Merge branch 'relprep/pr-772' into relprep/pr-614

Both sides rewrite the /files walk. Keep the fair rounds from #614 and carry
the two things #772 does to the walk onto them: both queues start at walkRoot,
and the search predicate reads a path relative to the listing while every
returned path stays relative to workingDir.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/live-worktree.ts

@@ -0,0 +1,99 @@
+/**
+ * @fileoverview Which linked git worktree a session's pane is in.
+ *
+ * Claude Code's worktree feature moves the running `claude` process into
+ * `<repo>/.claude/worktrees/<name>` part way through a session. `Session.workingDir` is the
+ * session's identity and stays on the main checkout, so the Files panel kept listing a tree the
+ * agent had left (#765). `Session.paneCwd` does follow: tmux reads the process cwd, measured with
+ * Claude Code 2.1.318 going into a worktree on EnterWorktree and back on ExitWorktree. It also
+ * follows every `cd` in a shell session, so it cannot be the panel's root by itself. This module
+ * answers the narrower question: is the pane inside a linked worktree, and which one.
+ *
+ * A linked worktree is recognised by its `.git` FILE (`gitdir: <repo>/.git/worktrees/<id>`) rather
+ * than by running `git worktree list`: this runs from the pane watcher whenever a directory
+ * changes, and a file read starts no process, no repository config and no filter.
+ *
+ * Only a folder strictly below `workingDir` is ever an answer: the file routes already serve
+ * everything under it, so following a pane there widens nothing, and a planted `.git` file can
+ * only move where the listing STARTS inside that same folder. A worktree outside it
+ * (`git worktree add ../feature`) stays unfollowed, since listing it would need a second
+ * confinement root.
+ *
+ * That answer is lexical and only as fresh as the last time the pane moved: a symlink can take the
+ * folder's place afterwards without moving the pane. So nothing here is a confinement decision.
+ * `GET /api/sessions/:id/files` resolves the folder on every request and walks it only while it
+ * really lies inside `workingDir` (`canWalkLiveWorktree()` in file-routes.ts), and the routes keep
+ * judging every path against `workingDir`.
+ *
+ * Probes are bounded (#516). The folder can sit on a mount that stopped answering, and an
+ * `unknown` answer stops the walk rather than being read as "no `.git` here".
+ *
+ * @module live-worktree
+ */
+
+import { promises as fs } from 'node:fs';
+import { basename, dirname, join } from 'node:path';
+import { probePathKind } from './utils/bounded-path-probe.js';
+
+/** A linked worktree a session's pane is in. */
+export interface LiveWorktree {
+  /** The worktree folder's name, for display. */
+  name: string;
+  /** Absolute path, spelled like the session's `workingDir`. */
+  path: string;
+}
+
+/** More than any real `.git` file. It is read only to recognise the first line. */
+const MAX_DOT_GIT_FILE_BYTES = 4096;
+
+/**
+ * Whether the text of a `.git` file names a linked worktree's git dir
+ * (`<common dir>/worktrees/<id>`), as opposed to a submodule's (`<common dir>/modules/<name>`).
+ * The path may be relative: `git worktree add --relative-paths` writes it that way.
+ */
+export function isLinkedWorktreeGitFile(text: string): boolean {
+  const gitDir = /^gitdir:[ \t]*(.+?)[ \t]*$/m.exec(text)?.[1];
+  if (!gitDir) return false;
+  const segments = gitDir.split('/').filter(Boolean);
+  return segments.length >= 2 && segments[segments.length - 2] === 'worktrees';
+}
+
+/** What `<dir>/.git` says: a linked worktree's root, a boundary the walk must stop at, or nothing. */
+async function classifyDotGit(dir: string): Promise<'worktree' | 'stop' | 'none'> {
+  const dotGit = join(dir, '.git');
+  const kind = await probePathKind(dotGit);
+  if (kind === 'absent') return 'none';
+  // A `.git` directory is a repository of its own, and `unknown` is never read as absent.
+  if (kind !== 'file') return 'stop';
+  let handle: fs.FileHandle | undefined;
+  try {
+    // lstat, so a `.git` that is a symlink or a FIFO is refused before anything opens it:
+    // opening a FIFO waits for a writer and would hold a threadpool worker for good.
+    if (!(await fs.lstat(dotGit)).isFile()) return 'stop';
+    handle = await fs.open(dotGit, 'r');
+    const { buffer, bytesRead } = await handle.read(Buffer.alloc(MAX_DOT_GIT_FILE_BYTES), 0, MAX_DOT_GIT_FILE_BYTES, 0);
+    return isLinkedWorktreeGitFile(buffer.toString('utf8', 0, bytesRead)) ? 'worktree' : 'stop';
+  } catch {
+    return 'stop';
+  } finally {
+    await handle?.close().catch(() => {});
+  }
+}
+
+/**
+ * The linked worktree strictly below `workingDir` that holds `cwd`, if any. Walks up from `cwd`
+ * and stops at `workingDir`, at a repository or submodule of its own, or at anything it cannot
+ * read. `workingDir` itself is never an answer: a session started in a worktree is already
+ * listing it. Never throws.
+ */
+export async function findLiveWorktree(workingDir: string, cwd: string | undefined): Promise<LiveWorktree | undefined> {
+  if (!cwd?.startsWith('/')) return undefined;
+  const root = workingDir.length > 1 ? workingDir.replace(/\/+$/, '') : workingDir;
+  const under = root === '/' ? '/' : `${root}/`;
+  for (let dir = cwd; dir !== root && dir.startsWith(under); dir = dirname(dir)) {
+    const found = await classifyDotGit(dir);
+    if (found === 'worktree') return { name: basename(dir), path: dir };
+    if (found === 'stop') return undefined;
+  }
+  return undefined;
+}

