diff --git a/mobile/src/session/MobileNativeChatFullContent.tsx b/mobile/src/session/MobileNativeChatFullContent.tsx
index 22a5f366bf3..b93323859da 100644
--- a/mobile/src/session/MobileNativeChatFullContent.tsx
+++ b/mobile/src/session/MobileNativeChatFullContent.tsx
@@ -1,15 +1,15 @@
-import { useContext, useState } from 'react'
+import { useContext, useEffect, useState } from 'react'
 import { Pressable, Text, View } from 'react-native'
 import {
   truncateToolDetail,
   MAX_TOOL_DETAIL_LENGTH
 } from '../../../src/shared/native-chat-tool-summary'
-import { isTextBlock, type NativeChatMessage } from '../../../src/shared/native-chat-types'
+import type { NativeChatMessage, NativeChatToolResultBlock } from '../../../src/shared/native-chat-types'
+import type { AgentJournalBoundedPayload, AgentJournalItemBody } from '../../../src/shared/agent-session-journal-types'
 import { styles } from './mobile-native-chat-message-styles'
 import {
   MobileNativeChatItemSourceContext,
-  readMobileNativeChatItem,
-  type MobileNativeChatItemBody
+  readMobileNativeChatItem
 } from './mobile-native-chat-item-read'
 
 // "Show full output" and "Show full message": a row the phone was sent a head of, read whole from
@@ -41,47 +41,51 @@ function ShowFull({
   )
 }
 
-function outputOf(body: MobileNativeChatItemBody | null): string | null {
-  if (body?.kind === 'tool-call' && 'output' in body) {
-    return body.output?.head ?? null
+function outputOf(body: AgentJournalItemBody | null): AgentJournalBoundedPayload | null {
+  if (body?.kind === 'tool-call') {
+    return body.output ?? null
   }
-  return body?.kind === 'diff' && 'patch' in body ? body.patch.head : null
+  return body?.kind === 'diff' ? body.patch : null
 }
 
 /** A tool's output in an opened line: its head, and the whole of it on request. */
 export function MobileNativeChatToolOutput({
-  output,
-  isError,
-  fullOutputItemId
+  body
 }: {
-  output: string
-  isError?: boolean
-  fullOutputItemId?: string
+  body: NativeChatToolResultBlock
 }): React.JSX.Element {
   const source = useContext(MobileNativeChatItemSourceContext)
-  const [full, setFull] = useState<string | null>(null)
-  const [load, setLoad] = useState<Load>('idle')
-  const clipped =
-    full === null && (fullOutputItemId !== undefined || output.length > MAX_TOOL_DETAIL_LENGTH)
+  const { output, isError, fullOutputItemId } = body
+  const client = source?.client, sessionId = source?.sessionId
+  const [expanded, setExpanded] = useState(false)
+  const [detail, setDetail] = useState<{
+    body: typeof body; client: typeof client; sessionId: typeof sessionId;
+    full?: AgentJournalBoundedPayload; load: Load
+  } | null>(null)
+  useEffect(() => () => setDetail((held) => held?.body === body && held.client === client && held.sessionId === sessionId ? null : held), [body, client, sessionId])
+  const current = detail?.body === body && detail.client === client && detail.sessionId === sessionId ? detail : null
+  const full = current?.full
+  const clipped = !full && (fullOutputItemId !== undefined || (!expanded && output.length > MAX_TOOL_DETAIL_LENGTH))
   const showFull = (): void => {
     if (fullOutputItemId === undefined || source === null) {
-      setFull(output)
+      setExpanded(true)
       return
     }
-    setLoad('loading')
+    setDetail({ body, client, sessionId, load: 'loading' })
+    const finish = (full?: AgentJournalBoundedPayload): void => {
+      setDetail((held) => held?.body === body && held.client === client && held.sessionId === sessionId ? { body, client, sessionId, full, load: full ? 'idle' : 'failed' } : held)
+    }
     readMobileNativeChatItem(source, fullOutputItemId)
-      .then((body) => {
-        setFull(outputOf(body) ?? output)
-        setLoad('idle')
-      })
-      .catch(() => setLoad('failed'))
+      .then((item) => finish(item?.itemId === fullOutputItemId ? outputOf(item.body) ?? undefined : undefined))
+      .catch(() => finish())
   }
   return (
     <View>
       <View style={[styles.toolResult, isError && styles.toolResultError]}>
-        <Text style={styles.mono}>{full ?? truncateToolDetail(output)}</Text>
+        <Text style={styles.mono}>{full ? full.head : expanded ? output : truncateToolDetail(output)}</Text>
       </View>
-      {clipped ? <ShowFull label="Show full output" load={load} onPress={showFull} /> : null}
+      {full?.truncated ? <Text style={styles.showFullText}>Showing {new TextEncoder().encode(full.head).length} of {full.byteLength} bytes.</Text> : null}
+      {clipped ? <ShowFull label="Show full output" load={current?.load ?? 'idle'} onPress={showFull} /> : null}
     </View>
   )
 }
@@ -91,35 +95,19 @@ export function useMobileNativeChatFullMessage(message: NativeChatMessage): {
   shown: NativeChatMessage
   showFull: React.JSX.Element | null
 } {
-  const source = useContext(MobileNativeChatItemSourceContext)
-  const [texts, setTexts] = useState<(string | undefined)[] | null>(null)
-  const [load, setLoad] = useState<Load>('idle')
-  if (texts) {
-    // Shortening cuts strings only, so the host's blocks line up with the row's one for one.
-    const blocks = message.blocks.map((block, index) => {
-      const text = texts[index]
-      return isTextBlock(block) && text !== undefined ? { ...block, text } : block
-    })
-    return { shown: { ...message, blocks }, showFull: null }
-  }
-  if (message.shortened !== true || source === null) {
-    return { shown: message, showFull: null }
-  }
+  const detail = useContext(MobileNativeChatItemSourceContext)?.messageDetail
+  const raw = detail?.raw(message.id)
+  const [request, setRequest] = useState<{ raw: typeof raw; load: Load } | null>(null)
+  const load = request?.raw === raw ? request?.load ?? 'idle' : 'idle'
+  const state = detail?.state(message.id)
   const showFull = (): void => {
-    setLoad('loading')
-    readMobileNativeChatItem(source, message.id)
-      .then((body) => {
-        setTexts(
-          body?.kind === 'message' && 'blocks' in body
-            ? body.blocks.map((block) => (block.type === 'text' ? block.text : undefined))
-            : []
-        )
-        setLoad('idle')
-      })
-      .catch(() => setLoad('failed'))
+    setRequest({ raw, load: 'loading' })
+    const finish = (load: Load): void => setRequest((held) => held?.raw === raw ? { raw, load } : held)
+    void detail?.load(message.id).then(() => finish('idle')).catch(() => finish('failed'))
   }
   return {
     shown: message,
-    showFull: <ShowFull label="Show full message" load={load} onPress={showFull} />
+    showFull: state === 'partial' ? <Text style={styles.showFullText}>Showing part of this message.</Text>
+      : state === 'available' ? <ShowFull label="Show full message" load={load} onPress={showFull} /> : null
   }
 }
diff --git a/mobile/src/session/MobileNativeChatOverlay.tsx b/mobile/src/session/MobileNativeChatOverlay.tsx
index 0c627e58f37..5838df57dbe 100644
--- a/mobile/src/session/MobileNativeChatOverlay.tsx
+++ b/mobile/src/session/MobileNativeChatOverlay.tsx
@@ -9,6 +9,7 @@ import { useMobileNativeChatComposerTray } from './use-mobile-native-chat-compos
 import { useMobileNativeChatVisualRenderer } from './MobileNativeChatVisual'
 import { MobileNativeChatVisualContext } from './mobile-native-chat-visual-context'
 import { MobileNativeChatItemSourceContext } from './mobile-native-chat-item-read'
+import { useMobileNativeChatMessageDetail } from './use-mobile-native-chat-message-detail'
 import {
   MobileNativeChatReplyRevealsContext,
   useMobileNativeChatReplyReveals
@@ -66,9 +67,10 @@ export function MobileNativeChatOverlay({
   const session = controller.nativeChatSession
   // The chat is drawn only with a resolved agent; the fallback never reaches the screen.
   const agent = controller.nativeChatAgent ?? ''
+  const fullContent = useMobileNativeChatMessageDetail(session.messages, controller.nativeChatItemSource)
   const folded = useMemo(
-    () => foldMobileNativeChatMessages(session.messages, agent),
-    [session.messages, agent]
+    () => foldMobileNativeChatMessages(fullContent.messages, agent),
+    [fullContent.messages, agent]
   )
   const streaming = useMobileNativeChatStreamingBubble(
     folded,
@@ -102,7 +104,7 @@ export function MobileNativeChatOverlay({
     <MobileNativeChatRowOverlaysHost conversation={{ surfaceId: sendSurfaceId, sessionId }}>
       <View style={styles.overlay}>
         <MobileNativeChatVisualContext.Provider value={visuals}>
-          <MobileNativeChatItemSourceContext.Provider value={controller.nativeChatItemSource}>
+          <MobileNativeChatItemSourceContext.Provider value={controller.nativeChatItemSource ? { ...controller.nativeChatItemSource, messageDetail: fullContent.detail } : null}>
             <MobileNativeChatReplyRevealsContext.Provider value={replyReveals}>
               <MobileNativeChatView
                 messages={session.messages}
diff --git a/mobile/src/session/MobileNativeChatToolRun.tsx b/mobile/src/session/MobileNativeChatToolRun.tsx
index ebe34bdc2b6..075ffbbdba0 100644
--- a/mobile/src/session/MobileNativeChatToolRun.tsx
+++ b/mobile/src/session/MobileNativeChatToolRun.tsx
@@ -64,9 +64,7 @@ function ResultBody({
   }
   return (
     <MobileNativeChatToolOutput
-      output={result.output}
-      isError={result.isError}
-      fullOutputItemId={result.fullOutputItemId}
+      body={result}
     />
   )
 }
diff --git a/mobile/src/session/mobile-native-chat-item-read.ts b/mobile/src/session/mobile-native-chat-item-read.ts
index 0ffd7afc29b..bd3b02164de 100644
--- a/mobile/src/session/mobile-native-chat-item-read.ts
+++ b/mobile/src/session/mobile-native-chat-item-read.ts
@@ -1,31 +1,16 @@
 import { createContext } from 'react'
 import { z } from 'zod'
+import { isAdmissibleAgentJournalRenderItem } from '../../../src/shared/agent-session-journal-schemas'
+import type { AgentJournalRenderItem } from '../../../src/shared/agent-session-journal-types'
 import { bindDeferredRpcOperation, defineRpcOperation } from '../transport/rpc-operation'
 import { rpcResultVariant } from '../transport/rpc-operation-result-reader'
 import type { MobileNativeChatVisualSource } from './mobile-native-chat-visual-read'
+import type { MobileNativeChatMessageDetail } from './use-mobile-native-chat-message-detail'
 
 // One chat item whole, for "Show full output" and "Show full message": every other read sends the
 // phone a head of long text, and the host keeps the rest.
 
