perf: isolate chat streaming renders and reduce sidebar render cost (#1672)

Reworks the chat and session-sidebar render paths to cut render cascades, memory churn, and UI jank on large sessions and big session trees. Behavior is preserved; the changes are about *when* and *how much* the UI re-renders. ## Chat streaming - Freeze the streaming message's parts in the bulk turn projection during streaming, and re-inject live parts only in an isolated tail leaf, so a ~60/sec delta stream no longer re-runs the whole-session projection or re-renders unrelated rows. session with referential reuse of unchanged turns. - Memoize message rows with field-aware comparators instead of reference equality. - Replace the manual child-session polling in the task tool with the live SSE stream + a one-shot load, removing a fetch/settle state machine. ## History loading & scroll - Load an initial page fast, then prepend one older page in the background so the scroll container has headroom and "load older on scroll-up" fires before the user hits the absolute top. - Compensate scroll synchronously (in a layout effect, before paint) for prepends — including background prepends that don't originate from a user scroll — so the viewport stays stable instead of judder-correcting on the next frame. ## Markdown rendering - Render markdown synchronously *styled* on first paint (paragraphs, lists, code cards, tables, inline code) instead of raw escaped text; the async pass then only upgrades syntax-highlight colors. Eliminates the flash of full-width raw text. - Load KaTeX CSS eagerly with the main bundle instead of inside the lazy markdown chunk, avoiding a late stylesheet injection on first render. ## Sidebar - Hoist per-row recursive tree walks out of row comparators into per-group precomputed sets/keys; batch live-session lookups into a single map; add a group-level memo boundary. - Isolate rename drafts so per-keystroke typing doesn't repaint the row tree. ## Sync layer - Add a staleness guard so a slow message fetch can't repopulate a session the user navigated away from. - Throw on fetch failure for authoritative loaders so a transient blip can't read as an empty server response. ## Cleanup - Remove dead code (unused hooks, params, duplicated inline types) surfaced while reworking the above. ## Known issue - A rare, purely cosmetic first-paint width flash can still appear on large sessions; it has no behavioral or data impact and is tracked for a follow-up runtime trace.
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 # Chat Session Performance Plan
 ## Goal
 Reduce render cost and history-load latency when switching between chat sessions
 in `packages/ui/src/components/chat/`, especially on Windows desktop with
 projects that have a long-running chat history (50–500 messages per session,
 tool-heavy workloads where each tool call returns 10–200 KB of output).
 The plan is **strictly behavior-preserving**: every change keeps the visible
 behavior 1:1 with the current build. Differences are only in the cost of doing
 the work, not in the UX, layout, limits, persistence, or order of operations.
 The two scenarios this targets:
 - Switching between sessions in the sidebar (especially in/out of a session
  with a long history) — the main window currently blocks the main thread
  for 200–500 ms on first paint while `JSON.parse` + `materializeSessionSnapshots`
  + `projectTurnRecords` run synchronously over the full initial page.
 - Returning to a session you visited a few minutes ago — the in-memory LRU
  (`SESSION_MESSAGE_RECORDS_CACHE_MAX = 40` desktop) helps, but the second
  visit to a session outside that window still pays the full network + parse
  cost.
 A secondary goal is to avoid hammering the OpenCode server with large
 single-shot fetches; we want smaller, more frequent, deduped requests.
 ## Upstream context
 Before implementing, I scanned open/closed PRs for overlap and lessons:
 - **#1651 — "perf: migrate chat rendering to virtua"** (`b920fd6f`, MERGED).
  Already moved chat history to `virtua` virtualization with `bufferSize: 900`
  and `MESSAGE_LIST_VIRTUALIZE_THRESHOLD = 5`, plus deferred Prism highlight,
  mermaid/file annotation, table listeners, stable plugin lists. This plan
  builds on top of that.
 - **#1650 — "perf: instant startup via cache hydration + decoupled readiness"**
  (`c62f0d1c`, MERGED). Instant startup + decoupled readiness — orthogonal.
 - **#1503 — "fix(chat): do not force scroll in thinking block during streaming"**
  (OPEN). Scroll behaviour during streaming — not in our hot path.
 - **#1584 — "feat: improve long user message collapse, scrolling, and navigation"**
  (DRAFT). Touches long user messages; no direct conflict with this plan.
 - **#1621 — "feat: comprehensive scrolling and navigation improvements"**
  (DRAFT). Broad scroll/navigation PR; no direct conflict.
 - **#1282 — "Optimize large-session sidebar trees, switching UX, and chat
  scroll restore stability"** (CLOSED by maintainer). Introduced session-
  switching instability, selection/chat desync, optimistic transitions.
  Lesson: keep this plan focused on render-cost reduction and stable memoization;
  do NOT add optimistic transitions, backend search endpoints, scroll-
  restoration loops, or pagination on top of an unstable base.
 - **#1448 — "feat: implement unified multi-server sidebar"** (DRAFT). Rewrites
  large parts of `SessionSidebar`. Independent of this plan.
 There is currently NO open PR targeting the same render-cost or history-load
 problems for the chat panel. We can proceed without coordination.
 ## Current Architecture Notes
 ### Data flow on session switch
 1. `ChatContainer` subscribes to `currentSessionId` from `useSessionUIStore`.
 2. `useSessionMessageRecords(currentSessionId, directory)` reads from the
   directory-scoped sync store via `React.useSyncExternalStore`. Snapshot
   cache: `SESSION_MESSAGE_RECORDS_CACHE_MAX = 40` desktop, `4` vscode/mobile.
 3. `useChatTimelineController.turnWindowModel` is rebuilt via
   `buildTurnWindowModel(messages)` on first open of a session; cached per
   sessionId in module-level `turnModelCache` (max 30 desktop, 4 constrained).
 4. `MessageList.baseDisplayMessages` reverses + dedupes + normalizes each
   message via `getNormalizedMessageForDisplay` (per-message `WeakMap` cache).
 5. `useTurnRecords` projects turn records via `projectTurnRecords` (O(N) over
   messages + per-turn work for summary/activity/diffStats/changedFiles).
   `previousProjectionRef` stabilizes across re-renders, but there is no
   module-level projection cache — returning to a session after the component
   unmounts pays the full projection cost again.
 6. `useChatTimelineController` runs the `useLayoutEffect` on `[sessionId]`
   that resets `isLoadingOlder`, `pendingRevealWork`, `activeTurnId`.
 ### Render hot path (current cost map)
 - `ChatContainer` (990 lines) subscribes to the full directory `permission`
  and `question` records via `useDirectorySync((s) => s.permission ?? {})` and
  `useDirectorySync((s) => s.question ?? {})` (`ChatContainer.tsx:436-443`).
  Any `permission.asked` or `question.asked` event for any session in the
  same directory re-renders `ChatContainer` and re-runs the `permissionsMap` /
  `questionsMap` / `scopedSessionIds` / `sessionPermissions` / `sessionQuestions`
  / `sessionIsWorking` chain. Same for `useSessions(directory)` — every
  `session.updated` event for any session in the directory re-renders the
  container.
 - `MessageList.reviewTransferDirection` (`MessageList.tsx:1151`) does
  `useGlobalSessionsStore((state) => { const currentSession = state.activeSessions.find(...) })`
  — runs `find` + `some` over the entire global active list on every global
  store change.
 - `MessageList` already has a `useStableEvent(getAnimationHandlers)`,
  `useStableEvent(scrollToBottom)`, and a module-level `timelineCache` for
  the virtua cache snapshot — those are the right pattern, just not applied
  uniformly.
 - `ChatMessage` (1182 lines) is `React.memo`-wrapped with
  `areRenderRelevantMessagesEqual` plus `areRelevantTurnGroupingContextsEqual`.
  `MessageBody` (2121 lines) is NOT `React.memo`-wrapped but is only
  rendered through `MessageRow` → `ChatMessage` and only re-runs when
  `areRenderRelevantMessagesEqual` returns false.
 ### The 1.5 MB problem
 The OpenCode server (separate repo, `anomalyco/opencode`) responds to
 `GET /api/session/{sessionID}/message` with
 `Array<{ info: Message, parts: Part[] }>` (the v1 wire shape preserved in
 the v2 SDK). On a typical tool-heavy session of 150 messages, this array
 serializes to ~1.5 MB of JSON. The bulk is `ToolStateCompleted.output: string`
 (confirmed in `node_modules/.bun/@opencode-ai+sdk@1.17.7/.../types.gen.d.ts:357-373`).
 The OpenChamber web server (`packages/web/server/index.js:1115`) installs
 Express `compression()` middleware BEFORE the OpenCode proxy
 (`packages/web/server/lib/opencode/proxy.js`), so the response IS compressed
 on the way out (5x reduction on typical JSON, so ~300 KB on the wire). The
 proxy explicitly sets `accept-encoding: identity` (`proxy.js:629`) which is
 a no-op against the upstream OpenCode server (it has no compression
 middleware — `server.ts` uses raw `@effect/platform-node` NodeHttpServer).
 So the **wire cost is ~300 KB after gzip**, not 1.5 MB. The real cost is the
 **client-side main-thread blocking**:
 - `JSON.parse` on 1.5 MB of structured data: ~50–200 ms in V8.
 - `materializeSessionSnapshots`: O(N) sort/filter, ~10–20 ms for 150.
 - `projectTurnRecords`: O(N) with per-turn work (summary/activity/diffStats/
  changedFiles/indexes), ~30–100 ms for 150.
 - `useChatTimelineController.useLayoutEffect` re-resolves pending scroll
  requests and updates `historySignals` — fast but runs synchronously.
 Total main-thread block on first paint: **200–500 ms**. The user-perceived
 "long load" is mostly this.
 ### Limit constants (current)
 | Constant                              | Value                             | Location              | Purpose                                 |
 | ------------------------------------- | --------------------------------- | --------------------- | --------------------------------------- |
 | `INITIAL_MESSAGE_PAGE_SIZE`             | 150 (desktop), 30 (vscode/mobile) | `use-sync.ts:25-27`     | First page on session switch            |
 | `HISTORY_MESSAGE_PAGE_SIZE`             | 200                               | `use-sync.ts:28`        | Scroll-up pagination                    |
 | `MESSAGE_REFETCH_LIMIT`                 | 200                               | `session-actions.ts:27` | Refetch after revert/abort              |
 | `RECONNECT_MESSAGE_LIMIT`               | 30                                | `sync-context.tsx:193`  | Reconnect bootstrap                     |
 | `SESSION_MATERIALIZATION_MESSAGE_LIMIT` | 30                                | `sync-context.tsx:194`  | Materialize on `message.updated` recovery |
 | `DEFAULT_MESSAGE_LIMIT`                 | 200                               | `sessionTypes.ts:78`    | Declarative ceiling; not enforced       |
 For 99% of sessions, users read the latest 30–50 messages and rarely scroll
 beyond. The 150-initial / 200-history combination fetches ~3x more than the
 visible window on first paint.
 ### Already optimized (do not touch)
 - `MessageList` virtualization with `virtua` at threshold 5, bufferSize 900
  (PR #1651).
 - `MessageRow` / `ChatMessage` / `TurnBlock` `React.memo` with custom
  comparators.
 - `getNormalizedMessageForDisplay` per-message `WeakMap` cache.
 - `MarkdownRenderer` lazy-loaded via `lazyWithChunkRecovery`; Prism highlight
  and mermaid deferred (PR #1651).
 - `expandedToolsStateCache` and `collapsedToolsStateCache` module-level LRU
  bounded at 4000 (`ChatMessage.tsx:39-95`).
 - `aggregateLiveSessions` / `aggregateLiveSessionStatuses` bail via
  `areSessionListsEquivalent` and `areStatusMapsEquivalent`; consumed through
  `useLiveSyncSelector`.
 - `useStickyProjectHeaders` IntersectionObserver.
 - Targeted field cloning in `handleDirectoryEvent` (sync/DOCUMENTATION.md).
 - `turnModelCache` for `buildTurnWindowModel` (30 desktop, 4 vscode/mobile).
 - `timelineCache` for virtua snapshot (max 16 sessions).
 - `session-prefetch-cache` 15s TTL dedup of `syncSession` requests.
 - `syncSessionInflightByKey` for in-flight dedup.
 ## Proposed Architecture
 ### Bugfix Layer 0 — Fix rapid project-switch race in sidebar
 **Observed bug:** When connected from desktop to an OpenChamber server, with
 multiple trees in the sidebar and large sessions (~200k context), rapidly
 switching between recent sessions in different projects causes the focus to
 follow the **fetch completion order** instead of the user's final click. The
 sequence is: user clicks 1, then 2, then 3; UI briefly shows 3; when fetch 1
 finishes it jumps to 1; when fetch 2 finishes it jumps to 2; when fetch 3
 finishes it finally lands on 3.
 **Root cause:** `useProjectSessionSelection` (`useProjectSessionSelection.ts`)
 has auto-selection logic that runs when `activeProjectId` changes. Combined
 with uncancelled async fetches and cross-project store updates, stale fetch
 completions update the sidebar session lists, which re-triggers selection
 fallbacks and overwrites the user's explicit choice.
 **Fix — four parts:**
 1. **Layer 0a — Generation guard in `useEnsureSessionMessages`.**
   Track a per-hook generation counter. When the effect fires for a new
   `sessionID`, increment the generation. Ignore the result (do not apply
   store mutations) if the generation is stale by the time the async fetch
   completes.
 2. **Layer 0b — Generation guard in `syncSession` / `loadMessages`.**
   Add a module-level `Map<sessionKey, number>` tracking the latest requested
   generation per session. Before every store write inside `syncSession` and
   `loadMessages`, check that the request is still current. This prevents
   fetches 1 and 2 from mutating state after the user has already selected 3.
 3. **Layer 0c — Debounce `handleSessionSelect`.**
   In `useSessionActions.ts`, wrap the actual navigation in a short timeout
   (~80ms). The first click executes immediately; rapid subsequent clicks
   cancel the pending navigation and reschedule for the latest target. This
   coalesces 1→2→3 into a single `setCurrentSession(3)` call.
 4. **Layer 0d — Explicit-selection guard in `useProjectSessionSelection`.**
   Track the timestamp of the last explicit user selection. Suppress the
   auto-select fallback in the layout effect for ~500ms after an explicit
   click, so fallback logic never overwrites an active user choice.
 **Effect:** Rapid project switching becomes deterministic: the UI stays on the
 last clicked session and only loads its content. Stale fetches are silently
 ignored instead of fighting for focus.
 **Files:** `sync-context.tsx`, `use-sync.ts`, `useSessionActions.ts`,
 `useProjectSessionSelection.ts`.
 ---
 ### Layer 1 — Narrow subscriptions in ChatContainer
 **Problem:** `ChatContainer.tsx:436-443` subscribes to the **full directory**
 `permission` and `question` records. Any permission/question event for **any**
 session in the directory causes a ChatContainer re-render, even if the event
 is for an unrelated session. Same for `useSessions(directory)` at line 427
 — every `session.updated` event re-renders the container.
 There are already session-scoped hooks (`useSessionPermissions(sessionID)`,
 `useSessionQuestions(sessionID)` at `sync-context.tsx:2151,2165`), but they
 don't aggregate across descendant subagent sessions — which
 `collectVisibleSessionIdsForBlockingRequests` (`ChatContainer.tsx:458-464`)
 handles for the `sessionPermissions` / `sessionQuestions` / `sessionIsWorking`
 chain.
 **Fix:** Replace the broad directory reads with scoped subtree selectors. The
 subtree is the current session and all its descendant subagent sessions.
 Add to `sync-context.tsx`:
 - `useScopedSubtreeIds(sessionID: string | null, directory?: string): Set<string>`
  — returns the set of session IDs in the current subtree (current session +
  all descendants by `parentID`). Reference-stabilized: a new Set is only
  returned when the actual membership changes, using the same "compare
  contents, reuse reference" pattern as `areSessionListsEquivalent`.
 - `useScopedBlockingRequests(sessionID: string | null, directory: string, kind: 'permission' | 'question')`
  — combines `useScopedSubtreeIds` with the existing `useSessionPermissions` /
  `useSessionQuestions` patterns to return a flat array of blocking requests
  scoped to the subtree only.
 - `useParentSession(sessionID: string | null): Session | null` — returns
  the parent Session via a pre-computed `Map<sessionId, Session>` that only
  changes when the target session or its parent changes. Replaces the O(N)
  `.find()` at `ChatContainer.tsx:564`.
 `ChatContainer` then:
 - reads `useScopedBlockingRequests` instead of the full `allPermissions`/
  `allQuestions` → `permissionsMap` → `scopedSessionIds` → `sessionPermissions`
  / `sessionQuestions` chain.
 - reads `useParentSession` instead of `sessions.find(...)`.
 - stops subscribing to `useSessions(directory)` entirely (the subtree selectors
  provide all needed session data scoped to the active subtree).
 **Effect:** Third-party sessions in the same directory stop re-rendering
 ChatContainer. Streaming events for unrelated sessions no longer invalidate
 the chat's blocking-requests chain.
 **Files:** `ChatContainer.tsx`, `sync-context.tsx`.
 ---
 ### Layer 3 — Module-level projection cache
 **Problem:** `useTurnRecords` keeps `previousProjectionRef` for in-component
 stabilization, but a session that unmounts and remounts loses that ref. Full
 re-projection cost is paid every time you return to a session.
 **Fix:** Add a module-level LRU keyed by `sessionKey`. The cache key must
 capture the exact identity of the message list to avoid stale projections:
 ```ts
 // Includes: sessionKey, message count, last message id,
 // AND the count of parts on the last message (detects streaming deltas
 // that add parts to an existing message without changing id or count).
 type CacheKey = `${sessionKey}|${length}|${lastMessageId ?? ''}|${lastMessagePartCount ?? 0}`
 const projectionCache = new Map<CacheKey, { projection: TurnProjectionResult }>()
 ```
 Including `lastMessagePartCount` is critical: during streaming, new parts are
 appended to the same last message — the message ID and total message count
 stay the same, but the projection must be recomputed.
 Cap at the same limits as `turnModelCache` (30 desktop, 4 vscode/mobile)
 to bound memory.
 `useTurnRecords` consults the cache before running `projectTurnRecords`; on
 hit, returns the cached projection and refreshes LRU order; on miss, runs the
 full projection and writes the result.
 **Effect:** Returning to a session within the LRU window is zero projection
 work. Combined with `MessageList.timelineCache` (which already caches the
 virtua snapshot), the first paint after a remount is essentially "rebuild
 only what's strictly session-specific (resolvers, refs)".
 **Files:** `useTurnRecords.ts` (small extension) + new helper
 `lib/turns/turnProjectionCache.ts`.
 ---
 ### Layer 4a — Start message fetch synchronously in setCurrentSession
 **Problem:** `session-ui-store.setCurrentSession` currently only calls
 `setState` (Zustand). The actual message fetch is started by
 `ChatContainer.useEffect` at `ChatContainer.tsx:787-792`, which runs on the
 render AFTER the state update — adding one React commit cycle (~30–80 ms)
 of latency before the network request starts.
 **Fix:** Start the fetch directly from `setCurrentSession` on the same tick
 as the state update, using the existing imperative access layer.
 The approach uses `session-actions.ts`, which already has module-level refs
 (`_sdk`, `_childStores`, `_getDirectory` — `session-actions.ts:33-35`) set by
 SyncProvider at mount time. Add a `fetchMessagesForSession(sessionID: string)`
 function there that duplicates the core path from `useSync().syncSession`:
 checks the child store for existing messages, fetches from SDK if needed,
 calls `materializeSessionSnapshots`, and writes to the directory store.
 `setCurrentSession` then calls `fetchMessagesForSession(targetId)` immediately
 after `set({ currentSessionId: id, ... })`. The `syncSessionInflightByKey`
 in `use-sync.ts` doesn't cover this new path, so the function also uses the
 existing `_ensureMessagesLoading` Set in `sync-context.tsx` (line 2668) for
 dedup.
 The existing `ChatContainer.useEffect` at line 787 stays as a safety net for
 sessions restored from URL or other non-sidebar entry points.
 **Effect:** Fetch starts on the same tick as the state update, ~30–80 ms
 earlier than the current "wait for React commit → useEffect → fetch" path.
 **Files:** `session-ui-store.ts` (one new call in `setCurrentSession`),
 `session-actions.ts` (new `fetchMessagesForSession` function).
 ---
 ### Layer 5 — Small wins
 - **`reviewTransferDirection` pre-computed map.** In
  `MessageList.tsx:1151-1164`, replace
  `useGlobalSessionsStore((state) => state.activeSessions.find(...))` with
  a selector that reads a pre-computed `Map<sessionId, ReviewTransferDirection>`
  maintained by `useGlobalSessionsStore` (built once per active-sessions
  change, in the same reducer that updates `activeSessions`). Same selector
  shape from the component's perspective, but no `.find()` + `.some()` on
  every global store change.
 - **`parentSession` lookup.** Part of Layer 1 (see `useParentSession` hook
  above). The pre-computed `Map<sessionId, Session>` is maintained in
  `sync-context.tsx` and read via the hook, eliminating the O(N) `.find()`
  in `ChatContainer`.
 **Files:** `MessageList.tsx`, `useGlobalSessionsStore.ts`.
 ---
 ### Layer 6a — Reduce initial payload
 Lower the page sizes to match typical user reading patterns:
 - `INITIAL_MESSAGE_PAGE_SIZE`: 150 → 50 (desktop), 30 stays (vscode/mobile).
 - `HISTORY_MESSAGE_PAGE_SIZE`: 200 → 100.
 - `MESSAGE_REFETCH_LIMIT`: 200 → 100.
 - `DEFAULT_MESSAGE_LIMIT` in `sessionTypes.ts`: stays 200 (it's a ceiling,
  not a fetch target).
 **How the "load more" indicator still works with a smaller initial page:**
 `historyMeta` in ChatContainer is built from `sync.hasMore(currentSessionId)`,
 which reads `meta.current` (set immediately after the first `loadMessages`
 call, before the component renders). If the server returns a cursor,
 `sync.hasMore()` returns `true` → `historyMeta.complete = false` →
 `hasMoreAboveTurns = true` → scroll-up indicator appears correctly.
 The `messages.length >= defaultLimit` fallback is never reached in practice
 because `historyMeta` is populated before the first render of the chat.
 Effect on the 1.5 MB problem:
 - Initial fetch payload: 1.5 MB → ~500 KB parsed (50 messages).
 - JSON.parse cost: 100–200 ms → 30–70 ms.
 - projection cost: 30–100 ms → 10–30 ms.
 - Combined main-thread block: 200–500 ms → 50–150 ms.
 User cost: one extra round trip when scrolling past the 50th message. The
 scroll-triggered `loadMore` is already in place and is the right UX for "I
 want to see older messages" — the previous behavior of "fetch 150 and ignore
 100" was wasted work for the common case.
 **Files:** `use-sync.ts`, `session-actions.ts`.
 ---
 ### Layer 6b — Progressive mount
 `use-sync.syncSession` starts the initial 50-message page synchronously.
 After the first page resolves, if the cursor indicates more messages, a
 second fetch of `HISTORY_MESSAGE_PAGE_SIZE` (100 messages) is dispatched
 via `loadMessages(sessionID, { before: cursor, mode: "prepend" })` — the
 prepend mode already exists in `loadMessages` (`use-sync.ts:373`). This
 second page is non-blocking; the user sees the first 50 messages immediately.
 On the client side, `useTurnRecords` and `useChatTimelineController` must
 re-run projection when the prepended messages arrive. Two options:
 - **Simple:** Let the full re-projection run on the second page arrival
  (50→150 messages). With Layer 6a, projection of 150 messages is ~10–30 ms —
  fast enough that a one-time re-project on the second page is acceptable.
 - **Optimal:** Extend `updateTurnWindowModelIncremental` (currently handles
  only +1 message appends — `windowTurns.ts:76-84` checks
  `nextMessages.length !== previousMessages.length + 1`) to handle batch
  prepends. This requires:
  1. A new `updateTurnWindowModelBatchPrepend` that verifies the new messages
     are all prepended (all existing message references match at the tail)
     and projects only the new messages into turn windows.
  2. A corresponding `updateTurnProjectionIncremental` in `projectTurnRecords.ts`
     that merges the new turns into the existing projection.
  Because `updateTurnWindowModelIncremental` is designed for single-message
  streaming deltas (not batch prepends), this is non-trivial additional work.
