From bfbbbf08ef35886c9ef99d58cc72ce66a5e66c48 Mon Sep 17 00:00:00 2001
From: Chris Scott <>
Date: Fri, 16 Oct 2026 20:36:56 +0000
Subject: [PATCH 1/2] fix(activity): surface worktree sessions in active work,
 the sidebar and repo badges

- Resolve sessions in repo worktrees to the owning repo in the activity list; show the worktree branch and open the Workspaces tab
- Look up worktrees only for unmatched sessions in the window or under an active root, and hold the loading state until it settles
- Show schedule-worktree sessions only while running or needing input
- Light repo badges for worktree sessions through one app-wide worktree lookup
- List worktree sessions under the expanded repo in the sidebar
- Subscribe the event stream to active session directories so worktree permissions and forms arrive
- Keep the worktree tab when navigating from the desktop Activity panel
- Remove the braille spinner's always-dim bottom row
---
 frontend/src/App.tsx                          |  41 ++--
 .../components/activity/ActivityList.test.tsx |  17 ++
 .../src/components/activity/ActivityList.tsx  |   2 +-
 .../navigation/DesktopSessionTree.test.tsx    |  18 +-
 .../navigation/RepoQuickSwitchSheet.test.tsx  |   3 +-
 .../components/navigation/RepoSessionNav.tsx  |  35 ++-
 .../navigation/ToolSidePanel.test.tsx         |  18 ++
 .../components/navigation/ToolSidePanel.tsx   |   3 +-
 .../navigation/sidebar-session-tree.test.ts   |  54 +++++
 .../navigation/sidebar-session-tree.ts        |  37 ++-
 .../components/ui/activity-spinner.test.tsx   |  10 +-
 .../src/components/ui/activity-spinner.tsx    |   8 +-
 frontend/src/contexts/EventContext.test.tsx   |  39 +++
 frontend/src/contexts/EventContext.tsx        |  30 ++-
 .../contexts/RepoWorktreesContext.test.tsx    | 119 ++++++++++
 .../src/contexts/RepoWorktreesContext.tsx     |  58 +++++
 frontend/src/hooks/useActiveWork.test.tsx     |  66 +++++-
 frontend/src/hooks/useActiveWork.ts           |  42 ++--
 frontend/src/hooks/useRepoWorktrees.ts        |  28 +++
 frontend/src/hooks/useSidebarRepoGroups.ts    |  23 +-
 frontend/src/lib/activeWork.test.ts           | 222 ++++++++++++++++++
 frontend/src/lib/activeWork.ts                | 130 +++++++++-
 frontend/src/lib/navigation.ts                |  10 +-
 23 files changed, 932 insertions(+), 81 deletions(-)
 create mode 100644 frontend/src/contexts/RepoWorktreesContext.test.tsx
 create mode 100644 frontend/src/contexts/RepoWorktreesContext.tsx
 create mode 100644 frontend/src/hooks/useRepoWorktrees.ts

diff --git a/frontend/src/App.tsx b/frontend/src/App.tsx
index ba389943a..8d1613fdc 100644
--- a/frontend/src/App.tsx
+++ b/frontend/src/App.tsx
@@ -26,6 +26,7 @@ import { ThemeProvider, useThemeMode } from './contexts/ThemeContext'
 import { AuthProvider } from './contexts/AuthContext'
 import { KeyboardShortcutsProvider } from './contexts/KeyboardShortcutsContext'
 import { EventProvider, usePermissions, useEventContext } from '@/contexts/EventContext'
+import { RepoWorktreesProvider } from '@/contexts/RepoWorktreesContext'
 import { SwipeNavigationProvider, useSwipeNavigation } from '@/contexts/SwipeNavigationContext'
 import { PermissionRequestDialog } from './components/session/PermissionRequestDialog'
 import { SSHHostKeyDialog } from './components/ssh/SSHHostKeyDialog'
@@ -208,26 +209,28 @@ function AppShell() {
     <ThemeProvider>
       <AuthProvider>
         <EventProvider>
-          <KeyboardShortcutsProvider>
-            <GlobalShortcuts />
-            <div className="flex h-dvh w-full min-w-0 flex-col">
-              <PwaUpdatePrompt />
-              <div ref={rootRef} className="flex flex-1 min-h-0 w-full min-w-0">
-                <DesktopSidebar />
-                <main className="flex-1 min-w-0 min-h-0 flex flex-col">
-                  <Outlet />
-                </main>
+          <RepoWorktreesProvider>
+            <KeyboardShortcutsProvider>
+              <GlobalShortcuts />
+              <div className="flex h-dvh w-full min-w-0 flex-col">
+                <PwaUpdatePrompt />
+                <div ref={rootRef} className="flex flex-1 min-h-0 w-full min-w-0">
+                  <DesktopSidebar />
+                  <main className="flex-1 min-w-0 min-h-0 flex flex-col">
+                    <Outlet />
+                  </main>
+                </div>
               </div>
-            </div>
-            <MobileTabBar />
-            <MobileSheetHost />
-            <PermissionDialogWrapper />
-            <SSHHostKeyDialogWrapper />
-            <SettingsDialog />
-            <HealthMonitor />
-            <VersionNotifier />
-            <ThemedToaster />
-          </KeyboardShortcutsProvider>
+              <MobileTabBar />
+              <MobileSheetHost />
+              <PermissionDialogWrapper />
+              <SSHHostKeyDialogWrapper />
+              <SettingsDialog />
+              <HealthMonitor />
+              <VersionNotifier />
+              <ThemedToaster />
+            </KeyboardShortcutsProvider>
+          </RepoWorktreesProvider>
         </EventProvider>
       </AuthProvider>
     </ThemeProvider>
diff --git a/frontend/src/components/activity/ActivityList.test.tsx b/frontend/src/components/activity/ActivityList.test.tsx
index 53dda0804..313525326 100644
--- a/frontend/src/components/activity/ActivityList.test.tsx
+++ b/frontend/src/components/activity/ActivityList.test.tsx
@@ -144,6 +144,23 @@ describe('ActivityList', () => {
     expect(onNavigate).toHaveBeenCalledWith(item)
   })
 
+  it('labels a worktree session with its worktree branch', () => {
+    setGroups({
+      recent: [
+        createItem({
+          state: 'recent',
+          session: createSession('c1', 'Worktree'),
+          repo: createRepo(3, 'Gamma'),
+          worktreeBranch: 'feature/wt',
+        }),
+      ],
+    })
+
+    renderList()
+
+    expect(screen.getByRole('button', { name: /Worktree/ })).toHaveTextContent('Gamma · feature/wt')
+  })
+
   it('marks the currently open session with aria-current', () => {
     setGroups({
       recent: [
diff --git a/frontend/src/components/activity/ActivityList.tsx b/frontend/src/components/activity/ActivityList.tsx
index 161e242fd..00654c78e 100644
--- a/frontend/src/components/activity/ActivityList.tsx
+++ b/frontend/src/components/activity/ActivityList.tsx
@@ -63,7 +63,7 @@ interface ActivityRowProps {
 }
 
 function ActivityRow({ item, isCurrent, onSelect }: ActivityRowProps) {
-  const branch = getRepoBranchLabel(item.repo)
+  const branch = item.worktreeBranch ?? getRepoBranchLabel(item.repo)
   const repoLine = branch
     ? `${getRepoDisplayName(item.repo)} · ${branch}`
     : getRepoDisplayName(item.repo)
diff --git a/frontend/src/components/navigation/DesktopSessionTree.test.tsx b/frontend/src/components/navigation/DesktopSessionTree.test.tsx
index f33332729..68797fe0d 100644
--- a/frontend/src/components/navigation/DesktopSessionTree.test.tsx
+++ b/frontend/src/components/navigation/DesktopSessionTree.test.tsx
@@ -25,6 +25,7 @@ type SessionPinFixture = { sessionId: string; directory: string; pinnedAt: numbe
 
 const {
   listReposMock,
+  getRepoSiblingsMock,
   sessionsData,
   sessionsHookCalls,
   createSessionCalls,
@@ -37,6 +38,7 @@ const {
   searchError,
 } = vi.hoisted(() => ({
   listReposMock: vi.fn(),
+  getRepoSiblingsMock: vi.fn(),
   sessionsData: [] as SessionFixture[],
   sessionsHookCalls: [] as SessionsHookCall[],
   createSessionCalls: [] as Array<{ directory?: string; vars?: unknown }>,
@@ -51,7 +53,7 @@ const {
 
 vi.mock('@/api/repos', async (importOriginal) => {
   const actual = await importOriginal<typeof import('@/api/repos')>()
-  return { ...actual, listRepos: listReposMock }
+  return { ...actual, listRepos: listReposMock, getRepoSiblings: getRepoSiblingsMock }
 })
 
 vi.mock('@/api/opencode', async (importOriginal) => {
@@ -156,6 +158,8 @@ describe('DesktopSessionTree', () => {
   beforeEach(() => {
     listReposMock.mockReset()
     listReposMock.mockResolvedValue([repoA, repoB, repoC])
+    getRepoSiblingsMock.mockReset()
+    getRepoSiblingsMock.mockResolvedValue([])
     sessionsData.splice(
       0,
       sessionsData.length,
@@ -197,6 +201,18 @@ describe('DesktopSessionTree', () => {
     expect(fetchedDirectories()).toEqual(new Set(['/repos/a']))
   })
 