-const Payload = z.object({ head: z.string(), byteLength: z.number(), truncated: z.boolean() })
-
-const itemReplySchema = z.object({
-  item: z
-    .object({
-      body: z.union([
-        z.object({ kind: z.literal('tool-call'), output: Payload.optional() }),
-        z.object({ kind: z.literal('diff'), patch: Payload }),
-        z.object({
-          kind: z.literal('message'),
-          blocks: z.array(z.object({ type: z.string(), text: z.string().optional() }))
-        }),
-        z.object({ kind: z.string() })
-      ])
-    })
-    .nullable()
-})
-
-export type MobileNativeChatItemBody = NonNullable<z.output<typeof itemReplySchema>['item']>['body']
+const itemReplySchema = z.object({ item: z.custom<AgentJournalRenderItem>(isAdmissibleAgentJournalRenderItem).nullable() })
 
 const nativeChatItemRead = bindDeferredRpcOperation(
   defineRpcOperation({
@@ -40,7 +25,7 @@ const nativeChatItemRead = bindDeferredRpcOperation(
 const READ_TIMEOUT_MS = 30_000
 
 /** Where whole items are read from; null where the host predates `agentSession.item`. */
-export const MobileNativeChatItemSourceContext = createContext<MobileNativeChatVisualSource | null>(
+export const MobileNativeChatItemSourceContext = createContext<(MobileNativeChatVisualSource & { messageDetail?: MobileNativeChatMessageDetail | null }) | null>(
   null
 )
 
@@ -49,7 +34,7 @@ export const MobileNativeChatItemSourceContext = createContext<MobileNativeChatV
 export async function readMobileNativeChatItem(
   source: MobileNativeChatVisualSource,
   itemId: string
-): Promise<MobileNativeChatItemBody | null> {
+): Promise<AgentJournalRenderItem | null> {
   const response = await nativeChatItemRead.request(
     source.client,
     { sessionId: source.sessionId, itemId },
@@ -59,5 +44,5 @@ export async function readMobileNativeChatItem(
   if (reply === null) {
     throw new Error('The host could not read this item.')
   }
-  return reply.item?.body ?? null
+  return reply.item
 }
diff --git a/mobile/src/session/use-mobile-native-chat-message-detail.test.tsx b/mobile/src/session/use-mobile-native-chat-message-detail.test.tsx
new file mode 100644
index 00000000000..7f979981ca4
--- /dev/null
+++ b/mobile/src/session/use-mobile-native-chat-message-detail.test.tsx
@@ -0,0 +1,48 @@
+import { createElement } from 'react'
+import { act, create, type ReactTestRenderer } from 'react-test-renderer'
+import { afterEach, expect, it, vi } from 'vitest'
+import type { NativeChatMessage } from '../../../src/shared/native-chat-types'
+import type { AgentJournalRenderItem } from '../../../src/shared/agent-session-journal-types'
+import type { RpcClient } from '../transport/rpc-client'
+import { foldMobileNativeChatMessages } from './mobile-native-chat-render-data'
+import { useMobileNativeChatMessageDetail } from './use-mobile-native-chat-message-detail'
+
+const reads = vi.hoisted(() => vi.fn())
+vi.mock('./mobile-native-chat-item-read', () => ({ readMobileNativeChatItem: reads }))
+// oxlint-disable-next-line typescript/consistent-type-assertions -- SAFETY: RPC is mocked; only this client's object identity is used.
+const source = { client: {} as RpcClient, sessionId: 'session' }
+let latest: ReturnType<typeof useMobileNativeChatMessageDetail> | undefined
+let renderer: ReactTestRenderer | undefined
+function Probe({ messages }: { messages: NativeChatMessage[] }) {
+  latest = useMobileNativeChatMessageDetail(messages, source)
+  return null
+}
+afterEach(() => { act(() => renderer?.unmount()); reads.mockReset() })
+
+it('prepares full raw user rows with their neighboring images and fences late same-head detail', async () => {
+  const row = (id: string, text: string): NativeChatMessage => ({ id, role: 'user', source: 'transcript', timestamp: 1, blocks: [{ type: 'text', text }] })
+  const image = row('image', '[Image: source: /repo/p.png]')
+  const prompt = { ...row('prompt', '[Image #1] head…'), shortened: true }
+  const skill = { ...row('skill', '<command-name>/plugin:example</command-name><command-args>head…</command-args>'), shortened: true }
+  const messages = [image, prompt, skill]
+  const item = (id: string, text: string, shortened = false): AgentJournalRenderItem => ({ itemId: id, sequence: 1, observedAt: 1, revision: 2, body: { kind: 'message', role: 'user', blocks: [{ type: 'text', text }] }, ...(shortened ? { shortened: true as const } : {}) })
+  await act(async () => { renderer = create(createElement(Probe, { messages })) })
+  reads.mockResolvedValueOnce(item('prompt', '[Image #1] head TAIL'))
+  await act(async () => { await latest?.detail?.load('prompt') })
+  const folded = foldMobileNativeChatMessages(latest?.messages ?? [], 'claude')
+  expect(folded[0]?.blocks).toEqual([{ type: 'image-ref', path: '/repo/p.png' }, { type: 'text', text: 'head TAIL' }])
+  reads.mockResolvedValueOnce(item('skill', '<command-name>/plugin:example</command-name><command-args>full</command-args>', true))
+  await act(async () => { await latest?.detail?.load('skill') })
+  expect(foldMobileNativeChatMessages(latest?.messages ?? [], 'claude')[1]?.blocks).toEqual([{ type: 'text', text: '/example full' }])
+  expect(latest?.detail?.state('skill')).toBe('partial')
+  const pending = Promise.withResolvers<AgentJournalRenderItem>()
+  reads.mockReturnValueOnce(pending.promise)
+  const stale = latest?.detail?.load('prompt')
+  const newer = { ...prompt }
+  await act(async () => renderer?.update(createElement(Probe, { messages: [image, newer, skill] })))
+  await act(async () => { pending.resolve(item('prompt', 'STALE')); await stale })
+  expect(latest?.messages[1]).toBe(newer)
+  reads.mockResolvedValueOnce(null)
+  await expect(latest?.detail?.load('prompt')).rejects.toThrow('Message unavailable')
+  expect(latest?.detail?.state('prompt')).toBe('available')
+})
diff --git a/mobile/src/session/use-mobile-native-chat-message-detail.ts b/mobile/src/session/use-mobile-native-chat-message-detail.ts
new file mode 100644
index 00000000000..bea8722342b
--- /dev/null
+++ b/mobile/src/session/use-mobile-native-chat-message-detail.ts
@@ -0,0 +1,59 @@
+import { useEffect, useMemo, useReducer } from 'react'
+import { isTextBlock, type NativeChatMessage } from '../../../src/shared/native-chat-types'
+import { projectStructuredItemToNativeChat } from '../../../src/shared/structured-agent-session-projection'
+import { readMobileNativeChatItem } from './mobile-native-chat-item-read'
+import type { MobileNativeChatVisualSource } from './mobile-native-chat-visual-read'
+
+export type MobileNativeChatMessageDetail = {
+  raw(id: string): NativeChatMessage | undefined
+  state(id: string): 'available' | 'partial' | 'complete' | null
+  load(id: string): Promise<void>
+}
+
+/** Substitute the original raw row; image, skill and tool preparation then run once as usual. */
+export function useMobileNativeChatMessageDetail(
+  messages: NativeChatMessage[], source: MobileNativeChatVisualSource | null
+): { messages: NativeChatMessage[]; detail: MobileNativeChatMessageDetail | null } {
+  const client = source?.client, sessionId = source?.sessionId
+  const cache = useMemo(() => ({
+    live: true, raw: new Set<NativeChatMessage>(),
+    entries: new Map<NativeChatMessage, NativeChatMessage>()
+  }), [client, sessionId])
+  const [revision, refresh] = useReducer((revision: number) => revision + 1, 0)
+  useEffect(() => {
+    cache.live = true
+    return () => { cache.live = false; cache.entries.clear() }
+  }, [cache])
+  useEffect(() => {
+    cache.raw = new Set(messages)
+    for (const raw of cache.entries.keys()) {
+      if (!cache.raw.has(raw)) cache.entries.delete(raw)
+    }
+  }, [cache, messages])
+  const byId = useMemo(() => new Map(messages.map((message) => [message.id, message])), [messages])
+  const raw = (id: string): NativeChatMessage | undefined => byId.get(id)
+  return {
+    messages: useMemo(() => messages.map((message) => cache.entries.get(message) ?? message), [cache, messages, revision]),
+    detail: source === null ? null : {
+      raw,
+      state: (id) => {
+        const original = raw(id)
+        if (!original?.shortened || !original.blocks.some(isTextBlock)) return null
+        const loaded = cache.entries.get(original)
+        return loaded ? (loaded.shortened ? 'partial' : 'complete') : 'available'
+      },
+      load: async (id) => {
+        const original = raw(id)
+        if (!original?.shortened || !original.blocks.some(isTextBlock)) throw new Error('Message unavailable')
+        const item = await readMobileNativeChatItem(source, id)
+        const projected = item?.itemId === id && item.body.kind === 'message'
+          ? projectStructuredItemToNativeChat(item) : null
+        if (!projected?.blocks.some(isTextBlock)) throw new Error('Message unavailable')
+        if (cache.live && cache.raw.has(original)) {
+          cache.entries.set(original, projected)
+          refresh()
+        }
+      }
+    }
+  }
+}
diff --git a/src/main/acp/acp-tool-timeline.ts b/src/main/acp/acp-tool-timeline.ts
index 9e561949ede..d75e0c6838d 100644
--- a/src/main/acp/acp-tool-timeline.ts
+++ b/src/main/acp/acp-tool-timeline.ts
@@ -89,12 +89,19 @@ export class AcpToolTimeline {
   private readonly turns = new BoundedMap<string, string>({
     maxEntries: MAX_PROVIDER_TIMELINE_OPEN_ENTRIES
   })
-  /** A running call's whole input and output, outside the budgeted snapshot that holds only their
-   *  preview, so its closing revision keeps them even when the closing update repeats neither. */
-  private readonly whole = new BoundedMap<string, { input?: unknown; output?: string }>({
-    maxEntries: MAX_PROVIDER_TIMELINE_OPEN_ENTRIES
+  // One latest snapshot per live call; the closing event takes ownership. Bytes are a ledger,
+  // not an RSS ceiling: provider frame limits and the live-entry count bound this finite carry.
+  private readonly whole = new BoundedMap<string, {
+    input?: unknown; output?: string; inputBytes: number; outputBytes: number
+  }>({
+    maxEntries: MAX_PROVIDER_TIMELINE_OPEN_ENTRIES,
+    sizeOf: (value, key) => value.inputBytes + value.outputBytes + Buffer.byteLength(key) + 64
   })
 
+  get retainedToolBytes(): number {
+    return this.whole.retainedBytes
+  }
+
   translate(
     raw: ToolCallUpdate,
     dialect: AcpDialect,
@@ -104,7 +111,8 @@ export class AcpToolTimeline {
     const previous = this.tools.get(update.toolCallId)
     const held = this.whole.get(update.toolCallId)
     const input = update.rawInput === undefined ? held?.input : update.rawInput
-    const output = outputText(update) ?? held?.output
+    const suppliedOutput = outputText(update)
+    const output = suppliedOutput ?? held?.output
     const exitCode = rawExitCodeSchema.safeParse(update.rawOutput).data?.exitCode
     const state =
       update.status === 'completed'
@@ -115,7 +123,18 @@ export class AcpToolTimeline {
             ? 'running'
             : (previous?.body.state ?? 'running')
     if (state === 'running') {
-      this.whole.set(update.toolCallId, { input, output })
+      if (!held && this.whole.size >= MAX_PROVIDER_TIMELINE_OPEN_ENTRIES) {
+        throw new Error('ACP tool stream capacity exceeded')
+      }
+      if (!this.whole.set(update.toolCallId, {
+        input, output,
+        inputBytes: update.rawInput === undefined ? (held?.inputBytes ?? 0)
+          : Buffer.byteLength(JSON.stringify(input) ?? ''),
+        outputBytes: suppliedOutput === undefined ? (held?.outputBytes ?? 0)
+          : Buffer.byteLength(JSON.stringify(output) ?? '')
+      })) {
+        throw new Error('ACP tool snapshot could not be retained')
+      }
     } else {
       this.whole.delete(update.toolCallId)
     }
diff --git a/src/main/codex/codex-structured-journal-translation-turn-lifecycle.test.ts b/src/main/codex/codex-structured-journal-translation-turn-lifecycle.test.ts
index 0f51961b64d..784e1b148ab 100644
--- a/src/main/codex/codex-structured-journal-translation-turn-lifecycle.test.ts
+++ b/src/main/codex/codex-structured-journal-translation-turn-lifecycle.test.ts
@@ -467,7 +467,7 @@ describe('codex turn lifecycle rows', () => {
     ])
   })
 
