feat(http-client): request bodies from DTOs in other modules, header completion

Generating a request from a Spring mapping looked for the @RequestBody
type only beside the controller or in the same source root, so a DTO in
another Maven module came out as {}. Types not found there are now looked
up in the project index, in the imported (or same / wildcard-imported)
package, and the fields of their superclasses are included.

Header names complete on the lines after a request line, and values of
the common headers (Content-Type, Accept, Authorization, …) after the
colon. Requests opened from an endpoint use its module's server address
instead of a fixed localhost:8080.

.github/workflows/release-build.yml

@@ -151,6 +151,13 @@ jobs:
           $hash = (Get-FileHash $asset -Algorithm SHA256).Hash.ToLower()
           "$hash  $asset" | Out-File -Encoding ascii "$asset.sha256"
           gh release upload $env:TAG $asset "$asset.sha256" --clobber
+          if ($LASTEXITCODE -ne 0) { exit $LASTEXITCODE }
+          if ($env:TAURI_SIGNING_PRIVATE_KEY) {
+            pnpm exec tauri signer sign --app-version $version $asset
+            if ($LASTEXITCODE -ne 0) { exit $LASTEXITCODE }
+            gh release upload $env:TAG "$asset.sig" --clobber
+            if ($LASTEXITCODE -ne 0) { exit $LASTEXITCODE }
+          }
 
   # The remote development server, per host platform it can run on. The desktop
   # app downloads the one for the host (ide-tools `server`) and installs it over SSH.
@@ -233,6 +240,8 @@ jobs:
               [/_x64\.app\.tar\.gz$/, ["darwin-x86_64", "darwin-x86_64-app"]],
               ...windows("aarch64", /_arm64_en-US\.msi$/, /_arm64-setup\.exe$/),
               ...windows("x86_64", /_x64_en-US\.msi$/, /_x64-setup\.exe$/),
+              [/_windows_arm64_portable\.zip$/, ["windows-aarch64-portable"]],
+              [/_windows_x64_portable\.zip$/, ["windows-x86_64-portable"]],
             ];
             const platforms = {};
             for (const sig of sigs) {

crates/ide-build/src/maven.rs

@@ -1680,6 +1680,15 @@ pub enum PomGotoKind {
     ManagedDependency,
     /// A `<pluginManagement>` entry providing the plugin's version.
     ManagedPlugin,
+    /// The POM of the artifact itself: a project module's, else the local repository's.
+    ArtifactPom,
+}
+
+/// A Maven project of the workspace, for going to a dependency on it.
+pub struct ModulePom {
+    pub group_id: String,
+    pub artifact_id: String,
+    pub pom: PathBuf,
 }
 
 /// Byte offset of `pos` (0-based line / UTF-16 column), clamped to `text`.
@@ -1759,6 +1768,20 @@ fn coordinates(e: &Element, props: &HashMap<String, String>) -> Option<(String,
 /// the local repository when it is not in the project). `None` when there is no
 /// resolvable declaration here.
 pub fn goto_declaration(text: &str, path: &Path, pos: Pos, local_repo: Option<PathBuf>) -> Option<PomGoto> {
+    goto_declaration_in(text, path, pos, local_repo, Vec::new)
+}
+
+/// [`goto_declaration`], where a `<parent>` and a dependency or plugin whose version no
+/// management entry provides (or a management entry itself) go to the artifact's own
+/// POM: the project module among `modules` with its coordinates, else the local
+/// repository's POM of its version.
+pub fn goto_declaration_in(
+    text: &str,
+    path: &Path,
+    pos: Pos,
+    local_repo: Option<PathBuf>,
+    modules: impl FnOnce() -> Vec<ModulePom>,
+) -> Option<PomGoto> {
     let root = xml::parse(text).filter(|e| e.name == "project")?;
     let at = offset_at(text, pos);
     if let Some((name, _, _)) = property_ref_at(text, at)
@@ -1769,15 +1792,56 @@ pub fn goto_declaration(text: &str, path: &Path, pos: Pos, local_repo: Option<Pa
     // A `<dependency>` / `<plugin>` in a declaration position: its version may come
     // from a management entry of this POM or an ancestor's.
     let elements = element_path(&root, at);
-    let e = elements.iter().rev().find(|e| e.name == "dependency" || e.name == "plugin")?;
-    if elements.iter().any(|a| a.name == "dependencyManagement" || a.name == "pluginManagement") {
-        return None; // Management entries are declarations; there is nothing to go to.
+    if elements.get(1).is_some_and(|e| e.name == "parent") {
+        let chain = parent_chain(path, text, local_repo);
+        let (pom, parent_text) = chain.get(1)?;
+        let label = elements[1].text_of("artifactId").unwrap_or_default();
+        return Some(pom_goto(pom.clone(), parent_text, label));
     }
-    let kind = match e.name.as_str() {
-        "dependency" => PomGotoKind::ManagedDependency,
-        _ => PomGotoKind::ManagedPlugin,
-    };
-    managed_target(text, path, e, kind, local_repo)
+    let e = elements.iter().rev().find(|e| e.name == "dependency" || e.name == "plugin")?;
+    // A management entry declares the version: it goes to the artifact (a BOM import, say).
+    if !elements.iter().any(|a| a.name == "dependencyManagement" || a.name == "pluginManagement") {
+        let kind = match e.name.as_str() {
+            "dependency" => PomGotoKind::ManagedDependency,
+            _ => PomGotoKind::ManagedPlugin,
+        };
+        if let Some(found) = managed_target(text, path, e, kind, local_repo.clone()) {
+            return Some(found);
+        }
+    }
+    artifact_target(text, path, e, local_repo, modules)
+}
+
+/// The artifact's own POM for a dependency or plugin element `e`.
+fn artifact_target(
+    text: &str,
+    path: &Path,
+    e: &Element,
+    local_repo: Option<PathBuf>,
+    modules: impl FnOnce() -> Vec<ModulePom>,
+) -> Option<PomGoto> {
+    let mut resolver = Resolver::new(local_repo.clone(), &[]);
+    let chain = parent_chain(path, text, local_repo);
+    let props = properties_at(&mut resolver, &chain, 0);
+    let (group, artifact) = coordinates(e, &props)?;
+    let label = format!("{group}:{artifact}");
+    if let Some(module) = modules().into_iter().find(|m| m.group_id == group && m.artifact_id == artifact) {
+        let module_text = xml::read_text(&module.pom)?;
+        return Some(pom_goto(module.pom, &module_text, label));
+    }
+    let version = interpolate(&e.text_of("version")?, &props);
+    let pom = resolver.repo_pom(&group, &artifact, &version)?;
+    let pom_text = xml::read_text(&pom)?;
+    Some(pom_goto(pom, &pom_text, label))
+}
+
+/// The POM at `path` as a target, at its `<artifactId>`.
+fn pom_goto(path: PathBuf, text: &str, label: String) -> PomGoto {
+    let range = xml::parse(text)
+        .filter(|e| e.name == "project")
+        .and_then(|root| root.child("artifactId").map(|a| range_of(text, a)))
+        .unwrap_or_default();
+    PomGoto { path, range, kind: PomGotoKind::ArtifactPom, label }
 }
 
 /// The parent POMs of the POM in `text` at `path`, child-first (its `<parent>` refs,
@@ -3087,9 +3151,9 @@ mod tests {
         let text = std::fs::read_to_string(&path).unwrap();
         // The property is declared nowhere along the chain.
         assert_eq!(goto_declaration(&text, &path, at(&text, "${missing.key}"), None), None);
-        // The dependency names its own version: it is the declaration.
+        // The dependency names its own version and no local repository has its POM.
         assert_eq!(goto_declaration(&text, &path, at(&text, "<artifactId>other-lib"), None), None);
-        // A management entry is a declaration itself, not a reference.
+        // A management entry declares the version; its artifact's POM is not at hand either.
         let parent_path = tmp.path().join("pom.xml");
         let parent_text = std::fs::read_to_string(&parent_path).unwrap();
         assert_eq!(
@@ -3101,6 +3165,72 @@ mod tests {
         assert_eq!(goto_declaration("<project></project>", &path, Pos::new(0, 3), None), None);
     }
 
+    #[test]
+    fn artifacts_go_to_their_own_pom_in_the_project_or_the_local_repository() {
+        let tmp = tempfile::tempdir().unwrap();
+        let repo = tmp.path().join("repo");
+        let bom_dir = repo.join("com/alibaba/cloud/spring-cloud-alibaba-dependencies/2.2.6.RELEASE");
+        std::fs::create_dir_all(&bom_dir).unwrap();
+        let bom = "<project>\n  <groupId>com.alibaba.cloud</groupId>\n  <artifactId>spring-cloud-alibaba-dependencies</artifactId>\n</project>";
+        std::fs::write(bom_dir.join("spring-cloud-alibaba-dependencies-2.2.6.RELEASE.pom"), bom).unwrap();
+        let parent = format!(
+            r#"{PARENT_HEADER}<properties><alibaba.version>2.2.6.RELEASE</alibaba.version></properties>
+<dependencyManagement>
+  <dependencies>
+    <dependency>
+      <groupId>com.alibaba.cloud</groupId>
+      <artifactId>spring-cloud-alibaba-dependencies</artifactId>
+      <version>${{alibaba.version}}</version>
+      <type>pom</type>
+      <scope>import</scope>
+    </dependency>
+  </dependencies>
+</dependencyManagement>
+</project>"#
+        );
+        let child = format!(
+            r#"{CHILD_HEADER}<dependencies>
+  <dependency>
+    <groupId>com.example</groupId>
+    <artifactId>core</artifactId>
+    <version>1.0</version>
+  </dependency>
+</dependencies>
+</project>"#
+        );
+        write_parent_child(tmp.path(), &parent, &child);
+        let core = tmp.path().join("core/pom.xml");
+        std::fs::create_dir_all(core.parent().unwrap()).unwrap();
+        std::fs::write(
+            &core,
+            "<project>\n  <groupId>com.example</groupId>\n  <artifactId>core</artifactId>\n</project>",
+        )
+        .unwrap();
+        let modules =
+            || vec![ModulePom { group_id: "com.example".into(), artifact_id: "core".into(), pom: core.clone() }];
+
+        // A BOM import in <dependencyManagement> opens the BOM from the local repository.
+        let parent_path = tmp.path().join("pom.xml");
+        let parent_text = std::fs::read_to_string(&parent_path).unwrap();
+        let at_bom = at(&parent_text, "spring-cloud-alibaba-dependencies<");
+        let goto = goto_declaration_in(&parent_text, &parent_path, at_bom, Some(repo.clone()), modules).unwrap();
+        assert_eq!(goto.path, bom_dir.join("spring-cloud-alibaba-dependencies-2.2.6.RELEASE.pom"));
+        assert_eq!(goto.kind, PomGotoKind::ArtifactPom);
+        assert_eq!(goto.range.start, pos_at(bom, bom.find("<artifactId>").unwrap()));
+
+        // A dependency on a project module opens the module's POM.
+        let path = tmp.path().join("app/pom.xml");
+        let text = std::fs::read_to_string(&path).unwrap();
+        let goto =
+            goto_declaration_in(&text, &path, at(&text, "core</artifactId>"), Some(repo.clone()), modules).unwrap();
+        assert_eq!((goto.path.as_path(), goto.label.as_str()), (core.as_path(), "com.example:core"));
+
+        // The <parent> section opens the parent POM.
+        let goto = goto_declaration_in(&text, &path, at(&text, "parent</artifactId>"), Some(repo), modules).unwrap();
+        assert_eq!(goto.path, canon(&parent_path));
+        assert_eq!(goto.kind, PomGotoKind::ArtifactPom);
+    }
+
     #[test]
     fn a_property_reference_after_non_ascii_text_is_still_found() {
         let text = format!(

crates/ide-clipboard/src/lib.rs

@@ -27,6 +27,13 @@ pub fn set_text(text: &str, owner: usize) -> std::io::Result<()> {
     imp::set_text(text, owner)
 }
 
+/// The clipboard's plain text, None when it holds none. macOS only (main thread);
+/// Linux reads it asynchronously through GTK in the app, Windows through the WebView.
+#[cfg(target_os = "macos")]
+pub fn text() -> Option<String> {
+    imp::text()
+}
+
 /// Size of `DROPFILES`: `pFiles`, `pt` (two `LONG`s), `fNC`, `fWide`.
 const HEADER: usize = 20;
 
@@ -373,6 +380,14 @@ mod imp {
         })
     }
 
+    pub fn text() -> Option<String> {
+        debug_assert!(MainThreadMarker::new().is_some(), "NSPasteboard access requires the main thread");
+        autoreleasepool(|_| {
+            // SAFETY: the type is an AppKit constant, valid for the process' lifetime.
+            NSPasteboard::generalPasteboard().stringForType(unsafe { NSPasteboardTypeString }).map(|s| s.to_string())
+        })
+    }
+
     pub fn set_text(text: &str, _owner: usize) -> std::io::Result<()> {
         debug_assert!(MainThreadMarker::new().is_some(), "NSPasteboard access requires the main thread");
         autoreleasepool(|_| {

crates/ide-core/src/event.rs

@@ -8,13 +8,18 @@
 use crate::{DebugSessionId, Diagnostic, DocId, RunId, ServerId, TaskId, TerminalId, TextChange};
 use serde::{Deserialize, Serialize};
 use specta::Type;
+use std::collections::BTreeMap;
 use std::sync::Arc;
 
+/// What a built-in MCP tool asks the project window for. `AgentRun` runs `command` (a shell
+/// line) in the Run tool window's agent tab `name`, on pipes, answered once the process
+/// started or failed to.
 #[derive(Clone, Debug, Serialize, Deserialize, Type)]
 #[serde(tag = "type", rename_all = "camelCase", rename_all_fields = "camelCase")]
 pub enum McpUiRequest {
     Confirm { client: String, tool: String, subject: String, project: String, detail: Option<String> },
     OpenFile { path: crate::IpcPath, line: Option<u32>, column: Option<u32> },
+    AgentRun { name: String, command: String, cwd: crate::IpcPath, env: BTreeMap<String, String> },
 }
 
 #[derive(Clone, Debug, Serialize, Deserialize, Type)]

crates/ide-core/src/output_encoding.rs

@@ -76,7 +76,8 @@ fn decode_tool_output_with_code_page(bytes: &[u8], code_page: u32) -> String {
     text
 }
 
-fn encoding_for_code_page(cp: u32) -> Option<&'static encoding_rs::Encoding> {
+/// The `encoding_rs` encoding of a Windows code page, when it has one.
+pub fn encoding_for_code_page(cp: u32) -> Option<&'static encoding_rs::Encoding> {
     Some(match cp {
         65001 => encoding_rs::UTF_8,
         936 => encoding_rs::GBK,
@@ -101,6 +102,56 @@ fn encoding_for_code_page(cp: u32) -> Option<&'static encoding_rs::Encoding> {
     })
 }
 
+/// The code page Windows console programs write to a pipe in: the OEM code page (GBK on a
+/// Chinese system, Shift_JIS on a Japanese one, EUC-KR on a Korean one, 437 / 850 / 866…
+/// elsewhere). `None` when it is UTF-8 (Windows' "Use Unicode UTF-8" option) or off Windows.
+pub fn console_code_page() -> Option<u32> {
+    #[cfg(windows)]
+    {
+        // SAFETY: GetOEMCP is an argument-less query with no preconditions.
+        let cp = unsafe { windows_sys::Win32::Globalization::GetOEMCP() };
+        (cp != 65001).then_some(cp)
+    }
+    #[cfg(not(windows))]
+    {
+        None
+    }
+}
+
+/// Whether every character of code page `cp` is one byte, so text in it can be decoded
+/// piece by piece.
+#[cfg(windows)]
+pub fn is_single_byte_code_page(cp: u32) -> bool {
+    use windows_sys::Win32::Globalization::{CPINFO, GetCPInfo};
+    // SAFETY: CPINFO is plain data, which GetCPInfo fills in.
+    unsafe {
+        let mut info: CPINFO = std::mem::zeroed();
+        GetCPInfo(cp, &mut info) != 0 && info.MaxCharSize == 1
+    }
+}
+
+/// `bytes` in code page `cp`, decoded by Windows (for the code pages `encoding_rs` lacks,
+/// like the OEM pages 437, 850 or 852).
+#[cfg(windows)]
+pub fn decode_code_page(bytes: &[u8], cp: u32) -> String {
+    use windows_sys::Win32::Globalization::MultiByteToWideChar;
+    let Ok(len) = i32::try_from(bytes.len()) else {
+        return String::from_utf8_lossy(bytes).into_owned();
+    };
+    if len == 0 {
+        return String::new();
+    }
+    // SAFETY: `bytes` holds `len` bytes; no output buffer asks for the length needed.
+    let needed = unsafe { MultiByteToWideChar(cp, 0, bytes.as_ptr(), len, std::ptr::null_mut(), 0) };
+    if needed <= 0 {
+        return String::from_utf8_lossy(bytes).into_owned();
+    }
+    let mut wide = vec![0u16; needed as usize];
+    // SAFETY: `wide` holds `needed` units.
+    let written = unsafe { MultiByteToWideChar(cp, 0, bytes.as_ptr(), len, wide.as_mut_ptr(), needed) };
+    String::from_utf16_lossy(&wide[..written.max(0) as usize])
+}
+
 const STD_PROPERTIES: &[&str] = &["stdout.encoding", "stderr.encoding", "sun.stdout.encoding", "sun.stderr.encoding"];
 const FILE_ENCODING: &str = "file.encoding";
 const TOOL_OPTIONS: &str = "JAVA_TOOL_OPTIONS";

crates/ide-core/src/settings.rs

@@ -288,7 +288,7 @@ pub enum NewTaskApprovals {
 }
 
 /// Agents › MCP Server: agents use the IDE's built-in tools.
-#[derive(Clone, Debug, Default, PartialEq, Eq, Serialize, Deserialize, Type)]
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize, Type)]
 #[serde(default, rename_all = "camelCase")]
 pub struct McpServerSettings {
     /// Serve the tools on 127.0.0.1 while the IDE runs.
@@ -296,6 +296,16 @@ pub struct McpServerSettings {
     /// Run the tools that change the project or start processes without asking first
     /// (IDEA's brave mode). Read from the IDE's own settings only, never a project's.
     pub run_without_confirmation: bool,
+    /// Finished agent tabs (`run_command`) the Run tool window shows; older ones are archived.
+    pub agent_tab_limit: u32,
+    /// Archived agent tabs kept; older ones are closed.
+    pub agent_archive_limit: u32,
+}
+
+impl Default for McpServerSettings {
+    fn default() -> Self {
+        Self { enabled: false, run_without_confirmation: false, agent_tab_limit: 1, agent_archive_limit: 999 }
+    }
 }
 
 /// Absent profiles retain automatic discovery for existing projects.

crates/ide-extension/src/manifest.rs

@@ -34,7 +34,7 @@ use std::path::{Component, Path, PathBuf};
 
 pub const MANIFEST_FILE: &str = "plugin.toml";
 /// The plugin API (engine) version this host implements.
-pub const ENGINE_VERSION: &str = "1.6.0";
+pub const ENGINE_VERSION: &str = "1.7.0";
 /// The 0.1 API, still accepted for contribution-only packages and 0.1 components.
 pub const LEGACY_API: &str = "0.1";
 /// Marketplace categories, in the order they are shown.