src/session.ts

@@ -73,6 +73,7 @@ import type { GitFetchStatus } from './git-fetch.js';
 import { resolveAndClaimOmpSessionId } from './utils/omp-session-resolver.js';
 import { claudeTranscriptExists } from './utils/claude-transcript.js';
 import { probePathKind } from './utils/bounded-path-probe.js';
+import type { LiveWorktree } from './live-worktree.js';
 import { PATH_PROBE_TIMEOUT_MS, WORKSPACE_REALPATH_RETRY_MS } from './config/path-probe.js';
 import { matchesPattern } from './config/cli-registry/patterns.js';
 import { probeDockerCliVersion } from './docker-hosts.js';
@@ -766,6 +767,8 @@ export class Session extends EventEmitter {
    * serialized by toState() but never restored by the constructor.
    */
   private _paneCwd: string | undefined;
+  /** See {@link liveWorktree}. */
+  private _liveWorktree: LiveWorktree | undefined;
   /**
    * `workingDir` with symlinks resolved, so a pane reading (tmux reads the
    * process cwd, always the resolved path) can be put back into `workingDir`'s
@@ -1576,6 +1579,23 @@ export class Session extends EventEmitter {
     return true;
   }
 
+  /**
+   * The linked git worktree inside `workingDir` that {@link paneCwd} is in, when there is one
+   * (`live-worktree.ts`). The Files panel lists it instead of the main checkout. Runtime-only and
+   * never a confinement root, like `paneCwd`: it is judged lexically when the pane moves, and the
+   * listing route re-checks the real folder on every request.
+   */
+  get liveWorktree(): LiveWorktree | undefined {
+    return this._liveWorktree;
+  }
+
+  /** Record the result of a worktree lookup. Returns whether it CHANGED, so the caller broadcasts only then. */
+  setLiveWorktree(next: LiveWorktree | undefined): boolean {
+    if (next?.path === this._liveWorktree?.path) return false;
+    this._liveWorktree = next;
+    return true;
+  }
+
   /** `workingDir` without a trailing separator (the root stays `/`). */
   private _workspaceSpelling(): string {
     return this.workingDir.length > 1 ? this.workingDir.replace(/\/+$/, '') : this.workingDir;
@@ -2300,6 +2320,7 @@ export class Session extends EventEmitter {
       status: this._status,
       workingDir: this.workingDir,
       paneCwd: this._paneCwd,
+      liveWorktree: this._liveWorktree,
       remote: this._remote,
       docker: this._docker,
       owner: this._owner,

src/types/session.ts

@@ -34,6 +34,7 @@
 import type { RespawnConfig } from './respawn.js';
 import type { AttachmentDetectedType } from './tools.js';
 import type { GitFetchStatus } from '../git-fetch.js';
+import type { LiveWorktree } from '../live-worktree.js';
 