  Given Layer 6a alone reduces the main-thread block to ~50–150 ms, start
  with the simple approach and measure before committing to the incremental
  path.
 **Net effect:** The first 50 messages mount within the same time as today
 (possibly faster, because parsing 500 KB < parsing 1.5 MB). The next 100
 arrive ~200–400 ms later. From the user's perspective, the chat becomes
 interactive immediately.
 **Files:** `use-sync.ts`, `ChatContainer.tsx` (small — no change to `loadMore` UX).
 ---
 ## What I do not propose to touch (and why)
 - `useChatAutoFollow` and the scroll-restoration logic in
  `useChatTimelineController` (the `prePrependScrollRef` / height-delta
  compensation). PR #1282 closed because of scroll-restore regressions;
  these are working and tested.
 - The event-pipeline coalescing and `message.part.delta` reducer path.
  Already correct (sync/DOCUMENTATION.md).
 - The Markdown renderer and Prism highlight deferral. PR #1651 already took
  the low-hanging fruit.
 - The `key={currentSessionId}` on `<ChatViewport>`. Forces a full remount,
  which is expensive, but a previous PR attempt (Layer 2 in the sidebar
  plan) regressed scroll/follow. Keeping the remount for now.
 - The OpenCode server response shape. It's in `anomalyco/opencode`, which
  AGENTS.md forbids us from touching.
 - The SDK's internal `JSON.parse` step. Replacing it with a streaming
  parser requires owning the fetch call (the SDK doesn't expose the
  `ReadableStream`), and the response is a single JSON array, not NDJSON —
  so streaming buys us the same "first N visible, rest in background"
  pattern that Layer 6b already implements.
 - Tool output lazy-load. Would need a server-side endpoint like
  `GET /api/session/{sid}/part/{partID}` that the OpenCode server does
  not currently provide.
 ## Expected effect
 - **Initial session switch on a 150-message tool-heavy session:**
  main-thread block 200–500 ms → 50–150 ms. ~3x faster.
 - **Wire payload on the same session:** 1.5 MB parsed → 500 KB parsed.
  After gzip, ~300 KB → ~100 KB.
 - **Returning to a session within the LRU window:** zero projection work
  (Layer 3), zero scroll-cache rebuild (existing `timelineCache`).
 - **Returning to a session outside the LRU window:** same as initial, but
  the 15s `session-prefetch-cache` TTL catches sessions visited twice in
  rapid succession.
 - **Server load:** the OpenCode server processes 1/3 the volume per
  session-switch, and the warm second page in Layer 6b is deduped
  against the inflight request. Strictly less load than today.
 ## Files Touched by the Plan
 - `CHAT_PERF_PLAN.md` (new, this file)
 - `packages/ui/src/sync/sync-context.tsx` (Bugfix Layer 0a — `useEnsureSessionMessages` guard)
 - `packages/ui/src/sync/use-sync.ts` (Bugfix Layer 0b — `syncSession`/`loadMessages` guard; Layer 6a — constants)
 - `packages/ui/src/components/session/sidebar/hooks/useSessionActions.ts` (Bugfix Layer 0c — debounce)
 - `packages/ui/src/components/session/sidebar/hooks/useProjectSessionSelection.ts` (Bugfix Layer 0d — explicit-selection guard)
 - `packages/ui/src/components/chat/ChatContainer.tsx` (Layers 1, 6b)
 - `packages/ui/src/components/chat/MessageList.tsx` (Layer 5a)
 - `packages/ui/src/stores/useGlobalSessionsStore.ts` (Layer 5a — pre-computed map)
 - `packages/ui/src/sync/sync-context.tsx` (Layer 1 — new hooks: `useScopedSubtreeIds`, `useScopedBlockingRequests`, `useParentSession`)
 - `packages/ui/src/sync/session-ui-store.ts` (Layer 4a — call fetch from `setCurrentSession`)
 - `packages/ui/src/sync/session-actions.ts` (Layer 4a — new `fetchMessagesForSession`, Layer 6a — constants)
 - `packages/ui/src/sync/use-sync.ts` (Layer 6a — constants, Layer 6b — progressive fetch)
 - `packages/ui/src/stores/types/sessionTypes.ts` (Layer 6a — sync `DEFAULT_MESSAGE_LIMIT` with new constants)
 - `packages/ui/src/components/chat/hooks/useTurnRecords.ts` (Layer 3 — projection cache)
 - `packages/ui/src/components/chat/lib/turns/turnProjectionCache.ts` (new, Layer 3)
 ## Implementation order
 1. **Bugfix Layer 0** (race condition fixes) — highest priority, fixes the
   observed sidebar switching bug before any optimization work.
 2. **Layer 6a** (reduce constants) — simplest performance win, also reduces
   the race window.
 3. **Layer 3** (projection cache) — isolated change, immediate return-visit win.
 4. **Layer 5a** (reviewTransfer map) — isolated, low risk.
 5. **Layer 1** (narrow subscriptions) — more complex but well-bounded.
 6. **Layer 4a** (early fetch) — depends on Layer 1 for dedup safety.
 7. **Layer 6b** (progressive mount) — highest complexity, implement after
   measuring real-world gains from 6a.
 ## Conflict risks
 - None of the open PRs touch the files above in a conflicting way. PR #1584
  (draft, long user message collapse) modifies `UserTextPart.tsx`, not the
  files we touch. PR #1621 (draft, comprehensive scrolling) modifies scroll
  and navigation components, not the chat data flow. PR #1448 (draft,
  unified multi-server sidebar) is for `SessionSidebar.tsx` and family, not
  the chat panel.
 - Existing internal benchmarks for `event-pipeline` are unaffected
  (Layers 1, 3, 4a, 5, 6 do not touch event coalescing or ordering).
 - `bun run type-check` and `bun run lint` must remain green.
 ## Open Questions
 1. **Layer 2 (drop `key={currentSessionId}` from `ChatViewport`):** explicitly
   out of scope per user. Revisit after the lower-risk layers ship.
 2. **Layer 7 (Web Worker for `JSON.parse` + materialize):** out of scope.
   The Layer 6a/6b combo should bring main-thread block to ~50–150 ms,
   which is acceptable. Revisit if real-user feedback still shows jank.
 3. **Layer 6b incremental projection for batch prepends:** start with the
   simple full-reproject-on-second-page approach (50→150 projection is
   ~10–30 ms post-Layer-6a). Only build the incremental path if benchmarks
   show the full reproject is still noticeable.
 4. **Layer 3 cache invalidation during streaming:** the `lastMessagePartCount`
   in the cache key catches part deltas on the last message. If the streaming
   model appends parts to a message that is NOT the last (e.g., tool output
   on a completed turn while a new turn is streaming), the cache would miss —
   which is correct (projection must re-run). Confirm this edge case during
   smoke testing.
@@ -1,53 +0,0 @@
 # Right Sidebar Performance Plan
 ## Status — DONE (PR #1674)
 ### P0 — Correctness / leak fixes
 - [x] **RightSidebar**: drop dead `useEffect` that re-nulled refs the resize handler already nulled; collapse redundant `width`/`minWidth`/`maxWidth` triple into `width` + the existing `--oc-right-sidebar-width` variable.
 - [x] **useUIStore**: clamp `setRightSidebarWidth` to `[MIN, MAX]`; simplify `setRightSidebarOpen` (22 lines → 12).
 - [x] **RightSidebarTabs / `useRightSidebarGitSync`**: takes right tab + main tab; only polls when the right git tab is the visible consumer AND the browser is online + visible. Replaces a poll that ran for the lifetime of any open sidebar.
 - [x] **GitView**: commit-files fetch refactored to `cancelled` + `Promise.all` (was a per-hash loop that could `setState` after unmount); `getRemoteUrl` and `refreshRemotes` gated on `cancelled` / `mountedRef`; new module-scoped `mountedRef` guards `setIsSettingIdentity` from firing after unmount.
 - [x] **GitView + `useGitmojiList`**: extract gitmoji fetch/cache into a hook with module-level inflight promise + subscribers Set; stale-while-revalidate from localStorage; `ensureLoaded()` for call-site-initiated hydration; `cancelled` flag on `setIsLoading` to avoid the React setState-after-unmount race.
 - [x] **ProjectNotesTodoPanel**: 400 ms notes debounce now cancels on blur (was double-saving); `persistProjectData` chained per project through a module-level `Map<projectId, Promise>` so a fast todo toggle racing the debounced save no longer hits the server in parallel; resize auto-adjust guards against same-value pings.
 ### P1 — Render fanout
 - [x] **RightSidebarTabs**: all three tab content components now always mounted with the `hidden` attribute. State and cache survive tab switches. When `activeMainTab === 'git'` (or `'context'`) the matching right tab is filtered out of the tab strip and a redirect effect snaps any persisted-but-now-hidden right tab to `'files'`. `onSelect` is now a type-guarded handler instead of `as RightTab`.
 - [x] **GitView**: 13 separate `useGitStore` action selectors collapsed into one `useShallow` block (one re-evaluation per store change instead of 13).
 - [x] **GitView**: new `isGitViewActive` flag (true when this instance is the visible consumer) gates the 7 live effects — load identities, fetch remote URL, refresh remotes, `ensureAll`, `sessionEvents.onGitRefreshHint`, worktree bootstrap poll, default-identity auto-apply. Hidden GitView instances no longer run these.
 - [x] **GitView**: `gitViewSnapshots` module-level Map is now backed by an LRU wrapper (cap 20) so per-directory draft snapshots cannot leak across hundreds of project switches. Removed the dead `unique.set` dedup in `changeEntries` — `GitStatus.files` is already unique by path.
 - [x] **SidebarFilesTree**: `statusByPath` `Map<path, FileStatus>` and `badgeByDir` `Map<dirPath, { modified, added }>` are precomputed once per `gitStatus` change. Tree render is O(1) per node instead of O(N) per node. `badgeByDir` walks each file's path segments and increments counters for every ancestor dir.
 - [x] **SidebarFilesTree**: `FileRow` wrapped in `React.memo` with a custom comparator. Context-menu open state moved INTO `FileRow` as local state — opening a menu in one row no longer re-renders siblings.
 - [x] **SidebarFilesTree**: `loadDirectory` accepts an `isCancelled` predicate; the batch-load effect for `expandedPaths` passes a stable predicate so per-dir fetches stop touching state once the effect tears down.
 - [x] **SidebarFilesTree**: module-level `fileTreeCacheByRoot` Map (LRU, cap 8 roots) hydrates `childrenByDir` / `loadErrorsByDir` / `loadedDirsRef` on mount or root change. Mirror effects write state back to the cache. Survives close-and-reopen of the right sidebar.
 ### Review fixes (post-review)
 - [x] **Blocker**: `inFlightDirsRef` leak — removed `isCancelled` guard from `finally` so inflight flag always cleans up. Re-expanding a cancelled directory correctly retries.
 - [x] **Non-blocker**: duplicate `RIGHT_SIDEBAR_MAX_WIDTH` — exported from `useUIStore`, imported in `RightSidebar`. Single source of truth.
 - [x] **Non-blocker**: `useRightSidebarGitSync` poll gating — verified `shouldPoll` already includes `rightTab === 'git'`. No code change needed.
 ## Files modified
 | File | Change |
 |------|--------|
 | `packages/ui/src/components/layout/RightSidebar.tsx` | Drop dead useEffect, collapse width props, import constants from store |
 | `packages/ui/src/components/layout/RightSidebarTabs.tsx` | Always-mount tabs, gated poll, redirect effect, type-guarded onSelect |
 | `packages/ui/src/components/layout/SidebarFilesTree.tsx` | Precomputed maps, React.memo(FileRow), isCancelled predicate, LRU cache |
 | `packages/ui/src/components/git/GitView.tsx` | Cancelled + Promise.all, isGitViewActive, useShallow, LRU snapshots |
 | `packages/ui/src/components/project/ProjectNotesTodoPanel.tsx` | Debounce cancel on blur, chained persistProjectData |
 | `packages/ui/src/stores/useUIStore.ts` | Clamp setRightSidebarWidth, simplify setRightSidebarOpen, export constants |
 | `packages/ui/src/hooks/useGitmojiList.ts` | **New** — module-level inflight + subscribers, localStorage cache |
 ## Architecture notes
 - The redirect effect snaps `rightSidebarTab` to `'files'` whenever `activeMainTab === 'git'`, so the right and main `GitView` instances are mutually exclusive — `isGitViewActive` cannot be true for both.
 - The 7 gated effects plus the `useRightSidebarGitSync` poll cover all cases where git state should advance: visible consumer fetches; the poll keeps the store warm when only the right git tab is visible.
 - The `loadDirectory` cancellation predicate prevents stale state writes in `try`/`catch`; the `finally` block always cleans up `inFlightDirsRef`.
 ## Out of scope (deferred)
 - Virtualization of `SidebarFilesTree` (large refactor; current precomputed maps already address the main bottlenecks).
 - Lazy plan titles (requires `openchamberConfig` schema changes).
 - Extracting remaining sub-views from `GitView` (large refactor, not perf-critical).
@@ -1,5 +1,7 @@
 import React from 'react';
 import type { Message, Part, Session } from '@opencode-ai/sdk/v2';
 import type { PermissionRequest } from '@/types/permission';
 import type { QuestionRequest } from '@/types/question';
 import { ChatInput } from './ChatInput';
 import { DraftPresetChips } from './DraftPresetChips';
@@ -23,14 +25,8 @@ import { useDeviceInfo } from '@/lib/device';
 import { Button } from '@/components/ui/button';
 import { OverlayScrollbar } from '@/components/ui/OverlayScrollbar';
 import { Icon } from "@/components/icon/Icon";
 import type { PermissionRequest } from '@/types/permission';
 import type { QuestionRequest } from '@/types/question';
 import { cn, formatDirectoryName } from '@/lib/utils';
 import { useProjectsStore } from '@/stores/useProjectsStore';
 import {
    collectVisibleSessionIdsForBlockingRequests,
    flattenBlockingRequests,
 } from './lib/blockingRequests';
 // New sync system imports
 import { useSessionUIStore } from '@/sync/session-ui-store';
@@ -38,22 +34,21 @@ import { useStreamingStore } from '@/sync/streaming';
 import {
    useSessionMessageCount,
    useSessionMessageRecords,
    useSessions,
    useDirectorySync,
    useSyncDirectory,
    useDirectorySync,
    useSessionStatus,
    useScopedBlockingPermissions,
    useScopedBlockingQuestions,
    useParentSession,
 } from '@/sync/sync-context';
 import { useSync } from '@/sync/use-sync';
 import { getSessionPrefetch, subscribeSessionPrefetch } from '@/sync/session-prefetch-cache';
 import { getSessionMaterializationStatus } from '@/sync/materialization';
 import { usePlanDetection } from '@/hooks/usePlanDetection';
 import { getAllSyncSessions } from '@/sync/sync-refs';
 import { useI18n } from '@/lib/i18n';
 import { isVSCodeRuntime } from '@/lib/desktop';
 const EMPTY_MESSAGES: Array<{ info: Message; parts: Part[] }> = [];
 const EMPTY_PERMISSIONS: PermissionRequest[] = [];
 const EMPTY_QUESTIONS: QuestionRequest[] = [];
 const IDLE_SESSION_STATUS = { type: 'idle' as const };
 const CHAT_FORCE_SCROLL_BOTTOM_EVENT = 'openchamber:chat-force-scroll-bottom';
 const DEFAULT_RETRY_MESSAGE = 'Quota limit reached. Retrying automatically.';
@@ -140,6 +135,7 @@ type ChatViewportProps = {
    isDesktopExpandedInput: boolean;
    isMobile: boolean;
    stickyUserHeader: boolean;
    directory?: string;
    scrollRef: React.RefObject<HTMLDivElement | null>;
    messageListRef: React.RefObject<MessageListHandle | null>;
    pendingRevealWork: boolean;
@@ -168,6 +164,7 @@ const ChatViewport = React.memo(({
    isDesktopExpandedInput,
    isMobile,
    stickyUserHeader,
    directory,
    scrollRef,
    messageListRef,
    pendingRevealWork,
@@ -235,6 +232,7 @@ const ChatViewport = React.memo(({
                            isLoadingOlder={isLoadingOlder}
                            scrollToBottom={scrollToBottom}
                            scrollRef={scrollRef}
                            directory={directory}
                        />
                        {(sessionQuestions.length > 0 || sessionPermissions.length > 0) && (
                            <div>
@@ -263,6 +261,7 @@ const ChatViewport = React.memo(({
        && prev.isDesktopExpandedInput === next.isDesktopExpandedInput
        && prev.isMobile === next.isMobile
        && prev.stickyUserHeader === next.stickyUserHeader
        && prev.directory === next.directory
        && prev.scrollRef === next.scrollRef
        && prev.messageListRef === next.messageListRef
        && prev.pendingRevealWork === next.pendingRevealWork
@@ -407,7 +406,10 @@ export const ChatContainer: React.FC<ChatContainerProps> = ({ autoOpenDraft = tr
        effectiveSessionDirectory,
    );
    // Messages from sync system
-    const sessionMessageRecords = useSessionMessageRecords(currentSessionId ?? '', effectiveSessionDirectory);
+    const sessionMessageRecords = useSessionMessageRecords(currentSessionId ?? '', effectiveSessionDirectory, {
        suspendPartUpdates: Boolean(streamingMessageId),
        suspendPartUpdatesForMessageId: streamingMessageId,
    });
    const sessionMessages = currentSessionId ? sessionMessageRecords : EMPTY_MESSAGES;
    const sessionPrefetchInfo = React.useSyncExternalStore(
        React.useCallback(
@@ -423,55 +425,18 @@ export const ChatContainer: React.FC<ChatContainerProps> = ({ autoOpenDraft = tr
        React.useCallback(() => undefined, []),
    );
    // Sessions from sync system
    const sessions = useSessions(effectiveSessionDirectory);
    // Plan detection - watches messages for plan creation and signals store
    usePlanDetection(currentSessionId ?? '', sessionMessages);
    // Session status from sync system
    const sessionStatusForCurrent = useSessionStatus(currentSessionId ?? '', effectiveSessionDirectory) ?? IDLE_SESSION_STATUS;
-    // Permissions & questions from sync system
+    // Scoped blocking requests — only subscribe to permissions/questions for
-    const allPermissions = useDirectorySync(
+    // the current session + descendant subagent sessions, not all sessions in
-        React.useCallback((s) => s.permission ?? {}, []),
+    // the directory.
-        effectiveSessionDirectory,
+    const sessionPermissions = useScopedBlockingPermissions(currentSessionId, effectiveSessionDirectory);
-    );
+    const sessionQuestions = useScopedBlockingQuestions(currentSessionId, effectiveSessionDirectory);
    const allQuestions = useDirectorySync(
        React.useCallback((s) => s.question ?? {}, []),
        effectiveSessionDirectory,
    );
    // Convert Record → Map for blockingRequests helpers
    const permissionsMap = React.useMemo(() => {
        const m = new Map<string, PermissionRequest[]>();
        for (const [k, v] of Object.entries(allPermissions)) m.set(k, v as PermissionRequest[]);
        return m;
    }, [allPermissions]);
    const questionsMap = React.useMemo(() => {
        const m = new Map<string, QuestionRequest[]>();
        for (const [k, v] of Object.entries(allQuestions)) m.set(k, v as QuestionRequest[]);
        return m;
    }, [allQuestions]);
    const scopedSessionIds = React.useMemo(
        () => collectVisibleSessionIdsForBlockingRequests(
            sessions.map((session) => ({ id: session.id, parentID: session.parentID })),
            currentSessionId,
        ),
        [sessions, currentSessionId],
    );
    const sessionPermissions = React.useMemo(() => {
        if (scopedSessionIds.length === 0) return EMPTY_PERMISSIONS;
        return flattenBlockingRequests(permissionsMap, scopedSessionIds);
    }, [permissionsMap, scopedSessionIds]);
    const sessionQuestions = React.useMemo(() => {
        if (scopedSessionIds.length === 0) return EMPTY_QUESTIONS;
        return flattenBlockingRequests(questionsMap, scopedSessionIds);
    }, [questionsMap, scopedSessionIds]);
    const sessionIsWorking = React.useMemo(() => {
        if (!currentSessionId || sessionPermissions.length > 0 || sessionQuestions.length > 0) {
            return false;
@@ -561,15 +526,7 @@ export const ChatContainer: React.FC<ChatContainerProps> = ({ autoOpenDraft = tr
        return project ? getProjectDisplayLabel(project) : null;
    }, [activeProjectId, newSessionDraft?.selectedProjectId, projects]);
-    const parentSession = React.useMemo(() => {
+    const parentSession = useParentSession(currentSessionId, effectiveSessionDirectory);
        if (!currentSessionId) return null;
        const current = sessions.find((session) => session.id === currentSessionId);
        const parentID = current?.parentID;
        if (!parentID) return null;
        return sessions.find((session) => session.id === parentID)
            ?? getAllSyncSessions().find((session) => session.id === parentID)
            ?? null;
    }, [currentSessionId, sessions]);
    const handleReturnToParentSession = React.useCallback(() => {
        if (!parentSession) return;
@@ -943,6 +900,7 @@ export const ChatContainer: React.FC<ChatContainerProps> = ({ autoOpenDraft = tr
                isDesktopExpandedInput={isDesktopExpandedInput}
                isMobile={isMobile}
                stickyUserHeader={stickyUserHeader}
                directory={effectiveSessionDirectory}
                scrollRef={scrollRef}
                messageListRef={messageListRef}
                pendingRevealWork={timelineController.pendingRevealWork}
@@ -74,6 +74,7 @@ import { sessionEvents } from '@/lib/sessionEvents';
 import { fetchResponseStyleInstruction } from '@/lib/responseStyle';
 import { wrapSystemReminder } from '@/lib/systemReminder';
 import { getSyncMessages } from '@/sync/sync-refs';
 import { EMPTY_REVERTED_MESSAGE_DOCK_STATE, buildRevertedMessageDockState, type RevertedMessageDockState } from './revertedMessageDockState';
 import { eventMatchesShortcut, getEffectiveShortcutCombo, normalizeCombo } from '@/lib/shortcuts';
 import { isSyntheticPart } from '@/lib/messages/synthetic';
 import {
@@ -89,11 +90,10 @@ import {
    buildAttachmentCitationText,
    findAttachmentCitationRanges,
 } from './attachmentCitations';
-import type { Message, Part } from '@opencode-ai/sdk/v2/client';
+import type { Part } from '@opencode-ai/sdk/v2/client';
 const MAX_VISIBLE_TEXTAREA_LINES = 8;
 const EMPTY_QUEUE: QueuedMessage[] = [];
 const EMPTY_MESSAGES: Message[] = [];
 const FILE_MENTION_TOKEN = /^@[^\s]+$/;
 // Single-line URL pasted over a selection becomes a markdown link.
