fix(native-chat): recover from 'No transcript found' race on a just-created session

Claude Code lazily flushes a new session's .jsonl, so the first transcript
read/tail can race the first write. When the file doesn't exist yet the reader
and cache returned a hard {error}, the renderer settled into phase 'error' with
no retry, and the live watcher no-op'd forever — so a session that is actually
alive stuck on 'No transcript found'.

Layered, additive fix (zero-regression):
- reader/cache: mark a missing file as a retryable notFound (null-resolve and
  ENOENT-after-resolve); genuine non-ENOENT read/parse errors stay hard errors.
  A notFound is never cached, so a later real read is not masked by a cached miss.
- renderer hook: on notFound, stay in 'loading' and retry readSession with a
  bounded exponential backoff (1/2/4/8s, cap 10s); timer cleared on teardown.
- transcript-watch: install a backing-off resolve-poll (1s->10s cap) so a
  not-yet-created file is picked up when it appears; blank-sessionId guard and
  race-safe unsubscribe (no watcher/timer leak).

Fixes #8401

Co-authored-by: Orca <help@stably.ai>

src/main/native-chat/transcript-not-found.test.ts

@@ -0,0 +1,111 @@
+import { mkdir, mkdtemp, rm, writeFile } from 'node:fs/promises'
+import { tmpdir } from 'node:os'
+import { join } from 'node:path'
+import { afterEach, beforeEach, describe, expect, it } from 'vitest'
+import { readNativeChatTranscript } from './transcript-reader'
+import {
+  clearNativeChatTranscriptCache,
+  readNativeChatTranscriptCached
+} from './transcript-read-cache'
+
+// These cover the "No transcript found on a just-created session that is actually
+// alive" race (#8401): Claude Code lazily flushes the first turn, so the session
+// .jsonl briefly does not exist. A missing file must surface as a RETRYABLE
+// notFound, never a hard error, and a notFound must not be cached (else the later
+// real read is masked by the cached miss).
+
+let tempRoots: string[] = []
+
+beforeEach(() => {
+  clearNativeChatTranscriptCache()
+  tempRoots = []
+})
+
+afterEach(async () => {
+  await Promise.all(tempRoots.map((root) => rm(root, { recursive: true, force: true })))
+  tempRoots = []
+})
+
+function jsonLines(records: unknown[]): string {
+  return records.map((record) => JSON.stringify(record)).join('\n')
+}
+
+async function emptyProjectsDir(): Promise<string> {
+  const root = await mkdtemp(join(tmpdir(), 'orca-native-chat-notfound-'))
+  tempRoots.push(root)
+  return join(root, 'projects')
+}
+
+describe('readNativeChatTranscript — notFound vs hard error', () => {
+  it('flags an unresolvable session as notFound (retryable), not a hard error', async () => {
+    const result = await readNativeChatTranscript('claude', 'not-flushed-yet', {
+      claudeProjectsDir: await emptyProjectsDir()
+    })
+    expect('error' in result).toBe(true)
+    expect('notFound' in result && result.notFound).toBe(true)
+  })
+
+  it('flags an ENOENT after resolve (file vanished/not-yet-there) as notFound', async () => {
+    const result = await readNativeChatTranscript('claude', 'sess', {
+      filePath: join(tmpdir(), 'orca-native-chat-8401-does-not-exist.jsonl')
+    })
+    expect('error' in result).toBe(true)
+    expect('notFound' in result && result.notFound).toBe(true)
+  })
+
+  it('keeps a genuine non-ENOENT read error a HARD error (no notFound)', async () => {
+    // A directory path makes createReadStream fail with EISDIR — a real failure,
+    // not a not-yet-flushed file, so it must stay a hard error the UI surfaces.
+    const dir = await mkdtemp(join(tmpdir(), 'orca-native-chat-eisdir-'))
+    tempRoots.push(dir)
+    const result = await readNativeChatTranscript('claude', 'sess', { filePath: dir })
+    expect('error' in result).toBe(true)
+    expect('notFound' in result && result.notFound).toBeFalsy()
+  })
+})
+
+describe('readNativeChatTranscriptCached — notFound is retryable and never masks a real read', () => {
+  it('returns a notFound (not a hard error) for a not-yet-created session file', async () => {
+    const root = await mkdtemp(join(tmpdir(), 'orca-native-chat-notfound-cache-'))
+    tempRoots.push(root)
+    process.env.HOME = root
+    const result = await readNativeChatTranscriptCached('claude', 'absent-session')
+    expect('error' in result).toBe(true)
+    expect('notFound' in result && result.notFound).toBe(true)
+  })
+
+  it('does not cache the notFound miss: a later read after the file appears succeeds', async () => {
+    const root = await mkdtemp(join(tmpdir(), 'orca-native-chat-notfound-appears-'))
+    tempRoots.push(root)
+    process.env.HOME = root
+    const sessionId = 'lazy-flush'
+
+    // First read races the lazy first flush: the file does not exist yet.
+    const first = await readNativeChatTranscriptCached('claude', sessionId)
+    expect('notFound' in first && first.notFound).toBe(true)
+
+    // Claude Code flushes the transcript moments later.
+    const projectDir = join(root, '.claude', 'projects', '-repo')
+    await mkdir(projectDir, { recursive: true })
+    await writeFile(
+      join(projectDir, `${sessionId}.jsonl`),
+      jsonLines([
+        {
+          type: 'user',
+          uuid: 'u-0',
+          timestamp: '2026-06-01T10:00:00.000Z',
+          message: { role: 'user', content: 'hello there' }
+        }
+      ])
+    )
+
+    // The second read must re-resolve and read the now-present file, not serve a
+    // cached miss (which would keep the pane stuck on "No transcript found").
+    const second = await readNativeChatTranscriptCached('claude', sessionId)
+    expect('messages' in second).toBe(true)
+    if (!('messages' in second)) {
+      return
+    }
+    expect(second.messages).toHaveLength(1)
+  })
+})