crates/ide-host/src/lib.rs

@@ -60,6 +60,8 @@ pub struct Host {
     plugin_host: RwLock<std::sync::Weak<plugins::PluginHost>>,
     pub mcp_reports: mcp::Reports,
     pub mcp_requests: mcp::Requests,
+    /// Commands agents run in the Run tool window (`run_command`).
+    pub mcp_agent_runs: mcp::AgentRuns,
     pub trust: trust::TrustStore,
     pub(crate) mcp_approvals: Arc<trust::McpServerApprovals>,
     pub config_dir: PathBuf,
@@ -141,6 +143,7 @@ impl Host {
             mcp_executable: RwLock::default(),
             mcp_reports: Default::default(),
             mcp_requests: Default::default(),
+            mcp_agent_runs: Default::default(),
             trust: trust::TrustStore::load(&config_dir, &data_dir),
             mcp_approvals: Arc::new(trust::McpServerApprovals::load(&data_dir)),
             proxy_password: ide_ssh::secrets::SecretFile::new(data_dir.join("proxy-password.json")),
@@ -269,6 +272,7 @@ impl Host {
     fn begin_close(&self, window: &str) -> Option<std::thread::JoinHandle<()>> {
         self.mcp_reports.forget_window(window);
         self.mcp_requests.forget_window(window);
+        self.mcp_agent_runs.forget_window(window);
         self.external_logs.write().remove(self.owner_window(window));
         for request in self.project_requests.write().remove(self.owner_window(window)).unwrap_or_default() {
             self.cancel_request(request);

crates/ide-host/src/mcp/check.rs

@@ -0,0 +1,176 @@
+//! `check_files`: fresh diagnostics from the language servers right after an edit, and why a
+//! file could not be checked (no server for it, not installed, crashed, misconfigured…).
+
+use super::editors::problem;
+use crate::mcp::run::timeout;
+use crate::mcp::tool::{Call, Output, Param, ParamType, Tool};
+use ide_core::{IdeError, IdeResult, Severity};
+use ide_lsp::DocumentCheck;
+use serde_json::{Value, json};
+use std::path::PathBuf;
+use std::time::{Duration, Instant};
+
+const DEFAULT_TIMEOUT_MS: usize = 30_000;
+const MAX_FILES: usize = 20;
+
+pub fn check_files() -> Tool {
+    Tool::new(
+        "check_files",
+        &format!(
+            "Checks files with the language servers now and returns their problems: call it after changing files \
+(with any tool, inside or outside the IDE). Each file is synced from disk and saved to its servers, so checks that \
+run on save (rust-analyzer's cargo check) run too; then the call waits until every server answered for the current \
+text and finished the work it started, up to `timeout` milliseconds (default {DEFAULT_TIMEOUT_MS}) for all files. \
+Unlike get_file_problems, this is a fresh analysis, before the inspection profile's filtering.
+
+Per file, `status` says what the problems are worth:
+- checked: every server answered; `problems` is complete (empty means no problems).
+- incomplete: some server was still analysing when the wait ended, or could not check; call again or raise `timeout`.
+- serverUnavailable: no server could check. `servers` gives each one's `status` (missing: not installed; \
+misconfigured; crashed; starting: did not finish starting) and `message`; tell the user, since the IDE has to be \
+fixed (Settings › Languages & Frameworks › Language Servers), and check another way meanwhile (a build or a compiler).
+- noLanguageServer: no language server is configured for this kind of file.
+- untrusted: language servers don't run in an untrusted project.
+- failed: the file could not be opened (`error`).
+`unsavedInEditor` is true when the file has unsaved changes in the IDE: the problems are for the editor's text, not \
+the file on disk. Lines and UTF-16 columns are 1-based."
+        ),
+        |call| async move {
+            let raw = call.str_list("filePaths")?;
+            if raw.is_empty() {
+                return Err(IdeError::invalid("filePaths must name at least one file"));
+            }
+            if raw.len() > MAX_FILES {
+                return Err(IdeError::invalid(format!("at most {MAX_FILES} files at a time")));
+            }
+            let errors_only = call.flag("errorsOnly", true)?;
+            let limit = timeout(&call, DEFAULT_TIMEOUT_MS)?;
+            let mut paths = Vec::new();
+            for p in raw {
+                paths.push(call.resolve_readable(&p).await?);
+            }
+            let checks = paths.into_iter().map(|path| check_one(&call, path, limit, errors_only));
+            let files = futures::future::join_all(checks).await;
+            Output::json(json!({ "files": files }))
+        },
+    )
+    .param(Param::required("filePaths", ParamType::StringList, "Files to check, relative to the project root"))
+    .param(Param::optional(
+        "errorsOnly",
+        ParamType::Boolean,
+        "Whether to return only errors (default) or warnings and hints too",
+    ))
+    .param(Param::optional("timeout", ParamType::Integer, "Milliseconds to wait for the servers at most"))
+}
+
+async fn check_one(call: &Call, path: PathBuf, limit: Duration, errors_only: bool) -> Value {
+    let mut out = json!({ "filePath": call.display(&path) });
+    if !call.project().is_trusted() {
+        out["status"] = "untrusted".into();
+        return out;
+    }
+    match check(call, &path, limit).await {
+        Ok((check, dirty, text)) => {
+            let servers: Vec<Value> = check
+                .servers
+                .iter()
+                .map(|s| {
+                    let mut v = json!({ "name": s.name, "status": s.status, "checked": s.checked });
+                    if let Some(m) = &s.message {
+                        v["message"] = m.clone().into();
+                    }
+                    if s.incomplete {
+                        v["incomplete"] = true.into();
+                    }
+                    if let Some(e) = &s.error {
+                        v["error"] = e.clone().into();
+                    }
+                    v
+                })
+                .collect();
+            out["status"] = file_status(&check).into();
+            out["problems"] = check
+                .diagnostics
+                .into_iter()
+                .filter(|d| !errors_only || d.severity == Severity::Error)
+                .map(|d| problem(d, &text))
+                .collect::<Vec<_>>()
+                .into();
+            out["servers"] = servers.into();
+            if dirty {
+                out["unsavedInEditor"] = true.into();
+            }
+        }
+        Err(e) => {
+            out["status"] = "failed".into();
+            out["error"] = e.message.into();
+        }
+    }
+    out
+}
+
+fn file_status(check: &DocumentCheck) -> &'static str {
+    if check.servers.is_empty() {
+        "noLanguageServer"
+    } else if !check.servers.iter().any(|s| s.checked) {
+        "serverUnavailable"
+    } else if check.servers.iter().all(|s| s.checked && !s.incomplete) {
+        "checked"
+    } else {
+        "incomplete"
+    }
+}
+
+/// The check of `path`, whether it has unsaved changes in the IDE, and its text.
+async fn check(call: &Call, path: &std::path::Path, limit: Duration) -> IdeResult<(DocumentCheck, bool, String)> {
+    let project = call.project().clone();
+    let docs = project.documents.clone();
+    let p = path.to_owned();
+    let at = Instant::now();
+    // Synced now: the file watcher's reload of a change made outside the IDE may not have run.
+    let (doc, changed, dirty) = call
+        .host()
+        .blocking(move || {
+            let before = docs.by_path(&p).and_then(|d| docs.version(d).ok().map(|v| (d, v)));
+            docs.on_disk_changed(std::slice::from_ref(&p));
+            let doc = docs.open(&p)?.id;
+            let changed = before.is_none_or(|(d, v)| d != doc || docs.version(d).is_ok_and(|now| now != v));
+            Ok((doc, changed, docs.is_dirty(doc).unwrap_or(false)))
+        })
+        .await?;
+    let result = project.lsp.check_document(doc, changed.then_some(at), limit, &call.cancel).await;
+    let text = project.documents.text_snapshot(doc).map(|t| t.text).unwrap_or_default();
+    let docs = project.documents.clone();
+    let _ = call
+        .host()
+        .blocking(move || {
+            docs.close(doc);
+            Ok(())
+        })
+        .await;
+    Ok((result?, dirty, text))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use ide_core::event::ServerStatus;
+    use ide_lsp::CheckedServer;
+
+    fn server(status: ServerStatus, checked: bool, incomplete: bool) -> CheckedServer {
+        CheckedServer { name: "s".into(), status, message: None, checked, incomplete, error: None }
+    }
+
+    #[test]
+    fn statuses_say_whether_the_problems_are_complete() {
+        let check = |servers| file_status(&DocumentCheck { diagnostics: Vec::new(), servers });
+        assert_eq!(check(vec![]), "noLanguageServer");
+        assert_eq!(check(vec![server(ServerStatus::Missing, false, false)]), "serverUnavailable");
+        assert_eq!(check(vec![server(ServerStatus::Ready, true, false)]), "checked");
+        assert_eq!(check(vec![server(ServerStatus::Busy, true, true)]), "incomplete");
+        assert_eq!(
+            check(vec![server(ServerStatus::Ready, true, false), server(ServerStatus::Crashed, false, false)]),
+            "incomplete"
+        );
+    }
+}

crates/ide-host/src/mcp/editors.rs

@@ -65,7 +65,7 @@ async fn current_file(call: Call) -> IdeResult<Output> {
     })
 }
 
-fn problem(d: Diagnostic, text: &str) -> Value {
+pub(super) fn problem(d: Diagnostic, text: &str) -> Value {
     json!({
         "severity": d.severity, "description": d.message,
         "lineContent": text.lines().nth(d.range.start.line as usize).unwrap_or_default(),

crates/ide-host/src/mcp/files.rs

@@ -30,9 +30,14 @@ fn read_file() -> Tool {
         "Reads a file in the project directory or from any project dependency or other project source root.
 Can read text sources inside jar/zip archives; compiled class files are not decompiled.
 Returns numbered lines (1-indexed) as text.
-By default, reads up to 2000 lines starting from the beginning of the file.
+By default, reads up to 2000 lines starting from the beginning of the file; a longer file keeps its first and last
+lines with a `…N lines truncated…` marker between them.
+With `offset` or `limit`, returns exactly lines `offset` to `offset + limit - 1` (fewer at the end of the file),
+followed by `…N more lines; read on with offset=M…` when the file goes on.
 The maximum accepted limit is 5000 lines.",
         |call| async move {
+            // An explicit range is read as asked; the default read of a whole file keeps its head and tail.
+            let window = call.opt_i64("offset")?.is_some() || call.opt_i64("limit")?.is_some();
             let offset = positive(&call, "offset", 1)?;
             let limit = positive(&call, "limit", DEFAULT_READ_LIMIT)?;
             if limit > MAX_READ_LIMIT {
@@ -50,7 +55,7 @@ The maximum accepted limit is 5000 lines.",
                 )));
             }
             let text = crate::ops::fs::read_text(&call.host(), call.window(), path).await?;
-            Ok(Output::text(render_slice(&text, offset as usize, limit as usize)?))
+            Ok(Output::text(render_slice(&text, offset as usize, limit as usize, window)?))
         },
     )
     .param(Param::required("file_path", ParamType::String, util::FILE_PATH_DESCRIPTION))
@@ -70,10 +75,12 @@ fn positive(call: &Call, name: &str, default: i64) -> IdeResult<i64> {
     }
 }
 
-/// Lines `start..` of `text` as `L<n>: <line>`; when more than `max_lines` remain, the first
-/// and the last halves of the budget with a `…N lines truncated…` marker between them.
+/// Lines `start..` of `text` as `L<n>: <line>`, at most `max_lines` of them. A `window` is
+/// exactly the lines from `start` on, then how many lines remain; otherwise, when more than
+/// `max_lines` remain, the first and the last halves of the budget with a `…N lines truncated…`
+/// marker between them.
 /// Lines are the editor's: a trailing line break starts an empty last line.
-fn render_slice(text: &str, start: usize, max_lines: usize) -> IdeResult<String> {
+fn render_slice(text: &str, start: usize, max_lines: usize, window: bool) -> IdeResult<String> {
     let lines: Vec<&str> = text.split('\n').map(|l| l.strip_suffix('\r').unwrap_or(l)).collect();
     let count = lines.len();
     if start > count {
@@ -86,6 +93,15 @@ fn render_slice(text: &str, start: usize, max_lines: usize) -> IdeResult<String>
     if available <= max_lines {
         return Ok(range(start, count));
     }
+    if window {
+        let end = start + max_lines - 1;
+        return Ok(format!(
+            "{}\n\u{2026}{} more lines; read on with offset={}\u{2026}",
+            range(start, end),
+            count - end,
+            end + 1
+        ));
+    }
     let head = max_lines / 2;
     let tail = max_lines - head;
     let head_end = start + head - 1;
@@ -245,7 +261,7 @@ mod tests {
     use super::*;
 
     fn slice(text: &str, start: usize, max: usize) -> String {
-        render_slice(text, start, max).unwrap()
+        render_slice(text, start, max, false).unwrap()
     }
 
     #[test]
@@ -254,18 +270,27 @@ mod tests {
         assert_eq!(slice("a\r\nb\n", 1, 10), "L1: a\nL2: b\nL3: ");
         assert_eq!(slice("", 1, 10), "L1: ");
         assert_eq!(slice("a\nb\nc", 2, 10), "L2: b\nL3: c");
-        assert!(render_slice("", 2, 10).unwrap_err().message.contains("offset exceeds file length"));
-        assert!(render_slice("a\nb", 3, 10).unwrap_err().message.contains("offset exceeds file length"));
+        assert!(render_slice("", 2, 10, true).unwrap_err().message.contains("offset exceeds file length"));
+        assert!(render_slice("a\nb", 3, 10, true).unwrap_err().message.contains("offset exceeds file length"));
     }
 
     #[test]
-    fn keeps_head_and_tail_of_long_slices() {
+    fn keeps_head_and_tail_of_a_long_default_read() {
         let text = (1..=11).map(|n| format!("line {n}")).collect::<Vec<_>>().join("\n");
         assert_eq!(slice(&text, 1, 4), "L1: line 1\nL2: line 2\n…7 lines truncated…\nL10: line 10\nL11: line 11");
         assert_eq!(slice(&text, 3, 4), "L3: line 3\nL4: line 4\n…5 lines truncated…\nL10: line 10\nL11: line 11");
         assert_eq!(slice(&text, 1, 1), "…10 lines truncated…\nL11: line 11");
     }
 
+    #[test]
+    fn reads_an_explicit_range_exactly_and_says_where_to_read_on() {
+        let text = (1..=11).map(|n| format!("line {n}")).collect::<Vec<_>>().join("\n");
+        let window = |start, max| render_slice(&text, start, max, true).unwrap();
+        assert_eq!(window(5, 3), "L5: line 5\nL6: line 6\nL7: line 7\n…4 more lines; read on with offset=8…");
+        assert_eq!(window(1, 1), "L1: line 1\n…10 more lines; read on with offset=2…");
+        assert_eq!(window(10, 3), "L10: line 10\nL11: line 11", "the end of the file needs no marker");
+    }
+
     #[test]
     fn cuts_long_lines_at_utf16_units() {
         let long = "x".repeat(2100);

crates/ide-host/src/mcp/mod.rs

@@ -1,8 +1,9 @@
 //! Built-in IDE tools. Transport and discovery live in `ide-mcp`.
+mod check;
 mod edit;
 mod editors;
 mod requests;
-mod run;
+pub(crate) mod run;
 mod vcs;
 pub use requests::Requests;
 mod files;
@@ -16,6 +17,7 @@ use crate::Host;
 use ide_core::{CancellationToken, IdeError};
 use ide_mcp::{ToolCallError, ToolRegistry};
 pub use reports::{FileProblems, FocusedEditor, Reports};
+pub use run::agent::{AGENT_PARAM, AgentRun, AgentRuns, NAME_PREFIX, SHELL_PARAM};
 use std::path::{Path, PathBuf};
 use std::sync::Arc;
 
@@ -30,6 +32,7 @@ fn tools() -> Vec<tool::Tool> {
     let mut tools = files::tools();
     tools.extend(search::tools());
     tools.extend(editors::tools());
+    tools.push(check::check_files());
     tools.push(symbols::get_symbol_info());
     tools.push(symbols::find_references());
     tools.extend(edit::tools());

