Merge remote-tracking branch 'origin/master' into worktree/pr576-merge-master-20260723

packages/client/connection/src/client/fixture.ts

@@ -62,13 +62,19 @@ function buildAlphaLog(): SessionEvent[] {
   }
   for (let turn = 0; turn < 60; turn++) {
     push({ type: 'turn/start', data: { turn, trigger: { kind: 'message', source: { kind: 'user' } } } })
-    push({
+    const userSeq = push({
       type: 'user/message', surfaceOp: 'append',
       data: {
         content: text(turn === 59 ? USER_MARKDOWN_LITERAL : `问题 ${turn}：fixture 历史消息，用于翻页与渲染验收。`),
         source: { kind: 'user' },
       },
     })
+    if (turn === 0) {
+      push({
+        type: 'session/title',
+        data: { title: 'Fixture 历史会话', messageSeqs: [userSeq], source: { kind: 'fallback' } },
+      })
+    }
     if (turn % 9 === 4) {
       push({ type: 'context/message', surfaceOp: 'append', data: { content: text(`[fixture] 上下文注入（turn ${turn}）`), source: { kind: 'plugin', plugin: 'fixture' } } })
     }
@@ -187,6 +193,20 @@ function viewFor(event: SessionEvent, log: readonly SessionEvent[]): ToolEventVi
   return undefined
 }
 
+/** Fold the latest fixture title into the host's control-frame projection. */
+function titleFrameOf(id: SessionId, log: readonly SessionEvent[]): Extract<MuxFrame, { type: 'session/title' }> | undefined {
+  const event = log.findLast(item => (item as { type: string }).type === 'session/title')
+  if (event === undefined) return undefined
+  const titleEvent = event as unknown as { seq: number; time: number; data: { title: string } }
+  return {
+    type: 'session/title',
+    sessionId: id,
+    title: titleEvent.data.title,
+    eventSeq: titleEvent.seq,
+    updatedAt: titleEvent.time,
+  }
+}
+
 /**
  * Message-boundary paging (mirrors the host's paging contract): count
  * maxMessages messages
@@ -361,6 +381,10 @@ export function createFixtureApi(): ApiProxy {
     emitMux(view === undefined
       ? { type: 'session/event', sessionId: id, event }
       : { type: 'session/event', sessionId: id, event, view })
+    if ((event as { type: string }).type === 'session/title') {
+      // The raw title is already in this log, so the latest-title fold must find it.
+      emitMux(titleFrameOf(id, log) as Extract<MuxFrame, { type: 'session/title' }>)
+    }
   }
 
   /** At most one in-flight replay per session; cancel clears it. */
@@ -389,6 +413,12 @@ export function createFixtureApi(): ApiProxy {
     appendUser(id: string, msg: string): void {
       append(sid(id), { type: 'user/message', surfaceOp: 'append', data: { content: text(msg), source: { kind: 'user' } } })
     },
+    /** Append a later durable title revision through the normal raw-event + control-frame path. */
+    appendTitle(id: string, title: string): void {
+      const log = logOf(sid(id))
+      const messageSeqs = log.filter(event => event.type === 'user/message').map(event => event.seq)
+      append(sid(id), { type: 'session/title', data: { title, messageSeqs, source: { kind: 'provider', provider: 'fixture' } } })
+    },
     /** Log append WITHOUT the mux emit: a frame lost in transit — history still serves it, the client must repull. */
     appendSilent(id: string, msg: string): void {
       const log = logOf(sid(id))
@@ -506,6 +536,8 @@ export function createFixtureApi(): ApiProxy {
         for (const s of sessions) {
           if (!s.running) continue
           conn.push({ rpcId: mint(), payload: { type: 'session/subscribed', sessionId: s.sessionId, lastSeq: (logs.get(s.sessionId)?.length ?? 0) - 1 } })
+          const title = titleFrameOf(s.sessionId, logs.get(s.sessionId) ?? [])
+          if (title !== undefined) conn.push({ rpcId: mint(), payload: title })
         }
         conn.push({
           rpcId: pendingApprovalRpcId,

packages/client/connection/tests/fixture.spec.ts

@@ -18,6 +18,7 @@ interface TimingHooks {
   setHistoryDelay(ms: number): void
   failNextHistory(): void
   appendUser(id: string, msg: string): void
+  appendTitle(id: string, title: string): void
   appendSilent(id: string, msg: string): void
   breakStreams(): void
 }
@@ -155,7 +156,7 @@ describe('createFixtureApi', () => {
       const envelopes: RpcRequest<MuxFrame>[] = []
       for await (const envelope of api.events.mux(req({}), abort.signal)) {
         envelopes.push(envelope)
-        if (envelopes.length >= 3) abort.abort()
+        if (envelopes.length >= 4) abort.abort()
       }
       return envelopes
     }
@@ -163,10 +164,11 @@ describe('createFixtureApi', () => {
     const second = await openOnce()
     expect(first[0]?.payload).toMatchObject({ type: 'session/subscribed', sessionId: 'fx-alpha' })
     expect((first[0]?.payload as { lastSeq: number }).lastSeq).toBeGreaterThan(0)
-    expect(first[1]?.payload).toMatchObject({ type: 'approval/requested', toolName: 'dangerous_tool' })
-    expect(second[1]?.rpcId).toBe(first[1]?.rpcId) // stable rpcId across replays (host replay semantics)
-    expect(first[2]?.payload).toMatchObject({ type: 'question/requested', sessionId: 'fx-alpha' })
-    expect(second[2]?.rpcId).toBe(first[2]?.rpcId)
+    expect(first[1]?.payload).toMatchObject({ type: 'session/title', sessionId: 'fx-alpha', title: 'Fixture 历史会话' })
+    expect(first[2]?.payload).toMatchObject({ type: 'approval/requested', toolName: 'dangerous_tool' })
+    expect(second[2]?.rpcId).toBe(first[2]?.rpcId) // stable rpcId across replays (host replay semantics)
+    expect(first[3]?.payload).toMatchObject({ type: 'question/requested', sessionId: 'fx-alpha' })
+    expect(second[3]?.rpcId).toBe(first[3]?.rpcId)
   })
 
   it('steer with no replay in flight falls through to a fresh queued turn; non-text blocks stringify empty', async () => {
@@ -279,10 +281,15 @@ describe('createFixtureApi', () => {
     await new Promise(resolve => setTimeout(resolve, 10))
     hooks.appendSilent('fx-alpha', '静默丢帧')
     hooks.appendUser('fx-alpha', '正常直播')
+    hooks.appendTitle('fx-alpha', 'Fixture 修订标题')
     await vi.waitFor(() => {
       expect(seen.some(f => f.type === 'session/event' && JSON.stringify(f.event.data).includes('正常直播'))).toBe(true)
+      expect(seen.some(f => f.type === 'session/title' && f.title === 'Fixture 修订标题')).toBe(true)
     })
     expect(seen.some(f => f.type === 'session/event' && JSON.stringify(f.event.data).includes('静默丢帧'))).toBe(false)
+    const rawTitleIndex = seen.findIndex(f => f.type === 'session/event' && (f.event as { type: string }).type === 'session/title')
+    const titleControlIndex = seen.findIndex(f => f.type === 'session/title' && f.title === 'Fixture 修订标题')
+    expect(titleControlIndex).toBe(rawTitleIndex + 1)
     // But history serves the silent event (the client's repull finds it).
     const repull = await api.sessions.history(req({ sessionId: sid('fx-alpha'), maxMessages: 5 }))
     if (!repull.result.ok) throw new Error('repull failed')

packages/client/runtime/README.md

@@ -2,6 +2,10 @@
 
 Client cordis boot + core services: SlotsService (Service wrapper over SlotCore + 'slots/changed' bridge), SessionsService (list store projection, scope tree, bindings, ancestry), the Session object layer (exported as a type; instances are owned and handed out by SessionsService — the manager/paging internals stay package-internal, tests reach them via src), ClientLoader (`./loader` subpath, statically held by the shell). Contract: api-contracts v3 §4.
 
+## Session title projection
+
+`SessionManager` retains the latest validated `session/title` control snapshot independently of list and session-instance arrival. Newer event seqs replace older snapshots, title timestamps contribute to list recency, and a subscription baseline discards any retained title beyond its `lastSeq` before the optional folded title arrives. Explicit session removal also clears the retained title. The client-facing `SessionSummary.title` is therefore only the actual durable title; `displayTitle` is always present and falls back through the cwd basename and session id. A cold persisted session keeps that fallback until opening or resuming it causes the host to fold and project its log-backed title.
+
 ## Model Experience
 
 None, as the client runtime hosts browser-side services and the session object layer; nothing here reaches a model request.
@@ -15,4 +19,3 @@ None; this package neither assembles nor sends a provider request.
 - **`loader.unload` is a stub (throws not-implemented)** — the full chain (fiber dispose → registration cascade → style removal) lands with the HMR project.
 - **Scope teardown is stage-driven, single-occupant today** — the staged session follows `list.current` exactly (staging is the open signal: the event window opens ⟺ the session is on stage); a removed-while-staged session's scope survives frozen until the stage moves on, not until true observer count reaches zero. Resolution (`cell()`/`binding()`/`scope()`) is pure addressing, render-safe. The staged state can widen to a multi-pane list when concurrent panes land.
 - **Value imports of this package from plugin bundles must use the `/client` subpath** — the bare package name is not in the loader externals table and inlines a second module instance, whose private scope-tag Symbol never matches (the empty-state P0 postmortem).
-- **`SessionSummary.title` is a display projection** — the wire summary carries no title yet; the cwd basename stands in, then the raw id.

packages/client/runtime/src/client/sessions/lineage.ts

@@ -4,9 +4,15 @@
 
 import type { SessionId, SessionSummary } from '@deepseek-ai/dsh-client-connection/client'
 
