, agents) {
+		t.Fatalf("info should show agents path:\n%s", out)
+	}
+}
+
 func TestRunSkillsDoesNotLaunchTUI(t *testing.T) {
 	var stdout, stderr bytes.Buffer
 	launchCalled := false

internal/config/mcp_merge.go

@@ -6,7 +6,7 @@ import (
 	"strings"
 )
 
-func mergeMCPConfig(dst *MCPConfig, src MCPConfig) {
+func mergeMCPConfig(dst *MCPConfig, src MCPConfig, canReenable bool) {
 	if len(src.Servers) == 0 {
 		return
 	}
@@ -14,10 +14,14 @@ func mergeMCPConfig(dst *MCPConfig, src MCPConfig) {
 		dst.Servers = map[string]MCPServerConfig{}
 	}
 	for name, server := range src.Servers {
-		dst.Servers[name] = mergeMCPServer(dst.Servers[name], server)
+		dst.Servers[name] = mergeMCPServer(dst.Servers[name], server, canReenable)
 	}
 }
 
+// mergeProjectMCPConfig merges a project-scoped (lower-trust) MCP config into
+// dst. It never re-enables a server the user explicitly disabled or disabled a
+// server the user explicitly enabled: it merges with canReenable=false so the
+// trust-boundary guard in mergeMCPServer keeps the user's decision authoritative.
 func mergeProjectMCPConfig(dst *MCPConfig, src MCPConfig) error {
 	if len(src.Servers) == 0 {
 		return nil
@@ -27,7 +31,7 @@ func mergeProjectMCPConfig(dst *MCPConfig, src MCPConfig) error {
 	}
 	for name, server := range src.Servers {
 		base := dst.Servers[name]
-		candidate := mergeMCPServer(base, server)
+		candidate := mergeMCPServer(base, server, false)
 		if projectMCPServerTargetChanges(base, server) && hasInheritedMCPCredentialMaterial(server, candidate) {
 			return fmt.Errorf("project MCP server %q cannot override target while inheriting user credentials; set headers/env/oauth explicitly or use a new server name", name)
 		}
@@ -37,7 +41,11 @@ func mergeProjectMCPConfig(dst *MCPConfig, src MCPConfig) error {
 	return nil
 }
 
-func mergeMCPServer(base MCPServerConfig, next MCPServerConfig) MCPServerConfig {
+// mergeMCPServer merges a later config layer's MCP server into the base. The
+// canReenable flag marks the CLI-override scope, the only layer that is allowed
+// to lift a sticky user-level disable/enable decision (see the disabled-handling
+// block).
+func mergeMCPServer(base MCPServerConfig, next MCPServerConfig, canReenable bool) MCPServerConfig {
 	if strings.TrimSpace(next.Type) != "" {
 		base.Type = next.Type
 	}
@@ -62,8 +70,26 @@ func mergeMCPServer(base MCPServerConfig, next MCPServerConfig) MCPServerConfig
 	if next.OAuth != nil {
 		base.OAuth = next.OAuth
 	}
+	// Capture the higher-trust scope's prior decision before folding in
+	// next.disabledSet. The trust boundary must be evaluated against the state
+	// the higher-trust layer actually left behind, not against next's own flag.
+	baseDisabledSet := base.disabledSet
+	baseDisabled := base.Disabled
+	if next.disabledSet {
+		base.disabledSet = true
+	}
 	if next.disabledSet || next.Disabled {
-		base.Disabled = next.Disabled
+		// Trust boundary: once a higher-trust scope has explicitly set the
+		// disabled flag, a lower-trust layer (project config) cannot override
+		// that decision in either direction — the user's choice (whether to
+		// enable or disable a server) wins over the repo. This blocks a repo
+		// from re-enabling a server the user disabled, and from disabling a
+		// server the user explicitly enabled. The only layer allowed to
+		// override an explicit higher-scope decision is the CLI override scope
+		// (canReenable=true).
+		if canReenable || !(baseDisabledSet && baseDisabled != next.Disabled) {
+			base.Disabled = next.Disabled
+		}
 	}
 	if next.configured {
 		base.configured = true
@@ -75,7 +101,7 @@ func mergeMCPServer(base MCPServerConfig, next MCPServerConfig) MCPServerConfig
 }
 
 func projectMCPServerTargetChanges(base MCPServerConfig, next MCPServerConfig) bool {
-	if strings.TrimSpace(next.Type) != "" && mcpServerTransportKind(base) != mcpServerTransportKind(mergeMCPServer(base, next)) {
+	if strings.TrimSpace(next.Type) != "" && mcpServerTransportKind(base) != mcpServerTransportKind(mergeMCPServer(base, next, true)) {
 		return true
 	}
 	if strings.TrimSpace(next.URL) != "" && strings.TrimSpace(next.URL) != strings.TrimSpace(base.URL) {

internal/config/resolver.go

@@ -9,6 +9,7 @@ import (
 	"strconv"
 	"strings"
 
+	"github.com/Gitlawb/zero/internal/aimlapi"
 	"github.com/Gitlawb/zero/internal/modelregistry"
 	"github.com/Gitlawb/zero/internal/notify"
 	"github.com/Gitlawb/zero/internal/providercatalog"
@@ -92,6 +93,16 @@ func Resolve(options ResolveOptions) (ResolvedConfig, error) {
 		if err != nil {
 			return ResolvedConfig{}, err
 		}
+		// Sandbox.Enabled is NOT accepted from a provider command, for the same
+		// reason project config cannot set it (see mergeProjectConfig): only
+		// global config and the CLI may turn the sandbox off. A provider command
+		// is an arbitrary executable named in config, and LoadProviderCommand
+		// parses its stdout into a full FileConfig — so without this, a command
+		// returning a valid provider plus {"sandbox":{"enabled":false}} would
+		// disable the very sandbox meant to constrain what it can do. Cleared
+		// here rather than in mergeConfig because that helper is shared with the
+		// trusted global-config merge, which must keep honouring the setting.
+		commandConfig.Sandbox.Enabled = nil
 		mergeConfig(&cfg, commandConfig)
 	}
 
@@ -170,7 +181,10 @@ func ResolveMCP(options ResolveOptions) (MCPConfig, error) {
 		if err != nil {
 			return MCPConfig{}, err
 		}
-		mergeMCPConfig(&cfg.MCP, fileConfig.MCP)
+		// User config is higher-trust than project config: it may re-enable a
+		// server the user disabled (a user-level disable is sticky, but the user
+		// scope itself may lift it).
+		mergeMCPConfig(&cfg.MCP, fileConfig.MCP, true)
 	}
 	// Drop the project layer when the workspace is untrusted, so a cloned repo's
 	// ./.zero/config.json cannot register (and spawn) MCP servers. Fail-closed:
@@ -184,7 +198,7 @@ func ResolveMCP(options ResolveOptions) (MCPConfig, error) {
 			return MCPConfig{}, err
 		}
 	}
-	mergeMCPConfig(&cfg.MCP, options.Overrides.MCP)
+	mergeMCPConfig(&cfg.MCP, options.Overrides.MCP, true)
 	return cfg.MCP, nil
 }
 
@@ -211,7 +225,10 @@ func mergeConfig(dst *FileConfig, src FileConfig) {
 	for _, provider := range src.Providers {
 		mergeProvider(dst, provider)
 	}
-	mergeMCPConfig(&dst.MCP, src.MCP)
+	mergeMCPConfig(&dst.MCP, src.MCP, true)
+	if src.Sandbox.Enabled != nil {
+		dst.Sandbox.Enabled = src.Sandbox.Enabled
+	}
 	if network := strings.TrimSpace(src.Sandbox.Network); network != "" {
 		dst.Sandbox.Network = network
 	}
@@ -269,6 +286,10 @@ func mergeProjectConfig(dst *FileConfig, src FileConfig) error {
 	if err := mergeProjectMCPConfig(&dst.MCP, src.MCP); err != nil {
 		return err
 	}
+	// Sandbox.Enabled is intentionally NOT merged from project config: a cloned
+	// repo's .zero/config.json must not be able to disable the sandbox that
+	// constrains it. Only global config and CLI can turn the sandbox off.
+	//
 	// Sandbox.AdditionalWriteRoots is intentionally NOT merged from project
 	// config: a cloned repo's .zero/config.json must not be able to grant
 	// itself write access outside the workspace. Global config and CLI flags
@@ -684,6 +705,9 @@ func applyOverrides(cfg *FileConfig, overrides Overrides) {
 	if overrides.MaxTurns > 0 {
 		cfg.MaxTurns = overrides.MaxTurns
 	}
+	if overrides.Sandbox.Enabled != nil {
+		cfg.Sandbox.Enabled = overrides.Sandbox.Enabled
+	}
 	if overrides.Sandbox.BlockUnixSockets {
 		cfg.Sandbox.BlockUnixSockets = true
 	}
@@ -709,7 +733,7 @@ func applyOverrides(cfg *FileConfig, overrides Overrides) {
 	if hasProviderFields(overrides.Provider) {
 		mergeProvider(cfg, overrides.Provider)
 	}
-	mergeMCPConfig(&cfg.MCP, overrides.MCP)
+	mergeMCPConfig(&cfg.MCP, overrides.MCP, true)
 }
 