crates/ide-host/src/mcp/run/agent_tools.rs

@@ -0,0 +1,418 @@
+//! `run_command` and the tools that follow its tab up: `wait_for_run`, `read_run_output`,
+//! `get_run_status`, `send_run_input`, `stop_run` and `list_runs` (see [`super::agent`]).
+
+use super::agent::{AgentRun, INTERVENTION_ADVICE, TruncateMode, clean_output, tab_name, truncate_lines};
+use super::output::RUN_PREVIEW_MAX_LENGTH;
+use crate::mcp::run::timeout;
+use crate::mcp::tool::{Call, Output, Param, ParamType, Tool};
+use ide_core::{IdeError, IdeResult};
+use serde_json::{Map, Value};
+use std::sync::Arc;
+
+const RUN_TIMEOUT_MS: usize = 10_000;
+const WAIT_TIMEOUT_MS: usize = 30_000;
+const STOP_TIMEOUT_MS: usize = 10_000;
+/// Lines of output returned at most, by default (as JetBrains' `execute_terminal_command`).
+const DEFAULT_MAX_LINES: usize = 2000;
+/// Bytes of the log read for one result at most.
+const READ_CAP: usize = 1 << 20;
+/// Lines of output quoted when a name is still running.
+const BUSY_TAIL_LINES: usize = 20;
+
+const NAME: &str = "Tab name. OpenIDEA shows the tab as `_agent_<name>`; passing the prefixed name works too.";
+const SEQUENCE: &str = "\n\nUsing the same name for every command of one task reuses its tab: a name whose command \
+has finished starts the next command in the same tab. A name whose command is still running is refused (with that \
+command and its last output); stop it with `stop_run` first or use another name. Nothing is stopped implicitly.";
+const INTERVENTIONS: &str = "\n\nThe user sees every tab and can type into it, rerun or stop its command, or close \
+it. Results then carry `interventions` (for example `User input: …` or `The user reran this command at …`) and \
+`advice`: unless the user asked otherwise, stop what you are doing, tell the user you received the intervention and \
+wait for their confirmation before you continue.";
+const OUTPUT: &str = "\n\nThe command runs on pipes, not a terminal, so programs print plain lines (no progress \
+bars). `output` is that text cleaned of escape sequences, at most `maxLinesCount` lines (default 2000): beyond it, \
+`truncateMode` START (default) keeps the end, END the start, MIDDLE both ends, NONE everything, with a \
+`<<<...content truncated...>>>` line where lines were left out and `truncatedLines` saying how many. `outputStart` \
+and `nextOffset` are positions in the tab's raw output log; pass `nextOffset` as `offset` to read on.";
+const MAX_LINES: &str = "Lines of output to return at most (default 2000)";
+const TRUNCATE_MODE: &str = "Which lines to leave out beyond maxLinesCount: START (default, keeps the end), END \
+(keeps the start), MIDDLE (keeps both ends) or NONE";
+
+fn find(call: &Call) -> IdeResult<Arc<AgentRun>> {
+    let name = tab_name(&call.str("name")?)?;
+    call.host()
+        .mcp_agent_runs
+        .get(call.root(), &name)
+        .ok_or_else(|| IdeError::not_found(format!("no agent tab named `{name}` (see list_runs)")))
+}
+
+/// `status` of `run`, with interventions not told yet.
+fn result(run: &AgentRun, extra: Map<String, Value>) -> IdeResult<Output> {
+    let mut out = run.status();
+    out.extend(extra);
+    let interventions = run.take_interventions();
+    if !interventions.is_empty() {
+        out.insert("interventions".into(), interventions.into());
+        out.insert("advice".into(), INTERVENTION_ADVICE.into());
+    }
+    Output::json(Value::Object(out))
+}
+
+/// The output from `from` as the agent reads it: cleaned, then cut to `maxLinesCount` lines
+/// as `truncateMode` says.
+fn output_view(call: &Call, run: &AgentRun, from: u64) -> IdeResult<Map<String, Value>> {
+    let max_lines = match call.opt_i64("maxLinesCount")? {
+        Some(n) if n < 1 => return Err(IdeError::invalid("maxLinesCount must be > 0")),
+        Some(n) => n as usize,
+        None => DEFAULT_MAX_LINES,
+    };
+    let mode = match call.opt_str("truncateMode")? {
+        Some(name) => TruncateMode::parse(&name)
+            .ok_or_else(|| IdeError::invalid("truncateMode must be START, MIDDLE, END or NONE"))?,
+        None => TruncateMode::Start,
+    };
+    let len = run.log_len();
+    let from = from.min(len);
+    // A long output is read from the end that stays.
+    let start = if mode == TruncateMode::Start && len - from > READ_CAP as u64 { len - READ_CAP as u64 } else { from };
+    let (raw, start, end) = run.read(start, READ_CAP)?;
+    let (text, truncated) = truncate_lines(&clean_output(&raw), max_lines, mode);
+    let mut out = Map::new();
+    out.insert("output".into(), text.into());
+    if truncated > 0 {
+        out.insert("truncatedLines".into(), truncated.into());
+    }
+    out.insert("outputStart".into(), start.into());
+    out.insert("nextOffset".into(), end.into());
+    Ok(out)
+}
+
+fn deadline(call: &Call, default: usize) -> IdeResult<tokio::time::Instant> {
+    Ok(tokio::time::Instant::now() + timeout(call, default)?)
+}
+
+fn pattern(call: &Call) -> IdeResult<Option<regex_lite::Regex>> {
+    call.opt_str("pattern")?
+        .filter(|p| !p.is_empty())
+        .map(|p| regex_lite::Regex::new(&p).map_err(|e| IdeError::invalid(format!("invalid pattern: {e}"))))
+        .transpose()
+}
+
+fn offset(call: &Call, name: &str) -> IdeResult<Option<u64>> {
+    match call.opt_i64(name)? {
+        Some(n) if n < 0 => Err(IdeError::invalid(format!("{name} must not be negative"))),
+        n => Ok(n.map(|n| n as u64)),
+    }
+}
+
+fn busy(run: &AgentRun) -> IdeError {
+    let tail = run.tail(run.process_offset(), BUSY_TAIL_LINES, RUN_PREVIEW_MAX_LENGTH).map(|t| t.0).unwrap_or_default();
+    IdeError::invalid(format!(
+        "`{}` is still running `{}`. Stop it with stop_run first, or use another name.\nLast output:\n{}",
+        run.name,
+        run.command(),
+        clean_output(&tail).trim_end()
+    ))
+}
+
+pub fn run_command() -> Tool {
+    Tool::new(
+        "run_command",
+        &format!(
+            "Runs a shell command line in a new or reused tab of OpenIDEA's Run tool window, with the shell of \
+Settings › Tools › Terminal. The user is asked first (unless the IDE runs tools without \
+confirmation). Waits up to `timeout` milliseconds (default {RUN_TIMEOUT_MS}) for the command to finish; a command \
+still running then keeps running, and `wait_for_run`, `read_run_output`, `get_run_status`, `send_run_input` and \
+`stop_run` follow it up by name. Returns the tab's status (`state`: starting, running, stopping, succeeded, failed, \
+crashed, stoppedByAgent, stoppedByUser or startFailed; `exitCode`; `crash` with the signal or exception of a crashed \
+process) and its output so far.{OUTPUT}{SEQUENCE}{INTERVENTIONS}"
+        ),
+        |call| async move {
+            let name = tab_name(&call.str("name")?)?;
+            let command = call.str("command")?;
+            if command.trim().is_empty() {
+                return Err(IdeError::invalid("command must not be empty"));
+            }
+            let cwd = match call.opt_str("workingDirectory")?.filter(|d| !d.trim().is_empty()) {
+                Some(dir) => {
+                    let path = call.resolve_inside(&dir)?;
+                    if !path.is_dir() {
+                        return Err(IdeError::not_found(format!("workingDirectory {} is not a directory", dir)));
+                    }
+                    path
+                }
+                None => call.root().to_path_buf(),
+            };
+            let env = call.args.get("envs").filter(|v| !v.is_null()).map(|_| call.str_map("envs")).transpose()?;
+            let deadline = deadline(&call, RUN_TIMEOUT_MS)?;
+            let host = call.host();
+            let runs = &host.mcp_agent_runs;
+            if let Some(run) = runs.get(call.root(), &name).filter(|r| r.running()) {
+                return Err(busy(&run));
+            }
+            let shown_cwd = call.display(&cwd);
+            let mut detail = format!(
+                "{command}\n\nTab: {name}\nWorking directory: {}",
+                if shown_cwd.is_empty() { ".".to_owned() } else { shown_cwd.clone() }
+            );
+            for (key, value) in env.iter().flatten() {
+                detail.push_str(&format!("\n{key}={value}"));
+            }
+            call.confirm(&name, Some(detail)).await?;
+            let run = runs.prepare(call.root(), call.window(), &name, &command, &shown_cwd).map_err(|r| busy(&r))?;
+            let request = ide_core::event::McpUiRequest::AgentRun {
+                name: name.clone(),
+                command: command.clone(),
+                cwd: cwd.into(),
+                env: env.unwrap_or_default().into_iter().collect(),
+            };
+            if let Err(e) = call.ask(request).await {
+                let error = run.start_error();
+                runs.abandon(&run);
+                return Err(match error {
+                    Some(error) => IdeError::invalid(format!("`{name}` did not start: {error}")),
+                    None => e,
+                });
+            }
+            if let Some(error) = run.start_error() {
+                return Err(IdeError::invalid(format!("`{name}` did not start: {error}")));
+            }
+            let from = run.process_offset();
+            let end = run.wait(deadline, None, from, &call.cancel).await?;
+            let mut extra = output_view(&call, &run, from)?;
+            extra.insert("waitEnded".into(), end.as_str().into());
+            result(&run, extra)
+        },
+    )
+    .write()
+    .param(Param::required("name", ParamType::String, NAME))
+    .param(Param::required(
+        "command",
+        ParamType::String,
+        "Shell command line, e.g. `npm test -- --watch=false` or `cargo build && ./target/debug/app`",
+    ))
+    .param(Param::optional(
+        "workingDirectory",
+        ParamType::String,
+        "Directory inside the project to run in, relative to the project root; default: the project root",
+    ))
+    .param(Param::optional("envs", ParamType::StringMap, "Environment variables added for this command"))
+    .param(Param::optional(
+        "timeout",
+        ParamType::Integer,
+        "Milliseconds to wait for the command to finish before returning (0 returns once it started); the command \
+keeps running after it",
+    ))
+    .param(Param::optional("maxLinesCount", ParamType::Integer, MAX_LINES))
+    .param(Param::optional("truncateMode", ParamType::String, TRUNCATE_MODE))
+}
+
+pub fn wait_for_run() -> Tool {
+    Tool::new(
+        "wait_for_run",
+        &format!(
+            "Waits until the command of an agent tab finishes, its output matches `pattern`, the user intervenes, or \
+`timeout` milliseconds pass (default {WAIT_TIMEOUT_MS}). Cancelling the wait leaves the command running. Returns \
+`waitEnded` (exited, matched, userIntervened or timedOut), the tab's status and the output since `offset`. Use \
+`pattern` to wait for a server to be ready, e.g. `Listening on|Started .* in`.{OUTPUT}{INTERVENTIONS}"
+        ),
+        |call| async move {
+            let run = find(&call)?;
+            let deadline = deadline(&call, WAIT_TIMEOUT_MS)?;
+            let pattern = pattern(&call)?;
+            let from = offset(&call, "offset")?.unwrap_or_else(|| run.process_offset());
+            let end = run.wait(deadline, pattern.as_ref(), from, &call.cancel).await?;
+            let mut extra = output_view(&call, &run, from)?;
+            extra.insert("waitEnded".into(), end.as_str().into());
+            result(&run, extra)
+        },
+    )
+    .param(Param::required("name", ParamType::String, NAME))
+    .param(Param::optional("timeout", ParamType::Integer, "Milliseconds to wait at most"))
+    .param(Param::optional(
+        "pattern",
+        ParamType::String,
+        "Regular expression to wait for in the output after `offset` (as the command wrote it)",
+    ))
+    .param(Param::optional(
+        "offset",
+        ParamType::Integer,
+        "Where in the tab's output log to start: a `nextOffset` from an earlier result. Default: where the current \
+command's output starts",
+    ))
+    .param(Param::optional("maxLinesCount", ParamType::Integer, MAX_LINES))
+    .param(Param::optional("truncateMode", ParamType::String, TRUNCATE_MODE))
+}
+
+pub fn read_run_output() -> Tool {
+    Tool::new(
+        "read_run_output",
+        &format!(
+            "Reads the output log of an agent tab, which goes on across the commands and reruns of the tab: from \
+`offset` (a `nextOffset` from an earlier result), or from its start. Also returns the tab's status.\
+{OUTPUT}{INTERVENTIONS}"
+        ),
+        |call| async move {
+            let run = find(&call)?;
+            let from = offset(&call, "offset")?.unwrap_or(0);
+            let extra = output_view(&call, &run, from)?;
+            result(&run, extra)
+        },
+    )
+    .param(Param::required("name", ParamType::String, NAME))
+    .param(Param::optional("offset", ParamType::Integer, "Where in the log to read from"))
+    .param(Param::optional("maxLinesCount", ParamType::Integer, MAX_LINES))
+    .param(Param::optional("truncateMode", ParamType::String, TRUNCATE_MODE))
+}
+
+pub fn get_run_status() -> Tool {
+    Tool::new(
+        "get_run_status",
+        &format!(
+            "Returns the status of an agent tab: its command, `state` (starting, running, stopping, succeeded, \
+failed, crashed, stoppedByAgent, stoppedByUser or startFailed), `startedBy` (agent, or user when the user reran \
+it), times, `exitCode`, `crash`, `outputLength`, `lastOutputAt` (a running command silent for long may be waiting \
+for input) and `tabClosedAt` when the user closed the tab.{INTERVENTIONS}"
+        ),
+        |call| async move {
+            let run = find(&call)?;
+            result(&run, Map::new())
+        },
+    )
+    .param(Param::required("name", ParamType::String, NAME))
+}
+
+pub fn list_runs() -> Tool {
+    Tool::new(
+        "list_runs",
+        "Lists the agent tabs of the project (those started by `run_command`) with their status.",
+        |call| async move {
+            let runs: Vec<Value> =
+                call.host().mcp_agent_runs.list(call.root()).iter().map(|r| Value::Object(r.status())).collect();
+            Output::json(serde_json::json!({ "runs": runs }))
+        },
+    )
+}
+
+/// What a key does to a command on pipes.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+enum Key {
+    /// Writes this text to its input.
+    Text(&'static str),
+    /// Ctrl+C: stops it, as `stop_run` does.
+    Interrupt,
+    /// Ctrl+D: ends its input.
+    EndOfInput,
+}
+
+fn key(name: &str) -> IdeResult<Key> {
+    Ok(match name.trim().to_ascii_lowercase().replace(' ', "").as_str() {
+        "enter" | "return" => Key::Text("\n"),
+        "tab" => Key::Text("\t"),
+        "ctrl+c" => Key::Interrupt,
+        "ctrl+d" => Key::EndOfInput,
+        "escape" | "esc" | "backspace" | "ctrl+z" | "ctrl+\\" | "ctrl+l" | "up" | "down" | "left" | "right" => {
+            return Err(IdeError::invalid(format!(
+                "`{name}` is a terminal key, and the command runs on pipes, not a terminal: send text and Enter, \
+Ctrl+C to stop it or Ctrl+D to end its input"
+            )));
+        }
+        _ => return Err(IdeError::invalid(format!("unknown key `{name}`"))),
+    })
+}
+
+pub fn send_run_input() -> Tool {
+    Tool::new(
+        "send_run_input",
+        "Writes to the input of the running command of an agent tab, which runs on pipes: `text` as it is, then \
+`keys` in order: Enter (a line break), Tab, Ctrl+C (stops the command, as `stop_run` does) and Ctrl+D (ends its \
+input). Terminal keys (arrows, Escape, Backspace, Ctrl+Z…) are refused. To answer a prompt, pass the answer as \
+`text` and `keys: [\"Enter\"]`. The user sees the command's output in the tab. Returns the tab's status.",
+        |call| async move {
+            let run = find(&call)?;
+            let text = call.opt_str("text")?.unwrap_or_default();
+            let keys = call.str_list("keys")?.iter().map(|k| key(k)).collect::<IdeResult<Vec<_>>>()?;
+            if text.is_empty() && keys.is_empty() {
+                return Err(IdeError::invalid("pass `text`, `keys` or both"));
+            }
+            let id = run.live_process().ok_or_else(|| IdeError::invalid(format!("`{}` is not running", run.name)))?;
+            call.project().require_trust()?;
+            let host = call.host();
+            let mut data = text;
+            for key in keys {
+                match key {
+                    Key::Text(text) => data.push_str(text),
+                    Key::EndOfInput | Key::Interrupt => {
+                        if !data.is_empty() {
+                            host.processes.write_stdin(id, &std::mem::take(&mut data))?;
+                        }
+                        if key == Key::EndOfInput {
+                            crate::ops::run::close_stdin(&host, id)?;
+                        } else {
+                            run.agent_stopping();
+                            crate::ops::run::stop(&host, &run.window(), id)?;
+                            break;
+                        }
+                    }
+                }
+            }
+            if !data.is_empty() {
+                host.processes.write_stdin(id, &data)?;
+            }
+            result(&run, Map::new())
+        },
+    )
+    .write()
+    .param(Param::required("name", ParamType::String, NAME))
+    .param(Param::optional("text", ParamType::String, "Text to type"))
+    .param(Param::optional("keys", ParamType::StringList, "Keys to press after `text`"))
+}
+
+pub fn stop_run() -> Tool {
+    Tool::new(
+        "stop_run",
+        &format!(
+            "Stops the running command of an agent tab, the way the Run tool window's Stop does: it asks the \
+process tree to exit and, with `force`, kills it. Waits up to `timeout` milliseconds (default {STOP_TIMEOUT_MS}) \
+for it to end and returns the tab's status (`stoppedByAgent` once it ended). A process that ignores the request \
+keeps `stopping`: call again with `force`. The tab stays open with its output."
+        ),
+        |call| async move {
+            let run = find(&call)?;
+            let id = run.live_process().ok_or_else(|| IdeError::invalid(format!("`{}` is not running", run.name)))?;
+            let force = call.flag("force", false)?;
+            let deadline = deadline(&call, STOP_TIMEOUT_MS)?;
+            let host = call.host();
+            run.agent_stopping();
+            crate::ops::run::stop(&host, &run.window(), id)?;
+            if force {
+                // A second Stop kills the tree.
+                crate::ops::run::stop(&host, &run.window(), id)?;
+            }
+            let end = run.wait(deadline, None, run.log_len(), &call.cancel).await?;
+            let mut extra = Map::new();
+            extra.insert("waitEnded".into(), end.as_str().into());
+            result(&run, extra)
+        },
+    )
+    .write()
+    .param(Param::required("name", ParamType::String, NAME))
+    .param(Param::optional("force", ParamType::Boolean, "Kill the process tree instead of asking it to exit"))
+    .param(Param::optional("timeout", ParamType::Integer, "Milliseconds to wait for the command to end"))
+}
+
+pub fn tools() -> Vec<Tool> {
+    vec![run_command(), wait_for_run(), read_run_output(), get_run_status(), send_run_input(), stop_run(), list_runs()]
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn keys_are_what_pipes_can_take() {
+        assert_eq!(key(" enter ").unwrap(), Key::Text("\n"));
+        assert_eq!(key("Ctrl+C").unwrap(), Key::Interrupt);
+        assert_eq!(key("ctrl+d").unwrap(), Key::EndOfInput);
+        assert!(key("Up").unwrap_err().message.contains("runs on pipes"));
+        assert!(key("F13").unwrap_err().message.contains("unknown key"));
+    }
+}

crates/ide-host/src/mcp/run/build.rs

@@ -15,7 +15,6 @@ use std::sync::Arc;
 use std::time::Instant;
 
 const DEFAULT_TIMEOUT_MS: usize = 60_000;
-const MAX_TIMEOUT_MS: usize = 3_600_000;
 const MAX_PROBLEMS: usize = 300;
 /// Console lines attached to a failure whose messages were not parsed.
 const CONSOLE_LINES: usize = 200;
@@ -84,13 +83,13 @@ You have to use this tool after performing edits to validate if the edits are va
 In OpenIDEA the project's build system builds it (Maven, Gradle, Cargo, Go or TypeScript); with `filesToRebuild`, the \
 modules containing those files. Asks the user first for every call. Problems have the project-relative \
 `file` and 1-based `line` / `column`; at most 300 problems are listed, and `isSuccess` is false whenever one of them \
-is an ERROR. On timeout (at most 1 hour; 0 times out at once) the build is stopped.",
+is an ERROR. On timeout (0 times out at once) the build is stopped.",
         |call| async move {
             let files: Vec<String> =
                 call.str_list("filesToRebuild")?.into_iter().filter(|f| !f.trim().is_empty()).collect();
             let rebuild = call.flag("rebuild", false)? && files.is_empty();
             let kind = if rebuild { BuildKind::Rebuild } else { BuildKind::Build };
-            let limit = timeout(&call, DEFAULT_TIMEOUT_MS, MAX_TIMEOUT_MS)?;
+            let limit = timeout(&call, DEFAULT_TIMEOUT_MS)?;
             let mut targets: Vec<Option<PathBuf>> = Vec::new();
             let mut dirs: Vec<PathBuf> = Vec::new();
             for f in &files {

crates/ide-host/src/mcp/run/configs.rs

@@ -19,8 +19,6 @@ use std::sync::Arc;
 use std::time::{Duration, Instant};
 
 const DEFAULT_TIMEOUT_MS: usize = 10_000;
-/// No limit in JetBrains; the process keeps running after the timeout anyway.
-const MAX_TIMEOUT_MS: usize = 1_800_000;
 /// Output of a failed before-launch process kept for the error message.
 const MAX_PROCESS_OUTPUT_LENGTH: usize = 20_000;
 /// A before-launch build gets this long.
@@ -541,7 +539,7 @@ tool window; output files are private and deleted after a day.",
             )?;
             let wait = call.flag("waitForExit", true)?;
             // As JetBrains: `timeout` is ignored without waiting, and 0 returns without waiting.
-            let limit = if wait { Some(timeout(&call, DEFAULT_TIMEOUT_MS, MAX_TIMEOUT_MS)?) } else { None };
+            let limit = if wait { Some(timeout(&call, DEFAULT_TIMEOUT_MS)?) } else { None };
             let envs = call.args.get("envs").filter(|v| !v.is_null()).map(|_| call.str_map("envs")).transpose()?;
             let configs = load_configs(&call).await?;
             let mut config = match &target {

crates/ide-host/src/mcp/run/mod.rs

@@ -1,5 +1,7 @@
-//! Run configurations and builds; every call asks the user first.
+//! Run configurations, builds and agent commands; every start asks the user first.
 
+pub(crate) mod agent;
+mod agent_tools;
 mod build;
 mod configs;
 mod output;
@@ -11,15 +13,22 @@ use ide_core::IdeResult;
 use std::time::Duration;
 
 pub fn tools() -> Vec<Tool> {
-    vec![configs::get_run_configurations(), configs::execute_run_configuration(), build::build_project()]
+    let mut tools =
+        vec![configs::get_run_configurations(), configs::execute_run_configuration(), build::build_project()];
+    tools.extend(agent_tools::tools());
+    tools
 }
 
-/// The `timeout` argument: `default` when absent, at most `max` milliseconds. As in JetBrains
+/// Longest wait: far enough to be no limit, near enough not to overflow a deadline.
+const FOREVER_MS: u64 = 365 * 24 * 60 * 60 * 1000;
+
+/// The `timeout` argument in milliseconds, `default` when absent: the agent decides how long
+/// to wait (long waits are answered on an event stream, see `ide_mcp`). As in JetBrains
 /// (`withTimeoutOrNull`), zero or a negative value times out at once.
-fn timeout(call: &Call, default: usize, max: usize) -> IdeResult<Duration> {
+pub(crate) fn timeout(call: &Call, default: usize) -> IdeResult<Duration> {
     Ok(match call.opt_i64("timeout")? {
         None => Duration::from_millis(default as u64),
         Some(n) if n <= 0 => Duration::ZERO,
-        Some(n) => Duration::from_millis((n as u64).min(max as u64)),
+        Some(n) => Duration::from_millis((n as u64).min(FOREVER_MS)),
     })
 }

crates/ide-host/src/mcp/run/targets.rs

@@ -434,10 +434,23 @@ fn cwd_of(root: &Path, c: &RunConfig) -> String {
     cwd.trim_end_matches('/').to_owned()
 }
 
-/// Configs whose working directory most specifically contains `rel` (ties in their original order).
+/// The directory a config covers: a Cargo workspace member's own directory (its `cargo test -p`
+/// runs from the workspace root), else its working directory.
+fn scope_of(root: &Path, c: &RunConfig) -> String {
+    match c.extras.module.as_deref() {
+        Some(module) if c.kind == "cargo" => {
+            let module = module.replace('\\', "/");
+            let module = module.strip_prefix("./").unwrap_or(&module);
+            if module == "." { String::new() } else { module.trim_end_matches('/').to_owned() }
+        }
+        _ => cwd_of(root, c),
+    }
+}
+
+/// Configs whose scope ([`scope_of`]) most specifically contains `rel` (ties in their original order).
 fn all_closest<'a>(root: &Path, configs: &[&'a RunConfig], rel: &str) -> Vec<&'a RunConfig> {
     let score = |c: &RunConfig| -> Option<usize> {
-        let cwd = cwd_of(root, c);
+        let cwd = scope_of(root, c);
         if cwd.is_empty() { Some(0) } else { (rel == cwd || rel.starts_with(&format!("{cwd}/"))).then_some(cwd.len()) }
     };
     let scored: Vec<(&RunConfig, usize)> = configs.iter().filter_map(|c| score(c).map(|s| (*c, s))).collect();
@@ -922,6 +935,33 @@ mod tests {
         assert_eq!(c.args, ["test", "--", "math::tests::"]);
     }
 
+    #[test]
+    fn a_workspace_member_runs_its_own_tests() {
+        let root = Path::new("/p");
+        let member = |pkg: &str, dir: &str| {
+            let mut c = blank(
+                format!("cargo:test:{pkg}"),
+                "test",
+                "cargo",
+                "cargo".into(),
+                vec!["test".into(), "-p".into(), pkg.into()],
+            );
+            c.is_test = true;
+            c.extras.module = Some(dir.into());
+            c
+        };
+        let mut workspace = blank("cargo:test".into(), "test", "cargo", "cargo".into(), vec!["test".into()]);
+        workspace.is_test = true;
+        let configs = vec![member("ide-agent", "crates/ide-agent"), member("ide-mcp", "crates/ide-mcp"), workspace];
+        let src = "#[cfg(test)]\nmod tests {\n    #[test]\n    fn adds() {}\n}\n";
+        let rel = "crates/ide-mcp/src/stdio.rs";
+        let ts = detect(src, rel);
+        let c = target_config(root, &ts[1], rel, &configs, src).unwrap();
+        assert_eq!(c.args, ["test", "-p", "ide-mcp", "--", "stdio::tests::adds", "--exact"]);
+        let c = target_config(root, &ts[1], "src/lib.rs", &configs, src).unwrap();
+        assert!(!c.args.iter().any(|a| a == "-p"), "outside every member: the workspace's tests, {:?}", c.args);
+    }
+
     #[test]
     fn cargo_test_args_get_one_separator() {
         let root = Path::new("/p");

crates/ide-host/src/mcp/search.rs

@@ -38,6 +38,14 @@ const LINE_WINDOW: usize = 500;
 const PATHS_DESCRIPTION: &str = "Optional list of project-relative glob patterns to filter results. Supports '!' \
 excludes. Trailing '/' expands to '**'. Patterns without '/' are treated as '**/pattern'. Empty strings are ignored.";
 const LIMIT_DESCRIPTION: &str = "Maximum number of results to return";
+const CONTEXT_DESCRIPTION: &str = "Lines around each match to return besides the matched line (`lineText`): \"+N\" the \
+N lines after it (`contextAfter`), \"-N\" the N lines before it (`contextBefore`), \"N\" (or the number N) N lines on \
+each side. At most 50. Default: the matched line only.";
+/// A matched line longer than this (UTF-16 units) is cut to the match and [`SNIPPET_AROUND`] units
+/// on each side of it; a longer context line to its start.
+const MAX_LINE_TEXT: usize = 300;
+const SNIPPET_AROUND: usize = 100;
+const MAX_CONTEXT_LINES: u32 = 50;
 
 pub fn tools() -> Vec<Tool> {
     vec![search_text(), search_regex(), search_symbol(), search_file()]
@@ -49,6 +57,8 @@ fn search_text() -> Tool {
         "Searches for a text substring within project files.
 Use this tool for fast text search with match coordinates.
 Results include match coordinates when available (1-based line/column, end exclusive).
+Each result has the matched line (`lineText`; a long line cut to the match and 100 characters on each side, marked
+with …), and with `context` the lines around it.
 