+/** Host list summary enriched with the latest mux-projected durable title. */
+export interface TitledSessionSummary extends SessionSummary {
+  title?: string
+}
+
 /** One flattened session-list row (summary + lineage indent depth). */
 export interface SessionListEntry {
   sessionId: SessionId
+  title?: string
   updatedAt: number
   running: boolean
   parentSessionId?: SessionId
@@ -21,12 +27,12 @@ export interface SessionListEntry {
  * @param summaries - the host's session.list items.
  * @returns display rows in render order.
  */
-export function flattenLineage(summaries: readonly SessionSummary[]): SessionListEntry[] {
-  const byId = new Map<SessionId, SessionSummary>()
+export function flattenLineage(summaries: readonly TitledSessionSummary[]): SessionListEntry[] {
+  const byId = new Map<SessionId, TitledSessionSummary>()
   for (const s of summaries) byId.set(s.sessionId, s)
 
-  const children = new Map<SessionId, SessionSummary[]>()
-  const roots: SessionSummary[] = []
+  const children = new Map<SessionId, TitledSessionSummary[]>()
+  const roots: TitledSessionSummary[] = []
   for (const s of summaries) {
     if (s.parentSessionId !== undefined && byId.has(s.parentSessionId)) {
       const list = children.get(s.parentSessionId) ?? []
@@ -37,12 +43,12 @@ export function flattenLineage(summaries: readonly SessionSummary[]): SessionLis
     }
   }
 
-  const byUpdatedDesc = (a: SessionSummary, b: SessionSummary): number => b.updatedAt - a.updatedAt
+  const byUpdatedDesc = (a: TitledSessionSummary, b: TitledSessionSummary): number => b.updatedAt - a.updatedAt
   roots.sort(byUpdatedDesc)
 
   const out: SessionListEntry[] = []
   const visited = new Set<SessionId>()
-  const walk = (s: SessionSummary, depth: number): void => {
+  const walk = (s: TitledSessionSummary, depth: number): void => {
     if (visited.has(s.sessionId)) {
       console.warn(`[web-runtime] lineage cycle at ${s.sessionId}; emitting as root`)
       return

packages/client/runtime/src/client/sessions/manager.ts

@@ -4,7 +4,7 @@
 
 import type { IApiClient, HostFrame, MuxFrame, RpcError, RpcRequest, RpcResult, SessionId, SessionSummary } from '@deepseek-ai/dsh-client-connection/client'
 import { transportError } from '@deepseek-ai/dsh-client-connection/client'
-import type { SessionListEntry } from './lineage.ts'
+import type { SessionListEntry, TitledSessionSummary } from './lineage.ts'
 import { flattenLineage } from './lineage.ts'
 import { Notifier } from './notifier.ts'
 import { Session } from './session.ts'
@@ -19,6 +19,13 @@ export interface SessionListSnapshot {
 /** Per-session cap for pre-instantiation approval/question buffering (low-frequency frames; a few dozen covers any real backlog). */
 const PENDING_BUFFER_CAP = 32
 
+/** Latest title control snapshot retained independently of list/instance arrival. */
+interface SessionTitleSnapshot {
+  title: string
+  eventSeq: number
+  updatedAt: number
+}
+
 /** Instance cluster + frame entry + the session list (see the web client architecture RFC). */
 export class SessionManager {
   private readonly sessions = new Map<SessionId, Session>()
@@ -27,6 +34,7 @@ export class SessionManager {
    *  drop-and-backfill path; replayed and cleared on instantiation. Bounded per session (these
    *  frames are low-frequency; overflow drops oldest) and dropped on session-removed (audit S7). */
   private readonly pendingBuffers = new Map<SessionId, RpcRequest<MuxFrame>[]>()
+  private readonly titleSnapshots = new Map<SessionId, SessionTitleSnapshot>()
   private summaries: SessionSummary[] = []
   private listState: 'idle' | 'loading' | 'error' = 'idle'
   private listError: RpcError | null = null
@@ -158,6 +166,24 @@ export class SessionManager {
   handleMuxEnvelope(envelope: RpcRequest<MuxFrame>): void {
     const frame = envelope.payload
     if (frame.type === 'stream/error') return // Controller already treats this as stream failure
+    if (frame.type === 'session/title') {
+      const current = this.titleSnapshots.get(frame.sessionId)
+      if (current !== undefined && current.eventSeq >= frame.eventSeq) return
+      this.titleSnapshots.set(frame.sessionId, {
+        title: frame.title,
+        eventSeq: frame.eventSeq,
+        updatedAt: frame.updatedAt,
+      })
+      this.notifier.markDirty()
+      return
+    }
+    if (frame.type === 'session/subscribed') {
+      const current = this.titleSnapshots.get(frame.sessionId)
+      if (current !== undefined && current.eventSeq > frame.lastSeq) {
+        this.titleSnapshots.delete(frame.sessionId)
+        this.notifier.markDirty()
+      }
+    }
     const session = this.sessions.get(frame.sessionId)
     if (session === undefined) {
       // Approval/question frames never hit history: buffer for replay on instantiation;
@@ -204,6 +230,7 @@ export class SessionManager {
         this.summaries = this.summaries.filter(s => s.sessionId !== frame.sessionId)
         this.sessions.get(frame.sessionId)?.handleRemoved() // instance survives (resident-instance rule), only flagged in the snapshot
         this.pendingBuffers.delete(frame.sessionId) // a removed session's buffered frames must not replay on a future instantiation
+        this.titleSnapshots.delete(frame.sessionId)
         this.notifier.markDirty()
         return
       }
@@ -230,12 +257,19 @@ export class SessionManager {
   }
 
   private buildListSnapshot(): SessionListSnapshot {
-    const fresh = flattenLineage(this.summaries)
+    const merged: TitledSessionSummary[] = this.summaries.map((summary) => {
+      const title = this.titleSnapshots.get(summary.sessionId)
+      return title === undefined
+        ? summary
+        : { ...summary, title: title.title, updatedAt: Math.max(summary.updatedAt, title.updatedAt) }
+    })
+    const fresh = flattenLineage(merged)
     const items = fresh.map((entry) => {
       const prev = this.entryCache.get(entry.sessionId)
       if (
         prev !== undefined && prev.updatedAt === entry.updatedAt && prev.running === entry.running
-        && prev.parentSessionId === entry.parentSessionId && prev.cwd === entry.cwd && prev.depth === entry.depth
+        && prev.parentSessionId === entry.parentSessionId && prev.cwd === entry.cwd
+        && prev.title === entry.title && prev.depth === entry.depth
       ) return prev
       this.entryCache.set(entry.sessionId, entry)
       return entry

packages/client/runtime/src/client/sessions/service.ts

@@ -25,7 +25,10 @@ import type { Session } from './session.ts'
 /** Session list row projected from the host list RPC plus live stream increments. */
 export interface SessionSummary {
   id: SessionId
-  title: string
+  /** Latest durable log-backed title, absent until the host projects one. */
+  title?: string
+  /** Human-facing label: durable title, project basename, then session id. */
+  displayTitle: string
   cwd?: string
   parentId?: SessionId
   running: boolean
@@ -62,10 +65,11 @@ export function scopeOf(ctx: Context): SessionId | undefined {
 function sessionScope(): void {}
 
 /**
- * Display title projection. The wire summary carries no title yet (P-I
- * ledger): the project directory's basename stands in, then the raw id.
+ * Display title projection: durable title, project directory basename, then
+ * the raw id.
  */
-function titleOf(cwd: string | undefined, id: SessionId): string {
+function displayTitleOf(title: string | undefined, cwd: string | undefined, id: SessionId): string {
+  if (title !== undefined) return title
   if (cwd !== undefined && cwd !== '') {
     const base = cwd.replace(/[/\\]+$/, '').split(/[/\\]/).pop()
     if (base !== undefined && base !== '') return base
@@ -259,9 +263,10 @@ export class SessionsService {
       ids.push(entry.sessionId)
       byId[entry.sessionId] = {
         id: entry.sessionId,
-        title: titleOf(entry.cwd, entry.sessionId),
+        displayTitle: displayTitleOf(entry.title, entry.cwd, entry.sessionId),
         running: entry.running,
         updatedAt: entry.updatedAt,
+        ...(entry.title !== undefined ? { title: entry.title } : {}),
         ...(entry.cwd !== undefined ? { cwd: entry.cwd } : {}),
         ...(entry.parentSessionId !== undefined ? { parentId: entry.parentSessionId } : {}),
       }

packages/client/runtime/tests/manager.spec.ts

@@ -89,6 +89,66 @@ describe('list lifecycle', () => {
     expect(result).toMatchObject({ ok: true, value: { sessionId: S2 } })
     expect(manager.getListSnapshot().items.map(i => i.sessionId)).toEqual([S2])
   })
+
+  it('retains monotonic title snapshots before list arrival, merges recency, and clears them on removal', async () => {
+    const api = new FakeApiClient()
+    const manager = new SessionManager(api)
+    manager.handleMuxEnvelope({
+      rpcId: 'title-new' as never,
+      payload: { type: 'session/title', sessionId: S1, title: 'Newest', eventSeq: 4, updatedAt: 300 },
+    })
+    manager.handleMuxEnvelope({
+      rpcId: 'title-stale' as never,
+      payload: { type: 'session/title', sessionId: S1, title: 'Stale', eventSeq: 3, updatedAt: 900 },
+    })
+    manager.handleMuxEnvelope({
+      rpcId: 'title-equal' as never,
+      payload: { type: 'session/title', sessionId: S1, title: 'Equal', eventSeq: 4, updatedAt: 901 },
+    })
+    api.onList = () => Promise.resolve(ok({
+      items: [summary(S1), summary(S2, { updatedAt: 200 })] as never[],
+    }))
+    await manager.refreshList()
+
+    const titled = manager.getListSnapshot()
+    expect(titled.items.map(item => item.sessionId)).toEqual([S1, S2])
+    expect(titled.items[0]).toMatchObject({ title: 'Newest', updatedAt: 300 })
+    expect(titled.items[1]?.title).toBeUndefined()
+
+    manager.handleHostEnvelope({ rpcId: 'removed' as never, payload: { type: 'host/session-removed', sessionId: S1 } })
+    manager.handleHostEnvelope({ rpcId: 'readded' as never, payload: { type: 'host/session-added', sessionId: S1 } })
+    expect(manager.getListSnapshot().items.find(item => item.sessionId === S1)?.title).toBeUndefined()
+  })
+
+  it('drops a retained title beyond the subscription baseline before accepting its durable replay', async () => {
+    const api = new FakeApiClient()
+    api.onList = () => Promise.resolve(ok({ items: [summary(S1)] as never[] }))
+    const manager = new SessionManager(api)
+    await manager.refreshList()
+    manager.handleMuxEnvelope({
+      rpcId: 'title-unflushed' as never,
+      payload: { type: 'session/title', sessionId: S1, title: 'Unflushed', eventSeq: 4, updatedAt: 400 },
+    })
+
+    manager.handleMuxEnvelope({
+      rpcId: 'subscribed-recovered' as never,
+      payload: { type: 'session/subscribed', sessionId: S1, lastSeq: 2 },
+    })
+    expect(manager.getListSnapshot().items[0]?.title).toBeUndefined()
+    expect(manager.getListSnapshot().items[0]?.updatedAt).toBe(100)
+
+    manager.handleMuxEnvelope({
+      rpcId: 'title-durable' as never,
+      payload: { type: 'session/title', sessionId: S1, title: 'Durable', eventSeq: 2, updatedAt: 200 },
+    })
+    expect(manager.getListSnapshot().items[0]).toMatchObject({ title: 'Durable', updatedAt: 200 })
+
+    manager.handleMuxEnvelope({
+      rpcId: 'subscribed-current' as never,
+      payload: { type: 'session/subscribed', sessionId: S1, lastSeq: 2 },
+    })
+    expect(manager.getListSnapshot().items[0]).toMatchObject({ title: 'Durable', updatedAt: 200 })
+  })
 })
 