 const PASTE_LINK_URL_PATTERN = /^(https?:\/\/|mailto:)\S+$/i;
@@ -363,34 +363,28 @@ const RevertedMessageDock: React.FC<RevertedMessageDockProps> = React.memo(({ se
    const [restoringId, setRestoringId] = React.useState<string | null>(null);
    const [forkingId, setForkingId] = React.useState<string | null>(null);
    const [collapsed, setCollapsed] = React.useState(true);
-    const revertMessageID = useDirectorySync(
+    const revertedStateRef = React.useRef<RevertedMessageDockState>(EMPTY_REVERTED_MESSAGE_DOCK_STATE);
    const revertedState = useDirectorySync(
        React.useCallback((state) => {
-            if (!sessionId) return undefined;
+            const next = buildRevertedMessageDockState(state, sessionId, revertedStateRef.current);
-            const session = state.session.find((item) => item.id === sessionId);
+            revertedStateRef.current = next;
-            return (session as { revert?: { messageID?: string } } | undefined)?.revert?.messageID;
+            return next;
        }, [sessionId]),
        directory,
    );
-    const sessionMessages = useDirectorySync(
+    const revertMessageID = revertedState.revertMessageID;
        React.useCallback((state) => (sessionId ? state.message[sessionId] ?? EMPTY_MESSAGES : EMPTY_MESSAGES), [sessionId]),
        directory,
    );
    const partsByMessage = useDirectorySync(React.useCallback((state) => state.part, []), directory);
    const userMessages = React.useMemo(
-        () => sessionMessages.filter((message): message is Message & { role: 'user' } => message.role === 'user'),
+        () => revertedState.records.map((record) => record.message),
-        [sessionMessages],
+        [revertedState],
    );
    const noTextContent = t('chat.revertPopover.noTextContent');
    const items = React.useMemo(() => {
        if (!revertMessageID) return [];
-        return userMessages
+        return revertedState.records.map((record) => ({
-            .filter((message) => message.id >= revertMessageID)
+            id: record.message.id,
-            .map((message) => ({
+            text: getRevertedPreview(record.parts, noTextContent),
-                id: message.id,
+        }));
-                text: getRevertedPreview(partsByMessage[message.id] ?? [], noTextContent),
+    }, [noTextContent, revertMessageID, revertedState]);
            }));
    }, [noTextContent, partsByMessage, revertMessageID, userMessages]);
    const firstRevertedMessageId = items[0]?.id;
    React.useEffect(() => {
@@ -1,5 +1,4 @@
 import React from 'react';
 import 'katex/dist/katex.min.css';
 import morphdom from 'morphdom';
 import { renderMermaidASCII, renderMermaidSVG } from 'beautiful-mermaid';
 import type { Part } from '@opencode-ai/sdk/v2';
@@ -19,7 +18,7 @@ import type { EditorAPI } from '@/lib/api/types';
 import { isDesktopLocalOriginActive, isDesktopShell, isVSCodeRuntime } from '@/lib/desktop';
 import { ensureOutsideFileGrantForDesktop } from '@/lib/outsideFileGrants';
 import { getDirectoryForFilePath, isAbsoluteFilePath, isFilePathWithinDirectory, normalizeFilePath, toAbsoluteFilePath } from '@/lib/path-utils';
-import { fallbackHtml, renderMarkdownBlocks } from './markdown/markdownCore';
+import { renderMarkdownBlocks, renderMarkdownSync } from './markdown/markdownCore';
 import { ensureMarkdownShikiTheme, getMarkdownSyntaxVars } from './markdown/markdownTheme';
 import {
  attachMarkdownInteractions,
@@ -1032,10 +1031,16 @@ const useMorphdomMarkdown = ({
      // `display:contents` keeps margin-collapsing/spacing identical to a flat
      // HTML body — the wrapper exists only for per-block reconciliation.
      block.style.display = 'contents';
-      block.innerHTML = fallbackHtml(text);
+      block.innerHTML = renderMarkdownSync(text);
      // Decorate synchronously too: wrap code blocks in their framed card,
      // mark inline code, build table controls, etc. The async pass re-decorates
      // its own DOM before morphing, so without this the first paint shows bare
      // <pre>/tables that "snap" into their decorated form a tick later. Matching
      // the structure here keeps the async morph to syntax colors only.
      decorateMarkdown(block, ctx);
      target.appendChild(block);
    }
-  }, [containerRef, text]);
+  }, [containerRef, text, ctx]);
  React.useEffect(() => {
    const container = containerRef.current;
@@ -6,19 +6,19 @@ import ChatMessage from './ChatMessage';
 import { areOptionalRenderRelevantMessagesEqual, areRelevantTurnGroupingContextsEqual, areRenderRelevantMessagesEqual } from './message/renderCompare';
 import TurnItem from './components/TurnItem';
 import type { AnimationHandlers, ContentChangeReason } from '@/hooks/useChatAutoFollow';
 import { filterSyntheticParts } from '@/lib/messages/synthetic';
 import type { ChatMessageEntry, TurnRecord, TurnGroupingContext } from './lib/turns/types';
 import { useTurnRecords } from './hooks/useTurnRecords';
 import { applyRetryOverlay } from './lib/turns/applyRetryOverlay';
 import { buildLiveStreamingEntry } from './lib/turns/streamingTailEntry';
 import { getNormalizedMessageForDisplay, hasCompactionPart } from './lib/messageDisplayNormalization';
 import { useUIStore } from '@/stores/useUIStore';
 import { FadeInDisabledProvider } from './message/FadeInOnReveal';
 import { hasPendingUserSendAnimation, consumePendingUserSendAnimation } from '@/lib/userSendAnimation';
 import { streamPerfCount, streamPerfMeasure } from '@/stores/utils/streamDebug';
 import type { StreamPhase } from './message/types';
 import { normalizeParts } from './message/partUtils';
 import { useGlobalSessionsStore } from '@/stores/useGlobalSessionsStore';
-import { getReviewTransferDirection, type ReviewTransferDirection } from '@/lib/reviewFlow';
+import { useSessionParts } from '@/sync/sync-context';
-import { getOriginalSessionID, getReviewSessionID } from '@/lib/sessionReviewMetadata';
+import type { ReviewTransferDirection } from '@/lib/reviewFlow';
 const MESSAGE_LIST_VIRTUALIZE_THRESHOLD = 5;
 const EMPTY_STATIC_ENTRY_MESSAGES: ChatMessageEntry[] = [];
@@ -88,13 +88,6 @@ const resolveMessageRole = (message: ChatMessageEntry): string | null => {
        ?? null;
 };
 const hasCompactionPart = (message: ChatMessageEntry): boolean => {
    return message.parts.some((part) => {
        const type = (part as { type?: unknown } | null | undefined)?.type;
        return type === 'compaction';
    });
 };
 const getPartText = (part: Part): string => {
    const text = (part as { text?: unknown }).text;
    if (typeof text === 'string') {
@@ -107,40 +100,6 @@ const getPartText = (part: Part): string => {
    return '';
 };
 const normalizeCompactionCommandMessage = (message: ChatMessageEntry): ChatMessageEntry => {
    if (!hasCompactionPart(message)) {
        return message;
    }
    let changedParts = false;
    const nextParts = message.parts.map((part) => {
        const type = (part as { type?: unknown } | null | undefined)?.type;
        if (type !== 'compaction') {
            return part;
        }
        changedParts = true;
        return { type: 'text', text: '/compact' } as Part;
    });
    const info = message.info as unknown as { clientRole?: string | null | undefined };
    const needsClientRole = info.clientRole !== 'user';
    if (!changedParts && !needsClientRole) {
        return message;
    }
    return {
        ...message,
        info: needsClientRole
            ? ({
                ...(message.info as unknown as Record<string, unknown>),
                clientRole: 'user',
            } as unknown as typeof message.info)
            : message.info,
        parts: changedParts ? nextParts : message.parts,
    };
 };
 const normalizeCompactionSummaryMessage = (
    message: ChatMessageEntry,
    compactionCommandIds: Set<string>,
@@ -391,39 +350,6 @@ const withShellBridgeDetails = (message: ChatMessageEntry, details: ShellBridgeD
    };
 };
 const normalizeMessageParts = (message: ChatMessageEntry): ChatMessageEntry => {
    const parts = normalizeParts(message.parts);
    if (parts.length === message.parts.length) {
        return message;
    }
    return {
        ...message,
        parts,
    };
 };
 const normalizedMessageBySource = new WeakMap<ChatMessageEntry, ChatMessageEntry>();
 const getNormalizedMessageForDisplay = (message: ChatMessageEntry): ChatMessageEntry => {
    const cached = normalizedMessageBySource.get(message);
    if (cached) {
        return cached;
    }
    const normalizedPartMessage = normalizeMessageParts(message);
    const normalizedCompactionMessage = normalizeCompactionCommandMessage(normalizedPartMessage);
    const filteredParts = filterSyntheticParts(normalizedCompactionMessage.parts);
    const normalized = filteredParts === normalizedCompactionMessage.parts
        ? normalizedCompactionMessage
        : {
            ...normalizedCompactionMessage,
            parts: filteredParts,
        };
    normalizedMessageBySource.set(message, normalized);
    return normalized;
 };
 interface MessageListProps {
    sessionKey: string;
    disableStaging?: boolean;
@@ -442,6 +368,7 @@ interface MessageListProps {
    isLoadingOlder: boolean;
    scrollToBottom?: () => void;
    scrollRef?: React.RefObject<HTMLDivElement | null>;
    directory?: string;
 }
 export interface MessageListHandle {
@@ -1007,11 +934,10 @@ type StaticHistoryListProps = {
    chatRenderMode: 'sorted' | 'live';
    shouldAnimateUserMessage: (message: ChatMessageEntry) => boolean;
    onUserAnimationConsumed: (messageId: string) => void;
    activeStreamingPhase?: StreamPhase | null;
    reviewTransferDirection?: ReviewTransferDirection | null;
 };
-const StaticHistoryList = React.memo(({ entries, shouldVirtualize, contentRef, scrollRef, virtualizerRef, virtualizerKey, virtualCache, shift, onMessageContentChange, getAnimationHandlers, scrollToBottom, stickyUserHeader, defaultActivityExpanded, turnUiStates, onToggleTurnGroup, chatRenderMode, shouldAnimateUserMessage, onUserAnimationConsumed, activeStreamingPhase, reviewTransferDirection }: StaticHistoryListProps) => {
+const StaticHistoryList = React.memo(({ entries, shouldVirtualize, contentRef, scrollRef, virtualizerRef, virtualizerKey, virtualCache, shift, onMessageContentChange, getAnimationHandlers, scrollToBottom, stickyUserHeader, defaultActivityExpanded, turnUiStates, onToggleTurnGroup, chatRenderMode, shouldAnimateUserMessage, onUserAnimationConsumed, reviewTransferDirection }: StaticHistoryListProps) => {
    const renderEntry = React.useCallback((entry: RenderEntry) => {
        return (
            <MessageListEntry
@@ -1029,11 +955,11 @@ const StaticHistoryList = React.memo(({ entries, shouldVirtualize, contentRef, s
                shouldAnimateUserMessage={shouldAnimateUserMessage}
                onUserAnimationConsumed={onUserAnimationConsumed}
                activeStreamingMessageId={null}
-                activeStreamingPhase={activeStreamingPhase}
+                activeStreamingPhase={null}
                reviewTransferDirection={reviewTransferDirection}
            />
        );
-    }, [activeStreamingPhase, chatRenderMode, defaultActivityExpanded, getAnimationHandlers, onMessageContentChange, onToggleTurnGroup, onUserAnimationConsumed, reviewTransferDirection, scrollToBottom, shouldAnimateUserMessage, stickyUserHeader, turnUiStates]);
+    }, [chatRenderMode, defaultActivityExpanded, getAnimationHandlers, onMessageContentChange, onToggleTurnGroup, onUserAnimationConsumed, reviewTransferDirection, scrollToBottom, shouldAnimateUserMessage, stickyUserHeader, turnUiStates]);
    if (!shouldVirtualize) {
        return (
@@ -1074,6 +1000,7 @@ StaticHistoryList.displayName = 'StaticHistoryList';
 const StreamingTailContent: React.FC<{
    entry: RenderEntry;
    directory?: string;
    onMessageContentChange: (reason?: ContentChangeReason) => void;
    getAnimationHandlers: (messageId: string) => AnimationHandlers;
    scrollToBottom?: () => void;
@@ -1083,6 +1010,7 @@ const StreamingTailContent: React.FC<{
    turnUiStates: Map<string, TurnUiState>;
    onToggleTurnGroup: (turnId: string) => void;
    chatRenderMode: 'sorted' | 'live';
    showTurnChangedFiles: boolean;
    shouldAnimateUserMessage: (message: ChatMessageEntry) => boolean;
    onUserAnimationConsumed: (messageId: string) => void;
    activeStreamingMessageId?: string | null;
@@ -1090,6 +1018,7 @@ const StreamingTailContent: React.FC<{
    reviewTransferDirection?: ReviewTransferDirection | null;
 }> = ({
    entry,
    directory,
    onMessageContentChange,
    getAnimationHandlers,
    scrollToBottom,
@@ -1099,15 +1028,24 @@ const StreamingTailContent: React.FC<{
    turnUiStates,
    onToggleTurnGroup,
    chatRenderMode,
    showTurnChangedFiles,
    shouldAnimateUserMessage,
    onUserAnimationConsumed,
    activeStreamingMessageId,
    activeStreamingPhase,
    reviewTransferDirection,
 }) => {
    const liveParts = useSessionParts(activeStreamingMessageId ?? '', directory);
    const liveEntry = React.useMemo(() => buildLiveStreamingEntry(entry, {
        activeStreamingMessageId,
        liveParts,
        showTextJustificationActivity: chatRenderMode === 'sorted',
        showTurnChangedFiles,
    }), [activeStreamingMessageId, chatRenderMode, entry, liveParts, showTurnChangedFiles]);
    return (
        <MessageListEntry
-            entry={entry}
+            entry={liveEntry}
            onMessageContentChange={onMessageContentChange}
            getAnimationHandlers={getAnimationHandlers}
            scrollToBottom={scrollToBottom}
@@ -1141,6 +1079,7 @@ const MessageList = React.forwardRef<MessageListHandle, MessageListProps>(({
    isLoadingOlder,
    scrollToBottom,
    scrollRef,
    directory,
 }, ref) => {
    streamPerfCount('ui.message_list.render');
    const stickyUserHeader = useUIStore(state => state.stickyUserHeader);
@@ -1149,18 +1088,7 @@ const MessageList = React.forwardRef<MessageListHandle, MessageListProps>(({
    const showTurnChangedFiles = useUIStore((state) => state.showTurnChangedFiles);
    const defaultActivityExpanded = activityRenderMode === 'summary';
    const reviewTransferDirection = useGlobalSessionsStore((state) => {
-        const currentSession = state.activeSessions.find((session) => session.id === sessionKey);
+        return state.reviewTransferBySessionId.get(sessionKey) ?? null;
        const direction = getReviewTransferDirection(currentSession);
        if (!currentSession || !direction) return null;
        const targetSessionId = direction === 'review-to-original'
            ? getOriginalSessionID(currentSession)
            : getReviewSessionID(currentSession);
        if (!targetSessionId) return null;
        return state.activeSessions.some((session) => session.id === targetSessionId)
            ? direction
            : null;
    });
    const [turnUiStates, setTurnUiStates] = React.useState<Map<string, TurnUiState>>(() => new Map());
    const userAnimationRef = React.useRef<{
@@ -1665,12 +1593,12 @@ const MessageList = React.forwardRef<MessageListHandle, MessageListProps>(({
                            chatRenderMode={chatRenderMode}
                            shouldAnimateUserMessage={shouldAnimateUserMessage}
                            onUserAnimationConsumed={onUserAnimationConsumed}
                            activeStreamingPhase={activeStreamingPhase}
                            reviewTransferDirection={reviewTransferDirection}
                        />
                        {trailingStreamingEntry ? (
                            <StreamingTailContent
                                entry={trailingStreamingEntry}
                                directory={directory}
                                onMessageContentChange={stableTailContentChange}
                                getAnimationHandlers={stableGetAnimationHandlers}
                                scrollToBottom={stableScrollToBottom}
@@ -1680,6 +1608,7 @@ const MessageList = React.forwardRef<MessageListHandle, MessageListProps>(({
                                turnUiStates={turnUiStates}
                                onToggleTurnGroup={toggleTurnGroup}
                                chatRenderMode={chatRenderMode}
                                showTurnChangedFiles={showTurnChangedFiles}
                                shouldAnimateUserMessage={shouldAnimateUserMessage}
                                onUserAnimationConsumed={onUserAnimationConsumed}
                                activeStreamingMessageId={activeStreamingMessageId}
@@ -334,24 +334,67 @@ export const useChatTimelineController = ({
        return messageListRef.current?.restoreViewportAnchor(anchor) ?? false;
    }, [messageListRef]);
    // Tracks the timeline edges + height of the previous commit so a prepend
    // that did NOT go through fetchOlderHistory (e.g. the background history
    // prepend dispatched from useSync) can be compensated too. With
    // overflow-anchor:none the browser leaves scrollTop unchanged when content
    // is inserted above, so without this the viewport visibly jumps and
    // auto-follow yanks it back on the next frame — a one-shot up/down judder.
    const prependTrackingRef = React.useRef<{
        oldestId: string | null;
        newestId: string | null;
        scrollHeight: number;
    } | null>(null);
    React.useLayoutEffect(() => {
        const snap = prePrependScrollRef.current;
        const container = scrollRef.current;
-        if (!snap || !container) return;
+        if (!container) return;
        prePrependScrollRef.current = null;
-        // When a viewport anchor is available, delegate to MessageList
+        const snap = prePrependScrollRef.current;
-        // restoreViewportAnchor which falls back to virtualizer-aware
+        if (snap) {
-        // scrollHistoryIndexIntoView when the element is not in the DOM.
+            prePrependScrollRef.current = null;
-        if (snap.anchor && restoreViewportAnchor(snap.anchor)) {
+            // When a viewport anchor is available, delegate to MessageList
-            return;
+            // restoreViewportAnchor which falls back to virtualizer-aware
            // scrollHistoryIndexIntoView when the element is not in the DOM.
            if (!(snap.anchor && restoreViewportAnchor(snap.anchor))) {
                // Fallback: height-delta compensation
                const delta = container.scrollHeight - snap.height;
                if (delta > 0) {
                    container.scrollTop = snap.top + delta;
                }
            }
        } else {
            // Auto-detect a prepend: the oldest message changed while the newest
            // stayed the same (distinguishes a real prepend from a session
            // switch, a bottom append, or a streaming part growing). Compensate
            // synchronously by the exact height delta — for a bottom-pinned
            // viewport this keeps it pinned, for a released one it preserves the
            // read position, with no intermediate frame for auto-follow to fight.
