Cache bounded conversation outlines after reader projection

2026-11-15 10:27:33 +00:00 · 2026-11-08 18:13:56 -08:00
parent d6b671ed89
commit da4b5919e3
15 changed files with 241 additions and 325 deletions
@@ -1,33 +1,11 @@
 export const JOURNAL_DOMAIN_SCHEMA_001_OUTLINE = `
-CREATE TABLE journal_outline_members (
+CREATE TABLE journal_outline_cache (
  session_id TEXT NOT NULL,
  epoch TEXT NOT NULL,
-  item_id TEXT NOT NULL,
+  source_sequence INTEGER NOT NULL,
  source_revision INTEGER NOT NULL,
-  sequence INTEGER NOT NULL,
-  sequence_index INTEGER NOT NULL,
-  ordinal INTEGER NOT NULL,
-  structure_json TEXT NOT NULL,
-  turn_key TEXT,
-  reply TEXT,
-  entry_json TEXT,
-  short_json TEXT,
-  empty_json TEXT,
-  entry_bytes INTEGER NOT NULL,
-  short_bytes INTEGER NOT NULL,
-  empty_bytes INTEGER NOT NULL,
-  PRIMARY KEY(session_id,epoch,item_id)
-) WITHOUT ROWID;
-CREATE INDEX journal_outline_entries ON journal_outline_members(session_id,epoch,sequence,sequence_index,ordinal)
-  WHERE entry_json IS NOT NULL;
-CREATE INDEX journal_outline_reply_candidates ON journal_outline_members(session_id,epoch,turn_key,sequence DESC,sequence_index DESC,ordinal DESC)
-  WHERE reply IS NOT NULL;
-CREATE TABLE journal_outline_replies (
-  session_id TEXT NOT NULL,
-  epoch TEXT NOT NULL,
-  turn_key TEXT NOT NULL,
-  reply TEXT NOT NULL,
-  reply_bytes INTEGER NOT NULL,
-  PRIMARY KEY(session_id,epoch,turn_key)
+  budget_bytes INTEGER NOT NULL,
+  outline_json TEXT NOT NULL,
+  PRIMARY KEY(session_id,epoch)
 ) WITHOUT ROWID;
 `
@@ -37,7 +37,16 @@ export class JournalSqlDatabase {
    this.readers = new JournalSqlReaderPool(
      journalDomainDatabasePath(stateDirectory),
      journalDatabasePath(stateDirectory),
-      options.readerPath
+      options.readerPath,
+      (cache) => {
+        if (!this.readOnly && !this.closed && !this.activity.isSessionActive(cache.sessionId)) {
+          void this.writer.maintain({ kind: 'outline-cache', cache }).catch((error: unknown) => {
+            if (!this.closed) {
+              options.onMaintenanceError(error, cache.sessionId)
+            }
+          })
+        }
+      }
    )
    this.conversions = new JournalSqlConversions(writer, this.readers, this.activity.waitForIdle)
    this.maintenance = new JournalSqlBackgroundMaintenance(
@@ -1,3 +1,4 @@
+import { saveJournalDomainOutlineCache } from './journal-domain-outline'
 import { afterEach, expect, it } from 'vitest'
 import {
  domainLifecycleFixture,
@@ -439,3 +440,87 @@ it('observes a consumed automation card through its first root turn and only tha
    error: null
  })
 })
+
+it('reuses a saved outline after reopen and refuses a cache result from an older source', async () => {
+  const f = domainLifecycleFixture(cleanup)
+  await f.run({
+    kind: 'item',
+    identity: identity('prompt'),
+    body: body('Original prompt'),
+    options
+  })
+  const read = () => {
+    const result = readJournalSqlPoint(f.db, {
+      sessionId: 'chat',
+      operation: { kind: 'conversation-outline', budgetBytes: 100_000 }
+    })
+    if (result.kind !== 'conversation-outline') {
+      throw new Error('outline unavailable')
+    }
+    return result
+  }
+  const cold = read()
+  if (!cold.cache) {
+    throw new Error('cold outline unavailable')
+  }
+  expect(saveJournalDomainOutlineCache(f.db, cold.cache)).toBe(true)
+  const source = f.db
+    .prepare("SELECT outline_source_json FROM journal_items WHERE item_id='orca:prompt'")
+    .get()!.outline_source_json
+  f.db
+    .prepare(