-  it('replays a backpressured turn boundary with its original receipt time', async () => {
+  it('replays an oversized backpressured notification with its original receipt time', async () => {
     vi.useFakeTimers()
     const connection = {
       pauseReading: vi.fn(),
@@ -483,7 +483,7 @@ describe('codex turn lifecycle rows', () => {
     })
 
     expect(
-      retries.handle(SESSION_ID, 'turn/started', { turn: { id: TURN_ID } }, 1_000, -1)
+      retries.handle(SESSION_ID, 'turn/started', { turn: { id: TURN_ID }, output: 'x'.repeat(9 * 1024 * 1024) }, 1_000, -1)
     ).toEqual({ accepted: false, reason: 'backpressure' })
     await vi.advanceTimersByTimeAsync(50)
 
diff --git a/src/main/codex/codex-structured-notification-retry.ts b/src/main/codex/codex-structured-notification-retry.ts
index 15af01da375..2e64fc805a7 100644
--- a/src/main/codex/codex-structured-notification-retry.ts
+++ b/src/main/codex/codex-structured-notification-retry.ts
@@ -122,7 +122,7 @@ export function createCodexStructuredNotificationRetry(deps: {
       state = { connection, events: [], bytes: 0, timer: null, running: false, failed: false }
       states.set(sessionId, state)
     }
-    if (state.events.length >= MAX_RETRY_EVENTS || state.bytes + bytes > MAX_RETRY_BYTES) {
+    if (state.events.length >= MAX_RETRY_EVENTS || (state.events.length > 0 && state.bytes - state.events[0].bytes + bytes > MAX_RETRY_BYTES)) {
       // A bounded queue cannot retain more traffic. Fail it truthfully so the
       // provider's generation enters host recovery instead of stranding a pause.
       fail(sessionId, state, 'notification retry queue overflow')
diff --git a/src/main/jsonl-rpc/timeline-final-tail.test.ts b/src/main/jsonl-rpc/timeline-final-tail.test.ts
index f39f9e78991..ee63969e038 100644
--- a/src/main/jsonl-rpc/timeline-final-tail.test.ts
+++ b/src/main/jsonl-rpc/timeline-final-tail.test.ts
@@ -81,16 +81,18 @@ describe('Pi final tail before host eviction', () => {
     expect(append('lifecycle-refused', true)).toEqual({ accepted: false, reason: 'backpressure' })
     const before = journal.snapshot().items.length
     vi.useFakeTimers()
+    const reply = 'Final reply' + 'r'.repeat(2 * 1024 * 1024)
+    const status = 'Final status' + 's'.repeat(17 * 1024 * 1024)
     lane.apply([
-      { type: 'text.delta', item: { id: 'reply' }, channel: 'assistant', text: 'Final reply' },
+      { type: 'text.delta', item: { id: 'reply' }, channel: 'assistant', text: reply },
       {
         type: 'item.update',
         item: 'tail',
-        body: { kind: 'status', tone: 'info', text: 'Final status' }
+        body: { kind: 'status', tone: 'info', text: status }
       }
     ])
-    lane.finalize()
-    lane.apply([{ type: 'session.ended', verdict: { state: 'interrupted', completedAt: 2 } }])
+    lane.finalize({ type: 'session.ended', verdict: { state: 'interrupted', completedAt: 2 } })
+    lane.apply([{ type: 'item.close', item: 'after-seal', body: { kind: 'status', tone: 'info', text: 'must not land' } }])
     let landed = false
     const barrier = deferred.drained().then((result) => {
       landed = true
@@ -112,14 +114,15 @@ describe('Pi final tail before host eviction', () => {
       discardSink: vi.fn()
     })
     expect(acknowledgeRelease).toHaveBeenCalledOnce()
+    expect(journal.snapshot().items.some((item) => item.body.kind === 'status' && item.body.text === 'must not land')).toBe(false)
     expect(journal.snapshot().items.map((item) => item.body)).toEqual(
       expect.arrayContaining([
         expect.objectContaining({
           kind: 'message',
           role: 'assistant',
-          blocks: [{ type: 'text', text: 'Final reply' }]
+          blocks: [{ type: 'text', text: reply }]
         }),
-        expect.objectContaining({ kind: 'status', text: 'Final status' }),
+        expect.objectContaining({ kind: 'status', text: status }),
         expect.objectContaining({
           kind: 'approval',
           resolution: expect.objectContaining({ state: 'cancelled' })
@@ -129,28 +132,19 @@ describe('Pi final tail before host eviction', () => {
     )
   })
 
-  it('fails excessive final output explicitly instead of leaving a refused tail waiting for eviction', async () => {
+  it('keeps the final transfer operation-count limit', async () => {
     const failures: unknown[] = []
     const deferred = createDeferredStructuredAgentSessionEventSink({
       ...testEventSinkLogging(SESSION),
       onFailed: (error) => failures.push(error)
     })
     cleanups.push(() => deferred.close())
-    expect(
-      deferred.sink.tryAppendTransition?.({
-        finalTail: true,
-        lifecycle: true,
-        publish: false,
-        steps: [
-          {
-            kind: 'settlement',
-            settlementId: 'oversize',
-            reservedBytes: 16 * 1024 * 1024 + 1,
-            resolve: () => []
-          }
-        ]
-      })
-    ).toEqual({ accepted: false, reason: 'failed' })
+    for (let index = 0; index <= 512; index += 1) {
+      expect(deferred.sink.tryAppendTransition?.({
+        finalTail: true, lifecycle: true, publish: false,
+        steps: [{ kind: 'settlement', settlementId: `tail:${index}`, reservedBytes: 1, resolve: () => [] }]
+      })).toEqual(index < 512 ? { accepted: true } : { accepted: false, reason: 'failed' })
+    }
     expect(failures).toEqual([
       expect.objectContaining({
         message: 'structured agent-session final tail exceeded its reserved capacity'
diff --git a/src/main/jsonl-rpc/timeline-lane.ts b/src/main/jsonl-rpc/timeline-lane.ts
index 36c759e42de..ffae11df83b 100644
--- a/src/main/jsonl-rpc/timeline-lane.ts
+++ b/src/main/jsonl-rpc/timeline-lane.ts
@@ -27,7 +27,9 @@ export type JsonlRpcTimelineLaneDeps = {
 export class JsonlRpcTimelineLane {
   private readonly assembler: ProviderTimelineAssembler
   private readonly identity: ReturnType<typeof createLegacyProviderTimelineIdentityScheme>
-  private readonly held: { event: ProviderTimelineEvent; bytes: number }[] = []
+  private readonly held: { events: { event: ProviderTimelineEvent; bytes: number }[]; bytes: number }[] = []
+  private heldEvents = 0
+  private sealed = false
   private heldBytes = 0
   private draining = false
   private ended = false
@@ -55,7 +57,7 @@ export class JsonlRpcTimelineLane {
 
   beginCommand(command: StructuredAgentSessionCommandRun): void {
     this.retry()
-    if (this.ended || this.held.length > 0) {
+    if (this.ended || this.sealed || this.held.length > 0) {
       throw new Error('Provider timeline has not drained for this command')
     }
     this.assembler.beginCommand(command)
@@ -66,19 +68,47 @@ export class JsonlRpcTimelineLane {
   }
 
   apply(events: readonly ProviderTimelineEvent[]): void {
-    if (this.ended) {
+    if (this.ended || this.sealed) {
       return
     }
-    for (const event of events) {
-      const bytes = Buffer.byteLength(JSON.stringify(event))
-      if (this.held.length >= MAX_HELD_EVENTS || this.heldBytes + bytes > MAX_HELD_BYTES) {
-        this.fail('Agent timeline queue capacity exceeded')
-        return
+    const pending = events.map((event) => ({ event, bytes: Buffer.byteLength(JSON.stringify(event)) }))
+    // Try the current frame first; only a refused suffix becomes retained head work.
+    while (this.held.length === 0 && pending.length > 0 && !this.ended) {
+      if (!this.consume(pending[0].event)) {
+        break
       }
-      this.held.push({ event, bytes })
-      this.heldBytes += bytes
-      this.retry()
+      pending.shift()
     }
+    this.notify()
+    if (pending.length === 0 || this.ended) {
+      return
+    }
+    const bytes = pending.reduce((total, entry) => total + entry.bytes, 0)
+    if (
+      this.heldEvents + pending.length > MAX_HELD_EVENTS ||
+      (this.held.length > 0 && this.heldBytes - this.held[0].bytes + bytes > MAX_HELD_BYTES)
+    ) {
+      this.fail('Agent timeline queue capacity exceeded')
+      return
+    }
+    this.held.push({ events: pending, bytes })
+    this.heldEvents += pending.length
+    this.heldBytes += bytes
+    this.retry()
+  }
+
+  private consume(event: ProviderTimelineEvent): boolean {
+    const result = this.assembler.apply(event)
+    if (!result.admission.accepted) {
+      if (result.admission.reason !== 'backpressure') {
+        this.fail(result.admission.reason)
+      }
+      return false
+    }
+    if (event.type === 'input.accepted' && !result.dropped) {
+      this.deps.onInputAccepted(event.clientMessageId)
+    }
+    return true
   }
 
   retry(): void {
@@ -90,29 +120,31 @@ export class JsonlRpcTimelineLane {
     this.draining = true
     try {
       while (this.held.length > 0 && !this.ended) {
-        const entry = this.held[0]
-        const result = this.assembler.apply(entry.event)
-        if (!result.admission.accepted) {
-          if (result.admission.reason !== 'backpressure') {
-            this.fail(result.admission.reason)
-          } else {
+        const batch = this.held[0]
+        const entry = batch.events[0]
+        if (!this.consume(entry.event)) {
+          if (!this.ended) {
             this.deps.pauseReading()
             this.retryTimer = setTimeout(() => this.retry(), 250)
             this.retryTimer.unref()
           }
           return
         }
-        this.held.shift()
+        batch.events.shift()
+        batch.bytes -= entry.bytes
         this.heldBytes -= entry.bytes
-        if (entry.event.type === 'input.accepted' && !result.dropped) {
-          this.deps.onInputAccepted(entry.event.clientMessageId)
+        this.heldEvents -= 1
+        if (batch.events.length === 0) {
+          this.held.shift()
         }
       }
     } finally {
       this.draining = false
       this.notify()
     }
-    this.deps.resumeReading()
+    if (!this.sealed && !this.ended) {
+      this.deps.resumeReading()
+    }
   }
 
   whenTurnLeaves(turnId: string): Promise<void> {
@@ -161,11 +193,23 @@ export class JsonlRpcTimelineLane {
     this.assembler.flush()
   }
 