+  it('shows a worktree session under its repo with the worktree branch tag', async () => {
+    getRepoSiblingsMock.mockResolvedValue([
+      { fullPath: '/repos/a/.worktrees/feat', currentBranch: 'feat/x', worktreeSource: 'git' },
+    ])
+    sessionsData.push(createSession('w1', '/repos/a/.worktrees/feat', Date.now() - 1000))
+
+    render(<DesktopSessionTree />, { wrapper: createWrapper(['/repos/1']) })
+
+    const row = await screen.findByRole('button', { name: /^Session w1/ })
+    expect(row).toHaveTextContent('feat/x')
+  })
+
   it('opens nothing outside a repo', async () => {
     render(<DesktopSessionTree />, { wrapper: createWrapper(['/']) })
 
diff --git a/frontend/src/components/navigation/RepoQuickSwitchSheet.test.tsx b/frontend/src/components/navigation/RepoQuickSwitchSheet.test.tsx
index beb8e825b..14641d520 100644
--- a/frontend/src/components/navigation/RepoQuickSwitchSheet.test.tsx
+++ b/frontend/src/components/navigation/RepoQuickSwitchSheet.test.tsx
@@ -3,7 +3,7 @@ import { beforeEach, describe, it, expect, vi } from 'vitest'
 import { MemoryRouter, Route, Routes, useLocation } from 'react-router-dom'
 import { QueryClient, QueryClientProvider } from '@tanstack/react-query'
 import { RepoQuickSwitchSheet } from './RepoQuickSwitchSheet'
-import { listRepos } from '@/api/repos'
+import { getRepoSiblings, listRepos } from '@/api/repos'
 import { useMobileTabBar } from '@/hooks/useMobileTabBar'
 import { ASSISTANT_REPO_ID } from '@opencode-manager/shared/utils'
 import type { ActiveWorkItem } from '@/lib/activeWork'
@@ -167,6 +167,7 @@ function MobileSheetHarness() {
 describe('RepoQuickSwitchSheet', () => {
   beforeEach(() => {
     vi.clearAllMocks()
+    vi.mocked(getRepoSiblings).mockResolvedValue([])
     sessionsData.splice(0, sessionsData.length)
     sessionsHookCalls.splice(0, sessionsHookCalls.length)
     permissionSessions.current.clear()
diff --git a/frontend/src/components/navigation/RepoSessionNav.tsx b/frontend/src/components/navigation/RepoSessionNav.tsx
index 7907995ce..d24c8d63e 100644
--- a/frontend/src/components/navigation/RepoSessionNav.tsx
+++ b/frontend/src/components/navigation/RepoSessionNav.tsx
@@ -5,7 +5,9 @@ import { SessionStatusIndicator } from '@/components/ui/session-status-indicator
 import { RepoActivityIndicator } from '@/components/activity/RepoActivityIndicator'
 import { useForms, usePermissions } from '@/contexts/EventContext'
 import { useCreateSession } from '@/hooks/useOpenCode'
+import { useRepoSiblings } from '@/hooks/useRepoSiblings'
 import { useSidebarRepoGroups } from '@/hooks/useSidebarRepoGroups'
+import { buildWorktreeActivity, type ActiveWorktree } from '@/lib/activeWork'
 import { cn, formatShortRelativeTime, getRepoBranchLabel, getRepoDisplayName } from '@/lib/utils'
 import { getRepoPath, getSessionPath } from '@/lib/navigation'
 import {
@@ -118,13 +120,14 @@ interface SessionNavRowProps {
 export function SessionNavRow({ item, isCurrent, onSelect, repoLabel }: SessionNavRowProps) {
   const { hasForSession: hasPermission } = usePermissions()
   const { hasForSession: hasForm } = useForms()
+  const branchLabel = item.worktreeBranch ?? item.branchLabel
 
   return (
     <button
       type="button"
       onClick={() => onSelect(item.path)}
       aria-current={isCurrent ? 'page' : undefined}
-      title={item.branchLabel ? `${item.repoLabel} · ${item.branchLabel}` : item.repoLabel}
+      title={branchLabel ? `${item.repoLabel} · ${branchLabel}` : item.repoLabel}
       className={cn(
         'flex h-9 w-full items-center gap-2 pl-4 pr-3.5 text-left text-[13.5px] text-foreground hover:bg-accent/50',
         isCurrent && 'bg-primary/25 font-semibold',
@@ -137,6 +140,11 @@ export function SessionNavRow({ item, isCurrent, onSelect, repoLabel }: SessionN
       {repoLabel && (
         <span className="max-w-24 shrink-0 truncate text-xs text-highlight">{repoLabel}</span>
       )}
+      {item.worktreeBranch && (
+        <span className="max-w-24 shrink-0 truncate font-mono text-[11px] text-primary">
+          {item.worktreeBranch}
+        </span>
+      )}
       <SessionStatusIndicator sessionID={item.session.id} size="sm" />
       {hasPermission(item.session.id) && (
         <Bell className="h-3 w-3 shrink-0 text-highlight" aria-label="Pending permission" />
@@ -186,9 +194,32 @@ interface RepoSessionListProps {
 }
 
 function RepoSessionList({ repo, onSelectSession }: RepoSessionListProps) {
+  const siblings = useRepoSiblings(repo.isWorktree ? undefined : repo.id)
+  const worktrees = useMemo(
+    () =>
+      repo.isWorktree
+        ? undefined
+        : buildWorktreeActivity([repo], [{ data: siblings.data }]).filter(
+            (worktree) => !worktree.isSchedule,
+          ),
+    [repo, siblings.data],
+  )
+
+  if (siblings.isLoading) return <SessionNavStatus>Loading sessions...</SessionNavStatus>
+
+  return <RepoSessionListItems repo={repo} worktrees={worktrees} onSelectSession={onSelectSession} />
+}
+
+interface RepoSessionListItemsProps {
+  repo: Repo
+  worktrees?: ActiveWorktree[]
+  onSelectSession: (path: string) => void
+}
+
+function RepoSessionListItems({ repo, worktrees, onSelectSession }: RepoSessionListItemsProps) {
   const location = useLocation()
   const repos = useMemo(() => [repo], [repo])
-  const { groups, isLoading, isError, hasMore } = useSidebarRepoGroups({ repos })
+  const { groups, isLoading, isError, hasMore } = useSidebarRepoGroups({ repos, worktrees })
   const items = groups[0]?.items ?? []
 
   if (isLoading) return <SessionNavStatus>Loading sessions...</SessionNavStatus>
diff --git a/frontend/src/components/navigation/ToolSidePanel.test.tsx b/frontend/src/components/navigation/ToolSidePanel.test.tsx
index 951beb263..1ff5144d2 100644
--- a/frontend/src/components/navigation/ToolSidePanel.test.tsx
+++ b/frontend/src/components/navigation/ToolSidePanel.test.tsx
@@ -355,6 +355,24 @@ describe('ToolSidePanel', () => {
     expect(search().get('panel')).toBe('activity')
   })
 
+  it('keeps a worktree session tab when navigating from the Activity panel', async () => {
+    const user = userEvent.setup()
+    setActivityGroups([
+      {
+        ...createActivityItem('wt', 'Worktree Session', 2, 'Beta'),
+        path: '/repos/2/sessions/wt?repoTab=workspaces',
+      },
+    ])
+    renderAt('')
+
+    await user.click(screen.getByRole('button', { name: 'Activity' }))
+    await user.click(await screen.findByRole('button', { name: /Worktree Session/ }))
+
+    await waitFor(() => expect(screen.getByTestId('pathname').textContent).toBe('/repos/2/sessions/wt'))
+    expect(search().get('repoTab')).toBe('workspaces')
+    expect(search().get('panel')).toBe('activity')
+  })
+
   it('shows an Activity count pill and extends the accessible name', () => {
     activityMocks.useActiveWorkCounts.mockReturnValue({ needsInput: 1, running: 2 })
     renderAt('')
diff --git a/frontend/src/components/navigation/ToolSidePanel.tsx b/frontend/src/components/navigation/ToolSidePanel.tsx
index 033009fcc..ed36232da 100644
--- a/frontend/src/components/navigation/ToolSidePanel.tsx
+++ b/frontend/src/components/navigation/ToolSidePanel.tsx
@@ -25,6 +25,7 @@ import { isPanelTool, type ToolPanelState, type PanelTool } from '@/hooks/useToo
 import { useOpenNavItem } from '@/hooks/useOpenNavItem'
 import { ActivityList } from '@/components/activity/ActivityList'
 import { ActivityCountPill } from '@/components/activity/ActivityCountPill'
+import { withQueryParam } from '@/lib/navigation'
 import { useActiveWorkCounts, useActivityWindowMinutes } from '@/hooks/useActiveWork'
 import { formatActivityWindow } from '@/lib/activeWork'
 import { Tooltip, TooltipContent, TooltipProvider, TooltipTrigger } from '@/components/ui/tooltip'
@@ -52,7 +53,7 @@ function ActivityPanelBody() {
     <div className="min-h-0 flex-1 overflow-y-auto">
       <ActivityList
         minutes={minutes}
-        onNavigate={(item) => navigate({ pathname: item.path, search: '?panel=activity' })}
+        onNavigate={(item) => navigate(withQueryParam(item.path, 'panel', 'activity'))}
       />
     </div>
   )
diff --git a/frontend/src/components/navigation/sidebar-session-tree.test.ts b/frontend/src/components/navigation/sidebar-session-tree.test.ts
index e154791b4..cf95e9e0c 100644
--- a/frontend/src/components/navigation/sidebar-session-tree.test.ts
+++ b/frontend/src/components/navigation/sidebar-session-tree.test.ts
@@ -191,6 +191,60 @@ describe('buildSidebarRepoGroups', () => {
     expect(item.path).toBe('/repos/3/sessions/w1')
   })
 