 Paths are glob patterns relative to the project root.
 Examples: [\"src/**\", \"!**/test/**\"], [\"**/*.kt\"], [\"foo/\"].",
@@ -57,6 +67,7 @@ Examples: [\"src/**\", \"!**/test/**\"], [\"**/*.kt\"], [\"foo/\"].",
     .param(Param::required("q", ParamType::String, "Text to search for"))
     .param(Param::optional("paths", ParamType::StringList, PATHS_DESCRIPTION))
     .param(Param::optional("limit", ParamType::Integer, LIMIT_DESCRIPTION))
+    .param(Param::optional("context", ParamType::String, CONTEXT_DESCRIPTION))
     .output(result_schema())
 }
 
@@ -66,6 +77,8 @@ fn search_regex() -> Tool {
         "Searches for regex matches within project files.
 Use this tool when you need regex search with match coordinates.
 Results include match coordinates when available (1-based line/column, end exclusive).
+Each result has the matched line (`lineText`; a long line cut to the match and 100 characters on each side, marked
+with …), and with `context` the lines around it.
 The pattern uses Rust regex syntax and is case-sensitive; prefix `(?i)` to ignore case.
 
 Paths are glob patterns relative to the project root.
@@ -75,6 +88,7 @@ Examples: [\"src/**\", \"!**/test/**\"], [\"**/*.kt\"], [\"foo/\"].",
     .param(Param::required("q", ParamType::String, "Regex pattern to search for"))
     .param(Param::optional("paths", ParamType::StringList, PATHS_DESCRIPTION))
     .param(Param::optional("limit", ParamType::Integer, LIMIT_DESCRIPTION))
+    .param(Param::optional("context", ParamType::String, CONTEXT_DESCRIPTION))
     .output(result_schema())
 }
 
@@ -84,6 +98,7 @@ fn search_symbol() -> Tool {
         "Searches for symbols (classes, methods, fields).
 Use this tool for semantic lookup by identifier fragments.
 Results include match coordinates when available (1-based line/column, end exclusive).
+Project results have their line (`lineText`), and with `context` the lines around it.
 
 Paths are glob patterns relative to the project root.
 By default this searches project symbols only.
@@ -99,6 +114,7 @@ If you don't find a suitable result, try again with include_external=true to sea
 with include_external=true.",
     ))
     .param(Param::optional("limit", ParamType::Integer, LIMIT_DESCRIPTION))
+    .param(Param::optional("context", ParamType::String, CONTEXT_DESCRIPTION))
     .output(result_schema())
 }
 
@@ -145,6 +161,13 @@ struct SearchItem {
     name: Option<String>,
     #[serde(skip_serializing_if = "Option::is_none")]
     container: Option<String>,
+    /// The text of `start_line` (cut when long).
+    #[serde(skip_serializing_if = "Option::is_none")]
+    line_text: Option<String>,
+    #[serde(skip_serializing_if = "Vec::is_empty")]
+    context_before: Vec<String>,
+    #[serde(skip_serializing_if = "Vec::is_empty")]
+    context_after: Vec<String>,
 }
 
 impl SearchItem {
@@ -182,7 +205,9 @@ fn result_schema() -> Value {
                 "type": "object",
                 "properties": {
                     "filePath": string, "startLine": int, "startColumn": int, "endLine": int, "endColumn": int,
-                    "name": string, "container": string,
+                    "name": string, "container": string, "lineText": string,
+                    "contextBefore": { "type": "array", "items": string },
+                    "contextAfter": { "type": "array", "items": string },
                 },
                 "required": ["filePath"],
             } },
@@ -207,6 +232,87 @@ fn query(call: &Call, empty: &str) -> IdeResult<String> {
     Ok(q)
 }
 
+// --- matched lines -------------------------------------------------------------
+
+/// The `context` argument as (lines before, lines after).
+fn context(call: &Call) -> IdeResult<(u32, u32)> {
+    let invalid = || IdeError::invalid("context must be \"+N\", \"-N\" or N (lines after, before, or on each side)");
+    let (sign, n) = match call.args.get("context") {
+        None | Some(Value::Null) => return Ok((0, 0)),
+        Some(Value::Number(n)) => (None, n.as_u64().ok_or_else(invalid)?),
+        Some(Value::String(s)) => {
+            let s = s.trim();
+            match s.strip_prefix('+').map(|r| ('+', r)).or_else(|| s.strip_prefix('-').map(|r| ('-', r))) {
+                Some((sign, rest)) => (Some(sign), rest.trim().parse().map_err(|_| invalid())?),
+                None => (None, s.parse().map_err(|_| invalid())?),
+            }
+        }
+        Some(_) => return Err(invalid()),
+    };
+    let n = (n.min(MAX_CONTEXT_LINES as u64)) as u32;
+    Ok(match sign {
+        Some('+') => (0, n),
+        Some(_) => (n, 0),
+        None => (n, n),
+    })
+}
+
+/// `line`, or when longer than [`MAX_LINE_TEXT`] UTF-16 units, the part from [`SNIPPET_AROUND`]
+/// units before 0-based UTF-16 column `start` to as many after `end`, with `…` where it was cut.
+fn snippet(line: &str, start: usize, end: usize) -> String {
+    let units: usize = line.chars().map(char::len_utf16).sum();
+    if units <= MAX_LINE_TEXT {
+        return line.to_owned();
+    }
+    let from = start.saturating_sub(SNIPPET_AROUND);
+    let to = end.max(start).saturating_add(SNIPPET_AROUND).min(units);
+    let (mut out, mut at) = (String::new(), 0);
+    for c in line.chars() {
+        if at >= from && at < to {
+            out.push(c);
+        }
+        at += c.len_utf16();
+    }
+    let before = if from > 0 { "\u{2026}" } else { "" };
+    let after = if to < units { "\u{2026}" } else { "" };
+    format!("{before}{out}{after}")
+}
+
+/// A context line: its first [`MAX_LINE_TEXT`] UTF-16 units.
+fn context_line(line: &str) -> String {
+    snippet(line, 0, MAX_LINE_TEXT.saturating_sub(SNIPPET_AROUND))
+}
+
+/// Fills `line_text` and the context of `items`, whose files are `absolute(item)` (none: left
+/// as they are); each file is read once, with unsaved editor text.
+async fn fill_lines(
+    call: &Call,
+    items: &mut [SearchItem],
+    absolute: impl Fn(&SearchItem) -> Option<PathBuf>,
+    (before, after): (u32, u32),
+) {
+    let host = call.host();
+    let mut current: Option<(PathBuf, Option<Vec<String>>)> = None;
+    for item in items {
+        let (Some(path), Some(line)) = (absolute(item), item.start_line) else { continue };
+        if current.as_ref().is_none_or(|(p, _)| p != &path) {
+            let text = crate::ops::fs::read_text(&host, call.window(), path.clone()).await.ok();
+            let lines = text.map(|t| t.split('\n').map(|l| l.strip_suffix('\r').unwrap_or(l).to_owned()).collect());
+            current = Some((path, lines));
+        }
+        let Some((_, Some(lines))) = &current else { continue };
+        let index = line as usize - 1;
+        let Some(text) = lines.get(index) else { continue };
+        let start = item.start_column.unwrap_or(1) as usize - 1;
+        let end = if item.end_line == Some(line) { item.end_column.map_or(start, |c| c as usize - 1) } else { start };
+        item.line_text = Some(snippet(text, start, end));
+        let first = index.saturating_sub(before as usize);
+        item.context_before = lines[first..index].iter().map(|l| context_line(l)).collect();
+        let last = (index + after as usize).min(lines.len() - 1);
+        item.context_after = lines[index + 1..=last].iter().map(|l| context_line(l)).collect();
+    }
+}
+
 // --- path globs ----------------------------------------------------------------
 
 /// The `paths` argument: project-relative globs, `!` excludes.
@@ -416,6 +522,7 @@ struct TextHit {
 async fn text_search(call: Call, is_regex: bool) -> IdeResult<Output> {
     let pattern = query(&call, if is_regex { "Regex pattern is empty" } else { "Search text is empty" })?;
     let limit = limit(&call, DEFAULT_LIMIT)?;
+    let around = context(&call)?;
     let scope = PathScope::new(call.root(), &call.str_list("paths")?)?;
     // Globs Find in Files cannot take are applied afterwards, so the engine must not
     // stop at `limit` matches the filter may drop.
@@ -494,7 +601,7 @@ async fn text_search(call: Call, is_regex: bool) -> IdeResult<Output> {
     let more = hits.len() > limit || summary.limit_hit || timed_out;
     hits.truncate(limit);
     extend_spanning(&call, &query, &mut hits, spanning).await;
-    let items = hits
+    let mut items: Vec<SearchItem> = hits
         .into_iter()
         .map(|h| SearchItem {
             file_path: h.file_path,
@@ -505,6 +612,9 @@ async fn text_search(call: Call, is_regex: bool) -> IdeResult<Output> {
             ..Default::default()
         })
         .collect();
+    let absolute: std::collections::HashMap<&str, &Path> =
+        files.iter().map(|(path, file)| (path.as_str(), file.path.0.as_path())).collect();
+    fill_lines(&call, &mut items, |item| absolute.get(item.file_path.as_str()).map(|p| p.to_path_buf()), around).await;
     let partial_result_reason = timed_out.then_some(SEARCH_TIMEOUT_PARTIAL_RESULT_REASON);
     Output::json(SearchResult { items, more, partial_result_reason })
 }
@@ -726,6 +836,7 @@ async fn symbol_search(call: Call) -> IdeResult<Output> {
     let started = Instant::now();
     let q = query(&call, "Search query is empty")?;
     let limit = limit(&call, SYMBOL_SEARCH_DEFAULT_LIMIT)?;
+    let around = context(&call)?;
     let scope = PathScope::new(call.root(), &call.str_list("paths")?)?;
     let external = call.flag("include_external", false)?;
     let host = call.host();
@@ -775,6 +886,13 @@ async fn symbol_search(call: Call) -> IdeResult<Output> {
     }
     let more = items.len() > limit || timed_out;
     items.truncate(limit);
+    // Project files (relative paths, or absolute ones of content roots); library URIs are left out.
+    let root = call.root().to_path_buf();
+    let absolute = |item: &SearchItem| {
+        let path = Path::new(&item.file_path);
+        (!item.file_path.contains("://")).then(|| if path.is_absolute() { path.to_path_buf() } else { root.join(path) })
+    };
+    fill_lines(&call, &mut items, absolute, around).await;
     let indexing = indexing_before || project.index.status().indexing;
     let partial_result_reason = if indexing {
         Some(INDEXING_PARTIAL_RESULT_REASON)
@@ -869,6 +987,17 @@ mod tests {
         assert_eq!(byte_at("ab", 5), None);
     }
 
+    #[test]
+    fn long_lines_are_cut_around_the_match() {
+        assert_eq!(snippet("short line", 0, 5), "short line");
+        let line = format!("{}needle{}", "a".repeat(400), "b".repeat(400));
+        let cut = snippet(&line, 400, 406);
+        assert_eq!(cut, format!("\u{2026}{}needle{}\u{2026}", "a".repeat(100), "b".repeat(100)));
+        let start = snippet(&line, 0, 0);
+        assert!(start.starts_with('a') && start.ends_with('\u{2026}') && start.chars().count() == 101);
+        assert_eq!(context_line(&"x".repeat(1000)).chars().count(), MAX_LINE_TEXT + 1);
+    }
+
     #[test]
     fn path_scopes() {
         let (_dir, root) = root();

crates/ide-host/src/ops/build.rs

@@ -313,10 +313,11 @@ pub async fn build_sync(
     if tool == BuildTool::Gradle {
         // The sync may report project folders outside the project (`includeFlat`): index and list them.
         project.refresh_index_scope();
-        project.sink.emit(ide_core::IdeEvent::ProjectRootsChanged { root: project.root.clone().into() });
         let p = project.clone();
         tokio::task::spawn_blocking(move || p.refresh_repositories());
     }
+    // New source folders and dependency versions: the Project view and External Libraries reload.
+    project.sink.emit(ide_core::IdeEvent::ProjectRootsChanged { root: project.root.clone().into() });
     if tool == BuildTool::Maven
         && model.maven.is_some()
         && let Some(bridge) = &project.kotlin_bridge
@@ -455,7 +456,8 @@ pub async fn maven_dependency_declaration(
 /// absolute for a parent POM opened from the local repository): the definition of the
 /// `${property}` at the caret, or the `<dependencyManagement>` / `<pluginManagement>`
 /// entry providing the dependency's / plugin's version, along the parent chain (into
-/// the local repository when a parent is not in the project). `None` when nothing
+/// the local repository when a parent is not in the project), else the artifact's own
+/// POM (a project module's, or the local repository's). `None` when nothing
 /// resolvable is under the caret.
 pub async fn maven_goto_declaration(host: &Host, window: &str, pom: String, pos: Pos) -> IdeResult<Option<PomGoto>> {
     let project = host.project(window)?;
@@ -466,7 +468,19 @@ pub async fn maven_goto_declaration(host: &Host, window: &str, pom: String, pos:
         let settings = project.settings.effective();
         let repo = ide_sdk::apply::maven_local_repository(&project.root, &settings)
             .or_else(ide_build::maven::default_local_repo);
-        Ok(ide_build::maven::goto_declaration(&text, &path, pos, repo))
+        let modules = || {
+            let model = load(&project.root, &project.build_cache_dir(), &settings).maven.unwrap_or_default();
+            model
+                .projects
+                .into_iter()
+                .map(|p| ide_build::maven::ModulePom {
+                    group_id: p.group_id,
+                    artifact_id: p.artifact_id,
+                    pom: project.root.join(&p.pom),
+                })
+                .collect()
+        };
+        Ok(ide_build::maven::goto_declaration_in(&text, &path, pos, repo, modules))
     })
     .await
     .map_err(join_err)?

crates/ide-host/src/ops/run.rs

@@ -234,7 +234,19 @@ pub async fn start_request(
 ) -> IdeResult<RunInfo> {
     let cancel = request.map(|id| host.begin_request(id)).unwrap_or_default();
     let operation = config.extras.params.get("plugin.operation").cloned();
-    let result = start_inner(host, window, config, on_output, &cancel).await;
+    let mut config = config;
+    let agent = match host.project(window) {
+        Ok(project) => host.mcp_agent_runs.launch(&project.root, window, &mut config),
+        Err(_) => None,
+    };
+    let on_output = match &agent {
+        Some(agent) => agent.wrap_output(on_output),
+        None => on_output,
+    };
+    let result = start_inner(host, window, config, on_output, agent.as_ref(), &cancel).await;
+    if let Some(agent) = &agent {
+        agent.started(&result);
+    }
     if let Some(id) = request {
         host.end_request(id);
     }
@@ -249,6 +261,7 @@ async fn start_inner(
     window: &str,
     mut config: RunConfig,
     on_output: Emit<OutputChunk>,
+    agent: Option<&crate::mcp::run::agent::Launch>,
     cancel: &ide_core::CancellationToken,
 ) -> IdeResult<RunInfo> {
     if cancel.is_cancelled() {
@@ -282,6 +295,9 @@ async fn start_inner(
     if let Some(plugins) = host.plugin_host() {
         sink = plugins.run_operation_sink(window, &mut config, sink)?;
     }
+    if let Some(agent) = agent {
+        sink = agent.wrap_sink(sink);
+    }
     if config.command.is_empty() {
         return Err(IdeError::invalid("run configuration has no command"));
     }
@@ -450,6 +466,7 @@ pub fn stop(host: &Host, window: &str, id: RunId) -> IdeResult<()> {
     if let Some(plugins) = host.plugin_host() {
         plugins.run_operation_stopped(id);
     }
+    host.mcp_agent_runs.stopping(id);
     let settings = match host.project(window) {
         Ok(p) => p.settings.effective(),
         Err(_) => host.global_settings.effective(),
@@ -461,7 +478,9 @@ pub fn stop(host: &Host, window: &str, id: RunId) -> IdeResult<()> {
     host.processes.stop_with_grace(id, grace)
 }
 
+/// Input the user typed into a run (the agent's goes to the process directly).
 pub fn stdin(host: &Host, id: RunId, data: &str) -> IdeResult<()> {
+    host.mcp_agent_runs.user_input(id, data);
     if host.remote.runs.contains(id) {
         return host.remote.runs.write_stdin(id, data);
     }

crates/ide-host/src/plugins/api.rs

@@ -1531,6 +1531,19 @@ impl HostApi for PluginApi {
         }
         Ok(())
     }
+    fn open_diff(
+        &self,
+        client: &str,
+        diff: ide_plugin::ContentDiff,
+        file_name: Option<String>,
+    ) -> Result<(), HostError> {
+        super::execution::validate_diff(&diff)?;
+        if let Some(name) = &file_name {
+            super::execution::label(name, 256)?;
+        }
+        self.shared.sink.emit(Some(client), PluginEvent::OpenDiff { plugin_id: self.id().into(), diff, file_name });
+        Ok(())
+    }
     fn reply_content_tab(
         &self,
         client: &str,

crates/ide-host/src/plugins/execution.rs

@@ -72,14 +72,19 @@ pub(super) fn validate_reply(reply: &ContentTabReply) -> Result<(), HostError> {
         return Err(HostError::Invalid("content status or error too long".into()));
     }
     if let Some(diff) = &reply.diff {
-        body(&diff.left)?;
-        body(&diff.right)?;
-        for value in [&diff.left_label, &diff.right_label].into_iter().flatten() {
-            label(value, 128)?;
-        }
-        if let Some(title) = &diff.title {
-            label(title, 256)?;
-        }
+        validate_diff(diff)?;
+    }
+    Ok(())
+}
+
+pub(super) fn validate_diff(diff: &ide_plugin::ContentDiff) -> Result<(), HostError> {
+    body(&diff.left)?;
+    body(&diff.right)?;
+    for value in [&diff.left_label, &diff.right_label].into_iter().flatten() {
+        label(value, 128)?;
+    }
+    if let Some(title) = &diff.title {
+        label(title, 256)?;
     }
     Ok(())
 }

crates/ide-host/src/plugins/remote_host.rs

@@ -188,6 +188,7 @@ pub fn forwarded(event: &PluginEvent) -> bool {
         PluginEvent::RunTargetsChanged
             | PluginEvent::WindowRequest { .. }
             | PluginEvent::ContentTabReply { .. }
+            | PluginEvent::OpenDiff { .. }
             | PluginEvent::DecorationsChanged { .. }
             | PluginEvent::EditorOpen { .. }
             | PluginEvent::EditorRanges { .. }

crates/ide-host/src/plugins/types.rs

@@ -218,6 +218,9 @@ pub enum PluginEvent {
     /// Reply to a content action in this window.
     #[serde(rename_all = "camelCase")]
     ContentTabReply { plugin_id: String, request_id: String, reply: ide_plugin::ContentTabReply },
+    /// Open two texts in this window's diff viewer.
+    #[serde(rename_all = "camelCase")]
+    OpenDiff { plugin_id: String, diff: ide_plugin::ContentDiff, file_name: Option<String> },
 