 /** Status of a Claude session */
 export type SessionStatus = 'idle' | 'busy' | 'stopped' | 'error';
@@ -847,6 +848,16 @@ export interface SessionState {
    * routes like any other out-of-workspace path.
    */
   paneCwd?: string;
+  /**
+   * The linked git worktree inside `workingDir` that the pane is in NOW, when there is one:
+   * Claude Code's `.claude/worktrees/<name>`, or any other worktree of the repository under
+   * the session's folder. Derived from {@link paneCwd} by `live-worktree.ts`, so it is
+   * runtime-only and absent wherever `paneCwd` is, and absent for a worktree outside
+   * `workingDir`: the file routes never serve those. NOT a confinement root; the Files panel
+   * only starts its listing here, after `GET .../files` has checked that the real folder still
+   * lies inside `workingDir`, since a symlink can replace it without moving the pane.
+   */
+  liveWorktree?: LiveWorktree;
   /** Remote execution metadata, present when this session runs over SSH through local tmux */
   remote?: SessionRemote;
   /** Docker execution metadata, present when this session runs inside a container via local tmux + docker exec */

src/web/public/app.js

@@ -2458,6 +2458,8 @@ class CodemanApp {
     }
     // cliMouseTracking (Claude's fullscreen mode) ends a keyboard row hold.
     if (session.id === this.activeSessionId) this._reconcileKeyboardHold?.();
+    // The agent moved into or out of a git worktree while the Files panel is open (#765).
+    if (session.id === this.activeSessionId) this._followFileBrowserWorktree?.(session);
     // Update parentSessionName for any subagents belonging to this session
     // (fixes stale name display after session rename)
     this.updateSubagentParentNames(session.id);

src/web/public/i18n.js

@@ -1133,6 +1133,9 @@
     'Filter by date range': '按日期范围筛选',
     'Filter by session status': '按会话状态筛选',
     'Filter files...': '筛选文件…',
+    Worktree: '工作树',
+    'Session folder': '会话文件夹',
+    'Back to worktree': '返回工作树',
     'Any status': '任意状态',
     'Any time': '任意时间',
     'Last hour': '最近一小时',

src/web/public/index.html

@@ -617,6 +617,11 @@
           <button class="btn-icon-sm" onclick="app.closeFileBrowserPanel()" title="Close">&times;</button>
         </div>
       </div>
+      <div class="file-browser-root" id="fileBrowserRoot" hidden>
+        <span class="file-browser-root-label" id="fileBrowserRootLabel"></span>
+        <span class="file-browser-root-name" id="fileBrowserRootName" data-i18n-skip></span>
+        <button type="button" class="file-browser-root-switch" id="fileBrowserRootSwitch" onclick="app.toggleFileBrowserRoot()"></button>
+      </div>
       <div class="file-browser-search">
         <input type="text" id="fileBrowserSearch" placeholder="Filter files..." oninput="app.filterFileBrowser(this.value)">
       </div>

src/web/public/panels-ui.js

@@ -3282,6 +3282,8 @@ Object.assign(CodemanApp.prototype, {
         matches: [],
         deferredDirectoryTarget: null,
         filter: typeof this.fileBrowserFilter === 'string' ? this.fileBrowserFilter : '',
+        // The person asked for the session folder while the agent is in a worktree (#765).
+        sessionRootPinned: false,
       };
     }
     return this._fileBrowserState;
@@ -3304,6 +3306,7 @@ Object.assign(CodemanApp.prototype, {
     state.deferredDirectoryTarget = null;
     state.filter = '';
     state.view = 'normal';
+    state.sessionRootPinned = false;
     this.fileBrowserData = null;
     this.fileBrowserFilter = '';
     this.fileBrowserExpandedDirs?.clear?.();
@@ -3314,6 +3317,7 @@ Object.assign(CodemanApp.prototype, {
     this._syncFileBrowserExpandBtn();
     const expandBtn = this.$?.('fileBrowserExpandBtn');
     if (expandBtn) expandBtn.innerHTML = '\u229E';
+    this._renderFileBrowserRoot(null);
 