src/main/native-chat/transcript-read-cache.ts

@@ -91,7 +91,9 @@ export async function readNativeChatTranscriptCached(
 ): Promise<ReadTranscriptResult> {
   const filePath = await resolveSessionFilePath(agent, sessionId, { transcriptPath })
   if (!filePath) {
-    return { error: `No transcript found for ${agent} session ${sessionId}` }
+    // Retryable miss (session .jsonl not flushed yet, #8401). Return BEFORE the
+    // cache write below so a later real read is never masked by a cached miss.
+    return { error: `No transcript found for ${agent} session ${sessionId}`, notFound: true }
   }
 
   const key = cacheKey(agent, filePath)
@@ -104,7 +106,10 @@ export async function readNativeChatTranscriptCached(
   }
 
   const result = await readNativeChatTranscript(agent, sessionId, { filePath })
-  if (Number.isFinite(mtimeMs)) {
+  // Never cache a notFound miss (an ENOENT after resolve): the file may appear
+  // moments later, and a cached miss would keep the pane stuck on "No transcript
+  // found" until the mtime changed. Genuine parses/errors cache as before.
+  if (Number.isFinite(mtimeMs) && !('notFound' in result && result.notFound)) {
     setCached(key, { result, mtimeMs, bytes })
   }
   return result

src/main/native-chat/transcript-reader.ts

@@ -9,7 +9,19 @@ import {
 } from './transcript-line-decoders'
 import { decodeTranscriptStream } from './transcript-stream-lines'
 
-export type ReadTranscriptResult = { messages: NativeChatMessage[] } | { error: string }
+export type ReadTranscriptResult =
+  | { messages: NativeChatMessage[] }
+  // `notFound` marks a RETRYABLE miss (the session .jsonl isn't flushed yet — see
+  // #8401), distinct from a hard read/parse error. Callers may retry a notFound
+  // and must not cache it; a plain `error` is surfaced to the user immediately.
+  | { error: string; notFound?: true }
+
+// Why: a not-yet-created (or momentarily-vanished) transcript file surfaces as
+// ENOENT once resolve returns a path. That's the lazy-flush race, not a real
+// failure, so it becomes a retryable notFound; every other error stays hard.
+function isFileNotFoundError(err: unknown): boolean {
+  return err instanceof Error && 'code' in err && (err as NodeJS.ErrnoException).code === 'ENOENT'
+}
 
 export type ReadTranscriptOptions = ResolveSessionFileOptions & {
   /** Resolve directly to this file, skipping path discovery (used by tests). */
@@ -30,7 +42,9 @@ export async function readNativeChatTranscript(
 ): Promise<ReadTranscriptResult> {
   const filePath = options.filePath ?? (await resolveSessionFilePath(agent, sessionId, options))
   if (!filePath) {
-    return { error: `No transcript found for ${agent} session ${sessionId}` }
+    // The file hasn't been flushed yet (or was resolved away). Retryable, not a
+    // hard error — the caller polls/backs off until the lazy first write lands.
+    return { error: `No transcript found for ${agent} session ${sessionId}`, notFound: true }
   }
   try {
     if (agent === 'claude') {
@@ -44,6 +58,9 @@ export async function readNativeChatTranscript(
     }
     return { error: `Unsupported agent for native chat transcript: ${agent}` }
   } catch (err) {
+    if (isFileNotFoundError(err)) {
+      return { error: errorMessage(err), notFound: true }
+    }
     return { error: errorMessage(err) }
   }
 }

