fix(ai-vault): prefer Pi/OMP harness names in session history (STA-2467)

Agent Session History ignored Pi `/name` and OMP `/rename` metadata, so
rows stayed on the first user prompt. Read session_info, title slots,
and title_change records in the shared graph parser and keep user titles
above automatic titles and first-prompt fallbacks.

src/main/ai-vault/session-scanner-graph-parsers.ts

@@ -11,14 +11,19 @@ import type {
   SessionAccumulator
 } from './session-scanner-types'
 import {
-  accumulatorFoldResumeState,
   addPreviewContent,
   addPreviewMessage,
+  cloneSessionAccumulator,
   createAccumulator,
   finalizeSession,
   sessionIdFromFileName,
   updateTimeline
 } from './session-scanner-accumulator'
+import {
+  applyGraphSessionTitle,
+  cloneGraphSessionTitleState,
+  type GraphSessionTitleState
+} from './session-scanner-graph-session-title'
 import {
   arrayValue,
   asRecord,
@@ -205,12 +210,14 @@ export async function parseMessageGraphSessionContent(
   })
 }
 
-function consumeMessageGraphRecordLine(accumulator: SessionAccumulator, line: string): void {
+function consumeMessageGraphRecordLine(state: GraphSessionTitleState, line: string): void {
   const record = parseJsonObject(line)
   if (!record) {
     return
   }
+  const { accumulator } = state
   updateTimeline(accumulator, extractString(record.timestamp))
+  applyGraphSessionTitle(state, record)
   if (record.type === 'session') {
     const sessionId = extractString(record.id)
     if (sessionId) {
@@ -234,7 +241,7 @@ function consumeMessageGraphRecordLine(accumulator: SessionAccumulator, line: st
   if (role === 'user' || role === 'assistant') {
     accumulator.messageCount++
     if (role === 'user') {
-      accumulator.title ??= extractMessageText(message)
+      accumulator.fallbackTitle ??= extractMessageText(message)
     } else {
       accumulator.model = extractString(message?.model) ?? accumulator.model
       accumulator.totalTokens += tokenTotal(message?.usage)
@@ -247,14 +254,26 @@ export function createMessageGraphSessionResumeState(
   agent: MessageGraphAgent,
   file: FileWithMtime
 ): ResumableSessionParseState {
-  const state = accumulatorFoldResumeState(
-    createAccumulator({ agent, file, sessionId: sessionIdFromFileName(file.path) }),
-    consumeMessageGraphRecordLine
-  )
+  const resume = createMessageGraphResumeFrom({
+    accumulator: createAccumulator({ agent, file, sessionId: sessionIdFromFileName(file.path) }),
+    source: null
+  })
   // Why: only OMP materializes task-subagent transcripts beside its sessions
   // (in the same-named artifact dir); the row UI shows the count without
   // expanding details. Pi/OpenClaw/Prime Agent have no such layout — skip the readdir.
-  return agent === 'omp' ? withOmpSubagentTranscriptCount(state, file.path) : state
+  return agent === 'omp' ? withOmpSubagentTranscriptCount(resume, file.path) : resume
+}
+
+function createMessageGraphResumeFrom(state: GraphSessionTitleState): ResumableSessionParseState {
+  return {
+    consumeLine: (line) => consumeMessageGraphRecordLine(state, line),
+    clone: () => createMessageGraphResumeFrom(cloneGraphSessionTitleState(state)),
+    touchFile: (nextFile) => {
+      state.accumulator.modifiedAt = nextFile.modifiedAt
+    },
+    finalize: (platform, options) =>
+      finalizeSession(cloneSessionAccumulator(state.accumulator), platform, options)
+  }
 }
 