     const panel = this.$?.('fileBrowserPanel');
     const treeEl = this.$?.('fileBrowserTree');
@@ -3346,6 +3350,7 @@ Object.assign(CodemanApp.prototype, {
     state.deferredDirectoryTarget = null;
     state.filter = '';
     state.view = 'normal';
+    state.sessionRootPinned = false;
     this.fileBrowserData = null;
     this.fileBrowserFilter = '';
     this.fileBrowserExpandedDirs?.clear?.();
@@ -3356,6 +3361,7 @@ Object.assign(CodemanApp.prototype, {
     this._syncFileBrowserExpandBtn();
     const expandBtn = this.$?.('fileBrowserExpandBtn');
     if (expandBtn) expandBtn.innerHTML = '\u229E';
+    this._renderFileBrowserRoot(null);
     const treeEl = this.$?.('fileBrowserTree');
     if (treeEl) treeEl.innerHTML = '';
     const statusEl = this.$?.('fileBrowserStatus');
@@ -3448,6 +3454,60 @@ Object.assign(CodemanApp.prototype, {
     this._syncFileBrowserExpandBtn();
     this.renderFileBrowserTree(normalState.sessionId);
     this._renderFileBrowserNormalStatus(normalState.data, normalState.showHidden);
+    this._renderFileBrowserRoot(normalState.data);
+  },
+
+  // The strip under the panel header, present only while the session's pane is in a linked
+  // worktree (#765): it says which of the two folders is listed and switches between them.
+  // Everything here comes from GET .../files, so the strip describes the tree on screen rather
+  // than the session's state a moment later.
+  _renderFileBrowserRoot(data) {
+    const strip = this.$?.('fileBrowserRoot');
+    if (!strip) return;
+    const worktree = data?.worktree;
+    if (typeof worktree?.path !== 'string' || typeof worktree?.name !== 'string') {
+      strip.hidden = true;
+      return;
+    }
+    const inWorktree = data.root === worktree.path;
+    const label = this.$?.('fileBrowserRootLabel');
+    const name = this.$?.('fileBrowserRootName');
+    const button = this.$?.('fileBrowserRootSwitch');
+    if (label) label.textContent = inWorktree ? 'Worktree' : 'Session folder';
+    if (name) name.textContent = inWorktree ? worktree.name : '';
+    if (button) button.textContent = inWorktree ? 'Session folder' : 'Back to worktree';
+    strip.title = typeof data.root === 'string' ? data.root : '';
+    strip.hidden = false;
+  },
+
+  // The `root` parameter of a listing or search. The server ignores it while the pane is not in
+  // a worktree, so the panel always asks unless the person chose the session folder.
+  _fileBrowserRootParam() {
+    return this._ensureFileBrowserState().sessionRootPinned ? '' : '&root=live';
+  },
+
+  toggleFileBrowserRoot() {
+    const state = this._ensureFileBrowserState();
+    state.sessionRootPinned = !state.sessionRootPinned;
+    return this._reloadFileBrowserKeepingQuery();
+  },
+
+  // Called on every session update of the active session. Compares with what the listing on
+  // screen reported rather than with the previous update, so a load already in flight when the
+  // pane moved is corrected by the next update, and an answer that matches ends it: a listing
+  // always reports the session's worktree, whichever folder it walked, so this cannot loop.
+  _followFileBrowserWorktree(session) {
+    const state = this._fileBrowserState;
+    if (!state || state.ownerSessionId !== session.id) return;
+    if (this.$?.('fileBrowserPanel')?.classList.contains('visible') !== true) return;
+    const normal = state.normalState;
+    if (normal?.phase !== 'ready' || normal.sessionId !== session.id) return;
+    const live = session.liveWorktree?.path ?? null;
+    const listed = normal.data?.worktree?.path ?? null;
+    if (live === listed) return;
+    // The pin was about the worktree the agent has just left.
+    state.sessionRootPinned = false;
+    this._reloadFileBrowserKeepingQuery();
   },
 