 describe('host frame routing', () => {

packages/client/runtime/tests/sessions-service.spec.ts

@@ -41,16 +41,21 @@ async function feedList(b: Bench, rows: { id: string; cwd?: string; parentId?: s
 }
 
 describe('list store projection', () => {
-  it('projects ids/byId with cwd-basename titles (id fallback) and parent links', async () => {
+  it('projects durable titles separately from cwd/id display fallbacks and parent links', async () => {
     const b = bench()
+    b.svc.manager.handleMuxEnvelope({
+      rpcId: 'title' as never,
+      payload: { type: 'session/title', sessionId: sid('s1'), title: 'Durable title', eventSeq: 2, updatedAt: 3 },
+    })
     await feedList(b, [
       { id: 's1', cwd: '/home/u/proj-a/' },
       { id: 's2', parentId: 's1', running: true },
     ])
     const state = b.svc.list.getSnapshot()
     expect(state.ids).toEqual(['s1', 's2'])
-    expect(state.byId[sid('s1')]).toMatchObject({ title: 'proj-a', cwd: '/home/u/proj-a/' })
-    expect(state.byId[sid('s2')]).toMatchObject({ title: 's2', parentId: 's1', running: true })
+    expect(state.byId[sid('s1')]).toMatchObject({ title: 'Durable title', displayTitle: 'Durable title', cwd: '/home/u/proj-a/' })
+    expect(state.byId[sid('s2')]).toMatchObject({ displayTitle: 's2', parentId: 's1', running: true })
+    expect(state.byId[sid('s2')]?.title).toBeUndefined()
   })
 
   it('reflects live increments (host stream via manager) into the store', async () => {
@@ -273,12 +278,13 @@ describe('create', () => {
 })
 
 describe('coverage tails (branch duals)', () => {
-  it('titleOf falls back to the id for empty and separator-only cwd', async () => {
+  it('displayTitleOf falls back to the id for empty and separator-only cwd', async () => {
     const b = bench()
     await feedList(b, [{ id: 'no-base', cwd: '///' }, { id: 'empty-cwd', cwd: '' }])
     const { byId } = b.svc.list.getSnapshot()
-    expect(byId[sid('no-base')]?.title).toBe('no-base')
-    expect(byId[sid('empty-cwd')]?.title).toBe('empty-cwd')
+    expect(byId[sid('no-base')]?.displayTitle).toBe('no-base')
+    expect(byId[sid('empty-cwd')]?.displayTitle).toBe('empty-cwd')
+    expect(byId[sid('no-base')]?.title).toBeUndefined()
   })
 
   it('binding for an unknown session returns undefined and leaves the staged scope intact', async () => {

packages/client/ui-conversation/src/client/skeleton/ConversationRoot.tsx

@@ -90,7 +90,7 @@ export function ConversationRoot({
                     disabled={last}
                     onClick={() => { open(s.id) }}
                   >
-                    {s.title}
+                    {s.displayTitle}
                   </button>
                 </span>
               )

packages/client/ui-conversation/tests/apply-inject.spec.tsx

@@ -51,7 +51,7 @@ async function bench() {
 
   const listStore = createSnapshotStore<SessionListState>({
     ids: [ROOT],
-    byId: { [ROOT]: { id: ROOT, title: 'R', cwd: '/proj', running: false, updatedAt: 1 } },
+    byId: { [ROOT]: { id: ROOT, title: 'R', displayTitle: 'R', cwd: '/proj', running: false, updatedAt: 1 } },
     current: ROOT,
   } as SessionListState)
   const sessionFake = {

packages/client/ui-conversation/tests/chat-apply.spec.tsx

@@ -26,8 +26,8 @@ async function bench() {
   const listStore = createSnapshotStore<SessionListState>({
     ids: [ROOT, CHILD],
     byId: {
-      [ROOT]: { id: ROOT, title: 'R', running: false, updatedAt: 1 },
-      [CHILD]: { id: CHILD, title: 'C', parentId: ROOT, running: false, updatedAt: 2 },
+      [ROOT]: { id: ROOT, title: 'R', displayTitle: 'R', running: false, updatedAt: 1 },
+      [CHILD]: { id: CHILD, title: 'C', displayTitle: 'C', parentId: ROOT, running: false, updatedAt: 2 },
     },
     current: undefined,
   } as SessionListState)

packages/client/ui-conversation/tests/chat-stats-bash-sample.spec.tsx

@@ -122,8 +122,8 @@ describe('bash sample row', () => {
     return createSnapshotStore<SessionListState>({
       ids: [ROOT, CHILD],
       byId: {
-        [ROOT]: { id: ROOT, title: 'r', running: false, updatedAt: 0 },
-        [CHILD]: { id: CHILD, title: 'c', parentId: ROOT, running: false, updatedAt: 0 },
+        [ROOT]: { id: ROOT, title: 'r', displayTitle: 'r', running: false, updatedAt: 0 },
+        [CHILD]: { id: CHILD, title: 'c', displayTitle: 'c', parentId: ROOT, running: false, updatedAt: 0 },
       },
       current: undefined,
     } as SessionListState)
@@ -157,7 +157,7 @@ describe('bash sample row', () => {
     const orphan = 'late-child' as SessionId
     store.update((d) => {
       d.ids.push(orphan)
-      d.byId[orphan] = { id: orphan, title: 'l', running: false, updatedAt: 0 }
+      d.byId[orphan] = { id: orphan, title: 'l', displayTitle: 'l', running: false, updatedAt: 0 }
     })
     const view = render(<BashRow {...rowProps(orphan, { store })} />)
     expect(view.container.querySelector('[data-sample="bash-global"]')).not.toBeNull()

packages/client/ui-conversation/tests/selection-survival.spec.ts

@@ -123,23 +123,25 @@ describe('selection survives on the store seat', () => {
     expect(two.store.getSnapshot().selection).toEqual({ turnSeq: 9, callId: 'z' })
   })
 
-  it('a title-upgrading list refresh keeps instance identity and the selection value', async () => {
+  it('a display-title-upgrading list refresh keeps instance identity and the selection value', async () => {
     const b = bench()
     // First-send shape: client-side create inserts the row without cwd (title = bare id).
     b.api.onCreate = () => Promise.resolve(ok({ sessionId: sid('s1') }))
     const id = await b.sessions.create({})
     await flush()
-    expect(b.sessions.list.getSnapshot().byId[id]?.title).toBe('s1')
+    expect(b.sessions.list.getSnapshot().byId[id]).toMatchObject({ displayTitle: 's1' })
+    expect(b.sessions.list.getSnapshot().byId[id]?.title).toBeUndefined()
 
     const store = storeFor(b, 'conversation', id)
     store.actions.select({ turnSeq: 3, callId: 'c1' })
     store.actions.setDraft('half-typed')
 
-    // The late list refresh lands (host knows the cwd → formal title).
+    // The late list refresh lands (host knows the cwd → better fallback label).
     feed(b, [{ id: 's1', cwd: '/w/proj-a' }])
     await b.sessions.manager.refreshList()
     await flush()
-    expect(b.sessions.list.getSnapshot().byId[id]?.title).toBe('proj-a')
+    expect(b.sessions.list.getSnapshot().byId[id]).toMatchObject({ displayTitle: 'proj-a' })
+    expect(b.sessions.list.getSnapshot().byId[id]?.title).toBeUndefined()
 
     const after = storeFor(b, 'conversation', id)
     expect(after).toBe(store)

packages/client/ui-conversation/tests/skeleton-branches.spec.tsx

@@ -46,7 +46,7 @@ function listHook(rows: { id: string; title: string; cwd?: string; parentId?: st
   const store = createSnapshotStore<SessionListState>({
     ids: rows.map(r => r.id as SessionId),
     byId: Object.fromEntries(rows.map(r => [r.id, {
-      id: r.id as SessionId, title: r.title, running: false, updatedAt: 1,
+      id: r.id as SessionId, title: `durable ${r.title}`, displayTitle: r.title, running: false, updatedAt: 1,
       ...(r.cwd !== undefined ? { cwd: r.cwd } : {}),
       ...(r.parentId !== undefined ? { parentId: r.parentId as SessionId } : {}),
     }])),

packages/client/ui-conversation/tests/skeleton.spec.tsx

@@ -53,7 +53,7 @@ function fakeSessions(rows: { id: string; title: string; cwd?: string; parentId?
   const store = createSnapshotStore<SessionListState>({
     ids: rows.map(r => sid(r.id)),
     byId: Object.fromEntries(rows.map(r => [r.id, {
-      id: sid(r.id), title: r.title, running: false, updatedAt: 1,
+      id: sid(r.id), title: `durable ${r.title}`, displayTitle: r.title, running: false, updatedAt: 1,
       ...(r.cwd !== undefined ? { cwd: r.cwd } : {}),
       ...(r.parentId !== undefined ? { parentId: sid(r.parentId) } : {}),
     }])),