+  it('groups a session in a worktree of a repo under that repo with the worktree branch', () => {
+    const worktree = {
+      directory: '/repos/a/.worktrees/feat',
+      ownerRepo: repoA,
+      branch: 'feat/x',
+      isSchedule: false,
+    }
+    const sessions = [createSession('w1', atStartOfDay(2000), '/repos/a/.worktrees/feat')]
+
+    const groups = buildSidebarRepoGroups({
+      repos: [repoA],
+      sessions,
+      pinnedKeys: new Set(),
+      now: NOW,
+      worktrees: [worktree],
+    })
+
+    expect(groups).toHaveLength(1)
+    const item = groups[0].items[0]
+    expect(item.session.id).toBe('w1')
+    expect(item.repoId).toBe(1)
+    expect(item.worktreeBranch).toBe('feat/x')
+    expect(item.path).toBe('/repos/1/sessions/w1?repoTab=workspaces')
+  })
+
+  it('matches a worktree session directory with a trailing slash', () => {
+    const worktree = {
+      directory: '/repos/a/.worktrees/feat',
+      ownerRepo: repoA,
+      branch: 'feat/x',
+      isSchedule: false,
+    }
+    const sessions = [createSession('w1', atStartOfDay(2000), '/repos/a/.worktrees/feat/')]
+
+    const groups = buildSidebarRepoGroups({
+      repos: [repoA],
+      sessions,
+      pinnedKeys: new Set(),
+      now: NOW,
+      worktrees: [worktree],
+    })
+
+    expect(groups[0].items.map((item) => item.session.id)).toEqual(['w1'])
+    expect(groups[0].items[0].worktreeBranch).toBe('feat/x')
+  })
+
+  it('excludes a worktree session when no worktrees are provided', () => {
+    const sessions = [createSession('w1', atStartOfDay(2000), '/repos/a/.worktrees/feat')]
+
+    const groups = buildSidebarRepoGroups({ repos: [repoA], sessions, pinnedKeys: new Set(), now: NOW })
+
+    expect(groups[0].items).toEqual([])
+  })
+
   it('labels assistant sessions and links them in assistant mode', () => {
     const assistant = createRepo({ id: 0, fullPath: '/assistant', localPath: 'assistant' })
     const sessions = [createSession('s1', atStartOfDay(1000), '/assistant')]
diff --git a/frontend/src/components/navigation/sidebar-session-tree.ts b/frontend/src/components/navigation/sidebar-session-tree.ts
index 05c77f7df..1d842a248 100644
--- a/frontend/src/components/navigation/sidebar-session-tree.ts
+++ b/frontend/src/components/navigation/sidebar-session-tree.ts
@@ -4,6 +4,7 @@ import { getRepoBranchLabel, getRepoDisplayName } from '@/lib/utils'
 import { getSessionKey } from '@/lib/sessionKey'
 import { getSessionPath, isAssistantPath, parseRepoRoute } from '@/lib/navigation'
 import { partitionSessions, selectRootSessions } from '@/components/session/session-partition'
+import type { ActiveWorktree } from '@/lib/activeWork'
 
 export const SIDEBAR_SESSIONS_PER_REPO = 10
 
@@ -30,6 +31,8 @@ export interface SidebarSessionItem {
   repoId: number
   repoLabel: string
   branchLabel: string | null
+  /** Branch of the worktree the session runs in, when it runs in a worktree of the group's repo. */
+  worktreeBranch?: string | null
   isWorktree: boolean
   isPinned: boolean
   path: string
@@ -88,16 +91,33 @@ export function buildSidebarRepoGroups(input: {
   sessions: Session[]
   pinnedKeys: ReadonlySet<string>
   now: number
+  worktrees?: ReadonlyArray<ActiveWorktree>
 }): SidebarRepoGroup[] {
-  const { repos, sessions, pinnedKeys, now } = input
+  const { repos, sessions, pinnedKeys, now, worktrees } = input
   const keyFn = getSessionKey
   const repoByDirectory = buildRepoByDirectory(repos)
 
-  const roots = selectRootSessions(sessions, {
-    directories: new Set(repos.map((repo) => repo.fullPath)),
-    keyFn,
-  }).flatMap((session) => {
+  const worktreeByDirectory = new Map<string, ActiveWorktree>()
+  for (const worktree of worktrees ?? []) {
+    worktreeByDirectory.set(worktree.directory, worktree)
+  }
+
+  const directories = new Set(repos.map((repo) => repo.fullPath))
+  for (const worktree of worktrees ?? []) {
+    directories.add(worktree.directory)
+  }
+  for (const session of sessions) {
+    const directory = normalizeDirectory(session.location.directory)
+    if (directory && worktreeByDirectory.has(directory)) {
+      directories.add(session.location.directory)
+    }
+  }
+
+  const roots = selectRootSessions(sessions, { directories, keyFn }).flatMap((session) => {
     if (session.time.archived) return []
+    const directory = normalizeDirectory(session.location.directory)
+    const worktree = directory ? worktreeByDirectory.get(directory) : undefined
+    if (worktree) return [{ session, repo: worktree.ownerRepo }]
     const repo = repoByDirectory.get(session.location.directory)
     if (!repo) return []
     return [{ session, repo }]
@@ -115,15 +135,20 @@ export function buildSidebarRepoGroups(input: {
 
   const createItem = (session: Session, repo: Repo): SidebarSessionItem => {
     const key = keyFn(session)
+    const directory = normalizeDirectory(session.location.directory)
+    const worktree = directory ? worktreeByDirectory.get(directory) : undefined
     return {
       key,
       session,
       repoId: repo.id,
       repoLabel: getRepoDisplayName(repo),
       branchLabel: getRepoBranchLabel(repo),
+      worktreeBranch: worktree ? worktree.branch : null,
       isWorktree: Boolean(repo.isWorktree),
       isPinned: pinnedKeys.has(key),
-      path: getSessionPath(repo.id, session.id),
+      path: worktree
+        ? getSessionPath(repo.id, session.id, { repoTab: 'workspaces' })
+        : getSessionPath(repo.id, session.id),
     }
   }
 
diff --git a/frontend/src/components/ui/activity-spinner.test.tsx b/frontend/src/components/ui/activity-spinner.test.tsx
index 9eac8fa4b..51fa73c05 100644
--- a/frontend/src/components/ui/activity-spinner.test.tsx
+++ b/frontend/src/components/ui/activity-spinner.test.tsx
@@ -16,11 +16,11 @@ const litIndexesFor = (frame: string) =>
 
 describe('brailleDots', () => {
   it('lights dots 1, 2 and 4 for the first frame', () => {
-    expect(brailleDots('⠋')).toEqual([true, true, false, true, false, false, false, false])
+    expect(brailleDots('⠋')).toEqual([true, true, false, true, false, false])
   })
 
   it('lights dots 1 through 4 for the last frame', () => {
-    expect(brailleDots('⠏')).toEqual([true, true, true, true, false, false, false, false])
+    expect(brailleDots('⠏')).toEqual([true, true, true, true, false, false])
   })
 })
 
@@ -30,10 +30,10 @@ describe('ActivitySpinner', () => {
     vi.useRealTimers()
   })
 
-  it('renders eight dots with the first frame lit and hidden from assistive technology', () => {
+  it('renders six dots with the first frame lit and hidden from assistive technology', () => {
     const { container } = render(<ActivitySpinner />)
 
-    expect(circles(container)).toHaveLength(8)
+    expect(circles(container)).toHaveLength(6)
     expect(litIndexes(container)).toEqual(litIndexesFor(SPINNER_FRAMES[0]))
     expect(container.querySelector('svg')).toHaveAttribute('aria-hidden', 'true')
   })
@@ -79,7 +79,7 @@ describe('ActivitySpinner', () => {
       r: Number(circle.getAttribute('r')),
     }))
 
-    expect(dots).toHaveLength(8)
+    expect(dots).toHaveLength(6)
 
     for (const dot of dots) {
       expect(dot.cx - dot.r).toBeGreaterThan(0)
diff --git a/frontend/src/components/ui/activity-spinner.tsx b/frontend/src/components/ui/activity-spinner.tsx
index bd0ea4ad7..456a1b174 100644
--- a/frontend/src/components/ui/activity-spinner.tsx
+++ b/frontend/src/components/ui/activity-spinner.tsx
@@ -13,19 +13,17 @@ const DOT_GRID: ReadonlyArray<readonly [number, number]> = [
   [1, 0],
   [1, 1],
   [1, 2],
-  [0, 3],
-  [1, 3],
 ]
 const COLUMN_X = [2.25, 6.75] as const
-const ROW_Y = [2.25, 6, 9.75, 13.5] as const
+const ROW_Y = [4.25, 8, 11.75] as const
 const DOT_RADIUS = 1.6
 const LIT_DOT_OPACITY = 1
 const UNLIT_DOT_OPACITY = 0.25
 
 /**
- * Decodes one braille frame into its eight dot positions, ordered by braille dot numbering:
+ * Decodes one braille frame into its six dot positions, ordered by braille dot numbering:
  * dot1, dot2 and dot3 are the left column top-to-bottom, dot4, dot5 and dot6 the right column
- * top-to-bottom, and dot7 and dot8 the bottom-left and bottom-right cells.
+ * top-to-bottom.
  */
 export function brailleDots(frame: string): boolean[] {
   const bits = (frame.codePointAt(0) ?? BRAILLE_BASE) - BRAILLE_BASE
diff --git a/frontend/src/contexts/EventContext.test.tsx b/frontend/src/contexts/EventContext.test.tsx
index a83599c25..615076337 100644
--- a/frontend/src/contexts/EventContext.test.tsx
+++ b/frontend/src/contexts/EventContext.test.tsx
@@ -2550,4 +2550,43 @@ describe('EventProvider permissions and forms', () => {
     expect(screen.getByTestId('permission-count').textContent).toBe('1')
     expect(screen.getByTestId('count').textContent).toBe('1')
   })
+
+  it('subscribes the directories of active sessions outside the repo directories', async () => {
+    mocks.listRepos.mockResolvedValue([{ id: 123, fullPath: '/repo' }])
+    const updateDirectories = vi.fn()
+    mocks.subscribeGlobalMonitor.mockReturnValue({
+      dispose: vi.fn(),
+      updateDirectories,
+      reconnect: vi.fn(),
+      reportVisibility: vi.fn(),
+    })
+
+    render(<Harness />, { wrapper: createWrapper() })
+
+    await waitFor(() => {
+      expect(updateDirectories).toHaveBeenCalledWith(['/repo'])
+    })
+
+    act(() => {
+      useSessionStatus.getState().setSessionDirectory('session-worktree', '/repo/.worktrees/feature')
+      useSessionStatus.getState().setStatus('session-worktree', { type: 'busy' })
+    })
+
+    await waitFor(() => {
+      expect(updateDirectories).toHaveBeenCalledWith(
+        expect.arrayContaining(['/repo', '/repo/.worktrees/feature']),
+      )
+    })
+
+    act(() => {
+      useSessionStatus.getState().setStatus('session-worktree', { type: 'idle' })
+    })
+
+    await waitFor(() => {
+      const calls = updateDirectories.mock.calls
+      const lastDirectories = calls[calls.length - 1][0] as string[]
+      expect(lastDirectories).toContain('/repo')
+      expect(lastDirectories).not.toContain('/repo/.worktrees/feature')
+    })
+  })
 })
diff --git a/frontend/src/contexts/EventContext.tsx b/frontend/src/contexts/EventContext.tsx
index 33dd55144..2a964a80d 100644
--- a/frontend/src/contexts/EventContext.tsx
+++ b/frontend/src/contexts/EventContext.tsx
@@ -236,6 +236,26 @@ async function settlePendingReply(
   }
 }
 