   _validateFileBrowserTreeEnvelope(result) {
@@ -3552,14 +3612,20 @@ Object.assign(CodemanApp.prototype, {
   },
 
   async toggleFileBrowserHidden() {
-    const state = this._ensureFileBrowserState();
-    const rawInput = typeof state.filter === 'string' ? state.filter : '';
-    const query = rawInput.trim();
     this.fileBrowserShowHidden = !this.fileBrowserShowHidden;
     try {
       localStorage.setItem(FILE_BROWSER_SHOW_HIDDEN_KEY, this.fileBrowserShowHidden ? '1' : '0');
     } catch {}
     this._syncFileBrowserHiddenBtn();
+    return this._reloadFileBrowserKeepingQuery();
+  },
+
+  // Re-fetch the tree after something the server filters on changed (hidden files, the listing's
+  // root), then re-run the search in the box against the new tree.
+  async _reloadFileBrowserKeepingQuery() {
+    const state = this._ensureFileBrowserState();
+    const rawInput = typeof state.filter === 'string' ? state.filter : '';
+    const query = rawInput.trim();
 
     if (state.inFlight?.timer !== undefined && state.inFlight?.timer !== null) {
       clearTimeout(state.inFlight.timer);
@@ -3633,7 +3699,7 @@ Object.assign(CodemanApp.prototype, {
     const request = (async () => {
       try {
         const res = await fetch(
-          `/api/sessions/${encodeURIComponent(sessionId)}/files?depth=5&showHidden=${showHidden}`,
+          `/api/sessions/${encodeURIComponent(sessionId)}/files?depth=5&showHidden=${showHidden}${this._fileBrowserRootParam()}`,
         );
         if (!res.ok) throw new Error('Failed to load files');
         const result = await res.json();
@@ -3820,6 +3886,7 @@ Object.assign(CodemanApp.prototype, {
       showHidden: this.fileBrowserShowHidden === true,
       rawInput,
       query,
+      rootParam: this._fileBrowserRootParam(),
       timer: null,
     };
     state.view = 'search-pending';
@@ -3834,7 +3901,7 @@ Object.assign(CodemanApp.prototype, {
       request.timer = null;
       try {
         const res = await fetch(
-          `/api/sessions/${encodeURIComponent(ownerSessionId)}/files?depth=5&showHidden=${request.showHidden}&q=${encodeURIComponent(query)}`,
+          `/api/sessions/${encodeURIComponent(ownerSessionId)}/files?depth=5&showHidden=${request.showHidden}&q=${encodeURIComponent(query)}${request.rootParam}`,
         );
         if (!res.ok) throw new Error('Search failed');
         const result = await res.json();

src/web/public/styles.css

@@ -12207,6 +12207,45 @@ html:is([data-skin="paper-gray"], [data-skin="solarized-light"], [data-skin="cat
   background: var(--bg-hover);
 }
 
+.file-browser-root {
+  display: flex;
+  align-items: center;
+  gap: 0.4rem;
+  padding: 0.25rem 0.5rem;
+  border-bottom: 1px solid var(--border);
+  font-size: 0.7rem;
+  color: var(--text-dim);
+}
+
+.file-browser-root[hidden] {
+  display: none;
+}
+
+.file-browser-root-name {
+  flex: 1 1 auto;
+  min-width: 0;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+  color: var(--text);
+}
+
+.file-browser-root-switch {
+  flex: 0 0 auto;
+  padding: 0.1rem 0.4rem;
+  border: 1px solid var(--border);
+  border-radius: 4px;
+  background: transparent;
+  color: inherit;
+  font: inherit;
+  cursor: pointer;
+}
+
+.file-browser-root-switch:hover {
+  color: var(--text);
+  border-color: var(--text-dim);
+}
+
 .file-browser-search {
   padding: 0.4rem;
   border-bottom: 1px solid var(--border);

src/web/routes/file-routes.ts

@@ -782,6 +782,26 @@ export function isPathWithinRoot(root: string, candidate: string): boolean {
   return rel === '' || (!isAbsolute(rel) && rel !== '..' && !rel.startsWith(`..${sep}`));
 }
 