packages/client/ui-sidebar/src/client/tree.ts

@@ -154,7 +154,7 @@ function sessionRow(g: Group, s: SessionSummary, depth: number, hasChildren: boo
     type: 'session',
     id: s.id,
     groupKey: g.key,
-    title: s.title,
+    title: s.displayTitle,
     depth,
     hasChildren,
     expanded,
@@ -183,7 +183,7 @@ function flattenVisible(g: Group, expandedSessions: ReadonlySet<string>, rows: S
 function searchVisible(g: Group, q: string): Set<SessionId> {
   const visible = new Set<SessionId>()
   for (const m of g.summaries.values()) {
-    if (!m.title.toLowerCase().includes(q)) continue
+    if (!m.displayTitle.toLowerCase().includes(q)) continue
     let cur: SessionSummary | undefined = m
     while (cur !== undefined && !visible.has(cur.id)) {
       visible.add(cur.id)
@@ -213,9 +213,9 @@ function flattenSearch(g: Group, visible: ReadonlySet<SessionId>, rows: SidebarR
  *
  * Normal mode: every project row shows; sessions show under expanded
  * projects, descending only into expanded sessions. Search mode (non-blank
- * query, case-insensitive title substring): expansion state is ignored —
+ * query, case-insensitive display-title substring): expansion state is ignored —
  * matched sessions and their ancestor chains are forced visible, groups
- * without a title or label hit are dropped, and a label-only hit keeps the
+ * without a display-title or label hit are dropped, and a label-only hit keeps the
  * bare project row.
  * @param list - sessions list snapshot.
  * @param view - local expansion arrays and search query.

packages/client/ui-sidebar/tests/apply.spec.tsx

@@ -23,7 +23,7 @@ async function bench() {
   await ctx.plugin(SlotsService).await()
   const list = createSnapshotStore<SessionListState>({
     ids: [sid('a')],
-    byId: { [sid('a')]: { id: sid('a'), title: 'alpha', cwd: '/proj', running: false, updatedAt: 1 } },
+    byId: { [sid('a')]: { id: sid('a'), title: 'alpha', displayTitle: 'alpha', cwd: '/proj', running: false, updatedAt: 1 } },
     current: undefined,
   })
   const sessions = { list, create: vi.fn(async () => sid('minted')), open: vi.fn() }

packages/client/ui-sidebar/tests/sidebar-root.spec.tsx

@@ -38,6 +38,7 @@ function summary(init: SummaryInit): SessionSummary {
   const s: SessionSummary = {
     id: sid(init.id),
     title: init.title ?? init.id,
+    displayTitle: init.title ?? init.id,
     running: init.running ?? false,
     updatedAt: init.updatedAt ?? 0,
   }

packages/client/ui-sidebar/tests/tree.spec.ts

@@ -11,6 +11,7 @@ const sid = (s: string) => s as SessionId
 interface SummaryInit {
   id: string
   title?: string
+  displayTitle?: string
   cwd?: string
   parentId?: string
   running?: boolean
@@ -20,10 +21,11 @@ interface SummaryInit {
 function summary(init: SummaryInit): SessionSummary {
   const s: SessionSummary = {
     id: sid(init.id),
-    title: init.title ?? init.id,
+    displayTitle: init.displayTitle ?? init.title ?? init.id,
     running: init.running ?? false,
     updatedAt: init.updatedAt ?? 0,
   }
+  if (init.title !== undefined) s.title = init.title
   if (init.cwd !== undefined) s.cwd = init.cwd
   if (init.parentId !== undefined) s.parentId = sid(init.parentId)
   return s
@@ -211,6 +213,15 @@ describe('deriveRows search', () => {
     const rows = deriveRows(list, view({ query: '   ' }))
     expect(rows.every(r => r.type === 'project')).toBe(true)
   })
+
+  it('matches the effective display title when no durable title is available', () => {
+    const fallback = listOf(summary({ id: 'raw-id', displayTitle: 'project fallback', cwd: '/elsewhere' }))
+    const rows = deriveRows(fallback, view({ query: 'fallback' }))
+    expect(rows).toEqual([
+      expect.objectContaining({ type: 'project', key: '/elsewhere' }),
+      expect.objectContaining({ type: 'session', id: 'raw-id', title: 'project fallback' }),
+    ])
+  })
 })
 
 describe('formatRelativeTime', () => {

packages/client/web/README.md

@@ -4,6 +4,8 @@ Web shell library: `bootWebShell(el, seams?)` mounts the whole client — loader
 
 The optional `seams` parameter forwards the client loader's `fetchBundle`/`executeBundle` transport overrides (`BootSeams`); production callers omit it — it exists for test environments where `<script>` execution cannot reach the page context (jsdom).
 
+The shell owns browser-title projection. With a selected session carrying a durable title, it renders `<session title> — <existing HTML title>` and reacts to later title revisions; no selection or a selected untitled session preserves the existing title, and shell unmount restores it. The existing HTML title remains the configurable product suffix.
+
 ## Model Experience
 
 None, as the entry shell boots the browser plugin tree; nothing here reaches a model request.

packages/client/web/src/DocumentTitle.tsx

@@ -0,0 +1,22 @@
+import { useEffect, useRef } from 'react'
+
+/** Props for the shell-owned browser title projection. */
+export interface DocumentTitleProps {
+  /** Durable title of the selected session, or undefined for the product title. */
+  title?: string
+}
+
+/**
+ * Project the selected durable session title into the browser title and
+ * restore the shell's original product title when unmounted.
+ * @param props - selected session title projection.
+ * @returns no rendered content.
+ */
+export function DocumentTitle({ title }: DocumentTitleProps): null {
+  const original = useRef(document.title)
+  useEffect(() => {
+    document.title = title === undefined ? original.current : `${title} — ${original.current}`
+    return () => { document.title = original.current }
+  }, [title])
+  return null
+}

packages/client/web/src/app.tsx

@@ -6,6 +6,9 @@
  */
 import type { ReactNode } from 'react'
 import type { Context } from 'cordis'
+import type { SessionsService } from '@deepseek-ai/dsh-client-runtime/client'
+import { bindSnapshotSelector } from '@deepseek-ai/dsh-client-web-react'
+import { DocumentTitle } from './DocumentTitle.tsx'
 // Type-only: pulls the runtime's SlotMap declaration merge (the 'root' key) into this program.
 import type {} from '@deepseek-ai/dsh-client-runtime/client'
 
@@ -24,5 +27,20 @@ export interface AssemblyDeps {
  */
 export function buildRenderApp(deps: AssemblyDeps): () => ReactNode {
   const { ctx } = deps
-  return () => ctx.slots.renderSlot('root', {})
+  const sessions = ctx.get('sessions') as SessionsService | undefined
+  if (sessions === undefined) throw new Error('shell assembly: sessions service unavailable')
+  const useSessions = bindSnapshotSelector(sessions.list)
+  const SessionDocumentTitle = (): ReactNode => {
+    const title = useSessions((state) => {
+      const id = state.current
+      return id === undefined ? undefined : state.byId[id]?.title
+    })
+    return <DocumentTitle {...title === undefined ? {} : { title }} />
+  }
+  return () => (
+    <>
+      <SessionDocumentTitle />
+      {ctx.slots.renderSlot('root', {})}
+    </>
+  )
 }

packages/client/web/src/index.ts

@@ -8,4 +8,5 @@
 export { bootWebShell } from './boot.tsx'
 export { AppRoot, type AppRootProps } from './AppRoot.tsx'
 export { buildRenderApp, type AssemblyDeps } from './app.tsx'
+export { DocumentTitle, type DocumentTitleProps } from './DocumentTitle.tsx'
 export { seedModules } from './seed.ts'

packages/client/web/tests/boot.spec.tsx

@@ -39,7 +39,7 @@ window.DSHClientProxy.loadPlugin({
     return {
       apply: (ctx) => {
         ctx.plugin(SlotsService)
-        const list = createSnapshotStore({ ids: ['s1'], byId: { s1: { id: 's1', title: 'S1', running: false, updatedAt: 1 } }, current: 's1' })
+        const list = createSnapshotStore({ ids: ['s1'], byId: { s1: { id: 's1', title: 'S1', displayTitle: 'S1', running: false, updatedAt: 1 } }, current: 's1' })
         ctx.provide('sessions', {
           list,
           cell: (id) => (id === 's1' ? { sessionId: 's1', session: { getSnapshot: () => ({}), subscribe: () => () => {} } } : undefined),
@@ -134,6 +134,7 @@ afterEach(() => {
   delete win.__TEST_RUNTIME_STORE__
   document.body.innerHTML = ''
   document.head.querySelectorAll('script').forEach((s) => { s.remove() })
+  document.title = ''
 })
 
 /** Hand the real runtime surface to the stub bundle (runtime is not a seeded library). */
@@ -147,6 +148,7 @@ describe('bootWebShell (real loader + real script execution)', () => {
     win.__DSH_BOOT__ = { plugins: bootPlugins() }
     seedSlotsService()
     const el = mountPoint()
+    document.title = 'DeepSeek Harness'
     let unmount: (() => void) | undefined
     act(() => { unmount = bootWebShell(el, seams(fakeBundles())) })
     expect(el.textContent).toContain('HARNESS')
@@ -155,9 +157,11 @@ describe('bootWebShell (real loader + real script execution)', () => {
     await flushLoader()
     expect(el.querySelector('[data-testid="fake-frame"]')).not.toBeNull()
     expect(el.textContent).not.toContain('HARNESS')
+    expect(document.title).toBe('S1 — DeepSeek Harness')
 
     act(() => { unmount!() })
     expect(el.childElementCount).toBe(0)
+    expect(document.title).toBe('DeepSeek Harness')
   })
 
   it('store seat round-trips through the entry props (useStore + actions)', async () => {
@@ -218,6 +222,9 @@ describe('buildRenderApp — assembly contract', () => {
     const ctx = new Context()
     const fiber = ctx.plugin(SlotsService)
     await fiber.await()
+    ctx.provide('sessions', {
+      list: createSnapshotStore({ ids: [], byId: {}, current: undefined }),
+    })
     const renderApp = buildRenderApp({ ctx, requireModule: () => undefined })
     expect(renderApp).toBeTypeOf('function')
     // No renderer installed: the one-line shell must surface the boot-order error.