src/main/native-chat/transcript-watch.test.ts

@@ -1,4 +1,4 @@
-import { appendFile, mkdtemp, rm, writeFile } from 'node:fs/promises'
+import { appendFile, mkdir, mkdtemp, rm, writeFile } from 'node:fs/promises'
 import { tmpdir } from 'node:os'
 import { join } from 'node:path'
 import { afterEach, beforeEach, describe, expect, it } from 'vitest'
@@ -236,4 +236,66 @@ describe('subscribeNativeChatTranscript', () => {
     // Must not throw.
     sub.unsubscribe()
   })
+
+  it('installs the watcher once a not-yet-created session file appears (#8401 poll)', async () => {
+    // The transcript file does not exist at subscribe time (Claude Code's lazy
+    // first flush). The resolve-poll must pick it up once the agent writes it,
+    // instead of leaving the pane's live tail permanently deaf.
+    const root = await mkdtemp(join(tmpdir(), 'orca-native-chat-poll-'))
+    tempRoots.push(root)
+    const projectsDir = join(root, 'projects')
+    const projectDir = join(projectsDir, '-repo')
+    await mkdir(projectDir, { recursive: true })
+    const before = getActiveNativeChatWatcherCount()
+    const seen: NativeChatMessage[] = []
+
+    const sub = await subscribeNativeChatTranscript({
+      agent: 'claude',
+      sessionId: 'lazy-flush',
+      claudeProjectsDir: projectsDir,
+      onAppend: (messages) => seen.push(...messages),
+      debounceMs: 5,
+      resolvePollMs: 15
+    })
+
+    // No file yet → no watcher installed, but the poll is running.
+    expect(getActiveNativeChatWatcherCount()).toBe(before)
+
+    const target = join(projectDir, 'lazy-flush.jsonl')
+    await writeFile(target, claudeLine('u-1', 'user', 'first'))
+    await waitFor(() => seen.some((m) => m.id === 'u-1'))
+    expect(getActiveNativeChatWatcherCount()).toBe(before + 1)
+
+    // A later append on the now-watched file is tailed incrementally.
+    await appendFile(target, claudeLine('a-1', 'assistant', 'reply'))
+    await waitFor(() => seen.some((m) => m.id === 'a-1'))
+
+    sub.unsubscribe()
+    expect(getActiveNativeChatWatcherCount()).toBe(before)
+  })
+
+  it('stops the resolve-poll on unsubscribe before the file appears (no leak)', async () => {
+    const root = await mkdtemp(join(tmpdir(), 'orca-native-chat-poll-cancel-'))
+    tempRoots.push(root)
+    const projectsDir = join(root, 'projects')
+    await mkdir(projectsDir, { recursive: true })
+    const before = getActiveNativeChatWatcherCount()
+
+    const sub = await subscribeNativeChatTranscript({
+      agent: 'claude',
+      sessionId: 'never-flushed',
+      claudeProjectsDir: projectsDir,
+      onAppend: () => {},
+      resolvePollMs: 10
+    })
+    // Tear down while still polling (file never created).
+    sub.unsubscribe()
+
+    // Even if the file appears later, the stopped poll installs no watcher.
+    const projectDir = join(projectsDir, '-repo')
+    await mkdir(projectDir, { recursive: true })
+    await writeFile(join(projectDir, 'never-flushed.jsonl'), claudeLine('u-1', 'user', 'x'))
+    await new Promise((resolve) => setTimeout(resolve, 40))
+    expect(getActiveNativeChatWatcherCount()).toBe(before)
+  })
 })

src/main/native-chat/transcript-watch.ts

@@ -29,6 +29,9 @@ export type SubscribeNativeChatTranscriptArgs = ResolveSessionFileOptions & {
   filePath?: string
   /** Coalesce window for rapid fs.watch events (ms). Defaults to 40ms. */
   debounceMs?: number
+  /** Re-resolve interval while the session file doesn't exist yet (ms).
+   *  Defaults to RESOLVE_POLL_MS; overridable so tests run fast. */
+  resolvePollMs?: number
 }
 
 export type NativeChatTranscriptSubscription = {
@@ -42,6 +45,17 @@ export type NativeChatTranscriptSubscription = {
 // mapping the full reader uses.
 const DEFAULT_DEBOUNCE_MS = 40
 