-  finalize(): void {
-    // Admission must precede the host's exit barrier even when lifecycle writes are full.
+  finalize(end?: Extract<ProviderTimelineEvent, { type: 'session.ended' }>): void {
+    if (this.sealed || this.ended) {
+      return
+    }
+    // At most 256 held events + 128 dirty streams + this internal end: below 512 tail slots.
+    this.sealed = true
     this.finalizing = true
     this.retry()
+    if (this.ended) {
+      return
+    }
+    if (this.held.length > 0 || (end && !this.consume(end))) {
+      this.fail('Agent final timeline could not be transferred')
+      return
+    }
     this.flush()
+    this.assembler.dispose()
   }
 
   dispose(): void {
@@ -173,6 +217,7 @@ export class JsonlRpcTimelineLane {
     clearTimeout(this.retryTimer)
     this.held.length = 0
     this.heldBytes = 0
+    this.heldEvents = 0
     this.assembler.dispose()
     this.notify()
   }
diff --git a/src/main/native-chat/agent-session-journal/journal-body-ceiling.test.ts b/src/main/native-chat/agent-session-journal/journal-body-ceiling.test.ts
deleted file mode 100644
index d19078aa64e..00000000000
--- a/src/main/native-chat/agent-session-journal/journal-body-ceiling.test.ts
+++ /dev/null
@@ -1,27 +0,0 @@
-import { describe, expect, it } from 'vitest'
-import { journalBodyWithinCeiling } from './journal-body-ceiling'
-import { JOURNAL_PAYLOAD_MAX_BYTES } from './journal-payload-bounds'
-
-describe('journal body ceiling', () => {
-  it('keeps the head and tail of a text past the ceiling, and leaves the rest alone', () => {
-    const text = `start${'x'.repeat(JOURNAL_PAYLOAD_MAX_BYTES)}end`
-    const body = {
-      kind: 'tool-call',
-      input: { command: 'cat huge.log' },
-      output: { head: text, byteLength: text.length, digest: 'd', truncated: false }
-    }
-
-    const kept = journalBodyWithinCeiling(body)
-
-    expect(kept.input).toBe(body.input)
-    expect(kept.output.truncated).toBe(true)
-    expect(kept.output.byteLength).toBe(text.length)
-    expect(kept.output.head.startsWith('start')).toBe(true)
-    expect(kept.output.head.endsWith('end')).toBe(true)
-    expect(Buffer.byteLength(kept.output.head, 'utf8')).toBeLessThan(
-      JOURNAL_PAYLOAD_MAX_BYTES + 1024
-    )
-    const small = { kind: 'message', blocks: [{ type: 'text', text: 'a'.repeat(1024) }] }
-    expect(journalBodyWithinCeiling(small)).toBe(small)
-  })
-})
diff --git a/src/main/native-chat/agent-session-journal/journal-body-ceiling.ts b/src/main/native-chat/agent-session-journal/journal-body-ceiling.ts
deleted file mode 100644
index 43a3619e9b8..00000000000
--- a/src/main/native-chat/agent-session-journal/journal-body-ceiling.ts
+++ /dev/null
@@ -1,63 +0,0 @@
-// The one bound every saved item body keeps: no text in it past `JOURNAL_PAYLOAD_MAX_BYTES`.
-//
-// A single write past the journal write queue's caps stalls the chat, so a larger text keeps its
-// head and tail. It is applied where every provider's rows enter that queue
-// (structured-agent-session-event-sink.ts), so no translator has to remember it.
-
-import type { AgentJournalBoundedPayload } from '../../../shared/agent-session-journal-types'
-import { JOURNAL_PAYLOAD_MAX_BYTES, journalTextWithinCeiling } from './journal-payload-bounds'
-
-function isBoundedPayload(value: object): value is AgentJournalBoundedPayload {
-  return (
-    'head' in value &&
-    typeof value.head === 'string' &&
-    'byteLength' in value &&
-    'truncated' in value
-  )
-}
-
-function longestString(value: unknown): number {
-  if (typeof value === 'string') {
-    return value.length
-  }
-  if (typeof value !== 'object' || value === null) {
-    return 0
-  }
-  let longest = 0
-  for (const entry of Object.values(value)) {
-    longest = Math.max(longest, longestString(entry))
-  }
-  return longest
-}
-
-function ceil(value: unknown): unknown {
-  if (typeof value === 'string') {
-    return journalTextWithinCeiling(value)
-  }
-  if (typeof value !== 'object' || value === null) {
-    return value
-  }
-  if (!Array.isArray(value) && isBoundedPayload(value)) {
-    const head = journalTextWithinCeiling(value.head)
-    return head === value.head ? value : { ...value, head, truncated: true }
-  }
-  const entries = Object.entries(value)
-  const kept = entries.map(([, entry]) => ceil(entry))
-  if (kept.every((entry, index) => entry === entries[index]![1])) {
-    return value
-  }
-  return Array.isArray(value)
-    ? kept
-    : Object.fromEntries(entries.map(([key], index) => [key, kept[index]]))
-}
-
-/** `body` itself when no text in it is past the ceiling; otherwise a copy with each such text cut
- *  to its head and tail. */
-export function journalBodyWithinCeiling<T>(body: T): T {
-  // A string's UTF-16 length bounds its UTF-8 bytes from below by a third.
-  if (longestString(body) * 3 <= JOURNAL_PAYLOAD_MAX_BYTES) {
-    return body
-  }
-  // oxlint-disable-next-line typescript/consistent-type-assertions -- SAFETY: `ceil` keeps every key and shape and only shortens strings.
-  return ceil(body) as T
-}
diff --git a/src/main/native-chat/agent-session-journal/journal-completed-content.test.ts b/src/main/native-chat/agent-session-journal/journal-completed-content.test.ts
new file mode 100644
index 00000000000..7bc41093d7b
--- /dev/null
+++ b/src/main/native-chat/agent-session-journal/journal-completed-content.test.ts
@@ -0,0 +1,67 @@
+import { afterEach, expect, it, vi } from 'vitest'
+import { AGENT_JOURNAL_THREAD_SCOPE } from '../../../shared/agent-session-journal-types'
+import { AcpToolTimeline } from '../../acp/acp-tool-timeline'
+import { PiRpcMessages } from '../../pi/rpc-messages'
+import { PiRpcContextUsage } from '../../pi/rpc-context-usage'
+import { JsonlRpcTimelineLane } from '../../jsonl-rpc/timeline-lane'
+import { closeProviderTimelineRigs, openProviderTimelineRig, SESSION, GENERATION, NAMESPACE } from '../agent-session-timeline/provider-timeline-assembler-test-support'
+import { estimateStructuredAgentSessionItemBytes } from '../agent-session-wire/structured-agent-session-event-sink-estimate'
+import { journalPayload } from './journal-payload-bounds'
+
+const cleanups: (() => void)[] = []
+afterEach(async () => { cleanups.splice(0).forEach((cleanup) => cleanup()); await closeProviderTimelineRigs() })
+
+it.each(['direct', 'transition'] as const)('persists complete content through %s admission and SQLite reopen', async (path) => {
+  const rig = await openProviderTimelineRig()
+  const gate = Promise.withResolvers<void>()
+  cleanups.push(() => gate.resolve())
+  const blocked = rig.journal.readInOrder(() => gate.promise)
+  const identity = { provider: 'legacy' as const, agent: 'grok', sessionId: SESSION, recordId: 'full' }
+  const options = { turnScope: AGENT_JOURNAL_THREAD_SCOPE, lifecycle: true }
+  const text = '\u0001'.repeat(3 * 1024 * 1024) + 'MIDDLE' + 'x'.repeat(5 * 1024 * 1024) + 'TAIL'
+  const body = { kind: 'tool-call' as const, name: 'bash', input: { large: 'i'.repeat(1024 * 1024) }, state: 'completed', output: journalPayload(text) }
+  expect(rig.eventSink.tryAppendItem?.({ ...identity, recordId: 'before' }, { kind: 'status', tone: 'info', text: 'before' }, options)).toEqual({ accepted: true })
+  const append = () => path === 'direct'
+    ? rig.eventSink.tryAppendItem?.(identity, body, options)
+    : rig.sink.tryAppendTransition({ lifecycle: true, publish: true, steps: [{ kind: 'item', reservedBytes: estimateStructuredAgentSessionItemBytes(identity, body), options, resolve: () => ({ identity, body }) }] })
+  expect(append()).toEqual({ accepted: false, reason: 'backpressure' })
+  gate.resolve()
+  await blocked
+  await rig.eventSink.written?.()
+  expect(append()).toEqual({ accepted: true })
+  await rig.eventSink.written?.()
+  const reopened = await rig.reopenJournal()
+  expect(reopened.snapshot().items.map((item) => item.body)).toEqual([
+    { kind: 'status', tone: 'info', text: 'before' }, body
+  ])
+})
+
+it.each(['acp', 'pi'] as const)('transfers %s full fields at an omitted-field close without saving whole running revisions', async (agent) => {
+  const rig = await openProviderTimelineRig()
+  const onFailed = vi.fn()
+  const lane = new JsonlRpcTimelineLane({ sink: rig.sink, sessionId: SESSION, generation: GENERATION, namespace: NAMESPACE, agent: 'grok', pauseReading: vi.fn(), resumeReading: vi.fn(), onInputAccepted: vi.fn(), onFailed })
+  cleanups.push(() => lane.dispose())
+  const acp = new AcpToolTimeline(), pi = new PiRpcMessages(GENERATION, new PiRpcContextUsage())
+  const size = (agent === 'acp' ? 9 : 2) * 1024 * 1024
+  const input = { text: 'i'.repeat(size) }, output = 'o'.repeat(size)
+  for (const id of ['one', 'two']) {
+    lane.apply(agent === 'acp'
+      ? acp.translate({ toolCallId: id, name: 'bash', status: 'in_progress', rawInput: input }, {}, {})
+      : pi.tool({ type: 'tool_execution_start', toolCallId: id, toolName: 'bash', args: input }))
+    await rig.rows(); lane.retry(); await lane.drained()
+    lane.apply(agent === 'acp' ? acp.translate({ toolCallId: id, rawOutput: output }, {}, {})
+      : pi.tool({ type: 'tool_execution_update', toolCallId: id, toolName: 'bash', partialResult: { content: [{ type: 'text', text: output }] } }))
+    await rig.rows(); lane.retry(); await lane.drained()
+  }
+  expect(agent === 'acp' ? acp.retainedToolBytes : pi.retainedToolBytes).toBeGreaterThan(4 * size)
+  expect((await rig.rows()).filter((row) => row.body.kind === 'tool-call').every((row) => JSON.stringify(row.body).length < 40_000)).toBe(true)
+  for (const id of ['one', 'two']) {
+    lane.apply(agent === 'acp' ? acp.translate({ toolCallId: id, status: 'completed' }, {}, {})
+      : pi.tool({ type: 'tool_execution_end', toolCallId: id, toolName: 'bash' }))
+    await rig.rows(); lane.retry(); await lane.drained()
+  }
+  expect(agent === 'acp' ? acp.retainedToolBytes : pi.retainedToolBytes).toBe(0)
+  expect(onFailed).not.toHaveBeenCalled()
+  const reopened = await rig.reopenJournal()
+  expect(reopened.snapshot().items.map((row) => row.body)).toEqual(['one', 'two'].map((callId) => expect.objectContaining({ kind: 'tool-call', callId, input, state: 'completed', output: journalPayload(output) })))
+})
diff --git a/src/main/native-chat/agent-session-journal/journal-legacy-import.test.ts b/src/main/native-chat/agent-session-journal/journal-legacy-import.test.ts
index e2b9fb4d2ce..e6ee350cefe 100644
--- a/src/main/native-chat/agent-session-journal/journal-legacy-import.test.ts
+++ b/src/main/native-chat/agent-session-journal/journal-legacy-import.test.ts
@@ -17,6 +17,7 @@ import {
   importLegacyTranscriptIntoJournal,
   prepareLegacyTranscriptImport
 } from './journal-legacy-import'
+import { LEGACY_IMPORT_BLOCK_LIMITS } from './journal-legacy-import'
 import { openAgentSessionJournal } from './journal-store-factory'
 import type { AgentSessionJournal } from './journal-store'
 import { openTestJournalHostDatabase } from './journal-host-database-test-support'
@@ -406,8 +407,8 @@ async function importDecodedRoster(agents: RosterAgents): Promise<AgentSessionJo
   return journal
 }
 
-describe('payloads on import', () => {
-  it('keeps an imported tool result whole', async () => {
+describe('payload bounds on import', () => {
+  it('marks a clipped tool result and discards the remainder', async () => {
     const output = 'y'.repeat(64 * 1024)
     const filePath = await writeFixture('claude-big.jsonl', [
       {
@@ -429,7 +430,7 @@ describe('payloads on import', () => {
       agent: 'claude',
       sessionId: CLAUDE_SESSION,
       fence: 1,
-      options: { filePath }
+      options: { filePath, limits: { ...LEGACY_IMPORT_BLOCK_LIMITS, inlineHeadBytes: 1_024 } }
     })
 
     const item = journal.snapshot().items[0]
@@ -437,13 +438,16 @@ describe('payloads on import', () => {
     const body = item?.body
     const result = body?.kind === 'message' ? body.blocks[0] : undefined
     if (result?.type !== 'tool-result') {
-      throw new Error('expected a tool result')
+      throw new Error('expected a bounded tool result')
     }
     expect(result.callId).toBe('toolu_9')
-    expect(result.output).toBe(output)
+    expect(result.output.startsWith('y'.repeat(1_024))).toBe(true)
+    expect(result.output).toContain('65536 bytes')
+    expect(result.output).toContain('output truncated')
+    expect(result.output.length).toBeLessThan(1_200)
   })
 