 async function parseMessageGraphSessionLines(args: {

src/main/ai-vault/session-scanner-graph-session-title.test.ts

@@ -0,0 +1,151 @@
+import { describe, expect, it } from 'vitest'
+import {
+  parseMessageGraphSessionContent,
+  type MessageGraphAgent
+} from './session-scanner-graph-parsers'
+import type { FileWithMtime } from './session-scanner-types'
+
+function graphFile(sessionFile: string): FileWithMtime {
+  return {
+    path: `/tmp/${sessionFile}`,
+    mtimeMs: 1,
+    modifiedAt: '2026-05-01T10:00:00.000Z'
+  }
+}
+
+function jsonl(records: unknown[]): string {
+  return `${records.map((record) => JSON.stringify(record)).join('\n')}\n`
+}
+
+async function parseGraph(
+  agent: MessageGraphAgent,
+  records: unknown[],
+  sessionFile = `${agent}-session.jsonl`
+) {
+  return parseMessageGraphSessionContent(agent, graphFile(sessionFile), jsonl(records), 'darwin')
+}
+
+const firstPrompt = {
+  type: 'message',
+  timestamp: '2026-05-01T10:00:05.000Z',
+  message: { role: 'user', content: 'first user prompt' }
+}
+
+describe('message-graph harness session titles', () => {
+  it('uses the latest Pi session_info.name ahead of the first user prompt', async () => {
+    const session = await parseGraph('pi', [
+      {
+        type: 'session',
+        id: 'pi-session',
+        cwd: '/tmp/pi',
+        timestamp: '2026-05-01T10:00:00.000Z'
+      },
+      firstPrompt,
+      { type: 'session_info', name: 'old name', timestamp: '2026-05-01T10:00:10.000Z' },
+      { type: 'session_info', name: '111', timestamp: '2026-05-01T10:00:20.000Z' }
+    ])
+    expect(session?.title).toBe('111')
+  })
+
+  it('keeps the first Pi user prompt when no session_info name exists', async () => {
+    const session = await parseGraph('pi', [
+      {
+        type: 'session',
+        id: 'pi-session',
+        cwd: '/tmp/pi',
+        timestamp: '2026-05-01T10:00:00.000Z'
+      },
+      firstPrompt
+    ])
+    expect(session?.title).toBe('first user prompt')
+  })
+
+  it('uses the OMP session header title ahead of the first user prompt', async () => {
+    const session = await parseGraph('omp', [
+      {
+        type: 'session',
+        version: 3,
+        id: 'omp-session',
+        cwd: '/tmp/omp',
+        title: 'OMP session title',
+        timestamp: '2026-05-01T10:00:00.000Z'
+      },
+      firstPrompt
+    ])
+    expect(session?.title).toBe('OMP session title')
+  })
+
+  it('lets a later OMP user title replace an automatic title', async () => {
+    const session = await parseGraph('omp', [
+      {
+        type: 'title',
+        v: 1,
+        title: 'auto generated',
+        source: 'auto',
+        updatedAt: '2026-05-01T10:00:00.000Z',
+        pad: ''
+      },
+      {
+        type: 'session',
+        version: 3,
+        id: 'omp-session',
+        cwd: '/tmp/omp',
+        title: 'auto generated',
+        titleSource: 'auto',
+        timestamp: '2026-05-01T10:00:00.000Z'
+      },
+      firstPrompt,
+      {
+        type: 'title_change',
+        title: 'useful title',
+        source: 'user',
+        timestamp: '2026-05-01T10:00:30.000Z'
+      }
+    ])
+    expect(session?.title).toBe('useful title')
+  })
+
+  it('does not let an automatic OMP title overwrite a user title', async () => {
+    const session = await parseGraph('omp', [
+      {
+        type: 'session',
+        version: 3,
+        id: 'omp-session',
+        cwd: '/tmp/omp',
+        title: 'useful title',
+        titleSource: 'user',
+        timestamp: '2026-05-01T10:00:00.000Z'
+      },
+      firstPrompt,
+      {
+        type: 'title_change',
+        title: 'auto generated',
+        source: 'auto',
+        timestamp: '2026-05-01T10:00:30.000Z'
+      }
+    ])
+    expect(session?.title).toBe('useful title')
+  })
+
+  it('uses a user title slot even after a later first prompt', async () => {
+    const session = await parseGraph('omp', [
+      {
+        type: 'title',
+        v: 1,
+        title: 'useful title',
+        source: 'user',
+        updatedAt: '2026-05-01T10:00:00.000Z',
+        pad: ''
+      },
+      {
+        type: 'session',
+        version: 3,
+        id: 'omp-session',
+        cwd: '/tmp/omp',
+        timestamp: '2026-05-01T10:00:00.000Z'
+      },
+      firstPrompt
+    ])
+    expect(session?.title).toBe('useful title')
+  })
+})

