fix(desktop): avoid duplicate worktree startup status

Continuing an already materialized worktree session should behave like a normal existing session. The launch path now checks whether the session has already moved into its worktree before showing the startup bubble or passing worktree creation flags again.

Constraint: Existing session metadata can retain repository.worktree after the worktree transcript becomes the active session file
Rejected: Frontend-only suppression | the server could still launch the CLI with duplicate worktree creation flags
Confidence: high
Scope-risk: narrow
Tested: bun run check:server
Tested: bun test src/server/__tests__/conversations.test.ts -t worktree --timeout 30000
Tested: bun test src/server/__tests__/sessions.test.ts -t "newest duplicate session file" --timeout 30000
Not-tested: bun run verify still fails on unrelated desktop Settings.tsx and MessageList.tsx gates from the broader worktree

src/server/__tests__/conversations.test.ts

@@ -863,6 +863,31 @@ describe('WebSocket Chat Integration', () => {
     expect(statusVerbs).toContain('Creating worktree')
   })
 
+  it('does not emit worktree startup status for an already materialized worktree session', async () => {
+    const repoDir = await createCleanGitRepo()
+    const { sessionId } = await sessionService.createSession(repoDir, {
+      branch: 'feature/rail',
+      worktree: true,
+    })
+
+    const launchInfo = await sessionService.getSessionLaunchInfo(sessionId)
+    const worktreePath = launchInfo?.repository?.worktreePath
+    expect(worktreePath).toBeTruthy()
+    await fs.mkdir(worktreePath!, { recursive: true })
+    await sessionService.appendSessionMetadata(sessionId, {
+      workDir: worktreePath!,
+      repository: launchInfo!.repository,
+    })
+
+    const messages = await runTurn(sessionId, 'Continue in the existing worktree')
+    const statusVerbs = messages
+      .filter((msg) => msg.type === 'status')
+      .map((msg) => msg.verb)
+
+    expect(statusVerbs).toContain('Thinking')
+    expect(statusVerbs).not.toContain('Creating worktree')
+  })
+
   it('keeps the default startup status for current-worktree repository sessions', async () => {
     const repoDir = await createCleanGitRepo()
     const { sessionId } = await sessionService.createSession(repoDir, {

src/server/__tests__/sessions.test.ts

@@ -911,6 +911,26 @@ describe('SessionService', () => {
     expect(workDir).toBe('/tmp/latest-worktree')
   })
 
+  it('should prefer the newest duplicate session file when worktree metadata moves', async () => {
+    const sessionId = 'aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee'
+    const sourceFile = await writeSessionFile('-tmp-project', sessionId, [
+      makeSnapshotEntry(),
+      makeSessionMetaEntry('/tmp/project'),
+    ])
+    const worktreeFile = await writeSessionFile('-tmp-project--claude-worktrees-desktop-main-12345678', sessionId, [
+      makeSnapshotEntry(),
+      makeSessionMetaEntry('/tmp/project/.claude/worktrees/desktop-main-12345678'),
+    ])
+
+    const oldTime = new Date('2026-01-01T00:00:00.000Z')
+    const newTime = new Date('2026-01-01T00:00:01.000Z')
+    await fs.utimes(sourceFile, oldTime, oldTime)
+    await fs.utimes(worktreeFile, newTime, newTime)
+
+    const workDir = await service.getSessionWorkDir(sessionId)
+    expect(workDir).toBe('/tmp/project/.claude/worktrees/desktop-main-12345678')
+  })
+
   it('should recover CLI worktree state from transcript metadata', async () => {
     const sessionId = 'aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee'
     await writeSessionFile('-tmp-project--claude-worktrees-desktop-main-12345678', sessionId, [

src/server/services/conversationService.ts

@@ -13,7 +13,9 @@ import { ProviderService } from './providerService.js'
 import { sessionService } from './sessionService.js'
 import { diagnosticsService } from './diagnosticsService.js'
 import {
+  isMaterializedWorktreeLaunch,
   prepareSessionWorkspace,
+  shouldCreateWorktreeForSessionLaunch,
   type PreparedSessionWorkspace,
 } from './repositoryLaunchService.js'
 import {
@@ -146,6 +148,10 @@ export class ConversationService {
     const shouldResume = !!launchInfo && launchInfo.transcriptMessageCount > 0
     const shouldReplacePlaceholder =
       !!launchInfo && launchInfo.transcriptMessageCount === 0
+    const shouldCreateWorktree =
+      !!launchInfo && shouldCreateWorktreeForSessionLaunch(launchInfo)
+    const hasMaterializedWorktree =
+      !!launchInfo && isMaterializedWorktreeLaunch(launchInfo)
 