-  it('bounds an imported subagent roster by entry count and id', async () => {
+  it('bounds an imported subagent roster by entry count, label and id', async () => {
     // The import reads an untrusted file: nothing upstream bounded either string.
     const oversized = 'z'.repeat(20 * 1024)
     const journal = await importDecodedRoster(
@@ -460,6 +464,7 @@ describe('payloads on import', () => {
       throw new Error('expected a subagent-group block')
     }
     expect(block.agents).toHaveLength(64)
+    expect(block.agents[0]?.label.length).toBeLessThan(oversized.length)
     expect(block.agents[0]?.id.length).toBeLessThan(oversized.length)
     expect(block.agents[0]?.id.startsWith('z')).toBe(true)
   })
@@ -552,6 +557,55 @@ describe('import failures', () => {
     expect(texts.length).toBeLessThan(lines.length)
   })
 
+  it('bounds oversized legacy tool-call input before journal publication', async () => {
+    const journalDir = join(root, 'bounded-tool-input-journal')
+    const limits = { ...LEGACY_IMPORT_BLOCK_LIMITS, inlineHeadBytes: 64 }
+    const journal = await open('claude', CLAUDE_SESSION, {
+      database: openTestJournalHostDatabase(journalDir)
+    })
+    const filePath = await writeFixture('oversized-tool-input.jsonl', [
+      {
+        parentUuid: null,
+        isSidechain: false,
+        type: 'assistant',
+        message: {
+          role: 'assistant',
+          content: [
+            {
+              type: 'tool_use',
+              id: 'toolu_large_input',
+              name: 'Edit',
+              input: { file_path: 'a.ts', patch: 'x'.repeat(10_000) }
+            }
+          ]
+        },
+        uuid: 'cc11ad00-1111-4222-8333-444455556666',
+        timestamp: '2026-08-05T10:00:09.000Z',
+        sessionId: CLAUDE_SESSION
+      }
+    ])
+
+    const result = await importLegacyTranscriptIntoJournal({
+      journal,
+      agent: 'claude',
+      sessionId: CLAUDE_SESSION,
+      fence: 1,
+      options: { filePath, limits }
+    })
+    expect(result.ok).toBe(true)
+    const imported = journal.snapshot().items[0]
+    expect(imported?.body).toMatchObject({
+      kind: 'tool-call',
+      input: {
+        truncated: true,
+        byteLength: expect.any(Number),
+        digest: expect.stringMatching(/^[0-9a-f]{64}$/),
+        head: expect.any(String)
+      }
+    })
+    expect(JSON.stringify(imported?.body)).not.toContain('x'.repeat(1_000))
+  })
+
   it('reports a missing transcript without touching the journal', async () => {
     const journal = await open('claude', CLAUDE_SESSION)
     const before = journal.epoch
@@ -610,3 +664,132 @@ describe('import failures', () => {
     expect(result).toMatchObject({ ok: false })
   })
 })
+
+// A tool call is only the SOLE block of its message when the provider wrote it
+// that way. Claude interleaves it with narration, Grok hangs `tool_calls` off a
+// row that also has text, and omp's execution cells always pair the invocation
+// with its output — so the multi-block path carries untrusted tool input too.
+describe('multi-block legacy messages', () => {
+  const limits = { ...LEGACY_IMPORT_BLOCK_LIMITS, inlineHeadBytes: 64 }
+  const oversized = 'x'.repeat(10_000)
+
+  /** The tool-call block of the first imported multi-block message. */
+  function importedToolCallBlock(journal: AgentSessionJournal): unknown {
+    for (const entry of journal.snapshot().items) {
+      if (entry.body.kind !== 'message') {
+        continue
+      }
+      const block = entry.body.blocks.find((candidate) => candidate.type === 'tool-call')
+      if (block) {
+        return block.input
+      }
+    }
+    return null
+  }
+
+  it('bounds a Claude tool call that shares its message with narration', async () => {
+    const journal = await open('claude', CLAUDE_SESSION, {
+      database: openTestJournalHostDatabase(join(root, 'claude-mixed-journal'))
+    })
+    const filePath = await writeFixture('claude-mixed.jsonl', [
+      {
+        parentUuid: null,
+        isSidechain: false,
+        type: 'assistant',
+        message: {
+          role: 'assistant',
+          content: [
+            { type: 'text', text: 'Editing the file.' },
+            {
+              type: 'tool_use',
+              id: 'toolu_mixed',
+              name: 'Edit',
+              input: { file_path: 'a.ts', patch: oversized }
+            }
+          ]
+        },
+        uuid: 'dd22be00-1111-4222-8333-444455556666',
+        timestamp: '2026-08-05T10:00:09.000Z',
+        sessionId: CLAUDE_SESSION
+      }
+    ])
+
+    const result = await importLegacyTranscriptIntoJournal({
+      journal,
+      agent: 'claude',
+      sessionId: CLAUDE_SESSION,
+      fence: 1,
+      options: { filePath, limits }
+    })
+
+    expect(result.ok).toBe(true)
+    expect(importedToolCallBlock(journal)).toMatchObject({
+      truncated: true,
+      byteLength: expect.any(Number),
+      digest: expect.stringMatching(/^[0-9a-f]{64}$/),
+      head: expect.any(String)
+    })
+    expect(JSON.stringify(journal.snapshot().items)).not.toContain('x'.repeat(1_000))
+    await journal.close()
+  })
+
+  it('bounds a Grok tool call that shares its row with assistant text', async () => {
+    const journal = await open('grok', CODEX_SESSION, {
+      database: openTestJournalHostDatabase(join(root, 'grok-mixed-journal'))
+    })
+    const filePath = await writeFixture('grok-mixed.jsonl', [
+      {
+        type: 'assistant',
+        id: 'asst-mixed',
+        timestamp: '2026-08-05T10:00:09.000Z',
+        content: [{ type: 'text', text: 'Searching.' }],
+        tool_calls: [{ id: 'c1', name: 'grep', arguments: JSON.stringify({ pattern: oversized }) }]
+      }
+    ])
+
+    const result = await importLegacyTranscriptIntoJournal({
+      journal,
+      agent: 'grok',
+      sessionId: CODEX_SESSION,
+      fence: 1,
+      options: { filePath, limits }
+    })
+
+    expect(result.ok).toBe(true)
+    expect(importedToolCallBlock(journal)).toMatchObject({ truncated: true })
+    expect(JSON.stringify(journal.snapshot().items)).not.toContain('x'.repeat(1_000))
+    await journal.close()
+  })
+
+  it('bounds an omp execution cell, whose invocation always ships with its output', async () => {
+    const journal = await open('omp', CODEX_SESSION, {
+      database: openTestJournalHostDatabase(join(root, 'omp-mixed-journal'))
+    })
+    const filePath = await writeFixture('omp-mixed.jsonl', [
+      {
+        type: 'message',
+        id: 'omp-mixed-1',
+        timestamp: '2026-08-05T10:00:09.000Z',
+        message: {
+          role: 'bashExecution',
+          command: `echo ${oversized}`,
+          output: 'done',
+          exitCode: 0
+        }
+      }
+    ])
+
+    const result = await importLegacyTranscriptIntoJournal({
+      journal,
+      agent: 'omp',
+      sessionId: CODEX_SESSION,
+      fence: 1,
+      options: { filePath, limits }
+    })
+
+    expect(result.ok).toBe(true)
+    expect(importedToolCallBlock(journal)).toMatchObject({ truncated: true })
+    expect(JSON.stringify(journal.snapshot().items)).not.toContain('x'.repeat(1_000))
+    await journal.close()
+  })
+})
diff --git a/src/main/native-chat/agent-session-journal/journal-legacy-import.ts b/src/main/native-chat/agent-session-journal/journal-legacy-import.ts
index 48955892902..01e1d246628 100644
--- a/src/main/native-chat/agent-session-journal/journal-legacy-import.ts
+++ b/src/main/native-chat/agent-session-journal/journal-legacy-import.ts
@@ -38,12 +38,21 @@ import { createLegacyIdentityTracker } from './journal-legacy-identity'
 import { createPiTranscriptCollector } from './journal-pi-active-branch'
 import { createNewestItemWindow } from './journal-newest-item-window'
 import type { JournalReplacementItem } from './journal-epoch-replacement'
+import {
+  boundInlineText,
+  boundToolInput,
+  type JournalPayloadLimits
+} from './journal-payload-bounds'
 import type { AgentSessionJournal } from './journal-store'
 
+/** Import preserves the bounded history window; the transcript remains the complete source. */
+export const LEGACY_IMPORT_BLOCK_LIMITS: JournalPayloadLimits = { inlineHeadBytes: 16 * 1024 }
+
 export type LegacyImportOptions = ResolveSessionFileOptions & {
   /** Resolve directly to this file, skipping path discovery. */
   filePath?: string
   source?: AdoptedTranscriptSource
+  limits?: JournalPayloadLimits
   decodedMessageIdentities?: true
 }
 
@@ -96,6 +105,7 @@ export async function prepareLegacyTranscriptImport(input: {
   options?: LegacyImportOptions
 }): Promise<PreparedLegacyImport> {
   const options = input.options ?? {}
+  const limits = options.limits ?? LEGACY_IMPORT_BLOCK_LIMITS
   // OMP is a Pi fork that kept Pi's session format, so OMP's decoder reads Pi's sessions too.
   const transcriptAgent =
     input.agent === 'pi' ? 'omp' : resolveNativeChatTranscriptAgent(input.agent)
@@ -103,7 +113,7 @@ export async function prepareLegacyTranscriptImport(input: {
     return { ok: false, error: `Unsupported agent for journal import: ${input.agent}` }
   }
   if (transcriptAgent === 'opencode') {
-    return prepareOpenCodeImport(input)
+    return prepareOpenCodeImport({ ...input, limits })
   }
   const filePath =
     options.filePath ?? (await resolveSessionFilePath(input.agent, input.sessionId, options))
@@ -118,7 +128,8 @@ export async function prepareLegacyTranscriptImport(input: {
       agent: input.agent,
       sessionId: input.sessionId,
       source: options.source,
-      decodedMessageIdentities: options.decodedMessageIdentities
+      decodedMessageIdentities: options.decodedMessageIdentities,
+      limits
     })
     return { ok: true, items, sourceEmpty: consumedBytes === 0 }
   } catch (err) {
@@ -132,6 +143,7 @@ async function prepareOpenCodeImport(input: {
   agent: AgentType
   sessionId: string
   options?: LegacyImportOptions
+  limits: JournalPayloadLimits
 }): Promise<PreparedLegacyImport> {
   const dbPath = input.options?.filePath
   if (input.options?.source) {
@@ -157,19 +169,20 @@ async function prepareOpenCodeImport(input: {
     sessionId: input.sessionId,
     recordId: message.id
   }))
-  const items = replacementItems(read.messages, identities)
+  const items = replacementItems(read.messages, identities, input.limits)
   return { ok: true, items, sourceEmpty: read.sourceEmpty === true }
 }
 
 function replacementItems(
   messages: readonly NativeChatMessage[],
-  identities: readonly AgentJournalItemIdentity[]
+  identities: readonly AgentJournalItemIdentity[],
+  limits: JournalPayloadLimits
 ): JournalReplacementItem[] {
   const replacement: JournalReplacementItem[] = []
   for (const [index, message] of messages.entries()) {
     const identity = identities[index]
     if (identity) {
-      replacement.push(replacementItem(message, identity))
+      replacement.push(replacementItem(message, identity, limits))
     }
   }
   return replacement
@@ -177,11 +190,12 @@ function replacementItems(
 
 function replacementItem(
   message: NativeChatMessage,
-  identity: AgentJournalItemIdentity
+  identity: AgentJournalItemIdentity,
+  limits: JournalPayloadLimits
 ): JournalReplacementItem {
   return {
     identity,
-    body: legacyItemBody(message),
+    body: legacyItemBody(message, limits),
     observedAt: message.timestamp ?? undefined,
     // Imported history is no generation's work: never current, whatever it says still runs.
     ownerFence: 0
@@ -195,8 +209,9 @@ const TRANSCRIPT_DECODERS = {
   omp: decodeOmpTranscriptLine
 } as const
 