 func mergeLocalControlConfig(dst *LocalControlConfig, src LocalControlConfig) {
@@ -1039,6 +1063,45 @@ func applyCatalogDescriptor(profile *ProviderProfile, descriptor providercatalog
 	if profile.APIKeyEnv == "" && len(descriptor.AuthEnvVars) > 0 && (!explicitBaseURL || sameBaseURL(profile.BaseURL, descriptor.DefaultBaseURL)) {
 		profile.APIKeyEnv = descriptor.AuthEnvVars[0]
 	}
+	canonicalCatalogEndpoint := !explicitBaseURL || sameBaseURL(profile.BaseURL, descriptor.DefaultBaseURL)
+	if len(descriptor.CustomHeaders) > 0 && canonicalCatalogEndpoint {
+		catalogHeaders := descriptor.CustomHeaders
+		if strings.EqualFold(strings.TrimSpace(descriptor.ID), "aimlapi") {
+			catalogHeaders = aimlapi.WithResolvedPartnerHeader(catalogHeaders)
+		}
+		merged := copyStringMap(catalogHeaders)
+		for key, value := range profile.CustomHeaders {
+			// Header names are case-insensitive. Preserve the catalog spelling while
+			// replacing its value so request construction cannot see two colliding
+			// map entries whose eventual winner depends on iteration order.
+			existingKey := ""
+			for candidate := range merged {
+				if strings.EqualFold(candidate, key) {
+					existingKey = candidate
+					break
+				}
+			}
+			if existingKey != "" {
+				merged[existingKey] = value
+				continue
+			}
+			merged[key] = value
+		}
+		profile.CustomHeaders = merged
+	} else if strings.EqualFold(strings.TrimSpace(descriptor.ID), "aimlapi") && !canonicalCatalogEndpoint {
+		// AIMLAPI attribution is owned by the catalog endpoint. A profile can retain
+		// those generated headers after its base URL is edited; strip their names
+		// before sending requests to an arbitrary staging/proxy host while preserving
+		// unrelated headers explicitly supplied by the user.
+		for profileKey := range profile.CustomHeaders {
+			for catalogKey := range descriptor.CustomHeaders {
+				if strings.EqualFold(profileKey, catalogKey) {
+					delete(profile.CustomHeaders, profileKey)
+					break
+				}
+			}
+		}
+	}
 }
 
 func sameBaseURL(left string, right string) bool {

internal/config/resolver_test.go

@@ -9,6 +9,7 @@ import (
 	"testing"
 
 	"github.com/Gitlawb/zero/internal/modelregistry"
+	"github.com/Gitlawb/zero/internal/providercatalog"
 )
 
 func TestResolveAppliesLayerPrecedence(t *testing.T) {
@@ -554,7 +555,7 @@ func TestResolveReplacesMCPServerOverlayCollections(t *testing.T) {
 	}
 }
 
-func TestResolveMCPServerLayersCanClearAndReenable(t *testing.T) {
+func TestResolveMCPServerLayersCannotReenableUserDisabled(t *testing.T) {
 	userPath := writeConfig(t, `{
 		"mcp": {
 			"servers": {
@@ -588,9 +589,11 @@ func TestResolveMCPServerLayersCanClearAndReenable(t *testing.T) {
 	}
 
 	docs := resolved.MCP.Servers["docs"]
-	if docs.Disabled {
-		t.Fatalf("docs.Disabled = true, want project layer to re-enable")
+	// A user-level disable is sticky: project config must not re-enable it.
+	if !docs.Disabled {
+		t.Fatal("docs.Disabled = false, want user-level disable to remain sticky")
 	}
+	// Non-disable fields from the project layer still merge normally.
 	if len(docs.Args) != 0 {
 		t.Fatalf("docs.Args = %#v, want project layer to clear inherited args", docs.Args)
 	}
@@ -599,6 +602,125 @@ func TestResolveMCPServerLayersCanClearAndReenable(t *testing.T) {
 	}
 }
 
+func TestMergeMCPStickyDisableReenable(t *testing.T) {
+	disabled := MCPServerConfig{Disabled: true, disabledSet: true}
+
+	// A lower-trust (project) layer must not lift a sticky user disable.
+	project := MCPServerConfig{Disabled: false, disabledSet: true}
+	if got := mergeMCPServer(disabled, project, false); !got.Disabled {
+		t.Fatal("project layer re-enabled a sticky user disable")
+	}
+
+	// The user scope (explicit mcp enable command / CLI override) may re-enable.
+	override := MCPServerConfig{Disabled: false, disabledSet: true}
+	if got := mergeMCPServer(disabled, override, true); got.Disabled {
+		t.Fatal("user-scope override must be able to re-enable")
+	}
+
+	// A user-scope disable stacked on a project attempt still sticks.
+	if got := mergeMCPServer(disabled, project, false); !got.Disabled {
+		t.Fatal("sticky disable must survive a project re-enable attempt")
+	}
+
+	// Baseline: a project layer may disable a default-enabled server when no
+	// higher-trust scope has explicitly set disabled (the trust boundary must
+	// not block legitimate project disables). Regression guard for the
+	// disabledSet-before-check ordering bug.
+	defaultEnabled := MCPServerConfig{Disabled: false, disabledSet: false}
+	projectDisable := MCPServerConfig{Disabled: true, disabledSet: true}
+	if got := mergeMCPServer(defaultEnabled, projectDisable, false); !got.Disabled {
+		t.Fatal("project layer should be able to disable a default-enabled server")
+	}
+
+	// And an empty project layer must not flip an unconfigured server to disabled.
+	if got := mergeMCPServer(MCPServerConfig{}, MCPServerConfig{}, false); got.Disabled {
+		t.Fatal("an empty project layer must not disable an unconfigured server")
+	}
+}
+
+// TestResolveMCPCannotReenableUserDisabled exercises the trust boundary at the
+// actual ResolveMCP entry point: a project config (project scope) must not lift
+// a disable the user set in their higher-trust user config.
+func TestResolveMCPCannotReenableUserDisabled(t *testing.T) {
+	userPath := writeConfig(t, `{
+		"mcp": {
+			"servers": {
+				"docs": {
+					"type": "stdio",
+					"command": "docs-mcp",
+					"disabled": true
+				}
+			}
+		}
+	}`)
+	// Project config tries to re-enable it.
+	projectPath := writeConfig(t, `{
+		"mcpServers": {
+			"docs": {
+				"disabled": false
+			}
+		}
+	}`)
+
+	resolved, err := ResolveMCP(ResolveOptions{
+		UserConfigPath:    userPath,
+		ProjectConfigPath: projectPath,
+	})
+	if err != nil {
+		t.Fatalf("ResolveMCP() error = %v", err)
+	}
+
+	docs, ok := resolved.Servers["docs"]
+	if !ok {
+		t.Fatal("docs server missing from resolved config")
+	}
+	if !docs.Disabled {
+		t.Fatalf("docs.Disabled = false, want user-level disable to remain sticky across project re-enable")
+	}
+}
+
+// TestResolveMCPUserLiftsProjectDisabled asserts the reverse direction is open:
+// a user config (higher-trust scope) re-enabling a server the project config
+// disabled must be permitted, since user > project in the trust hierarchy.
+func TestResolveMCPUserLiftsProjectDisabled(t *testing.T) {
+	// Project config disables the server.
+	projectPath := writeConfig(t, `{
+		"mcpServers": {
+			"docs": {
+				"type": "stdio",
+				"command": "docs-mcp",
+				"disabled": true
+			}
+		}
+	}`)
+	// User config re-enables it.
+	userPath := writeConfig(t, `{
+		"mcp": {
+			"servers": {
+				"docs": {
+					"disabled": false
+				}
+			}
+		}
+	}`)
+
+	resolved, err := ResolveMCP(ResolveOptions{
+		UserConfigPath:    userPath,
+		ProjectConfigPath: projectPath,
+	})
+	if err != nil {
+		t.Fatalf("ResolveMCP() error = %v", err)
+	}
+
+	docs, ok := resolved.Servers["docs"]
+	if !ok {
+		t.Fatal("docs server missing from resolved config")
+	}
+	if docs.Disabled {
+		t.Fatalf("docs.Disabled = true, want user scope to lift the project-level disable")
+	}
+}
+
 func TestResolveRejectsDuplicateMCPRootAliases(t *testing.T) {
 	path := writeConfig(t, `{
 		"mcpServers": {
@@ -1374,6 +1496,71 @@ func TestResolveProviderProfileExtendedJSONAliases(t *testing.T) {
 	}
 }
 