+      "UPDATE journal_items SET outline_source_json='unreadable source' WHERE item_id='orca:prompt'"
+    )
+    .run()
+  f.reopen()
+  expect(read().outline.entries).toEqual([
+    { itemId: 'orca:prompt', sequence: 1, preview: 'Original prompt', imageCount: 0 }
+  ])
+  f.db
+    .prepare("UPDATE journal_items SET outline_source_json=? WHERE item_id='orca:prompt'")
+    .run(source)
+  await f.run({ kind: 'item', identity: identity('later'), body: body('Changed prompt'), options })
+  expect(saveJournalDomainOutlineCache(f.db, cold.cache)).toBe(false)
+  const changed = read()
+  expect(changed.outline.entries).toEqual([
+    { itemId: 'orca:prompt', sequence: 1, preview: 'Original prompt', imageCount: 0 },
+    { itemId: 'orca:later', sequence: 2, preview: 'Changed prompt', imageCount: 0 }
+  ])
+  await f.run({
+    kind: 'item',
+    identity: identity('turn'),
+    options,
+    body: {
+      kind: 'turn',
+      turnId: 'turn',
+      state: 'running',
+      startedAt: 10,
+      userItemId: 'orca:prompt'
+    }
+  })
+  const running = read()
+  if (!running.cache) {
+    throw new Error('running outline unavailable')
+  }
+  expect(saveJournalDomainOutlineCache(f.db, running.cache)).toBe(false)
+  await f.run({
+    kind: 'item',
+    identity: identity('turn'),
+    options,
+    body: {
+      kind: 'turn',
+      turnId: 'turn',
+      state: 'completed',
+      startedAt: 10,
+      completedAt: 20,
+      userItemId: 'orca:prompt'
+    }
+  })
+  const idle = read()
+  if (!idle.cache) {
+    throw new Error('idle outline unavailable')
+  }
+  expect(saveJournalDomainOutlineCache(f.db, idle.cache)).toBe(true)
+  f.reopen()
+  expect(read().outline).toEqual(idle.outline)
+})
@@ -16,8 +16,7 @@ export function discardJournalDomainImportPage(
  }
  let remaining = 512
  for (const [table, key] of [
-    ['journal_outline_members', 'epoch,item_id'],
-    ['journal_outline_replies', 'epoch,turn_key'],
+    ['journal_outline_cache', 'epoch'],
    ['journal_item_subagent_names', 'epoch,subagent_id,item_id'],
    ['journal_items', 'epoch,item_id'],
    ['journal_item_tombstones', 'epoch,item_id'],
@@ -8,7 +8,6 @@ import type Database from '../../sqlite/sync-database'
 import { insertJournalDomainQueueRow, journalDomainQueueRow } from './journal-domain-queue-rows'
 import type { JournalDomainImportHeader, JournalDomainImportPage } from './journal-domain-import'
 import { writeJournalDomainItemNames } from './journal-domain-item-names'
-import { rebuildJournalDomainOutline } from './journal-domain-outline-write'

 export type JournalDomainImportState =
  | { state: 'converting'; epoch: null }
@@ -253,6 +252,5 @@ export function finishJournalDomainImport(
  if (state.state !== 'ready') {
    throw new Error('journal domain import did not publish its chat head')
  }
-  rebuildJournalDomainOutline(db, header)
  return state.epoch
 }
@@ -25,12 +25,7 @@ const RETIRED_TABLES: readonly { name: string; key: string; payload?: readonly s
      'outline_source_json'
    ]
  },
-  {
-    name: 'journal_outline_members',
-    key: 'item_id',
-    payload: ['structure_json', 'entry_json', 'short_json', 'empty_json', 'reply']
-  },
-  { name: 'journal_outline_replies', key: 'turn_key', payload: ['reply'] },
+  { name: 'journal_outline_cache', key: '', payload: ['outline_json'] },
  { name: 'journal_item_subagent_names', key: 'subagent_id,item_id' },
  { name: 'journal_item_tombstones', key: 'item_id' },
  { name: 'journal_removed_turns', key: 'turn_id' },
@@ -63,7 +58,7 @@ export function pruneJournalDomainRetiredPage(
  let deleted = 0
  let bytes = 0