-/** Run the real decoder while recording an identity anchor per emitted message. Only the newest
- *  messages fit the retained budget, so memory tracks what is kept, never the source's size. */
+/** Run the real decoder while recording an identity anchor per emitted message. Each message is
+ *  bounded as it is read and only the newest fit the retained budget, so memory tracks what is
+ *  kept, never the source's size. */
 async function decodeReplacementItems(input: {
   filePath: string
   transcriptAgent: keyof typeof TRANSCRIPT_DECODERS
@@ -204,6 +219,7 @@ async function decodeReplacementItems(input: {
   sessionId: string
   decodedMessageIdentities?: true
   source?: AdoptedTranscriptSource
+  limits: JournalPayloadLimits
 }): Promise<{ items: JournalReplacementItem[]; consumedBytes: number }> {
   const source = input.source
     ? adoptedTranscriptSourceObserver({
@@ -220,7 +236,7 @@ async function decodeReplacementItems(input: {
   })
   const decode = TRANSCRIPT_DECODERS[input.transcriptAgent]
   const toItem = (message: NativeChatMessage, identity: AgentJournalItemIdentity) =>
-    replacementItem(message, identity)
+    replacementItem(message, identity, input.limits)
   const retained = createNewestItemWindow(MAX_LEGACY_IMPORT_RETAINED_BYTES)
   const pi =
     input.agent === 'pi'
@@ -275,16 +291,22 @@ async function decodeReplacementItems(input: {
 
 /**
  * A message whose only content is a tool invocation becomes a tool-call item so
- * the reducer renders it as one. Everything else stays a message item. Content is
- * kept whole; only the copy sent to clients is bounded.
+ * the reducer renders it as one. Everything else stays a message item with its
+ * blocks bounded in place.
  */
-function legacyItemBody(message: NativeChatMessage): AgentJournalItemBody {
+function legacyItemBody(
+  message: NativeChatMessage,
+  limits: JournalPayloadLimits
+): AgentJournalItemBody {
   const only = message.blocks.length === 1 ? message.blocks[0] : undefined
   if (only?.type === 'tool-call') {
+    // Legacy transcripts are untrusted and can contain arbitrarily large tool
+    // arguments. Keep them on the same bounded path as live events before the
+    // replacement epoch is published.
     return {
       kind: 'tool-call',
       name: only.name,
-      input: only.input,
+      input: boundToolInput(only.input, limits),
       ...(only.callId !== undefined ? { callId: only.callId } : {}),
       state: 'completed'
     }
@@ -292,12 +314,25 @@ function legacyItemBody(message: NativeChatMessage): AgentJournalItemBody {
   return {
     kind: 'message',
     role: message.role,
-    blocks: message.blocks.map(boundRoster)
+    blocks: message.blocks.map((block) => boundBlock(block, limits))
   }
 }
 
-/** A roster's entries are keys, so an imported one keeps a bounded count and bounded ids. */
-function boundRoster(block: NativeChatBlock): NativeChatBlock {
+/** Every block that can carry untrusted bulk is bounded here, tool calls
+ *  included: a provider decoder is free to put one alongside narration, and the
+ *  sole-block path above never sees those. The remainder is discarded rather
+ *  than stored elsewhere — the marker keeps its digest and byte length, and the
+ *  source transcript remains the full copy. */
+function boundBlock(block: NativeChatBlock, limits: JournalPayloadLimits): NativeChatBlock {
+  if (block.type === 'text') {
+    return { ...block, text: boundInlineText(block.text, limits).text }
+  }
+  if (block.type === 'tool-result') {
+    return { ...block, output: boundInlineText(block.output, limits).text }
+  }
+  if (block.type === 'tool-call') {
+    return { ...block, input: boundToolInput(block.input, limits) }
+  }
   if (block.type === 'subagent-group') {
     return {
       ...block,
@@ -305,7 +340,8 @@ function boundRoster(block: NativeChatBlock): NativeChatBlock {
         ...agent,
         // The id is the roster key, so it is bounded with a digest rather than
         // clipped to a prefix that two distinct children could share.
-        id: boundSubagentEntryId(agent.id)
+        id: boundSubagentEntryId(agent.id),
+        label: boundInlineText(agent.label, limits).text
       }))
     }
   }
diff --git a/src/main/native-chat/agent-session-journal/journal-payload-bounds.ts b/src/main/native-chat/agent-session-journal/journal-payload-bounds.ts
index e579a429d58..bb18251398a 100644
--- a/src/main/native-chat/agent-session-journal/journal-payload-bounds.ts
+++ b/src/main/native-chat/agent-session-journal/journal-payload-bounds.ts
@@ -1,11 +1,4 @@
-// Journal payloads: what a row keeps of a tool output or diff.
-//
-// A row keeps the whole value; only what is sent to a client is bounded (the item wire form in
-// agent-session-wire), so no writer can turn a transport limit into lost content. Two bounds stay:
-// any text past `JOURNAL_PAYLOAD_MAX_BYTES` keeps its head and tail (journal-body-ceiling.ts), and
-// a Grok, OpenCode, OMP or Pi call still running keeps a preview that its closing revision
-// replaces. The byte clip below also serves keys and the few fields with their own named limit.
-
+// Completed content is canonical; running revisions keep previews until the full close.
 import { createHash } from 'node:crypto'
 import type { AgentJournalBoundedPayload } from '../../../shared/agent-session-journal-types'
 
@@ -14,10 +7,6 @@ export type JournalPayloadLimits = {
   inlineHeadBytes: number
 }
 
-/** Past this one write outgrows the journal write queue (16 MiB per lifecycle write), which stalls
- *  the chat, so a larger text keeps its head and tail, where a log's command and errors are. */
-export const JOURNAL_PAYLOAD_MAX_BYTES = 4 * 1024 * 1024
-
 /** What a revision of a call still running keeps where every update is a row and the open budget
  *  holds it (provider-timeline-budget.ts); its closing revision keeps the whole value. */
 export const JOURNAL_RUNNING_PREVIEW_LIMITS: JournalPayloadLimits = {
@@ -53,23 +42,6 @@ export function journalPayload(payload: string): AgentJournalBoundedPayload {
   }
 }
 
-/** `text` itself within `JOURNAL_PAYLOAD_MAX_BYTES`; past it, its head and tail. */
-export function journalTextWithinCeiling(text: string): string {
-  // UTF-8 spends at most three bytes per UTF-16 unit, so most text needs no encoding.
-  if (text.length * 3 <= JOURNAL_PAYLOAD_MAX_BYTES) {
-    return text
-  }
-  const byteLength = Buffer.byteLength(text, 'utf8')
-  if (byteLength <= JOURNAL_PAYLOAD_MAX_BYTES) {
-    return text
-  }
-  const keep = JOURNAL_PAYLOAD_MAX_BYTES / 2
-  const head = utf8Head(text, keep)
-  const tail = utf8Tail(text, keep)
-  const omitted = byteLength - Buffer.byteLength(head, 'utf8') - Buffer.byteLength(tail, 'utf8')
-  return `${head}\n… [Orca kept the start and end; ${omitted} bytes in between were not saved] …\n${tail}`
-}
-
 /** Whole once `running` is false; a preview while the call still runs. */
 export function journalToolPayload(payload: string, running: boolean): AgentJournalBoundedPayload {
   return running ? boundPayload(payload, JOURNAL_RUNNING_PREVIEW_LIMITS) : journalPayload(payload)
@@ -137,16 +109,6 @@ export function boundToolInput(input: unknown, limits: JournalPayloadLimits): un
     : input
 }
 
-/** The last `maxBytes` of `text` as UTF-8, never splitting a character. */
-function utf8Tail(text: string, maxBytes: number): string {
-  const buffer = Buffer.from(text, 'utf8')
-  let start = Math.max(0, buffer.length - maxBytes)
-  while (start < buffer.length && (buffer[start] & 0b1100_0000) === 0b1000_0000) {
-    start += 1
-  }
-  return buffer.subarray(start).toString('utf8')
-}
-
 /** Slice at a byte budget without splitting a multi-byte character. */
 function clipUtf8(buffer: Buffer, maxBytes: number): string {
   let end = maxBytes
diff --git a/src/main/native-chat/agent-session-wire/agent-session-item-wire-form.test.ts b/src/main/native-chat/agent-session-wire/agent-session-item-wire-form.test.ts
new file mode 100644
index 00000000000..1f5ceb35692
--- /dev/null
+++ b/src/main/native-chat/agent-session-wire/agent-session-item-wire-form.test.ts
@@ -0,0 +1,19 @@
+import { expect, it } from 'vitest'
+import type { AgentJournalRenderItem } from '../../../shared/agent-session-journal-types'
+import { journalPayload } from '../agent-session-journal/journal-payload-bounds'
+import { HISTORY_PAGE_CONTENT_BUDGET_BYTES } from './agent-session-history-page-bounds'
+import { agentJournalItemForWire, shortenedAgentJournalItem } from './agent-session-item-wire-form'
+
+it('preserves the full previously readable desktop message range', () => {
+  const item: AgentJournalRenderItem = { itemId: 'message', revision: 1, sequence: 1, observedAt: 1,
+    body: { kind: 'message', role: 'assistant', blocks: [{ type: 'text', text: 'x'.repeat(1_200_000) + 'TAIL' }] } }
+  expect(agentJournalItemForWire(item)).toBe(item)
+})
+
+it.each([73_728, HISTORY_PAGE_CONTENT_BUDGET_BYTES, 4 * 1024 * 1024])('keeps tool identity and output when cardinality exceeds %i bytes', (budget) => {
+  const item: AgentJournalRenderItem = { itemId: 'call', revision: 1, sequence: 1, observedAt: 1,
+    body: { kind: 'tool-call', callId: 'call', name: 'query', state: 'completed', input: { values: Array(Math.ceil(budget / 2) + 1_000).fill(0) }, output: journalPayload('done') } }
+  const sent = shortenedAgentJournalItem(item, budget)
+  expect(sent).toMatchObject({ itemId: 'call', shortened: true, body: { kind: 'tool-call', name: 'query', input: { truncated: true }, output: { head: 'done' } } })
+  expect(Buffer.byteLength(JSON.stringify(sent))).toBeLessThanOrEqual(budget)
+})
diff --git a/src/main/native-chat/agent-session-wire/agent-session-item-wire-form.ts b/src/main/native-chat/agent-session-wire/agent-session-item-wire-form.ts
index d909bcbbb73..8ba2b25d0f3 100644
--- a/src/main/native-chat/agent-session-wire/agent-session-item-wire-form.ts
+++ b/src/main/native-chat/agent-session-wire/agent-session-item-wire-form.ts
@@ -2,7 +2,7 @@
 //
 // The journal keeps tool output and diffs whole. A client is sent a head of each and the item is
 // marked `shortened`; it fetches the whole item with `agentSession.item` when the user asks. Every
-// other field is sent as kept. An item still past half a page is shortened to fit and marked
+// other field is sent as kept. An item still past a page is shortened to fit and marked
 // rather than replaced, so its row and its "show full" stay readable.
 