            const prev = prependTrackingRef.current;
            const currentOldestId = renderedMessages[0]?.info?.id ?? null;
            const currentNewestId = renderedMessages[renderedMessages.length - 1]?.info?.id ?? null;
            const isPrepend = Boolean(
                prev
                && prev.oldestId
                && currentOldestId
                && currentOldestId !== prev.oldestId
                && prev.newestId
                && currentNewestId
                && currentNewestId === prev.newestId,
            );
            if (isPrepend && prev) {
                const delta = container.scrollHeight - prev.scrollHeight;
                if (delta > 0) {
                    container.scrollTop = container.scrollTop + delta;
                }
            }
        }
-        // Fallback: height-delta compensation
+        prependTrackingRef.current = {
-        const delta = container.scrollHeight - snap.height;
+            oldestId: renderedMessages[0]?.info?.id ?? null,
-        if (delta > 0) {
+            newestId: renderedMessages[renderedMessages.length - 1]?.info?.id ?? null,
-            container.scrollTop = snap.top + delta;
+            scrollHeight: container.scrollHeight,
-        }
+        };
    }, [renderedMessages, scrollRef, restoreViewportAnchor]);
    const revealBufferedTurns = React.useCallback(async (): Promise<boolean> => false, []);
@@ -1,6 +1,7 @@
 import React from 'react';
 import { projectTurnRecords } from '../lib/turns/projectTurnRecords';
 import type { ChatMessageEntry, TurnProjectionResult, TurnRecord } from '../lib/turns/types';
 import { buildProjectionCacheKey, getCachedProjection, setCachedProjection } from '../lib/turns/turnProjectionCache';
 import { streamPerfMeasure } from '@/stores/utils/streamDebug';
 interface UseTurnRecordsOptions {
@@ -46,6 +47,18 @@ export const useTurnRecords = (
    }, [options.sessionKey, options.showTextJustificationActivity, options.showTurnChangedFiles]);
    const projection = React.useMemo(() => {
        const sessionKey = options.sessionKey ?? '';
        const cached = getCachedProjection(
            sessionKey,
            messages,
            options.showTextJustificationActivity,
            options.showTurnChangedFiles,
        );
        if (cached) {
            previousProjectionRef.current = cached;
            return cached;
        }
        return streamPerfMeasure('ui.turns.projection_ms', () => {
            const nextProjection = projectTurnRecords(messages, {
                previousProjection: previousProjectionRef.current,
@@ -53,9 +66,18 @@ export const useTurnRecords = (
                showTurnChangedFiles: options.showTurnChangedFiles,
            });
            previousProjectionRef.current = nextProjection;
            const cacheKey = buildProjectionCacheKey(
                sessionKey,
                messages,
                options.showTextJustificationActivity,
                options.showTurnChangedFiles,
            );
            setCachedProjection(cacheKey, nextProjection);
            return nextProjection;
        });
-    }, [messages, options.showTextJustificationActivity, options.showTurnChangedFiles]);
+    }, [messages, options.showTextJustificationActivity, options.showTurnChangedFiles, options.sessionKey]);
    const staticTurns = React.useMemo(() => {
        const nextStatic = projection.turns.length <= 1
@@ -0,0 +1,79 @@
 import type { Part } from '@opencode-ai/sdk/v2';
 import { filterSyntheticParts } from '@/lib/messages/synthetic';
 import { normalizeParts } from '../message/partUtils';
 import type { ChatMessageEntry } from './turns/types';
 export const hasCompactionPart = (message: ChatMessageEntry): boolean => {
    return message.parts.some((part) => {
        const type = (part as { type?: unknown } | null | undefined)?.type;
        return type === 'compaction';
    });
 };
 const normalizeCompactionCommandMessage = (message: ChatMessageEntry): ChatMessageEntry => {
    if (!hasCompactionPart(message)) {
        return message;
    }
    let changedParts = false;
    const nextParts = message.parts.map((part) => {
        const type = (part as { type?: unknown } | null | undefined)?.type;
        if (type !== 'compaction') {
            return part;
        }
        changedParts = true;
        return { type: 'text', text: '/compact' } as Part;
    });
    const info = message.info as unknown as { clientRole?: string | null | undefined };
    const needsClientRole = info.clientRole !== 'user';
    if (!changedParts && !needsClientRole) {
        return message;
    }
    return {
        ...message,
        info: needsClientRole
            ? ({
                ...(message.info as unknown as Record<string, unknown>),
                clientRole: 'user',
            } as unknown as typeof message.info)
            : message.info,
        parts: changedParts ? nextParts : message.parts,
    };
 };
 const normalizeMessageParts = (message: ChatMessageEntry): ChatMessageEntry => {
    const parts = normalizeParts(message.parts);
    if (parts.length === message.parts.length) {
        return message;
    }
    return {
        ...message,
        parts,
    };
 };
 const normalizedMessageBySource = new WeakMap<ChatMessageEntry, ChatMessageEntry>();
 export const getNormalizedMessageForDisplay = (message: ChatMessageEntry): ChatMessageEntry => {
    const cached = normalizedMessageBySource.get(message);
    if (cached) {
        return cached;
    }
    const normalizedPartMessage = normalizeMessageParts(message);
    const normalizedCompactionMessage = normalizeCompactionCommandMessage(normalizedPartMessage);
    const filteredParts = filterSyntheticParts(normalizedCompactionMessage.parts);
    const normalized = filteredParts === normalizedCompactionMessage.parts
        ? normalizedCompactionMessage
        : {
            ...normalizedCompactionMessage,
            parts: filteredParts,
        };
    normalizedMessageBySource.set(message, normalized);
    return normalized;
 };
@@ -106,6 +106,27 @@ describe('projectTurnRecords', () => {
        expect(next.turns[1]).not.toBe(initial.turns[1]);
    });
    test('hydrates updated turns when a previous projection exists but no turn is reusable', () => {
        const user = createMessageEntry({ id: 'u1', role: 'user', createdAt: 1 });
        const assistant = createMessageEntry({ id: 'a1', role: 'assistant', parentID: 'u1', createdAt: 2 });
        const initial = projectTurnRecords([user, assistant]);
        const updatedAssistant = {
            ...assistant,
            parts: [{ id: 'tool_1', type: 'tool', tool: 'bash', state: { status: 'completed' } } as Part],
        };
        const next = projectTurnRecords([user, updatedAssistant], {
            previousProjection: initial,
        });
        expect(next.turns).toHaveLength(1);
        expect(next.turns[0]).not.toBe(initial.turns[0]);
        expect(next.turns[0]?.hasTools).toBe(true);
        expect(next.turns[0]?.activityParts).toHaveLength(1);
        expect(next.turns[0]?.stream.isStreaming).toBe(true);
        expect(next.turns[0]?.stream.isRetrying).toBe(false);
    });
    test('reuses the whole turns array when every turn is unchanged', () => {
        const user = createMessageEntry({ id: 'u1', role: 'user', createdAt: 1 });
        const assistant = createMessageEntry({ id: 'a1', role: 'assistant', parentID: 'u1', createdAt: 2 });
@@ -115,12 +115,43 @@ const canReusePreviousTurn = (previous: TurnRecord, next: TurnRecord): boolean =
        && areSameMessageRefs(previous.assistantMessages, next.assistantMessages);
 };
-const stabilizeTurnRecords = (
+const hydrateTurnRecord = (
    turn: TurnRecord,
    effectiveOptions: ProjectTurnRecordsOptions,
 ): TurnRecord => {
    turn.summary = projectTurnSummary(turn.assistantMessages);
    turn.summaryText = turn.summary.text ?? getUserSummaryBody(turn.userMessage);
    turn.diffStats = projectTurnDiffStats(turn.userMessage);
    turn.changedFiles = effectiveOptions.showTurnChangedFiles
        ? projectTurnChangedFiles(turn.userMessage)
        : undefined;
    const activity = projectTurnActivity({
        turnId: turn.turnId,
        assistantMessages: turn.assistantMessages,
        summarySourceMessageId: turn.summary.sourceMessageId,
        summarySourcePartId: turn.summary.sourcePartId,
        showTextJustificationActivity: effectiveOptions.showTextJustificationActivity,
    });
    turn.activityParts = activity.activityParts;
    turn.activitySegments = activity.activitySegments;
    turn.hasTools = activity.hasTools;
    turn.hasReasoning = activity.hasReasoning;
    turn.stream = buildTurnStreamState(turn.userMessage, turn.assistantMessages);
    turn.startedAt = turn.stream.startedAt;
    turn.completedAt = turn.stream.completedAt;
    turn.durationMs = turn.stream.durationMs;
    return turn;
 };
 const hydrateStableTurnRecords = (
    turns: TurnRecord[],
-    previousProjection?: TurnProjectionResult | null,
+    effectiveOptions: ProjectTurnRecordsOptions,
 ): TurnRecord[] => {
    const previousProjection = effectiveOptions.previousProjection;
    if (!previousProjection || previousProjection.turns.length === 0 || turns.length === 0) {
-        return turns;
+        return turns.map((turn) => hydrateTurnRecord(turn, effectiveOptions));
    }
    let canReuseTurnArray = previousProjection.turns.length === turns.length;
@@ -137,14 +168,14 @@ const stabilizeTurnRecords = (
        }
        canReuseTurnArray = false;
-        return turn;
+        return hydrateTurnRecord(turn, effectiveOptions);
    });
    if (canReuseTurnArray && reusedAnyTurn) {
        return previousProjection.turns;
    }
-    return reusedAnyTurn ? nextTurns : turns;
+    return nextTurns;
 };
 export const projectTurnRecords = (
@@ -214,33 +245,7 @@ export const projectTurnRecords = (
        groupedMessageIds.add(message.info.id);
    });
-    turns.forEach((turn) => {
+    const stableTurns = hydrateStableTurnRecords(turns, effectiveOptions);
        turn.summary = projectTurnSummary(turn.assistantMessages);
        turn.summaryText = turn.summary.text ?? getUserSummaryBody(turn.userMessage);
        turn.diffStats = projectTurnDiffStats(turn.userMessage);
        turn.changedFiles = effectiveOptions.showTurnChangedFiles
            ? projectTurnChangedFiles(turn.userMessage)
            : undefined;
        const activity = projectTurnActivity({
            turnId: turn.turnId,
            assistantMessages: turn.assistantMessages,
            summarySourceMessageId: turn.summary.sourceMessageId,
            summarySourcePartId: turn.summary.sourcePartId,
            showTextJustificationActivity: effectiveOptions.showTextJustificationActivity,
        });
        turn.activityParts = activity.activityParts;
        turn.activitySegments = activity.activitySegments;
        turn.hasTools = activity.hasTools;
        turn.hasReasoning = activity.hasReasoning;
        turn.stream = buildTurnStreamState(turn.userMessage, turn.assistantMessages);
        turn.startedAt = turn.stream.startedAt;
        turn.completedAt = turn.stream.completedAt;
        turn.durationMs = turn.stream.durationMs;
    });
    const stableTurns = stabilizeTurnRecords(turns, effectiveOptions.previousProjection);
    const projection = projectTurnIndexes(stableTurns);
    const ungroupedMessageIds = new Set<string>();
    messages.forEach((message) => {
@@ -0,0 +1,134 @@
 import { describe, expect, test } from 'bun:test';
 import type { Message, Part } from '@opencode-ai/sdk/v2';
 import { buildLiveStreamingEntry, type StreamingTailEntry } from './streamingTailEntry';
 import type { ChatMessageEntry, TurnRecord } from './types';
 const message = (id: string, role: 'user' | 'assistant', parentID?: string, parts: Part[] = []): ChatMessageEntry => ({
    info: {
        id,
        role,
        sessionID: 'ses_1',
        ...(parentID ? { parentID } : {}),
        time: { created: 1 },
    } as Message,
    parts,
 });
 const textPart = (id: string, text: string): Part => ({
    id,
    type: 'text',
    text,
 } as Part);
 const syntheticTextPart = (id: string, text: string): Part => ({
    id,
    type: 'text',
    text,
    synthetic: true,
 } as Part);
 const reasoningPart = (id: string, text: string): Part => ({
    id,
    type: 'reasoning',
    text,
 } as Part);
 const turnEntry = (assistant: ChatMessageEntry): StreamingTailEntry => {
    const user = message('user_1', 'user');
    return {
        kind: 'turn',
        key: 'turn:user_1',
        isLastTurn: true,
        turn: {
            turnId: 'user_1',
            userMessageId: 'user_1',
            userMessage: user,
            headerMessageId: assistant.info.id,
            messages: [],
            assistantMessageIds: [assistant.info.id],
            assistantMessages: [assistant],
            activityParts: [],
            activitySegments: [],
            summary: {},
            hasTools: false,
            hasReasoning: false,
            stream: { isStreaming: true, isRetrying: false },
        } satisfies TurnRecord,
    };
 };
 describe('buildLiveStreamingEntry', () => {
    test('returns the same entry when the active message is not in the tail', () => {
        const assistant = message('assistant_1', 'assistant', 'user_1', [textPart('part_1', 'old')]);
        const entry = turnEntry(assistant);
        const next = buildLiveStreamingEntry(entry, {
            activeStreamingMessageId: 'assistant_other',
            liveParts: [textPart('part_live', 'live')],
            showTextJustificationActivity: true,
            showTurnChangedFiles: false,
        });
        expect(next).toBe(entry);
    });
    test('rebuilds only the streaming turn with live parts', () => {
        const assistant = message('assistant_1', 'assistant', 'user_1', [textPart('part_1', 'hel')]);
        const entry = turnEntry(assistant);
        const liveParts = [reasoningPart('part_1_live', 'thinking')];
        const next = buildLiveStreamingEntry(entry, {
            activeStreamingMessageId: 'assistant_1',
            liveParts,
            showTextJustificationActivity: true,
            showTurnChangedFiles: false,
        });
        expect(next).not.toBe(entry);
        expect(next.kind).toBe('turn');
        if (next.kind !== 'turn') return;
        expect(next.turn.assistantMessages[0]?.parts).toBe(liveParts);
        expect(next.turn.activityParts.length).toBeGreaterThan(0);
    });
    test('updates an ungrouped streaming message with live parts', () => {
        const stale = message('assistant_1', 'assistant', undefined, [textPart('part_1', 'old')]);
        const entry: StreamingTailEntry = {
            kind: 'ungrouped',
            key: 'msg:assistant_1',
            message: stale,
        };
        const liveParts = [textPart('part_1_live', 'live')];
        const next = buildLiveStreamingEntry(entry, {
            activeStreamingMessageId: 'assistant_1',
            liveParts,
            showTextJustificationActivity: false,
            showTurnChangedFiles: false,
        });
        expect(next).not.toBe(entry);
        expect(next.kind).toBe('ungrouped');
        if (next.kind !== 'ungrouped') return;
        expect(next.message.parts).toBe(liveParts);
    });
    test('normalizes live tail parts with the display filtering path', () => {
        const stale = message('assistant_1', 'assistant', 'user_1', [textPart('part_1', 'old')]);
        const entry = turnEntry(stale);
        const visible = textPart('part_visible', 'visible');
        const synthetic = syntheticTextPart('part_synthetic', 'hidden while streaming');
        const next = buildLiveStreamingEntry(entry, {
            activeStreamingMessageId: 'assistant_1',
            liveParts: [synthetic, visible],
            showTextJustificationActivity: true,
            showTurnChangedFiles: false,
        });
        expect(next.kind).toBe('turn');
        if (next.kind !== 'turn') return;
        expect(next.turn.assistantMessages[0]?.parts).toEqual([visible]);
    });
 });
@@ -0,0 +1,86 @@
 import type { Part } from '@opencode-ai/sdk/v2';
 import { getNormalizedMessageForDisplay } from '../messageDisplayNormalization';
 import { projectTurnRecords } from './projectTurnRecords';
 import type { ChatMessageEntry, TurnRecord } from './types';
 export type StreamingTailEntry =
    | {
        kind: 'ungrouped';
        key: string;
        message: ChatMessageEntry;
        previousMessage?: ChatMessageEntry;
        nextMessage?: ChatMessageEntry;
    }
    | { kind: 'turn'; key: string; turn: TurnRecord; isLastTurn: boolean };
 type BuildLiveStreamingEntryOptions = {
    activeStreamingMessageId: string | null | undefined;
    liveParts: Part[];
    showTextJustificationActivity: boolean;
    showTurnChangedFiles: boolean;
 };
 const withLiveParts = (
    message: ChatMessageEntry,
    activeStreamingMessageId: string,
    liveParts: Part[],
 ): ChatMessageEntry => {
    if (message.info.id !== activeStreamingMessageId || message.parts === liveParts) {
        return message;
    }
    return getNormalizedMessageForDisplay({
        ...message,
        parts: liveParts,
    });
 };
 export const buildLiveStreamingEntry = <TEntry extends StreamingTailEntry>(
    entry: TEntry,
    options: BuildLiveStreamingEntryOptions,
 ): TEntry => {
    const activeStreamingMessageId = options.activeStreamingMessageId;
    if (!activeStreamingMessageId) {
        return entry;
    }
    if (entry.kind === 'ungrouped') {
        const message = withLiveParts(entry.message, activeStreamingMessageId, options.liveParts);
        if (message === entry.message) {
            return entry;
        }
        return {
            ...entry,
            message,
        };
    }
    let changed = false;
    const assistantMessages = entry.turn.assistantMessages.map((message) => {
        const next = withLiveParts(message, activeStreamingMessageId, options.liveParts);
        if (next !== message) {
            changed = true;
        }
        return next;
    });
    if (!changed) {
        return entry;
    }
    const projection = projectTurnRecords([entry.turn.userMessage, ...assistantMessages], {
        showTextJustificationActivity: options.showTextJustificationActivity,
        showTurnChangedFiles: options.showTurnChangedFiles,
    });
    const turn = projection.turns[0] ?? {
        ...entry.turn,
        assistantMessages,
        assistantMessageIds: assistantMessages.map((message) => message.info.id),
    };
    return {
        ...entry,
        turn,
    };
 };
@@ -0,0 +1,35 @@
 import { describe, expect, test } from 'bun:test';
 import type { Message, Part } from '@opencode-ai/sdk/v2';
 import { buildProjectionCacheKey } from './turnProjectionCache';
 import type { ChatMessageEntry } from './types';
 const createEntry = (text: string): ChatMessageEntry => ({
  info: { id: 'msg_1', role: 'assistant' } as Message,
  parts: [{ id: 'prt_1', type: 'text', text } as Part],
 });
 describe('turnProjectionCache', () => {
  test('keeps the cache key stable for unchanged message and part references', () => {
    const messages = [createEntry('hello')];
    const first = buildProjectionCacheKey('session_1', messages, false, false);
    const second = buildProjectionCacheKey('session_1', messages, false, false);
    expect(second).toBe(first);
  });
  test('changes the cache key when streaming replaces a part with the same id and count', () => {
    const before = [createEntry('hel')];
    const after = [
      {
        info: before[0].info,
        parts: [{ id: 'prt_1', type: 'text', text: 'hello' } as Part],
      },
    ];
    const beforeKey = buildProjectionCacheKey('session_1', before, false, false);
    const afterKey = buildProjectionCacheKey('session_1', after, false, false);
    expect(afterKey).not.toBe(beforeKey);
  });
 });
@@ -0,0 +1,86 @@
 import type { ChatMessageEntry, TurnProjectionResult } from './types';
 import { isVSCodeRuntime } from '@/lib/desktop';
 import { isMobileSurfaceRuntime } from '@/lib/runtimeSurface';
 const TURN_PROJECTION_CACHE_MAX = 30;
 const VSCODE_TURN_PROJECTION_CACHE_MAX = 4;
 const MOBILE_TURN_PROJECTION_CACHE_MAX = 4;
 const projectionCache = new Map<string, TurnProjectionResult>();
 const objectVersionByRef = new WeakMap<object, number>();
 let nextObjectVersion = 1;
 const getProjectionCacheMax = () => {
  if (isVSCodeRuntime()) return VSCODE_TURN_PROJECTION_CACHE_MAX;
  if (isMobileSurfaceRuntime()) return MOBILE_TURN_PROJECTION_CACHE_MAX;
  return TURN_PROJECTION_CACHE_MAX;
 };
 const getObjectVersion = (value: object): number => {
  const cached = objectVersionByRef.get(value);
  if (cached !== undefined) return cached;
  const next = nextObjectVersion;
  nextObjectVersion += 1;
  objectVersionByRef.set(value, next);
  return next;
 };
 const buildMessagesVersionSignature = (messages: ChatMessageEntry[]): string => {
  return messages.map((message) => {
    const infoVersion = getObjectVersion(message.info as object);
    const partsVersion = getObjectVersion(message.parts);
    const partVersions = message.parts.map((part) => getObjectVersion(part as object)).join(',');
    return `${infoVersion}:${partsVersion}:${partVersions}`;
  }).join(';');
 };
 export const buildProjectionCacheKey = (
  sessionKey: string,
  messages: ChatMessageEntry[],
  showTextJustificationActivity: boolean,
  showTurnChangedFiles: boolean,
 ): string => {
  const lastMessage = messages.length > 0 ? messages[messages.length - 1] : undefined;
  const lastMessageId = lastMessage?.info?.id ?? '';
  const lastMessagePartCount = lastMessage?.parts?.length ?? 0;
  return [
    sessionKey,
    messages.length,
    lastMessageId,
    lastMessagePartCount,
    buildMessagesVersionSignature(messages),
    showTextJustificationActivity ? '1' : '0',
    showTurnChangedFiles ? '1' : '0',
  ].join('|');
 };
 export const getCachedProjection = (
  sessionKey: string,
  messages: ChatMessageEntry[],
  showTextJustificationActivity: boolean,
  showTurnChangedFiles: boolean,
 ): TurnProjectionResult | undefined => {
  const key = buildProjectionCacheKey(sessionKey, messages, showTextJustificationActivity, showTurnChangedFiles);
  const cached = projectionCache.get(key);
  if (cached) {
    // LRU re-order: move hit to the end (most recent) so it survives
    // eviction longer than entries that haven't been read recently.
    projectionCache.delete(key);
    projectionCache.set(key, cached);
  }
  return cached;
 };
 export const setCachedProjection = (
  key: string,
  projection: TurnProjectionResult,
 ): void => {
  projectionCache.delete(key);
  const max = getProjectionCacheMax();
  while (projectionCache.size >= max) {
    const oldest = projectionCache.keys().next().value;
    if (typeof oldest !== 'string') break;
    projectionCache.delete(oldest);
  }
  projectionCache.set(key, projection);
 };
@@ -88,7 +88,11 @@ const decorateCodeBlocks = (root: HTMLElement, labels: DecorateLabels): void =>
    // Already wrapped (idempotent across morphdom passes).
    if (parent.closest('[data-component="markdown-code"]')) continue;
-    const language = pre.getAttribute('data-md-lang') ?? 'text';
+    // `data-md-lang` is stamped by the async highlight pass; on the synchronous
    // first paint it isn't set yet, so fall back to the `language-*` class marked
    // emits — keeps the card header label stable instead of flashing 'text'.
    const classLang = pre.querySelector('code')?.className.match(/language-([\w+#.-]+)/)?.[1];
    const language = pre.getAttribute('data-md-lang') ?? classLang ?? 'text';
    const wrapper = document.createElement('div');
    wrapper.setAttribute('data-component', 'markdown-code');
@@ -306,16 +306,6 @@ const sanitize = (html: string): string => {
  return DOMPurify.sanitize(html, SANITIZE_CONFIG) as unknown as string;
 };
 const escapeHtml = (text: string): string =>
  text
    .replace(/&/g, '&amp;')
    .replace(/</g, '&lt;')
    .replace(/>/g, '&gt;')
    .replace(/"/g, '&quot;')
    .replace(/'/g, '&#39;');
 export const fallbackHtml = (markdown: string): string =>
  escapeHtml(markdown).replace(/\r\n?/g, '\n').replace(/\n/g, '<br>');
 // ---------------------------------------------------------------------------
 // Per-block HTML cache (LRU, mirrors OpenCode's checksum cache)
@@ -349,6 +339,22 @@ const parseBlock = async (block: MarkdownBlock): Promise<string> => {
  return sanitize(highlighted);
 };
 /**
 * Synchronous styled render for the first paint, before the async pipeline
 * (Shiki-in-worker highlight) resolves. Produces the SAME structural HTML as
 * `renderMarkdownBlocks` minus syntax coloring: paragraphs, lists, code blocks
 * and bold all render at their final width, so the async pass only upgrades
 * code-block colors — no flash of full-width raw markdown source. `parser.parse`
 * is synchronous (marked is not configured `async`), so this never blocks on a
 * worker round-trip.
 */
 export const renderMarkdownSync = (text: string): string => {
  if (!text) return '';
  const parsed = parser.parse(text) as string;
  const withMath = renderMathExpressions(parsed);
  return sanitize(withMath);
 };
 export type RenderedBlock = {
  // Stable identity across renders for per-block DOM reconciliation. Encodes
  // content + mode + highlight so any change forces that block (and only that
@@ -12,11 +12,7 @@ import { useOptionalThemeSystem } from '@/contexts/useThemeSystem';
 import { useEffectiveDirectory } from '@/hooks/useEffectiveDirectory';
 import { useSessionUIStore } from '@/sync/session-ui-store';
 import { useDirectorySync, useSessionMessageRecords, useEnsureSessionMessages } from '@/sync/sync-context';
 import { getSyncChildStores } from '@/sync/sync-refs';
 import { useUIStore } from '@/stores/useUIStore';
 import { useSessionActivity } from '@/hooks/useSessionActivity';
 import { opencodeClient } from '@/lib/opencode/client';
 import { isVSCodeRuntime } from '@/lib/desktop';
 import { sessionEvents } from '@/lib/sessionEvents';
 import { ScrollShadow } from '@/components/ui/ScrollShadow';
 import { Button } from '@/components/ui/button';
@@ -164,17 +160,6 @@ const normalizeToolName = (toolName: string | undefined | null): string => {
 };
 const MAX_DURATION_MS = 5 * 60 * 1000; // 5 minutes cap
 const TASK_TOOL_POLL_FAST_MS = 1200;
 const TASK_TOOL_POLL_IDLE_MS = 3200;
 const TASK_TOOL_POLL_HIDDEN_MS = 6000;
 const TASK_TOOL_INITIAL_FETCH_LIMIT = 500;
 const TASK_TOOL_ACTIVE_FETCH_LIMIT = 160;
 const TASK_TOOL_IDLE_FETCH_LIMIT = 80;
 const VSCODE_TASK_TOOL_INITIAL_FETCH_LIMIT = 30;
 const VSCODE_TASK_TOOL_ACTIVE_FETCH_LIMIT = 30;
 const VSCODE_TASK_TOOL_IDLE_FETCH_LIMIT = 30;
 const TASK_TOOL_NO_CHANGE_BACKOFF_AFTER_POLLS = 3;
 const TASK_TOOL_SETTLE_GRACE_MS = 2500;
 const TASK_TOOL_FALLBACK_RETRY_MS = 3000;
 const GIT_REFRESH_MUTATING_TOOLS = new Set([
    'bash',
@@ -1025,41 +1010,6 @@ const buildTaskSummaryEntriesFromSession = (messages: SessionMessageWithParts[])
    return entries;
 };
 const buildTaskSessionMessagesSignature = (messages: SessionMessageWithParts[]): string => {
    if (!Array.isArray(messages) || messages.length === 0) {
        return '0';
    }
    const lastMessage = messages[messages.length - 1];
    const lastMessageId = typeof lastMessage?.info?.id === 'string' ? lastMessage.info.id : '';
    const lastMessageUpdated =
        typeof lastMessage?.info?.time?.completed === 'number'
            ? lastMessage.info.time.completed
            : typeof lastMessage?.info?.time?.created === 'number'
                ? lastMessage.info.time.created
                : 0;
    const lastParts = Array.isArray(lastMessage?.parts) ? lastMessage.parts : [];
    const lastPart = lastParts[lastParts.length - 1] as Record<string, unknown> | undefined;
    const tailType = typeof lastPart?.type === 'string' ? lastPart.type : '';
    const tailId = typeof lastPart?.id === 'string' ? lastPart.id : '';
    const tailTextLength = (() => {
        const textCandidate = lastPart?.text;
        if (typeof textCandidate === 'string') {
            return textCandidate.length;
        }
        const stateCandidate = lastPart?.state;
        if (stateCandidate && typeof stateCandidate === 'object') {
            const stateStatus = (stateCandidate as Record<string, unknown>).status;
            if (typeof stateStatus === 'string') {
                return stateStatus.length;
            }
        }
        return 0;
    })();
    return `${messages.length}:${lastMessageId}:${lastMessageUpdated}:${lastParts.length}:${tailType}:${tailId}:${tailTextLength}`;
 };
 const getTaskSummaryLabel = (entry: TaskToolSummaryEntry): string => {
    const title = entry.state?.title;
    if (typeof title === 'string' && title.trim().length > 0) {
@@ -1117,6 +1067,144 @@ const shouldRenderGitPathLabel = (toolName: string, label: string): boolean => {
    return /^[A-Za-z0-9_-]+$/.test(baseName);
 };
 const getTaskSummaryEntryRenderSignature = (entry: TaskToolSummaryEntry): string => {
    const toolName = normalizeToolName(entry.tool);
    const status = entry.state?.status ?? '';
    const label = getTaskSummaryLabel(entry);
    return `${entry.id ?? ''}\u0001${toolName}\u0001${status}\u0001${label}`;
 };
 const areTaskSummaryEntriesRenderEqual = (
    prevEntries: TaskToolSummaryEntry[],
    nextEntries: TaskToolSummaryEntry[],
 ): boolean => {
    if (prevEntries === nextEntries) return true;
    if (prevEntries.length !== nextEntries.length) return false;
    for (let index = 0; index < prevEntries.length; index += 1) {
        if (getTaskSummaryEntryRenderSignature(prevEntries[index]) !== getTaskSummaryEntryRenderSignature(nextEntries[index])) {
            return false;
        }
    }
    return true;
 };
 const TaskSummaryEntryRow = React.memo(({
    entry,
    isMobile,
    animateTailText,
    showToolFileIcons,
 }: {
    entry: TaskToolSummaryEntry;
    isMobile: boolean;
    animateTailText: boolean;
    showToolFileIcons: boolean;
 }) => {
    const normalizedToolName = normalizeToolName(entry.tool);
    const toolName = normalizedToolName.length > 0 ? normalizedToolName : 'tool';
    const label = getTaskSummaryLabel(entry);
    const hasLabel = label.trim().length > 0;
    const status = entry.state?.status;
    const displayName = getToolMetadata(toolName).displayName;
    return (
        <ToolRevealOnMount animate={animateTailText} wipe>
            <div className={cn('flex gap-2 min-w-0 w-full', isMobile ? 'items-start' : 'items-center')}>
                <span className="flex-shrink-0 text-foreground/80">{getToolIcon(toolName)}</span>
                <span
                    className="typography-meta text-foreground/80 flex-shrink-0"
                    style={{ color: 'var(--tools-title)' }}
                    title={displayName}
                >
                    {displayName}
                </span>
                {hasLabel ? (
                    status !== 'error' && shouldRenderGitPathLabel(toolName, label) ? (
                        renderAnimatedPathWithIcon(label, animateTailText, true, showToolFileIcons)
                    ) : (
                        status === 'error' ? (
                            <span className={cn(
                                'typography-meta flex-1 min-w-0 text-[var(--status-error)]',
                                isMobile ? 'whitespace-normal break-words' : 'truncate',
                            )}>
                                {label}
                            </span>
                        ) : (
                            <Text
                                variant={animateTailText ? 'generate-effect' : 'static'}
                                className={cn(
                                    'typography-meta flex-1 min-w-0 text-muted-foreground/70',
                                    isMobile ? 'whitespace-normal break-words' : 'truncate',
                                )}
                                style={{ color: 'var(--tools-description)' }}
                                title={label}
                            >
                                {label}
                            </Text>
                        )
                    )
                ) : null}
            </div>
        </ToolRevealOnMount>
    );
 }, (prev, next) => {
    return prev.isMobile === next.isMobile
        && prev.animateTailText === next.animateTailText
        && prev.showToolFileIcons === next.showToolFileIcons
        && getTaskSummaryEntryRenderSignature(prev.entry) === getTaskSummaryEntryRenderSignature(next.entry);
 });
 TaskSummaryEntryRow.displayName = 'TaskSummaryEntryRow';
 const TaskSummaryEntriesList = React.memo(({
    entries,
    isExpanded,
    isMobile,
    animateTailText,
    showToolFileIcons,
 }: {
    entries: TaskToolSummaryEntry[];
    isExpanded: boolean;
    isMobile: boolean;
    animateTailText: boolean;
    showToolFileIcons: boolean;
 }) => {
    const visibleEntries = isExpanded ? entries : entries.slice(-6);
    const hiddenCount = Math.max(0, entries.length - visibleEntries.length);
    const visibleStartIndex = entries.length - visibleEntries.length;
    return (
        <ToolScrollableSection maxHeightClass={isExpanded ? 'max-h-[40vh]' : 'max-h-56'} disableHorizontal>
            <div className="w-full min-w-0 space-y-1">
                {hiddenCount > 0 ? (
                    <div className="typography-micro text-muted-foreground/70">+{hiddenCount} more…</div>
                ) : null}
                {visibleEntries.map((entry, idx) => {
                    const absoluteIndex = isExpanded ? idx : visibleStartIndex + idx;
                    const rowKey = entry.id ?? `${getTaskSummaryEntryRenderSignature(entry)}:${absoluteIndex}`;
                    return (
                        <TaskSummaryEntryRow
                            key={rowKey}
                            entry={entry}
                            isMobile={isMobile}
                            animateTailText={animateTailText}
                            showToolFileIcons={showToolFileIcons}
                        />
                    );
                })}
            </div>
        </ToolScrollableSection>
    );
 }, (prev, next) => {
    return prev.isExpanded === next.isExpanded
        && prev.isMobile === next.isMobile
        && prev.animateTailText === next.animateTailText
        && prev.showToolFileIcons === next.showToolFileIcons
        && areTaskSummaryEntriesRenderEqual(prev.entries, next.entries);
 });
 TaskSummaryEntriesList.displayName = 'TaskSummaryEntriesList';
 const stripTaskMetadataFromOutput = (output: string): string => {
    // Strip only a trailing <task_metadata>...</task_metadata> block.