  for (const { name, key, payload } of RETIRED_TABLES) {
-    const columns = ['session_id', 'epoch', ...key.split(',')]
+    const columns = ['session_id', 'epoch', ...(key ? key.split(',') : [])]
    const sizes = [...columns, ...(payload ?? [])]
      .map((column) => `COALESCE(octet_length(${column}),0)`)
      .join('+')
@@ -14,8 +14,6 @@ import { readAgentJournalTurn } from '../../../shared/agent-session/lifecycle/ag
 import { isAgentSessionContextClear } from '../../../shared/agent-session/agent-session-context-clear'
 import { projectStructuredItemToNativeChat } from '../../../shared/agent-session/view/structured-agent-session-projection'
 import { nativeChatToolFoldKind } from '../../../shared/native-chat/tools/native-chat-tool-fold'
-import { isNoiseMessage } from '../../../shared/native-chat/native-chat-noise'
-import { nativeChatRowRendersContent } from '../../../shared/native-chat/transcript/native-chat-row-content'
 import type {
  NativeChatBlock,
  NativeChatMessage
@@ -100,26 +98,6 @@ export function journalDomainOutlineSource(item: AgentJournalRenderItem): string
  } satisfies JournalOutlineSource)
 }

-/** Source position and membership only; body revisions and prose do not regroup a turn. */
-export function journalOutlineStructure(source: JournalOutlineSource): string {
-  const { revision: _revision, ...item } = source.item
-  const { blocks: _blocks, ...message } = source.message ?? { blocks: [] }
-  return JSON.stringify({
-    item,
-    message,
-    fold: source.message && nativeChatToolFoldKind(source.message),
-    noise: source.message && isNoiseMessage(source.message),
-    renders: source.message && nativeChatRowRendersContent(source.message.blocks),
-    tools: source.message?.blocks.flatMap((block) =>
-      block.type === 'tool-call' || block.type === 'tool-result' ? [[block.type, block.callId]] : []
-    )
-  })
-}
-
-export function journalOutlineMessage(source: JournalOutlineSource): NativeChatMessage | null {
-  return source.message
-}
-
 export function journalDomainOutlineSubmission(submission: AgentJournalSubmission): string {
  const {
    clientMessageId,
@@ -1,205 +0,0 @@
-import type Database from '../../sqlite/sync-database'
-import type { SqliteRow } from '../../sqlite/sqlite-statement'
-import {
-  projectAgentSessionConversationOutline,
-  truncateOutlinePreview,
-  type AgentSessionConversationOutlineEntry
-} from '../../../shared/agent-session/agent-session-conversation-outline'
-import type { AgentJournalSubmission } from '../../../shared/agent-session/journal/agent-session-journal-types'
-import {
-  journalOutlineMessage,
-  journalOutlineStructure,
-  type JournalOutlineSource
-} from './journal-domain-outline-source'
-
-type Target = { sessionId: string; epoch: string }
-type SourceRow = { source: JournalOutlineSource; ordinal: number; structure: string }
-
-function writeMember(
-  db: Database.Database,
-  target: Target,
-  row: SourceRow,
-  turnKey: string | undefined,
-  entry: AgentSessionConversationOutlineEntry | undefined
-): void {
-  const json = entry ? JSON.stringify(entry) : null
-  const short = entry
-    ? JSON.stringify({ ...entry, preview: truncateOutlinePreview(entry.preview, 60) })
-    : null
-  const empty = entry ? JSON.stringify({ ...entry, preview: '' }) : null
-  db.prepare(`INSERT INTO journal_outline_members(session_id,epoch,item_id,source_revision,
-    sequence,sequence_index,ordinal,structure_json,turn_key,reply,entry_json,short_json,empty_json,
-    entry_bytes,short_bytes,empty_bytes) VALUES(?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?)