+func TestApplyCatalogDescriptorFoldsCustomHeadersCaseInsensitively(t *testing.T) {
+	t.Setenv("AIMLAPI_PARTNER_ID", "part_env")
+	descriptor, err := providercatalog.Require("aimlapi")
+	if err != nil {
+		t.Fatal(err)
+	}
+	profile := ProviderProfile{
+		BaseURL: descriptor.DefaultBaseURL,
+		CustomHeaders: map[string]string{
+			"x-aimlapi-partner-id": "part_override",
+		},
+	}
+
+	applyCatalogDescriptor(&profile, descriptor, true)
+
+	if got := profile.CustomHeaders["X-AIMLAPI-Partner-ID"]; got != "part_override" {
+		t.Fatalf("canonical header value = %q, want override", got)
+	}
+	if _, duplicate := profile.CustomHeaders["x-aimlapi-partner-id"]; duplicate {
+		t.Fatalf("case-colliding header survived merge: %#v", profile.CustomHeaders)
+	}
+}
+
+func TestApplyCatalogDescriptorUsesAimlapiPartnerEnvironmentOverride(t *testing.T) {
+	t.Setenv("AIMLAPI_PARTNER_ID", "part_env")
+	descriptor, err := providercatalog.Require("aimlapi")
+	if err != nil {
+		t.Fatal(err)
+	}
+	profile := ProviderProfile{BaseURL: descriptor.DefaultBaseURL}
+
+	applyCatalogDescriptor(&profile, descriptor, true)
+
+	if got := profile.CustomHeaders["X-AIMLAPI-Partner-ID"]; got != "part_env" {
+		t.Fatalf("partner header = %q, want part_env", got)
+	}
+}
+
+func TestApplyCatalogDescriptorStripsAimlapiAttributionFromRetargetedProfile(t *testing.T) {
+	descriptor, err := providercatalog.Require("aimlapi")
+	if err != nil {
+		t.Fatal(err)
+	}
+	profile := ProviderProfile{
+		BaseURL: "https://proxy.example.test/v1",
+		CustomHeaders: map[string]string{
+			"x-aimlapi-partner-id":          "persisted-partner",
+			"X-AIMLAPI-Integration-Repo":    "Gitlawb/zero",
+			"X-AIMLAPI-Integration-Version": "zero",
+			"X-Environment":                 "staging",
+		},
+	}
+
+	applyCatalogDescriptor(&profile, descriptor, true)
+
+	for key := range profile.CustomHeaders {
+		if strings.HasPrefix(strings.ToLower(key), "x-aimlapi-") {
+			t.Fatalf("catalog attribution survived retargeting: %#v", profile.CustomHeaders)
+		}
+	}
+	if profile.CustomHeaders["X-Environment"] != "staging" {
+		t.Fatalf("user header was removed: %#v", profile.CustomHeaders)
+	}
+}
+
 func TestResolveProviderProfileParseThinkTagsFalseAlias(t *testing.T) {
 	path := writeConfig(t, `{
 		"activeProvider": "custom",
@@ -1557,6 +1744,85 @@ func TestResolveSandboxNetworkProjectConfigCannotWeaken(t *testing.T) {
 	}
 }
 
+func TestResolveSandboxEnabledUserConfigDisables(t *testing.T) {
+	userPath := writeConfig(t, `{"sandbox": {"enabled": false}}`)
+	resolved, err := Resolve(ResolveOptions{UserConfigPath: userPath, Env: map[string]string{}})
+	if err != nil {
+		t.Fatalf("Resolve: %v", err)
+	}
+	if resolved.Sandbox.Enabled == nil || *resolved.Sandbox.Enabled {
+		t.Fatalf("user config enabled:false must resolve to a false pointer, got %v", resolved.Sandbox.Enabled)
+	}
+}
+
+func TestResolveSandboxDisableIgnoredFromProjectConfig(t *testing.T) {
+	// Security: a cloned repo's project config must NOT be able to disable the
+	// sandbox that constrains it. Only global config / CLI can turn it off.
+	userPath := writeConfig(t, `{}`)
+	projectPath := writeConfig(t, `{"sandbox": {"enabled": false}}`)
+	resolved, err := Resolve(ResolveOptions{UserConfigPath: userPath, ProjectConfigPath: projectPath, Env: map[string]string{}})
+	if err != nil {
+		t.Fatalf("Resolve: %v", err)
+	}
+	if resolved.Sandbox.Enabled != nil {
+		t.Fatalf("project config enabled:false must be ignored, got %v — a repo could disable the sandbox", *resolved.Sandbox.Enabled)
+	}
+}
+
+func TestResolveSandboxEnabledIgnoredFromProviderCommand(t *testing.T) {
+	// Security: a provider command is an arbitrary executable named in config, and
+	// its stdout is parsed into a full FileConfig — so it must NOT be able to reach
+	// Sandbox.Enabled, in either direction. Same rule as project config: only global
+	// config / CLI may turn the sandbox off.
+	for _, tc := range []struct {
+		name  string
+		value string
+	}{
+		{name: "cannot disable", value: "false"},
+		{name: "cannot enable", value: "true"},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			command := writeCommand(t, commandScript{
+				Stdout: `{"activeProvider":"cmd","providers":[{"name":"cmd","provider":"openai","apiKey":"sk-command","model":"gpt-command"}],"sandbox":{"enabled":` + tc.value + `}}`,
+			})
+			resolved, err := Resolve(ResolveOptions{ProviderCommand: command, Env: map[string]string{}})
+			if err != nil {
+				t.Fatalf("Resolve: %v", err)
+			}
+			// The provider itself must still be applied — only the sandbox toggle is dropped.
+			if resolved.ActiveProvider != "cmd" {
+				t.Fatalf("ActiveProvider = %q, want cmd (provider command must still apply)", resolved.ActiveProvider)
+			}
+			if resolved.Sandbox.Enabled != nil {
+				t.Fatalf("provider command set sandbox.enabled=%s, got %v — a provider command could toggle the sandbox", tc.value, *resolved.Sandbox.Enabled)
+			}
+		})
+	}
+}
+
+func TestResolveSandboxEnabledCLIOverride(t *testing.T) {
+	// A CLI/programmatic override (applied after every config source) must be able
+	// to disable the sandbox, even with no config file.
+	disabled := false
+	resolved, err := Resolve(ResolveOptions{Env: map[string]string{}, Overrides: Overrides{Sandbox: SandboxConfig{Enabled: &disabled}}})
+	if err != nil {
+		t.Fatalf("Resolve: %v", err)
+	}
+	if resolved.Sandbox.Enabled == nil || *resolved.Sandbox.Enabled {
+		t.Fatalf("CLI override enabled:false must disable the sandbox, got %v", resolved.Sandbox.Enabled)
+	}
+	// An explicit true override must win over a lower-precedence global-config false.
+	userPath := writeConfig(t, `{"sandbox": {"enabled": false}}`)
+	enabled := true
+	resolved2, err := Resolve(ResolveOptions{UserConfigPath: userPath, Env: map[string]string{}, Overrides: Overrides{Sandbox: SandboxConfig{Enabled: &enabled}}})
+	if err != nil {
+		t.Fatalf("Resolve: %v", err)
+	}
+	if resolved2.Sandbox.Enabled == nil || !*resolved2.Sandbox.Enabled {
+		t.Fatalf("CLI override enabled:true must win over config false, got %v", resolved2.Sandbox.Enabled)
+	}
+}
+
 func TestResolveNotifyValid(t *testing.T) {
 	path := writeConfig(t, `{"notify":{"mode":"both","focusMode":"always"}}`)
 	resolved, err := Resolve(ResolveOptions{UserConfigPath: path, Env: map[string]string{}})