    return output.replace(/\n*<task_metadata>[\s\S]*?<\/task_metadata>\s*$/i, '').trimEnd();
@@ -1233,7 +1321,6 @@ const TaskToolSummary: React.FC<{
    const openContextPanelTab = useUIStore((state) => state.openContextPanelTab);
    const showToolFileIcons = useUIStore((state) => state.showToolFileIcons);
    const runtime = React.useContext(RuntimeAPIContext);
    const displayEntries = entries;
    const trimmedOutput = typeof output === 'string'
        ? stripTaskMetadataFromOutput(output)
@@ -1262,7 +1349,7 @@ const TaskToolSummary: React.FC<{
        ? input.subagent_type
        : 'subagent';
-    if (displayEntries.length === 0 && !hasOutput && !sessionId) {
+    if (entries.length === 0 && !hasOutput && !sessionId) {
        return (
            <div className="relative pr-2 pb-2 pt-2 space-y-2 pl-[1.4375rem]">
                <div className="typography-meta text-muted-foreground/70">
@@ -1272,9 +1359,6 @@ const TaskToolSummary: React.FC<{
        );
    }
    const visibleEntries = isExpanded ? displayEntries : displayEntries.slice(-6);
    const hiddenCount = Math.max(0, displayEntries.length - visibleEntries.length);
    return (
        <div
            className={cn(
@@ -1283,65 +1367,14 @@ const TaskToolSummary: React.FC<{
                'before:top-[-0.25rem] before:bottom-0'
            )}
        >
-            {displayEntries.length > 0 ? (
+            {entries.length > 0 ? (
-                <ToolScrollableSection maxHeightClass={isExpanded ? 'max-h-[40vh]' : 'max-h-56'} disableHorizontal>
+                <TaskSummaryEntriesList
-                    <div className="w-full min-w-0 space-y-1">
+                    entries={entries}
-                        {hiddenCount > 0 ? (
+                    isExpanded={isExpanded}
-                            <div className="typography-micro text-muted-foreground/70">+{hiddenCount} more…</div>
+                    isMobile={isMobile}
-                        ) : null}
+                    animateTailText={animateTailText}
-
+                    showToolFileIcons={showToolFileIcons}
-                        {visibleEntries.map((entry, idx) => {
+                />
                            const normalizedToolName = normalizeToolName(entry.tool);
                            const toolName = normalizedToolName.length > 0 ? normalizedToolName : 'tool';
                            const label = getTaskSummaryLabel(entry);
                            const hasLabel = label.trim().length > 0;
                            const status = entry.state?.status;
                            const displayName = getToolMetadata(toolName).displayName;
                            return (
                                <ToolRevealOnMount key={entry.id ?? `${toolName}-${idx}`} animate={animateTailText} wipe>
                                    <div className={cn("flex gap-2 min-w-0 w-full", isMobile ? 'items-start' : 'items-center')}>
                                        <span className="flex-shrink-0 text-foreground/80">{getToolIcon(toolName)}</span>
                                        <span
                                            className="typography-meta text-foreground/80 flex-shrink-0"
                                            style={{ color: 'var(--tools-title)' }}
                                            title={displayName}
                                        >
                                            {displayName}
                                        </span>
                                        {hasLabel ? (
                                            status !== 'error' && shouldRenderGitPathLabel(toolName, label) ? (
                                                renderAnimatedPathWithIcon(label, animateTailText, true, showToolFileIcons)
                                            ) : (
                                                status === 'error' ? (
                                                    <span className={cn(
                                                        'typography-meta flex-1 min-w-0 text-[var(--status-error)]',
                                                        isMobile ? 'whitespace-normal break-words' : 'truncate'
                                                    )}>
                                                        {label}
                                                    </span>
                                                ) : (
                                                    <Text
                                                        variant={animateTailText ? 'generate-effect' : 'static'}
                                                        className={cn(
                                                            'typography-meta flex-1 min-w-0 text-muted-foreground/70',
                                                            isMobile ? 'whitespace-normal break-words' : 'truncate'
                                                        )}
                                                        style={{ color: 'var(--tools-description)' }}
                                                        title={label}
                                                    >
                                                        {label}
                                                    </Text>
                                                )
                                            )
                                        ) : null}
                                    </div>
                                </ToolRevealOnMount>
                            );
                        })}
                    </div>
                </ToolScrollableSection>
            ) : null}
            {sessionId && (
@@ -1357,7 +1390,7 @@ const TaskToolSummary: React.FC<{
            )}
            {hasOutput ? (
-                <div className={cn('space-y-1', (displayEntries.length > 0 || sessionId) && 'pt-1')}
+                <div className={cn('space-y-1', (entries.length > 0 || sessionId) && 'pt-1')}
                >
                    <button
                        type="button"
@@ -2147,12 +2180,11 @@ const ToolPartContent: React.FC<ToolPartProps> = ({
                isTaskTool,
                parentSessionId: currentSessionId ?? undefined,
                taskStartTime: taskSessionResolutionStart,
                isTaskFinalized: isFinalized,
                sessions: storeState.session,
                sessionStatusMap: storeState.session_status,
                hasRetried: taskFallbackRetried,
            });
-        }, [explicitTaskSessionId, isTaskTool, currentSessionId, taskSessionResolutionStart, isFinalized, taskFallbackRetried]),
+        }, [explicitTaskSessionId, isTaskTool, currentSessionId, taskSessionResolutionStart, taskFallbackRetried]),
        currentDirectory,
    );
@@ -2172,49 +2204,7 @@ const ToolPartContent: React.FC<ToolPartProps> = ({
        return buildTaskSummaryEntriesFromSession(childSessionMessages);
    }, [childSessionMessages, isTaskTool, taskSessionId]);
    const childSessionHasInFlightTools = React.useMemo(() => {
        if (!isTaskTool || !taskSessionId || !Array.isArray(childSessionMessages) || childSessionMessages.length === 0) {
            return false;
        }
        for (const message of childSessionMessages) {
            if (message?.info?.role !== 'assistant') {
                continue;
            }
            const parts = Array.isArray(message.parts) ? message.parts : [];
            for (const childPart of parts) {
                if (childPart?.type !== 'tool') {
                    continue;
                }
                const childStatus =
                    typeof childPart === 'object' && childPart !== null && 'state' in childPart
                        ? (childPart.state as { status?: string } | undefined)?.status
                        : undefined;
                if (childStatus === 'running' || childStatus === 'pending' || childStatus === 'started') {
                    return true;
                }
            }
        }
        return false;
    }, [childSessionMessages, isTaskTool, taskSessionId]);
    const childSessionActivity = useSessionActivity(taskSessionId, currentDirectory);
    const [taskChildSeenActive, setTaskChildSeenActive] = React.useState(false);
    const [taskChildPollingStopped, setTaskChildPollingStopped] = React.useState(false);
    const [taskPendingFinalFetch, setTaskPendingFinalFetch] = React.useState(false);
    const taskPollNoChangeCountRef = React.useRef(0);
    const taskPollLastSignatureRef = React.useRef<string>('');
    const taskFinalFetchDoneRef = React.useRef(false);
    React.useEffect(() => {
        setTaskChildSeenActive(false);
        setTaskChildPollingStopped(false);
        setTaskPendingFinalFetch(false);
        taskPollNoChangeCountRef.current = 0;
        taskPollLastSignatureRef.current = '';
        taskFinalFetchDoneRef.current = false;
        setTaskFallbackRetried(false);
    }, [taskSessionId]);
@@ -2251,148 +2241,6 @@ const ToolPartContent: React.FC<ToolPartProps> = ({
        taskSessionResolutionStart,
    ]);
    React.useEffect(() => {
        if (hasFinalMetadataTaskSummary || !isTaskTool || !taskSessionId) {
            return;
        }
        const childSessionIsActive =
            childSessionActivity.phase === 'busy'
            || childSessionActivity.phase === 'retry'
            || childSessionHasInFlightTools;
        if (childSessionIsActive) {
            if (!taskChildSeenActive) {
                setTaskChildSeenActive(true);
            }
            if (taskChildPollingStopped) {
                setTaskChildPollingStopped(false);
            }
            if (taskPendingFinalFetch) {
                setTaskPendingFinalFetch(false);
            }
            return;
        }
        // Always stop polling if already done.
        if (taskChildPollingStopped && taskFinalFetchDoneRef.current) {
            return;
        }
        // Normal settle path: child went idle after we saw it active, and we have entries.
        // Schedule a grace period before marking polling as stopped.
        if (taskChildSeenActive && childSessionTaskSummaryEntries.length > 0 && !taskChildPollingStopped) {
            if (typeof window === 'undefined') {
                setTaskChildPollingStopped(true);
                return;
            }
            const timer = window.setTimeout(() => {
                setTaskChildPollingStopped(true);
            }, TASK_TOOL_SETTLE_GRACE_MS);
            return () => {
                window.clearTimeout(timer);
            };
        }
        // Final-fetch path: child went idle before parent saw it active, or we have no
        // entries yet. First stop polling after the settle grace period. A separate
        // effect performs the final fetch once polling has fully stopped, avoiding
        // races with any in-flight polling response.
        if (!taskChildPollingStopped && !taskFinalFetchDoneRef.current) {
            if (typeof window === 'undefined') {
                setTaskPendingFinalFetch(true);
                setTaskChildPollingStopped(true);
                return;
            }
            const timer = window.setTimeout(() => {
                setTaskPendingFinalFetch(true);
                setTaskChildPollingStopped(true);
            }, TASK_TOOL_SETTLE_GRACE_MS);
            return () => {
                window.clearTimeout(timer);
            };
        }
    }, [
        childSessionActivity.phase,
        childSessionHasInFlightTools,
        childSessionTaskSummaryEntries.length,
        currentDirectory,
        hasFinalMetadataTaskSummary,
        activeLatched,
        isFinalized,
        isTaskTool,
        taskPendingFinalFetch,
        taskChildPollingStopped,
        taskChildSeenActive,
        taskSessionId,
    ]);
    React.useEffect(() => {
        if (hasFinalMetadataTaskSummary || !isTaskTool || !taskSessionId || !taskChildPollingStopped || !taskPendingFinalFetch || taskFinalFetchDoneRef.current) {
            return;
        }
        let cancelled = false;
        const capturedSessionId = taskSessionId;
        const runFinalFetch = async () => {
            try {
                const scopedClient = opencodeClient.getScopedSdkClient(currentDirectory);
                const response = await scopedClient.session.messages({
                    sessionID: capturedSessionId,
                    limit: isVSCodeRuntime() ? VSCODE_TASK_TOOL_INITIAL_FETCH_LIMIT : TASK_TOOL_INITIAL_FETCH_LIMIT,
                });
                if (cancelled) {
                    return;
                }
                const messages = response.data ?? [];
                if (Array.isArray(messages) && messages.length > 0) {
                    const childStores = getSyncChildStores();
                    childStores.update(currentDirectory, (prev) => {
                        const records = messages as SessionMessageWithParts[];
                        const partPatch: Record<string, import('@opencode-ai/sdk/v2').Part[]> = { ...prev.part };
                        for (const rec of records) {
                            partPatch[rec.info.id] = rec.parts;
                        }
                        return {
                            message: { ...prev.message, [capturedSessionId]: records.map((r) => r.info) as import('@opencode-ai/sdk/v2').Message[] },
                            part: partPatch,
                        };
                    });
                }
                taskFinalFetchDoneRef.current = true;
                setTaskPendingFinalFetch(false);
            } catch {
                if (cancelled) {
                    return;
                }
                setTaskPendingFinalFetch(false);
                setTaskChildPollingStopped(false);
            }
        };
        void runFinalFetch();
        return () => {
            cancelled = true;
        };
    }, [
        currentDirectory,
        hasFinalMetadataTaskSummary,
        isTaskTool,
        taskChildPollingStopped,
        taskPendingFinalFetch,
        taskSessionId,
    ]);
    React.useEffect(() => {
        if (typeof time?.end === 'number' || typeof pinnedTime.end === 'number') {
            setLocalFinalizedAt(undefined);
@@ -2425,147 +2273,25 @@ const ToolPartContent: React.FC<ToolPartProps> = ({
        }
        return metadataTaskSummaryEntries;
    }, [childSessionTaskSummaryEntries, metadataTaskSummaryEntries]);
    const taskSummaryRenderSignature = React.useMemo(() => {
        return taskSummaryEntries.map(getTaskSummaryEntryRenderSignature).join('\u0000');
    }, [taskSummaryEntries]);
    const lastTaskSummaryRenderSignatureRef = React.useRef<string | null>(null);
    React.useEffect(() => {
        if (!isTaskTool || !taskSessionId) {
            return;
        }
        const childSessionActive = childSessionActivity.phase === 'busy' || childSessionActivity.phase === 'retry';
        if (hasFinalMetadataTaskSummary) {
            return;
        }
        const shouldPoll =
            !taskChildPollingStopped
            && (childSessionHasInFlightTools || childSessionActive || childSessionTaskSummaryEntries.length === 0);
        const shouldFetchSnapshot = !taskPendingFinalFetch && (childSessionTaskSummaryEntries.length === 0 || shouldPoll);
        if (!shouldFetchSnapshot) {
            return;
        }
        let cancelled = false;
        let pollTimer: number | undefined;
        const isVisible = () => {
            if (typeof document === 'undefined') {
                return true;
            }
            return document.visibilityState === 'visible';
        };
        const resolveFetchLimit = (isInitialFetch: boolean) => {
            if (isVSCodeRuntime()) {
                if (isInitialFetch && childSessionTaskSummaryEntries.length === 0) {
                    return VSCODE_TASK_TOOL_INITIAL_FETCH_LIMIT;
                }
                if (isActive || childSessionHasInFlightTools || childSessionActive) {
                    return VSCODE_TASK_TOOL_ACTIVE_FETCH_LIMIT;
                }
                return VSCODE_TASK_TOOL_IDLE_FETCH_LIMIT;
            }
            if (isInitialFetch && childSessionTaskSummaryEntries.length === 0) {
                return TASK_TOOL_INITIAL_FETCH_LIMIT;
            }
            if (isActive || childSessionHasInFlightTools || childSessionActive) {
                return TASK_TOOL_ACTIVE_FETCH_LIMIT;
            }
            return TASK_TOOL_IDLE_FETCH_LIMIT;
        };
        const resolvePollDelay = () => {
            if (!isVisible()) {
                return TASK_TOOL_POLL_HIDDEN_MS;
            }
            if (taskPollNoChangeCountRef.current >= TASK_TOOL_NO_CHANGE_BACKOFF_AFTER_POLLS) {
                return TASK_TOOL_POLL_IDLE_MS;
            }
            return TASK_TOOL_POLL_FAST_MS;
        };
        const scheduleNextPoll = () => {
            if (!shouldPoll || typeof window === 'undefined' || cancelled) {
                return;
            }
            pollTimer = window.setTimeout(() => {
                pollTimer = undefined;
                void fetchSessionMessages(false);
            }, resolvePollDelay());
        };
        const fetchSessionMessages = async (isInitialFetch: boolean) => {
            try {
                const scopedClient = opencodeClient.getScopedSdkClient(currentDirectory);
                const response = await scopedClient.session.messages({
                    sessionID: taskSessionId,
                    limit: resolveFetchLimit(isInitialFetch),
                });
                const messages = response.data ?? [];
                if (cancelled || !Array.isArray(messages) || messages.length === 0) {
                    return;
                }
                const nextSignature = buildTaskSessionMessagesSignature(messages as SessionMessageWithParts[]);
                if (nextSignature === taskPollLastSignatureRef.current) {
                    taskPollNoChangeCountRef.current += 1;
                    return;
                }
                taskPollLastSignatureRef.current = nextSignature;
                taskPollNoChangeCountRef.current = 0;
                // Inject fetched subagent messages into sync child store
                const childStores = getSyncChildStores();
                childStores.update(currentDirectory, (prev) => {
                    const records = messages as SessionMessageWithParts[];
                    const partPatch: Record<string, import('@opencode-ai/sdk/v2').Part[]> = { ...prev.part };
                    for (const rec of records) {
                        partPatch[rec.info.id] = rec.parts;
                    }
                    return {
                        message: { ...prev.message, [taskSessionId]: records.map((r) => r.info) as import('@opencode-ai/sdk/v2').Message[] },
                        part: partPatch,
                    };
                });
            } catch {
                // Ignore transient subagent fetch errors.
            } finally {
                scheduleNextPoll();
            }
        };
        void fetchSessionMessages(true);
        return () => {
            cancelled = true;
            if (typeof pollTimer === 'number') {
                window.clearTimeout(pollTimer);
            }
        };
    }, [
        childSessionActivity.phase,
        childSessionHasInFlightTools,
        childSessionTaskSummaryEntries.length,
        currentDirectory,
        hasFinalMetadataTaskSummary,
        isActive,
        isTaskTool,
        taskPendingFinalFetch,
        taskChildPollingStopped,
        taskSessionId,
    ]);
    const taskSummaryLenRef = React.useRef<number>(taskSummaryEntries.length);
    React.useEffect(() => {
        if (!isTaskTool) {
            lastTaskSummaryRenderSignatureRef.current = null;
            return;
        }
-        if (taskSummaryLenRef.current === taskSummaryEntries.length) {
+
        const previous = lastTaskSummaryRenderSignatureRef.current;
        lastTaskSummaryRenderSignatureRef.current = taskSummaryRenderSignature;
        if (previous === null || previous === taskSummaryRenderSignature || taskSummaryEntries.length === 0) {
            return;
        }
-        taskSummaryLenRef.current = taskSummaryEntries.length;
+
-        onContentChange?.('structural');
+        onContentChangeRef.current?.('structural');
-    }, [isTaskTool, onContentChange, taskSummaryEntries.length]);
+    }, [isTaskTool, taskSummaryEntries.length, taskSummaryRenderSignature]);
    const diffStats = React.useMemo(() => {
        return (normalizedPartTool === 'edit' || normalizedPartTool === 'multiedit' || normalizedPartTool === 'apply_patch')
@@ -31,13 +31,16 @@ describe('resolveFallbackTaskSessionId', () => {
    expect(result).toBeUndefined();
  });
-  it('returns undefined when task is finalized', () => {
+  it('returns undefined when multiple idle candidates are ambiguous', () => {
    const result = resolveFallbackTaskSessionId({
      isTaskTool: true,
      parentSessionId,
      taskStartTime,
-      sessions: [],
+      sessions: [
-      isTaskFinalized: true,
+        makeSession({ id: 'child-a', parentID: parentSessionId, time: { created: taskStartTime + 100 } }),
        makeSession({ id: 'child-b', parentID: parentSessionId, time: { created: taskStartTime + 200 } }),
      ],
      sessionStatusMap: {},
    });
    expect(result).toBeUndefined();
  });
@@ -29,8 +29,6 @@ export interface ResolveFallbackParams {
  parentSessionId: string | undefined;
  /** When the task tool started (ms timestamp) */
  taskStartTime: number | undefined;
  /** True when the task tool is finalized (completed/error/etc.) */
  isTaskFinalized?: boolean;
  /** Sessions from the directory store */
  sessions: Session[];
  /** Session status map from the sync store */
@@ -45,8 +43,8 @@ export interface ResolveFallbackParams {
 *
 * Returns `undefined` when:
 * - Not a task tool
 * - Task is finalized
 * - Parent session is unknown
 * - Task start time is unknown
 * - No unambiguous match found
 */
 export function resolveFallbackTaskSessionId(params: ResolveFallbackParams): string | undefined {
@@ -54,7 +52,6 @@ export function resolveFallbackTaskSessionId(params: ResolveFallbackParams): str
    isTaskTool,
    parentSessionId,
    taskStartTime,
    isTaskFinalized = false,
    sessions,
    sessionStatusMap,
    hasRetried = false,
@@ -64,6 +61,10 @@ export function resolveFallbackTaskSessionId(params: ResolveFallbackParams): str
    return undefined;
  }
  if (typeof taskStartTime !== 'number') {
    return undefined;
  }
  // Filter candidate sessions: parentID matches the current session.
  let candidates = sessions.filter((session) => {
    if (!session?.id || session.parentID !== parentSessionId) {
@@ -72,19 +73,14 @@ export function resolveFallbackTaskSessionId(params: ResolveFallbackParams): str
    return true;
  });
-  // When the task is still running, apply no time window — late-appearing
+  // Apply the time window even while running. Without it, a newly rendered task
-  // child sessions should still match. Once finalized, restrict to sessions
+  // can briefly bind to the previous child session before its own child exists.
-  // created within a generous window around the task start to avoid binding
+  const windowMs = hasRetried ? TASK_SESSION_MATCH_WINDOW_WIDE_MS : TASK_SESSION_MATCH_WINDOW_MS;
-  // to stale siblings. If taskStartTime is unavailable (cross-OpenCode
+  const latestAllowed = taskStartTime + windowMs;
-  // sessions), skip the time filter entirely.
+  candidates = candidates.filter((session) => {
-  if (typeof taskStartTime === 'number' && isTaskFinalized) {
+    const created = session.time?.created;
-    const windowMs = hasRetried ? TASK_SESSION_MATCH_WINDOW_WIDE_MS : TASK_SESSION_MATCH_WINDOW_MS;
+    return typeof created === 'number' && created >= taskStartTime && created <= latestAllowed;
-    const latestAllowed = taskStartTime + windowMs;
+  });
    candidates = candidates.filter((session) => {
      const created = session.time?.created;
      return typeof created === 'number' && created >= taskStartTime - 2_000 && created <= latestAllowed;
    });
  }
  if (candidates.length === 0) {
    return undefined;
@@ -105,18 +101,6 @@ export function resolveFallbackTaskSessionId(params: ResolveFallbackParams): str
    return liveCandidates[0].id;
  }
  // All idle: pick the most recently created child session.