     /// Plugins, their status or their contributions changed: re-fetch `plugin_list`.
     CommandsChanged,

crates/ide-host/tests/mcp.rs

@@ -112,6 +112,16 @@ async fn reads_unsaved_text_and_searches_the_overlay_with_a_limit() {
     assert_eq!(found["more"], true);
     let all = h.json("search_text", json!({"q":"fresh","limit":20})).await;
     assert_eq!(all["items"][0]["filePath"], "src/a.txt");
+    // The matched line comes with the result (unsaved text included), and lines around it on request.
+    assert_eq!(all["items"][0]["lineText"], "fresh needle text");
+    assert!(all["items"][0].get("contextAfter").is_none());
+    let after = h.json("search_text", json!({"q":"fresh","context":"+1"})).await;
+    assert_eq!(after["items"][0]["contextAfter"], json!(["needle needle"]));
+    let before = h.json("search_regex", json!({"q":"needle needle","context":"-1"})).await;
+    assert_eq!(before["items"][0]["lineText"], "needle needle");
+    assert_eq!(before["items"][0]["contextBefore"], json!(["fresh needle text"]));
+    let bad = h.error("search_text", json!({"q":"fresh","context":"around"})).await;
+    assert!(bad.contains("context must be"), "{bad}");
     let all = h.json("search_text", json!({"q":"needle","limit":20})).await;
     assert!(all["items"].as_array().unwrap().iter().all(|v| !v["filePath"].as_str().unwrap().contains("ignored")));
     let files = h.json("search_file", json!({"q":"*.txt","paths":["src/**"]})).await;
@@ -453,3 +463,166 @@ async fn brave_mode_runs_tools_without_asking_only_from_the_global_settings() {
     assert!(!format!("{result:?}").contains("denied"), "{result:?}");
     assert!(!h.events.lock().unwrap().iter().any(|e| matches!(e, IdeEvent::McpRequest { .. })), "nothing asked");
 }
+
+#[tokio::test(flavor = "multi_thread")]
+async fn check_files_says_why_a_file_could_not_be_checked() {
+    let h = Harness::new();
+    let untrusted = h.json("check_files", json!({"filePaths": ["src/a.txt"]})).await;
+    assert_eq!(untrusted["files"][0]["status"], "untrusted", "{untrusted}");
+    h.trust().await;
+    let files = h.json("check_files", json!({"filePaths": ["src/a.txt", "src/gone.txt"], "timeout": 5000})).await;
+    assert_eq!(files["files"][0]["filePath"], "src/a.txt");
+    assert_eq!(files["files"][0]["status"], "noLanguageServer", "{files}");
+    assert_eq!(files["files"][0]["problems"], json!([]));
+    assert_eq!(files["files"][1]["status"], "failed", "{files}");
+    assert!(files["files"][1]["error"].is_string());
+    // No cap of the tool's own: a very long timeout is taken as given, without overflowing.
+    let long = h.json("check_files", json!({"filePaths": ["src/a.txt"], "timeout": 9_000_000_000_000_i64})).await;
+    assert_eq!(long["files"][0]["status"], "noLanguageServer", "{long}");
+    let none = h.error("check_files", json!({"filePaths": []})).await;
+    assert!(none.contains("at least one file"), "{none}");
+}
+
+/// Answers `run_command`'s window requests the way the Run tool window does: starts the
+/// agent tab's configuration (shell from the default) and says whether it started. Returns
+/// the configurations it started, for reruns.
+#[cfg(unix)]
+fn run_tool_window(h: &Harness) -> Arc<std::sync::Mutex<Vec<ide_run::RunConfig>>> {
+    let started = Arc::new(std::sync::Mutex::new(Vec::new()));
+    let (host, events, out) = (h.host.clone(), h.events.clone(), started.clone());
+    tokio::spawn(async move {
+        let mut handled = std::collections::HashSet::new();
+        loop {
+            let request = events.lock().unwrap().iter().find_map(|e| match e {
+                IdeEvent::McpRequest {
+                    id,
+                    request: ide_core::event::McpUiRequest::AgentRun { name, command, cwd, env },
+                } if !handled.contains(id) => Some((*id, name.clone(), command.clone(), cwd.clone(), env.clone())),
+                _ => None,
+            });
+            let Some((id, name, command, cwd, env)) = request else {
+                tokio::time::sleep(std::time::Duration::from_millis(10)).await;
+                continue;
+            };
+            handled.insert(id);
+            let mut config = ide_run::RunConfig {
+                id: format!("mcp-agent:{name}"),
+                name: name.clone(),
+                kind: "shell".into(),
+                command,
+                args: Vec::new(),
+                cwd: Some(cwd),
+                env,
+                detected: false,
+                is_test: false,
+                debug_adapter: None,
+                allow_parallel: true,
+                extras: Default::default(),
+            };
+            config.extras.params.insert(ide_host::mcp::AGENT_PARAM.into(), name);
+            config.extras.target = Some(String::new());
+            out.lock().unwrap().push(config.clone());
+            let result = ide_host::ops::run::start(&host, "main", config, Arc::new(|_| {})).await;
+            let error = result.err().map(|e| e.message);
+            let _ = host.mcp_requests.answer("main", id, error.is_none(), error);
+        }
+    });
+    started
+}
+
+#[cfg(unix)]
+fn agent_process(h: &Harness, name: &str) -> ide_core::RunId {
+    let id = format!("mcp-agent:{name}");
+    h.host.processes.list().into_iter().filter(|r| r.config_id == id && r.running).map(|r| r.id).max().unwrap()
+}
+
+#[cfg(unix)]
+#[tokio::test(flavor = "multi_thread")]
+async fn agent_commands_run_in_named_tabs_and_report_what_the_user_did() {
+    let h = Harness::new();
+    h.trust().await;
+    h.host.mcp_requests.set_ready("main", true);
+    h.host
+        .global_settings
+        .set(ide_workspace::SettingsScope::Global, "mcpServer.runWithoutConfirmation", json!(true))
+        .unwrap();
+    let started = run_tool_window(&h);
+
+    // A command that finishes within the wait, in a tab named with the prefix.
+    let done = h.json("run_command", json!({"name": "check", "command": "echo hel''lo; exit 3"})).await;
+    assert_eq!(done["name"], "_agent_check", "{done}");
+    assert_eq!(done["state"], "failed", "{done}");
+    assert_eq!(done["exitCode"], 3);
+    assert_eq!(done["startedBy"], "agent");
+    assert!(done["output"].as_str().unwrap().contains("hello"), "{done}");
+    assert!(done.get("interventions").is_none());
+
+    // The finished name runs the next command; a running one is refused, never stopped.
+    let running =
+        h.json("run_command", json!({"name": "_agent_check", "command": "echo ready; sleep 30", "timeout": 0})).await;
+    assert_eq!(running["state"], "running", "{running}");
+    let matched = h.json("wait_for_run", json!({"name": "check", "pattern": "(?m)^ready", "timeout": 10000})).await;
+    assert_eq!(matched["waitEnded"], "matched", "{matched}");
+    let refused = h.error("run_command", json!({"name": "check", "command": "true"})).await;
+    assert!(refused.contains("still running `echo ready; sleep 30`"), "{refused}");
+    assert!(refused.contains("Last output:\nready"), "the refusal quotes the last output: {refused}");
+
+    // What the user types (a line from the Run console's input) ends a wait at once, with advice for the agent.
+    let process = agent_process(&h, "_agent_check");
+    ide_host::ops::run::stdin(&h.host, process, "yes\n").unwrap();
+    let typed = h.json("wait_for_run", json!({"name": "check", "timeout": 10000})).await;
+    assert_eq!(typed["waitEnded"], "userIntervened", "{typed}");
+    assert_eq!(typed["interventions"][0]["message"], "User input: yes");
+    assert!(typed["advice"].as_str().unwrap().contains("Do not stop the process"));
+    let input = h.json("send_run_input", json!({"name": "check", "text": "abc", "keys": ["Enter"]})).await;
+    assert!(input.get("interventions").is_none(), "the agent's own input is no intervention: {input}");
+
+    let stopped = h.json("stop_run", json!({"name": "check", "force": true, "timeout": 10000})).await;
+    assert_eq!(stopped["state"], "stoppedByAgent", "{stopped}");
+    assert!(stopped.get("interventions").is_none());
+
+    // The user's Stop, rerun and closing the tab are reported with their time.
+    h.json("run_command", json!({"name": "server", "command": "sleep 30", "timeout": 0})).await;
+    ide_host::ops::run::stop(&h.host, "main", agent_process(&h, "_agent_server")).unwrap();
+    let stop = h.json("wait_for_run", json!({"name": "server", "timeout": 10000})).await;
+    assert!(stop["interventions"][0]["message"].as_str().unwrap().starts_with("The user stopped this command at"));
+    let ended = h.json("wait_for_run", json!({"name": "server", "timeout": 10000})).await;
+    assert_eq!(ended["state"], "stoppedByUser", "{ended}");
+
+    let config = started.lock().unwrap().last().cloned().unwrap();
+    ide_host::ops::run::start(&h.host, "main", config, Arc::new(|_| {})).await.unwrap();
+    let status = h.json("get_run_status", json!({"name": "server"})).await;
+    assert_eq!(status["startedBy"], "user", "{status}");
+    assert!(status["interventions"][0]["message"].as_str().unwrap().starts_with("The user reran this command at"));
+    h.json("stop_run", json!({"name": "server", "force": true, "timeout": 10000})).await;
+    h.host.mcp_agent_runs.closed(&h.root, "_agent_server");
+    let closed = h.json("get_run_status", json!({"name": "server"})).await;
+    assert!(closed["tabClosedAt"].is_string(), "{closed}");
+    assert!(closed["interventions"][0]["message"].as_str().unwrap().starts_with("The user closed this tab at"));
+
+    let log = h.json("read_run_output", json!({"name": "check", "maxLinesCount": 20})).await;
+    assert!(log["output"].as_str().unwrap().contains("ready"), "{log}");
+    let from_start = h.json("read_run_output", json!({"name": "check", "offset": 0})).await;
+    assert!(from_start["output"].as_str().unwrap().contains("hello"), "one log across the tab's commands");
+    let runs = h.json("list_runs", json!({})).await;
+    assert_eq!(runs["runs"].as_array().unwrap().len(), 2, "{runs}");
+    let missing = h.error("get_run_status", json!({"name": "nothing"})).await;
+    assert!(missing.contains("no agent tab named `_agent_nothing`"), "{missing}");
+
+    // Pipes: plain lines, cleaned of escapes and cut to maxLinesCount (the end stays by default).
+    let printf = "printf '\\033[31mone\\033[0m\\ntwo\\nthree\\n'";
+    let lines =
+        h.json("run_command", json!({"name": "lines", "command": printf, "maxLinesCount": 2, "timeout": 10000})).await;
+    assert_eq!(lines["output"], "<<<...content truncated...>>>\ntwo\nthree\n", "{lines}");
+    assert_eq!(lines["truncatedLines"], 1);
+    let head = h.json("read_run_output", json!({"name": "lines", "maxLinesCount": 1, "truncateMode": "END"})).await;
+    assert_eq!(head["output"], "one\n<<<...content truncated...>>>\n", "{head}");
+
+    // Ctrl+C stops the command as stop_run does; terminal keys have no meaning on pipes.
+    h.json("run_command", json!({"name": "interrupt", "command": "sleep 30", "timeout": 0})).await;
+    let key = h.error("send_run_input", json!({"name": "interrupt", "keys": ["Up"]})).await;
+    assert!(key.contains("runs on pipes"), "{key}");
+    h.json("send_run_input", json!({"name": "interrupt", "keys": ["Ctrl+C"]})).await;
+    let interrupted = h.json("wait_for_run", json!({"name": "interrupt", "timeout": 10000})).await;
+    assert_eq!(interrupted["state"], "stoppedByAgent", "{interrupted}");
+}

crates/ide-host/tests/plugins.rs

@@ -6352,6 +6352,26 @@ fn api14_stage3_configurations_test_results_and_content_actions_use_real_exports
     assert!(f.host.parse_test_results("main", "plugin:execution:dynamic", "trap".into()).unwrap().is_none());
 }
 
+#[cfg(unix)]
+#[test]
+fn a_plugin_command_opens_a_diff_in_its_window() {
+    let f = execution_fixture();
+    f.take_events();
+    f.run("execution", "diff", None).unwrap();
+    f.host.flush_events_at(Instant::now() + Duration::from_secs(3));
+    assert!(eventually(|| {
+        f.events.lock().iter().any(|(client, event)| {
+            client.as_deref() == Some("main")
+                && matches!(event, PluginEvent::OpenDiff { plugin_id, diff, file_name }
+                    if plugin_id == "execution"
+                        && diff.left == "before\n"
+                        && diff.right == "after\n"
+                        && diff.title.as_deref() == Some("Review")
+                        && file_name.as_deref() == Some("src/review.rs"))
+        })
+    }));
+}
+
 #[test]
 fn api14_fixture_exports_test_selection() {
     let f = fixture(Limits::default());

crates/ide-lsp/src/inspect.rs

@@ -22,6 +22,9 @@ use std::time::{Duration, Instant};
 /// How long Inspect Code waits for a server that is still starting (jdtls,
 /// rust-analyzer on a large workspace).
 const INSPECT_START_WAIT: Duration = Duration::from_secs(60);
+/// Quiet period after a publish before a checked file counts as done (follow-up publishes:
+/// syntax first, semantics later).
+const CHECK_SETTLE: Duration = Duration::from_millis(500);
 
 #[derive(Clone, Copy, Debug)]
 pub struct InspectOptions {
@@ -48,6 +51,29 @@ pub trait InspectHost: Send + Sync + 'static {
     fn close(&self, doc: DocId);
 }
 
+/// One language server's part in a [`DocumentCheck`].
+#[derive(Clone, Debug)]
+pub struct CheckedServer {
+    pub name: String,
+    /// Its state when the check ended: not `Ready`/`Busy` means it could not check.
+    pub status: ide_core::event::ServerStatus,
+    /// Why it isn't running (not installed, misconfigured, crashed), as the status bar says.
+    pub message: Option<String>,
+    /// Its diagnostics are in the result.
+    pub checked: bool,
+    /// It was still analysing (or had not published for this change) when the wait ended.
+    pub incomplete: bool,
+    /// Asking it failed.
+    pub error: Option<String>,
+}
+
+/// Fresh diagnostics of a document, with every language server that serves it.
+#[derive(Clone, Debug, Default)]
+pub struct DocumentCheck {
+    pub diagnostics: Vec<Diagnostic>,
+    pub servers: Vec<CheckedServer>,
+}
+
 /// What became of one file.
 #[derive(Clone, Debug)]
 pub enum FileInspection {
@@ -198,6 +224,96 @@ impl LspManager {
         }
     }
 
+    /// Fresh diagnostics of the open document `doc`, whose text the caller just synced
+    /// (`changed`: at that instant, so diagnostics published before it are stale). Tells the
+    /// servers the document was saved, since checks that run on save (rust-analyzer's
+    /// `cargo check`) don't run for a change made outside the IDE, then waits for each server
+    /// to be ready, to answer for this text and to finish the background work it started, up
+    /// to `timeout`. Every server serving the document is reported, so a caller can tell "no
+    /// problems" from "nothing could check".
+    pub async fn check_document(
+        &self,
+        doc: DocId,
+        changed: Option<Instant>,
+        timeout: Duration,
+        cancel: &CancellationToken,
+    ) -> IdeResult<DocumentCheck> {
+        let snap = self.snapshot(doc)?;
+        let deadline = tokio::time::Instant::now() + timeout;
+        let left = || deadline.saturating_duration_since(tokio::time::Instant::now());
+        let ready = tokio::select! {
+            r = futures::future::join_all(snap.servers.iter().map(|s| s.wait_ready(left()))) => r,
+            () = cancel.cancelled() => return Err(IdeError::cancelled()),
+        };
+        // Once the servers have the document: a save sent while one starts would not reach it.
+        self.did_save(doc, snap.text.as_str());
+        let per_server = snap.servers.iter().zip(ready).map(|(server, run)| async {
+            let mut report = CheckedServer {
+                name: server.name.clone(),
+                status: server.status(),
+                message: server.status_message(),
+                checked: false,
+                incomplete: false,
+                error: None,
+            };
+            let Some(run) = run else { return Some((report, Vec::new())) };
+            let t = Target { server: server.clone(), run };
+            if !t.caps().restriction.diagnostics() {
+                return None;
+            }
+            let pull = t.caps().has("diagnosticProvider");
+            let mut since = changed;
+            let raw = loop {
+                // A pull asks for this text; a push server is waited on to publish for it.
+                let raw = if pull {
+                    server.wait_idle(left(), cancel).await;
+                    self.pull_diagnostics(&t, &snap.uri, cancel, left()).await
+                } else {
+                    let opts = InspectOptions { concurrency: 1, timeout: left(), settle: CHECK_SETTLE };
+                    wait_for_publish(server, &snap.path, since, opts, cancel).await
+                };
+                // The save may have started work (a `cargo check`) that publishes when it ends.
+                if raw.is_err() || pull || !server.is_busy() || left().is_zero() {
+                    break raw;
+                }
+                if !server.wait_idle(left(), cancel).await {
+                    break raw.map(|_| server.diagnostics_for(&snap.path));
+                }
+                // Idle: its last publish is final once quiet.
+                since = None;
+            };
+            report.status = server.status();
+            match raw {
+                Ok(items) => {
+                    report.checked = true;
+                    let fresh =
+                        pull || changed.is_none_or(|c| server.last_published(&snap.path).is_some_and(|p| p >= c));
+                    report.incomplete = !fresh || server.is_busy();
+                    let conv = self.conv(t.enc());
+                    let items = items
+                        .into_iter()
+                        .map(|d| convert::diagnostic(&conv, &snap.path, d, &t.server.name))
+                        .collect::<Vec<_>>();
+                    Some((report, items))
+                }
+                Err(e) => {
+                    report.error = Some(e.message);
+                    Some((report, Vec::new()))
+                }
+            }
+        });
+        let results = tokio::select! {
+            r = futures::future::join_all(per_server) => r,
+            () = cancel.cancelled() => return Err(IdeError::cancelled()),
+        };
+        let mut out = DocumentCheck::default();
+        for (report, items) in results.into_iter().flatten() {
+            out.servers.push(report);
+            out.diagnostics.extend(items);
+        }
+        Ok(out)
+    }
+
     async fn pull_diagnostics(
         &self,
         t: &Target,

crates/ide-lsp/src/lib.rs

@@ -40,7 +40,7 @@ mod vue_navigation;
 mod vue_refs;
 
 pub use injections::{InjectedRange, InjectionProvider, MAX_INJECTED_DOCUMENT_BYTES};
-pub use inspect::{FileInspection, InspectHost, InspectOptions};
+pub use inspect::{CheckedServer, DocumentCheck, FileInspection, InspectHost, InspectOptions};
 pub use jdtls::jvm_inspect::JdtJvmInspector;
 pub use kotlin_lsp::{KotlinDebugServer, KotlinDebugUnavailable};
 pub use launch::{LaunchError, Launcher, ProcessLauncher};

crates/ide-lsp/src/server.rs

@@ -658,6 +658,24 @@ impl Server {
         }
     }
 
+    /// Waits until no `$/progress` task is active, background work included (jdtls' builds,
+    /// rust-analyzer's `cargo check`), unlike [`Server::wait_indexed`]; false on timeout or
+    /// cancellation.
+    pub async fn wait_idle(&self, timeout: Duration, cancel: &CancellationToken) -> bool {
+        let deadline = tokio::time::Instant::now() + timeout;
+        loop {
+            let notified = self.phase_notify.notified();
+            if !self.is_busy() || self.running().is_none() {
+                return !self.is_busy();
+            }
+            tokio::select! {
+                () = notified => {}
+                () = tokio::time::sleep_until(deadline) => return !self.is_busy(),
+                () = cancel.cancelled() => return false,
+            }
+        }
+    }
+
     // ---- transiently opened files ----
 
     /// Registers a holder of the transient file `path` on instance `generation`;

crates/ide-lsp/tests/mock_server.rs

@@ -2178,6 +2178,57 @@ async fn missing_server_reports_once() {
     assert!(h.mgr.semantic_tokens(doc).await.unwrap().is_none());
 }
 
+#[tokio::test(flavor = "multi_thread")]
+async fn checking_a_document_saves_it_and_waits_for_fresh_diagnostics() {
+    let h = harness(&[("mock", incremental_caps())]);
+    let s = h.launcher.state("mock");
+    let (doc, path) = h.open("a.mk", "bad\n");
+    h.wait_status("mock", ServerStatus::Ready).await;
+    // The server answers the save with a publish, as an on-save check (`cargo check`) does.
+    let (server, uri) = (s.clone(), uri_of(&path));
+    let publisher = tokio::spawn(async move {
+        eventually(|| !server.notified("textDocument/didSave").is_empty()).await;
+        let diag = json!({ "range": {"start":{"line":0,"character":0},"end":{"line":0,"character":3}},
+                           "severity": 1, "message": "on save" });
+        server.peer().notify("textDocument/publishDiagnostics", json!({ "uri": uri, "diagnostics": [diag] })).unwrap();
+    });
+    let cancel = CancellationToken::new();
+    let changed = Some(std::time::Instant::now());
+    let check = h.mgr.check_document(doc, changed, Duration::from_secs(20), &cancel).await.unwrap();
+    publisher.await.unwrap();
+    assert_eq!(check.diagnostics.iter().map(|d| d.message.as_str()).collect::<Vec<_>>(), ["on save"]);
+    assert!(check.servers[0].checked && !check.servers[0].incomplete, "{:?}", check.servers);
+
+    // A change the server never answered: what it has is reported as not fresh.
+    let changed = Some(std::time::Instant::now());
+    let stale = h.mgr.check_document(doc, changed, Duration::from_millis(800), &cancel).await.unwrap();
+    assert!(stale.servers[0].checked && stale.servers[0].incomplete, "{:?}", stale.servers);
+    assert_eq!(stale.diagnostics.len(), 1);
+}
+
+#[tokio::test(flavor = "multi_thread")]
+async fn checking_a_document_reports_servers_that_cannot_check() {
+    let cancel = CancellationToken::new();
+    let h = harness(&[("ghost", json!({}))]);
+    h.launcher.state("ghost").missing.store(true, Ordering::SeqCst);
+    let (doc, _) = h.open("a.mk", "x");
+    h.wait_status("ghost", ServerStatus::Missing).await;
+    let check = h.mgr.check_document(doc, None, Duration::from_secs(5), &cancel).await.unwrap();
+    assert!(check.diagnostics.is_empty());
+    let s = &check.servers[0];
+    assert_eq!((s.name.as_str(), s.status, s.checked), ("ghost", ServerStatus::Missing, false));
+    assert_eq!(s.message.as_deref(), Some("install ghost"));
+
+    let h = harness(&[("mock", incremental_caps())]);
+    h.mgr.set_config_hook(Box::new(|cfg, _| cfg.launch_error = Some("needs JDK 21".into())));
+    let (doc, _) = h.open("a.mk", "x");
+    h.wait_status("mock", ServerStatus::Misconfigured).await;
+    let check = h.mgr.check_document(doc, None, Duration::from_secs(5), &cancel).await.unwrap();
+    assert_eq!(check.servers[0].status, ServerStatus::Misconfigured);
+    assert!(check.servers[0].message.as_deref().is_some_and(|m| m.contains("needs JDK 21")), "{:?}", check.servers);
+    assert!(!check.servers[0].checked);
+}
+
 #[tokio::test(flavor = "multi_thread")]
 async fn launch_error_fails_without_starting_the_server() {
     let h = harness(&[("mock", incremental_caps())]);

crates/ide-mcp/src/server.rs

@@ -3,17 +3,39 @@
 use crate::discovery::Discovery;
 use crate::{CancellationToken, PROJECT_HEADER, ToolRegistry, protocol};
 use bytes::Bytes;
-use http_body_util::{BodyExt, Full, Limited};
-use hyper::body::Incoming;
+use http_body_util::{BodyExt, Either, Full, Limited};
+use hyper::body::{Frame, Incoming};
 use hyper::header::{self, HeaderMap, HeaderValue};
 use hyper::{Method, Request, Response, StatusCode};
+use serde_json::{Value, json};
 use std::convert::Infallible;
 use std::path::{Path, PathBuf};
+use std::pin::Pin;
 use std::sync::Arc;
+use std::task::{Context, Poll};
+use std::time::Duration;
 use tokio::sync::watch;
+use tokio::task::{JoinError, JoinHandle};
+use tokio_util::sync::DropGuard;
 