+/**
+ * Whether a `root=live` listing may start at a session's `liveWorktree` (#765). `findLiveWorktree()`
+ * judged that path lexically when the pane moved, and a symlink can take its place, or a parent's,
+ * without moving the pane. The probe and `readdir` both follow one, and the walk's `path`s only look
+ * relative to `workingDir`, so this is the request-time half of the rule, the same one
+ * `validateSessionFilePath()` applies to a file: resolved, the worktree must lie strictly inside the
+ * resolved `workingDir`. Only the CHECK uses the resolved paths: the walk keeps the session's spelling,
+ * or a workspace reached through a symlink would stop producing paths relative to `workingDir`.
+ * Probed first (#516); both realpaths then walk the components that probe has just answered for.
+ */
+async function canWalkLiveWorktree(workingDir: string, worktreePath: string): Promise<boolean> {
+  if ((await probePathKind(worktreePath, { pastCap: true })) !== 'directory') return false;
+  try {
+    const [realRoot, realWorktree] = await Promise.all([fs.realpath(workingDir), fs.realpath(worktreePath)]);
+    return realWorktree !== realRoot && isPathWithinRoot(realRoot, realWorktree);
+  } catch {
+    return false;
+  }
+}
+
 function findMatchingPickerRoot(roots: FilesystemBrowseRoot[], candidate: string): FilesystemBrowseRoot | undefined {
   return roots
     .filter((root) => isPathWithinRoot(root.path, candidate))
@@ -1595,12 +1615,27 @@ export function registerFileRoutes(app: FastifyInstance, ctx: SessionPort & Even
   // File tree listing
   app.get('/api/sessions/:id/files', async (req) => {
     const { id } = req.params as { id: string };
-    const { depth, showHidden, q } = req.query as { depth?: string; showHidden?: string; q?: string };
+    const { depth, showHidden, q, root } = req.query as {
+      depth?: string;
+      showHidden?: string;
+      q?: string;
+      root?: string;
+    };
     const session = findSessionOrFail(ctx, id, req);
 
     const maxDepth = Math.min(parseInt(depth || '5', 10), 10);
     const includeHidden = showHidden === 'true';
     const workingDir = session.workingDir;
+    // `root=live` starts the walk at the linked worktree the pane is in (#765), once that folder
+    // proves to be inside `workingDir` right now, and every `path` below stays relative to
+    // `workingDir`, so file-content, file-raw and the edit route need nothing new and judge these
+    // paths against the same root as any other. Only the search predicate reads a path relative
+    // to the listing, since that is the tree the person is looking at.
+    const liveWorktree = session.liveWorktree;
+    const walkRoot =
+      root === 'live' && liveWorktree && (await canWalkLiveWorktree(workingDir, liveWorktree.path))
+        ? liveWorktree.path
+        : workingDir;
     // null for an empty/whitespace query, which is what keeps the default
     // tree response byte-identical when no search is requested.
     const matcher = compileFileQuery(q ?? '');
@@ -1654,7 +1689,7 @@ export function registerFileRoutes(app: FastifyInstance, ctx: SessionPort & Even
         index: number;
       }
 
-      const queue: SearchDirectoryCursor[] = [{ dirPath: workingDir, depth: 1, index: 0 }];
+      const queue: SearchDirectoryCursor[] = [{ dirPath: walkRoot, depth: 1, index: 0 }];
       while (queue.length > 0 && totalFiles + totalDirectories < maxFiles && matches.length < maxMatches) {
         // Give each discovered directory a slice before returning to a large sibling.
         const directoriesInRound = queue.length;
@@ -1692,17 +1727,18 @@ export function registerFileRoutes(app: FastifyInstance, ctx: SessionPort & Even
 
             const fullPath = join(cursor.dirPath, entry.name);
             const relativePath = relative(workingDir, fullPath);
+            const listedPath = relative(walkRoot, fullPath);
 