+// Why: a just-created session's .jsonl is written lazily — an agent can take
+// from a few seconds to minutes to flush its first line (#8401) — so resolve can
+// return null right after subscribe. Re-resolve on a backing-off interval until
+// the file appears, then install the watcher; otherwise a live pane opened before
+// the first flush would never tail. The backoff keeps a long wait cheap (a fixed
+// fast poll would repeat the directory walk hundreds of times). Only runs while
+// the file is missing; a non-blank sessionId is required (blank has nothing to
+// resolve).
+const RESOLVE_POLL_INITIAL_MS = 1000
+const RESOLVE_POLL_MAX_MS = 10_000
+
 // Why: process-wide count of live FSWatchers opened by this module. The U4 leak
 // test asserts this returns to zero after unsubscribe so a forgotten handle is
 // caught deterministically rather than relying on OS fd inspection.
@@ -125,13 +139,13 @@ async function readAppendedMessages(
 export async function subscribeNativeChatTranscript(
   args: SubscribeNativeChatTranscriptArgs
 ): Promise<NativeChatTranscriptSubscription> {
-  const { agent, sessionId, onAppend, debounceMs } = args
+  const { agent, sessionId, onAppend, debounceMs, resolvePollMs } = args
   const decode = lineDecoderForAgent(agent)
-  const filePath = args.filePath ?? (await resolveSessionFilePath(agent, sessionId, args))
+  const initialPath = args.filePath ?? (await resolveSessionFilePath(agent, sessionId, args))
 
-  if (!filePath || !decode) {
-    // Nothing watchable — return a no-op teardown so callers can unconditionally
-    // unsubscribe without null-checks.
+  if (!decode) {
+    // Unknown agent — nothing to decode. No-op teardown so callers can
+    // unconditionally unsubscribe without null-checks.
     return { unsubscribe: () => {} }
   }
 
@@ -145,11 +159,19 @@ export async function subscribeNativeChatTranscript(
   let reading = false
   let pendingReadRequested = false
   let debounceTimer: ReturnType<typeof setTimeout> | null = null
+  let resolvePollTimer: ReturnType<typeof setTimeout> | null = null
+  let watcher: FSWatcher | null = null
+  // The resolved path, set once the file exists (immediately, or via the poll).
+  let currentFilePath: string | null = initialPath
 
   async function drain(): Promise<void> {
     if (closed) {
       return
     }
+    const path = currentFilePath
+    if (path === null) {
+      return
+    }
     if (reading) {
       // A read is already in flight; mark that another pass is needed so rapid
       // successive appends coalesce without dropping the trailing one.
@@ -161,12 +183,12 @@ export async function subscribeNativeChatTranscript(
       do {
         pendingReadRequested = false
         try {
-          const currentSize = await fileSize(filePath!)
+          const currentSize = await fileSize(path)
           if (currentSize < offset) {
             // Rotation/replacement/truncation: re-read from the top.
             offset = 0
           }
-          const { messages, consumedTo } = await readAppendedMessages(filePath!, offset, decode!)
+          const { messages, consumedTo } = await readAppendedMessages(path, offset, decode!)
           offset = consumedTo
           if (!closed && messages.length > 0) {
             onAppend(messages)
@@ -196,19 +218,76 @@ export async function subscribeNativeChatTranscript(
     }, debounceMs ?? DEFAULT_DEBOUNCE_MS)
   }
 
-  let watcher: FSWatcher
-  try {
-    watcher = watch(filePath, scheduleDrain)
-  } catch {
-    // File vanished between resolve and watch — return a no-op teardown.
-    return { unsubscribe: () => {} }
+  function stopResolvePoll(): void {
+    if (resolvePollTimer) {
+      clearTimeout(resolvePollTimer)
+      resolvePollTimer = null
+    }
   }
-  activeWatcherCount++
 