 /// Largest request body.
 const MAX_BODY: usize = 8 << 20;
+/// A call still running after this long is answered on an event stream (when the client
+/// takes one), so that it can take as long as it needs: clients give up on a POST whose
+/// response has not started (Claude Code after a minute).
+#[cfg(not(test))]
+const STREAM_AFTER: Duration = Duration::from_secs(1);
+#[cfg(test)]
+const STREAM_AFTER: Duration = Duration::from_millis(100);
+/// How often a streamed call reports that it is still running: progress notifications reset
+/// the client's idle timeout (Claude Code's is five minutes).
+#[cfg(not(test))]
+const HEARTBEAT: Duration = Duration::from_secs(15);
+#[cfg(test)]
+const HEARTBEAT: Duration = Duration::from_millis(100);
+
+type Handled = Result<Option<Value>, Value>;
+type Body = Either<Full<Bytes>, EventStream>;
 
 struct Shared {
     registry: Arc<dyn ToolRegistry>,
@@ -140,15 +162,11 @@ async fn accept(listener: tokio::net::TcpListener, shared: Arc<Shared>, mut stop
     }
 }
 
-async fn serve(
-    req: Request<Incoming>,
-    shared: Arc<Shared>,
-    scope: String,
-) -> Result<Response<Full<Bytes>>, Infallible> {
+async fn serve(req: Request<Incoming>, shared: Arc<Shared>, scope: String) -> Result<Response<Body>, Infallible> {
     Ok(respond(req, &shared, scope).await)
 }
 
-type Reply = Response<Full<Bytes>>;
+type Reply = Response<Body>;
 
 async fn respond(req: Request<Incoming>, shared: &Arc<Shared>, scope: String) -> Reply {
     if req.uri().path() != "/mcp" {
@@ -163,7 +181,7 @@ async fn respond(req: Request<Incoming>, shared: &Arc<Shared>, scope: String) ->
         return response;
     }
     if req.method() != Method::POST {
-        // No server-sent event streams: every answer is in the POST's response.
+        // No stream of server-initiated messages: every answer is in the POST's response.
         let mut response = plain(StatusCode::METHOD_NOT_ALLOWED, "only POST");
         response.headers_mut().insert(header::ALLOW, HeaderValue::from_static("POST"));
         return response;
@@ -175,25 +193,41 @@ async fn respond(req: Request<Incoming>, shared: &Arc<Shared>, scope: String) ->
     }
     let scope = req.headers().get("mcp-session-id").and_then(|v| v.to_str().ok()).unwrap_or(&scope).to_owned();
     let project = project_of(&req);
+    let streams =
+        req.headers().get_all(header::ACCEPT).iter().any(|v| v.to_str().is_ok_and(|v| v.contains("text/event-stream")));
     let body = match Limited::new(req.into_body(), MAX_BODY).collect().await {
         Ok(body) => body.to_bytes(),
         Err(e) => return plain(StatusCode::PAYLOAD_TOO_LARGE, &format!("request body: {e}")),
     };
-    let initializing = serde_json::from_slice::<serde_json::Value>(&body)
-        .is_ok_and(|m| m.get("method").and_then(|v| v.as_str()) == Some("initialize"));
+    let message = serde_json::from_slice::<Value>(&body).ok();
+    let initializing = message.as_ref().is_some_and(|m| m.get("method").and_then(|v| v.as_str()) == Some("initialize"));
+    let id = message.as_ref().and_then(|m| m.get("id")).cloned().unwrap_or(Value::Null);
+    let progress_token = message.as_ref().and_then(|m| m.pointer("/params/_meta/progressToken")).cloned();
     let response_scope = scope.clone();
     let registry = shared.registry.clone();
     let shared = shared.clone();
     let cancel = shared.cancel.child_token();
-    let _guard = cancel.clone().drop_guard();
-    let handled = tokio::task::spawn_blocking(move || {
+    // Cancels the call when the client goes away (the response is dropped).
+    let guard = cancel.clone().drop_guard();
+    let mut handled = tokio::task::spawn_blocking(move || {
         protocol::handle_body(registry.as_ref(), project.as_deref(), &body, &shared.requests, &scope, cancel)
-    })
-    .await;
+    });
+    if streams && !initializing {
+        match tokio::time::timeout(STREAM_AFTER, &mut handled).await {
+            Ok(done) => return answer(done, false, &response_scope),
+            Err(_) => return event_stream(handled, id, progress_token, guard),
+        }
+    }
+    let done = handled.await;
+    drop(guard);
+    answer(done, initializing, &response_scope)
+}
+
+fn answer(handled: Result<Handled, JoinError>, initializing: bool, scope: &str) -> Reply {
     match handled {
         Ok(Ok(Some(reply))) => {
             let mut response = json(StatusCode::OK, &reply);
-            if initializing && let Ok(value) = HeaderValue::from_str(&response_scope) {
+            if initializing && let Ok(value) = HeaderValue::from_str(scope) {
                 response.headers_mut().insert("mcp-session-id", value);
             }
             response
@@ -204,6 +238,71 @@ async fn respond(req: Request<Incoming>, shared: &Arc<Shared>, scope: String) ->
     }
 }
 
+/// Answers a call that is still running on an event stream: a progress notification every
+/// [`HEARTBEAT`] while it runs (a comment when the client gave no progress token), then its
+/// answer. The call is cancelled as soon as the client goes away.
+fn event_stream(mut handled: JoinHandle<Handled>, id: Value, token: Option<Value>, guard: DropGuard) -> Reply {
+    let (tx, rx) = tokio::sync::mpsc::channel::<Bytes>(4);
+    tokio::spawn(async move {
+        let _guard = guard;
+        let started = tokio::time::Instant::now();
+        let mut beat = tokio::time::interval_at(started + HEARTBEAT, HEARTBEAT);
+        loop {
+            tokio::select! {
+                done = &mut handled => {
+                    let reply = match done {
+                        Ok(Ok(Some(reply)) | Err(reply)) => reply,
+                        Ok(Ok(None)) => return,
+                        Err(e) => protocol::error_response(id, -32603, &format!("the request failed: {e}")),
+                    };
+                    let _ = tx.send(event(&reply)).await;
+                    return;
+                }
+                _ = beat.tick() => {
+                    let elapsed = started.elapsed();
+                    let still_running = match &token {
+                        Some(token) => event(&json!({
+                            "jsonrpc": "2.0",
+                            "method": "notifications/progress",
+                            "params": {
+                                "progressToken": token,
+                                "progress": elapsed.as_secs_f64(),
+                                "message": format!("running for {}s", elapsed.as_secs()),
+                            },
+                        })),
+                        None => Bytes::from_static(b": running\n\n"),
+                    };
+                    if tx.send(still_running).await.is_err() {
+                        return;
+                    }
+                }
+                _ = tx.closed() => return,
+            }
+        }
+    });
+    let mut response = Response::new(Either::Right(EventStream(rx)));
+    response.headers_mut().insert(header::CONTENT_TYPE, HeaderValue::from_static("text/event-stream"));
+    response.headers_mut().insert(header::CACHE_CONTROL, HeaderValue::from_static("no-cache"));
+    response
+}
+
+/// One server-sent event carrying a JSON-RPC message.
+fn event(message: &Value) -> Bytes {
+    Bytes::from(format!("event: message\ndata: {message}\n\n"))
+}
+
+/// A `text/event-stream` body, written by [`event_stream`]'s task.
+pub(crate) struct EventStream(tokio::sync::mpsc::Receiver<Bytes>);
+
+impl hyper::body::Body for EventStream {
+    type Data = Bytes;
+    type Error = Infallible;
+
+    fn poll_frame(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Result<Frame<Bytes>, Infallible>>> {
+        self.get_mut().0.poll_recv(cx).map(|data| data.map(|data| Ok(Frame::data(data))))
+    }
+}
+
 /// No `Origin` other than this server's own, and a loopback `Host`: a web
 /// page (DNS rebinding) can't reach the tools even before the token check.
 fn local_request(headers: &HeaderMap, port: u16) -> bool {
@@ -242,22 +341,22 @@ fn project_of(req: &Request<Incoming>) -> Option<String> {
     })
 }
 
-fn plain(status: StatusCode, text: &str) -> Response<Full<Bytes>> {
-    let mut response = Response::new(Full::new(Bytes::from(text.to_owned())));
+fn plain(status: StatusCode, text: &str) -> Reply {
+    let mut response = Response::new(Either::Left(Full::new(Bytes::from(text.to_owned()))));
     *response.status_mut() = status;
     response.headers_mut().insert(header::CONTENT_TYPE, HeaderValue::from_static("text/plain; charset=utf-8"));
     response
 }
 
-fn json(status: StatusCode, value: &serde_json::Value) -> Response<Full<Bytes>> {
-    let mut response = Response::new(Full::new(Bytes::from(value.to_string())));
+fn json(status: StatusCode, value: &Value) -> Reply {
+    let mut response = Response::new(Either::Left(Full::new(Bytes::from(value.to_string()))));
     *response.status_mut() = status;
     response.headers_mut().insert(header::CONTENT_TYPE, HeaderValue::from_static("application/json"));
     response
 }
 
-fn empty(status: StatusCode) -> Response<Full<Bytes>> {
-    let mut response = Response::new(Full::new(Bytes::new()));
+fn empty(status: StatusCode) -> Reply {
+    let mut response = Response::new(Either::Left(Full::new(Bytes::new())));
     *response.status_mut() = status;
     response
 }
@@ -265,6 +364,134 @@ fn empty(status: StatusCode) -> Response<Full<Bytes>> {
 #[cfg(test)]
 mod tests {
     use super::*;
+    use std::sync::atomic::{AtomicBool, Ordering};
+    use tokio::io::{AsyncReadExt, AsyncWriteExt};
+
+    /// `slow` sleeps `ms` milliseconds; `wait` runs until it is cancelled, which it records.
+    struct Slow(Arc<AtomicBool>);
+
+    impl ToolRegistry for Slow {
+        fn projects(&self) -> Vec<PathBuf> {
+            vec![PathBuf::from("/project")]
+        }
+        fn tools(&self, _: &Path) -> Result<Vec<crate::Tool>, String> {
+            Ok(Vec::new())
+        }
+        fn call(
+            &self,
+            _: &Path,
+            name: &str,
+            arguments: &str,
+            cancel: CancellationToken,
+        ) -> Result<String, crate::ToolCallError> {
+            if name == "wait" {
+                while !cancel.is_cancelled() {
+                    std::thread::sleep(Duration::from_millis(10));
+                }
+                self.0.store(true, Ordering::SeqCst);
+                return Err(crate::ToolCallError::Failed("cancelled".into()));
+            }
+            let ms = serde_json::from_str::<Value>(arguments).unwrap()["ms"].as_u64().unwrap();
+            std::thread::sleep(Duration::from_millis(ms));
+            Ok("done".into())
+        }
+    }
+
+    fn start() -> (McpServer, Arc<AtomicBool>) {
+        let cancelled = Arc::new(AtomicBool::new(false));
+        let registry = Arc::new(Slow(cancelled.clone()));
+        (McpServer::start(registry, None, &tokio::runtime::Handle::current()).unwrap(), cancelled)
+    }
+
+    fn call(name: &str, ms: u64, token: Option<&str>) -> Value {
+        let mut params = json!({ "name": name, "arguments": { "ms": ms } });
+        if let Some(token) = token {
+            params["_meta"] = json!({ "progressToken": token });
+        }
+        json!({ "jsonrpc": "2.0", "id": 3, "method": "tools/call", "params": params })
+    }
+
+    async fn send(server: &McpServer, accept: &str, body: &Value) -> tokio::net::TcpStream {
+        let body = body.to_string();
+        let port = server.port();
+        let mut stream = tokio::net::TcpStream::connect(("127.0.0.1", port)).await.unwrap();
+        let request = format!(
+            "POST /mcp HTTP/1.1\r\nHost: 127.0.0.1:{port}\r\nAuthorization: Bearer {}\r\nContent-Type: application/json\r\nAccept: {accept}\r\nContent-Length: {}\r\nConnection: close\r\n\r\n{body}",
+            server.token(),
+            body.len()
+        );
+        stream.write_all(request.as_bytes()).await.unwrap();
+        stream
+    }
+
+    /// The whole response, lowercased headers and the body as sent (chunked or not).
+    async fn exchange(server: &McpServer, accept: &str, body: &Value) -> (String, String) {
+        let mut out = String::new();
+        send(server, accept, body).await.read_to_string(&mut out).await.unwrap();
+        let (head, body) = out.split_once("\r\n\r\n").unwrap();
+        (head.to_ascii_lowercase(), body.to_owned())
+    }
+
+    fn events(body: &str) -> Vec<Value> {
+        body.lines().filter_map(|l| l.strip_prefix("data: ")).map(|d| serde_json::from_str(d).unwrap()).collect()
+    }
+
+    const BOTH: &str = "application/json, text/event-stream";
+
+    #[tokio::test(flavor = "multi_thread")]
+    async fn long_calls_are_answered_on_an_event_stream_that_reports_progress() {
+        let (server, _) = start();
+
+        let (head, body) = exchange(&server, BOTH, &call("slow", 0, Some("p"))).await;
+        assert!(head.contains("content-type: application/json"), "{head}");
+        assert_eq!(serde_json::from_str::<Value>(&body).unwrap()["result"]["content"][0]["text"], "done");
+
+        let (head, body) = exchange(&server, BOTH, &call("slow", 450, Some("p"))).await;
+        assert!(head.contains("content-type: text/event-stream"), "{head}");
+        let messages = events(&body);
+        let (answer, progress) = messages.split_last().unwrap();
+        assert_eq!(answer["id"], 3);
+        assert_eq!(answer["result"]["content"][0]["text"], "done");
+        assert!(progress.len() >= 2, "{body}");
+        for pair in progress.windows(2) {
+            assert!(pair[0]["params"]["progress"].as_f64() < pair[1]["params"]["progress"].as_f64(), "{body}");
+        }
+        for p in progress {
+            assert_eq!((&p["method"], &p["params"]["progressToken"]), (&json!("notifications/progress"), &json!("p")));
+        }
+
+        // Without a progress token, comments keep the stream going.
+        let (_, body) = exchange(&server, BOTH, &call("slow", 300, None)).await;
+        assert!(body.contains(": running"), "{body}");
+        assert_eq!(events(&body).len(), 1, "{body}");
+
+        // A client that takes only JSON waits for it.
+        let (head, body) = exchange(&server, "application/json", &call("slow", 300, Some("p"))).await;
+        assert!(head.contains("content-type: application/json"), "{head}");
+        assert_eq!(serde_json::from_str::<Value>(&body).unwrap()["id"], 3);
+    }
+
+    #[tokio::test(flavor = "multi_thread")]
+    async fn a_streamed_call_is_cancelled_when_the_client_goes_away() {
+        let (server, cancelled) = start();
+        let mut stream = send(&server, BOTH, &call("wait", 0, Some("p"))).await;
+        let mut head = Vec::new();
+        while !String::from_utf8_lossy(&head).contains("\r\n\r\n") {
+            let mut buf = [0u8; 1024];
+            let n = stream.read(&mut buf).await.unwrap();
+            assert!(n > 0, "the stream ended early");
+            head.extend_from_slice(&buf[..n]);
+        }
+        assert!(String::from_utf8_lossy(&head).to_ascii_lowercase().contains("text/event-stream"));
+        drop(stream);
+        tokio::time::timeout(Duration::from_secs(10), async {
+            while !cancelled.load(Ordering::SeqCst) {
+                tokio::time::sleep(Duration::from_millis(20)).await;
+            }
+        })
+        .await
+        .expect("the call was cancelled");
+    }
 
     #[test]
     fn only_loopback_hosts_and_origins_of_this_server_pass() {

crates/ide-mcp/src/stdio.rs

@@ -35,7 +35,8 @@ pub fn run(discovery: &Path, project: Option<PathBuf>) -> i32 {
 }
 
 /// Relays each line of `input` (a JSON-RPC message or batch) to the IDE and
-/// writes its answer, if any, as one line to `output`.
+/// writes what it answers, if anything, one message per line to `output`: the
+/// answer, and before it the progress notifications of a long call.
 pub async fn bridge<R, W>(discovery: &Path, project: &Path, input: R, mut output: W) -> std::io::Result<()>
 where
     R: AsyncBufRead + Unpin,
@@ -44,23 +45,37 @@ where
     let scope = crate::server::new_token()?;
     let mut lines = input.lines();
     let mut pending = tokio::task::JoinSet::new();
+    let (sent, mut received) = tokio::sync::mpsc::unbounded_channel::<Value>();
     let mut eof = false;
     loop {
+        if eof && pending.is_empty() && received.is_empty() {
+            break;
+        }
         let reply = tokio::select! {
             line = lines.next_line(), if !eof => {
                 let Some(line) = line? else { eof = true; continue };
                 if line.trim().is_empty() { continue; }
                 match serde_json::from_str::<Value>(&line) {
                     Ok(message) => {
-                        let (discovery, project, scope) = (discovery.to_owned(), project.to_owned(), scope.clone());
-                        pending.spawn(async move { relay(&discovery, &project, &message, &scope).await });
+                        let (discovery, project, scope, sent) =
+                            (discovery.to_owned(), project.to_owned(), scope.clone(), sent.clone());
+                        pending.spawn(async move {
+                            if let Some(reply) = relay(&discovery, &project, &message, &scope, &sent).await {
+                                let _ = sent.send(reply);
+                            }
+                        });
                         continue;
                     }
                     Err(e) => Some(error_response(Value::Null, -32700, &format!("not JSON: {e}"))),
                 }
             }
-            reply = pending.join_next(), if !pending.is_empty() => match reply { Some(reply) => reply.map_err(std::io::Error::other)?, None => None },
-            else => break,
+            Some(message) = received.recv() => Some(message),
+            done = pending.join_next(), if !pending.is_empty() => {
+                if let Some(Err(e)) = done {
+                    return Err(std::io::Error::other(e));
+                }
+                continue;
+            }
         };
         if let Some(reply) = reply {
             output.write_all(reply.to_string().as_bytes()).await?;
@@ -72,15 +87,24 @@ where
 }
 
 /// The IDE's answer to `message`, or an error response for each request in
-/// it when the IDE can't be reached.
-async fn relay(discovery: &Path, project: &Path, message: &Value, scope: &str) -> Option<Value> {
-    let failure = match post(discovery, project, message, scope).await {
-        Ok((StatusCode::ACCEPTED, _)) => return None,
-        Ok((_, body)) if !body.is_empty() => match serde_json::from_slice::<Value>(&body) {
+/// it when the IDE can't be reached. An answer on an event stream goes to `sent`
+/// with the messages before it.
+async fn relay(
+    discovery: &Path,
+    project: &Path,
+    message: &Value,
+    scope: &str,
+    sent: &tokio::sync::mpsc::UnboundedSender<Value>,
+) -> Option<Value> {
+    let failure = match post(discovery, project, message, scope, sent).await {
+        Ok(Answer::Streamed { answered: true }) => return None,
+        Ok(Answer::Streamed { answered: false }) => "OpenIDEA's answer ended early".to_owned(),
+        Ok(Answer::Body(StatusCode::ACCEPTED, _)) => return None,
+        Ok(Answer::Body(_, body)) if !body.is_empty() => match serde_json::from_slice::<Value>(&body) {
             Ok(reply) => return Some(reply),
             Err(_) => String::from_utf8_lossy(&body).trim().to_owned(),
         },
-        Ok((status, _)) => format!("OpenIDEA answered {status}"),
+        Ok(Answer::Body(status, _)) => format!("OpenIDEA answered {status}"),
         Err(e) => e,
     };
     let errors: Vec<Value> = requests(message).into_iter().map(|id| error_response(id, NOT_OPEN, &failure)).collect();
@@ -100,9 +124,23 @@ fn requests(message: &Value) -> Vec<Value> {
     }
 }
 