     if (this.deletedSessions.has(sessionId)) {
       throw new ConversationStartupError(
@@ -167,9 +173,9 @@ export class ConversationService {
 
     let launchWorkDir = workDir
     let launchRepository = launchInfo?.repository
-    if (!shouldResume && launchRepository?.worktree) {
+    if (shouldCreateWorktree && launchRepository?.worktree) {
       launchWorkDir = launchRepository.requestedWorkDir || launchRepository.repoRoot || workDir
-    } else if (!shouldResume && launchRepository) {
+    } else if (!shouldResume && launchRepository && !hasMaterializedWorktree) {
       const preparedWorkspace = await prepareSessionWorkspace(
         workDir,
         {
@@ -182,6 +188,13 @@ export class ConversationService {
       launchRepository = preparedWorkspace.repository
     }
 
+    if (!shouldCreateWorktree && launchRepository?.worktree) {
+      launchRepository = {
+        ...launchRepository,
+        worktree: false,
+      }
+    }
+
     if (!fs.existsSync(launchWorkDir) || !fs.statSync(launchWorkDir).isDirectory()) {
       throw new ConversationStartupError(
         `Working directory does not exist or is not a directory: ${launchWorkDir}`,

src/server/services/repositoryLaunchService.ts

@@ -82,6 +82,39 @@ export type PreparedSessionWorkspace = {
   }
 }
 
+export type RepositorySessionLaunchState = {
+  workDir: string
+  repository?: PreparedSessionWorkspace['repository']
+  worktreeSession?: { worktreePath?: string | null } | null
+  transcriptMessageCount: number
+}
+
+function samePath(left: string | null | undefined, right: string | null | undefined): boolean {
+  if (!left || !right) return false
+  return path.resolve(left) === path.resolve(right)
+}
+
+export function isMaterializedWorktreeLaunch(
+  launchInfo: RepositorySessionLaunchState,
+): boolean {
+  const worktreePath = launchInfo.repository?.worktreePath
+  return (
+    samePath(launchInfo.workDir, worktreePath) ||
+    samePath(launchInfo.workDir, launchInfo.worktreeSession?.worktreePath) ||
+    samePath(worktreePath, launchInfo.worktreeSession?.worktreePath)
+  )
+}
+
+export function shouldCreateWorktreeForSessionLaunch(
+  launchInfo: RepositorySessionLaunchState,
+): boolean {
+  return !!(
+    launchInfo.repository?.worktree &&
+    launchInfo.transcriptMessageCount === 0 &&
+    !isMaterializedWorktreeLaunch(launchInfo)
+  )
+}
+
 type GitResult = {
   stdout: string
   stderr: string

src/server/services/sessionService.ts

@@ -855,18 +855,20 @@ export class SessionService {
       return []
     }
 
-    const matches: Array<{ filePath: string; projectDir: string }> = []
+    const matches: Array<{ filePath: string; projectDir: string; mtimeMs: number }> = []
     for (const dir of projectDirs) {
       const filePath = path.join(projectsDir, dir, `${sessionId}.jsonl`)
       try {
-        await fs.access(filePath)
-        matches.push({ filePath, projectDir: dir })
+        const stat = await fs.stat(filePath)
+        matches.push({ filePath, projectDir: dir, mtimeMs: stat.mtimeMs })
       } catch {
         continue
       }
     }
 
     return matches
+      .sort((a, b) => b.mtimeMs - a.mtimeMs)
+      .map(({ filePath, projectDir }) => ({ filePath, projectDir }))
   }
 
   async findSessionFile(

src/server/ws/handler.ts

@@ -24,6 +24,7 @@ import {
   LOCAL_COMMAND_STDERR_TAG,
   LOCAL_COMMAND_STDOUT_TAG,
 } from '../../constants/xml.js'
+import { shouldCreateWorktreeForSessionLaunch } from '../services/repositoryLaunchService.js'
 
 const settingsService = new SettingsService()
 const providerService = new ProviderService()
@@ -80,7 +81,7 @@ async function sendRepositoryStartupStatus(
   const repository = launchInfo?.repository
   if (!repository) return
 
-  if (repository.worktree) {
+  if (shouldCreateWorktreeForSessionLaunch(launchInfo)) {
     sendMessage(ws, { type: 'status', state: 'thinking', verb: 'Creating worktree' })
   }
 }