+/**
+ * Primitive key of every directory that hosts an active session: the recorded directory of each
+ * session whose status is not `idle`, plus each running shell's directory, sorted and de-duplicated.
+ * A string keeps the zustand subscription stable across store updates that do not change the set.
+ */
+export function selectActiveSessionDirectoriesKey(
+  state: Pick<ReturnType<typeof useSessionStatus.getState>, 'statuses' | 'directories' | 'runningShells'>,
+): string {
+  const directories = new Set<string>()
+  for (const [sessionID, status] of state.statuses.entries()) {
+    if (status.type === 'idle') continue
+    const directory = state.directories.get(sessionID)
+    if (directory) directories.add(directory)
+  }
+  for (const shell of state.runningShells.values()) {
+    if (shell.directory) directories.add(shell.directory)
+  }
+  return [...directories].sort().join('\n')
+}
+
 const EventContext = createContext<EventContextValue | null>(null)
 
 export function EventProvider({ children }: { children: React.ReactNode }) {
@@ -243,6 +263,7 @@ export function EventProvider({ children }: { children: React.ReactNode }) {
   const navigate = useNavigate()
   const location = useLocation()
   const sessionParents = useSessionStatus((state) => state.parents)
+  const activeSessionDirectoriesKey = useSessionStatus(selectActiveSessionDirectoriesKey)
 
   const [sshHostKeyRequest, setSSHHostKeyRequest] = useState<SSHHostKeyRequest | null>(null)
   const [sseHealth, setSseHealth] = useState<SSEHealthState>(() => {
@@ -858,9 +879,12 @@ export function EventProvider({ children }: { children: React.ReactNode }) {
 
   useEffect(() => {
     reposRef.current = repos
-    const directories = [...new Set((repos ?? []).map(r => r.fullPath))]
-    subscriptionRef.current?.updateDirectories(directories)
-  }, [repos])
+    const directories = new Set((repos ?? []).map(r => r.fullPath))
+    for (const directory of activeSessionDirectoriesKey.split('\n')) {
+      if (directory) directories.add(directory)
+    }
+    subscriptionRef.current?.updateDirectories([...directories])
+  }, [repos, activeSessionDirectoriesKey])
 
   useEffect(() => {
     if (!repos || repos.length === 0) return
diff --git a/frontend/src/contexts/RepoWorktreesContext.test.tsx b/frontend/src/contexts/RepoWorktreesContext.test.tsx
new file mode 100644
index 000000000..b2a84cb7b
--- /dev/null
+++ b/frontend/src/contexts/RepoWorktreesContext.test.tsx
@@ -0,0 +1,119 @@
+import { QueryClient, QueryClientProvider } from '@tanstack/react-query'
+import { act, render, screen, waitFor } from '@testing-library/react'
+import type { ReactNode } from 'react'
+import { beforeEach, describe, expect, it, vi } from 'vitest'
+import type { Repo } from '@/api/types'
+import { useSessionStatus } from '@/stores/sessionStatusStore'
+import { RepoWorktreesProvider, useRepoWorktreeList } from './RepoWorktreesContext'
+
+const mocks = vi.hoisted(() => ({
+  getRepoSiblings: vi.fn(),
+  useNavigableRepos: vi.fn(),
+}))
+
+vi.mock('@/api/repos', async (importOriginal) => {
+  const actual = await importOriginal<typeof import('@/api/repos')>()
+  return {
+    ...actual,
+    getRepoSiblings: mocks.getRepoSiblings,
+  }
+})
+
+vi.mock('@/hooks/useSidebarRepoGroups', () => ({
+  useNavigableRepos: mocks.useNavigableRepos,
+}))
+
+vi.mock('@/contexts/EventContext', () => ({
+  usePermissions: () => ({ pendingSessionIDs: [] }),
+  useForms: () => ({ pendingSessionIDs: [] }),
+}))
+
+const REPO_PATH = '/repo'
+const WORKTREE_PATH = '/repo/.worktrees/feature'
+
+const repo: Repo = {
+  id: 1,
+  fullPath: REPO_PATH,
+  localPath: REPO_PATH,
+  defaultBranch: 'main',
+  cloneStatus: 'ready',
+  clonedAt: 0,
+}
+
+const worktreeSibling = {
+  ...repo,
+  id: -1,
+  fullPath: WORKTREE_PATH,
+  localPath: 'feature',
+  sourcePath: WORKTREE_PATH,
+  currentBranch: 'feature',
+  worktreeSource: 'opencode' as const,
+}
+
+function WorktreeConsumer() {
+  const worktrees = useRepoWorktreeList()
+  return <div data-testid="worktrees">{worktrees.map((worktree) => worktree.directory).join(',')}</div>
+}
+
+const renderProvider = (queryClient: QueryClient) => {
+  const wrapper = ({ children }: { children: ReactNode }) => (
+    <QueryClientProvider client={queryClient}>{children}</QueryClientProvider>
+  )
+  return render(
+    <RepoWorktreesProvider>
+      <WorktreeConsumer />
+    </RepoWorktreesProvider>,
+    { wrapper },
+  )
+}
+
+const setActiveSession = (directory: string) => {
+  useSessionStatus.setState({
+    statuses: new Map([['session', { type: 'busy' as const }]]),
+    directories: new Map([['session', directory]]),
+  })
+}
+
+describe('RepoWorktreesProvider', () => {
+  beforeEach(() => {
+    mocks.getRepoSiblings.mockReset()
+    mocks.getRepoSiblings.mockResolvedValue([worktreeSibling])
+    mocks.useNavigableRepos.mockReset()
+    mocks.useNavigableRepos.mockReturnValue({ repos: [repo], isLoading: false, refetch: vi.fn() })
+    useSessionStatus.setState({
+      statuses: new Map(),
+      statusCache: new Map(),
+      statusRevisions: new Map(),
+      knownSessions: new Set(),
+      outcomes: new Map(),
+      parents: new Map(),
+      directories: new Map(),
+      runningShells: new Map(),
+      shellRevisions: new Map(),
+      shellRevision: 0,
+      revision: 0,
+    })
+  })
+
+  it('never fetches siblings when every active directory belongs to a repo', async () => {
+    setActiveSession(REPO_PATH)
+
+    renderProvider(new QueryClient({ defaultOptions: { queries: { retry: false } } }))
+
+    await act(async () => {
+      await Promise.resolve()
+    })
+
+    expect(mocks.getRepoSiblings).not.toHaveBeenCalled()
+    expect(screen.getByTestId('worktrees')).toHaveTextContent('')
+  })
+
+  it('fetches siblings and exposes the worktree when a busy session directory is unmatched', async () => {
+    setActiveSession(WORKTREE_PATH)
+
+    renderProvider(new QueryClient({ defaultOptions: { queries: { retry: false } } }))
+
+    await waitFor(() => expect(screen.getByTestId('worktrees')).toHaveTextContent(WORKTREE_PATH))
+    expect(mocks.getRepoSiblings).toHaveBeenCalledWith(1)
+  })
+})
diff --git a/frontend/src/contexts/RepoWorktreesContext.tsx b/frontend/src/contexts/RepoWorktreesContext.tsx
new file mode 100644
index 000000000..887e41872
--- /dev/null
+++ b/frontend/src/contexts/RepoWorktreesContext.tsx
@@ -0,0 +1,58 @@
+/* eslint-disable react-refresh/only-export-components */
+import { createContext, useContext, useMemo, type ReactNode } from 'react'
+import { useForms, usePermissions } from '@/contexts/EventContext'
+import { useNavigableRepos } from '@/hooks/useSidebarRepoGroups'
+import { useRepoWorktrees } from '@/hooks/useRepoWorktrees'
+import { useSessionStatus } from '@/stores/sessionStatusStore'
+import {
+  buildRepoActivityIndex,
+  hasUnmatchedActiveDirectory,
+  type ActiveWorktree,
+} from '@/lib/activeWork'
+
+const EMPTY_WORKTREES: ActiveWorktree[] = []
+
+const RepoWorktreesContext = createContext<ActiveWorktree[]>(EMPTY_WORKTREES)
+
+/** Pending permission and form session ids, merged once per snapshot into a referentially stable list. */
+export function usePendingInputSessionIDs(): string[] {
+  const pendingPermissionSessionIDs = usePermissions().pendingSessionIDs
+  const pendingFormSessionIDs = useForms().pendingSessionIDs
+
+  return useMemo(
+    () => [...pendingPermissionSessionIDs, ...pendingFormSessionIDs],
+    [pendingPermissionSessionIDs, pendingFormSessionIDs],
+  )
+}
+
+/**
+ * Discovers the repos' worktrees once for the whole app and shares them, so per-row repo badges can
+ * resolve a session running in a worktree to its owning repo without each row fetching. The worktree
+ * lookup only runs while some active session sits in a directory that matches no repo.
+ */
+export function RepoWorktreesProvider({ children }: { children: ReactNode }) {
+  const { repos } = useNavigableRepos()
+  const pendingInputSessionIDs = usePendingInputSessionIDs()
+
+  const enabled = useSessionStatus((state) =>
+    hasUnmatchedActiveDirectory(
+      buildRepoActivityIndex({
+        statuses: state.statuses,
+        parents: state.parents,
+        runningShells: state.runningShells,
+        directories: state.directories,
+        pendingInputSessionIDs,
+      }),
+      repos,
+    ),
+  )
+
+  const { worktrees } = useRepoWorktrees(repos, enabled)
+
+  return <RepoWorktreesContext.Provider value={worktrees}>{children}</RepoWorktreesContext.Provider>
+}
+
+/** The worktrees discovered for the app's repos, empty outside the provider. */
+export function useRepoWorktreeList(): ActiveWorktree[] {
+  return useContext(RepoWorktreesContext)
+}
diff --git a/frontend/src/hooks/useActiveWork.test.tsx b/frontend/src/hooks/useActiveWork.test.tsx
index c03ddf90f..e593af442 100644
--- a/frontend/src/hooks/useActiveWork.test.tsx
+++ b/frontend/src/hooks/useActiveWork.test.tsx
@@ -14,6 +14,7 @@ const WINDOW_MS = 60 * MS_PER_MINUTE
 const mocks = vi.hoisted(() => ({
   listSessionPage: vi.fn(),
   getSession: vi.fn(),
+  getRepoSiblings: vi.fn(),
   useNavigableRepos: vi.fn(),
   pendingSessionIDs: [] as string[],
 }))
@@ -27,6 +28,14 @@ vi.mock('@/api/opencode', async (importOriginal) => {
   }
 })
 