+enum Answer {
+    Body(StatusCode, Bytes),
+    /// The messages of an event stream went to the channel; `answered`: one was a response.
+    Streamed {
+        answered: bool,
+    },
+}
+
 /// POSTs `message` to the server in the discovery file; a message for the
 /// user when that fails.
-async fn post(discovery: &Path, project: &Path, message: &Value, scope: &str) -> Result<(StatusCode, Bytes), String> {
+async fn post(
+    discovery: &Path,
+    project: &Path,
+    message: &Value,
+    scope: &str,
+    sent: &tokio::sync::mpsc::UnboundedSender<Value>,
+) -> Result<Answer, String> {
     let not_running = || {
         format!(
             "OpenIDEA's MCP server is not running. Start OpenIDEA, open {} in it, and turn on Settings › Agents › MCP Server",
@@ -125,6 +163,60 @@ async fn post(discovery: &Path, project: &Path, message: &Value, scope: &str) ->
         .map_err(|e| e.to_string())?;
     let response = sender.send_request(request).await.map_err(|e| format!("cannot reach OpenIDEA: {e}"))?;
     let status = response.status();
-    let body = response.into_body().collect().await.map_err(|e| format!("OpenIDEA's answer: {e}"))?.to_bytes();
-    Ok((status, body))
+    let streamed = response
+        .headers()
+        .get(header::CONTENT_TYPE)
+        .is_some_and(|v| v.to_str().is_ok_and(|v| v.starts_with("text/event-stream")));
+    let mut body = response.into_body();
+    if !streamed {
+        let body = body.collect().await.map_err(|e| format!("OpenIDEA's answer: {e}"))?.to_bytes();
+        return Ok(Answer::Body(status, body));
+    }
+    let (mut buffer, mut answered) = (Vec::new(), false);
+    while let Some(frame) = body.frame().await {
+        let frame = frame.map_err(|e| format!("OpenIDEA's answer: {e}"))?;
+        let Ok(data) = frame.into_data() else { continue };
+        buffer.extend_from_slice(&data);
+        for data in take_events(&mut buffer) {
+            if let Ok(message) = serde_json::from_str::<Value>(&data) {
+                answered |= message.get("method").is_none();
+                let _ = sent.send(message);
+            }
+        }
+    }
+    Ok(Answer::Streamed { answered })
+}
+
+/// The `data` of each complete server-sent event at the start of `buffer`, which keeps
+/// the rest. Comments and other fields are skipped.
+fn take_events(buffer: &mut Vec<u8>) -> Vec<String> {
+    let mut events = Vec::new();
+    while let Some(end) = buffer.windows(2).position(|w| w == b"\n\n") {
+        let block: Vec<u8> = buffer.drain(..end + 2).collect();
+        let block = String::from_utf8_lossy(&block).replace("\r\n", "\n");
+        let data: Vec<&str> = block
+            .lines()
+            .filter_map(|line| line.strip_prefix("data:"))
+            .map(|d| d.strip_prefix(' ').unwrap_or(d))
+            .collect();
+        if !data.is_empty() {
+            events.push(data.join("\n"));
+        }
+    }
+    events
+}
+
+#[cfg(test)]
+mod tests {
+    use super::take_events;
+
+    #[test]
+    fn events_are_taken_whole_and_comments_skipped() {
+        let mut buffer = b": running\n\nevent: message\ndata: {\"a\":1}\n\nevent: message\ndata: {\"b\"".to_vec();
+        assert_eq!(take_events(&mut buffer), ["{\"a\":1}"]);
+        assert_eq!(buffer, b"event: message\ndata: {\"b\"");
+        buffer.extend_from_slice(b":2}\n\n");
+        assert_eq!(take_events(&mut buffer), ["{\"b\":2}"]);
+        assert!(buffer.is_empty());
+    }
 }

crates/ide-mcp/tests/server.rs

@@ -39,6 +39,10 @@ impl ToolRegistry for Registry {
         match name {
             "echo" if args["text"] == "fail" => Err(ToolCallError::Failed("it failed".into())),
             "echo" => Ok(format!("{} in {}", args["text"].as_str().unwrap_or(""), project.display())),
+            "sleep" => {
+                std::thread::sleep(std::time::Duration::from_millis(args["ms"].as_u64().unwrap()));
+                Ok("slept".into())
+            }
             _ => Err(ToolCallError::UnknownTool(format!("no tool {name:?}"))),
         }
     }
@@ -252,6 +256,20 @@ async fn the_stdio_bridge_relays_lines_and_explains_a_missing_ide() {
     assert!(reply["error"]["message"].as_str().unwrap().contains("MCP server is not running"), "{reply}");
 }
 
+#[tokio::test(flavor = "multi_thread")]
+async fn the_stdio_bridge_relays_a_long_call_answered_on_an_event_stream() {
+    let s = setup();
+    let call = json!({ "jsonrpc": "2.0", "id": 4, "method": "tools/call",
+        "params": { "name": "sleep", "arguments": { "ms": 1500 }, "_meta": { "progressToken": 4 } } });
+    let mut output = Vec::new();
+    stdio::bridge(&s.discovery, &s.project, format!("{call}\n").as_bytes(), &mut output).await.unwrap();
+    let replies: Vec<Value> =
+        String::from_utf8(output).unwrap().lines().map(|l| serde_json::from_str(l).unwrap()).collect();
+    let answer = replies.last().unwrap();
+    assert_eq!(answer["id"], 4, "{replies:?}");
+    assert_eq!(answer["result"]["content"][0]["text"], "slept");
+}
+
 #[tokio::test(flavor = "multi_thread")]
 async fn routing_an_argument_overrides_the_header_and_ambiguity_lists_projects() {
     struct Many(Vec<PathBuf>);

crates/ide-plugin/src/runtime.rs

@@ -55,7 +55,7 @@ use views_bindings::exports::openidea::plugin::view_provider as wit_view;
 use views_bindings::openidea::plugin::view_types as wit_vt;
 
 /// The API version of the world above, `major.minor` of [`host_api`].
-pub const API_VERSION: &str = "1.6";
+pub const API_VERSION: &str = "1.7";
 const EPOCH_TICK: Duration = Duration::from_millis(10);
 pub(crate) const MAX_TEXT: usize = 1 << 20;
 pub(crate) const MAX_TITLE: usize = 256;
@@ -170,6 +170,11 @@ pub trait HostApi: Send + Sync {
         let _ = (client, tab, cancel, timeout);
         Err(HostError::Failed("content tabs unavailable".into()))
     }
+    /// Opens a diff of two texts in the invoking window.
+    fn open_diff(&self, client: &str, diff: crate::ContentDiff, file_name: Option<String>) -> Result<(), HostError> {
+        let _ = (client, diff, file_name);
+        Err(HostError::Failed("diffs unavailable".into()))
+    }
     /// Answers a content action in the invoking window.
     fn reply_content_tab(&self, client: &str, request: &str, reply: crate::ContentTabReply) -> Result<(), HostError> {
         let _ = (client, request, reply);

crates/ide-plugin/src/wit_host.rs

@@ -1770,6 +1770,12 @@ impl views::Host for StoreData {
             )
             .map_err(to_wit))
     }
+    fn open_diff(&mut self, diff: views::ContentDiff, file_name: Option<String>) -> Fallible<()> {
+        if let Err(e) = self.require_window() {
+            return Ok(Err(e));
+        }
+        Ok(self.host.open_diff(self.invocation.client.as_deref().unwrap(), diff.into(), file_name).map_err(to_wit))
+    }
     fn reply_content_tab(&mut self, request_id: String, reply: views::ContentTabReply) -> Fallible<()> {
         if let Err(e) = self.require_window() {
             return Ok(Err(e));

crates/ide-plugin/tests/api_compat.rs

@@ -91,15 +91,15 @@ fn the_sdk_carries_the_hosts_wit() {
 
 #[test]
 fn the_version_check_runs_compatible_components_and_explains_the_rest() {
-    let host = v("1.6.0");
-    for ok in ["1.0.0", "1.3.0", "1.4.7", "1.5.0", "1.6.0", "1.0.0-rc.1"] {
+    let host = v("1.7.0");
+    for ok in ["1.0.0", "1.3.0", "1.4.7", "1.5.0", "1.6.0", "1.7.0", "1.0.0-rc.1"] {
         assert_eq!(check_api(&v(ok), &host), Ok(()), "{ok}");
     }
-    let newer = check_api(&v("1.7.0"), &host).unwrap_err();
-    assert!(newer.contains("1.7") && newer.contains("update OpenIDEA"), "{newer}");
+    let newer = check_api(&v("1.8.0"), &host).unwrap_err();
+    assert!(newer.contains("1.8") && newer.contains("update OpenIDEA"), "{newer}");
     assert!(check_api(&v("2.0.0"), &host).unwrap_err().contains("update OpenIDEA"));
     let older = check_api(&v("0.2.0"), &host).unwrap_err();
-    assert!(older.contains("rebuild it with the 1.6 SDK"), "{older}");
+    assert!(older.contains("rebuild it with the 1.7 SDK"), "{older}");
     // 0.x: every minor is its own API.
     assert_eq!(check_api(&v("0.2.0"), &v("0.2.5")), Ok(()));
     assert!(check_api(&v("0.1.0"), &v("0.2.0")).is_err());

crates/ide-plugin/tests/fixtures/api14/dist/plugin.wasm.sources

@@ -1 +1 @@
-005d9da29eb7d713a97ff872051e408f653030434d837835843298553c9e12e0
+3c7f35facd15ee8380ccb6475b7c051d500e38346b711e1805077becd0c75f75

crates/ide-plugin/tests/fixtures/commit/dist/plugin.wasm.sources

@@ -1 +1 @@
-6359ef4271f38374889412bd926d9aa735f59a8ce047ffcb06c47976444196cf
+3879822d975695c6258e95286b0e64c5ee1e3265876501efaf0e577b38f8222b

crates/ide-plugin/tests/fixtures/data-tools/dist/plugin.wasm.sources

@@ -1 +1 @@
-6f560f3d0d7737150d2dfa09c3b801bd3b4c3a52cef9893ed8fc045809fe33e1
+228ae888bf556ce5cedc7843eb20e92f221d9e1f640f3c6c595bed3fd6be6051

crates/ide-plugin/tests/fixtures/detail-views/dist/plugin.wasm.sources

@@ -1 +1 @@
-4024af2d55d7fe4e8c456efd7e0c497ade4b2c5959e9108ff218f4a669e920f4
+41de239b6f723020b38eb2b67f642b7c88cc88c79117c3072ba122633afc418c

crates/ide-plugin/tests/fixtures/diagnostics/dist/plugin.wasm.sources

@@ -1 +1 @@
-4ca977f53a18e9e8f869d34e027a15abece9e97b9331e23d4f71af721b104611
+78c5ed3c756498c7619b46c3622ae7a59461c61c747b45caecd79b341ee654de

crates/ide-plugin/tests/fixtures/endpoints/dist/plugin.wasm.sources

@@ -1 +1 @@
-3d12a00f81e0db1b0902c2ddebfd6454a056f15b97add80b22a0333722568dc8
+ee848321e53cb181536e6158570dbb4ab02a6fd2a1a064b068803ac7da7f3448

crates/ide-plugin/tests/fixtures/execution/dist/plugin.wasm.sources

@@ -1 +1 @@
-95d89e411216f50d0b34bee110c6bfc9b8fbcb2ffaae2e912c3609f7bf678b2c
+b587de945875a98f1d4ca20fab7cf94fb4dc6d848136aa19ab0e0e5319155a80

crates/ide-plugin/tests/fixtures/execution/plugin.toml

@@ -40,6 +40,10 @@ title = "write"
 id = "content"
 title = "content"
 
+[[contributes.commands]]
+id = "diff"
+title = "diff"
+
 [[contributes.commands]]
 id = "events"
 title = "events"

crates/ide-plugin/tests/fixtures/execution/src/lib.rs

@@ -78,6 +78,18 @@ impl Plugin for Execution {
                 })?;
                 Ok(None)
             }
+            "diff" => {
+                host::open_diff(
+                    &ContentDiff {
+                        left: "before\n".into(),
+                        right: "after\n".into(),
+                        title: Some("Review".into()),
+                        ..Default::default()
+                    },
+                    Some("src/review.rs"),
+                )?;
+                Ok(None)
+            }
             "events" => host::storage::get("events"),
             "validation" => host::storage::get("validation"),
             _ => Err(Error::NotFound(id.into())),

crates/ide-plugin/tests/fixtures/ext-owner/dist/plugin.wasm.sources

@@ -1 +1 @@
-dd4b6c5153892a4f3facb3f23cb1d92da39a3977985b8abf4eaa9558decfa4a9
+1c8776dcae35d2d49dd6c1e32b0cdd354de1eb0f72a473245a2c47368b89ec30

crates/ide-plugin/tests/fixtures/file-templates/dist/plugin.wasm.sources

@@ -1 +1 @@
-325bc15cd28933d9687bc3c316008f921f48a4a69d7528c6b367fa0ff22489b8
+2a517cbffd6d3cdda37117d8ca8815978a09995923fc3d5aa5af7020afdac56a

crates/ide-plugin/tests/fixtures/files-events/dist/plugin.wasm.sources

@@ -1 +1 @@
-abe706392e04ef5a14f9feab88e0c0d6a9e96bee7de771b61deeb65e7d9e0a7c
+dbd912b1f8488ecd446af07b5dcaef55d44bce57c1a55be5c0b0fb33e2697903

crates/ide-plugin/tests/fixtures/grouped-views/dist/plugin.wasm.sources

@@ -1 +1 @@
-fb3677946021b30d226e2e3d422c352645c2065c93057c0a645246520860fc90
+efdc84cd2bedb3989b03d19b569d09958f26e502db65db4dd786eb3438a7c407

crates/ide-plugin/tests/fixtures/hello/dist/plugin.wasm.sources

@@ -1 +1 @@
-a01852ead9004ac1558028da19a1ae96ccd035775484089fd39f14263082daf1
+be6bc15ee42a5e21781ba54f548007351a46b669882ee4491da20ff556927a06

crates/ide-plugin/tests/fixtures/hover/dist/plugin.wasm.sources

@@ -1 +1 @@
-bf00050b7bb9911680a94fd36aaeb83fc96d94030e8ceef51d1723c3950253f9
+e5c3a3beda750dff27d7b823676d53f15b7c76b8ad539594cd913bd178d750da

crates/ide-plugin/tests/fixtures/indexer/dist/plugin.wasm.sources

@@ -1 +1 @@
-d00a07d9d51e7ca117cec59070d2812d4d1efb2730b60a6f171c8fd12903d055
+322de3299f0413101c02358836e7df7e06e58cbb22c11897664564abbb8af090

crates/ide-plugin/tests/fixtures/inlay-hints/dist/plugin.wasm.sources

@@ -1 +1 @@
-0aa0ee56e8bacd4d218bafecdec7f4b6249381fad6e31f8b2ee89fd88b16d710
+d768ff6a4a466cc6f1d72499df3ccb4ae76872436b8eddff27f62aa156331a37

crates/ide-plugin/tests/fixtures/jobs/dist/plugin.wasm.sources

@@ -1 +1 @@
-e06955818969808e6695fba9178727239e343bc4542efbf56262dd407175fd8a
+57aea107b2c10e4d30fa3785ac4c6566f1b40908a18a3859aca8be047fac9518

crates/ide-plugin/tests/fixtures/language-features/dist/plugin.wasm.sources

@@ -1 +1 @@
-7af67673471d49f97aa2cc131b5deddfc78ee7fc203901eba12f4970a5b13f75
+c98bcc89750e26e738d7115a7c0454fde25367a0a23bdc2ff95fb5a5dacc9f98

crates/ide-plugin/tests/fixtures/misbehave/dist/plugin.wasm.sources

@@ -1 +1 @@
-e81d2454a61977ab69dc8b5c3c617627c559c4e340337a3d43309daeb9b1c12d
+a4c23b93a14eda705cb18c88bbc2373d1ef3f96031ff2df21b8b092b50633996

crates/ide-plugin/tests/fixtures/misbehave/src/lib.rs

@@ -5,9 +5,9 @@ wit_bindgen::generate!({
     inline: "
         package fixture:misbehave;
         world misbehave {
-            include openidea:plugin/plugin-syntax@1.6.0;
-            export openidea:plugin/providers@1.6.0;
-            export openidea:plugin/file-actions@1.6.0;
+            include openidea:plugin/plugin-syntax@1.7.0;
+            export openidea:plugin/providers@1.7.0;
+            export openidea:plugin/file-actions@1.7.0;
         }
     ",
     path: "../../../../../wit",

crates/ide-plugin/tests/fixtures/path-events/dist/plugin.wasm.sources

@@ -1 +1 @@
-123ae68df6baa3b5983349ba05fb441ec67fddcb32cab566b0d02e443bb4800e
+aec002b3dd310068e69a6ae67a49d30655bf8baea9153a110a407e9d408e6880

crates/ide-plugin/tests/fixtures/private-dir/dist/plugin.wasm.sources

@@ -1 +1 @@
-7b26a4ec36b496f9a4f5e029ef557707961a281e31508863c989a5a5abd5e225
+08ece563c3b55c2b86e68fbb0815ddcbb63beb6f1f6c32b8dbdbee558a4a66c1

crates/ide-plugin/tests/fixtures/semantic-tokens/dist/plugin.wasm.sources

@@ -1 +1 @@
-67f278ade12d11b1445ac3d448853ec46282f2f3e2b2299c6c8fe0dfb4fc86cd
+450845edf234a1cc78cd6cfc0b812a89f3a2e41484689cc1e1b05be66873d4eb

crates/ide-plugin/tests/fixtures/settings-pages/dist/plugin.wasm.sources

@@ -1 +1 @@
-8cf9210844a1968f485e6e747f6dff4a1fdf0a628e2945f731d8289dd01f8385
+61b735de5ef61dcd0ea8e640c2ad004e84a63fe4dfd7872ffb5e04d6d81dc9a9

crates/ide-plugin/tests/fixtures/storage/dist/plugin.wasm.sources

@@ -1 +1 @@
-263e6ab4b54593f09ae2cf71e9a191acb95ed744cc16bbaf9a9263e41614e99a
+36776367782eaa4b8b8121f4a665dd8e68525a4836bff1c92bc16770cce14929

crates/ide-plugin/tests/fixtures/symbols/dist/plugin.wasm.sources

@@ -1 +1 @@
-682a712b6c75ad0c0da24476f87c77a76b248c201d4d31923a79fda053b76b90
+f6311d232a99356b02a398b2ce3db0865c425f435a8d201157719178ba2b97c7

crates/ide-plugin/tests/fixtures/tables/dist/plugin.wasm.sources

@@ -1 +1 @@
-c5718b3978f21291cfff7a00233ba68d545a5977bc3e90c546b4380528295446
+fe1d26665e3c816ed43fc720acabad03a37b7924bccd4dd8c357fd156947b3c7

crates/ide-plugin/tests/fixtures/web-content/dist/plugin.wasm.sources

@@ -1 +1 @@
-186b30c785fae23d18c5efe8fa63f6526d23d9d141580deef7ee7009310a88c3
+76bab8e48235f9f066f5b9bbfdd9398916b6c3ed73c072c543d80595130519f7

crates/ide-plugin/tests/fixtures/web-log/dist/plugin.wasm.sources

@@ -1 +1 @@
-cb3a1c4a0518aa3f3e689337e8f4249180e5b3753b0e7bfaba8c974f89f6ef7a
+f9ed2eac306229f76b05d0c4a4fb2f0ed8d81a1dfc5eb50d044bbe10c9206a5f

crates/ide-plugin/tests/fixtures/web-pty/dist/plugin.wasm.sources

@@ -1 +1 @@
-fa97682ca30cb0ad1392ff1bab4d99ea6d9ccb2654feedfdc130d11adb7df93b
+f2d83d9f56da072d38a1552195af8a9d4edc11888c645627d5dd1e4a46afc4df

crates/ide-run/src/process.rs

@@ -498,7 +498,8 @@ impl ProcessManager {
                     None,
                 )?;
             }
-            spawn_pump(rx, on_output.clone(), entry.clone(), sink, options.encoding.clone(), notice)?;
+            let decoder = || OutputDecoder::for_pipes(options.encoding.as_deref());
+            spawn_pump(rx, on_output.clone(), entry.clone(), sink, [decoder(), decoder()], notice)?;
             Ok(())
         })();
         if let Err(e) = result {
@@ -629,7 +630,10 @@ impl ProcessManager {
             #[cfg(unix)]
             Some(Box::new(wait_readable)),
         )
-        .and_then(|_| spawn_pump(rx, on_output, entry.clone(), sink, options.encoding.clone(), None));
+        .and_then(|_| {
+            let decoder = || OutputDecoder::for_label(options.encoding.as_deref());
+            spawn_pump(rx, on_output, entry.clone(), sink, [decoder(), decoder()], None)
+        });
         if let Err(e) = result {
             let _ = child.kill();
             let _ = child.wait();
@@ -1120,18 +1124,35 @@ fn chunk(stream: Stream, text: String) -> OutputChunk {
     }
 }
 
+/// Appends what `decode` writes to `pending`, through the notice filter when there is one.
+fn emit(
+    decode: impl FnOnce(&mut String),
+    notice: &mut Option<ide_core::output_encoding::NoticeFilter>,
+    decoded: &mut String,
+    pending: &mut String,
+) {
+    match notice {
+        Some(filter) => {
+            decode(decoded);
+            filter.filter(decoded, pending);
+            decoded.clear();
+        }
+        None => decode(pending),
+    }
+}
+
 /// Merges both streams in arrival order, batching consecutive output of the same stream.
+/// `decoders` decode stdout and stderr.
 fn spawn_pump(
     rx: mpsc::Receiver<Msg>,
     on_output: OutputFn,
     entry: Arc<Entry>,
     sink: SharedSink,
-    encoding: Option<String>,
+    decoders: [OutputDecoder; 2],
     notice: Option<String>,
 ) -> std::io::Result<()> {
     std::thread::Builder::new().name(format!("openidea-run-pump-{}", entry.id.0)).spawn(move || {
-        let mut out_dec = OutputDecoder::for_label(encoding.as_deref());
-        let mut err_dec = OutputDecoder::for_label(encoding.as_deref());
+        let [mut out_dec, mut err_dec] = decoders;
         // "Picked up JAVA_TOOL_OPTIONS: …" from every JVM given the console encoding, on
         // either stream (`spring-boot:run` copies its fork's stderr to Maven's stdout).
         let filter = || notice.clone().map(ide_core::output_encoding::NoticeFilter::new);
@@ -1140,6 +1161,8 @@ fn spawn_pump(
         let mut pending = String::new();
         let mut pending_stream = Stream::Stdout;
         let mut batch_started: Option<Instant> = None;
+        // Since when a decoder holds part of a line back to tell its encoding.
+        let mut held_since: Option<Instant> = None;
         let mut status: Option<Exit> = None;
         let mut drain_deadline: Option<Instant> = None;
 