-    ON CONFLICT(session_id,epoch,item_id) DO UPDATE SET
-      source_revision=excluded.source_revision,sequence=excluded.sequence,sequence_index=excluded.sequence_index,
-      ordinal=excluded.ordinal,structure_json=excluded.structure_json,turn_key=excluded.turn_key,
-      reply=excluded.reply,entry_json=excluded.entry_json,short_json=excluded.short_json,empty_json=excluded.empty_json,
-      entry_bytes=excluded.entry_bytes,short_bytes=excluded.short_bytes,empty_bytes=excluded.empty_bytes
-    WHERE source_revision<>excluded.source_revision OR structure_json<>excluded.structure_json
-      OR turn_key IS NOT excluded.turn_key OR reply IS NOT excluded.reply OR entry_json IS NOT excluded.entry_json`).run(
-    target.sessionId,
-    target.epoch,
-    row.source.item.itemId,
-    row.source.item.revision,
-    row.source.item.sequence,
-    row.source.item.sequenceIndex ?? 0,
-    row.ordinal,
-    row.structure,
-    turnKey ?? null,
-    row.source.reply,
-    json,
-    short,
-    empty,
-    json === null ? 0 : Buffer.byteLength(json, 'utf8') + 1,
-    short === null ? 0 : Buffer.byteLength(short, 'utf8') + 1,
-    empty === null ? 0 : Buffer.byteLength(empty, 'utf8') + 1
-  )
-}
-
-function refreshReply(db: Database.Database, target: Target, key: string): void {
-  const prefix = [target.sessionId, target.epoch, key] as const
-  const row = db
-    .prepare(`SELECT reply FROM journal_outline_members
-    INDEXED BY journal_outline_reply_candidates WHERE session_id=? AND epoch=? AND turn_key=? AND reply IS NOT NULL
-    ORDER BY sequence DESC,sequence_index DESC,ordinal DESC LIMIT 1`)
-    .get(...prefix)
-  if (!row) {
-    db.prepare(
-      'DELETE FROM journal_outline_replies WHERE session_id=? AND epoch=? AND turn_key=?'
-    ).run(...prefix)
-    return
-  }
-  const reply = String(row.reply)
-  db.prepare(`INSERT INTO journal_outline_replies(session_id,epoch,turn_key,reply,reply_bytes) VALUES(?,?,?,?,?)
-    ON CONFLICT(session_id,epoch,turn_key) DO UPDATE SET reply=excluded.reply,reply_bytes=excluded.reply_bytes
-    WHERE reply<>excluded.reply`).run(
-    ...prefix,
-    reply,
-    Buffer.byteLength(JSON.stringify({ reply }), 'utf8') - 1
-  )
-}
-
-function sourceRow(row: SqliteRow): SourceRow {
-  const source: JournalOutlineSource = JSON.parse(String(row.outline_source_json))
-  return { source, ordinal: Number(row.ordinal), structure: journalOutlineStructure(source) }
-}
-
-/** Membership changes can refer backward through aliases/Stop; reproject compact facts, never originals. */
-export function rebuildJournalDomainOutline(db: Database.Database, target: Target): void {
-  const prefix = [target.sessionId, target.epoch] as const
-  const sources = db
-    .prepare(`SELECT ordinal,outline_source_json FROM journal_items
-    INDEXED BY journal_items_visible_position WHERE session_id=? AND epoch=? AND hidden=0
-    AND outline_source_json IS NOT NULL ORDER BY sequence,sequence_index,ordinal`)
-    .all(...prefix)
-    .map(sourceRow)
-  const byId = new Map(sources.map((row) => [row.source.item.itemId, row]))
-  const submissions = db
-    .prepare(`SELECT outline_json FROM journal_submission_attempts
-    INDEXED BY journal_submission_ordinal WHERE session_id=? AND epoch=? AND current=1 ORDER BY ordinal`)
-    .all(...prefix)
-    .map((row): AgentJournalSubmission => JSON.parse(String(row.outline_json)))
-  const turnKeys = new Map<string, string>()
-  const entries = projectAgentSessionConversationOutline(
-    sources.map((row) => row.source.item),
-    submissions,
-    (messages, keys) => {
-      messages.forEach((message, index) => {
-        const key = keys[index]
-        if (key !== undefined) {
-          turnKeys.set(message.id, key)
-        }
-      })
-      return new Map()
-    },
-    {
-      projectItems: (items) =>
-        items.flatMap((item) => {
-          const source = byId.get(item.itemId)?.source
-          const message = source && journalOutlineMessage(source)
-          return message ? [message] : []
-        }),
-      userPreview: (message) => byId.get(message.id)!.source.preview!