-  // Why: on some platforms fs.watch can miss the very first append that lands
-  // between offset-seed and watcher install. Kick one debounced drain so a
-  // turn written immediately after subscribe is still picked up.
-  scheduleDrain()
+  // Install the fs watcher on a now-present file. Returns false when watch()
+  // throws (the file vanished again), so the poll caller keeps trying.
+  function installWatcher(path: string): boolean {
+    if (closed) {
+      return false
+    }
+    let installed: FSWatcher
+    try {
+      installed = watch(path, scheduleDrain)
+    } catch {
+      return false
+    }
+    watcher = installed
+    currentFilePath = path
+    activeWatcherCount++
+    // Why: on some platforms fs.watch can miss the very first append that lands
+    // between offset-seed and watcher install. Kick one debounced drain so a
+    // turn written immediately after install is still picked up.
+    scheduleDrain()
+    return true
+  }
+
+  // Self-rescheduling backoff poll (setTimeout, not setInterval) so a slow resolve
+  // can't overlap the next tick and the delay grows toward the cap on a long wait.
+  function scheduleResolvePoll(delayMs: number): void {
+    if (closed || watcher) {
+      return
+    }
+    resolvePollTimer = setTimeout(() => {
+      resolvePollTimer = null
+      if (closed || watcher) {
+        return
+      }
+      void resolveSessionFilePath(agent, sessionId, args)
+        .then((resolved) => {
+          // Re-check after the async resolve: unsubscribe may have run, or a
+          // prior tick may have already installed the watcher (race-safe).
+          if (closed || watcher) {
+            return
+          }
+          if (resolved && installWatcher(resolved)) {
+            return
+          }
+          scheduleResolvePoll(Math.min(delayMs * 2, RESOLVE_POLL_MAX_MS))
+        })
+        .catch(() => {
+          // A transient resolve failure must not kill the poll; keep backing off.
+          scheduleResolvePoll(Math.min(delayMs * 2, RESOLVE_POLL_MAX_MS))
+        })
+    }, delayMs)
+  }
+
+  if (currentFilePath !== null) {
+    if (!installWatcher(currentFilePath)) {
+      // File vanished between resolve and watch — preserve the original no-op.
+      return { unsubscribe: () => {} }
+    }
+  } else if (sessionId.trim()) {
+    // #8401: the session .jsonl isn't flushed yet. Re-resolve on a backing-off
+    // interval and install the watcher once it appears (then re-read from the
+    // top). A blank sessionId has nothing to resolve, so it never polls.
+    scheduleResolvePoll(resolvePollMs ?? RESOLVE_POLL_INITIAL_MS)
+  }
 
   return {
     unsubscribe: () => {
@@ -216,12 +295,16 @@ export async function subscribeNativeChatTranscript(
         return
       }
       closed = true
+      stopResolvePoll()
       if (debounceTimer) {
         clearTimeout(debounceTimer)
         debounceTimer = null
       }
-      watcher.close()
-      activeWatcherCount--
+      if (watcher) {
+        watcher.close()
+        watcher = null
+        activeWatcherCount--
+      }
     }
   }
 }

src/preload/api-types.ts

@@ -813,7 +813,11 @@ export type AiVaultApi = {
   onWindowFocused: (callback: () => void) => () => void
 }
 
-export type NativeChatReadSessionResult = { messages: NativeChatMessage[] } | { error: string }
+export type NativeChatReadSessionResult =
+  | { messages: NativeChatMessage[] }
+  // `notFound` marks a RETRYABLE miss (the session .jsonl isn't flushed yet,
+  // #8401); the renderer stays in 'loading' and retries instead of hard-failing.
+  | { error: string; notFound?: true }
 
 /** Messages appended to a live-tailed transcript since the previous emit. */
 export type NativeChatAppendedMessages = NativeChatMessage[]

src/renderer/src/components/native-chat/use-native-chat-live-session.test.ts

@@ -238,6 +238,41 @@ describe('useNativeChatLiveSession — transport routing', () => {
     expect(latest?.error).toBe('runtime too old')
   })
 
+  it('retries a notFound read on backoff instead of surfacing an error (#8401)', async () => {
+    vi.useFakeTimers()
+    try {
+      const transport = getMockTransport('env-1')
+      // First read races the lazy first flush → retryable notFound; the flush
+      // lands before the backoff retry, which then reads the real transcript.
+      transport.readSession
+        .mockResolvedValueOnce({ error: 'No transcript found', notFound: true })
+        .mockResolvedValueOnce({ messages: [assistant('a-1', 'flushed')] })
+
+      await render({
+        paneKey: PANE,
+        agent: AGENT,
+        sessionId: SESSION,
+        runtimeEnvironmentId: 'env-1'
+      })
+
+      // notFound must NOT become an error: the pane stays loading and retries.
+      expect(latest?.status).toBe('loading')
+      expect(latest?.status).not.toBe('error')
+      expect(transport.readSession).toHaveBeenCalledTimes(1)
+
+      // Advance past the first backoff step so the retry fires and resolves.
+      await act(async () => {
+        await vi.advanceTimersByTimeAsync(1000)
+      })
+
+      expect(transport.readSession).toHaveBeenCalledTimes(2)
+      expect(latest?.status).toBe('ready')
+      expect(latest?.messages.map((m) => m.id)).toContain('a-1')
+    } finally {
+      vi.useRealTimers()
+    }
+  })
+
   it('never calls the transport when there is no session id', async () => {
     await render({ paneKey: PANE, agent: AGENT, sessionId: null, runtimeEnvironmentId: 'env-1' })
 