packages/client/web/tests/document-title.spec.tsx

@@ -0,0 +1,28 @@
+// @vitest-environment jsdom
+import { afterEach, describe, expect, it } from 'vitest'
+import { cleanup, render } from '@testing-library/react'
+import { DocumentTitle } from '../src/DocumentTitle.tsx'
+
+afterEach(() => {
+  cleanup()
+  document.title = ''
+})
+
+describe('DocumentTitle', () => {
+  it('preserves the product title without a durable title and restores it on unmount', () => {
+    document.title = 'DeepSeek Harness'
+    const mounted = render(<DocumentTitle />)
+    expect(document.title).toBe('DeepSeek Harness')
+
+    mounted.rerender(<DocumentTitle title="First title" />)
+    expect(document.title).toBe('First title — DeepSeek Harness')
+
+    mounted.rerender(<DocumentTitle title="Revised title" />)
+    expect(document.title).toBe('Revised title — DeepSeek Harness')
+
+    mounted.rerender(<DocumentTitle />)
+    expect(document.title).toBe('DeepSeek Harness')
+    mounted.unmount()
+    expect(document.title).toBe('DeepSeek Harness')
+  })
+})

packages/cordis/tool-cordis/src/api-catalog.ts

@@ -1455,7 +1455,7 @@ export const TYPE_API: readonly TypeApiEntry[] = [
   },
   {
     name: 'GenerateOptions',
-    declaration: 'export interface GenerateOptions {\n    provider: string;\n    model: string;\n    messages: Message[];\n    system?: string;\n    tools?: ToolSchema[];\n    temperature?: number;\n    maxTokens?: number;\n    stop?: string[];\n    signal?: AbortSignal;\n    sessionId?: Branded<\'SessionId\'>;\n    purpose?: \'compaction\';\n}',
+    declaration: 'export interface GenerateOptions {\n    provider: string;\n    model: string;\n    messages: Message[];\n    system?: string;\n    tools?: ToolSchema[];\n    temperature?: number;\n    maxTokens?: number;\n    stop?: string[];\n    signal?: AbortSignal;\n    sessionId?: Branded<\'SessionId\'>;\n    purpose?: \'compaction\' | \'session-title\';\n}',
   },
   {
     name: 'GenericCallView',

packages/host/apiproxy/README.md

@@ -8,6 +8,8 @@ Wire messages form a four-quadrant discriminated union — who initiates × requ
 
 The layering/protocol decisions are recorded in the [GUI layering and RPC protocol RFC](../../../.agents/notes/implemented/architecture/2026-07-19-gui-layering-and-rpc-protocol.md); the browser-side consumption architecture in the [web client architecture RFC](../../../.agents/notes/implemented/architecture/2026-07-19-gui-web-client-architecture.md).
 
+The mux stream projects the latest log-backed title as a validated `session/title` control frame after each attached-session subscription baseline and immediately after the corresponding live raw title event. This projection does not add titles to `session.list`; cold sessions remain metadata-only there until opening or resuming attaches their logs.
+
 ## Carrier layer (`/client` + root)
 
 `AbstractApiClient` holds every protocol invariant — rpcId minting, envelope wrap/unwrap, zod parsing, SSE frame decoding, unary timeout, microtask-batched envelope observation (`subscribeEnvelopes`) — while platform subclasses supply only the `doFetch` transport aspect. `InProcessApiClient` over `toFetchHandler(api)` is the isomorphic point: the full wire serialization/validation path with no network, used by `dsh -p` headless.

packages/host/apiproxy/src/api/events.schema.ts

@@ -26,6 +26,7 @@ export const askUserQuestionItemSchema = z.object({
 export const muxFrameSchema = z.discriminatedUnion('type', [
   z.object({ type: z.literal('session/event'), sessionId: sessionIdSchema, event: sessionEventSchema, view: toolEventViewSchema.optional() }),
   z.object({ type: z.literal('session/subscribed'), sessionId: sessionIdSchema, lastSeq: z.number().int() }),
+  z.object({ type: z.literal('session/title'), sessionId: sessionIdSchema, title: z.string().min(1), eventSeq: z.number().int().nonnegative(), updatedAt: z.number() }),
   z.object({ type: z.literal('approval/requested'), sessionId: sessionIdSchema, approvalId: approvalRequestIdSchema, toolName: z.string(), callId: z.string().optional(), reason: z.string().optional() }),
   z.object({ type: z.literal('approval/resolved'), sessionId: sessionIdSchema, approvalId: approvalRequestIdSchema, outcome: z.union([z.literal('allowed-once'), z.literal('rejected'), z.literal('cancelled'), z.literal('unavailable')]) }),
   // Non-empty by wire contract: the user-interaction service rejects empty

packages/host/apiproxy/src/api/events.ts

@@ -33,8 +33,9 @@ export type ToolEventView =
 export interface EventsApi {
   /**
    * All-session aggregated mux stream. On open, emits a subscribed control frame for every
-   * attached session and replays each session's still-pending approval/question requested
-   * frames (rpcId reused verbatim — the refresh-recovery baseline).
+   * attached session followed by its optional latest title snapshot, then replays each
+   * session's still-pending approval/question requested frames (rpcId reused verbatim — the
+   * refresh-recovery baseline).
    * since: resume seam, unimplemented in v1 (ignored if passed); reconnection = reopen the
    * stream + refetch history.
    */
@@ -54,6 +55,7 @@ export interface EventsApi {
 export type MuxFrame =
   | { type: 'session/event'; sessionId: SessionId; event: SessionEvent; view?: ToolEventView }
   | { type: 'session/subscribed'; sessionId: SessionId; lastSeq: number }
+  | { type: 'session/title'; sessionId: SessionId; title: string; eventSeq: number; updatedAt: number }
   | { type: 'approval/requested'; sessionId: SessionId; approvalId: ApprovalRequestId; toolName: string; callId?: CallId; reason?: string }
   | { type: 'approval/resolved'; sessionId: SessionId; approvalId: ApprovalRequestId; outcome: ApprovalOutcome }
   | { type: 'question/requested'; sessionId: SessionId; questions: AskUserQuestionItem[] }

packages/host/apiproxy/tests/rpc-schemas.spec.ts

@@ -124,6 +124,7 @@ describe('events frame schemas', () => {
     const frames = [
       { type: 'session/event', sessionId: 's', event: { type: 't', seq: 0, time: 1, data: null } },
       { type: 'session/subscribed', sessionId: 's', lastSeq: -1 },
+      { type: 'session/title', sessionId: 's', title: 'Durable title', eventSeq: 2, updatedAt: 3 },
       { type: 'approval/requested', sessionId: 's', approvalId: 'a', toolName: 'bash', callId: 'c', reason: 'r' },
       { type: 'approval/resolved', sessionId: 's', approvalId: 'a', outcome: 'allowed-once' },
       { type: 'question/requested', sessionId: 's', questions: [{ id: 'q', question: 'Q?', options: [{ label: 'L' }], multiSelect: true }] },
@@ -132,6 +133,13 @@ describe('events frame schemas', () => {
     ]
     for (const frame of frames) expect(muxFrameSchema.parse(frame)).toMatchObject({ type: frame.type })
     expect(() => muxFrameSchema.parse({ type: 'unknown/frame' })).toThrow()
+    for (const invalid of [
+      { type: 'session/title', sessionId: 's', title: '', eventSeq: 0, updatedAt: 1 },
+      { type: 'session/title', sessionId: 's', title: 'x', eventSeq: -1, updatedAt: 1 },
+      { type: 'session/title', sessionId: 's', title: 'x', eventSeq: 0.5, updatedAt: 1 },
+      { type: 'session/title', sessionId: 's', title: 'x', eventSeq: 0, updatedAt: 'now' },
+      { type: 'session/title', sessionId: 's', title: 'x', eventSeq: 0, updatedAt: Number.NaN },
+    ]) expect(() => muxFrameSchema.parse(invalid)).toThrow()
     expect(askUserQuestionItemSchema.parse({ id: 'q', question: 'Q?' }).id).toBe('q')
   })
 

packages/host/runtime/README.md

@@ -1,6 +1,6 @@
 # @deepseek-ai/dsh-host-runtime
 
-Host runtime assembly for `dsh`: `bootHost` composes the core plugin spine (LLM service + DeepSeek adapter, sessions with JSONL persistence, system prompt, tools, agents, agent loop, workspace instructions, local bash, and the provider-neutral user-interaction service), `createApiProxy` implements the [`dsh-host-apiproxy`](../apiproxy/README.md) contract over that composition, and `startHost` is the one-step shell seam returning `{ api, handler, defaults, ctx, dispose }`.
+Host runtime assembly for `dsh`: `bootHost` composes the core plugin spine (LLM service + DeepSeek adapter, sessions with JSONL persistence and immediate fallback titles, optional first-message model summaries, system prompt, tools, agents, agent loop, workspace instructions, local bash, and the provider-neutral user-interaction service), `createApiProxy` implements the [`dsh-host-apiproxy`](../apiproxy/README.md) contract over that composition, and `startHost` is the one-step shell seam returning `{ api, handler, defaults, ctx, dispose }`.
 
 Which plugins mount and with what defaults is decided only here — shells must not `ctx.plugin` to alter the assembly. `RunningHost.ctx` is a formal seam with exactly two sanctioned uses: mounting protocol front-door plugins (e.g. a future `dsh acp`) and headless session-event subscription; consuming clients must not bypass `api` through it.
 