-    }
-  )
-  const entriesById = new Map(entries.map((entry) => [entry.itemId, entry]))
-  const old = db
-    .prepare('SELECT item_id,turn_key FROM journal_outline_members WHERE session_id=? AND epoch=?')
-    .all(...prefix)
-  const affected = new Set<string>()
-  const remove = db.prepare(
-    'DELETE FROM journal_outline_members WHERE session_id=? AND epoch=? AND item_id=?'
-  )
-  for (const row of old) {
-    if (row.turn_key !== null) {
-      affected.add(String(row.turn_key))
-    }
-    if (!byId.has(String(row.item_id))) {
-      remove.run(...prefix, String(row.item_id))
-    }
-  }
-  for (const source of sources) {
-    const key = turnKeys.get(source.source.item.itemId)
-    if (key !== undefined) {
-      affected.add(key)
-    }
-    writeMember(db, target, source, key, entriesById.get(source.source.item.itemId))
-  }
-  for (const key of affected) {
-    refreshReply(db, target, key)
-  }
-}
-
-/** Stable prose revisions replace one preview/candidate; only structural facts regroup membership. */
-export function refreshJournalDomainOutline(
-  db: Database.Database,
-  target: Target,
-  itemIds: readonly string[],
-  submissionsChanged: boolean
-): void {
-  if (submissionsChanged) {
-    rebuildJournalDomainOutline(db, target)
-    return
-  }
-  const prefix = [target.sessionId, target.epoch] as const
-  const current = db.prepare(`SELECT ordinal,outline_source_json FROM journal_items
-    WHERE session_id=? AND epoch=? AND item_id=? AND hidden=0 AND outline_source_json IS NOT NULL`)
-  const member = db.prepare(`SELECT structure_json,turn_key,entry_json FROM journal_outline_members
-    WHERE session_id=? AND epoch=? AND item_id=?`)
-  const updates: { row: SourceRow; old: SqliteRow }[] = []
-  for (const id of new Set(itemIds)) {
-    const saved = current.get(...prefix, id)
-    const old = member.get(...prefix, id)
-    if (!saved && !old) {
-      continue
-    }
-    const row = saved && sourceRow(saved)
-    if (!row || !old || row.structure !== old.structure_json) {
-      rebuildJournalDomainOutline(db, target)
-      return
-    }
-    updates.push({ row, old })
-  }
-  const affected = new Set<string>()
-  for (const { row, old } of updates) {
-    const key = old.turn_key === null ? undefined : String(old.turn_key)
-    const preview = row.source.preview
-    const entry =
-      old.entry_json === null || preview === null
-        ? undefined
-        : {
-            itemId: row.source.item.itemId,
-            sequence: row.source.item.sequence,
-            preview: preview.text,
-            imageCount: preview.imageCount,
-            ...(key === undefined || key === row.source.item.itemId ? {} : { turnKey: key })
-          }
-    writeMember(db, target, row, key, entry)
-    if (key !== undefined) {
-      affected.add(key)
-    }
-  }
-  for (const key of affected) {
-    refreshReply(db, target, key)
-  }
-}
@@ -1,60 +1,126 @@
-import type { AgentSessionConversationOutlineEntry } from '../../../shared/agent-session/agent-session-conversation-outline'
+import {
+  projectAgentSessionConversationOutline,
+  type AgentSessionConversationOutline
+} from '../../../shared/agent-session/agent-session-conversation-outline'