@@ -1154,6 +1177,7 @@ fn spawn_pump(
             let now = Instant::now();
             let wait = [
                 batch_started.map(|t| (t + BATCH_INTERVAL).saturating_duration_since(now)),
+                held_since.map(|t| (t + BATCH_INTERVAL).saturating_duration_since(now)),
                 drain_deadline.map(|t| t.saturating_duration_since(now)),
             ]
             .into_iter()
@@ -1170,14 +1194,8 @@ fn spawn_pump(
                         Stream::Stdout => (&mut out_dec, &mut out_notice),
                         Stream::Stderr => (&mut err_dec, &mut err_notice),
                     };
-                    match notice {
-                        Some(filter) => {
-                            dec.decode_into(&bytes, &mut decoded);
-                            filter.filter(&decoded, &mut pending);
-                            decoded.clear();
-                        }
-                        None => dec.decode_into(&bytes, &mut pending),
-                    }
+                    emit(|out| dec.decode_into(&bytes, out), notice, &mut decoded, &mut pending);
+                    held_since = if out_dec.holds() || err_dec.holds() { held_since.or(Some(now)) } else { None };
                     if !pending.is_empty() && batch_started.is_none() {
                         batch_started = Some(Instant::now());
                     }
@@ -1193,6 +1211,25 @@ fn spawn_pump(
                     if drain_deadline.is_some_and(|d| Instant::now() >= d) {
                         break;
                     }
+                    // Nothing more came: show a held prompt.
+                    if held_since.is_some_and(|t| t.elapsed() >= BATCH_INTERVAL) {
+                        held_since = None;
+                        for (stream, dec, notice) in [
+                            (Stream::Stdout, &mut out_dec, &mut out_notice),
+                            (Stream::Stderr, &mut err_dec, &mut err_notice),
+                        ] {
+                            if dec.holds() {
+                                if stream != pending_stream {
+                                    flush(&mut pending, pending_stream, &mut batch_started);
+                                    pending_stream = stream;
+                                }
+                                emit(|out| dec.release(out), notice, &mut decoded, &mut pending);
+                            }
+                        }
+                        if !pending.is_empty() && batch_started.is_none() {
+                            batch_started = Some(Instant::now());
+                        }
+                    }
                     if batch_started.is_some_and(|t| t.elapsed() >= BATCH_INTERVAL) {
                         flush(&mut pending, pending_stream, &mut batch_started);
                     }

crates/ide-run/src/utf8.rs

@@ -136,6 +136,7 @@ mod tests {
 pub enum OutputDecoder {
     Utf8(Utf8Decoder),
     Other(Box<encoding_rs::Decoder>),
+    Mixed(Box<MixedDecoder>),
 }
 
 impl OutputDecoder {
@@ -147,10 +148,36 @@ impl OutputDecoder {
         }
     }
 
+    /// [`Self::for_label`] for output read from pipes. On Windows a UTF-8 console also decodes
+    /// what Windows' own programs write: the lines that are not UTF-8 in the system's console
+    /// code page (`ping`, `dir`, `cmd`'s messages), whatever the system's language, and UTF-16
+    /// (`wsl.exe`, `cmd /u`).
+    pub fn for_pipes(label: Option<&str>) -> Self {
+        match Self::for_label(label) {
+            Self::Utf8(_) if cfg!(windows) => Self::Mixed(Box::new(MixedDecoder::new(
+                ide_core::output_encoding::console_code_page().and_then(NativeDecoder::for_code_page),
+            ))),
+            other => other,
+        }
+    }
+
     pub fn decode_into(&mut self, bytes: &[u8], out: &mut String) {
         match self {
             Self::Utf8(d) => d.decode_into(bytes, out),
             Self::Other(d) => decode_with(d, bytes, out, false),
+            Self::Mixed(d) => d.decode_into(bytes, out),
+        }
+    }
+
+    /// Whether part of a line is held back until it shows its encoding.
+    pub fn holds(&self) -> bool {
+        matches!(self, Self::Mixed(d) if d.holds())
+    }
+
+    /// Decodes the held part of a line now (no more output came for a while).
+    pub fn release(&mut self, out: &mut String) {
+        if let Self::Mixed(d) = self {
+            d.release(out);
         }
     }
 
@@ -162,10 +189,218 @@ impl OutputDecoder {
                 decode_with(d, &[], &mut out, true);
                 out
             }
+            Self::Mixed(d) => d.finish(),
         }
     }
 }
 
+/// Decoder for a Windows code page: `encoding_rs`'s, or Windows' own for the single-byte
+/// pages `encoding_rs` lacks (the OEM pages 437, 850, 852…).
+pub enum NativeDecoder {
+    Encoding(Box<encoding_rs::Decoder>),
+    #[cfg(windows)]
+    SingleByte(u32),
+}
+
+impl NativeDecoder {
+    /// `None` for UTF-8 and for code pages neither can decode piece by piece.
+    pub fn for_code_page(cp: u32) -> Option<Self> {
+        if let Some(enc) = ide_core::output_encoding::encoding_for_code_page(cp) {
+            return (enc != encoding_rs::UTF_8)
+                .then(|| Self::Encoding(Box::new(enc.new_decoder_without_bom_handling())));
+        }
+        #[cfg(windows)]
+        if ide_core::output_encoding::is_single_byte_code_page(cp) {
+            return Some(Self::SingleByte(cp));
+        }
+        None
+    }
+
+    fn decode_into(&mut self, bytes: &[u8], out: &mut String, last: bool) {
+        match self {
+            Self::Encoding(d) => decode_with(d, bytes, out, last),
+            #[cfg(windows)]
+            Self::SingleByte(cp) => out.push_str(&ide_core::output_encoding::decode_code_page(bytes, *cp)),
+        }
+    }
+}
+
+#[derive(Clone, Copy, PartialEq, Eq, Debug)]
+enum Line {
+    /// Only ASCII so far, which reads the same in both.
+    Open,
+    Utf8,
+    Native,
+}
+
+/// UTF-8, the system code page for the lines that are not UTF-8, and UTF-16: on pipes, cargo,
+/// git or node write UTF-8, Windows' own programs the console code page (GBK, Shift_JIS,
+/// EUC-KR, 866…) and a few of them (`wsl.exe`, `cmd /u`) UTF-16LE, even within one command.
+///
+/// Each line is decoded as UTF-8 or the code page (UTF-8 with replacement characters without
+/// one). The part of a line after its first non-ASCII byte is held until the line ends or
+/// turns out not to be UTF-8; [`Self::release`] decodes a held prompt when no more output comes.
+///
+/// A read with NUL bytes, which text in the others never has, is UTF-16LE (ASCII characters
+/// and line ends in it have them); UTF-16 goes on until one of its lines has ended and a read
+/// without NUL bytes comes.
+pub struct MixedDecoder {
+    utf8: Utf8Decoder,
+    native: Option<NativeDecoder>,
+    line: Line,
+    held: Vec<u8>,
+    utf16: Option<Utf16>,
+}
+
+impl MixedDecoder {
+    pub fn new(native: Option<NativeDecoder>) -> Self {
+        Self { utf8: Utf8Decoder::new(), native, line: Line::Open, held: Vec::new(), utf16: None }
+    }
+
+    pub fn decode_into(&mut self, bytes: &[u8], out: &mut String) {
+        if bytes.is_empty() {
+            return;
+        }
+        let nul = bytes.contains(&0);
+        match self.utf16.as_ref().map(|u| u.open || nul) {
+            Some(true) => {
+                if let Some(u) = &mut self.utf16 {
+                    u.decode(bytes, out);
+                }
+                return;
+            }
+            Some(false) => self.utf16 = None,
+            None if nul => {
+                self.end_line(out);
+                let mut u = Utf16::new();
+                u.decode(utf16_aligned(bytes), out);
+                self.utf16 = Some(u);
+                return;
+            }
+            None => {}
+        }
+        for piece in bytes.split_inclusive(|b| *b == b'\n') {
+            let ends = piece.last() == Some(&b'\n');
+            match self.line {
+                Line::Utf8 => self.utf8.decode_into(piece, out),
+                Line::Native => self.decode_native(piece, out),
+                Line::Open => {
+                    let mut rest = piece;
+                    if self.held.is_empty() {
+                        let ascii = piece.iter().take_while(|b| b.is_ascii()).count();
+                        out.push_str(std::str::from_utf8(&piece[..ascii]).unwrap_or_default());
+                        rest = &piece[ascii..];
+                    }
+                    self.held.extend_from_slice(rest);
+                    let decided = match std::str::from_utf8(&self.held) {
+                        Err(e) if e.error_len().is_some() => Some(Line::Native),
+                        Ok(_) if ends => Some(Line::Utf8),
+                        _ => None,
+                    };
+                    if let Some(line) = decided {
+                        self.line = line;
+                        self.flush_held(out);
+                    }
+                }
+            }
+            if ends {
+                self.line = Line::Open;
+            }
+        }
+    }
+
+    fn flush_held(&mut self, out: &mut String) {
+        let held = std::mem::take(&mut self.held);
+        match self.line {
+            Line::Native => self.decode_native(&held, out),
+            Line::Open | Line::Utf8 => self.utf8.decode_into(&held, out),
+        }
+    }
+
+    fn decode_native(&mut self, bytes: &[u8], out: &mut String) {
+        match &mut self.native {
+            Some(native) => native.decode_into(bytes, out, false),
+            None => self.utf8.decode_into(bytes, out),
+        }
+    }
+
+    /// Decodes the rest of the current line as it is.
+    fn end_line(&mut self, out: &mut String) {
+        if self.holds() {
+            self.line = if std::str::from_utf8(&self.held).is_ok() { Line::Utf8 } else { Line::Native };
+            self.flush_held(out);
+        }
+        out.push_str(&self.utf8.finish());
+        self.line = Line::Open;
+    }
+
+    pub fn holds(&self) -> bool {
+        !self.held.is_empty()
+    }
+
+    /// Decodes the held part of the line as UTF-8: held text has been UTF-8 so far.
+    pub fn release(&mut self, out: &mut String) {
+        if self.holds() {
+            self.line = Line::Utf8;
+            self.flush_held(out);
+        }
+    }
+
+    pub fn finish(&mut self) -> String {
+        let mut out = String::new();
+        if let Some(mut u) = self.utf16.take() {
+            decode_with(&mut u.decoder, &[], &mut out, true);
+        }
+        self.end_line(&mut out);
+        if let Some(native) = &mut self.native {
+            native.decode_into(&[], &mut out, true);
+        }
+        out
+    }
+}
+
+struct Utf16 {
+    decoder: encoding_rs::Decoder,
+    /// Inside a line or a code unit: the next read goes on in UTF-16 whatever it holds.
+    open: bool,
+    /// An odd number of bytes so far.
+    odd: bool,
+}
+
+impl Utf16 {
+    fn new() -> Self {
+        Self { decoder: encoding_rs::UTF_16LE.new_decoder_with_bom_removal(), open: false, odd: false }
+    }
+
+    fn decode(&mut self, bytes: &[u8], out: &mut String) {
+        let start = out.len();
+        decode_with(&mut self.decoder, bytes, out, false);
+        self.odd ^= bytes.len() % 2 == 1;
+        if self.odd {
+            self.open = true;
+        } else if out.len() > start {
+            self.open = !out.ends_with('\n');
+        }
+    }
+}
+
+/// `bytes` from the first byte of a UTF-16LE code unit. NUL bytes are mostly the high bytes of
+/// ASCII characters, at odd offsets from it; at even ones, the first byte is the high byte of a
+/// character whose low byte came before (and was shown as ASCII).
+fn utf16_aligned(bytes: &[u8]) -> &[u8] {
+    let (mut even, mut odd) = (0usize, 0usize);
+    for (i, b) in bytes.iter().enumerate() {
+        if *b == 0 {
+            if i % 2 == 0 {
+                even += 1;
+            } else {
+                odd += 1;
+            }
+        }
+    }
+    if even > odd { &bytes[1..] } else { bytes }
+}
+
 fn decode_with(d: &mut encoding_rs::Decoder, bytes: &[u8], out: &mut String, last: bool) {
     let mut src = bytes;
     loop {
@@ -180,7 +415,8 @@ fn decode_with(d: &mut encoding_rs::Decoder, bytes: &[u8], out: &mut String, las
 
 #[cfg(test)]
 mod encoding_tests {
-    use super::OutputDecoder;
+    use super::{MixedDecoder, NativeDecoder, OutputDecoder};
+    use ide_core::output_encoding::encoding_for_code_page;
 
     #[test]
     fn gbk_split_across_chunks() {
@@ -202,4 +438,157 @@ mod encoding_tests {
         assert_eq!(out, "héllo");
         assert!(matches!(d, OutputDecoder::Utf8(_)));
     }
+
+    fn mixed(cp: u32) -> MixedDecoder {
+        MixedDecoder::new(Some(NativeDecoder::for_code_page(cp).expect("code page")))
+    }
+
+    fn encode(cp: u32, text: &str) -> Vec<u8> {
+        let (bytes, _, unmappable) = encoding_for_code_page(cp).expect("code page").encode(text);
+        assert!(!unmappable, "{text} in {cp}");
+        bytes.into_owned()
+    }
+
+    /// Simplified and Traditional Chinese, Korean, Japanese, Cyrillic (OEM and ANSI), Western.
+    const SAMPLES: &[(u32, &str)] = &[
+        (936, "正在 Ping 127.0.0.1 具有 32 字节的数据:"),
+        (950, "系統找不到指定的路徑。"),
+        (949, "지정된 경로를 찾을 수 없습니다."),
+        (932, "指定されたパスが見つかりません。"),
+        (866, "Системе не удается найти указанный путь."),
+        (1251, "Системе не удается найти указанный путь."),
+        (1252, "Le chemin d'accès spécifié est introuvable."),
+    ];
+
+    #[test]
+    fn utf8_and_code_page_lines_mix_whatever_the_chunks() {
+        for &(cp, native) in SAMPLES {
+            let mut bytes = "   Compiling 编译 ü\n".as_bytes().to_vec();
+            bytes.extend(encode(cp, native));
+            bytes.extend_from_slice(b"\r\n");
+            bytes.extend_from_slice("ok ✓\n".as_bytes());
+            bytes.extend(encode(cp, native));
+            let expected = format!("   Compiling 编译 ü\n{native}\r\nok ✓\n{native}");
+            for split in 0..=bytes.len() {
+                let mut d = mixed(cp);
+                let mut out = String::new();
+                d.decode_into(&bytes[..split], &mut out);
+                d.decode_into(&bytes[split..], &mut out);
+                out.push_str(&d.finish());
+                assert_eq!(out, expected, "code page {cp}, split at {split}");
+            }
+        }
+    }
+
+    #[test]
+    fn byte_by_byte_code_page_output() {
+        for &(cp, native) in SAMPLES {
+            let bytes = [encode(cp, native), b"\n".to_vec()].concat();
+            let mut d = mixed(cp);
+            let mut out = String::new();
+            for b in &bytes {
+                d.decode_into(std::slice::from_ref(b), &mut out);
+            }
+            assert!(!d.holds());
+            assert_eq!(out, format!("{native}\n"), "code page {cp}");
+        }
+    }
+
+    #[test]
+    fn ascii_and_code_page_prompts_show_at_once_and_utf8_ones_on_release() {
+        let mut d = mixed(936);
+        let mut out = String::new();
+        d.decode_into(b"Password: ", &mut out);
+        assert_eq!(out, "Password: ");
+        assert!(!d.holds());
+
+        out.clear();
+        d.decode_into(&encode(936, "请按任意键继续. . ."), &mut out);
+        assert_eq!(out, "请按任意键继续. . .");
+        assert!(!d.holds());
+
+        let mut d = mixed(936);
+        out.clear();
+        d.decode_into("Continue? 继续 ".as_bytes(), &mut out);
+        assert_eq!(out, "Continue? ");
+        assert!(d.holds());
+        d.release(&mut out);
+        assert_eq!(out, "Continue? 继续 ");
+        d.decode_into("[y/N]\n".as_bytes(), &mut out);
+        assert_eq!(out, "Continue? 继续 [y/N]\n");
+    }
+
+    #[test]
+    fn a_released_line_split_inside_a_character_completes() {
+        let mut d = mixed(949);
+        let mut out = String::new();
+        let bytes = "é中".as_bytes();
+        d.decode_into(&bytes[..3], &mut out);
+        d.release(&mut out);
+        d.decode_into(&bytes[3..], &mut out);
+        out.push_str(&d.finish());
+        assert_eq!(out, "é中");
+    }
+
+    #[test]
+    fn utf8_code_page_has_no_mixed_decoder() {
+        assert!(NativeDecoder::for_code_page(65001).is_none());
+    }
+
+    fn utf16(text: &str) -> Vec<u8> {
+        text.encode_utf16().flat_map(u16::to_le_bytes).collect()
+    }
+
+    /// What `wsl.exe -l -v` writes, on a Chinese system.
+    const WSL: &str = "  NAME            STATE           VERSION\r\n* Ubuntu-22.04    Running         2\r\n\
+                       适用于 Linux 的 Windows 子系统: 默认\r\n";
+
+    #[test]
+    fn utf16_output_between_utf8_and_code_page_lines_whatever_the_chunks() {
+        let before = "   Compiling 编译\n".as_bytes();
+        let wsl = utf16(WSL);
+        let after = [encode(936, "系统找不到指定的路径。"), "\r\ndone ✓\n".as_bytes().to_vec()].concat();
+        let expected = format!("   Compiling 编译\n{WSL}系统找不到指定的路径。\r\ndone ✓\n");
+        for split in 0..=wsl.len() {
+            let mut d = mixed(936);
+            let mut out = String::new();
+            for chunk in [before, &wsl[..split], &wsl[split..], &after] {
+                d.decode_into(chunk, &mut out);
+            }
+            out.push_str(&d.finish());
+            assert_eq!(out, expected, "split at {split}");
+        }
+    }
+
+    #[test]
+    fn utf16_with_a_byte_order_mark_or_starting_with_cjk() {
+        let mut d = mixed(949);
+        let mut out = String::new();
+        d.decode_into(&[&[0xFF, 0xFE][..], &utf16("한국어 OK\r\n")].concat(), &mut out);
+        d.decode_into(&utf16("中文 OK\r\n"), &mut out);
+        out.push_str(&d.finish());
+        assert_eq!(out, "한국어 OK\r\n中文 OK\r\n");
+    }
+
+    #[test]
+    fn without_a_code_page_other_lines_are_lossy_utf8_and_utf16_still_reads() {
+        let mut d = MixedDecoder::new(None);
+        let mut out = String::new();
+        d.decode_into(b"caf\xe9\n", &mut out);
+        d.decode_into(&utf16("wsl 子系统\r\n"), &mut out);
+        d.decode_into("ok ✓\n".as_bytes(), &mut out);
+        out.push_str(&d.finish());
+        assert_eq!(out, "caf\u{FFFD}\nwsl 子系统\r\nok ✓\n");
+    }
+
+    #[cfg(windows)]
+    #[test]
+    fn oem_code_pages_without_an_encoding_rs_table_decode_through_windows() {
+        for cp in [437, 850, 852] {
+            let mut d = mixed(cp);
+            let mut out = String::new();
+            d.decode_into(b"caf\x82\r\n", &mut out);
+            assert_eq!(out, "caf\u{e9}\r\n", "code page {cp}");
+        }
+    }
 }

crates/ide-run/tests/windows_output.rs

@@ -0,0 +1,69 @@
+#![cfg(windows)]
+
+use ide_core::{IdeEvent, SharedSink};
+use ide_run::{OutputChunk, ProcessManager, RunConfig, StartOptions};
+use parking_lot::Mutex;
+use std::collections::BTreeMap;
+use std::sync::Arc;
+use std::sync::mpsc;
+use std::time::Duration;
+
+/// Stdout and stderr of a shell command line run on pipes in a UTF-8 console.
+fn run(command: &str) -> String {
+    let (tx, events) = mpsc::channel();
+    let tx = Mutex::new(tx);
+    let sink: SharedSink = Arc::new(move |e: IdeEvent| {
+        let _ = tx.lock().send(e);
+    });
+    let root = tempfile::tempdir().unwrap();
+    let config = RunConfig {
+        id: "t:out".into(),
+        name: "t:out".into(),
+        kind: "shell".into(),
+        command: command.into(),
+        args: Vec::new(),
+        cwd: None,
+        env: BTreeMap::new(),
+        detected: false,
+        is_test: false,
+        debug_adapter: None,
+        allow_parallel: false,
+        extras: Default::default(),
+    };
+    let chunks: Arc<Mutex<Vec<OutputChunk>>> = Arc::default();
+    let out = chunks.clone();
+    let pm = ProcessManager::new();
+    let info = pm
+        .start(root.path(), &config, &StartOptions::default(), sink, Box::new(move |c| out.lock().push(c)))
+        .expect("start");
+    loop {
+        match events.recv_timeout(Duration::from_secs(20)).expect("RunExited event") {
+            IdeEvent::RunExited { run, .. } if run == info.id => break,
+            _ => {}
+        }
+    }
+    chunks
+        .lock()
+        .iter()
+        .filter_map(|c| match c {
+            OutputChunk::Stdout { text } | OutputChunk::Stderr { text } => Some(text.as_str()),
+            _ => None,
+        })
+        .collect()
+}
+
+/// `cmd`'s own messages reach the pipe in the console code page (GBK, Shift_JIS, EUC-KR,
+/// 437…, by the system's language), and still read right in a UTF-8 console.
+#[test]
+fn native_messages_in_the_console_code_page_are_decoded() {
+    let text = run(r"dir C:\openidea-no-such-dir");
+    assert!(text.trim().lines().count() >= 2, "{text:?}");
+    assert!(!text.contains('\u{FFFD}'), "{text:?}");
+}
+
+/// `cmd /u` writes UTF-16LE, as `wsl.exe` does; it reads right whatever the system's language.
+#[test]
+fn utf16_output_is_decoded() {
+    let text = run("cmd /u /c echo 中文 한국어 OK");
+    assert_eq!(text, "中文 한국어 OK\r\n");
+}

crates/ide-tools/Cargo.toml

@@ -19,8 +19,6 @@ tar = "0.4"
 zip.workspace = true
 sha2 = "0.10"
 hex = "0.4"
-
-[dev-dependencies]
 tempfile.workspace = true
 
 [target.'cfg(unix)'.dev-dependencies]