internal/config/types.go

@@ -62,6 +62,12 @@ func HasProviderProfile(profile ProviderProfile) bool {
 }
 
 type SandboxConfig struct {
+	// Enabled turns the sandbox off when set to false (`"sandbox": {"enabled":
+	// false}`). A pointer distinguishes an explicit false (disable) from an
+	// omitted key (keep the default: enabled). Honored from the GLOBAL user
+	// config and CLI only — deliberately NOT project config, so a cloned repo
+	// cannot disable the sandbox that constrains it. nil / true keep enforcement.
+	Enabled *bool `json:"enabled,omitempty"`
 	// Network controls whether shell commands classified as network-touching
 	// (curl, git push, package installs, …) are allowed: "allow" or "deny".
 	// Empty keeps the built-in default (deny). Without this knob the engine's

internal/config/writer.go

@@ -177,6 +177,33 @@ func SetActiveProvider(path string, name string) (FileConfig, error) {
 	return FileConfig{}, fmt.Errorf("provider %q not found", name)
 }
 
+// ProviderPersisted reports whether a provider profile named name actually has
+// a row in the config file at path. A provider can appear in the resolved/
+// in-memory provider list without ever being written to config.json — e.g.
+// applyProviderEnv synthesizes an "openai" profile purely from an ambient
+// OPENAI_API_KEY environment variable on every Resolve() call, without ever
+// persisting it. RemoveProvider/SetActiveProvider/SetProviderModel only ever
+// look at what's on disk, so a caller offering to mutate a provider by name
+// should check this first: "not on disk" needs different handling (nothing to
+// persist/remove there) than a name that doesn't exist anywhere at all.
+func ProviderPersisted(path string, name string) (bool, error) {
+	path = strings.TrimSpace(path)
+	name = strings.TrimSpace(name)
+	if path == "" || name == "" {
+		return false, nil
+	}
+	cfg, err := loadConfigFile(path)
+	if err != nil {
+		return false, err
+	}
+	for _, provider := range cfg.Providers {
+		if strings.EqualFold(strings.TrimSpace(provider.Name), name) {
+			return true, nil
+		}
+	}
+	return false, nil
+}
+
 // RemoveProvider deletes the named provider profile from the config at path.
 // When the removed profile was active, activeProvider hands off to the first
 // remaining provider (or clears when none remain) so the config never points at

internal/execprofile/profile.go

@@ -0,0 +1,153 @@
+// Package execprofile defines named execution profiles: bundles of loop-posture
+// knobs (turn budget, reasoning effort, self-correction, escalation triggers)
+// that tune how hard the agent loop tries, independent of which model runs.
+// Profiles COMPOSE with --mode: a mode answers "what runs" (model, tools),
+// a profile answers "how hard the loop tries". Selection precedence is
+// explicit flag > --mode > profile, enforced by the callers applying profiles
+// last with the same fill-only-if-unset rule modes use.
+//
+// The catalog is deliberately tiny and value-stable: balanced is the empty
+// profile (selecting it leaves the run's options, budget, and loop behavior
+// identical to an unflagged run — asserted by test; only the opt-in trace and
+// bench artifacts record the selected profile name, by design, so captures are
+// self-describing), fast trades turn budget and effort for latency with a
+// one-shot escalation back to the displaced posture as the safety net, and
+// thorough raises the budget and arms full self-correction.
+package execprofile
+
+import (
+	"sort"
+	"strings"
+
+	"github.com/Gitlawb/zero/internal/agent"
+	"github.com/Gitlawb/zero/internal/sandbox"
+)
+
+// Profile is a named execution posture. Zero-valued fields inherit the run's
+// existing value (flag, mode, config, or built-in default) — a profile only
+// ever fills knobs the caller left unset, except MaxTurns which REPLACES the
+// resolved budget (that displacement is what escalation restores).
+type Profile struct {
+	// Name identifies the profile in traces, help text, and diagnostics.
+	Name string
+	// MaxTurns replaces the resolved per-run tool-turn budget when > 0 and the
+	// user did not pass an explicit --max-turns. The displaced resolved value
+	// becomes the escalation target (see Policy).
+	MaxTurns int
+	// ReasoningEffort fills the run's effort when the user left it unset. It
+	// still flows through the model-supported gating at the call site, so an
+	// unsupported level degrades exactly like an explicit flag would.
+	ReasoningEffort string
+	// SelfCorrect arms the post-edit verify-and-correct loop. Profiles can only
+	// turn it ON (the flag is presence-only, so false is indistinguishable from
+	// unset and must never override an explicit opt-in).
+	SelfCorrect bool
+
+	// Escalation triggers. All zero means the profile never escalates and
+	// Policy returns nil (the loop stays byte-identical to a nil-profile run).
+	// Targets are NOT part of the catalog: escalation restores the values the
+	// profile displaced at selection time, never invented ones, so targets are
+	// stamped by Policy from what the caller measured.
+	EscalateOnToolFailureStreak   int
+	EscalateOnCompletionUncertain int
+	EscalateOnSelfCorrectFailure  bool
+	EscalateOnRiskyMutation       sandbox.RiskLevel
+}
+
+// The catalog. Values marked provisional are floors/ceilings derived from the
+// Phase 0 baseline's read-class evidence (successful nav runs used single-digit
+// turns; the mutating classes produced no successful samples to tune from) and
+// are expected to be re-tuned from the post-oracle-fix re-capture. The
+// escalation safety net is what makes shipping provisional Fast values safe:
+// a run that hits trouble gets its displaced budget back mid-run.
+var (
+	// Balanced is the default posture: empty on purpose. Selecting it changes
+	// nothing — the no-regression invariant of the whole feature.
+	Balanced = Profile{Name: "balanced"}
+
+	// Fast starts cheap (30 turns, low effort) and arms every escalation
+	// trigger so a struggling run restores its displaced posture: two
+	// same-tool retriable failures in a row, a second uncertain completion
+	// evaluation, a failing self-correction cycle, or a critical-risk
+	// mutation. The risk threshold is deliberately Critical, not High: the
+	// sandbox classifies EVERY shell command as at least high risk before any
+	// command analysis, so a High trigger would fire on the first `go test`
+	// of virtually any coding task and spend the one-shot on turn one.
+	// Critical marks the genuinely scary categories (destructive commands,
+	// piped installers, out-of-workspace writes, network mutations).
+	Fast = Profile{
+		Name:                          "fast",
+		MaxTurns:                      30,
+		ReasoningEffort:               "low",
+		EscalateOnToolFailureStreak:   2,
+		EscalateOnCompletionUncertain: 2,
+		EscalateOnSelfCorrectFailure:  true,
+		EscalateOnRiskyMutation:       sandbox.RiskCritical,
+	}
+
+	// Thorough doubles the default budget, asks for high effort, and arms the
+	// full post-edit verify-and-correct loop. Already the maximum posture, so
+	// it has nothing to escalate to.
+	Thorough = Profile{
+		Name:            "thorough",
+		MaxTurns:        160,
+		ReasoningEffort: "high",
+		SelfCorrect:     true,
+	}
+)
+
+var catalog = map[string]Profile{
+	Balanced.Name: Balanced,
+	Fast.Name:     Fast,
+	Thorough.Name: Thorough,
+}
+
+// Lookup resolves a profile by name, case-insensitively and ignoring
+// surrounding whitespace.
+func Lookup(name string) (Profile, bool) {
+	profile, ok := catalog[strings.ToLower(strings.TrimSpace(name))]
+	return profile, ok
+}
+
+// Names returns the catalog's profile names, sorted, for usage errors and help.
+func Names() []string {
+	names := make([]string, 0, len(catalog))
+	for name := range catalog {
+		names = append(names, name)
+	}
+	sort.Strings(names)
+	return names
+}
+
+// Policy projects the profile into the loop-facing ProfilePolicy.
+//
+// displacedMaxTurns is the turn budget this profile displaced at selection time
+// (what the run would have used without it) and becomes the escalation's
+// restore target; pass 0 when the profile did not displace the budget (e.g.
+// the user pinned --max-turns explicitly) so escalation leaves the ceiling
+// untouched. effortFilled reports whether the profile actually filled the
+// run's reasoning effort (it backs off when the user set one explicitly); the
+// displaced effort is then "" (the provider default) by construction, which
+// the escalation restores via RestoreDefaultEffort — a plain "" target would
+// mean "leave untouched".
+//
+// Profiles with no armed triggers return nil: the loop treats a nil policy as
+// "no profile" (no observation, no counters), which keeps balanced and
+// thorough runs byte-identical to the same knob values set by hand.
+func (p Profile) Policy(displacedMaxTurns int, effortFilled bool) *agent.ProfilePolicy {
+	if p.EscalateOnToolFailureStreak == 0 && p.EscalateOnCompletionUncertain == 0 &&
+		!p.EscalateOnSelfCorrectFailure && p.EscalateOnRiskyMutation == "" {
+		return nil
+	}
+	return &agent.ProfilePolicy{
+		Name: p.Name,
+		Escalate: &agent.PostureEscalation{
+			MaxTurns:              displacedMaxTurns,
+			RestoreDefaultEffort:  effortFilled,
+			OnToolFailureStreak:   p.EscalateOnToolFailureStreak,
+			OnCompletionUncertain: p.EscalateOnCompletionUncertain,
+			OnSelfCorrectFailure:  p.EscalateOnSelfCorrectFailure,
+			OnRiskyMutation:       p.EscalateOnRiskyMutation,
+		},
+	}
+}