src/renderer/src/components/native-chat/use-native-chat-live-session.ts

@@ -53,6 +53,14 @@ export type NativeChatLiveSession = NativeChatSession & {
 // Stable empty-base reference so a non-ready read doesn't churn the base axis.
 const EMPTY_MESSAGES: readonly NativeChatMessage[] = []
 
+// A just-created session's transcript is written lazily by the agent, so the
+// first read can race the first flush and return notFound (#8401). Retry with a
+// bounded exponential backoff (kept in 'loading', never 'error') until the file
+// appears, so the pane recovers on its own instead of sticking on "No transcript
+// found". The cap keeps a genuinely-never-appearing session to a light poll.
+const NOT_FOUND_RETRY_INITIAL_MS = 1000
+const NOT_FOUND_RETRY_MAX_MS = 10_000
+
 /** True when `whole`'s first `len` entries are referentially identical to
  *  `prefix` — i.e. `whole` is `prefix` extended at the tail, so the incremental
  *  assembler can splice just the suffix instead of resetting. */
@@ -167,25 +175,39 @@ export function useNativeChatLiveSession(
     setAppended([])
     setHasMore(false)
 
-    void transport
-      .readSession(agent, sessionId, limitRef.current, transcriptPath ?? undefined)
-      .then((result) => {
-        if (cancelled) {
-          return
-        }
-        if (result && 'error' in result) {
-          setRead({ phase: 'error', error: result.error })
-          return
-        }
-        const messages = result?.messages ?? []
-        setRead({ phase: 'ready', messages })
-        setHasMore(hasMoreNativeChatHistory(messages.length, limitRef.current))
-      })
-      .catch((err: unknown) => {
-        if (!cancelled) {
-          setRead({ phase: 'error', error: err instanceof Error ? err.message : String(err) })
-        }
-      })
+    // Backoff state for the notFound retry; both are cleared on teardown below.
+    let retryTimer: ReturnType<typeof setTimeout> | null = null
+    let retryDelayMs = NOT_FOUND_RETRY_INITIAL_MS
+
+    const attemptRead = (): void => {
+      void transport
+        .readSession(agent, sessionId, limitRef.current, transcriptPath ?? undefined)
+        .then((result) => {
+          if (cancelled) {
+            return
+          }
+          if (result && 'error' in result) {
+            if (result.notFound) {
+              // The transcript isn't flushed yet — stay in 'loading' and retry
+              // rather than hard-failing. The live watcher also polls for it.
+              retryTimer = setTimeout(attemptRead, retryDelayMs)
+              retryDelayMs = Math.min(retryDelayMs * 2, NOT_FOUND_RETRY_MAX_MS)
+              return
+            }
+            setRead({ phase: 'error', error: result.error })
+            return
+          }
+          const messages = result?.messages ?? []
+          setRead({ phase: 'ready', messages })
+          setHasMore(hasMoreNativeChatHistory(messages.length, limitRef.current))
+        })
+        .catch((err: unknown) => {
+          if (!cancelled) {
+            setRead({ phase: 'error', error: err instanceof Error ? err.message : String(err) })
+          }
+        })
+    }
+    attemptRead()
 
     const subscriptionId = nextSubscriptionId()
     const unsubscribe = transport.subscribe(
@@ -208,6 +230,12 @@ export function useNativeChatLiveSession(
 
     return () => {
       cancelled = true
+      if (retryTimer) {
+        // Stop a pending notFound retry so a session swap/unmount can't fire a
+        // stale read against the old session id.
+        clearTimeout(retryTimer)
+        retryTimer = null
+      }
       // Desktop returns a sync unsubscribe fn; the web RPC bridge returns a
       // Promise instead (and can't deliver streaming callbacks). Calling a
       // Promise as a function crashed the whole chat view, so resolve it first