@@ -12,6 +12,9 @@ Which plugins mount and with what defaults is decided only here — shells must
 | `workspaceContext` | (required) | [`AGENTS.md`/`CLAUDE.md` loader](../../context/workspace-context/README.md) config with an explicit `maxBytes`, or `false` to disable it. |
 | `provider` | `'deepseek'` | Default provider route injected as agentOptions on create/resume and reported by `host.describe`. |
 | `model` | `'deepseek-v4-flash'` | Default model id, same single source as `provider`. |
+| `cwd` | `process.cwd()` | Default project directory for a session whose create request omits `cwd`. |
+| `sessionTitle` | 5 words / 40 fallback bytes / 80 accepted bytes | Deterministic fallback and accepted-title limits. |
+| `sessionTitleLlm` | disabled | `true` enables the 5-word / 10-CJK-character, 4,096-input-byte, 64-output-token, 60-second first-message policy; an explicit config overrides it. An omitted route inherits the logged main-request provider and model. |
 
 ## ApiProxy implementation notes
 
@@ -19,11 +22,11 @@ Unary methods take the narrow `RpcRequest<P>` and echo `request.rpcId`; a prompt
 
 ## Model Experience
 
-Indirectly, through the model-facing plugins bootHost mounts and the provider/model defaults injected into created and resumed agents. When `workspaceContext` is enabled, each agent-loop instance freezes the applicable workspace instructions into its logged request prefix; the owning package documents the exact [model-visible framing](../../context/workspace-context/README.md#prompt-shape).
+Indirectly, through the non-blocking first-message title request owned by [`dsh-session-title-llm`](../../session-title/session-title-llm/README.md) when `sessionTitleLlm` is enabled, the provider/model defaults injected into created and resumed agents, the other model-facing plugins `bootHost` mounts, and the logged [workspace-instruction prefix](../../context/workspace-context/README.md#prompt-shape) when `workspaceContext` is enabled.
 
 #### KV Cache effect
 
-No direct invalidation; the mounted model-facing plugins own their request-prefix changes.
+No main-request invalidation; when enabled, the auxiliary title request has its own cache behavior and leaves the conversation prefix unchanged.
 
 ## Known Limitations and Deferred Work
 

packages/host/runtime/package.json

@@ -50,6 +50,8 @@
     "@deepseek-ai/dsh-session": "workspace:^",
     "@deepseek-ai/dsh-session-persistence": "workspace:^",
     "@deepseek-ai/dsh-session-persistence-jsonl": "workspace:^",
+    "@deepseek-ai/dsh-session-title": "workspace:^",
+    "@deepseek-ai/dsh-session-title-first-message-llm": "workspace:^",
     "@deepseek-ai/dsh-skill": "workspace:^",
     "@deepseek-ai/dsh-skill-local": "workspace:^",
     "@deepseek-ai/dsh-spill-local": "workspace:^",

packages/host/runtime/src/api-proxy.ts

@@ -10,6 +10,7 @@ import type { Agent, AgentStatus } from '@deepseek-ai/dsh-agent'
 import type { ContentBlock, MessageSource } from '@deepseek-ai/dsh-llm'
 import type { JsonValue, Session, SessionEvent, SessionHeader, SessionId } from '@deepseek-ai/dsh-session'
 import type { SessionPersistence } from '@deepseek-ai/dsh-session-persistence'
+import { foldSessionTitle } from '@deepseek-ai/dsh-session-title'
 import type {
   ApiProxy, HistoryEntry, HostFrame, MuxFrame, QuestionResponsePayload, SessionSummary, ToolEventView,
 } from '@deepseek-ai/dsh-host-apiproxy/api'
@@ -109,6 +110,28 @@ function frame<F>(payload: F): RpcRequest<F> {
   return { rpcId: RpcId(randomUUID()), payload }
 }
 
+type SessionTitleFrame = Extract<MuxFrame, { type: 'session/title' }>
+
+/** Project the latest durable title without exposing title-generation policy. */
+function titleFrame(session: Session): SessionTitleFrame | undefined {
+  const title = foldSessionTitle(session.events)
+  if (title === undefined) return undefined
+  return {
+    type: 'session/title',
+    sessionId: session.id,
+    title: title.title,
+    eventSeq: title.eventSeq,
+    updatedAt: title.updatedAt,
+  }
+}
+
+/** Queue the subscription baseline followed by its optional title snapshot. */
+function subscribeSession(queue: FrameQueue<RpcRequest<MuxFrame>>, session: Session): void {
+  queue.push(frame({ type: 'session/subscribed', sessionId: session.id, lastSeq: session.seq - 1 }))
+  const title = titleFrame(session)
+  if (title !== undefined) queue.push(frame(title))
+}
+
 /** SessionSummary projection for attached (in-memory) sessions. */
 function summarize(session: Session, running: boolean): SessionSummary {
   return {
@@ -455,7 +478,7 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
         const queue = new FrameQueue<RpcRequest<MuxFrame>>()
         muxQueues.add(queue)
         for (const session of ctx.sessions.list()) {
-          queue.push(frame({ type: 'session/subscribed', sessionId: session.id, lastSeq: session.seq - 1 }))
+          subscribeSession(queue, session)
         }
         for (const pending of pendingQuestions.values()) {
           queue.push({
@@ -487,9 +510,13 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
             const view = viewFor(ctx, event, callId =>
               openCalls.get(session.id)?.get(callId) ?? backscanArgs(session.events, callId))
             queue.push(frame({ type: 'session/event', sessionId: session.id, event, ...view === undefined ? {} : { view } }))
+            if (event.type === 'session/title') {
+              // The accepted raw event is already in session.events, so the fold must find it.
+              queue.push(frame(titleFrame(session) as SessionTitleFrame))
+            }
           }),
           ctx.on('session/created', (session: Session) => {
-            queue.push(frame({ type: 'session/subscribed', sessionId: session.id, lastSeq: session.seq - 1 }))
+            subscribeSession(queue, session)
           }),
           ctx.on('session/disposed', (session: Session) => {
             openCalls.delete(session.id)

packages/host/runtime/src/boot.ts

@@ -8,6 +8,9 @@ import { Context } from 'cordis'
 import Timer from '@cordisjs/plugin-timer'
 import LlmService from '@deepseek-ai/dsh-llm'
 import SessionStore from '@deepseek-ai/dsh-session'
+import SessionTitleService, { type Config as SessionTitleConfig } from '@deepseek-ai/dsh-session-title'
+import * as SessionTitleFirstMessageLlm from '@deepseek-ai/dsh-session-title-first-message-llm'
+import type { Config as SessionTitleLlmConfig } from '@deepseek-ai/dsh-session-title-first-message-llm'
 import SystemPrompt from '@deepseek-ai/dsh-system-prompt'
 import ToolRegistry from '@deepseek-ai/dsh-tools'
 import AgentRegistry from '@deepseek-ai/dsh-agent'
@@ -40,6 +43,22 @@ import SpillLocal from '@deepseek-ai/dsh-spill-local'
 import * as spillPolicy from '@deepseek-ai/dsh-spill-policy'
 import UserInteractionService from '@deepseek-ai/dsh-user-interaction'
 
+/** Default deterministic title policy for sessions created through the host. */
+const DEFAULT_SESSION_TITLE_CONFIG: SessionTitleConfig = {
+  fallbackMaxWords: 5,
+  fallbackMaxBytes: 40,
+  maxTitleBytes: 80,
+}
+
+/** Default first-message model-title policy for sessions created through the host. */
+const DEFAULT_SESSION_TITLE_LLM_CONFIG: SessionTitleLlmConfig = {
+  targetWords: 5,
+  targetCjkCharacters: 10,
+  maxInputBytes: 4_096,
+  maxOutputTokens: 64,
+  timeoutMs: 60_000,
+}
+
 /** Options for bootHost — the assembly-layer composition knobs. */
 export interface BootHostOptions {
   /** Root directory for JSONL session persistence. */
@@ -50,6 +69,10 @@ export interface BootHostOptions {
   provider?: string
   /** Default model id (defaults to 'deepseek-v4-flash', matching the demos). */
   model?: string
+  /** Deterministic fallback-title limits. */
+  sessionTitle?: SessionTitleConfig
+  /** Opt-in first-message model-title policy; `true` selects host defaults and an explicit config overrides them. */
+  sessionTitleLlm?: true | SessionTitleLlmConfig
   /**
    * Default project directory for sessions created without an explicit cwd
    * (defaults to the host process working directory). A session's cwd is its
@@ -93,6 +116,13 @@ export async function bootHost(options: BootHostOptions): Promise<HostHandle> {
   await ctx.plugin(Timer)
   await ctx.plugin(LlmService)
   await ctx.plugin(SessionStore)
+  await ctx.plugin(SessionTitleService, options.sessionTitle ?? DEFAULT_SESSION_TITLE_CONFIG)
+  if (options.sessionTitleLlm !== undefined) {
+    await ctx.plugin(
+      SessionTitleFirstMessageLlm,
+      options.sessionTitleLlm === true ? DEFAULT_SESSION_TITLE_LLM_CONFIG : options.sessionTitleLlm,
+    )
+  }
   await ctx.plugin(SystemPrompt, { persona: '' })
   await ctx.plugin(ToolRegistry)
   await ctx.plugin(UserInteractionService)

packages/host/runtime/tests/host-runtime.spec.ts

@@ -8,6 +8,8 @@ import { agentEvents } from '@deepseek-ai/dsh-agent'
 import type { GenerateOptions, StreamChunk } from '@deepseek-ai/dsh-llm'
 import { LlmAdapter } from '@deepseek-ai/dsh-llm'
 import type { SessionId } from '@deepseek-ai/dsh-session'
+import type { Config as SessionTitleConfig } from '@deepseek-ai/dsh-session-title'
+import type { Config as SessionTitleLlmConfig } from '@deepseek-ai/dsh-session-title-first-message-llm'
 import type { HostFrame, MuxFrame } from '@deepseek-ai/dsh-host-apiproxy/api'
 import type { RpcRequest, RpcResponse } from '@deepseek-ai/dsh-host-apiproxy/api/rpc'
 import { RpcId } from '@deepseek-ai/dsh-host-apiproxy/api/rpc'
@@ -22,6 +24,10 @@ class ScriptedAdapter extends LlmAdapter {
   }
 
   async * stream(options: GenerateOptions): AsyncIterable<StreamChunk> {
+    if ((options.tools?.length ?? 0) === 0) {
+      yield * textResponse('Durable append-only session titles')
+      return
+    }
     this.requests.push(options)
     const entry = this.script.shift()
     if (!entry) throw new Error('ScriptedAdapter: script exhausted')
@@ -68,6 +74,21 @@ function expectOk<T>(response: RpcResponse<T>): T {
   return response.result.value
 }
 