internal/execprofile/profile_test.go

@@ -0,0 +1,131 @@
+package execprofile
+
+import (
+	"reflect"
+	"testing"
+
+	"github.com/Gitlawb/zero/internal/sandbox"
+)
+
+// The no-regression invariant of the whole feature: balanced must be the empty
+// profile (nothing but a name), so selecting it cannot change a run.
+func TestBalancedProfileIsEmpty(t *testing.T) {
+	profile, ok := Lookup("balanced")
+	if !ok {
+		t.Fatal("balanced must exist in the catalog")
+	}
+	if profile.Name != "balanced" {
+		t.Fatalf("Name = %q, want %q", profile.Name, "balanced")
+	}
+	profile.Name = ""
+	if !reflect.DeepEqual(profile, Profile{}) {
+		t.Fatalf("balanced must be zero-valued apart from its name, got %+v", profile)
+	}
+	if policy := Balanced.Policy(80, false); policy != nil {
+		t.Fatalf("balanced Policy must be nil (byte-identical loop), got %+v", policy)
+	}
+}
+
+func TestLookupIsCaseAndSpaceInsensitive(t *testing.T) {
+	for _, name := range []string{"fast", "Fast", "  FAST  "} {
+		if _, ok := Lookup(name); !ok {
+			t.Fatalf("Lookup(%q) should resolve", name)
+		}
+	}
+	if _, ok := Lookup("turbo"); ok {
+		t.Fatal("Lookup(turbo) should not resolve")
+	}
+}
+
+func TestNamesAreSorted(t *testing.T) {
+	want := []string{"balanced", "fast", "thorough"}
+	if got := Names(); !reflect.DeepEqual(got, want) {
+		t.Fatalf("Names() = %v, want %v", got, want)
+	}
+}
+
+// Escalation targets must be the displaced values only — the catalog carries
+// triggers, the call site supplies what was displaced, and nothing else may
+// appear in the escalation.
+func TestFastPolicyTargetsDisplacedValuesOnly(t *testing.T) {
+	policy := Fast.Policy(80, true)
+	if policy == nil {
+		t.Fatal("fast must arm an escalation policy")
+	}
+	if policy.Name != "fast" {
+		t.Fatalf("policy.Name = %q, want fast", policy.Name)
+	}
+	esc := policy.Escalate
+	if esc == nil {
+		t.Fatal("fast policy must carry an escalation")
+	}
+	if esc.MaxTurns != 80 {
+		t.Fatalf("Escalate.MaxTurns = %d, want the displaced 80", esc.MaxTurns)
+	}
+	if esc.ReasoningEffort != "" {
+		t.Fatalf("Escalate.ReasoningEffort = %q, want empty (displaced effort is the provider default by construction)", esc.ReasoningEffort)
+	}
+	if !esc.RestoreDefaultEffort {
+		t.Fatal("effort was profile-filled, so escalation must restore the provider default")
+	}
+	if esc.RestoreCompletionGate {
+		t.Fatal("fast does not touch the completion gate, so escalation must not either")
+	}
+	if esc.OnToolFailureStreak != Fast.EscalateOnToolFailureStreak ||
+		esc.OnCompletionUncertain != Fast.EscalateOnCompletionUncertain ||
+		esc.OnSelfCorrectFailure != Fast.EscalateOnSelfCorrectFailure ||
+		esc.OnRiskyMutation != Fast.EscalateOnRiskyMutation {
+		t.Fatalf("escalation triggers must mirror the catalog, got %+v", esc)
+	}
+}
+
+// The effort restore arms only when the profile actually filled the effort:
+// with an explicit user effort the profile backed off, so escalation must not
+// clear the user's choice.
+func TestFastPolicyExplicitEffortIsNeverRestored(t *testing.T) {
+	policy := Fast.Policy(80, false)
+	if policy == nil || policy.Escalate == nil {
+		t.Fatal("fast must still arm its triggers")
+	}
+	if policy.Escalate.RestoreDefaultEffort {
+		t.Fatal("the profile did not fill the effort, so escalation must leave it alone")
+	}
+}
+
+// A profile that did not displace the budget (explicit --max-turns pinned it)
+// must not let escalation move the ceiling at all.
+func TestFastPolicyZeroDisplacedLeavesCeilingUntouched(t *testing.T) {
+	policy := Fast.Policy(0, false)
+	if policy == nil || policy.Escalate == nil {
+		t.Fatal("fast must still arm its triggers with a zero displaced budget")
+	}
+	if policy.Escalate.MaxTurns != 0 {
+		t.Fatalf("Escalate.MaxTurns = %d, want 0 (no displaced value to restore)", policy.Escalate.MaxTurns)
+	}
+}
+
+// Thorough is already the maximum posture: no triggers, so no policy — the
+// loop must stay byte-identical to the same knobs set by hand.
+func TestThoroughPolicyIsNil(t *testing.T) {
+	if policy := Thorough.Policy(80, true); policy != nil {
+		t.Fatalf("thorough Policy must be nil, got %+v", policy)
+	}
+}
+
+// Pin the catalog's provisional values so a retune is a deliberate,
+// test-visible diff (these floors came from the Phase 0 baseline's read-class
+// evidence and are expected to move after the post-oracle-fix re-capture).
+func TestCatalogProvisionalValues(t *testing.T) {
+	if Fast.MaxTurns != 30 || Fast.ReasoningEffort != "low" || Fast.SelfCorrect {
+		t.Fatalf("fast knobs changed: %+v", Fast)
+	}
+	// Critical, not High: the sandbox classifies every shell command as at
+	// least high risk, so a High trigger would spend the one-shot escalation
+	// on the first benign `go test` of any coding task.
+	if Fast.EscalateOnRiskyMutation != sandbox.RiskCritical {
+		t.Fatalf("fast risky-mutation trigger = %q, want %q", Fast.EscalateOnRiskyMutation, sandbox.RiskCritical)
+	}
+	if Thorough.MaxTurns != 160 || Thorough.ReasoningEffort != "high" || !Thorough.SelfCorrect {
+		t.Fatalf("thorough knobs changed: %+v", Thorough)
+	}
+}

internal/mcp/oauth.go

@@ -133,6 +133,26 @@ func discoverAuthorizationServer(ctx context.Context, client *http.Client, baseU
 	}, nil
 }
 