+import type { AgentJournalSubmission } from '../../../shared/agent-session/journal/agent-session-journal-types'
+import type Database from '../../sqlite/sync-database'
+import { boundJournalConversationOutline } from './journal-outline-budget'
+import type { JournalOutlineSource } from './journal-domain-outline-source'
 import { journalDomainContextHead } from './journal-sql-continuation-context'
 import type { JournalSqlScope } from './journal-sql-scope'

-/** Choose the global degradation before reading the admitted recent suffix. */
+export type JournalOutlineCache = {
+  sessionId: string
+  epoch: string
+  sequence: number
+  revision: number
+  budgetBytes: number
+  json: string
+}
+
+/** Cold reads reconstruct compact facts; ordinary writes never regroup the chat. */
 export function readJournalDomainOutline(scope: JournalSqlScope, budgetBytes: number) {
  const { db, prefix } = scope
-  const totals = db
-    .prepare(`SELECT COUNT(*) AS count,
-    COALESCE(SUM(member.entry_bytes + COALESCE(reply.reply_bytes,0)),0) AS with_reply,
-    COALESCE(SUM(member.entry_bytes),0) AS full,
-    COALESCE(SUM(member.short_bytes),0) AS short,
-    COALESCE(SUM(member.empty_bytes),0) AS empty
-    FROM journal_outline_members member INDEXED BY journal_outline_entries
-    LEFT JOIN journal_outline_replies reply ON reply.session_id=member.session_id
-      AND reply.epoch=member.epoch AND reply.turn_key=member.turn_key
-    WHERE member.session_id=? AND member.epoch=? AND member.entry_json IS NOT NULL`)
+  const head = db
+    .prepare(
+      'SELECT last_sequence,submissions_revision FROM journal_chat_state WHERE session_id=? AND epoch=?'
+    )
    .get(...prefix)!
-  const replies = Number(totals.with_reply) <= budgetBytes
-  const variant =
-    replies || Number(totals.full) <= budgetBytes
-      ? 'entry'
-      : Number(totals.short) <= budgetBytes
-        ? 'short'
-        : 'empty'
-  const json = variant === 'entry' ? 'entry_json' : `${variant}_json`
-  const bytes = variant === 'entry' ? 'entry_bytes' : `${variant}_bytes`
-  const entries: AgentSessionConversationOutlineEntry[] = []
-  let total = 0
-  for (const row of db
-    .prepare(`SELECT member.${json} AS entry_json,
-    member.${bytes} + ${replies ? 'COALESCE(reply.reply_bytes,0)' : '0'} AS bytes,
-    ${replies ? 'reply.reply' : 'NULL'} AS reply
-    FROM journal_outline_members member INDEXED BY journal_outline_entries
-    ${
-      replies
-        ? `LEFT JOIN journal_outline_replies reply ON reply.session_id=member.session_id
-      AND reply.epoch=member.epoch AND reply.turn_key=member.turn_key`
-        : ''
+  const sequence = Number(head.last_sequence)
+  const revision = Number(head.submissions_revision)
+  const stored = db
+    .prepare(`SELECT outline_json FROM journal_outline_cache
+    WHERE session_id=? AND epoch=? AND source_sequence=? AND source_revision=? AND budget_bytes=?`)
+    .get(...prefix, sequence, revision, budgetBytes)
+  if (stored) {
+    try {
+      return { outline: scope.decode<AgentSessionConversationOutline>(stored.outline_json) }
+    } catch {
+      // A damaged cache can be reconstructed from the current compact source.
