Merge session title sanitation into main

Bring the detached worktree fix onto local main after verifying the title-generation regression path and local quality checks.

Constraint: The worktree commit was based on an older main commit, while local main already contained later chat scroll fixes.
Confidence: high
Scope-risk: moderate
Directive: Keep title sanitation shared across CLI, server, and desktop read paths.
Tested: bun run check:server
Tested: bun run check:desktop
Tested: bun run verify (7 passed, 1 failed on existing aggregate agent-utils coverage baseline)
Not-tested: live model title-generation smoke

desktop/src/lib/sessionTitle.test.ts

@@ -0,0 +1,14 @@
+import { describe, expect, it } from 'vitest'
+import { deriveSessionTitle } from './sessionTitle'
+
+describe('deriveSessionTitle', () => {
+  it('uses slash command metadata without showing raw XML tags', () => {
+    const raw = [
+      '<command-message>frontend-design</command-message>',
+      '<command-name>/frontend-design</command-name>',
+      '<command-args>@website 重新设计首页</command-args>',
+    ].join('\n')
+
+    expect(deriveSessionTitle(raw)).toBe('/frontend-design @website 重新设计首页')
+  })
+})

desktop/src/lib/sessionTitle.ts

@@ -6,8 +6,35 @@ const PLACEHOLDER_TITLES = new Set([
   'Untitled Session',
 ])
 
+const XML_TAG_BLOCK_PATTERN = /<([a-z][\w-]*)(?:\s[^>]*)?>[\s\S]*?<\/\1>\n?/g
+
+function decodeXmlText(text: string): string {
+  return text
+    .replace(/&lt;/g, '<')
+    .replace(/&gt;/g, '>')
+    .replace(/&quot;/g, '"')
+    .replace(/&#39;/g, "'")
+    .replace(/&amp;/g, '&')
+}
+
+function extractXmlTag(text: string, tag: string): string | undefined {
+  const match = text.match(new RegExp(`<${tag}(?:\\s[^>]*)?>([\\s\\S]*?)<\\/${tag}>`, 'i'))
+  const value = match?.[1]?.trim()
+  return value ? decodeXmlText(value) : undefined
+}
+
+function cleanSessionTitleSource(raw: string): string {
+  const commandName = extractXmlTag(raw, 'command-name')
+  const commandArgs = extractXmlTag(raw, 'command-args')
+  if (commandName) {
+    return [commandName, commandArgs].filter(Boolean).join(' ').replace(/\s+/g, ' ').trim()
+  }
+
+  return raw.replace(XML_TAG_BLOCK_PATTERN, ' ').replace(/\s+/g, ' ').trim()
+}
+
 export function deriveSessionTitle(raw: string): string | null {
-  const clean = raw.replace(/<[^>]+>[^<]*<\/[^>]+>/g, '').trim()
+  const clean = cleanSessionTitleSource(raw)
   const firstSentence = /^(.*?[.!?\u3002\uff01\uff1f])\s/.exec(clean)?.[1] ?? clean
   const flat = firstSentence.replace(/\s+/g, ' ').trim()
   if (!flat) return null

src/server/__tests__/sessions.test.ts

@@ -1304,6 +1304,41 @@ describe('SessionService', () => {
     expect(detail!.title).toBe('This is my first real question')
   })
 
+  it('should derive a clean title from slash command breadcrumb metadata', async () => {
+    const sessionId = 'aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee'
+    await writeSessionFile('-tmp-project', sessionId, [
+      makeSnapshotEntry(),
+      makeUserEntry([
+        '<command-message>frontend-design</command-message>',
+        '<command-name>/frontend-design</command-name>',
+        '<command-args>@website 重新设计首页</command-args>',
+      ].join('\n')),
+    ])
+
+    const detail = await service.getSession(sessionId)
+    expect(detail!.title).toBe('/frontend-design @website 重新设计首页')
+  })
+
+  it('should display stored AI titles without internal XML tags', async () => {
+    const sessionId = 'aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee'
+    await writeSessionFile('-tmp-project', sessionId, [
+      makeSnapshotEntry(),
+      makeUserEntry('fallback message'),
+      {
+        type: 'ai-title',
+        aiTitle: [
+          '<command-message>frontend-design</command-message>',
+          '<command-name>/frontend-design</command-name>',
+          '<command-args>@website</command-args>',
+        ].join(' '),
+        timestamp: '2026-01-01T00:02:00.000Z',
+      },
+    ])
+
+    const detail = await service.getSession(sessionId)
+    expect(detail!.title).toBe('/frontend-design @website')
+  })
+
   it('should truncate long titles to 80 chars', async () => {
     const sessionId = 'aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee'
     const longMessage = 'A'.repeat(120)