+// validateResolvedEndpoints applies the shared https/loopback endpoint rule to
+// every non-empty endpoint in the resolved metadata — configured or discovered
+// alike — so discovery metadata can never downgrade an MCP login to an insecure
+// or attacker-controlled authorization, token, or registration endpoint.
+func validateResolvedEndpoints(metadata authServerMetadata) error {
+	for _, ep := range []struct{ kind, url string }{
+		{"authorization", metadata.AuthorizationEndpoint},
+		{"token", metadata.TokenEndpoint},
+		{"registration", metadata.RegistrationEndpoint},
+	} {
+		if strings.TrimSpace(ep.url) == "" {
+			continue
+		}
+		if err := oauth.ValidateEndpointURL(ep.url); err != nil {
+			return fmt.Errorf("mcp oauth: %s endpoint: %w", ep.kind, err)
+		}
+	}
+	return nil
+}
+
 // resolveAuthorizationServer discovers metadata and applies explicit config
 // overrides. Configured endpoints take precedence over discovered ones, and act
 // as a fallback when discovery fails or omits a value.
@@ -148,6 +168,9 @@ func resolveAuthorizationServer(ctx context.Context, client *http.Client, baseUR
 			TokenEndpoint:         strings.TrimSpace(cfg.TokenEndpoint),
 			RegistrationEndpoint:  strings.TrimSpace(cfg.RegistrationEndpoint),
 		}
+		if err := validateResolvedEndpoints(metadata); err != nil {
+			return authServerMetadata{}, err
+		}
 		return metadata, nil
 	}
 
@@ -179,6 +202,9 @@ func resolveAuthorizationServer(ctx context.Context, client *http.Client, baseUR
 	if strings.TrimSpace(metadata.TokenEndpoint) == "" {
 		return authServerMetadata{}, errors.New("no token endpoint discovered or configured")
 	}
+	if err := validateResolvedEndpoints(metadata); err != nil {
+		return authServerMetadata{}, err
+	}
 	return metadata, nil
 }
 

internal/mcp/oauth_test.go

@@ -73,6 +73,22 @@ func TestResolveEndpointsFallsBackToConfig(t *testing.T) {
 	}
 }
 
+// Discovered MCP metadata that serves an insecure endpoint must be rejected
+// before use, so discovery cannot downgrade the MCP login to an
+// attacker-controlled origin (issue #511).
+func TestResolveAuthorizationServerRejectsInsecureDiscovered(t *testing.T) {
+	mux := http.NewServeMux()
+	server := httptest.NewServer(mux)
+	defer server.Close()
+	mux.HandleFunc("/.well-known/oauth-authorization-server", func(w http.ResponseWriter, _ *http.Request) {
+		_, _ = w.Write([]byte(`{"issuer":"` + server.URL + `","token_endpoint":"` + server.URL + `/token","authorization_endpoint":"http://evil.example/authorize"}`))
+	})
+	_, err := resolveAuthorizationServer(context.Background(), server.Client(), server.URL, OAuthConfig{})
+	if err == nil || !strings.Contains(err.Error(), "authorization endpoint") {
+		t.Fatalf("err = %v, want insecure authorization endpoint rejection", err)
+	}
+}
+
 // roundTripperFunc adapts a function to http.RoundTripper so a test can
 // observe every outbound request.
 type roundTripperFunc func(*http.Request) (*http.Response, error)

internal/npmwrapper/npmwrapper_test.go

@@ -12,6 +12,54 @@ import (
 	"time"
 )
 
+// Mirror internal/cli/exec.go exit codes so wrapper doctor fallback tests assert
+// the same CLI contract as the Go doctor command.
+const (
+	wrapperExitSuccess = 0
+	wrapperExitUsage   = 2
+	wrapperExitDoctor  = 1
+)
+
+// Canonical Bun recovery copy from bin/zero.js bunRecoveryParagraph() — shared
+// by the generic missing-binary path and the doctor text fallback.
+const (
+	bunRecoveryLead        = "You installed with Bun, which does not run dependency lifecycle scripts"
+	bunPmTrustProject      = "bun pm trust @gitlawb/zero"
+	bunPmTrustGlobal       = "bun pm -g trust @gitlawb/zero"
+	bunRecoveryTrustedDeps = `"trustedDependencies": ["@gitlawb/zero"]`
+	buildFromSourceLead    = "If this platform has no prebuilt binary, build from source:"
+)
+
+func runWrapperFixture(t *testing.T, wrapperPath string, args ...string) (stdout string, stderr string, exitCode int) {
+	return runWrapperFixtureWithEnv(t, wrapperPath, nil, args...)
+}
+
+func runWrapperFixtureWithEnv(t *testing.T, wrapperPath string, extraEnv []string, args ...string) (stdout string, stderr string, exitCode int) {
+	t.Helper()
+	node := requireNode(t)
+	ctx, cancel := context.WithTimeout(context.Background(), nodeWrapperTimeout())
+	defer cancel()
+	command := nodeWrapperCommand(ctx, node, wrapperPath, args...)
+	command.Env = append(withoutEnvKey(command.Env, "ZERO_LOCAL_CONTROL_HELPERS"), "ZERO_LOCAL_CONTROL_HELPERS=")
+	command.Env = append(withoutEnvKey(command.Env, "ZERO_WRAPPER_SIMULATE_BUN"), extraEnv...)
+	var stdoutBuf, stderrBuf strings.Builder
+	command.Stdout = &stdoutBuf
+	command.Stderr = &stderrBuf
+	err := command.Run()
+	if ctx.Err() != nil {
+		t.Fatalf("wrapper timed out: %v; stdout: %s stderr: %s", ctx.Err(), stdoutBuf.String(), stderrBuf.String())
+	}
+	exitCode = wrapperExitSuccess
+	if err != nil {
+		exitErr, ok := err.(*exec.ExitError)
+		if !ok {
+			t.Fatalf("wrapper err = %v, want *exec.ExitError; stdout=%s stderr=%s", err, stdoutBuf.String(), stderrBuf.String())
+		}
+		exitCode = exitErr.ExitCode()
+	}
+	return stdoutBuf.String(), stderrBuf.String(), exitCode
+}
+
 func TestPackageBinPointsToNodeWrapper(t *testing.T) {
 	root := repoRoot(t)
 	bytes, err := os.ReadFile(filepath.Join(root, "package.json"))
@@ -393,6 +441,221 @@ func nodeArchName() string {
 	}
 }
 