+vi.mock('@/api/repos', async (importOriginal) => {
+  const actual = await importOriginal<typeof import('@/api/repos')>()
+  return {
+    ...actual,
+    getRepoSiblings: mocks.getRepoSiblings,
+  }
+})
+
 vi.mock('@/hooks/useSidebarRepoGroups', () => ({
   useNavigableRepos: mocks.useNavigableRepos,
 }))
@@ -48,12 +57,17 @@ vi.mock('@/lib/toast', () => ({
   },
 }))
 
-const session = (id: string, updated: number, parentID?: string | null): SessionInfo => ({
+const session = (
+  id: string,
+  updated: number,
+  parentID?: string | null,
+  directory = REPO_PATH,
+): SessionInfo => ({
   id,
   projectID: 'proj_1',
   title: `Session ${id}`,
   time: { created: updated, updated },
-  location: { directory: REPO_PATH },
+  location: { directory },
   cost: 0,
   tokens: { input: 0, output: 0, reasoning: 0, cache: { read: 0, write: 0 } },
   ...(parentID === undefined ? {} : { parentID }),
@@ -83,6 +97,8 @@ describe('useActiveWork', () => {
   beforeEach(() => {
     mocks.listSessionPage.mockReset()
     mocks.getSession.mockReset()
+    mocks.getRepoSiblings.mockReset()
+    mocks.getRepoSiblings.mockResolvedValue([])
     mocks.useNavigableRepos.mockReset()
     mocks.useNavigableRepos.mockReturnValue({ repos: [repo], isLoading: false, refetch: vi.fn() })
     useSessionStatus.setState({
@@ -197,4 +213,50 @@ describe('useActiveWork', () => {
 
     expect(recentIDs(result.current.groups)).not.toContain('root')
   })
+
+  it('resolves a session in a worktree to its owning repo and opens the workspaces tab', async () => {
+    const now = Date.now()
+    mocks.listSessionPage.mockResolvedValue({
+      items: [session('wt', now - 500, undefined, '/repo/.worktrees/feature')],
+    })
+    mocks.getRepoSiblings.mockResolvedValue([
+      {
+        ...repo,
+        id: -1,
+        fullPath: '/repo/.worktrees/feature',
+        localPath: 'feature',
+        sourcePath: '/repo/.worktrees/feature',
+        currentBranch: 'feature',
+        worktreeSource: 'opencode',
+      },
+    ])
+
+    const { result } = renderHook(() => useActiveWork(WINDOW_MS), {
+      wrapper: createWrapper(createQueryClient()),
+    })
+
+    await waitFor(() => expect(recentIDs(result.current.groups)).toContain('wt'))
+
+    expect(result.current.groups.recent[0].repo.id).toBe(1)
+    expect(result.current.groups.recent[0].path).toBe('/repos/1/sessions/wt?repoTab=workspaces')
+  })
+
+  it('never fetches siblings for an orphan session updated outside the window', async () => {
+    const now = Date.now()
+    mocks.listSessionPage.mockResolvedValue({
+      items: [session('orphan', now - 2 * WINDOW_MS, undefined, '/outside/repo')],
+    })
+
+    const { result } = renderHook(() => useActiveWork(WINDOW_MS), {
+      wrapper: createWrapper(createQueryClient()),
+    })
+
+    await waitFor(() => expect(result.current.isLoading).toBe(false))
+
+    await act(async () => {
+      await Promise.resolve()
+    })
+
+    expect(mocks.getRepoSiblings).not.toHaveBeenCalled()
+  })
 })
diff --git a/frontend/src/hooks/useActiveWork.ts b/frontend/src/hooks/useActiveWork.ts
index 1daf1bf8e..edfc0f30e 100644
--- a/frontend/src/hooks/useActiveWork.ts
+++ b/frontend/src/hooks/useActiveWork.ts
@@ -3,23 +3,22 @@ import { useQueries, useQueryClient, type QueryClient } from '@tanstack/react-qu
 import type { SessionInfo } from '@opencode-manager/shared/opencode'
 import { sessionQueryOptions, useSessionsAcrossDirectories } from '@/hooks/useOpenCode'
 import { useNavigableRepos } from '@/hooks/useSidebarRepoGroups'
-import { useForms, usePermissions } from '@/contexts/EventContext'
+import { usePendingInputSessionIDs, useRepoWorktreeList } from '@/contexts/RepoWorktreesContext'
 import { useSessionStatus } from '@/stores/sessionStatusStore'
 import { useSettings } from '@/hooks/useSettings'
 import { DEFAULT_ACTIVITY_WINDOW_MINUTES } from '@/api/types/settings'
+import { useRepoWorktrees } from '@/hooks/useRepoWorktrees'
 import {
   MS_PER_MINUTE,
   buildActiveWork,
   buildRepoActivityIndex,
   collectActiveRoots,
+  needsWorktreeLookup,
   repoActivityFromIndex,
   rootSessionID,
   type ActiveWorkGroups,
 } from '@/lib/activeWork'
-import {
-  combineQuerySessions,
-  mergeExtraSessions,
-} from '@/components/navigation/sidebar-session-tree'
+import { combineQuerySessions, mergeExtraSessions } from '@/components/navigation/sidebar-session-tree'
 import type { Repo } from '@/api/types'
 
 const ACTIVE_WORK_SESSION_LIMIT = 50
@@ -33,17 +32,6 @@ export function useActivityWindowMinutes(): number {
   return preferences?.activityWindowMinutes ?? DEFAULT_ACTIVITY_WINDOW_MINUTES
 }
 
-/** Pending permission and form session ids, merged once per snapshot into a referentially stable list. */
-function usePendingInputSessionIDs(): string[] {
-  const pendingPermissionSessionIDs = usePermissions().pendingSessionIDs
-  const pendingFormSessionIDs = useForms().pendingSessionIDs
-
-  return useMemo(
-    () => [...pendingPermissionSessionIDs, ...pendingFormSessionIDs],
-    [pendingPermissionSessionIDs, pendingFormSessionIDs],
-  )
-}
-
 /**
  * Distinct active roots for a badge: needs-input roots and running roots that are not also
  * pending input. Reads only the session-status store and the pending queues, with no network.
@@ -72,6 +60,7 @@ export function useActiveWorkCounts(): { needsInput: number; running: number } {
  */
 export function useRepoActivityState(repo: Repo): 'needs-input' | 'running' | null {
   const pendingInputSessionIDs = usePendingInputSessionIDs()
+  const worktrees = useRepoWorktreeList()
 
   return useSessionStatus((state) =>
     repoActivityFromIndex(
@@ -83,6 +72,7 @@ export function useRepoActivityState(repo: Repo): 'needs-input' | 'running' | nu
         directories: state.directories,
         pendingInputSessionIDs,
       }),
+      worktrees,
     ),
   )
 }
@@ -256,6 +246,21 @@ export function useActiveWork(windowMs: number): {
     [sessions, fetchedSessions],
   )
 
+  const needsLookup = useMemo(
+    () =>
+      needsWorktreeLookup({
+        now,
+        windowMs,
+        repos,
+        sessions: mergedSessions,
+        parents: resolvedParents,
+        roots: resolvedRoots,
+      }),
+    [now, windowMs, repos, mergedSessions, resolvedParents, resolvedRoots],
+  )
+
+  const { worktrees, isLoading: isWorktreesLoading } = useRepoWorktrees(repos, needsLookup)
+
   const groups = useMemo(
     () =>
       buildActiveWork({
@@ -266,13 +271,14 @@ export function useActiveWork(windowMs: number): {
         parents: resolvedParents,
         roots: resolvedRoots,
         outcomes,
+        worktrees,
       }),
-    [now, windowMs, repos, mergedSessions, resolvedParents, resolvedRoots, outcomes],
+    [now, windowMs, repos, mergedSessions, resolvedParents, resolvedRoots, outcomes, worktrees],
   )
 