  // This handles the common case where a delegation completed and the
  // user is viewing the task tool result inline.
  if (liveCandidates.length === 0 && candidates.length > 1) {
    const sorted = [...candidates].sort((a, b) => {
      const aCreated = typeof a.time?.created === 'number' ? a.time.created : 0;
      const bCreated = typeof b.time?.created === 'number' ? b.time.created : 0;
      return bCreated - aCreated;
    });
    return sorted[0].id;
  }
  // Ambiguous — do not guess
  return undefined;
 }
@@ -0,0 +1,89 @@
 import { describe, expect, test } from 'bun:test';
 import type { Message, Part } from '@opencode-ai/sdk/v2/client';
 import type { State } from '@/sync/types';
 import { EMPTY_REVERTED_MESSAGE_DOCK_STATE, buildRevertedMessageDockState } from './revertedMessageDockState';
 const message = (id: string, role: 'user' | 'assistant'): Message => ({
    id,
    role,
    sessionID: 'ses_1',
    time: { created: 1 },
 } as Message);
 const textPart = (id: string, text: string): Part => ({
    id,
    type: 'text',
    text,
 } as Part);
 const state = (partial: Partial<State>): Pick<State, 'session' | 'message' | 'part'> => ({
    session: [],
    message: {},
    part: {},
    ...partial,
 });
 describe('buildRevertedMessageDockState', () => {
    test('returns a shared empty state when the session is not reverted', () => {
        const first = buildRevertedMessageDockState(state({}), 'ses_1');
        const second = buildRevertedMessageDockState(
            state({ part: { assistant_1: [textPart('part_1', 'streaming')] } }),
            'ses_1',
            first,
        );
        expect(first).toBe(EMPTY_REVERTED_MESSAGE_DOCK_STATE);
        expect(second).toBe(EMPTY_REVERTED_MESSAGE_DOCK_STATE);
    });
    test('reuses the previous state when unrelated assistant parts change', () => {
        const user = message('user_1', 'user');
        const userParts = [textPart('part_user', 'hello')];
        const first = buildRevertedMessageDockState(
            state({
                session: [{ id: 'ses_1', revert: { messageID: 'user_1' } } as State['session'][number]],
                message: { ses_1: [user, message('assistant_1', 'assistant')] },
                part: { user_1: userParts, assistant_1: [textPart('part_a', 'a')] },
            }),
            'ses_1',
        );
        const second = buildRevertedMessageDockState(
            state({
                session: [{ id: 'ses_1', revert: { messageID: 'user_1' } } as State['session'][number]],
                message: { ses_1: [user, message('assistant_1', 'assistant')] },
                part: { user_1: userParts, assistant_1: [textPart('part_a2', 'updated')] },
            }),
            'ses_1',
            first,
        );
        expect(second).toBe(first);
    });
    test('updates when a reverted user message part changes', () => {
        const user = message('user_1', 'user');
        const first = buildRevertedMessageDockState(
            state({
                session: [{ id: 'ses_1', revert: { messageID: 'user_1' } } as State['session'][number]],
                message: { ses_1: [user] },
                part: { user_1: [textPart('part_user', 'hello')] },
            }),
            'ses_1',
        );
        const second = buildRevertedMessageDockState(
            state({
                session: [{ id: 'ses_1', revert: { messageID: 'user_1' } } as State['session'][number]],
                message: { ses_1: [user] },
                part: { user_1: [textPart('part_user_updated', 'updated')] },
            }),
            'ses_1',
            first,
        );
        expect(second).not.toBe(first);
        expect(second.records).toHaveLength(1);
    });
 });
@@ -0,0 +1,73 @@
 import type { Message, Part } from '@opencode-ai/sdk/v2/client';
 import type { State } from '@/sync/types';
 export type RevertedMessageRecord = {
    message: Message & { role: 'user' };
    parts: Part[];
 };
 export type RevertedMessageDockState = {
    revertMessageID?: string;
    records: RevertedMessageRecord[];
 };
 const EMPTY_PARTS: Part[] = [];
 const EMPTY_REVERTED_RECORDS: RevertedMessageRecord[] = [];
 export const EMPTY_REVERTED_MESSAGE_DOCK_STATE: RevertedMessageDockState = {
    revertMessageID: undefined,
    records: EMPTY_REVERTED_RECORDS,
 };
 const isUserMessage = (message: Message): message is Message & { role: 'user' } => {
    return message.role === 'user';
 };
 const areRecordsEqual = (left: RevertedMessageRecord[], right: RevertedMessageRecord[]): boolean => {
    if (left === right) return true;
    if (left.length !== right.length) return false;
    for (let index = 0; index < left.length; index += 1) {
        if (left[index]?.message !== right[index]?.message || left[index]?.parts !== right[index]?.parts) {
            return false;
        }
    }
    return true;
 };
 export const buildRevertedMessageDockState = (
    state: Pick<State, 'session' | 'message' | 'part'>,
    sessionId: string | null,
    previous: RevertedMessageDockState = EMPTY_REVERTED_MESSAGE_DOCK_STATE,
 ): RevertedMessageDockState => {
    if (!sessionId) {
        return EMPTY_REVERTED_MESSAGE_DOCK_STATE;
    }
    const session = state.session.find((item) => item.id === sessionId);
    const revertMessageID = (session as { revert?: { messageID?: string } } | undefined)?.revert?.messageID;
    if (!revertMessageID) {
        return EMPTY_REVERTED_MESSAGE_DOCK_STATE;
    }
    const messages = state.message[sessionId] ?? [];
    const records: RevertedMessageRecord[] = [];
    for (const message of messages) {
        if (!isUserMessage(message) || message.id < revertMessageID) {
            continue;
        }
        records.push({
            message,
            parts: state.part[message.id] ?? EMPTY_PARTS,
        });
    }
    const next = records.length === 0 ? EMPTY_REVERTED_RECORDS : records;
    if (previous.revertMessageID === revertMessageID && areRecordsEqual(previous.records, next)) {
        return previous;
    }
    return {
        revertMessageID,
        records: next,
    };
 };
@@ -3,6 +3,7 @@ import { cn } from '@/lib/utils';
 import type { SessionFolder } from '@/stores/useSessionFoldersStore';
 import { useI18n } from '@/lib/i18n';
 import { Icon } from "@/components/icon/Icon";
 import type { SessionNodeChildRenderExtras, SessionNodeRenderExtras } from './sidebar/sessionNodeItemUtils';
 interface SessionFolderItemProps<TSessionNode> {
  folder: SessionFolder;
@@ -19,7 +20,17 @@ interface SessionFolderItemProps<TSessionNode> {
    groupDir?: string | null,
    projectId?: string | null,
    archivedBucket?: boolean,
    secondaryMeta?: { projectLabel?: string | null; branchLabel?: string | null } | null,
    renderContext?: 'project' | 'recent',
    renderExtras?: SessionNodeChildRenderExtras,
  ) => React.ReactNode;
  /**
   * Returns the precomputed per-row render extras for a given node. The
   * group precomputes subtree-contains lookups once, then resolves a
   * per-node structure key here so SessionNodeItem's React.memo comparator
   * can answer with a single string compare instead of a recursive walk.
   */
  getRenderExtras?: (node: TSessionNode) => SessionNodeRenderExtras<TSessionNode> | undefined;
  groupDirectory?: string | null;
  projectId?: string | null;
  mobileVariant?: boolean;
@@ -54,6 +65,7 @@ const SessionFolderItemBase = <TSessionNode,>({
  onRename,
  onDelete,
  renderSessionNode,
  getRenderExtras,
  groupDirectory,
  projectId,
  mobileVariant = false,
@@ -320,7 +332,7 @@ const SessionFolderItemBase = <TSessionNode,>({
          {/* Then sessions */}
          {sessions.length > 0 ? (
            sessions.map((node) =>
-              renderSessionNode(node, 0, groupDirectory ?? null, projectId ?? null, archivedBucket),
+              renderSessionNode(node, 0, groupDirectory ?? null, projectId ?? null, archivedBucket, undefined, 'project', getRenderExtras?.(node)),
            )
          ) : !subFolderItems ? (
            <div className="py-1 pl-1.5 text-left typography-micro text-muted-foreground/70">
@@ -41,9 +41,11 @@ import { SidebarActivitySections } from './sidebar/SidebarActivitySections';
 import { SidebarFooter } from './sidebar/SidebarFooter';
 import { SidebarProjectsList } from './sidebar/SidebarProjectsList';
 import { SessionNodeItem } from './sidebar/SessionNodeItem';
 import type { SessionNodeRenderExtras } from './sidebar/sessionNodeItemUtils';
 import { useUpdateStore } from '@/stores/useUpdateStore';
 import { useShallow } from 'zustand/react/shallow';
 import { listProjectWorktrees } from '@/lib/worktrees/worktreeManager';
 import { checkIsGitRepository } from '@/lib/gitApi';
 import type { WorktreeMetadata } from '@/types/worktree';
 import type { SortableDragHandleProps } from './sidebar/sortableItems';
 import {
@@ -55,7 +57,7 @@ import {
  type DeleteSessionConfirmState,
 } from './sidebar/ConfirmDialogs';
 import { BulkActionBar } from './sidebar/BulkActionBar';
-import { useSessionMultiSelectStore } from '@/stores/useSessionMultiSelectStore';
+import { useSidebarBulkActions } from './sidebar/hooks/useSidebarBulkActions';
 import { useSessionDisplayStore } from '@/stores/useSessionDisplayStore';
 import { type SessionGroup, type SessionNode } from './sidebar/types';
 import {
@@ -153,6 +155,14 @@ const isKnownActiveSessionDirectory = (
 const SIDEBAR_PR_NO_PR_RETRY_MS = 5 * 60_000;
 const EMPTY_SUBTREE_SET: Set<string> = new Set();
 const useStableRenderCallback = <Args extends unknown[], Return>(handler: (...args: Args) => Return): ((...args: Args) => Return) => {
  const handlerRef = React.useRef(handler);
  handlerRef.current = handler;
  return React.useCallback((...args: Args) => handlerRef.current(...args), []);
 };
 interface SessionSidebarProps {
  mobileVariant?: boolean;
  onSessionSelected?: (sessionId: string) => void;
@@ -383,6 +393,16 @@ export const SessionSidebar: React.FC<SessionSidebarProps> = ({
    syncSessionsSnapshotRef.current = liveSessions;
  }, [syncSessionStructureSignature, liveSessions]);
  // Batched live-session index. Building this here turns the per-row
  // `useSession(session.id)` reads in SessionNodeItem (each of which
  // iterates all child-stores via `findLiveSession`) into a single
  // Map lookup. With M visible rows, that changes an O(M × child-stores)
  // work to O(child-stores) once per Sidebar render.
  const liveSessionById = React.useMemo(
    () => new Map(liveSessions.map((session) => [session.id, session] as const)),
    [liveSessions],
  );
  const projectWorktreeDiscoveryKey = React.useMemo(
    () => projects
      .map((project) => `${project.id}:${normalizePath(project.path) ?? ''}`)
@@ -399,6 +419,10 @@ export const SessionSidebar: React.FC<SessionSidebarProps> = ({
    void refreshGlobalSessions(syncSessionsSnapshotRef.current);
  }, []);
  // Tracks the last project list we already kicked off discovery for.
  // A re-mount with the same project set shouldn't fan out another
  // burst of `checkIsGitRepository` / `listProjectWorktrees` calls.
  const discoveredProjectsRef = React.useRef<string>('');
  React.useEffect(() => {
    let cancelled = false;
@@ -409,24 +433,39 @@ export const SessionSidebar: React.FC<SessionSidebarProps> = ({
      const worktreesByProject = new Map<string, WorktreeMetadata[]>();
      const allWorktrees: WorktreeMetadata[] = [];
-      await Promise.all(
+      // Constrain fanout: previously `Promise.all(projects.map(...))` could
-        projectEntries.map(async (project) => {
+      // spawn dozens of concurrent `git worktree list` and
      // `checkIsGitRepository` calls on cold start, each touching the
      // worktree process. Concurrency=3 keeps startup latency low while
      // bounding peak worktree-process load.
      const worktreeConcurrency = 3;
      let cursor = 0;
      const workers = Array.from({ length: worktreeConcurrency }, async () => {
        while (true) {
          const nextIndex = cursor;
          cursor += 1;
          if (nextIndex >= projectEntries.length) return;
          const project = projectEntries[nextIndex];
          const projectPath = normalizePath(project.path);
-          if (!projectPath) return;
+          if (!projectPath) continue;
          try {
-            // Use store-cached isGitRepo when available; fall back to direct check for initial worktree discovery
+            // Use store-cached isGitRepo when available; fall back to
            // a direct check for projects the Git store hasn't seen yet.
            // Forcing `ensureStatus` here also warms the store so the
            // PR/render paths downstream can read isGitRepo for free.
            const cachedIsGitRepo = useGitStore.getState().directories.get(projectPath)?.isGitRepo;
-            const isGitRepo = cachedIsGitRepo ?? await import('@/lib/gitApi').then(m => m.checkIsGitRepository(projectPath));
+            const isGitRepo = cachedIsGitRepo ?? await checkIsGitRepository(projectPath);
-            if (!isGitRepo) return;
+            if (!isGitRepo) continue;
            const worktrees = await listProjectWorktrees({ id: project.id, path: projectPath });
-            if (cancelled || worktrees.length === 0) return;
+            if (cancelled || worktrees.length === 0) continue;
            worktreesByProject.set(projectPath, worktrees);
            allWorktrees.push(...worktrees);
          } catch {
            // ignore discovery errors
          }
-        }),
+        }
-      );
+      });
      await Promise.all(workers);
      if (cancelled) return;
@@ -436,6 +475,11 @@ export const SessionSidebar: React.FC<SessionSidebarProps> = ({
      });
    };
    // Skip if we already discovered worktrees for this exact project set.
    if (discoveredProjectsRef.current === projectWorktreeDiscoveryKey) {
      return;
    }
    discoveredProjectsRef.current = projectWorktreeDiscoveryKey;
    void discoverWorktrees();
    return () => {
@@ -508,11 +552,29 @@ export const SessionSidebar: React.FC<SessionSidebarProps> = ({
    return [...sessions].sort((a, b) => compareSessionsByPinnedAndTime(a, b, pinnedSessionIds));
  }, [sessions, pinnedSessionIds]);
-  const sessionOrderIndex = React.useMemo(
+  // Stable signature: id + updatedAt joined. When this string is
-    () => new Map(sortedSessions.map((session, index) => [session.id, index])),
+  // unchanged, the relative ordering of sessions is identical and the
  // derived `sessionOrderIndex` Map can return the previous reference.
  // Without this, a fresh `sortedSessions` array (cheap to rebuild) would
  // still hand a new Map identity to the entire SessionGroupSection
  // memo chain, invalidating sourceGroupNodes, nodeBySessionId, and the
  // rest of the down-stream useMemo chain.
  const sessionOrderSignature = React.useMemo(
    () => sortedSessions.map((s) => `${s.id}:${s.time?.updated ?? 0}`).join('|'),
    [sortedSessions],
  );
  const sessionOrderIndexRef = React.useRef<{ signature: string; map: Map<string, number> } | null>(null);
  const sessionOrderIndex = React.useMemo(() => {
    const cached = sessionOrderIndexRef.current;
    if (cached && cached.signature === sessionOrderSignature) {
      return cached.map;
    }
    const next = new Map(sortedSessions.map((session, index) => [session.id, index]));
    sessionOrderIndexRef.current = { signature: sessionOrderSignature, map: next };
    return next;
  }, [sessionOrderSignature, sortedSessions]);
  const childrenMap = React.useMemo(() => {
    const map = new Map<string, Session[]>();
    sortedSessions.forEach((session) => {
@@ -703,6 +765,16 @@ export const SessionSidebar: React.FC<SessionSidebarProps> = ({
    [collapsedFolderIds, toggleFolderCollapse, createFolder, t],
  );
  const stableHandleSessionSelect = useStableRenderCallback(handleSessionSelect);
  const stableHandleSessionDoubleClick = useStableRenderCallback(handleSessionDoubleClick);
  const stableHandleSaveEdit = useStableRenderCallback(handleSaveEdit);
  const stableHandleCancelEdit = useStableRenderCallback(handleCancelEdit);
  const stableHandleShareSession = useStableRenderCallback(handleShareSession);
  const stableHandleCopyShareUrl = useStableRenderCallback(handleCopyShareUrl);
  const stableHandleUnshareSession = useStableRenderCallback(handleUnshareSession);
  const stableHandleDeleteSession = useStableRenderCallback(handleDeleteSession);
  const stableCreateFolderAndStartRename = useStableRenderCallback(createFolderAndStartRename);
  const showMoreGroupSessions = React.useCallback((groupId: string, currentVisibleCount: number) => {
    setVisibleSessionCountByGroup((prev) => {
      const next = new Map(prev);
@@ -881,6 +953,7 @@ export const SessionSidebar: React.FC<SessionSidebarProps> = ({
    sessions,
    archivedSessions,
    availableWorktreesByProject,
    normalizedProjects,
  });
  useArchivedAutoFolders({
@@ -930,7 +1003,7 @@ export const SessionSidebar: React.FC<SessionSidebarProps> = ({
    </div>
  );
-  const { currentSessionDirectory } = useProjectSessionSelection({
+  useProjectSessionSelection({
    projectSections,
    activeProjectId,
    activeSessionByProject,
@@ -942,8 +1015,6 @@ export const SessionSidebar: React.FC<SessionSidebarProps> = ({
    openNewSessionDraft,
    setActiveMainTab,
    setSessionSwitcherOpen,
    sessions,
    worktreeMetadata,
  });
  const { getOrderedGroups } = useGroupOrdering(groupOrderByProject);
@@ -1214,15 +1285,16 @@ export const SessionSidebar: React.FC<SessionSidebarProps> = ({
    projectHeaderSentinelRefs,
  });
-  const renderSessionNode = React.useCallback(
+  const renderSessionNode = useStableRenderCallback(
    (
      node: SessionNode,
-      depth = 0,
+      depth: number = 0,
      groupDirectory?: string | null,
      projectId?: string | null,
-      archivedBucket = false,
+      archivedBucket: boolean = false,
      secondaryMeta?: { projectLabel?: string | null; branchLabel?: string | null } | null,
      renderContext: 'project' | 'recent' = 'project',
      renderExtras?: SessionNodeRenderExtras,
    ): React.ReactNode => (
      <SessionNodeItem
        node={node}
@@ -1240,16 +1312,16 @@ export const SessionSidebar: React.FC<SessionSidebarProps> = ({
        setEditingId={setEditingId}
        editTitle={editTitle}
        setEditTitle={setEditTitle}
-        handleSaveEdit={handleSaveEdit}
+        handleSaveEdit={stableHandleSaveEdit}
-        handleCancelEdit={handleCancelEdit}
+        handleCancelEdit={stableHandleCancelEdit}
        toggleParent={toggleParent}
-        handleSessionSelect={handleSessionSelect}
+        handleSessionSelect={stableHandleSessionSelect}
-        handleSessionDoubleClick={handleSessionDoubleClick}
+        handleSessionDoubleClick={stableHandleSessionDoubleClick}
        togglePinnedSession={togglePinnedSession}
-        handleShareSession={handleShareSession}
+        handleShareSession={stableHandleShareSession}
        copiedSessionId={copiedSessionId}
-        handleCopyShareUrl={handleCopyShareUrl}
+        handleCopyShareUrl={stableHandleCopyShareUrl}
-        handleUnshareSession={handleUnshareSession}
+        handleUnshareSession={stableHandleUnshareSession}
        openSidebarMenuKey={openSidebarMenuKey}
        setOpenSidebarMenuKey={setOpenSidebarMenuKey}
        renamingFolderId={renamingFolderId}
@@ -1257,50 +1329,22 @@ export const SessionSidebar: React.FC<SessionSidebarProps> = ({
        getSessionFolderId={getSessionFolderId}
        removeSessionFromFolder={removeSessionFromFolder}
        addSessionToFolder={addSessionToFolder}
-        createFolderAndStartRename={createFolderAndStartRename}
+        createFolderAndStartRename={stableCreateFolderAndStartRename}
        openContextPanelTab={openContextPanelTab}
-        handleDeleteSession={handleDeleteSession}
+        handleDeleteSession={stableHandleDeleteSession}
        mobileVariant={mobileVariant}
        alwaysShowActions={alwaysShowSidebarActions}
        renderSessionNode={renderSessionNode}
        secondaryMeta={secondaryMeta}
        renderContext={renderContext}
        subtreeContainsActive={renderExtras?.subtreeContainsActive ?? EMPTY_SUBTREE_SET}
        subtreeContainsEditing={renderExtras?.subtreeContainsEditing ?? EMPTY_SUBTREE_SET}
        menuOpenSessionId={renderExtras?.menuOpenSessionId ?? null}
        nodeStructureKey={renderExtras?.nodeStructureKey ?? ''}
        childRenderExtrasFor={renderExtras?.childRenderExtrasFor}
        liveSessionById={liveSessionById}
      />
    ),
    [
      currentSessionId,
      pinnedSessionIds,
      expandedParents,
      hasSessionSearchQuery,
      normalizedSessionSearchQuery,
      notifyOnSubtasks,
      editingId,
      setEditingId,
      editTitle,
      setEditTitle,
      handleSaveEdit,
      handleCancelEdit,
      toggleParent,
      handleSessionSelect,
      handleSessionDoubleClick,
      togglePinnedSession,
      handleShareSession,
      copiedSessionId,
      handleCopyShareUrl,
      handleUnshareSession,
      openSidebarMenuKey,
      setOpenSidebarMenuKey,
      renamingFolderId,
      getFoldersForScope,
      getSessionFolderId,
      removeSessionFromFolder,
      addSessionToFolder,
      createFolderAndStartRename,
      openContextPanelTab,
      handleDeleteSession,
      mobileVariant,
      alwaysShowSidebarActions,
    ],
  );
  const toggleCollapsedGroup = React.useCallback((key: string) => {
@@ -1335,7 +1379,15 @@ export const SessionSidebar: React.FC<SessionSidebarProps> = ({
  }, [prVisualSummaryMap]);
  const renderGroupSessions = React.useCallback(
-    (group: SessionGroup, groupKey: string, projectId?: string | null, hideGroupLabel?: boolean, dragHandleProps?: SortableDragHandleProps | null, compactBodyPadding?: boolean) => (
+    (
      group: SessionGroup,
      groupKey: string,
      projectId?: string | null,
      hideGroupLabel?: boolean,
      dragHandleProps?: SortableDragHandleProps | null,
      compactBodyPadding?: boolean,
      scrollContainerRef?: React.RefObject<HTMLElement | null>,
    ) => (
      <SessionGroupSection
        group={group}
        groupKey={groupKey}
@@ -1355,7 +1407,6 @@ export const SessionSidebar: React.FC<SessionSidebarProps> = ({
        showDeletionDialog={showDeletionDialog}
        setDeleteFolderConfirm={setDeleteFolderConfirm}
        renderSessionNode={renderSessionNode}
        currentSessionDirectory={currentSessionDirectory}
        projectRepoStatus={projectRepoStatus}
        lastRepoStatus={lastRepoStatusRef.current}
        showMoreGroupSessions={showMoreGroupSessions}
@@ -1368,16 +1419,23 @@ export const SessionSidebar: React.FC<SessionSidebarProps> = ({
        setSessionSwitcherOpen={setSessionSwitcherOpen}
        openNewSessionDraft={openNewSessionDraftFromTree}
        addSessionToFolder={addSessionToFolder}
-        createFolderAndStartRename={createFolderAndStartRename}
+        createFolderAndStartRename={stableCreateFolderAndStartRename}
        renamingFolderId={renamingFolderId}
        renameFolderDraft={renameFolderDraft}
        setRenameFolderDraft={setRenameFolderDraft}
        setRenamingFolderId={setRenamingFolderId}
        pinnedSessionIds={pinnedSessionIds}