+// Issue #405: `zero doctor` is the diagnostic command, so when the native
+// binary is the thing that's broken it must NOT bail with the generic wrapper
+// error; that's exactly the blind alley the bug report calls out. Instead it
+// emits a doctor-shaped FAIL line for the runtime so the user's own diagnostic
+// surfaces the real cause. We assert on the doctor-report shape (so the doctor
+// UX matches what the Go-side doctor.Format produces) and on exit 1 (a missing
+// binary is still a hard failure, not a pass).
+func TestNodeWrapperDoctorReportsMissingNativeBinaryAsDoctorFail(t *testing.T) {
+	wrapperPath := copyWrapperFixture(t)
+	stdout, stderr, exitCode := runWrapperFixture(t, wrapperPath, "doctor")
+	if exitCode != wrapperExitDoctor {
+		t.Fatalf("doctor exit = %d, want %d; stdout=%s stderr=%s", exitCode, wrapperExitDoctor, stdout, stderr)
+	}
+	if strings.TrimSpace(stderr) != "" {
+		t.Fatalf("doctor text report must go to stdout only, got stderr=%q", stderr)
+	}
+	// Doctor-shaped report, not the generic wrapper bail. Matches the shape the
+	// Go-side doctor.Format emits: a header, "Overall: <pass/fail>", then
+	// "[<status>] <id> - <message>" lines.
+	if !strings.Contains(stdout, "Zero doctor report (") {
+		t.Fatalf("doctor output should start with a doctor report header, got stdout=%q", stdout)
+	}
+	if !strings.Contains(stdout, "Overall: fail") {
+		t.Fatalf("doctor overall must be fail when the native binary is missing, got stdout=%q", stdout)
+	}
+	if !strings.Contains(stdout, "[fail] runtime.go") {
+		t.Fatalf("doctor must report a failing runtime.go check, got stdout=%q", stdout)
+	}
+	if !strings.Contains(stdout, "Native zero binary is missing next to the npm wrapper") {
+		t.Fatalf("doctor must name the actual cause (missing native binary), got stdout=%q", stdout)
+	}
+	// The actionable remedy must point at the postinstall script that would fix
+	// the install, not just "build from source".
+	if !strings.Contains(stdout, "postinstall.mjs") {
+		t.Fatalf("doctor remedy should name the postinstall script, got stdout=%q", stdout)
+	}
+	// Regression guard for the original blind-alley bug: the doctor path must
+	// NOT emit the generic wrapper bail (that's what sent users debugging the
+	// wrong thing).
+	if strings.Contains(stdout, "[zero] No native binary is available for this install") {
+		t.Fatalf("doctor must not emit the generic wrapper bail, got stdout=%q", stdout)
+	}
+}
+
+func TestNodeWrapperDoctorJSONReportsMissingNativeBinaryAsJSONFail(t *testing.T) {
+	wrapperPath := copyWrapperFixture(t)
+	stdout, stderr, exitCode := runWrapperFixture(t, wrapperPath, "doctor", "--json")
+	if exitCode != wrapperExitDoctor {
+		t.Fatalf("doctor --json exit = %d, want %d; stdout=%s stderr=%s", exitCode, wrapperExitDoctor, stdout, stderr)
+	}
+	if strings.TrimSpace(stderr) != "" {
+		t.Fatalf("doctor --json should write machine-readable output to stdout only, got stderr=%q", stderr)
+	}
+	var report struct {
+		GeneratedAt string `json:"generatedAt"`
+		OK          bool   `json:"ok"`
+		Checks      []struct {
+			ID      string         `json:"id"`
+			Label   string         `json:"label"`
+			Status  string         `json:"status"`
+			Message string         `json:"message"`
+			Details map[string]any `json:"details"`
+		} `json:"checks"`
+	}
+	if err := json.Unmarshal([]byte(stdout), &report); err != nil {
+		t.Fatalf("doctor --json stdout should be valid JSON, got %q: %v", stdout, err)
+	}
+	if report.GeneratedAt == "" {
+		t.Fatalf("doctor --json report should include generatedAt: %#v", report)
+	}
+	if report.OK {
+		t.Fatalf("doctor --json ok = true, want false: %#v", report)
+	}
+	if len(report.Checks) != 1 {
+		t.Fatalf("doctor --json checks length = %d, want 1: %#v", len(report.Checks), report.Checks)
+	}
+	check := report.Checks[0]
+	if check.ID != "runtime.go" || check.Label != "Go runtime" || check.Status != "fail" {
+		t.Fatalf("doctor --json runtime check = %#v, want failing runtime.go check", check)
+	}
+	if !strings.Contains(check.Message, "Native zero binary is missing next to the npm wrapper") {
+		t.Fatalf("doctor --json must name the actual cause, got %#v", check)
+	}
+	remedy, _ := check.Details["remedy"].(string)
+	if !strings.Contains(remedy, "postinstall.mjs") {
+		t.Fatalf("doctor --json remedy should name the postinstall script, got %#v", check.Details)
+	}
+}
+
+func TestNodeWrapperDoctorHelpShowsUsage(t *testing.T) {
+	wrapperPath := copyWrapperFixture(t)
+	for _, args := range [][]string{{"doctor", "--help"}, {"doctor", "help"}, {"doctor", "-h"}} {
+		stdout, stderr, exitCode := runWrapperFixture(t, wrapperPath, args...)
+		if exitCode != wrapperExitSuccess {
+			t.Fatalf("%v exit = %d, want %d; stdout=%s stderr=%s", args, exitCode, wrapperExitSuccess, stdout, stderr)
+		}
+		if strings.TrimSpace(stderr) != "" {
+			t.Fatalf("%v help must write to stdout only, got stderr=%q", args, stderr)
+		}
+		if !strings.Contains(stdout, "Usage:") || !strings.Contains(stdout, "zero doctor [flags]") {
+			t.Fatalf("%v help output = %q, want doctor usage text", args, stdout)
+		}
+	}
+}
+
+func TestNodeWrapperDoctorRejectsUnknownFlag(t *testing.T) {
+	wrapperPath := copyWrapperFixture(t)
+	stdout, stderr, exitCode := runWrapperFixture(t, wrapperPath, "doctor", "--bogus")
+	if exitCode != wrapperExitUsage {
+		t.Fatalf("doctor --bogus exit = %d, want %d; stdout=%s stderr=%s", exitCode, wrapperExitUsage, stdout, stderr)
+	}
+	if strings.TrimSpace(stdout) != "" {
+		t.Fatalf("invalid doctor flag should not write stdout, got %q", stdout)
+	}
+	if stderr != "[zero] unknown doctor flag \"--bogus\"\n" {
+		t.Fatalf("invalid doctor flag stderr = %q", stderr)
+	}
+}
+
+// `doctor --connectivity` (a valid doctor invocation with a trailing flag) must
+// take the same doctor-shaped path: parseDoctorArgs accepts --connectivity and
+// the missing-binary fallback still reports the runtime failure.
+func TestNodeWrapperDoctorWithFlagsStillReportsDoctorFail(t *testing.T) {
+	wrapperPath := copyWrapperFixture(t)
+	stdout, stderr, exitCode := runWrapperFixture(t, wrapperPath, "doctor", "--connectivity")
+	if exitCode != wrapperExitDoctor {
+		t.Fatalf("doctor --connectivity exit = %d, want %d; stdout=%s stderr=%s", exitCode, wrapperExitDoctor, stdout, stderr)
+	}
+	if strings.TrimSpace(stderr) != "" {
+		t.Fatalf("doctor --connectivity must write to stdout only, got stderr=%q", stderr)
+	}
+	if !strings.Contains(stdout, "[fail] runtime.go") {
+		t.Fatalf("doctor --connectivity must still emit the failing runtime.go line, got stdout=%q", stdout)
+	}
+	if strings.Contains(stdout, "[zero] No native binary is available for this install") {
+		t.Fatalf("doctor --connectivity must not fall back to the generic bail, got stdout=%q", stdout)
+	}
+}
+
+func TestNodeWrapperGenericReportsBunRecoveryWhenInstalledByBun(t *testing.T) {
+	wrapperPath := copyWrapperFixture(t)
+	_, stderr, exitCode := runWrapperFixtureWithEnv(t, wrapperPath, []string{"ZERO_WRAPPER_SIMULATE_BUN=1"}, "--version")
+	if exitCode != wrapperExitDoctor {
+		t.Fatalf("generic missing-binary exit = %d, want %d; stderr=%s", exitCode, wrapperExitDoctor, stderr)
+	}
+	assertBunRecoveryMessage(t, stderr)
+	if !strings.Contains(stderr, buildFromSourceLead) {
+		t.Fatalf("generic bun stderr should include build-from-source guidance, got %q", stderr)
+	}
+}
+
+func TestNodeWrapperDoctorReportsBunRecoveryWhenInstalledByBun(t *testing.T) {
+	wrapperPath := copyWrapperFixture(t)
+	stdout, stderr, exitCode := runWrapperFixtureWithEnv(t, wrapperPath, []string{"ZERO_WRAPPER_SIMULATE_BUN=1"}, "doctor")
+	if exitCode != wrapperExitDoctor {
+		t.Fatalf("doctor bun exit = %d, want %d; stdout=%s stderr=%s", exitCode, wrapperExitDoctor, stdout, stderr)
+	}
+	if strings.TrimSpace(stderr) != "" {
+		t.Fatalf("doctor bun report must go to stdout only, got stderr=%q", stderr)
+	}
+	if !strings.Contains(stdout, "[fail] runtime.go") {
+		t.Fatalf("doctor bun report must still fail runtime.go, got stdout=%q", stdout)
+	}
+	assertBunRecoveryMessage(t, stdout)
+	if !strings.Contains(stdout, buildFromSourceLead) {
+		t.Fatalf("doctor bun report should reuse generic build-from-source guidance, got stdout=%q", stdout)
+	}
+	if strings.Contains(stdout, "If reinstall fails") {
+		t.Fatalf("doctor bun report must not use a separate build-from-source string, got stdout=%q", stdout)
+	}
+}
+
+func TestNodeWrapperDoctorAndGenericShareBunRecoveryCopy(t *testing.T) {
+	wrapperPath := copyWrapperFixture(t)
+	simulateBun := []string{"ZERO_WRAPPER_SIMULATE_BUN=1"}
+	_, genericStderr, _ := runWrapperFixtureWithEnv(t, wrapperPath, simulateBun, "--version")
+	doctorStdout, _, _ := runWrapperFixtureWithEnv(t, wrapperPath, simulateBun, "doctor")
+	genericBun := extractBunRecoveryBlock(genericStderr)
+	doctorBun := extractBunRecoveryBlock(doctorStdout)
+	if genericBun != doctorBun {
+		t.Fatalf("bun recovery copy drift:\ngeneric=%q\ndoctor=%q", genericBun, doctorBun)
+	}
+}
+
+func assertBunRecoveryMessage(t *testing.T, output string) {
+	t.Helper()
+	if !strings.Contains(output, bunRecoveryLead) {
+		t.Fatalf("output should include bun recovery lead, got %q", output)
+	}
+	if !strings.Contains(output, bunPmTrustProject) {
+		t.Fatalf("output should include project bun pm trust guidance, got %q", output)
+	}
+	if !strings.Contains(output, bunPmTrustGlobal) {
+		t.Fatalf("output should include global bun pm trust guidance, got %q", output)
+	}
+	if !strings.Contains(output, bunRecoveryTrustedDeps) {
+		t.Fatalf("output should include trustedDependencies fallback guidance, got %q", output)
+	}
+	if !strings.Contains(output, "to your project package.json and reinstall.") {
+		t.Fatalf("output should mention package.json reinstall fallback, got %q", output)
+	}
+}
+
+func extractBunRecoveryBlock(output string) string {
+	start := strings.Index(output, bunRecoveryLead)
+	if start < 0 {
+		return ""
+	}
+	end := strings.Index(output[start:], buildFromSourceLead)
+	if end < 0 {
+		return strings.TrimSpace(output[start:])
+	}
+	return strings.TrimSpace(output[start : start+end])
+}
+
 func TestNodeWrapperLaunchesNativeBinary(t *testing.T) {
 	if runtime.GOOS == "windows" {
 		t.Skip("mock executable fixture uses a POSIX shell script")