src/server/__tests__/title-service.test.ts

@@ -2,7 +2,7 @@ import { afterEach, beforeEach, describe, expect, test } from 'bun:test'
 import * as fs from 'fs/promises'
 import * as os from 'os'
 import * as path from 'path'
-import { generateTitle, parseGeneratedTitleText, saveAiTitle } from '../services/titleService.js'
+import { deriveTitle, generateTitle, parseGeneratedTitleText, saveAiTitle } from '../services/titleService.js'
 import { sessionService } from '../services/sessionService.js'
 
 describe('titleService', () => {
@@ -70,6 +70,71 @@ describe('titleService', () => {
     }
   })
 
+  test('derives slash-command titles from command metadata without raw XML tags', () => {
+    const raw = [
+      '<command-message>frontend-design</command-message>',
+      '<command-name>/frontend-design</command-name>',
+      '<command-args>@website 重新设计首页</command-args>',
+    ].join('\n')
+
+    expect(deriveTitle(raw)).toBe('/frontend-design @website 重新设计首页')
+  })
+
+  test('sends cleaned slash-command text to the title model', async () => {
+    let requestBody: {
+      messages?: Array<{ content?: string }>
+    } | null = null
+    const server = Bun.serve({
+      hostname: '127.0.0.1',
+      port: 0,
+      async fetch(req) {
+        requestBody = await req.json() as {
+          messages?: Array<{ content?: string }>
+        }
+        return Response.json({
+          content: [{ type: 'text', text: '{"title":"Redesign website"}' }],
+        })
+      },
+    })
+
+    try {
+      const providerId = 'title-clean-test'
+      await fs.mkdir(path.join(tmpDir, 'cc-haha'), { recursive: true })
+      await fs.writeFile(
+        path.join(tmpDir, 'cc-haha', 'providers.json'),
+        JSON.stringify({
+          activeId: providerId,
+          providers: [
+            {
+              id: providerId,
+              presetId: 'anthropic',
+              name: 'Anthropic',
+              apiKey: 'test-key',
+              baseUrl: `http://127.0.0.1:${server.port}/anthropic`,
+              apiFormat: 'anthropic',
+              models: {
+                main: 'claude-sonnet-4-7',
+                haiku: 'claude-haiku-4-5',
+                sonnet: 'claude-sonnet-4-7',
+                opus: 'claude-opus-4-7',
+              },
+            },
+          ],
+        }, null, 2),
+      )
+
+      await expect(generateTitle([
+        '<command-message>frontend-design</command-message>',
+        '<command-name>/frontend-design</command-name>',
+        '<command-args>@website 重新设计首页</command-args>',
+      ].join('\n'))).resolves.toBe('Redesign website')
+
+      expect(requestBody?.messages?.[0]?.content).toBe('/frontend-design @website 重新设计首页')
+    } finally {
+      server.stop(true)
+    }
+  })
+
   test('parses JSON title responses wrapped in markdown fences', () => {
     expect(parseGeneratedTitleText('```json\n{"title":"Write bash script"}\n```'))
       .toBe('Write bash script')
@@ -84,6 +149,14 @@ describe('titleService', () => {
     expect(parseGeneratedTitleText('```json\n{\\"title\\":')).toBeNull()
   })
 
+  test('normalizes XML-like title model output before persisting it', () => {
+    expect(parseGeneratedTitleText([
+      '<command-message>frontend-design</command-message>',
+      '<command-name>/frontend-design</command-name>',
+      '<command-args>@website</command-args>',
+    ].join(' '))).toBe('/frontend-design @website')
+  })
+
   test('does not persist automatic titles over a user custom title', async () => {
     const { sessionId } = await sessionService.createSession(os.tmpdir())
     await sessionService.renameSession(sessionId, 'My fixed name')

src/server/services/sessionService.ts

@@ -24,6 +24,7 @@ import {
   type CreateSessionRepositoryOptions,
   type PreparedSessionWorkspace,
 } from './repositoryLaunchService.js'
+import { cleanSessionTitleSource } from '../../utils/sessionTitleText.js'
 