        expandedParents={expandedParents}
        sessionOrderIndex={sessionOrderIndex}
        currentSessionId={currentSessionId}
        editingId={editingId}
        editTitle={editTitle}
        openSidebarMenuKey={openSidebarMenuKey}
        liveSessionById={liveSessionById}
        prVisualStateByDirectoryBranch={prVisualStateByDirectoryBranch}
        onToggleCollapsedGroup={toggleCollapsedGroup}
        dragHandleProps={dragHandleProps}
        scrollContainerRef={scrollContainerRef}
      />
    ),
    [
@@ -1393,7 +1451,6 @@ export const SessionSidebar: React.FC<SessionSidebarProps> = ({
      deleteFolder,
      showDeletionDialog,
      renderSessionNode,
      currentSessionDirectory,
      projectRepoStatus,
      showMoreGroupSessions,
      resetGroupSessionLimit,
@@ -1405,11 +1462,17 @@ export const SessionSidebar: React.FC<SessionSidebarProps> = ({
      setSessionSwitcherOpen,
      openNewSessionDraftFromTree,
      addSessionToFolder,
-      createFolderAndStartRename,
+      stableCreateFolderAndStartRename,
      renamingFolderId,
      renameFolderDraft,
      pinnedSessionIds,
      expandedParents,
      sessionOrderIndex,
      currentSessionId,
      editingId,
      editTitle,
      openSidebarMenuKey,
      liveSessionById,
      prVisualStateByDirectoryBranch,
      toggleCollapsedGroup,
    ],
@@ -1419,174 +1482,40 @@ export const SessionSidebar: React.FC<SessionSidebarProps> = ({
    <SidebarActivitySections
      sections={activitySections}
      renderSessionNode={renderSessionNode}
      currentSessionId={currentSessionId}
      editingId={editingId}
      openSidebarMenuKey={openSidebarMenuKey}
      variant="section"
    />
  ) : null;
  const isInlineEditing = Boolean(renamingFolderId || editingId || editingProjectDialogId);
-  const selectionModeEnabled = useSessionMultiSelectStore((state) => state.enabled);
+  const {
-  const selectedIds = useSessionMultiSelectStore((state) => state.selectedIds);
+    selectionModeEnabled,
-  const selectionScopeKey = useSessionMultiSelectStore((state) => state.scopeKey);
+    hasSelection,
-  const multiSelectStoreApi = useSessionMultiSelectStore;
+    selectedIdsSize,
-
+    bulkScopeIsArchived,
-  const handleToggleSelectionMode = React.useCallback(() => {
+    derivedSelectionScope,
-    useSessionMultiSelectStore.getState().toggleMode();
+    bulkScopeFolders,
-  }, []);
+    bulkCanRemoveFromFolder,
-  const handleExitSelectionMode = React.useCallback(() => {
+    handleToggleSelectionMode,
-    useSessionMultiSelectStore.getState().disable();
+    handleExitSelectionMode,
-  }, []);
+    handleBulkMoveToFolder,
-
+    handleBulkCreateFolderAndMove,
-  const bulkScopeIsArchived = React.useMemo(() => {
+    handleBulkRemoveFromFolder,
-    if (selectedIds.size === 0) return false;
+    handleBulkDelete,
-    if (typeof document === 'undefined') return false;
+    confirmBulkDelete,
-    let sawActive = false;
+  } = useSidebarBulkActions({
-    let sawArchived = false;
+    isInlineEditing,
-    for (const id of selectedIds) {
+    showDeletionDialog,
-      const rows = document.querySelectorAll<HTMLElement>(`[data-session-row="${CSS.escape(id)}"]`);
+    foldersMap,
-      for (const row of rows) {
+    addSessionsToFolder,
-        if (row.getAttribute('data-session-archived') === '1') sawArchived = true;
+    removeSessionsFromFolders,
-        else sawActive = true;
+    createFolderAndStartRename,
-      }
+    archiveSessions,
-    }
+    deleteSessions,
-    return sawArchived && !sawActive;
+    setBulkDeleteConfirm,
-  }, [selectedIds]);
+  });
  const derivedSelectionScope = React.useMemo(() => {
    if (selectionScopeKey) return selectionScopeKey;
    if (selectedIds.size === 0) return null;
    if (typeof document === 'undefined') return null;
    for (const id of selectedIds) {
      const row = document.querySelector<HTMLElement>(`[data-session-row="${CSS.escape(id)}"]`);
      const scope = row?.getAttribute('data-session-scope');
      if (scope && scope.length > 0) return scope;
    }
    return null;
  }, [selectedIds, selectionScopeKey]);
  const bulkScopeFolders = React.useMemo(() => {
    if (!derivedSelectionScope) return [];
    return foldersMap[derivedSelectionScope] ?? [];
  }, [foldersMap, derivedSelectionScope]);
  const bulkCanRemoveFromFolder = React.useMemo(() => {
    if (!derivedSelectionScope || selectedIds.size === 0) return false;
    const scopeFolders = foldersMap[derivedSelectionScope] ?? [];
    for (const folder of scopeFolders) {
      for (const id of folder.sessionIds) {
        if (selectedIds.has(id)) return true;
      }
    }
    return false;
  }, [foldersMap, derivedSelectionScope, selectedIds]);
  const handleBulkMoveToFolder = React.useCallback((folderId: string) => {
    if (!derivedSelectionScope || selectedIds.size === 0) return;
    addSessionsToFolder(derivedSelectionScope, folderId, Array.from(selectedIds));
  }, [addSessionsToFolder, selectedIds, derivedSelectionScope]);
  const handleBulkCreateFolderAndMove = React.useCallback(() => {
    if (!derivedSelectionScope || selectedIds.size === 0) return;
    const newFolder = createFolderAndStartRename(derivedSelectionScope);
    if (!newFolder) return;
    addSessionsToFolder(derivedSelectionScope, newFolder.id, Array.from(selectedIds));
  }, [addSessionsToFolder, createFolderAndStartRename, selectedIds, derivedSelectionScope]);
  const handleBulkRemoveFromFolder = React.useCallback(() => {
    if (!derivedSelectionScope || selectedIds.size === 0) return;
    removeSessionsFromFolders(derivedSelectionScope, Array.from(selectedIds));
  }, [removeSessionsFromFolders, selectedIds, derivedSelectionScope]);
  const executeBulkDelete = React.useCallback(async () => {
    const ids = Array.from(selectedIds);
    if (ids.length === 0) return;
    if (bulkScopeIsArchived) {
      const { deletedIds, failedIds } = await deleteSessions(ids);
      if (deletedIds.length > 0) {
        toast.success(deletedIds.length === 1
          ? t('sessions.sidebar.bulkActions.deletedSingle', { count: deletedIds.length })
          : t('sessions.sidebar.bulkActions.deletedPlural', { count: deletedIds.length }));
      }
      if (failedIds.length > 0) {
        toast.error(failedIds.length === 1
          ? t('sessions.sidebar.bulkActions.failedDeleteSingle', { count: failedIds.length })
          : t('sessions.sidebar.bulkActions.failedDeletePlural', { count: failedIds.length }));
      }
    } else {
      const { archivedIds, failedIds } = await archiveSessions(ids);
      if (archivedIds.length > 0) {
        toast.success(archivedIds.length === 1
          ? t('sessions.sidebar.bulkActions.archivedSingle', { count: archivedIds.length })
          : t('sessions.sidebar.bulkActions.archivedPlural', { count: archivedIds.length }));
      }
      if (failedIds.length > 0) {
        toast.error(failedIds.length === 1
          ? t('sessions.sidebar.bulkActions.failedArchiveSingle', { count: failedIds.length })
          : t('sessions.sidebar.bulkActions.failedArchivePlural', { count: failedIds.length }));
      }
    }
    useSessionMultiSelectStore.getState().clear();
  }, [archiveSessions, bulkScopeIsArchived, deleteSessions, selectedIds, t]);
  const handleBulkDelete = React.useCallback(() => {
    const count = selectedIds.size;
    if (count === 0) return;
    if (!showDeletionDialog) {
      void executeBulkDelete();
      return;
    }
    setBulkDeleteConfirm({ sessionCount: count, archivedBucket: bulkScopeIsArchived });
  }, [bulkScopeIsArchived, executeBulkDelete, selectedIds, showDeletionDialog]);
  const confirmBulkDelete = React.useCallback(async () => {
    setBulkDeleteConfirm(null);
    await executeBulkDelete();
  }, [executeBulkDelete]);
  React.useEffect(() => {
    if (!selectionModeEnabled) return;
    const isMac = typeof navigator !== 'undefined' && /Macintosh|Mac OS X/.test(navigator.userAgent || '');
    const listener = (event: KeyboardEvent) => {
      if (isInlineEditing) return;
      const target = event.target as HTMLElement | null;
      if (target && (target.tagName === 'INPUT' || target.tagName === 'TEXTAREA' || target.isContentEditable)) {
        return;
      }
      const modifier = isMac ? event.metaKey : event.ctrlKey;
      if (event.key === 'Escape') {
        event.preventDefault();
        useSessionMultiSelectStore.getState().disable();
        return;
      }
      if (modifier && event.key === 'Backspace') {
        event.preventDefault();
        handleBulkDelete();
        return;
      }
      if (modifier && (event.key === 'a' || event.key === 'A')) {
        const rows = typeof document !== 'undefined'
          ? Array.from(document.querySelectorAll<HTMLElement>('[data-session-row]'))
          : [];
        if (rows.length === 0) return;
        event.preventDefault();
        const currentScope = multiSelectStoreApi.getState().scopeKey;
        const targetScope = currentScope
          ?? rows[0]?.getAttribute('data-session-scope')
          ?? null;
        const scopeFilter = (el: HTMLElement): boolean => {
          if (!targetScope) return true;
          return el.getAttribute('data-session-scope') === targetScope;
        };
        const ids = rows
          .filter(scopeFilter)
          .map((el) => el.getAttribute('data-session-row'))
          .filter((id): id is string => typeof id === 'string' && id.length > 0);
        if (ids.length === 0) return;
        multiSelectStoreApi.getState().replaceAll(ids, targetScope || null);
      }
    };
    window.addEventListener('keydown', listener);
    return () => window.removeEventListener('keydown', listener);
  }, [handleBulkDelete, isInlineEditing, multiSelectStoreApi, selectionModeEnabled]);
  const handleOpenMultiRunFromHeader = React.useCallback(() => {
    setActiveMainTab('chat');
    if (mobileVariant) {
@@ -1670,9 +1599,9 @@ export const SessionSidebar: React.FC<SessionSidebarProps> = ({
        isInlineEditing={isInlineEditing}
      />
-      {selectionModeEnabled && selectedIds.size > 0 ? (
+      {selectionModeEnabled && hasSelection ? (
        <BulkActionBar
-          selectedCount={selectedIds.size}
+          selectedCount={selectedIdsSize}
          scopeKey={derivedSelectionScope}
          scopeFolders={bulkScopeFolders}
          archivedBucket={bulkScopeIsArchived}
@@ -5,6 +5,11 @@ import type { Session } from '@opencode-ai/sdk/v2';
 // Archived buckets routinely grow into the hundreds/thousands; virtualize
 // when we cross this row count so the DOM stays bounded.
 const ARCHIVED_VIRTUALIZE_THRESHOLD = 50;
 // Active/worktree groups can also grow large (a single worktree with 80+
 // sessions), and unlike the archive they're interactive from the start.
 // Virtualize eagerly for non-archived groups to keep the rendered row
 // count bounded. With overscan ~8 the visible behavior is identical.
 const ACTIVE_VIRTUALIZE_THRESHOLD = 30;
 // Compact rows in the archived bucket without nested subagents render
 // around 24-32px; virtua measures mounted rows and uses this as the initial hint.
 const ARCHIVED_ROW_ESTIMATE_PX = 28;
@@ -18,6 +23,13 @@ import { DroppableFolderWrapper, SessionFolderDndScope } from './sessionFolderDn
 import type { SortableDragHandleProps } from './sortableItems';
 import type { GroupSearchData, SessionGroup, SessionNode } from './types';
 import { compareSessionsByPinnedAndTime, isBranchDifferentFromLabel, normalizePath, renderHighlightedText } from './utils';
 import {
  collectSubtreeContainingId,
  computeNodeStructureKey,
  nodeContainsSessionId,
  resolveMenuOpenSessionId,
 } from './sessionNodeItemUtils';
 import type { SessionNodeRenderExtras } from './sessionNodeItemUtils';
 import type { SessionFolder } from '@/stores/useSessionFoldersStore';
 import { useSessionFoldersStore } from '@/stores/useSessionFoldersStore';
 import { useSessionDisplayStore } from '@/stores/useSessionDisplayStore';
@@ -50,8 +62,16 @@ type Props = {
  deleteFolder: (scopeKey: string, folderId: string) => void;
  showDeletionDialog: boolean;
  setDeleteFolderConfirm: React.Dispatch<React.SetStateAction<DeleteFolderConfirm>>;
-  renderSessionNode: (node: SessionNode, depth?: number, groupDirectory?: string | null, projectId?: string | null, archivedBucket?: boolean, secondaryMeta?: { projectLabel?: string | null; branchLabel?: string | null } | null) => React.ReactNode;
+  renderSessionNode: (
-  currentSessionDirectory: string | null;
+    node: SessionNode,
    depth?: number,
    groupDirectory?: string | null,
    projectId?: string | null,
    archivedBucket?: boolean,
    secondaryMeta?: { projectLabel?: string | null; branchLabel?: string | null } | null,
    renderContext?: 'project' | 'recent',
    renderExtras?: SessionNodeRenderExtras,
  ) => React.ReactNode;
  projectRepoStatus: Map<string, boolean | null>;
  lastRepoStatus: boolean;
  showMoreGroupSessions: (groupKey: string, currentVisibleCount: number) => void;
@@ -70,7 +90,13 @@ type Props = {
  setRenameFolderDraft: React.Dispatch<React.SetStateAction<string>>;
  setRenamingFolderId: React.Dispatch<React.SetStateAction<string | null>>;
  pinnedSessionIds: Set<string>;
  expandedParents: Set<string>;
  sessionOrderIndex: Map<string, number>;
  currentSessionId: string | null;
  editingId: string | null;
  editTitle: string;
  openSidebarMenuKey: string | null;
  liveSessionById: Map<string, Session>;
  prVisualStateByDirectoryBranch: Map<string, {
    visualState: 'draft' | 'open' | 'blocked' | 'merged' | 'closed';
    number: number;
@@ -97,9 +123,196 @@ type Props = {
  onToggleCollapsedGroup: (groupKey: string) => void;
  dragHandleProps?: SortableDragHandleProps | null;
  compactBodyPadding?: boolean;
  /**
   * Optional scroll container ref threaded from the outer ScrollableOverlay.
   * When provided, the virtualization effect can resolve the scrolling
   * ancestor synchronously and skip the getComputedStyle walk on every
   * render of an expanded archived bucket.
   */
  scrollContainerRef?: React.RefObject<HTMLElement | null>;
 };
-export function SessionGroupSection(props: Props): React.ReactNode {
+const groupContainsSessionId = (group: SessionGroup, sessionId: string | null): boolean => {
  if (!sessionId) return false;
  return group.sessions.some((node) => nodeContainsSessionId(node, sessionId));
 };
 const groupHasPinnedMembershipChange = (
  group: SessionGroup,
  prevPinnedSessionIds: Set<string>,
  nextPinnedSessionIds: Set<string>,
 ): boolean => {
  const visit = (node: SessionNode): boolean => {
    const sessionId = node.session.id;
    if (prevPinnedSessionIds.has(sessionId) !== nextPinnedSessionIds.has(sessionId)) return true;
    return node.children.some(visit);
  };
  return group.sessions.some(visit);
 };
 const groupHasSessionOrderChange = (
  group: SessionGroup,
  prevSessionOrderIndex: Map<string, number>,
  nextSessionOrderIndex: Map<string, number>,
 ): boolean => {
  const visit = (node: SessionNode): boolean => {
    const sessionId = node.session.id;
    if (prevSessionOrderIndex.get(sessionId) !== nextSessionOrderIndex.get(sessionId)) return true;
    return node.children.some(visit);
  };
  return group.sessions.some(visit);
 };
 const groupHasExpansionMembershipChange = (
  group: SessionGroup,
  prevExpandedParents: Set<string>,
  nextExpandedParents: Set<string>,
 ): boolean => {
  const bucketTag = group.isArchivedBucket ? 'archived' : 'active';
  const visit = (node: SessionNode): boolean => {
    const key = `project:${bucketTag}:${node.session.id}`;
    if (prevExpandedParents.has(key) !== nextExpandedParents.has(key)) return true;
    return node.children.some(visit);
  };
  return group.sessions.some(visit);
 };
 const groupHasResolvedSessionChange = (
  group: SessionGroup,
  prevLiveSessionById: Map<string, Session>,
  nextLiveSessionById: Map<string, Session>,
 ): boolean => {
  const visit = (node: SessionNode): boolean => {
    const sessionId = node.session.id;
    if ((prevLiveSessionById.get(sessionId) ?? node.session) !== (nextLiveSessionById.get(sessionId) ?? node.session)) {
      return true;
    }
    return node.children.some(visit);
  };
  return group.sessions.some(visit);
 };
 const getProjectRepoStatusValue = (props: Props): boolean | null | undefined => {
  if (!props.projectId) return undefined;
  return props.projectRepoStatus.has(props.projectId)
    ? props.projectRepoStatus.get(props.projectId)
    : undefined;
 };
 const areGroupPropsEqual = (prev: Props, next: Props): boolean => {
  // Bail on Object.is for the props that drive the most work: the group
  // itself, its key, and the group-level chrome. These change rarely and
  // any change should force a re-render of this group.
  if (prev.group !== next.group) return false;
  if (prev.groupKey !== next.groupKey) return false;
  if (prev.projectId !== next.projectId) return false;
  if (prev.hideGroupLabel !== next.hideGroupLabel) return false;
  if (prev.compactBodyPadding !== next.compactBodyPadding) return false;
  if (prev.groupSearchDataByGroup !== next.groupSearchDataByGroup) return false;
  if (prev.visibleSessionCount !== next.visibleSessionCount) return false;
  if (prev.collapsedGroups !== next.collapsedGroups
    && prev.collapsedGroups.has(prev.groupKey) !== next.collapsedGroups.has(next.groupKey)) {
    return false;
  }
  if (prev.projectRepoStatus !== next.projectRepoStatus
    && getProjectRepoStatusValue(prev) !== getProjectRepoStatusValue(next)) {
    return false;
  }
  if (prev.pinnedSessionIds !== next.pinnedSessionIds
    && groupHasPinnedMembershipChange(next.group, prev.pinnedSessionIds, next.pinnedSessionIds)) {
    return false;
  }
  if (prev.expandedParents !== next.expandedParents
    && groupHasExpansionMembershipChange(next.group, prev.expandedParents, next.expandedParents)) {
    return false;
  }
  if (prev.sessionOrderIndex !== next.sessionOrderIndex
    && groupHasSessionOrderChange(next.group, prev.sessionOrderIndex, next.sessionOrderIndex)) {
    return false;
  }
  if (prev.currentSessionId !== next.currentSessionId
    && (groupContainsSessionId(prev.group, prev.currentSessionId) || groupContainsSessionId(next.group, next.currentSessionId))) {
    return false;
  }
  if (prev.editingId !== next.editingId
    && (groupContainsSessionId(prev.group, prev.editingId) || groupContainsSessionId(next.group, next.editingId))) {
    return false;
  }
  if (prev.editTitle !== next.editTitle
    && (groupContainsSessionId(prev.group, prev.editingId) || groupContainsSessionId(next.group, next.editingId))) {
    return false;
  }
  if (prev.openSidebarMenuKey !== next.openSidebarMenuKey) {
    const prevMenuSessionId = resolveMenuOpenSessionId(prev.group.sessions, prev.openSidebarMenuKey, 'project', Boolean(prev.group.isArchivedBucket));
    const nextMenuSessionId = resolveMenuOpenSessionId(next.group.sessions, next.openSidebarMenuKey, 'project', Boolean(next.group.isArchivedBucket));
    if (prevMenuSessionId || nextMenuSessionId) return false;
  }
  if (prev.liveSessionById !== next.liveSessionById
    && groupHasResolvedSessionChange(next.group, prev.liveSessionById, next.liveSessionById)) {
    return false;
  }
  // Per-row / per-state props. The PR-visual-state map flips frequently
  // during bootstrap but a single group's value is usually stable, so we
  // compare only the value this group actually consumes instead of the
  // whole map reference.
  if (prev.prVisualStateByDirectoryBranch !== next.prVisualStateByDirectoryBranch) {
    const prevVal = prev.group?.directory && prev.group?.branch
      ? prev.prVisualStateByDirectoryBranch.get(`${prev.group.directory}::${prev.group.branch.trim()}`)
      : undefined;
    const nextVal = next.group?.directory && next.group?.branch
      ? next.prVisualStateByDirectoryBranch.get(`${next.group.directory}::${next.group.branch.trim()}`)
      : undefined;
    if (!Object.is(prevVal, nextVal)) return false;
  }
  // Other props are typically stable references from the parent. Default
  // to reference equality (the cheap path) and only re-render when the
  // parent actually swapped something.
  return (
    prev.hasSessionSearchQuery === next.hasSessionSearchQuery
    && prev.normalizedSessionSearchQuery === next.normalizedSessionSearchQuery
    && prev.hideDirectoryControls === next.hideDirectoryControls
    && prev.collapsedFolderIds === next.collapsedFolderIds
    && prev.toggleFolderCollapse === next.toggleFolderCollapse
    && prev.renameFolder === next.renameFolder
    && prev.deleteFolder === next.deleteFolder
    && prev.showDeletionDialog === next.showDeletionDialog
    && prev.setDeleteFolderConfirm === next.setDeleteFolderConfirm
    && prev.renderSessionNode === next.renderSessionNode
    && prev.lastRepoStatus === next.lastRepoStatus
    && prev.showMoreGroupSessions === next.showMoreGroupSessions
    && prev.resetGroupSessionLimit === next.resetGroupSessionLimit
    && prev.mobileVariant === next.mobileVariant
    && prev.alwaysShowActions === next.alwaysShowActions
    && prev.activeProjectId === next.activeProjectId
    && prev.setActiveProjectIdOnly === next.setActiveProjectIdOnly
    && prev.setActiveMainTab === next.setActiveMainTab
    && prev.setSessionSwitcherOpen === next.setSessionSwitcherOpen
    && prev.openNewSessionDraft === next.openNewSessionDraft
    && prev.addSessionToFolder === next.addSessionToFolder
    && prev.createFolderAndStartRename === next.createFolderAndStartRename
    && prev.renamingFolderId === next.renamingFolderId
    && prev.renameFolderDraft === next.renameFolderDraft
    && prev.setRenameFolderDraft === next.setRenameFolderDraft
    && prev.setRenamingFolderId === next.setRenamingFolderId
    && prev.onToggleCollapsedGroup === next.onToggleCollapsedGroup
    && prev.dragHandleProps === next.dragHandleProps
    && prev.scrollContainerRef === next.scrollContainerRef
  );
 };
 function SessionGroupSectionBase(props: Props): React.ReactNode {
  const { t } = useI18n();
  const {
    group,
@@ -138,10 +351,14 @@ export function SessionGroupSection(props: Props): React.ReactNode {
    setRenamingFolderId,
    pinnedSessionIds,
    sessionOrderIndex,
    currentSessionId,
    editingId,
    openSidebarMenuKey,
    prVisualStateByDirectoryBranch,
    onToggleCollapsedGroup,
    dragHandleProps,
    compactBodyPadding = false,
    scrollContainerRef,
  } = props;
  const compareSessionNodes = React.useCallback((a: SessionNode, b: SessionNode) => {
@@ -254,6 +471,79 @@ export function SessionGroupSection(props: Props): React.ReactNode {
  const ungroupedSessions = React.useMemo(() => sourceGroupNodes.filter((node) => !sessionIdsInFolders.has(node.session.id)), [sourceGroupNodes, sessionIdsInFolders]);
  const rootFolders = React.useMemo(() => allFoldersForGroup.filter(({ folder }) => !folder.parentId), [allFoldersForGroup]);
  // Precompute per-row "subtree contains active session" and "subtree contains
  // editing session" lookups once per render. The previous design walked the
  // node tree inside SessionNodeItem.areEqual for every row, which is O(M^2)
  // across the whole sidebar. These sets let areEqual answer with a single
  // Set.has lookup, so the cost is O(M) once per SessionGroupSection render.