 import type {
@@ -10,7 +10,7 @@ import type {
   AgentJournalItemBody,
   AgentJournalRenderItem
 } from '../../../shared/agent-session-journal-types'
-import { utf8Head } from '../agent-session-journal/journal-payload-bounds'
+import { boundToolInput, JOURNAL_RUNNING_PREVIEW_LIMITS, utf8Head } from '../agent-session-journal/journal-payload-bounds'
 import {
   HISTORY_PAGE_CONTENT_BUDGET_BYTES,
   type HistoryReader
@@ -20,8 +20,8 @@ import { jsonBytes, shortenJsonStringsToFit } from './json-string-shortening'
 /** Each tool output or diff as sent: the head older clients have always been sent. */
 export const AGENT_SESSION_WIRE_PAYLOAD_HEAD_BYTES = 16 * 1024
 
-/** Half a page, so an item and the submission it carries always fit one. */
-const CLIENT_ITEM_MAX_BYTES = HISTORY_PAGE_CONTENT_BUDGET_BYTES / 2
+/** Preserve every ordinary message that already fits a desktop page. */
+const CLIENT_ITEM_MAX_BYTES = HISTORY_PAGE_CONTENT_BUDGET_BYTES
 
 /** The payload as sent; itself when its head already fits. */
 function wirePayload(payload: AgentJournalBoundedPayload): AgentJournalBoundedPayload {
@@ -60,10 +60,14 @@ export function shortenedAgentJournalItem(
   if (jsonBytes(item) <= maxBytes) {
     return item
   }
-  const body = shortenJsonStringsToFit(
-    item.body,
-    maxBytes - (jsonBytes({ ...item, body: null, shortened: true }) - jsonBytes(null))
-  )
+  const budget = maxBytes - (jsonBytes({ ...item, body: null, shortened: true }) - jsonBytes(null))
+  let body = shortenJsonStringsToFit(item.body, budget)
+  if (body === null && item.body.kind === 'tool-call') {
+    body = shortenJsonStringsToFit(
+      { ...item.body, input: boundToolInput(item.body.input, JOURNAL_RUNNING_PREVIEW_LIMITS) },
+      budget
+    )
+  }
   return body === null ? null : { ...item, body, shortened: true }
 }
 
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-event-sink-queue.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-event-sink-queue.ts
index 3d5d9847400..2adf4328944 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-event-sink-queue.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-event-sink-queue.ts
@@ -176,14 +176,16 @@ export class StructuredAgentSessionSinkQueue {
       this.lifecycleQueuedBytes - (replaced ? lifecycleCost(replaced) : 0) + lifecycleBytes
     const nextLifecycleOperations =
       this.lifecycleQueuedOperations - (replaced?.lifecycle ? 1 : 0) + (lifecycle ? 1 : 0)
+    // A byte watermark paces waiting work; an empty budget can own one complete operation.
     const exceedsOrdinary =
       !finalTail &&
       !lifecycle &&
-      (nextBytes > this.deps.watermarks.maxQueuedBytes ||
+      ((this.queuedOperations > 0 && nextBytes > this.deps.watermarks.maxQueuedBytes) ||
         nextOperations > this.deps.watermarks.maxQueuedOperations)
     const exceedsLifecycle =
       lifecycle &&
-      (nextLifecycleBytes > this.deps.watermarks.maxLifecycleQueuedBytes ||
+      ((this.lifecycleQueuedOperations > 0 &&
+        nextLifecycleBytes > this.deps.watermarks.maxLifecycleQueuedBytes) ||
         nextLifecycleOperations > this.deps.watermarks.maxLifecycleQueuedOperations)
     if (exceedsOrdinary || exceedsLifecycle) {
       this.setBackpressure(true)
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-event-sink.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-event-sink.ts
index e2ed3d46f3b..1f48f068058 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-event-sink.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-event-sink.ts
@@ -8,8 +8,9 @@ import type {
 import type { AgentSessionTurnActivity } from '../../../shared/agent-session-wire'
 import type { AgentSessionJournal } from '../agent-session-journal/journal-store'
 import type { JournalLifecycleIdentityMutationInput } from '../agent-session-journal/journal-row-builders'
+import { estimateStructuredAgentSessionItemBytes } from './structured-agent-session-event-sink-estimate'
 import { StructuredAgentSessionSinkQueue } from './structured-agent-session-event-sink-queue'
-import { createStructuredAgentSessionItemAppend } from './structured-agent-session-item-append'
+import { structuredAgentSessionJournalAppendOptions } from './structured-agent-session-journal-append-options'
 import { createStructuredAgentSessionResolvedAppend } from './structured-agent-session-resolved-append'
 import {
   createStructuredAgentSessionTransitionMembers,
@@ -231,7 +232,27 @@ export function createDeferredStructuredAgentSessionEventSink(deps: {
     ...(deps.onBackpressureChange ? { onBackpressureChange: deps.onBackpressureChange } : {})
   })
   const resolvedAppend = createStructuredAgentSessionResolvedAppend(queue)
-  const { appendItem, appendLifecycleBatch } = createStructuredAgentSessionItemAppend(queue)
+
+  const appendLifecycleBatch = (
+    settlementId: string,
+    mutations: readonly JournalLifecycleIdentityMutationInput[],
+    options: StructuredAgentSessionAppendOptions = {}
+  ): StructuredAgentSessionSinkAdmission =>
+    queue.submit(
+      {
+        bytes: Buffer.byteLength(JSON.stringify({ settlementId, mutations }), 'utf8') + 512,
+        run: (bound) =>
+          bound.journal.appendLifecycleBatch({
+            settlementId,
+            mutations,
+            // No row-level linkage: each mutation names its own (see the batch row builder).
+            fence: bound.fence,
+            // The provider's own observation: its child's generation produced every item it creates.
+            ownerFence: bound.fence
+          })
+      },
+      { ...options, lifecycle: true }
+    )
 
   const publish = (
     options: StructuredAgentSessionPublishOptions = {}
@@ -245,6 +266,24 @@ export function createDeferredStructuredAgentSessionEventSink(deps: {
       options
     )
 
+  const appendItem: NonNullable<StructuredAgentSessionEventSink['tryAppendItem']> = (
+    identity,
+    body,
+    options
+  ) =>
+    queue.submit(
+      {
+        bytes: estimateStructuredAgentSessionItemBytes(identity, body),
+        run: (bound) =>
+          bound.journal.appendItem(
+            identity,
+            body,
+            structuredAgentSessionJournalAppendOptions(bound.fence, options)
+          )
+      },
+      options
+    )
+
   return {
     sink: {
       appendItem: (identity, body, options) => {
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-final-tail-reservation.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-final-tail-reservation.ts
index 92b8e0f897f..c64b16ce91d 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-final-tail-reservation.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-final-tail-reservation.ts
@@ -1,7 +1,6 @@
-const MAX_FINAL_TAIL_BYTES = 16 * 1024 * 1024
 const MAX_FINAL_TAIL_OPERATIONS = 512
 
-/** Finalized providers can admit their bounded tail before the host takes its exit barrier. */
+/** A sealed lane transfers already-observed work before the host takes its exit barrier. */
 export class StructuredAgentSessionFinalTailReservation {
   private bytes = 0
   private operations = 0
@@ -12,7 +11,6 @@ export class StructuredAgentSessionFinalTailReservation {
       this.closed ||
       !Number.isSafeInteger(bytes) ||
       bytes < 0 ||
-      this.bytes + bytes > MAX_FINAL_TAIL_BYTES ||
       this.operations >= MAX_FINAL_TAIL_OPERATIONS
     ) {
       return null
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-item-append.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-item-append.ts
deleted file mode 100644
index d00f080bd64..00000000000
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-item-append.ts
+++ /dev/null
@@ -1,69 +0,0 @@
-// Plain item and lifecycle-batch appends. Each body is held to the journal body ceiling as it
-// enters the write queue, so no one write outgrows the queue's caps and stalls the chat.
-
-import { journalBodyWithinCeiling } from '../agent-session-journal/journal-body-ceiling'
-import type { JournalLifecycleIdentityMutationInput } from '../agent-session-journal/journal-row-builders'
-import type {
-  StructuredAgentSessionAppendOptions,
-  StructuredAgentSessionEventSink,
-  StructuredAgentSessionSinkAdmission
-} from './structured-agent-session-event-sink'
-import { estimateStructuredAgentSessionItemBytes } from './structured-agent-session-event-sink-estimate'
-import type { StructuredAgentSessionSinkQueue } from './structured-agent-session-event-sink-queue'
-import { structuredAgentSessionJournalAppendOptions } from './structured-agent-session-journal-append-options'
-
-function mutationWithinCeiling(
-  mutation: JournalLifecycleIdentityMutationInput
-): JournalLifecycleIdentityMutationInput {
-  if (mutation.kind !== 'item') {
-    return mutation
-  }
-  const body = journalBodyWithinCeiling(mutation.body)
-  return body === mutation.body ? mutation : { ...mutation, body }
-}
-
-export function createStructuredAgentSessionItemAppend(queue: StructuredAgentSessionSinkQueue): {
-  appendItem: NonNullable<StructuredAgentSessionEventSink['tryAppendItem']>
-  appendLifecycleBatch: (
-    settlementId: string,
-    mutations: readonly JournalLifecycleIdentityMutationInput[],
-    options?: StructuredAgentSessionAppendOptions
-  ) => StructuredAgentSessionSinkAdmission
-} {
-  return {
-    appendItem: (identity, written, options) => {
-      const body = journalBodyWithinCeiling(written)
-      return queue.submit(
-        {
-          bytes: estimateStructuredAgentSessionItemBytes(identity, body),
-          run: (bound) =>
-            bound.journal.appendItem(
-              identity,
-              body,
-              structuredAgentSessionJournalAppendOptions(bound.fence, options)
-            )
-        },
-        options
-      )
-    },
-    appendLifecycleBatch: (settlementId, written, options = {}) => {
-      const mutations = written.map(mutationWithinCeiling)
-      return queue.submit(
-        {
-          bytes: Buffer.byteLength(JSON.stringify({ settlementId, mutations }), 'utf8') + 512,
-          run: (bound) =>
-            bound.journal.appendLifecycleBatch({
-              settlementId,
-              mutations,
-              // No row-level linkage: each mutation names its own (see the batch row builder).
-              fence: bound.fence,
-              // The provider's own observation: its child's generation produced every item it
-              // creates.
-              ownerFence: bound.fence
-            })
-        },
-        { ...options, lifecycle: true }
-      )
-    }
-  }
-}
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-resolved-append.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-resolved-append.ts
index 6859646b6eb..d3640db2a0c 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-resolved-append.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-resolved-append.ts
@@ -3,7 +3,6 @@ import type {
   AgentJournalItemIdentity
 } from '../../../shared/agent-session-journal-types'
 import { estimateStructuredAgentSessionItemBytes } from './structured-agent-session-event-sink-estimate'
-import { journalBodyWithinCeiling } from '../agent-session-journal/journal-body-ceiling'
 import type {
   StructuredAgentSessionItemAppendOptions,
   StructuredAgentSessionEventSink,
@@ -63,9 +62,8 @@ export function createStructuredAgentSessionResolvedAppend(
     )
   const ITEM_OVERFLOW = 'structured agent-session resolved item exceeded its reserved size'
   const identityOnly = (publish: boolean) =>
-    ((identitySizeBound, written, resolveIdentity, options) => {
-      const body = journalBodyWithinCeiling(written)
-      return submit(
+    ((identitySizeBound, body, resolveIdentity, options) =>
+      submit(
         estimateStructuredAgentSessionItemBytes(identitySizeBound, body) + (publish ? 1 : 0),
         (journal) => {
           const identity = resolveIdentity(journal)
@@ -73,8 +71,7 @@ export function createStructuredAgentSessionResolvedAppend(
         },
         options,
         { publish, overflow: ITEM_OVERFLOW }
-      )
-    }) satisfies NonNullable<StructuredAgentSessionEventSink['tryAppendResolvedItem']>
+      )) satisfies NonNullable<StructuredAgentSessionEventSink['tryAppendResolvedItem']>
   return {
     tryAppendResolvedItem: identityOnly(false),
     tryAppendResolvedItemAndPublish: identityOnly(true),
diff --git a/src/main/pi/rpc-messages.ts b/src/main/pi/rpc-messages.ts
index 0d6d49b0711..c1ebfb5695b 100644
--- a/src/main/pi/rpc-messages.ts
+++ b/src/main/pi/rpc-messages.ts
@@ -1,4 +1,6 @@
 import { z } from 'zod'
+import { BoundedMap } from '../../shared/bounded-map'
+import { MAX_PROVIDER_TIMELINE_OPEN_ENTRIES } from '../native-chat/agent-session-timeline/provider-timeline-budget'
 import type { AgentJournalToolCallItem } from '../../shared/agent-session-journal-types'
 import {
   boundToolInput,
@@ -19,9 +21,17 @@ export class PiRpcMessages {
   private active?: number
   private readonly text = new Map<string, { index: number; channel: 'assistant' | 'reasoning' }>()
   private readonly tools = new Map<string, AgentJournalToolCallItem>()
-  /** A running call's whole input and output, apart from `tools`, which holds the previews the open
-   *  budget counts, so its closing revision keeps them though Pi's end event repeats no args. */
-  private readonly whole = new Map<string, { input?: unknown; output?: string }>()
+  // Closing events take these latest full fields; running journal rows retain only previews.
+  private readonly whole = new BoundedMap<string, {
+    input?: unknown; output?: string; inputBytes: number; outputBytes: number
+  }>({
+    maxEntries: MAX_PROVIDER_TIMELINE_OPEN_ENTRIES,
+    sizeOf: (value, key) => value.inputBytes + value.outputBytes + Buffer.byteLength(key) + 64
+  })
+
+  get retainedToolBytes(): number {
+    return this.whole.retainedBytes
+  }
 