 // ============================================================================
 // Types
@@ -734,7 +735,8 @@ export class SessionService {
     for (let i = entries.length - 1; i >= 0; i--) {
       const e = entries[i]!
       if (e.type === 'ai-title' && e.aiTitle) {
-        return e.aiTitle as string
+        const title = cleanSessionTitleSource(String(e.aiTitle))
+        if (title) return title
       }
     }
 
@@ -752,7 +754,8 @@ export class SessionService {
           if (textBlock) text = textBlock.text as string
         }
         if (text) {
-          return text.length > 80 ? text.slice(0, 80) + '...' : text
+          const title = cleanSessionTitleSource(text)
+          if (title) return title.length > 80 ? title.slice(0, 80) + '...' : title
         }
       }
     }

src/server/services/titleService.ts

@@ -11,6 +11,7 @@ import { SettingsService } from './settingsService.js'
 import { sessionService } from './sessionService.js'
 import { PROVIDER_PRESETS } from '../config/providerPresets.js'
 import { isEnvTruthy } from '../../utils/envUtils.js'
+import { cleanSessionTitleSource, hasSessionTitleMarkup } from '../../utils/sessionTitleText.js'
 
 const TITLE_MAX_LEN = 50
 
@@ -33,7 +34,7 @@ Bad (wrong case): {"title": "Fix Login Button On Mobile"}`
  * Returns first sentence, collapsed to single line, max 50 chars.
  */
 export function deriveTitle(raw: string): string | undefined {
-  const clean = raw.replace(/<[^>]+>[^<]*<\/[^>]+>/g, '').trim()
+  const clean = cleanSessionTitleSource(raw)
   const firstSentence = /^(.*?[.!?。！？])\s/.exec(clean)?.[1] ?? clean
   const flat = firstSentence.replace(/\s+/g, ' ').trim()
   if (!flat) return undefined
@@ -50,7 +51,7 @@ export async function generateTitle(
   conversationText: string,
   providerId?: string | null,
 ): Promise<string | null> {
-  const trimmed = conversationText.trim()
+  const trimmed = cleanSessionTitleSource(conversationText)
   if (!trimmed) return null
 
   try {
@@ -157,8 +158,13 @@ function parseTitleJson(candidate: string): string | null {
 }
 
 function normalizeTitle(title: string): string | null {
-  const clean = title.replace(/\s+/g, ' ').trim()
-  if (!clean || clean.length > 60 || looksLikeStructuredTitleFragment(clean)) return null
+  const clean = cleanSessionTitleSource(title)
+  if (
+    !clean ||
+    clean.length > 60 ||
+    looksLikeStructuredTitleFragment(clean) ||
+    hasSessionTitleMarkup(clean)
+  ) return null
   return clean
 }
 

src/utils/__tests__/sessionTitle.test.ts

@@ -0,0 +1,28 @@
+import { describe, expect, test } from 'bun:test'
+import { generateSessionTitle, normalizeGeneratedSessionTitle } from '../sessionTitle.js'
+
+describe('sessionTitle', () => {
+  test('normalizes command XML emitted by title generation', () => {
+    const raw = [
+      '<command-message>frontend-design</command-message>',
+      '<command-name>/frontend-design</command-name>',
+      '<command-args>@website redesign the homepage</command-args>',
+    ].join('\n')
+
+    expect(normalizeGeneratedSessionTitle(raw)).toBe('/frontend-design @website redesign the homepage')
+  })
+
+  test('rejects empty or oversized generated titles', () => {
+    expect(normalizeGeneratedSessionTitle('<ide_opened_file>src/app.ts</ide_opened_file>')).toBeNull()
+    expect(normalizeGeneratedSessionTitle('x'.repeat(81))).toBeNull()
+  })
+
+  test('skips title generation when internal XML metadata leaves no title source', async () => {
+    const title = await generateSessionTitle(
+      '<ide_opened_file>src/app.ts</ide_opened_file>',
+      AbortSignal.timeout(1000),
+    )
+
+    expect(title).toBeNull()
+  })
+})

src/utils/__tests__/sessionTitleText.test.ts

@@ -0,0 +1,20 @@
+import { describe, expect, test } from 'bun:test'
+import { cleanSessionTitleSource } from '../sessionTitleText.js'
+
+describe('sessionTitleText', () => {
+  test('converts slash command XML metadata into a user-facing title source', () => {
+    const raw = [
+      '<command-message>frontend-design</command-message>',
+      '<command-name>/frontend-design</command-name>',
+      '<command-args>@website 重新设计首页</command-args>',
+    ].join('\n')
+
+    expect(cleanSessionTitleSource(raw)).toBe('/frontend-design @website 重新设计首页')
+  })
+
+  test('strips non-command internal XML wrappers from title sources', () => {
+    expect(cleanSessionTitleSource('<ide_opened_file>secret.ts</ide_opened_file>\nFix login'))
+      .toBe('Fix login')
+  })
+
+})