src/main/ai-vault/session-scanner-graph-session-title.ts

@@ -0,0 +1,56 @@
+import { cloneSessionAccumulator } from './session-scanner-accumulator'
+import type { SessionAccumulator } from './session-scanner-types'
+import { extractString, normalizeTitleText } from './session-scanner-values'
+
+export type GraphSessionTitleSource = 'user' | 'auto'
+
+export type GraphSessionTitleState = {
+  accumulator: SessionAccumulator
+  source: GraphSessionTitleSource | null
+}
+
+export function cloneGraphSessionTitleState(state: GraphSessionTitleState): GraphSessionTitleState {
+  return {
+    accumulator: cloneSessionAccumulator(state.accumulator),
+    source: state.source
+  }
+}
+
+// Why: Pi `/name` and OMP `/rename` persist as harness metadata, not as the
+// first user prompt. A later user title must replace auto/prompt titles, and
+// an automatic title must never clobber a user title.
+export function applyGraphSessionTitle(
+  state: GraphSessionTitleState,
+  record: Record<string, unknown>
+): void {
+  const incoming = graphSessionTitleFromRecord(record)
+  if (!incoming) {
+    return
+  }
+  if (state.source === 'user' && incoming.source !== 'user') {
+    return
+  }
+  state.accumulator.title = incoming.title
+  state.source = incoming.source
+}
+
+function graphSessionTitleFromRecord(
+  record: Record<string, unknown>
+): { title: string; source: GraphSessionTitleSource } | null {
+  const type = extractString(record.type)
+  if (type === 'session_info') {
+    const title = normalizeTitleText(
+      extractString(record.name) ?? extractString(record.title) ?? ''
+    )
+    return title ? { title, source: 'user' } : null
+  }
+  if (type !== 'title' && type !== 'title_change' && type !== 'session') {
+    return null
+  }
+  const title = normalizeTitleText(extractString(record.title) ?? '')
+  if (!title) {
+    return null
+  }
+  const raw = extractString(record.source) ?? extractString(record.titleSource)
+  return { title, source: raw === 'user' ? 'user' : 'auto' }
+}

src/main/ai-vault/session-scanner-incremental-fixtures.ts

@@ -192,8 +192,8 @@ export function piFixture(): IncrementalAgentFixture {
 
 // OMP is a Pi fork sharing the message-graph format, but keys the model on
 // `model` (not Pi's `modelId`); its own fixture exercises the registry's 'omp'
-// branch and that model-key difference. (The session `title` is included for
-// realism only — the parser derives the title from the first user message.)
+// branch and that model-key difference. The header title outranks the first
+// user prompt, matching a real `/rename`.
 export function ompFixture(): IncrementalAgentFixture {
   return {
     agent: 'omp',

src/main/ai-vault/session-scanner.test.ts

@@ -747,6 +747,7 @@ describe('scanAiVaultSessions', () => {
     const ompSession = result.sessions.find((session) => session.agent === 'omp')
     expect(ompSession?.model).toBe('gpt-5.4-mini')
     expect(ompSession?.totalTokens).toBe(160)
+    expect(ompSession?.title).toBe('OMP session title')
 
     // Prime Agent keeps Pi's `model_change.modelId` key, so the pre-reply model
     // must come through even though no assistant message was written yet.