    }
-    WHERE member.session_id=? AND member.epoch=? AND member.entry_json IS NOT NULL
-    ORDER BY member.sequence DESC,member.sequence_index DESC,member.ordinal DESC`)
-    .iterate(...prefix)) {
-    const next = Number(row.bytes)
-    if (total + next > budgetBytes) {
-      break
-    }
-    total += next
-    scope.examined(row)
-    const entry = scope.decode<AgentSessionConversationOutlineEntry>(row.entry_json)
-    entries.push(row.reply === null ? entry : { ...entry, reply: String(row.reply) })
  }
-  entries.reverse()
-  return {
-    sessionId: scope.sessionId,
-    cursor: journalDomainContextHead(db, scope),
+  const sources = db
+    .prepare(`SELECT outline_source_json FROM journal_items
+    INDEXED BY journal_items_visible_position WHERE session_id=? AND epoch=? AND hidden=0
+    AND outline_source_json IS NOT NULL ORDER BY sequence,sequence_index,ordinal`)
+    .all(...prefix)
+    .map((row) => scope.decode<JournalOutlineSource>(row.outline_source_json))
+  const byId = new Map(sources.map((source) => [source.item.itemId, source]))
+  const submissions = db
+    .prepare(`SELECT outline_json FROM journal_submission_attempts
+    INDEXED BY journal_submission_ordinal WHERE session_id=? AND epoch=? AND current=1 ORDER BY ordinal`)
+    .all(...prefix)
+    .map((row) => scope.decode<AgentJournalSubmission>(row.outline_json))
+  const entries = projectAgentSessionConversationOutline(
+    sources.map((source) => source.item),
+    submissions,
+    (messages, keys) => {
+      const replies = new Map<string, string>()
+      for (let index = messages.length - 1; index >= 0; index--) {
+        const key = keys[index]
+        const reply = byId.get(messages[index].id)?.reply
+        if (key !== undefined && reply && !replies.has(key)) {
+          replies.set(key, reply)
+        }
+      }
+      return replies
+    },
+    {
+      projectItems: (items) =>
+        items.flatMap((item) => {
+          const message = byId.get(item.itemId)?.message
+          return message ? [message] : []
+        }),
+      userPreview: (message) => byId.get(message.id)!.preview!
+    }
+  )
+  const outline = boundJournalConversationOutline(
+    { sessionId: scope.sessionId, cursor: journalDomainContextHead(db, scope) },
    entries,
-    omittedEntries: Number(totals.count) - entries.length
+    budgetBytes
+  )
+  return {
+    outline,
+    cache: {
+      sessionId: scope.sessionId,
+      epoch: scope.epoch,
+      sequence,
+      revision,
+      budgetBytes,
+      json: JSON.stringify(outline)
+    } satisfies JournalOutlineCache
  }
 }
+
+/** Cache admission is optional and rechecks the reader's exact source inside the sole writer. */
+export function saveJournalDomainOutlineCache(
+  db: Database.Database,
+  cache: JournalOutlineCache
+): boolean {
+  const prefix = [cache.sessionId, cache.epoch] as const
+  if (
+    db
+      .prepare(`SELECT 1 FROM journal_items INDEXED BY journal_items_unsettled
+    WHERE session_id=? AND epoch=? AND hidden=0
+    AND (lifecycle_state IN ('running','pending') OR live_work=1) LIMIT 1`)
+      .get(...prefix) ||
+    db
+      .prepare(`SELECT 1 FROM journal_submission_attempts INDEXED BY journal_submission_sending
+    WHERE session_id=? AND epoch=? AND current=1 AND dispatch_state='pending' LIMIT 1`)
+      .get(...prefix)
+  ) {
+    return false
+  }
+  return (
+    Number(
+      db
+        .prepare(`INSERT INTO journal_outline_cache
+    (session_id,epoch,source_sequence,source_revision,budget_bytes,outline_json)
+    SELECT session_id,epoch,last_sequence,submissions_revision,?,? FROM journal_chat_state
+    WHERE session_id=? AND epoch=? AND last_sequence=? AND submissions_revision=?