   constructor(
     private readonly generation: string,
@@ -141,7 +151,18 @@ export class PiRpcMessages {
         throw new Error('Pi tool stream capacity exceeded')
       }
       this.tools.set(event.toolCallId, body)
-      this.whole.set(event.toolCallId, { input, output })
+      if (!held && this.whole.size >= MAX_PROVIDER_TIMELINE_OPEN_ENTRIES) {
+        throw new Error('Pi tool stream capacity exceeded')
+      }
+      if (!this.whole.set(event.toolCallId, {
+        input, output,
+        inputBytes: event.args === undefined ? (held?.inputBytes ?? 0)
+          : Buffer.byteLength(JSON.stringify(input) ?? ''),
+        outputBytes: result === undefined ? (held?.outputBytes ?? 0)
+          : Buffer.byteLength(JSON.stringify(output) ?? '')
+      })) {
+        throw new Error('Pi tool snapshot could not be retained')
+      }
       if (
         [...this.tools.values()].reduce(
           (bytes, tool) => bytes + Buffer.byteLength(JSON.stringify(tool)),
diff --git a/src/main/pi/rpc-session.ts b/src/main/pi/rpc-session.ts
index ae693653df4..c7cfea87065 100644
--- a/src/main/pi/rpc-session.ts
+++ b/src/main/pi/rpc-session.ts
@@ -258,11 +258,9 @@ export class PiRpcSession {
     this.publishedExit = true
     this.dialogs.cancelAll()
     this.turns.end()
-    this.lane.finalize()
-    this.lane.apply([
-      { type: 'session.ended', verdict: { state: 'interrupted', completedAt: Date.now() } }
-    ])
-    this.lane.flush()
+    this.lane.finalize({
+      type: 'session.ended', verdict: { state: 'interrupted', completedAt: Date.now() }
+    })
     let timer: ReturnType<typeof setTimeout> | undefined
     try {
       await Promise.race([
diff --git a/src/renderer/src/components/native-chat/NativeChatToolOutput.test.tsx b/src/renderer/src/components/native-chat/NativeChatToolOutput.test.tsx
new file mode 100644
index 00000000000..045a7dbcab2
--- /dev/null
+++ b/src/renderer/src/components/native-chat/NativeChatToolOutput.test.tsx
@@ -0,0 +1,42 @@
+// @vitest-environment happy-dom
+import { act } from 'react'
+import { createRoot } from 'react-dom/client'
+import { afterEach, expect, it, vi } from 'vitest'
+import type { AgentJournalRenderItem } from '../../../../shared/agent-session-journal-types'
+import type { NativeChatToolResultBlock } from '../../../../shared/native-chat-types'
+import { NativeChatToolOutput } from './NativeChatToolOutput'
+
+const mocks = vi.hoisted(() => ({ read: vi.fn(), owner: { target: { kind: 'local' }, sessionId: 'session', worktreeId: 'workspace' } }))
+vi.mock('./native-chat-visual-owner', () => ({ useNativeChatVisualOwner: () => mocks.owner }))
+vi.mock('@/runtime/structured-agent-session-client', () => ({ supportsStructuredAgentSessionItemDetail: async () => true, readStructuredAgentSessionItem: mocks.read }))
+const container = document.createElement('div')
+const root = createRoot(container)
+afterEach(() => { act(() => root.unmount()); mocks.read.mockReset() })
+
+it('fences same-head live revisions and late replies, and keeps null/partial results truthful', async () => {
+  const body: NativeChatToolResultBlock = { type: 'tool-result', output: 'x'.repeat(16_384), fullOutputItemId: 'call' }
+  const response = (text: string, truncated = false): AgentJournalRenderItem => ({ itemId: 'call', revision: 2, sequence: 1, observedAt: 1, body: { kind: 'tool-call', name: 'bash', input: null, state: 'running', output: { head: text, byteLength: 100_000, digest: 'd', truncated } } })
+  const render = (block: NativeChatToolResultBlock) => act(() => root.render(<NativeChatToolOutput body={block} />))
+  const click = async () => { await act(async () => container.querySelector('button')?.click()) }
+  render(body)
+  mocks.read.mockResolvedValueOnce(response('OLD TAIL'))
+  await click()
+  expect(container.textContent).toContain('OLD TAIL')
+  render({ ...body })
+  expect(container.textContent).not.toContain('OLD TAIL')
+  expect(container.querySelector('button')).not.toBeNull()
+  const pending = Promise.withResolvers<AgentJournalRenderItem>()
+  mocks.read.mockReturnValueOnce(pending.promise)
+  await click()
+  render({ ...body })
+  await act(async () => pending.resolve(response('STALE TAIL')))
+  expect(container.textContent).not.toContain('STALE TAIL')
+  mocks.read.mockResolvedValueOnce(null)
+  await click()
+  expect(container.textContent).toContain("Couldn't load the full output.")
+  expect(container.querySelector('button')).not.toBeNull()
+  mocks.read.mockResolvedValueOnce(response('PARTIAL', true))
+  await click()
+  expect(container.textContent).toContain('Showing')
+  expect(container.textContent).toContain('PARTIAL')
+})
diff --git a/src/renderer/src/components/native-chat/NativeChatToolOutput.tsx b/src/renderer/src/components/native-chat/NativeChatToolOutput.tsx
index b641caf0d78..05398b5d30d 100644
--- a/src/renderer/src/components/native-chat/NativeChatToolOutput.tsx
+++ b/src/renderer/src/components/native-chat/NativeChatToolOutput.tsx
@@ -1,4 +1,4 @@
-import { useState } from 'react'
+import { useEffect, useState } from 'react'
 import { Button } from '@/components/ui/button'
 import { cn } from '@/lib/utils'
 import { translate } from '@/i18n/i18n'
@@ -16,8 +16,7 @@ import { MAX_TOOL_DETAIL_LENGTH } from '../../../../shared/native-chat-tool-summ
 import { useNativeChatVisualOwner } from './native-chat-visual-owner'
 import { truncateToolDetail } from './native-chat-tool-summary'
 
-/** `partial`: Orca kept only part of this output (past its storage ceiling) or the item was more
- *  than one reply carries. */
+/** A partial detail response retains its original byte count. */
 type FullOutput = { text: string; partial: { shown: number; total: number } | null }
 
 function fullPayload(body: AgentJournalItemBody): AgentJournalBoundedPayload | null {
@@ -35,44 +34,49 @@ export function NativeChatToolOutput({
   body: NativeChatToolResultBlock
 }): React.JSX.Element {
   const owner = useNativeChatVisualOwner()
-  const [full, setFull] = useState<FullOutput | null>(null)
-  const [loading, setLoading] = useState(false)
-  const [failed, setFailed] = useState(false)
+  const [expanded, setExpanded] = useState(false)
+  const [detail, setDetail] = useState<{
+    body: NativeChatToolResultBlock; owner: typeof owner; full?: FullOutput;
+    loading?: boolean; failed?: boolean
+  } | null>(null)
+  useEffect(() => () => setDetail((held) => held?.body === body && held.owner === owner ? null : held), [body, owner])
+  const current = detail?.body === body && detail.owner === owner ? detail : null
+  const full = current?.full
+  const loading = current?.loading === true
+  const failed = current?.failed === true
   const clipped =
-    full === null &&
-    (body.fullOutputItemId !== undefined || body.output.length > MAX_TOOL_DETAIL_LENGTH)
+    !full &&
+    (body.fullOutputItemId !== undefined || (!expanded && body.output.length > MAX_TOOL_DETAIL_LENGTH))
 
   const showFull = async (): Promise<void> => {
     const itemId = body.fullOutputItemId
     if (itemId === undefined || owner === null) {
-      setFull({ text: body.output, partial: null })
+      setExpanded(true)
       return
     }
-    setLoading(true)
-    setFailed(false)
+    setDetail({ body, owner, loading: true })
+    const finish = (result: { full?: FullOutput; failed?: boolean }): void => {
+      setDetail((held) => held?.body === body && held.owner === owner ? { body, owner, ...result } : held)
+    }
     try {
-      // An older host keeps only the head it already sent.
-      const item = (await supportsStructuredAgentSessionItemDetail(owner.target))
-        ? await readStructuredAgentSessionItem(owner.target, owner.sessionId, itemId)
-        : null
-      const payload = item ? fullPayload(item.body) : null
-      setFull(
-        payload
-          ? {
-              text: payload.head,
-              partial: payload.truncated
-                ? {
-                    shown: new TextEncoder().encode(payload.head).length,
-                    total: payload.byteLength
-                  }
-                : null
-            }
-          : { text: body.output, partial: null }
-      )
+      if (!(await supportsStructuredAgentSessionItemDetail(owner.target))) {
+        setExpanded(true)
+        finish({})
+        return
+      }
+      const item = await readStructuredAgentSessionItem(owner.target, owner.sessionId, itemId)
+      const payload = item?.itemId === itemId ? fullPayload(item.body) : null
+      if (!payload) {
+        throw new Error('Output is unavailable')
+      }
+      finish({ full: {
+        text: payload.head,
+        partial: payload.truncated ? {
+          shown: new TextEncoder().encode(payload.head).length, total: payload.byteLength
+        } : null
+      } })
     } catch {
-      setFailed(true)
-    } finally {
-      setLoading(false)
+      finish({ failed: true })
     }
   }
 
@@ -85,7 +89,7 @@ export function NativeChatToolOutput({
           body.isError ? 'text-destructive' : 'text-chat-foreground'
         )}
       >
-        {full ? full.text : truncateToolDetail(body.output)}
+        {full ? full.text : expanded ? body.output : truncateToolDetail(body.output)}
       </pre>
       {full?.partial ? (
         <p className="text-xs text-chat-foreground-faint">
diff --git a/src/shared/structured-agent-session-projection.ts b/src/shared/structured-agent-session-projection.ts
index 6477afefae3..6a2ce2d08da 100644
--- a/src/shared/structured-agent-session-projection.ts
+++ b/src/shared/structured-agent-session-projection.ts
@@ -209,7 +209,7 @@ export function projectStructuredItemToNativeChat(
         ...lifecycle,
         ...(command ? { command } : {}),
         ...(from && projected.role === 'user' ? { from } : {}),
-        ...(item.shortened ? { shortened: true } : {})
+        ...(item.shortened && item.body.kind === 'message' ? { shortened: true } : {})
       }
     : null
   projectedItems.set(item, message)