   return {
     groups,
-    isLoading: isReposLoading || isSessionsLoading,
+    isLoading: isReposLoading || isSessionsLoading || isWorktreesLoading,
     isError: isSessionsError,
   }
 }
diff --git a/frontend/src/hooks/useRepoWorktrees.ts b/frontend/src/hooks/useRepoWorktrees.ts
new file mode 100644
index 000000000..d3ee554cf
--- /dev/null
+++ b/frontend/src/hooks/useRepoWorktrees.ts
@@ -0,0 +1,28 @@
+import { useQueries } from '@tanstack/react-query'
+import { getRepoSiblings } from '@/api/repos'
+import { repoSiblingsQueryKey } from '@/hooks/useRepoSiblings'
+import { buildWorktreeActivity, type ActiveWorktree } from '@/lib/activeWork'
+import type { Repo } from '@/api/types'
+
+/**
+ * Discovers each repo's worktrees from its siblings while enabled, keyed by directory so a session
+ * running in a worktree resolves to the repo that owns it. Each query is skipped for repos without
+ * a positive id. `isLoading` is true while any enabled siblings query is still loading.
+ */
+export function useRepoWorktrees(
+  repos: Repo[],
+  enabled: boolean,
+): { worktrees: ActiveWorktree[]; isLoading: boolean } {
+  return useQueries({
+    queries: repos.map((repo) => ({
+      queryKey: repoSiblingsQueryKey(repo.id),
+      queryFn: () => getRepoSiblings(repo.id),
+      enabled: enabled && repo.id > 0,
+      staleTime: 30_000,
+    })),
+    combine: (results) => ({
+      worktrees: buildWorktreeActivity(repos, results),
+      isLoading: results.some((result) => result.isLoading),
+    }),
+  })
+}
diff --git a/frontend/src/hooks/useSidebarRepoGroups.ts b/frontend/src/hooks/useSidebarRepoGroups.ts
index 03c39ba6d..27fc5c068 100644
--- a/frontend/src/hooks/useSidebarRepoGroups.ts
+++ b/frontend/src/hooks/useSidebarRepoGroups.ts
@@ -5,6 +5,7 @@ import { sessionQueryOptions, useSessionsAcrossDirectories } from '@/hooks/useOp
 import { useSessionPins } from '@/hooks/useSessionPins'
 import { buildPinnedSessionKeys, buildSessionKey, getSessionKey } from '@/lib/sessionKey'
 import type { Repo } from '@/api/types'
+import type { ActiveWorktree } from '@/lib/activeWork'
 import {
   SIDEBAR_SESSIONS_PER_REPO,
   buildSidebarRepoGroups,
@@ -17,10 +18,17 @@ import {
 export function useSidebarRepoGroups(input: {
   repos: Repo[]
   search?: string
+  worktrees?: ReadonlyArray<ActiveWorktree>
 }): { groups: SidebarRepoGroup[]; isLoading: boolean; isError: boolean; hasMore: boolean } {
-  const { repos, search } = input
+  const { repos, search, worktrees } = input
 
-  const directories = useMemo(() => repos.map((repo) => repo.fullPath), [repos])
+  const directories = useMemo(
+    () => [
+      ...repos.map((repo) => repo.fullPath),
+      ...(worktrees ?? []).map((worktree) => worktree.directory),
+    ],
+    [repos, worktrees],
+  )
 
   const { data: sessions, isLoading, isError, hasNextPage } = useSessionsAcrossDirectories(directories, {
     search,
@@ -52,8 +60,15 @@ export function useSidebarRepoGroups(input: {
   )
 
   const groups = useMemo(
-    () => buildSidebarRepoGroups({ repos, sessions: mergedSessions, pinnedKeys, now: Date.now() }),
-    [repos, mergedSessions, pinnedKeys],
+    () =>
+      buildSidebarRepoGroups({
+        repos,
+        sessions: mergedSessions,
+        pinnedKeys,
+        now: Date.now(),
+        worktrees,
+      }),
+    [repos, mergedSessions, pinnedKeys, worktrees],
   )
 
   return { groups, isLoading, isError, hasMore: Boolean(hasNextPage) }
diff --git a/frontend/src/lib/activeWork.test.ts b/frontend/src/lib/activeWork.test.ts
index 73baa5abd..69493f633 100644
--- a/frontend/src/lib/activeWork.test.ts
+++ b/frontend/src/lib/activeWork.test.ts
@@ -2,14 +2,19 @@ import { describe, it, expect } from 'vitest'
 import type { Repo, Session } from '@/api/types'
 import type { ChildOutcome } from '@/lib/backgroundWork'
 import type { SessionStatusType } from '@/stores/sessionStatusStore'
+import type { RepoSibling, RepoWorktreeSource } from '@opencode-manager/shared/utils'
 import {
   buildActiveWork,
   buildRepoActivityIndex,
+  buildWorktreeActivity,
   collectActiveRoots,
   formatActivityEmptyMessage,
   formatActivityWindow,
+  hasUnmatchedActiveDirectory,
+  needsWorktreeLookup,
   repoActivityFromIndex,
   rootSessionID,
+  type ActiveWorktree,
 } from './activeWork'
 
 const NOW = 1_000_000_000_000
@@ -38,6 +43,14 @@ function createRepo(overrides: Partial<Repo> & { id: number; fullPath: string })
   }
 }
 
+function createWorktreeSibling(id: number, fullPath: string, branch: string, source: RepoWorktreeSource): RepoSibling {
+  return {
+    ...createRepo({ id, fullPath }),
+    currentBranch: branch,
+    worktreeSource: source,
+  }
+}
+
 function statuses(entries: Record<string, SessionStatusType>): Map<string, SessionStatusType> {
   return new Map(Object.entries(entries))
 }
@@ -254,6 +267,82 @@ describe('buildRepoActivityIndex and repoActivityFromIndex', () => {
   })
 })
 
+describe('repoActivityFromIndex with worktrees', () => {
+  const noShells = new Map<string, { sessionID: string; directory: string }>()
+  const main = createRepo({ id: 1, fullPath: '/repos/a' })
+  const other = createRepo({ id: 2, fullPath: '/repos/b' })
+
+  const indexFor = (entries: Record<string, string>, pending: string[] = []) =>
+    buildRepoActivityIndex({
+      statuses: statuses(Object.fromEntries(Object.keys(entries).map((id) => [id, { type: 'busy' as const }]))),
+      parents: new Map(),
+      runningShells: noShells,
+      directories: new Map(Object.entries(entries)),
+      pendingInputSessionIDs: pending,
+    })
+
+  it('returns running for a repo whose owned worktree directory is running', () => {
+    const index = indexFor({ session: '/repos/a/.worktrees/feature' })
+    const worktrees: ActiveWorktree[] = [
+      { directory: '/repos/a/.worktrees/feature', ownerRepo: main, branch: 'feature', isSchedule: false },
+    ]
+
+    expect(repoActivityFromIndex(main, index, worktrees)).toBe('running')
+  })
+
+  it('ignores worktrees owned by another repo', () => {
+    const index = indexFor({ session: '/repos/b/.worktrees/feature' })
+    const worktrees: ActiveWorktree[] = [
+      { directory: '/repos/b/.worktrees/feature', ownerRepo: other, branch: 'feature', isSchedule: false },
+    ]
+
+    expect(repoActivityFromIndex(main, index, worktrees)).toBeNull()
+  })
+
+  it('prefers needs-input from a worktree over running on the repo path', () => {
+    const index = buildRepoActivityIndex({
+      statuses: statuses({ own: { type: 'busy' }, wt: { type: 'busy' } }),
+      parents: new Map(),
+      runningShells: noShells,
+      directories: new Map([
+        ['own', '/repos/a'],
+        ['wt', '/repos/a/.worktrees/feature'],
+      ]),
+      pendingInputSessionIDs: ['wt'],
+    })
+    const worktrees: ActiveWorktree[] = [
+      { directory: '/repos/a/.worktrees/feature', ownerRepo: main, branch: 'feature', isSchedule: false },
+    ]
+
+    expect(repoActivityFromIndex(main, index, worktrees)).toBe('needs-input')
+  })
+})
+
+describe('hasUnmatchedActiveDirectory', () => {
+  const noShells = new Map<string, { sessionID: string; directory: string }>()
+
+  const indexFor = (directory: string) =>
+    buildRepoActivityIndex({
+      statuses: statuses({ session: { type: 'busy' } }),
+      parents: new Map(),
+      runningShells: noShells,
+      directories: new Map([['session', directory]]),
+      pendingInputSessionIDs: [],
+    })
+
+  it('is true when an index key matches no repo', () => {
+    expect(hasUnmatchedActiveDirectory(indexFor('/repos/other'), [repoA])).toBe(true)
+  })
+
+  it('is false when every indexed directory belongs to a repo', () => {
+    expect(hasUnmatchedActiveDirectory(indexFor('/repos/a'), [repoA])).toBe(false)
+  })
+
+  it('is false for an empty index', () => {
+    expect(hasUnmatchedActiveDirectory(new Map(), [repoA])).toBe(false)
+  })
+})
+
 describe('buildActiveWork', () => {
   it('puts a root with both a pending permission and a busy status in needs-input only, once', () => {
     const parents = new Map<string, string | null>()
@@ -388,4 +477,137 @@ describe('buildActiveWork', () => {
 