+    ON CONFLICT(session_id,epoch) DO UPDATE SET source_sequence=excluded.source_sequence,
+    source_revision=excluded.source_revision,budget_bytes=excluded.budget_bytes,outline_json=excluded.outline_json`)
+        .run(cache.budgetBytes, cache.json, ...prefix, cache.sequence, cache.revision).changes
+    ) > 0
+  )
+}
@@ -13,6 +13,10 @@ export class JournalSqlActivity {
    }
  }

+  isSessionActive(sessionId: string): boolean {
+    return this.sessions.has(sessionId)
+  }
+
  hold(): () => void {
    this.foreground++
    let held = true
@@ -2,7 +2,6 @@ import { appendJournalRequestEvent } from './journal-writer-request-events'
 import type Database from '../../sqlite/sync-database'
 import type { JournalDomainEventChanges } from './journal-domain-schema'
 import { invalidateJournalDomainQueue } from './journal-domain-queue-revision'
-import { refreshJournalDomainOutline } from './journal-domain-outline-write'

 export const JOURNAL_EVENT_HISTORY_MS = 24 * 60 * 60 * 1000
 const MAX_EVENT_SEQUENCES = 4096
@@ -18,12 +17,6 @@ export function appendJournalSqlEvent(
  activity?: { fence: number; observedAt: number }
 ): void {
  const prefix = [target.sessionId, target.epoch] as const
-  refreshJournalDomainOutline(
-    db,
-    target,
-    [...changes.items.map((item) => item.itemId), ...(changes.removedItemIds ?? [])],
-    changes.submissions.length > 0
-  )
  const json = JSON.stringify(changes)
  const oversized = Buffer.byteLength(json, 'utf8') > MAX_EVENT_BYTES
  if (changes.cards.length > 0 || changes.submissions.length > 0) {
@@ -1,3 +1,4 @@
+import { saveJournalDomainOutlineCache, type JournalOutlineCache } from './journal-domain-outline'
 import type Database from '../../sqlite/sync-database'
 import type { JournalDomainImportHeader, JournalDomainImportPage } from './journal-domain-import'
 import {
@@ -21,6 +22,7 @@ import {
 } from './journal-domain-import-discard'

 export type JournalSqlMaintenance =
+  | { kind: 'outline-cache'; cache: JournalOutlineCache }
  | { kind: 'projection-state'; sessionId: string }
  | { kind: 'import-discard'; sessionId: string }
  | {
@@ -48,6 +50,8 @@ export function applyJournalSqlMaintenance(
  operation: JournalSqlMaintenance
 ): JournalSqlMaintenanceResult {
  switch (operation.kind) {
+    case 'outline-cache':
+      return saveJournalDomainOutlineCache(db, operation.cache)
    case 'projection-state':
      return journalDomainImportState(db, operation.sessionId)
    case 'import-discard':
@@ -1,3 +1,4 @@
+import type { JournalOutlineCache } from './journal-domain-outline'
 import type { JournalRequestFailureRead } from './journal-request-failure'
 import type { JournalRewindCut, JournalRewindSelection } from './journal-domain-rewind-cut'
 import type { AgentSessionConversationOutline } from '../../../shared/agent-session/agent-session-conversation-outline'
@@ -86,7 +87,11 @@ export type JournalSqlPointReadResult =
  | { kind: 'rewind-cut'; cut: JournalRewindCut | null }
  | { kind: 'fork-boundary'; boundary: JournalForkBoundary }
  | { kind: 'saved-content'; content: JournalSavedContent }
-  | { kind: 'conversation-outline'; outline: AgentSessionConversationOutline }
+  | {
+      kind: 'conversation-outline'
+      outline: AgentSessionConversationOutline
+      cache?: JournalOutlineCache
+    }
  | JournalRequestFailureResult
  | { kind: 'rewind-target'; target: JournalRewindTarget }
  | { kind: 'history-source-items'; items: AgentJournalRenderItem[] }
@@ -62,7 +62,7 @@ function read(
    case 'conversation-outline':
      return {
        kind: operation.kind,
-        outline: readJournalDomainOutline(scope, operation.budgetBytes)
+        ...readJournalDomainOutline(scope, operation.budgetBytes)
      }
    case 'request-failure':
    case 'running-request':
@@ -1,3 +1,4 @@
+import type { JournalOutlineCache } from './journal-domain-outline'
 import type { Worker } from 'node:worker_threads'
 import { spawnWorkerThread } from '../../worker-threads/worker-thread-spawn'
 import {
@@ -34,7 +35,8 @@ export class JournalSqlReaderPool {
    private readonly workerPath = resolveWorkerThreadEntryPath(
      currentWorkerEntryLayout(__dirname),
      'journal-sql-reader-entry.js'
-    )
+    ),
+    private readonly cacheOutline?: (cache: JournalOutlineCache) => void
  ) {}

  async domainHistory(request: JournalDomainHistoryRequest): Promise<AgentSessionHistoryResult> {
@@ -73,6 +75,11 @@ export class JournalSqlReaderPool {
    if (response.type !== 'point') {
      throw new Error('journal reader returned no point result')
    }
+    if (response.result.kind === 'conversation-outline' && response.result.cache) {
+      const { cache, ...result } = response.result
+      this.cacheOutline?.(cache)
+      return result
+    }
    return response.result
  }