src/utils/sessionTitle.ts

@@ -21,9 +21,11 @@ import { logForDebugging } from './debug.js'
 import { safeParseJSON } from './json.js'
 import { lazySchema } from './lazySchema.js'
 import { extractTextContent } from './messages.js'
+import { cleanSessionTitleSource, hasSessionTitleMarkup } from './sessionTitleText.js'
 import { asSystemPrompt } from './systemPromptType.js'
 
 const MAX_CONVERSATION_TEXT = 1000
+const MAX_GENERATED_TITLE_LENGTH = 80
 
 /**
  * Flatten a message array into a single text string for Haiku title input.
@@ -69,6 +71,14 @@ Bad (wrong case): {"title": "Fix Login Button On Mobile"}`
 
 const titleSchema = lazySchema(() => z.object({ title: z.string() }))
 
+export function normalizeGeneratedSessionTitle(title: string): string | null {
+  const cleaned = cleanSessionTitleSource(title)
+  if (!cleaned) return null
+  if (cleaned.length > MAX_GENERATED_TITLE_LENGTH) return null
+  if (hasSessionTitleMarkup(cleaned)) return null
+  return cleaned
+}
+
 /**
  * Generate a sentence-case session title from a description or first message.
  * Returns null on error or if Haiku returns an unparseable response.
@@ -80,7 +90,7 @@ export async function generateSessionTitle(
   description: string,
   signal: AbortSignal,
 ): Promise<string | null> {
-  const trimmed = description.trim()
+  const trimmed = cleanSessionTitleSource(description)
   if (!trimmed) return null
 
   try {
@@ -114,7 +124,9 @@ export async function generateSessionTitle(
     const text = extractTextContent(result.message.content)
 
     const parsed = titleSchema().safeParse(safeParseJSON(text))
-    const title = parsed.success ? parsed.data.title.trim() || null : null
+    const title = parsed.success
+      ? normalizeGeneratedSessionTitle(parsed.data.title)
+      : null
 
     logEvent('tengu_session_title_generated', { success: title !== null })
 

src/utils/sessionTitleText.ts

@@ -0,0 +1,41 @@
+const XML_TAG_BLOCK_PATTERN = /<([a-z][\w-]*)(?:\s[^>]*)?>[\s\S]*?<\/\1>\n?/g
+
+function decodeXmlText(text: string): string {
+  return text
+    .replace(/&lt;/g, '<')
+    .replace(/&gt;/g, '>')
+    .replace(/&quot;/g, '"')
+    .replace(/&#39;/g, "'")
+    .replace(/&amp;/g, '&')
+}
+
+function extractXmlTag(text: string, tag: string): string | undefined {
+  const match = text.match(new RegExp(`<${tag}(?:\\s[^>]*)?>([\\s\\S]*?)<\\/${tag}>`, 'i'))
+  const value = match?.[1]?.trim()
+  return value ? decodeXmlText(value) : undefined
+}
+
+function normalizeTitleWhitespace(text: string): string {
+  return text.replace(/\s+/g, ' ').trim()
+}
+
+/**
+ * Convert system-injected XML wrappers into user-facing text before using a
+ * message as a session title source. Slash commands are stored in transcripts
+ * as command-name/command-args breadcrumbs; titles should show the command the
+ * user typed, not the internal XML transport.
+ */
+export function cleanSessionTitleSource(raw: string): string {
+  const commandName = extractXmlTag(raw, 'command-name')
+  const commandArgs = extractXmlTag(raw, 'command-args')
+  if (commandName) {
+    return normalizeTitleWhitespace([commandName, commandArgs].filter(Boolean).join(' '))
+  }
+
+  const stripped = raw.replace(XML_TAG_BLOCK_PATTERN, ' ')
+  return normalizeTitleWhitespace(stripped)
+}
+
+export function hasSessionTitleMarkup(raw: string): boolean {
+  return /<([a-z][\w-]*)(?:\s[^>]*)?>[\s\S]*?<\/\1>/.test(raw)
+}