             if (entry.isDirectory()) {
               totalDirectories++;
-              if (matcher(entry.name, relativePath)) {
+              if (matcher(entry.name, listedPath)) {
                 matches.push({ name: entry.name, path: relativePath, type: 'directory' });
               }
               // Queue siblings together so one large subtree cannot starve later branches.
               queue.push({ dirPath: fullPath, depth: cursor.depth + 1, index: 0 });
             } else {
               totalFiles++;
-              if (matcher(entry.name, relativePath)) {
+              if (matcher(entry.name, listedPath)) {
                 let size: number | undefined;
                 try {
                   size = (await fs.stat(fullPath)).size;
@@ -1728,7 +1764,8 @@ export function registerFileRoutes(app: FastifyInstance, ctx: SessionPort & Even
       return {
         success: true,
         data: {
-          root: workingDir,
+          root: walkRoot,
+          ...(liveWorktree && { worktree: liveWorktree }),
           tree: [],
           matches,
           totalFiles,
@@ -1750,7 +1787,7 @@ export function registerFileRoutes(app: FastifyInstance, ctx: SessionPort & Even
     }
 
     const tree: FileTreeNode[] = [];
-    const queue: TreeDirectoryCursor[] = [{ dirPath: workingDir, depth: 1, nodes: tree, index: 0 }];
+    const queue: TreeDirectoryCursor[] = [{ dirPath: walkRoot, depth: 1, nodes: tree, index: 0 }];
     while (queue.length > 0 && totalFiles + totalDirectories < maxFiles) {
       const directoriesInRound = queue.length;
       const nodesPerDirectory = Math.max(
@@ -1818,7 +1855,8 @@ export function registerFileRoutes(app: FastifyInstance, ctx: SessionPort & Even
     return {
       success: true,
       data: {
-        root: workingDir,
+        root: walkRoot,
+        ...(liveWorktree && { worktree: liveWorktree }),
         tree,
         totalFiles,
         totalDirectories,

src/web/server.ts

@@ -35,6 +35,7 @@ import fastifyWebsocket from '@fastify/websocket';
 import fastifyMultipart from '@fastify/multipart';
 import { pasteImageDirInUseByOtherSession, startPasteImageGc, uploadDirs } from './paste-image-gc.js';
 import { CLEAN_EXIT_CLOSE_REASON, shouldCloseCleanlyExitedSession } from '../pane-exit-sweep.js';
+import { findLiveWorktree } from '../live-worktree.js';
 import { join, dirname } from 'node:path';
 import { fileURLToPath } from 'node:url';
 import { existsSync, mkdirSync, readFileSync, chmodSync, statSync } from 'node:fs';
@@ -2967,6 +2968,7 @@ export class WebServer extends EventEmitter {
       // `undefined` here means an authoritative read listed no single directory
       // for the session (split into several panes, or gone from the socket).
       const paneCwdChanged = getPaneCurrentPath ? session.setPaneCwd(getPaneCurrentPath(muxName)) : false;
+      if (paneCwdChanged) void this.refreshLiveWorktree(session);
       if (session.setPaneExit(getPaneExit(muxName))) {
         this.persistSessionState(session);
       } else if (!paneCwdChanged) {
@@ -2977,6 +2979,18 @@ export class WebServer extends EventEmitter {
     this.closeCleanlyExitedSessions();
   }
 
+  /**
+   * Work out which linked worktree a session's pane moved into (#765). In the background, since
+   * it reads the folder, and only after the directory changed, so an idle pane costs nothing.
+   * A reading newer than the one this lookup started from owns the answer.
+   */
+  private async refreshLiveWorktree(session: Session): Promise<void> {
+    const cwd = session.paneCwd;
+    const worktree = await findLiveWorktree(session.workingDir, cwd);
+    if (session.paneCwd !== cwd) return;
+    if (session.setLiveWorktree(worktree)) this.broadcastSessionStateDebounced(session.id);
+  }
+
   /**
    * Close every session whose agent exited cleanly, through the same
    * `cleanupSession()` the X button uses (Ark0N/Codeman#446). A pinned session