internal/oauth/device.go

@@ -49,9 +49,9 @@ func RequestDeviceCode(ctx context.Context, client *http.Client, cfg Config, now
 	if err := validateTokenEndpoint(endpoint); err != nil {
 		return DeviceAuth{}, err
 	}
-	if client == nil {
-		client = http.DefaultClient
-	}
+	// Refuse redirects so a device-authorization redirect can't replay the
+	// client_id/client_secret POST body to an unvalidated origin.
+	client = withoutRedirects(client)
 	if now == nil {
 		now = time.Now
 	}
@@ -157,9 +157,9 @@ func pollDeviceOnce(ctx context.Context, client *http.Client, cfg Config, device
 	if err := validateTokenEndpoint(cfg.TokenEndpoint); err != nil {
 		return Token{}, err
 	}
-	if client == nil {
-		client = http.DefaultClient
-	}
+	// Refuse redirects so a poll redirect can't replay the device_code/secret
+	// POST body to an unvalidated origin.
+	client = withoutRedirects(client)
 	form := url.Values{}
 	form.Set("grant_type", deviceGrantType)
 	form.Set("device_code", deviceCode)

internal/oauth/device_test.go

@@ -2,6 +2,7 @@ package oauth
 
 import (
 	"context"
+	"errors"
 	"net/http"
 	"net/http/httptest"
 	"strings"
@@ -28,6 +29,30 @@ func TestRequestDeviceCodeSendsClientSecret(t *testing.T) {
 	}
 }
 
+func TestRequestDeviceCodeRefusesRedirect(t *testing.T) {
+	endpoint, hits := redirectTrap(t, http.StatusTemporaryRedirect) // 307
+	_, err := RequestDeviceCode(context.Background(), http.DefaultClient,
+		Config{ClientID: "c", ClientSecret: "shh", DeviceAuthorizationEndpoint: endpoint}, nil)
+	if !errors.Is(err, ErrUnsafeRedirect) {
+		t.Fatalf("RequestDeviceCode err = %v, want ErrUnsafeRedirect", err)
+	}
+	if n := hits(); n != 0 {
+		t.Fatalf("attacker received %d request(s) — client_secret replayed", n)
+	}
+}
+
+func TestPollDeviceOnceRefusesRedirect(t *testing.T) {
+	endpoint, hits := redirectTrap(t, http.StatusPermanentRedirect) // 308
+	_, err := pollDeviceOnce(context.Background(), http.DefaultClient,
+		Config{ClientID: "c", ClientSecret: "shh", TokenEndpoint: endpoint}, "device-code", nil)
+	if !errors.Is(err, ErrUnsafeRedirect) {
+		t.Fatalf("pollDeviceOnce err = %v, want ErrUnsafeRedirect", err)
+	}
+	if n := hits(); n != 0 {
+		t.Fatalf("attacker received %d request(s) — device_code/secret replayed", n)
+	}
+}
+
 func TestRequestDeviceCode(t *testing.T) {
 	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
 		_, _ = w.Write([]byte(`{"device_code":"dc","user_code":"WXYZ-1234","verification_uri":"https://x/dev","verification_uri_complete":"https://x/dev?c=WXYZ","expires_in":600,"interval":3}`))

internal/oauth/flow.go

@@ -39,6 +39,13 @@ func BuildAuthorizationURL(cfg Config, pkce PKCE, state, redirectURI string, ext
 	if endpoint == "" {
 		return "", errors.New("oauth: no authorization endpoint configured")
 	}
+	// Backstop: validate the authorization endpoint at the shared choke point
+	// both the provider and MCP flows build their browser URL through, so a
+	// discovery-downgraded endpoint can never open in the browser even if a
+	// merge site missed it.
+	if err := ValidateEndpointURL(endpoint); err != nil {
+		return "", err
+	}
 	parsed, err := url.Parse(endpoint)
 	if err != nil {
 		return "", fmt.Errorf("oauth: parse authorization endpoint: %w", err)
@@ -83,13 +90,15 @@ func isReservedAuthParam(key string) bool {
 	}
 }
 
-// validateTokenEndpoint refuses to send a credential to a token endpoint that is
-// not https, unless it is a loopback host (mirrors oauth2-client.js
-// validateTokenEndpointURL). This prevents leaking codes/tokens over cleartext.
-func validateTokenEndpoint(endpoint string) error {
+// ValidateEndpointURL refuses an OAuth endpoint that is not https, unless it is
+// a loopback host (mirrors oauth2-client.js validateTokenEndpointURL). Every
+// credential-bearing endpoint — configured OR learned from discovery — must
+// pass this single rule, so discovery metadata can never downgrade a login to
+// cleartext or redirect it to an attacker-controlled http origin.
+func ValidateEndpointURL(endpoint string) error {
 	parsed, err := url.Parse(trimmed(endpoint))
 	if err != nil || parsed.Host == "" {
-		return fmt.Errorf("oauth: invalid token endpoint %q", endpoint)
+		return fmt.Errorf("oauth: invalid endpoint %q", endpoint)
 	}
 	if parsed.Scheme == "https" {
 		return nil
@@ -100,6 +109,30 @@ func validateTokenEndpoint(endpoint string) error {
 	return fmt.Errorf("%w: %s", ErrInsecureTokenEndpoint, parsed.Scheme+"://"+parsed.Host)
 }
 
+// validateTokenEndpoint checks a token endpoint against the shared endpoint rule
+// (kept as a named helper for the token-exchange and device call sites). This
+// prevents leaking codes/tokens over cleartext.
+func validateTokenEndpoint(endpoint string) error {
+	return ValidateEndpointURL(endpoint)
+}
+
+// withoutRedirects returns a shallow copy of client whose redirect policy
+// refuses to follow ANY redirect. A credential-bearing OAuth POST (token
+// exchange/refresh, device authorization, device-token poll) must never let a
+// 307/308 replay its form body — codes, PKCE verifiers, refresh tokens, client
+// secrets — to a target that was never endpoint-validated. The caller's client
+// is left unmodified.
+func withoutRedirects(client *http.Client) *http.Client {
+	if client == nil {
+		client = http.DefaultClient
+	}
+	copied := *client
+	copied.CheckRedirect = func(*http.Request, []*http.Request) error {
+		return ErrUnsafeRedirect
+	}
+	return &copied
+}
+
 func isLoopbackHost(host string) bool {
 	if host == "localhost" {
 		return true
@@ -160,9 +193,9 @@ func PostToken(ctx context.Context, client *http.Client, tokenEndpoint string, f
 	if err := validateTokenEndpoint(tokenEndpoint); err != nil {
 		return Token{}, err
 	}
-	if client == nil {
-		client = http.DefaultClient
-	}
+	// Refuse redirects so a 307/308 from the token endpoint can't replay this
+	// credential-bearing POST body to another (unvalidated) origin.
+	client = withoutRedirects(client)
 	if now == nil {
 		now = time.Now
 	}