+async function nextMux(iterator: AsyncIterator<RpcRequest<MuxFrame>>): Promise<RpcRequest<MuxFrame>> {
+  const next = await iterator.next()
+  if (next.done === true) throw new Error('mux ended before the expected frame')
+  return next.value
+}
+
+/** Durably append a title event without mounting title-generation policy. */
+function appendTitle(ctx: Context, agent: Agent, title: string) {
+  return ctx.sessions.appendOutOfBand(agent.session, 'session/title', {
+    title,
+    messageSeqs: [1],
+    source: { kind: 'fallback' },
+  }, { kind: 'session-title' })
+}
+
 let host: RunningHost | undefined
 
 beforeEach(() => {
@@ -80,13 +101,19 @@ afterEach(async () => {
   vi.unstubAllEnvs()
 })
 
-async function boot(script: (StreamChunk[] | 'hang')[] = []): Promise<RunningHost> {
+async function boot(
+  script: (StreamChunk[] | 'hang')[] = [],
+  sessionTitle?: SessionTitleConfig,
+  sessionTitleLlm?: true | SessionTitleLlmConfig,
+): Promise<RunningHost> {
   host = await startHost({
     boot: {
       persistenceRoot: mkdtempSync(join(tmpdir(), 'dsh-host-runtime-')),
       workspaceContext: false,
       provider: 'scripted',
       model: 'test-model',
+      ...(sessionTitle === undefined ? {} : { sessionTitle }),
+      ...(sessionTitleLlm === undefined ? {} : { sessionTitleLlm }),
     },
   })
   host.ctx.llm.registerAdapter(['scripted'], new ScriptedAdapter(script))
@@ -161,6 +188,23 @@ describe('bootHost / startHost', () => {
     expect(requestText).toContain('Instructions from: AGENTS.md')
     expect(requestText).toContain('host-workspace-context-probe')
   })
+
+  it('keeps model title generation disabled when sessionTitleLlm is omitted', async () => {
+    const running = await boot([textResponse('pong')])
+    const { api, ctx } = running
+    const { sessionId } = expectOk(await api.sessions.create(request({})))
+    const agent = ctx.agents.get(sessionId) as Agent
+    const idle = waitForIdle(ctx, agent)
+    expectOk(await api.sessions.prompt(request({
+      sessionId,
+      mode: 'queue' as const,
+      content: [{ type: 'text' as const, text: 'Explain durable session titles.' }],
+    })))
+    await idle
+
+    expect((await ctx.sessionTitle.refresh(agent.session))?.source).toEqual({ kind: 'fallback' })
+    expect(agent.session.events.some(event => event.type === 'session/title-llm-request')).toBe(false)
+  })
 })
 
 describe('host.describe', () => {
@@ -190,6 +234,94 @@ describe('sessions.create / list', () => {
 })
 
 describe('sessions.prompt / cancel', () => {
+  it.each([
+    { name: 'host default', config: true, target: '5 words', maxTokens: 64 },
+    {
+      name: 'configured policy',
+      config: {
+        targetWords: 3,
+        targetCjkCharacters: 8,
+        maxInputBytes: 2_048,
+        maxOutputTokens: 24,
+        timeoutMs: 2_000,
+      },
+      target: '3 words',
+      maxTokens: 24,
+    },
+  ] satisfies {
+    name: string
+    config: true | SessionTitleLlmConfig
+    target: string
+    maxTokens: number
+  }[])('replaces the fallback with a model-backed first-message title using the $name', async ({ config, target, maxTokens }) => {
+    const modelTitle = 'Durable append-only session titles'
+    const running = await boot([textResponse('pong')], undefined, config)
+    const { api, ctx } = running
+    const { sessionId } = expectOk(await api.sessions.create(request({})))
+    const agent = ctx.agents.get(sessionId) as Agent
+    const idle = waitForIdle(ctx, agent)
+    expectOk(await api.sessions.prompt(request({
+      sessionId,
+      mode: 'queue' as const,
+      content: [{ type: 'text' as const, text: 'Explain why append-only logs make session titles durable.' }],
+    })))
+    await idle
+
+    await vi.waitFor(() => {
+      expect(agent.session.events.filter(event => event.type === 'session/title').map(event => event.data))
+        .toEqual([
+          {
+            title: 'Explain why append-only logs make',
+            messageSeqs: [1],
+            source: { kind: 'fallback' },
+          },
+          {
+            title: modelTitle,
+            messageSeqs: [1],
+            source: {
+              kind: 'provider',
+              provider: 'session-title-first-message-llm',
+              model: { provider: 'scripted', model: 'test-model' },
+            },
+          },
+        ])
+    })
+    const titleRequest = agent.session.events.find(event => event.type === 'session/title-llm-request')
+    expect(titleRequest?.data.system).toContain(target)
+    expect(titleRequest?.data.maxTokens).toBe(maxTokens)
+  })
+
+  it.each([
+    { name: 'host default', config: undefined, expected: 'Show the Web UI durable' },
+    {
+      name: 'configured limit',
+      config: { fallbackMaxWords: 2, fallbackMaxBytes: 40, maxTitleBytes: 80 },
+      expected: 'Show the',
+    },
+  ] satisfies { name: string; config: SessionTitleConfig | undefined; expected: string }[])(
+    'logs a durable fallback title with the $name',
+    async ({ config, expected }) => {
+      const running = await boot([textResponse('pong')], config)
+      const { api, ctx } = running
+      const { sessionId } = expectOk(await api.sessions.create(request({})))
+      const agent = ctx.agents.get(sessionId) as Agent
+      const idle = waitForIdle(ctx, agent)
+      expectOk(await api.sessions.prompt(request({
+        sessionId,
+        mode: 'queue' as const,
+        content: [{ type: 'text' as const, text: 'Show the Web UI durable session title' }],
+      })))
+      await idle
+
+      const title = agent.session.events.find(event => event.type === 'session/title')
+      expect(title?.data).toEqual({
+        title: expected,
+        messageSeqs: [1],
+        source: { kind: 'fallback' },
+      })
+    },
+  )
+
   it('queues a prompt whose rpcId rides into user/message, then the reply lands', async () => {
     const running = await boot([textResponse('pong')])
     const { api, ctx } = running
@@ -261,6 +393,7 @@ describe('sessions.history', () => {
     const idle = waitForIdle(first.ctx, agent)
     agent.send([{ type: 'text', text: 'save me' }])
     await idle
+    const titleEvent = await appendTitle(first.ctx, agent, 'Persisted title')
     await first.dispose()
 
     host = await startHost({
@@ -268,6 +401,8 @@ describe('sessions.history', () => {
     })
     host.ctx.llm.registerAdapter(['scripted'], new ScriptedAdapter([]))
     expect(host.ctx.agents.get(sessionId)).toBeUndefined()
+    const abort = new AbortController()
+    const mux = host.api.events.mux(request({}), abort.signal)[Symbol.asyncIterator]()
     const [a, b] = await Promise.all([
       host.api.sessions.history(request({ sessionId })),
       host.api.sessions.history(request({ sessionId })),
@@ -278,6 +413,11 @@ describe('sessions.history', () => {
     }
     expect(host.ctx.agents.get(sessionId)).toBeDefined()
     expect(host.ctx.agents.list()).toHaveLength(1)
+    expect((await nextMux(mux)).payload).toMatchObject({ type: 'session/subscribed', sessionId })
+    expect((await nextMux(mux)).payload).toEqual(expect.objectContaining({
+      type: 'session/title', sessionId, title: 'Persisted title', eventSeq: titleEvent.seq,
+    }))
+    abort.abort()
   })
 
   it('errors session-not-found when resume fails, deduplicating concurrent resumes', async () => {
@@ -385,6 +525,43 @@ describe('events streams', () => {
     expect((await stream.next()).done).toBe(true)
   })
 
+  it('mux: projects durable titles after open baselines and immediately after live raw events', async () => {
+    const running = await boot()
+    const { api, ctx } = running
+    const { sessionId } = expectOk(await api.sessions.create(request({})))
+    const agent = ctx.agents.get(sessionId) as Agent
+    const initial = await appendTitle(ctx, agent, 'Initial title')
+
+    const ac = new AbortController()
+    const stream = api.events.mux(request({}), ac.signal)[Symbol.asyncIterator]()
+    expect((await nextMux(stream)).payload).toMatchObject({ type: 'session/subscribed', sessionId })
+    expect((await nextMux(stream)).payload).toEqual(expect.objectContaining({
+      type: 'session/title', sessionId, title: 'Initial title', eventSeq: initial.seq, updatedAt: initial.time,
+    }))
+
+    const revised = await appendTitle(ctx, agent, 'Revised title')
+    let raw: RpcRequest<MuxFrame>
+    do raw = await nextMux(stream)
+    while (!(raw.payload.type === 'session/event' && raw.payload.event.type === 'session/title'))
+    expect(raw.payload).toMatchObject({ type: 'session/event', sessionId, event: { seq: revised.seq } })
+    expect((await nextMux(stream)).payload).toEqual(expect.objectContaining({
+      type: 'session/title', sessionId, title: 'Revised title', eventSeq: revised.seq, updatedAt: revised.time,
+    }))
+    ac.abort()
+  })
+
+  it('mux: emits no title control for untitled subscriptions', async () => {
+    const { api } = await boot()
+    const first = expectOk(await api.sessions.create(request({}))).sessionId
+    const ac = new AbortController()
+    const stream = api.events.mux(request({}), ac.signal)[Symbol.asyncIterator]()
+    expect((await nextMux(stream)).payload).toMatchObject({ type: 'session/subscribed', sessionId: first })
+
+    const second = expectOk(await api.sessions.create(request({}))).sessionId
+    expect((await nextMux(stream)).payload).toMatchObject({ type: 'session/subscribed', sessionId: second })
+    ac.abort()
+  })
+
   it('host: session lifecycle, status flips (disposed suppressed), and agent errors', async () => {
     const running = await boot([textResponse('x')])
     const { api, ctx } = running

packages/host/runtime/tsconfig.json

@@ -23,6 +23,12 @@
     {
       "path": "../../core/session"
     },
+    {
+      "path": "../../session-title/session-title"
+    },
+    {
+      "path": "../../session-title/session-title-first-message-llm"
+    },
     {
       "path": "../../core/system-prompt"
     },

packages/llm/llm-deepseek/README.md

@@ -32,7 +32,7 @@ The plugin registers the single provider route `deepseek`. A request selects it
 
 `reasoningEffort` is **omitted by default** — when unset, the `reasoning_effort` wire field is not sent and the server applies its own default for the model. The only accepted values are `high` and `max` (DeepSeek's official effort levels). It is meaningful only with thinking enabled (the provider default).
 