     expect(groups.recent.map((item) => item.session.id)).toEqual(['root'])
   })
+
+  it('resolves a session in a worktree to its owning repo and opens the workspaces tab', () => {
+    const main = createRepo({ id: 1, fullPath: '/repos/a' })
+    const sessions = [createSession('wt', NOW - 1000, '/repos/a/.worktrees/feature')]
+    const worktrees = [{ directory: '/repos/a/.worktrees/feature', ownerRepo: main, branch: 'feature', isSchedule: false }]
+
+    const groups = buildActiveWork({ now: NOW, windowMs: WINDOW_MS, repos: [main], sessions, parents: new Map(), roots: emptyRoots, outcomes: new Map(), worktrees })
+
+    expect(groups.recent).toHaveLength(1)
+    expect(groups.recent[0].repo.id).toBe(1)
+    expect(groups.recent[0].worktreeBranch).toBe('feature')
+    expect(groups.recent[0].path).toBe('/repos/1/sessions/wt?repoTab=workspaces')
+  })
+
+  it('drops a recent schedule worktree session but keeps it while its root is running', () => {
+    const main = createRepo({ id: 1, fullPath: '/repos/a' })
+    const worktrees = [
+      { directory: '/repos/a/.worktrees/nightly', ownerRepo: main, branch: 'nightly', isSchedule: true },
+    ]
+    const sessions = [createSession('sched', NOW - 1000, '/repos/a/.worktrees/nightly')]
+
+    const recentGroups = buildActiveWork({ now: NOW, windowMs: WINDOW_MS, repos: [main], sessions, parents: new Map(), roots: emptyRoots, outcomes: new Map(), worktrees })
+
+    expect(recentGroups.recent).toEqual([])
+
+    const runningGroups = buildActiveWork({ now: NOW, windowMs: WINDOW_MS, repos: [main], sessions, parents: new Map(), roots: { needsInput: new Set(), running: new Set(['sched']) }, outcomes: new Map(), worktrees })
+
+    expect(runningGroups.running.map((item) => item.session.id)).toEqual(['sched'])
+  })
+})
+
+describe('needsWorktreeLookup', () => {
+  const base = { now: NOW, windowMs: WINDOW_MS, repos: [repoA] }
+
+  it('returns true for an unmatched session updated inside the window', () => {
+    expect(
+      needsWorktreeLookup({
+        ...base,
+        sessions: [createSession('orphan', NOW - 1000, '/repos/other')],
+        parents: new Map(),
+        roots: emptyRoots,
+      }),
+    ).toBe(true)
+  })
+
+  it('returns false for an unmatched old idle session', () => {
+    expect(
+      needsWorktreeLookup({
+        ...base,
+        sessions: [createSession('orphan', NOW - WINDOW_MS - 1, '/repos/other')],
+        parents: new Map(),
+        roots: emptyRoots,
+      }),
+    ).toBe(false)
+  })
+
+  it('returns true for an unmatched old session whose root is running', () => {
+    const parents = new Map<string, string | null>([['orphan', 'root'], ['root', null]])
+
+    expect(
+      needsWorktreeLookup({
+        ...base,
+        sessions: [createSession('orphan', NOW - WINDOW_MS - 1, '/repos/other', 'root')],
+        parents,
+        roots: { needsInput: new Set(), running: new Set(['root']) },
+      }),
+    ).toBe(true)
+  })
+
+  it('returns false when every session matches a repo', () => {
+    expect(
+      needsWorktreeLookup({
+        ...base,
+        sessions: [createSession('matched', NOW - 1000, '/repos/a')],
+        parents: new Map(),
+        roots: emptyRoots,
+      }),
+    ).toBe(false)
+  })
+
+  it('returns false for an archived unmatched session', () => {
+    const archived = createSession('archived', NOW - 1000, '/repos/other')
+    archived.time.archived = NOW - 500
+
+    expect(
+      needsWorktreeLookup({
+        ...base,
+        sessions: [archived],
+        parents: new Map(),
+        roots: emptyRoots,
+      }),
+    ).toBe(false)
+  })
+})
+
+describe('buildWorktreeActivity', () => {
+  it('maps a worktree directory to its owning repo and branch', () => {
+    const main = createRepo({ id: 1, fullPath: '/repos/a' })
+    const worktree = createWorktreeSibling(-1, '/repos/a/.worktrees/feature', 'feature', 'opencode')
+
+    expect(buildWorktreeActivity([main], [{ data: [main, worktree] }])).toEqual([
+      { directory: '/repos/a/.worktrees/feature', ownerRepo: main, branch: 'feature', isSchedule: false },
+    ])
+  })
+
+  it('marks a schedule worktree as a schedule', () => {
+    const main = createRepo({ id: 1, fullPath: '/repos/a' })
+    const worktree = createWorktreeSibling(-1, '/repos/a/.worktrees/nightly', 'nightly', 'schedule')
+
+    expect(buildWorktreeActivity([main], [{ data: [worktree] }])).toEqual([
+      { directory: '/repos/a/.worktrees/nightly', ownerRepo: main, branch: 'nightly', isSchedule: true },
+    ])
+  })
+
+  it('prefers the non-worktree repo as owner and dedupes a worktree returned by several repos', () => {
+    const main = createRepo({ id: 1, fullPath: '/repos/a' })
+    const dbWorktree = createRepo({ id: 2, fullPath: '/repos/a-feature', isWorktree: true })
+    const worktree = createWorktreeSibling(-1, '/repos/a/.worktrees/feature', 'feature', 'git')
+
+    const entries = buildWorktreeActivity(
+      [dbWorktree, main],
+      [{ data: [worktree] }, { data: [worktree] }],
+    )
+
+    expect(entries).toHaveLength(1)
+    expect(entries[0].ownerRepo.id).toBe(1)
+  })
+
+  it('ignores siblings without a worktree source', () => {
+    const main = createRepo({ id: 1, fullPath: '/repos/a' })
+
+    expect(buildWorktreeActivity([main], [{ data: [main] }])).toEqual([])
+  })
 })
diff --git a/frontend/src/lib/activeWork.ts b/frontend/src/lib/activeWork.ts
index f9ccc2dd1..c8268405a 100644
--- a/frontend/src/lib/activeWork.ts
+++ b/frontend/src/lib/activeWork.ts
@@ -4,6 +4,7 @@ import type { SessionStatusType } from '@/stores/sessionStatusStore'
 import { getSessionKey } from '@/lib/sessionKey'
 import { getSessionPath } from '@/lib/navigation'
 import { findRepoForDirectory, normalizeDirectory } from '@/components/navigation/sidebar-session-tree'
+import { isWorktreeSibling, type RepoSibling } from '@opencode-manager/shared/utils'
 
 export const MS_PER_MINUTE = 60_000
 
@@ -34,6 +35,8 @@ export interface ActiveWorkItem {
   state: ActiveWorkState
   updatedAt: number
   outcome?: ChildOutcome
+  /** The worktree's branch when the session runs in a worktree of `repo`; null otherwise. */
+  worktreeBranch?: string | null
   path: string
 }
 
@@ -166,29 +169,126 @@ export function buildRepoActivityIndex(
   return index
 }
 
-/** The repo's activity from a prebuilt index, checking each of its paths. Needs-input outranks running. */
+/**
+ * The repo's activity from a prebuilt index, checking each of its own paths and the directories of
+ * the worktrees it owns. Needs-input outranks running.
+ */
 export function repoActivityFromIndex(
   repo: Repo,
   index: ReadonlyMap<string, 'needs-input' | 'running'>,
+  worktrees?: ReadonlyArray<ActiveWorktree>,
 ): 'needs-input' | 'running' | null {
   let running = false
 
-  for (const path of [repo.fullPath, repo.localPath, repo.sourcePath]) {
-    const normalized = normalizeDirectory(path)
-    if (!normalized) continue
+  const check = (directory?: string | null): boolean => {
+    const normalized = normalizeDirectory(directory)
+    if (!normalized) return false
     const state = index.get(normalized)
-    if (state === 'needs-input') return 'needs-input'
+    if (state === 'needs-input') return true
     if (state === 'running') running = true
+    return false
+  }
+
+  for (const path of [repo.fullPath, repo.localPath, repo.sourcePath]) {
+    if (check(path)) return 'needs-input'
+  }
+
+  for (const worktree of worktrees ?? []) {
+    if (worktree.ownerRepo.id !== repo.id) continue
+    if (check(worktree.directory)) return 'needs-input'
   }
 
   return running ? 'running' : null
 }
 
+/**
+ * True when some indexed active directory matches no repo, so a session is active in a directory
+ * outside the repo list (such as a worktree) and the worktree lookup is worth running.
+ */
+export function hasUnmatchedActiveDirectory(
+  index: ReadonlyMap<string, 'needs-input' | 'running'>,
+  repos: Repo[],
+): boolean {
+  for (const directory of index.keys()) {
+    if (!findRepoForDirectory(repos, directory)) return true
+  }
+  return false
+}
+
+/** A worktree directory and the repo that owns it, discovered from that repo's siblings. */
+export interface ActiveWorktree {
+  directory: string
+  ownerRepo: Repo
+  branch: string | null
+  /** True when the worktree belongs to a schedule rather than an interactive session. */
+  isSchedule: boolean
+}
+
+/**
+ * Collects the worktrees discovered through each repo's siblings, keyed by directory so a session
+ * running in a worktree resolves to its owning repo. A repo's siblings include the worktrees of its
+ * whole OpenCode project, so the same worktree can come back from several repos: the non-worktree
+ * repo wins so a worktree session opens on the main repo, and duplicates are dropped.
+ */
+export function buildWorktreeActivity(
+  repos: Repo[],
+  siblingResults: ReadonlyArray<{ data?: RepoSibling[] }>,
+): ActiveWorktree[] {
+  const ordered = repos
+    .map((repo, index) => ({ repo, siblings: siblingResults[index]?.data }))
+    .sort((a, b) => Number(Boolean(a.repo.isWorktree)) - Number(Boolean(b.repo.isWorktree)))
+
+  const worktrees: ActiveWorktree[] = []
+  const seen = new Set<string>()
+
+  for (const { repo, siblings } of ordered) {
+    for (const sibling of siblings ?? []) {
+      if (!isWorktreeSibling(sibling)) continue
+      const directory = normalizeDirectory(sibling.fullPath)
+      if (!directory || seen.has(directory)) continue
+      seen.add(directory)
+      worktrees.push({
+        directory,
+        ownerRepo: repo,
+        branch: sibling.currentBranch ?? sibling.branch ?? null,
+        isSchedule: sibling.worktreeSource === 'schedule',
+      })
+    }
+  }
+
+  return worktrees
+}
+
+/**
+ * Whether the worktree lookup is worth running: true when some non-archived session that matches no
+ * repo is either updated inside the window or has its root active (needs-input or running).
+ */
+export function needsWorktreeLookup(input: {
+  now: number
+  windowMs: number
+  repos: Repo[]
+  sessions: Session[]
+  parents: ReadonlyMap<string, string | null>
+  roots: { needsInput: Set<string>; running: Set<string> }
+}): boolean {
+  const { now, windowMs, repos, sessions, parents, roots } = input
+  const windowStart = now - windowMs
+
+  return sessions.some((session) => {
+    if (session.time.archived) return false
+    if (findRepoForDirectory(repos, session.location.directory)) return false
+    if (session.time.updated >= windowStart) return true
+    const rootID = rootSessionID(session.id, parents)
+    return roots.needsInput.has(rootID) || roots.running.has(rootID)
+  })
+}
+
 /**
  * Groups the given sessions into needs-input, running, and recent roots. A session appears in
  * exactly one group (needs-input over running over recent) and only when it resolves to a repo.
- * The input may mix roots and children; children never become items, but their latest update time
- * rolls up into the root's `updatedAt` and decides the recent window and ordering.
+ * A recent session in a schedule worktree is omitted so schedules only surface while they need
+ * attention. The input may mix roots and children; children never become items, but their latest
+ * update time rolls up into the root's `updatedAt` and decides the recent window and ordering.
  */
 export function buildActiveWork(input: {
   now: number
@@ -198,10 +298,16 @@ export function buildActiveWork(input: {
   parents: ReadonlyMap<string, string | null>
   roots: { needsInput: Set<string>; running: Set<string> }
   outcomes: ReadonlyMap<string, ChildOutcome>
+  worktrees?: ReadonlyArray<ActiveWorktree>
 }): ActiveWorkGroups {
-  const { now, windowMs, repos, sessions, parents, roots, outcomes } = input
+  const { now, windowMs, repos, sessions, parents, roots, outcomes, worktrees } = input
   const windowStart = now - windowMs
 
+  const worktreeByDirectory = new Map<string, ActiveWorktree>()
+  for (const worktree of worktrees ?? []) {
+    worktreeByDirectory.set(worktree.directory, worktree)
+  }
+
   const activityByRoot = new Map<string, number>()
   for (const session of sessions) {
     if (session.time.archived) continue
@@ -232,8 +338,11 @@ export function buildActiveWork(input: {
           : null
     if (!state) continue
 
-    const repo = findRepoForDirectory(repos, session.location.directory)
+    const directory = normalizeDirectory(session.location.directory)
+    const worktree = directory ? worktreeByDirectory.get(directory) : undefined
+    const repo = worktree?.ownerRepo ?? findRepoForDirectory(repos, session.location.directory)
     if (!repo) continue
+    if (worktree?.isSchedule && state === 'recent') continue
 
     seen.add(session.id)
     const item: ActiveWorkItem = {
@@ -243,7 +352,8 @@ export function buildActiveWork(input: {
       state,
       updatedAt,
       outcome: outcomes.get(session.id),
-      path: getSessionPath(repo.id, session.id),
+      worktreeBranch: worktree ? worktree.branch : null,
+      path: getSessionPath(repo.id, session.id, worktree ? { repoTab: 'workspaces' } : undefined),
     }
 
     if (state === 'needs-input') needsInput.push(item)
diff --git a/frontend/src/lib/navigation.ts b/frontend/src/lib/navigation.ts
index d46dc9e4a..6ed09ccbf 100644
--- a/frontend/src/lib/navigation.ts
+++ b/frontend/src/lib/navigation.ts
@@ -53,15 +53,19 @@ function isSafeInternalPath(path: string): boolean {
   return path.startsWith('/') && !path.startsWith('//');
 }
 
-export function getPathWithReturnTo(path: string, returnTo: string): string {
-  if (!isSafeInternalPath(returnTo)) return path;
+export function withQueryParam(path: string, key: string, value: string): string {
   const [base, query = ''] = path.split('?');
   const params = new URLSearchParams(query);
-  params.set('returnTo', returnTo);
+  params.set(key, value);
   const search = params.toString();
   return search ? `${base}?${search}` : base;
 }
 
+export function getPathWithReturnTo(path: string, returnTo: string): string {
+  if (!isSafeInternalPath(returnTo)) return path;
+  return withQueryParam(path, 'returnTo', returnTo);
+}
+
 export function getReturnToPath(search: string, fallback: string): string {
   const returnTo = new URLSearchParams(search).get('returnTo');
   return returnTo && isSafeInternalPath(returnTo) ? returnTo : fallback;

From 62c2eb8aed59dfe8f9a9e37b9cb6f1a56998a2ec Mon Sep 17 00:00:00 2001
From: Chris Scott <>
Date: Fri, 16 Oct 2026 20:50:35 +0000
Subject: [PATCH 2/2] fix(activity): report failed worktree lookups instead of
 showing partial session lists

---
 .../navigation/DesktopSessionTree.test.tsx         |  8 ++++++++
 .../src/components/navigation/RepoSessionNav.tsx   |  2 ++
 frontend/src/hooks/useActiveWork.test.tsx          | 14 ++++++++++++++
 frontend/src/hooks/useActiveWork.ts                |  8 ++++++--
 frontend/src/hooks/useRepoWorktrees.ts             |  7 +++++--
 5 files changed, 35 insertions(+), 4 deletions(-)

diff --git a/frontend/src/components/navigation/DesktopSessionTree.test.tsx b/frontend/src/components/navigation/DesktopSessionTree.test.tsx
index 68797fe0d..f028c5cbb 100644
--- a/frontend/src/components/navigation/DesktopSessionTree.test.tsx
+++ b/frontend/src/components/navigation/DesktopSessionTree.test.tsx
@@ -425,6 +425,14 @@ describe('DesktopSessionTree', () => {
     expect(await screen.findByText('Failed to load sessions')).toBeTruthy()
   })
 
+  it('shows the error state when the worktree siblings lookup fails', async () => {
+    getRepoSiblingsMock.mockRejectedValue(new Error('siblings failed'))
+
+    render(<DesktopSessionTree />, { wrapper: createWrapper(['/repos/1']) })
+
+    expect(await screen.findByText('Failed to load sessions')).toBeTruthy()
+  })
+
   it('creates a session in the repo full path', async () => {
     const user = userEvent.setup()
     render(<DesktopSessionTree />, { wrapper: createWrapper(['/']) })
diff --git a/frontend/src/components/navigation/RepoSessionNav.tsx b/frontend/src/components/navigation/RepoSessionNav.tsx
index d24c8d63e..926744f66 100644
--- a/frontend/src/components/navigation/RepoSessionNav.tsx
+++ b/frontend/src/components/navigation/RepoSessionNav.tsx
@@ -206,6 +206,8 @@ function RepoSessionList({ repo, onSelectSession }: RepoSessionListProps) {
   )
 
   if (siblings.isLoading) return <SessionNavStatus>Loading sessions...</SessionNavStatus>
+  if (siblings.isError && siblings.data === undefined)
+    return <SessionNavStatus>Failed to load sessions</SessionNavStatus>
 
   return <RepoSessionListItems repo={repo} worktrees={worktrees} onSelectSession={onSelectSession} />
 }
diff --git a/frontend/src/hooks/useActiveWork.test.tsx b/frontend/src/hooks/useActiveWork.test.tsx
index e593af442..13b62d2e9 100644
--- a/frontend/src/hooks/useActiveWork.test.tsx
+++ b/frontend/src/hooks/useActiveWork.test.tsx
@@ -241,6 +241,20 @@ describe('useActiveWork', () => {
     expect(result.current.groups.recent[0].path).toBe('/repos/1/sessions/wt?repoTab=workspaces')
   })
 
+  it('reports an error when the worktree siblings lookup fails with no cached data', async () => {
+    const now = Date.now()
+    mocks.listSessionPage.mockResolvedValue({
+      items: [session('wt', now - 500, undefined, '/repo/.worktrees/feature')],
+    })
+    mocks.getRepoSiblings.mockRejectedValue(new Error('siblings failed'))
+
+    const { result } = renderHook(() => useActiveWork(WINDOW_MS), {
+      wrapper: createWrapper(createQueryClient()),
+    })
+
+    await waitFor(() => expect(result.current.isError).toBe(true))
+  })
+
   it('never fetches siblings for an orphan session updated outside the window', async () => {
     const now = Date.now()
     mocks.listSessionPage.mockResolvedValue({
diff --git a/frontend/src/hooks/useActiveWork.ts b/frontend/src/hooks/useActiveWork.ts
index edfc0f30e..5be838ff2 100644
--- a/frontend/src/hooks/useActiveWork.ts
+++ b/frontend/src/hooks/useActiveWork.ts
@@ -259,7 +259,11 @@ export function useActiveWork(windowMs: number): {
     [now, windowMs, repos, mergedSessions, resolvedParents, resolvedRoots],
   )
 
-  const { worktrees, isLoading: isWorktreesLoading } = useRepoWorktrees(repos, needsLookup)
+  const {
+    worktrees,
+    isLoading: isWorktreesLoading,
+    isError: isWorktreesError,
+  } = useRepoWorktrees(repos, needsLookup)
 
   const groups = useMemo(
     () =>
@@ -279,6 +283,6 @@ export function useActiveWork(windowMs: number): {
   return {
     groups,
     isLoading: isReposLoading || isSessionsLoading || isWorktreesLoading,
-    isError: isSessionsError,
+    isError: isSessionsError || isWorktreesError,
   }
 }
diff --git a/frontend/src/hooks/useRepoWorktrees.ts b/frontend/src/hooks/useRepoWorktrees.ts
index d3ee554cf..d0d01bbcb 100644
--- a/frontend/src/hooks/useRepoWorktrees.ts
+++ b/frontend/src/hooks/useRepoWorktrees.ts
@@ -7,12 +7,14 @@ import type { Repo } from '@/api/types'
 /**
  * Discovers each repo's worktrees from its siblings while enabled, keyed by directory so a session
  * running in a worktree resolves to the repo that owns it. Each query is skipped for repos without
- * a positive id. `isLoading` is true while any enabled siblings query is still loading.
+ * a positive id. `isLoading` is true while any enabled siblings query is still loading. `isError`
+ * is true only when a siblings query has failed with no data, so a failed refetch that still has
+ * cached data is not an error.
  */
 export function useRepoWorktrees(
   repos: Repo[],
   enabled: boolean,
-): { worktrees: ActiveWorktree[]; isLoading: boolean } {
+): { worktrees: ActiveWorktree[]; isLoading: boolean; isError: boolean } {
   return useQueries({
     queries: repos.map((repo) => ({
       queryKey: repoSiblingsQueryKey(repo.id),
@@ -23,6 +25,7 @@ export function useRepoWorktrees(
     combine: (results) => ({
       worktrees: buildWorktreeActivity(repos, results),
       isLoading: results.some((result) => result.isLoading),
+      isError: results.some((result) => result.isError && result.data === undefined),
     }),
   })
 }