-`thinking`/`reasoningEffort` are adapter-level request defaults serialized as the official top-level `thinking: {type}` / `reasoning_effort` wire fields. They live in adapter config (not `GenerateOptions`) to keep the core vocabulary provider-neutral.
+`thinking`/`reasoningEffort` are adapter-level request defaults serialized as the official top-level `thinking: {type}` / `reasoning_effort` wire fields. They live in adapter config (not `GenerateOptions`) to keep the core vocabulary provider-neutral. A request with `GenerateOptions.purpose: 'session-title'` forces thinking disabled and omits `reasoning_effort`, reserving its bounded output for visible title text without changing conversation or compaction defaults.
 
 `streamIdleTimeoutMs` bounds each outstanding provider read, including the initial `fetch`, without counting time the consumer spends between chunks. One stable abort signal reaches the request and body reader for the whole call; expiry stops the transport and throws `LlmError('TIMEOUT')`, while an earlier caller abort throws `LlmError('ABORTED')`. The adapter makes exactly one provider request per `stream()` call; agent-level retry is a separate plugin policy.
 

packages/llm/llm-deepseek/src/serialize.ts

@@ -118,14 +118,18 @@ export function serializeRequest(options: GenerateOptions, defaults: RequestDefa
       parameters: tool.parameters,
     },
   }))
+  // A short title budget must produce visible text; conversation and
+  // compaction calls continue to inherit the adapter's thinking defaults.
+  const thinking = options.purpose === 'session-title' ? 'disabled' : defaults.thinking
+  const reasoningEffort = options.purpose === 'session-title' ? undefined : defaults.reasoningEffort
 
   return {
     model: options.model,
     messages,
     stream: true,
     stream_options: { include_usage: true },
-    ...defaults.thinking !== undefined ? { thinking: { type: defaults.thinking } } : {},
-    ...defaults.reasoningEffort !== undefined ? { reasoning_effort: defaults.reasoningEffort } : {},
+    ...thinking !== undefined ? { thinking: { type: thinking } } : {},
+    ...reasoningEffort !== undefined ? { reasoning_effort: reasoningEffort } : {},
     ...tools !== undefined && tools.length > 0 ? { tools } : {},
     ...options.temperature !== undefined ? { temperature: options.temperature } : {},
     ...options.maxTokens !== undefined ? { max_tokens: options.maxTokens } : {},

packages/llm/llm-deepseek/tests/serialize.spec.ts

@@ -180,6 +180,15 @@ describe('serializeRequest', () => {
     expect(wire.reasoning_effort).toBe('max')
   })
 
+  it('disables thinking for session-title requests without changing adapter defaults', () => {
+    const wire = serializeRequest(
+      request({ messages: history, purpose: 'session-title' }),
+      { thinking: 'enabled', reasoningEffort: 'max' },
+    )
+    expect(wire.thinking).toEqual({ type: 'disabled' })
+    expect(wire.reasoning_effort).toBeUndefined()
+  })
+
   it('omits thinking fields when unset (provider default applies)', () => {
     const wire = serializeRequest(request({ messages: history }))
     expect(wire.thinking).toBeUndefined()

packages/llm/llm/README.md

@@ -39,7 +39,7 @@ Streaming is a raw chunk protocol (`block-start`, `text-delta`, `reasoning-delta
 
 ### Call configuration (`call-config.ts`)
 
-`LlmCallConfig` is the provider + model + sampling scalars of one conversation's requests (`provider`, `model`, `temperature`, `maxTokens`, `stop` — each mapping 1:1 onto the same-named `GenerateOptions` field). It is per-conversation state recorded in the session log as part of the request header (see the dsh-session `request/header` events), never a silently-adjustable per-call knob: the `agent/request` waterfall proposes a replacement and the loop logs a real change. `callConfigEquals(a, b)` is the field-wise real-change detector; `deepFreeze(value)` is the ownership helper the loop applies to every built request before dispatch (`llm/stream` listeners and adapters read, never rewrite). `markAgentLoopRequest()` gives that exact object process-local loop provenance, and `isAgentLoopRequest()` lets observers distinguish it from independently logged auxiliary calls that may also be frozen and session-associated.
+`LlmCallConfig` is the provider + model + sampling scalars of one conversation's requests (`provider`, `model`, `temperature`, `maxTokens`, `stop` — each mapping 1:1 onto the same-named `GenerateOptions` field). It is per-conversation state recorded in the session log as part of the request header (see the dsh-session `request/header` events), never a silently-adjustable per-call knob: the `agent/request` waterfall proposes a replacement and the loop logs a real change. `callConfigEquals(a, b)` is the field-wise real-change detector; `deepFreeze(value)` is the ownership helper the loop applies to every built request before dispatch (`llm/stream` listeners and adapters read, never rewrite). `markAgentLoopRequest()` gives that exact object process-local loop provenance, and `isAgentLoopRequest()` lets observers distinguish it from independently logged auxiliary calls that may also be frozen and session-associated. `GenerateOptions.purpose` classifies logged auxiliary compaction and session-title calls so adapters can apply purpose-specific transport policy without changing ordinary conversation requests.
 
 ### App attribution (`attribution.ts`)
 

packages/llm/llm/src/types.ts

@@ -228,8 +228,8 @@ export interface GenerateOptions {
   sessionId?: Branded<'SessionId'>
   /**
    * Provider-neutral classification for an auxiliary model call. Adapters may
-   * map the purpose to model-hidden transport metadata. Ordinary conversation
-   * requests leave it unset.
+   * map the purpose to model-hidden transport metadata or purpose-specific
+   * generation policy. Ordinary conversation requests leave it unset.
    */
-  purpose?: 'compaction'
+  purpose?: 'compaction' | 'session-title'
 }

packages/session-title/session-title-llm/README.md

@@ -8,7 +8,7 @@ This package is a library, not a Cordis plugin. The provider plugins call `regis
 
 `provider` and `model` overrides are optional but must be supplied together as non-empty strings. Without that pair, the helper uses the exact provider/model route captured from the current session's logged `request/header`; an explicit refresh before any route exists therefore needs overrides. The helper measures the final JSON-framed user prompt, including seq fields, wrappers, and JSON escaping, against `maxInputBytes` before logging or dispatch instead of truncating it. Timeout and caller cancellation are rechecked while consuming the stream and after it completes, so a late successful result cannot be accepted even if an interceptor or adapter ignores abort. Malformed or empty output, tool calls, and non-stop finish reasons also reject; the session-title service decides whether that rejection is an automatic warning or an explicit caller failure.
 
-After route and input validation, the helper appends a log-only `session/title-llm-request` event before model dispatch. It contains the title-provider id, exact source seqs, route, system prompt, message list, and output-token cap used by the call. The append shares the title capability's per-session settlement queue, so a superseding request cannot collide with an earlier fallback, request record, or accepted-title flush. The dispatched envelope is deep-frozen to keep interceptors aligned with that record but deliberately lacks dsh-agent-loop's process-local request identity, so loop-only reconstruction observers do not compare it with the conversation header. A later model failure leaves that request record intact; validation failures that never become dispatchable requests do not create one. The event stays outside derived model history.
+After route and input validation, the helper appends a log-only `session/title-llm-request` event before model dispatch. It contains the title-provider id, exact source seqs, route, system prompt, message list, and output-token cap used by the call. The append shares the title capability's per-session settlement queue, so a superseding request cannot collide with an earlier fallback, request record, or accepted-title flush. The dispatched envelope is deep-frozen, carries `purpose: 'session-title'`, and deliberately lacks dsh-agent-loop's process-local request identity. Interceptors stay aligned with the record while loop-only reconstruction observers do not compare it with the conversation header. The DeepSeek adapter maps that purpose to thinking-disabled so the small output budget is reserved for visible title text; other adapters own their purpose-specific behavior. A later model failure leaves the request record intact; validation failures that never become dispatchable requests do not create one. The event stays outside derived model history.
 
 ## Configuration
 
@@ -33,7 +33,7 @@ The title model receives a fixed system instruction to return one concise unador
 
 #### Token effect
 
-The auxiliary request consumes tokens according to selected input size and `maxOutputTokens`. It is separate from the main agent request and does not add title text or framing to agent history.
+The auxiliary request consumes tokens according to selected input size and `maxOutputTokens`. It is separate from the main agent request and does not add title text or framing to agent history. DeepSeek title calls disable thinking; the main conversation retains its configured thinking mode.
 
 #### KV Cache effect
 

packages/session-title/session-title-llm/src/index.ts

@@ -261,6 +261,7 @@ export async function generateSessionTitleWithLlm(
     system,
     maxTokens: config.maxOutputTokens,
     sessionId: request.session.id,
+    purpose: 'session-title',
     signal: callDeadline.signal,
   })
   await appendSessionTitleOutOfBand(ctx, request.session, 'session/title-llm-request', {

packages/session-title/session-title-llm/tests/llm.spec.ts

@@ -156,6 +156,7 @@ describe('generateSessionTitleWithLlm', () => {
       model: 'current-model',
       maxTokens: 32,
       sessionId: providerRequest.session.id,
+      purpose: 'session-title',
     })
     expect(options.system).toContain('5 words')
     expect(options.system).toContain('10 CJK characters')