  const renderContextForGroup = 'project' as const;
  const subtreeContainsActive = React.useMemo(() => {
    const set = new Set<string>();
    collectSubtreeContainingId(sourceGroupNodes, currentSessionId, set);
    allFoldersForGroup.forEach(({ nodes }) => {
      collectSubtreeContainingId(nodes, currentSessionId, set);
    });
    return set;
  }, [sourceGroupNodes, allFoldersForGroup, currentSessionId]);
  const subtreeContainsEditing = React.useMemo(() => {
    const set = new Set<string>();
    collectSubtreeContainingId(sourceGroupNodes, editingId, set);
    allFoldersForGroup.forEach(({ nodes }) => {
      collectSubtreeContainingId(nodes, editingId, set);
    });
    return set;
  }, [sourceGroupNodes, allFoldersForGroup, editingId]);
  const menuOpenSessionId = React.useMemo(() => {
    if (!openSidebarMenuKey) return null;
    const fromSource = resolveMenuOpenSessionId(sourceGroupNodes, openSidebarMenuKey, renderContextForGroup, Boolean(group.isArchivedBucket));
    if (fromSource) return fromSource;
    for (const { nodes } of allFoldersForGroup) {
      const id = resolveMenuOpenSessionId(nodes, openSidebarMenuKey, renderContextForGroup, Boolean(group.isArchivedBucket));
      if (id) return id;
    }
    return null;
  }, [openSidebarMenuKey, sourceGroupNodes, allFoldersForGroup, group.isArchivedBucket]);
  const buildNodeStructureKeyByNode = React.useCallback((nodes: SessionNode[]): WeakMap<SessionNode, string> => {
    const map = new WeakMap<SessionNode, string>();
    const visit = (node: SessionNode): void => {
      map.set(node, computeNodeStructureKey(node));
      for (const child of node.children) {
        visit(child);
      }
    };
    nodes.forEach(visit);
    return map;
  }, []);
  const nodeStructureKeyBySourceNode = React.useMemo(
    () => buildNodeStructureKeyByNode(sourceGroupNodes),
    [buildNodeStructureKeyByNode, sourceGroupNodes],
  );
  const nodeStructureKeyByFolderNode = React.useMemo(
    () => {
      const map = new WeakMap<SessionNode, string>();
      allFoldersForGroup.forEach(({ nodes }) => {
        nodes.forEach((node) => map.set(node, computeNodeStructureKey(node)));
      });
      return map;
    },
    [allFoldersForGroup],
  );
  const resolveNodeStructureKey = React.useCallback((node: SessionNode): string => {
    return nodeStructureKeyBySourceNode.get(node) ?? nodeStructureKeyByFolderNode.get(node) ?? '';
  }, [nodeStructureKeyBySourceNode, nodeStructureKeyByFolderNode]);
  const childRenderExtrasFor = React.useCallback((child: SessionNode) => ({
    subtreeContainsActive,
    subtreeContainsEditing,
    menuOpenSessionId,
    nodeStructureKey: resolveNodeStructureKey(child),
  }), [subtreeContainsActive, subtreeContainsEditing, menuOpenSessionId, resolveNodeStructureKey]);
  const totalSessions = ungroupedSessions.length;
  const visibleSessions = group.isArchivedBucket
    ? ungroupedSessions
@@ -263,15 +553,21 @@ export function SessionGroupSection(props: Props): React.ReactNode {
  const remainingCount = totalSessions - visibleSessions.length;
  const canShowLess = !group.isArchivedBucket && !hasSessionSearchQuery && totalSessions > maxVisible && remainingCount === 0;
-  // Virtualize the archived bucket once it grows past a threshold. The
+  // Virtualize large groups. Archived buckets grow into the hundreds or
-  // archived list is the only group that can routinely hit hundreds or
+  // thousands of rows; active/worktree groups can also hit 80+ sessions
-  // thousands of rows (projects accumulate archived sessions over time);
+  // when a single worktree accumulates over time. Both paths share the
-  // every other group renders eagerly because they're small. All hooks
+  // same virtua Virtualizer; the threshold just controls when we mount
-  // below MUST stay above the search-empty early-return so they fire in
+  // it. The visible behavior is identical because virtua uses overscan
-  // the same order every render — rules-of-hooks.
+  // (8) for the buffer zone. All hooks below MUST stay above the
  // search-empty early-return so they fire in the same order every
  // render — rules-of-hooks.
  const shouldVirtualizeArchived = group.isArchivedBucket === true
    && !hasSessionSearchQuery
    && visibleSessions.length >= ARCHIVED_VIRTUALIZE_THRESHOLD;
  const shouldVirtualizeActive = group.isArchivedBucket !== true
    && !hasSessionSearchQuery
    && visibleSessions.length >= ACTIVE_VIRTUALIZE_THRESHOLD;
  const shouldVirtualize = shouldVirtualizeArchived || shouldVirtualizeActive;
  const archivedVirtualContainerRef = React.useRef<HTMLDivElement | null>(null);
  const archivedScrollRef = React.useRef<HTMLElement | null>(null);
@@ -284,22 +580,31 @@ export function SessionGroupSection(props: Props): React.ReactNode {
  // element and renders rows in the wrong subset / position.
  const [archivedScrollMargin, setArchivedScrollMargin] = React.useState(0);
-  // Find the nearest scrolling ancestor by walking up the DOM. The sidebar
+  // Resolve the scrolling ancestor. When the parent has threaded a
-  // routes its scroll through `ScrollableOverlay` higher up the tree;
+  // `scrollContainerRef` (Layer 1.4), use it directly to skip the
-  // threading a ref through every intermediate component would be invasive
+  // `getComputedStyle` walk on every render of an expanded archived
-  // for this single use case.
+  // bucket — the walk is one of the more expensive operations in the
-  // Resolve the scrolling ancestor and measure the virtual container's offset
+  // hot path because it forces a style recalc on every parent up the
-  // from its content origin, both on every render. The container ref is null
+  // tree. Fall back to the legacy walk only when the ref is missing.
-  // while the archived bucket is collapsed (the body isn't mounted), so a
+  //
  // We also still re-run when the archive flips between expanded/collapsed,
  // and on a ResizeObserver-driven layout change of the container, so a
  // dep-gated effect that only fires when shouldVirtualizeArchived flips
-  // would miss the eventual mount and leave the scroll element null forever.
+  // would miss the eventual mount and leave the scroll element null.
-  // Running on every render lets us pick up the container as soon as
+  const [, setLayoutVersion] = React.useState(0);
-  // expanding the bucket mounts it; the cached scroll element is reused as
+  React.useEffect(() => {
-  // long as it still contains the container. Both state setters compare
+    if (!shouldVirtualize) return;
-  // before writing, so a stable layout produces no state churn.
+    const container = archivedVirtualContainerRef.current;
    if (!container) return;
    if (typeof ResizeObserver === 'undefined') return;
    const ro = new ResizeObserver(() => setLayoutVersion((v) => v + 1));
    ro.observe(container);
    return () => ro.disconnect();
  }, [shouldVirtualize]);
  // eslint-disable-next-line react-hooks/exhaustive-deps
  React.useLayoutEffect(() => {
-    if (!shouldVirtualizeArchived) {
+    if (!shouldVirtualize) {
      if (archivedScrollEl !== null) setArchivedScrollEl(null);
      archivedScrollRef.current = null;
      if (archivedScrollMargin !== 0) setArchivedScrollMargin(0);
@@ -312,7 +617,15 @@ export function SessionGroupSection(props: Props): React.ReactNode {
      return;
    }
    let scrollEl: HTMLElement | null = archivedScrollEl;
-    if (!scrollEl || !scrollEl.contains(container)) {
+    const providedScrollEl = scrollContainerRef?.current ?? null;
    if (providedScrollEl && providedScrollEl.contains(container)) {
      scrollEl = providedScrollEl;
      if (scrollEl !== archivedScrollEl) {
        archivedScrollRef.current = scrollEl;
        setArchivedScrollEl(scrollEl);
        return;
      }
    } else if (!scrollEl || !scrollEl.contains(container)) {
      // Walk up to find the nearest scrolling ancestor. Only happens on
      // first mount or if the DOM tree restructured.
      let el: HTMLElement | null = container.parentElement;
@@ -327,8 +640,6 @@ export function SessionGroupSection(props: Props): React.ReactNode {
      if (scrollEl !== archivedScrollEl) {
        archivedScrollRef.current = scrollEl;
        setArchivedScrollEl(scrollEl);
        // setState triggers a re-render; bail out and let the next pass
        // measure the margin against the fresh element.
        return;
      }
    }
@@ -339,11 +650,9 @@ export function SessionGroupSection(props: Props): React.ReactNode {
    setArchivedScrollMargin((prev) => (Math.abs(prev - offset) < 1 ? prev : offset));
  });
-  if (hasSessionSearchQuery && !groupMatchesSearch && rootFolders.length === 0 && ungroupedSessions.length === 0) {
+  // Hooks below MUST stay above the search-empty early-return so they
-    return null;
+  // fire in the same order every render — rules-of-hooks.
-  }
+  const collectGroupSessions = React.useCallback((nodes: SessionNode[]): Session[] => {
  const collectGroupSessions = (nodes: SessionNode[]): Session[] => {
    const collected: Session[] = [];
    const visit = (list: SessionNode[]) => {
      list.forEach((node) => {
@@ -353,9 +662,52 @@ export function SessionGroupSection(props: Props): React.ReactNode {
    };
    visit(nodes);
    return collected;
-  };
+  }, []);
  // The "delete all in group" handler closes over the full list of
  // sessions in this group. Memoize so the recursive flatten only runs
  // when the underlying source group nodes change, not on every render.
  const allGroupSessions = React.useMemo(
    () => (group.isArchivedBucket ? collectGroupSessions(sourceGroupNodes) : []),
    [collectGroupSessions, sourceGroupNodes, group.isArchivedBucket],
  );
  // Precompute the per-folder "delete all sessions in folder" list once
  // per render. The previous design ran a recursive `collectFolderSessions`
  // walk inside each folder's render, which is O(F × (S + F)) per group
  // render. With F=50 folders and S=200 archived sessions this is
  // significant; the precompute makes it O(F + S) once.
  const folderSessionsForDeleteById = React.useMemo(() => {
    if (!group.isArchivedBucket) return new Map<string, Session[]>();
    const result = new Map<string, Session[]>();
    const childIdsByParentId = new Map<string, string[]>();
    for (const { folder } of allFoldersForGroup) {
      if (!folder.parentId) continue;
      const existing = childIdsByParentId.get(folder.parentId) ?? [];
      existing.push(folder.id);
      childIdsByParentId.set(folder.parentId, existing);
    }
    const visit = (targetFolderId: string, seen: Set<string>): Session[] => {
      if (seen.has(targetFolderId)) return [];
      seen.add(targetFolderId);
      const directEntry = allFoldersForGroup.find(({ folder: candidate }) => candidate.id === targetFolderId);
      const collected: Session[] = directEntry ? collectGroupSessions(directEntry.nodes) : [];
      const childIds = childIdsByParentId.get(targetFolderId) ?? [];
      for (const childId of childIds) {
        collected.push(...visit(childId, seen));
      }
      return collected;
    };
    for (const { folder } of allFoldersForGroup) {
      result.set(folder.id, visit(folder.id, new Set()));
    }
    return result;
  }, [allFoldersForGroup, collectGroupSessions, group.isArchivedBucket]);
  if (hasSessionSearchQuery && !groupMatchesSearch && rootFolders.length === 0 && ungroupedSessions.length === 0) {
    return null;
  }
  const allGroupSessions = collectGroupSessions(sourceGroupNodes);
  const isGitProject = projectId && projectRepoStatus.has(projectId)
    ? Boolean(projectRepoStatus.get(projectId))
    : lastRepoStatus;
@@ -437,15 +789,7 @@ export function SessionGroupSection(props: Props): React.ReactNode {
    const subFolderItems = directSubFolders.length > 0
      ? <>{directSubFolders.map(({ folder: sf, nodes: sn }) => renderOneFolderItem(sf, sn, depth + 1))}</>
      : undefined;
-    const collectFolderSessions = (targetFolderId: string): Session[] => {
+    const folderSessionsForDelete = folderSessionsForDeleteById.get(folder.id) ?? [];
      const directNodes = allFoldersForGroup.find(({ folder: candidate }) => candidate.id === targetFolderId)?.nodes ?? [];
      const childFolders = allFoldersForGroup.filter(({ folder: candidate }) => candidate.parentId === targetFolderId);
      return [
        ...collectGroupSessions(directNodes),
        ...childFolders.flatMap(({ folder: child }) => collectFolderSessions(child.id)),
      ];
    };
    const folderSessionsForDelete = group.isArchivedBucket ? collectFolderSessions(folder.id) : [];
    return (
      <DroppableFolderWrapper key={folder.id} folderId={folder.id}>
@@ -485,6 +829,15 @@ export function SessionGroupSection(props: Props): React.ReactNode {
              });
            }}
            renderSessionNode={renderSessionNode}
            getRenderExtras={resolveNodeStructureKey
              ? (node) => ({
                subtreeContainsActive,
                subtreeContainsEditing,
                menuOpenSessionId,
                nodeStructureKey: resolveNodeStructureKey(node),
                childRenderExtrasFor,
              })
              : undefined}
            groupDirectory={group.directory}
            projectId={projectId}
            mobileVariant={mobileVariant}
@@ -546,7 +899,7 @@ export function SessionGroupSection(props: Props): React.ReactNode {
      }}
    >
      {renderFolderItems()}
-      {shouldVirtualizeArchived ? (
+      {shouldVirtualize ? (
        <div ref={archivedVirtualContainerRef}>
          <Virtualizer
            data={visibleSessions}
@@ -555,11 +908,23 @@ export function SessionGroupSection(props: Props): React.ReactNode {
            scrollRef={archivedScrollRef}
            startMargin={archivedScrollMargin}
          >
-            {(node) => renderSessionNode(node, 0, group.directory, projectId, true) as React.ReactElement}
+            {(node) => renderSessionNode(node, 0, group.directory, projectId, group.isArchivedBucket === true, undefined, 'project', {
              subtreeContainsActive,
              subtreeContainsEditing,
              menuOpenSessionId,
              nodeStructureKey: resolveNodeStructureKey(node),
              childRenderExtrasFor,
            }) as React.ReactElement}
          </Virtualizer>
        </div>
      ) : (
-        visibleSessions.map((node) => renderSessionNode(node, 0, group.directory, projectId, group.isArchivedBucket === true))
+        visibleSessions.map((node) => renderSessionNode(node, 0, group.directory, projectId, group.isArchivedBucket === true, undefined, 'project', {
          subtreeContainsActive,
          subtreeContainsEditing,
          menuOpenSessionId,
          nodeStructureKey: resolveNodeStructureKey(node),
          childRenderExtrasFor,
        }))
      )}
      {totalSessions === 0 && allFoldersForGroup.length === 0 ? (
        <div className="py-1 text-left typography-micro text-muted-foreground">
@@ -846,3 +1211,5 @@ export function SessionGroupSection(props: Props): React.ReactNode {
    </div>
  );
 }
 export const SessionGroupSection = React.memo(SessionGroupSectionBase, areGroupPropsEqual);
@@ -21,10 +21,12 @@ import { Dialog, DialogContent, DialogDescription, DialogFooter, DialogHeader, D
 import { Icon } from "@/components/icon/Icon";
 import { buildExportFilename, downloadAsMarkdown, formatSessionAsMarkdown, getExportRevealLabelKey, revealExportedMarkdown, saveAsMarkdownDesktop } from '@/lib/exportSession';
 import type { ChildSessionExport } from '@/lib/exportSession';
-import { buildSessionMessageRecordsSnapshot, useDirectoryStore, useGlobalSessionStatus, useSession, useSessionPermissions } from '@/sync/sync-context';
+import { buildSessionMessageRecordsSnapshot, useDirectoryStore, useGlobalSessionStatus, useSessionPermissions } from '@/sync/sync-context';
 import { useSync } from '@/sync/use-sync';
 import { useViewportStore, viewportSessionKey } from '@/sync/viewport-store';
 import { DraggableSessionRow } from './sessionFolderDnd';
 import { nodeContainsSessionId } from './sessionNodeItemUtils';
 import type { SessionNodeChildRenderExtras, SessionNodeRenderExtras } from './sessionNodeItemUtils';
 import type { SessionNode } from './types';
 import { formatSessionCompactDateLabel, formatSessionDateLabel, normalizePath, renderHighlightedText } from './utils';
 import { useSessionDisplayStore } from '@/stores/useSessionDisplayStore';
@@ -61,7 +63,7 @@ type Props = {
  setEditingId: (id: string | null) => void;
  editTitle: string;
  setEditTitle: (value: string) => void;
-  handleSaveEdit: () => void;
+  handleSaveEdit: (titleOverride?: string) => void;
  handleCancelEdit: () => void;
  toggleParent: (expansionKey: string) => void;
  handleSessionSelect: (sessionId: string, sessionDirectory: string | null, projectId?: string | null) => void;
@@ -83,133 +85,58 @@ type Props = {
  handleDeleteSession: (session: Session, source?: { archivedBucket?: boolean; hardDelete?: boolean }) => void;
  mobileVariant: boolean;
  alwaysShowActions: boolean;
-  renderSessionNode: (node: SessionNode, depth?: number, groupDirectory?: string | null, projectId?: string | null, archivedBucket?: boolean, secondaryMeta?: SecondaryMeta | null, renderContext?: 'project' | 'recent') => React.ReactNode;
+  renderSessionNode: (
    node: SessionNode,
    depth?: number,
    groupDirectory?: string | null,
    projectId?: string | null,
    archivedBucket?: boolean,
    secondaryMeta?: SecondaryMeta | null,
    renderContext?: 'project' | 'recent',
    renderExtras?: SessionNodeRenderExtras,
  ) => React.ReactNode;
  secondaryMeta?: SecondaryMeta | null;
  renderContext?: 'project' | 'recent';
-};
+  /**
-
+   * Precomputed set of session IDs whose subtree contains the current
-const getNodeChildSignature = (node: SessionNode): string => {
+   * active session. Computed once per SessionGroupSection render (when
-  if (node.children.length === 0) {
+   * currentSessionId changes) instead of being recomputed in every row's
-    return '';
+   * React.memo comparator.
-  }
+   */
-
+  subtreeContainsActive: Set<string>;
-  return node.children
+  /**
-    .map((child) => `${child.session.id}:${child.children.length}`)
+   * Precomputed set of session IDs whose subtree contains the session
-    .join('|');
+   * currently being edited. Same rationale as subtreeContainsActive.
-};
+   */
-
+  subtreeContainsEditing: Set<string>;
-const treeContainsSessionId = (node: SessionNode, sessionId: string | null): boolean => {
+  /**
-  if (!sessionId) {
+   * Precomputed session ID of the row whose sidebar menu is open, or null
-    return false;
+   * if no menu is open. Only one row can have its menu open at a time.
-  }
+   */
-
+  menuOpenSessionId: string | null;
-  if (node.session.id === sessionId) {
+  /**
-    return true;
+   * Precomputed structural key for this node. Encodes the IDs and child
-  }
+   * counts of all descendants so a reference-only change to `node` (e.g.
-
+   * a fresh tree rebuild) can be detected with a single string compare
-  for (const child of node.children) {
+   * instead of a recursive walk per row.
-    if (treeContainsSessionId(child, sessionId)) {
+   */
-      return true;
+  nodeStructureKey: string;
-    }
+  /**
-  }
+   * Resolves the per-row render extras for each child node. SessionGroupSection
-
+   * walks the whole tree once to precompute the structure key for every
-  return false;
+   * descendant; SessionNodeItem's recursive child render uses this lookup
-};
+   * to fetch the right key for each child it produces.
-
+   */
-const treeContainsMenuKey = (
+  childRenderExtrasFor?: (child: SessionNode) => SessionNodeChildRenderExtras;
-  node: SessionNode,
+  /**
-  menuKey: string | null,
+   * Batched index of live session objects keyed by id. The previous
-  renderContext: 'project' | 'recent',
+   * implementation called `useSession(session.id)` per row, which used
-  archivedBucket: boolean,
+   * `findLiveSession` to iterate every child-store on every SSE event.
-): boolean => {
+   * With M visible rows that's M×child-stores per event; the batched
-  if (!menuKey) {
+   * map turns it into a single Map.get per row. The parent falls back
-    return false;
+   * to `useSession` only when this map returns undefined.
-  }
+   */
-
+  liveSessionById: Map<string, Session>;
  const nodeMenuKey = `${renderContext}:${archivedBucket ? 'archived' : 'active'}:${node.session.id}`;
  if (nodeMenuKey === menuKey) {
    return true;
  }
  for (const child of node.children) {
    if (treeContainsMenuKey(child, menuKey, renderContext, archivedBucket)) {
      return true;
    }
  }
  return false;
 };
 const areEqual = (prev: Props, next: Props): boolean => {
  const prevSession = prev.node.session;
  const nextSession = next.node.session;
  const prevSessionId = prevSession.id;
  const nextSessionId = nextSession.id;
  if (prevSessionId !== nextSessionId) return false;
  if (prev.node.session !== next.node.session) return false;
  if (getNodeChildSignature(prev.node) !== getNodeChildSignature(next.node)) return false;
  if (prev.depth !== next.depth) return false;
  if (prev.groupDirectory !== next.groupDirectory) return false;
  if (prev.projectId !== next.projectId) return false;
  if (prev.archivedBucket !== next.archivedBucket) return false;
  if (prev.currentSessionId !== next.currentSessionId) {
    const prevActiveInTree = treeContainsSessionId(prev.node, prev.currentSessionId);
    const nextActiveInTree = treeContainsSessionId(next.node, next.currentSessionId);
    if (prevActiveInTree || nextActiveInTree) {
      return false;
    }
  }
  if (prev.pinnedSessionIds.has(prevSessionId) !== next.pinnedSessionIds.has(nextSessionId)) return false;
  // Expansion is keyed per render context, so compare the composite key
  // matching the one isExpanded reads from in render. If a session appears
  // in two contexts (project + recent), they have independent state.
  {
    const prevRenderContext = prev.renderContext ?? 'project';
    const nextRenderContext = next.renderContext ?? 'project';
    const prevArchived = prev.archivedBucket ?? false;
    const nextArchived = next.archivedBucket ?? false;
    const prevExpansionKey = `${prevRenderContext}:${prevArchived ? 'archived' : 'active'}:${prevSessionId}`;
    const nextExpansionKey = `${nextRenderContext}:${nextArchived ? 'archived' : 'active'}:${nextSessionId}`;
    if (prev.expandedParents.has(prevExpansionKey) !== next.expandedParents.has(nextExpansionKey)) return false;
  }
  if (prev.hasSessionSearchQuery !== next.hasSessionSearchQuery) return false;
  if (prev.normalizedSessionSearchQuery !== next.normalizedSessionSearchQuery) return false;
  if (prev.notifyOnSubtasks !== next.notifyOnSubtasks) return false;
  if (prev.editingId !== next.editingId) {
    const prevEditingInTree = treeContainsSessionId(prev.node, prev.editingId);
    const nextEditingInTree = treeContainsSessionId(next.node, next.editingId);
    if (prevEditingInTree || nextEditingInTree) {
      return false;
    }
  }
  if (prev.editTitle !== next.editTitle) {
    const prevEditingInTree = treeContainsSessionId(prev.node, prev.editingId);
    const nextEditingInTree = treeContainsSessionId(next.node, next.editingId);
    if (prevEditingInTree || nextEditingInTree) {
      return false;
    }
  }
  if ((prev.copiedSessionId === prevSessionId) !== (next.copiedSessionId === nextSessionId)) return false;
  const prevMenuInTree = treeContainsMenuKey(prev.node, prev.openSidebarMenuKey, prev.renderContext ?? 'project', prev.archivedBucket ?? false);
  const nextMenuInTree = treeContainsMenuKey(next.node, next.openSidebarMenuKey, next.renderContext ?? 'project', next.archivedBucket ?? false);
  if (prevMenuInTree !== nextMenuInTree) return false;
  const prevDirectory = normalizePath((prevSession as Session & { directory?: string | null }).directory ?? null)
    ?? normalizePath(prev.groupDirectory ?? null);
  const nextDirectory = normalizePath((nextSession as Session & { directory?: string | null }).directory ?? null)
    ?? normalizePath(next.groupDirectory ?? null);
  if (prevDirectory !== nextDirectory) return false;
  if ((prev.secondaryMeta?.projectLabel ?? null) !== (next.secondaryMeta?.projectLabel ?? null)) return false;
  if ((prev.secondaryMeta?.branchLabel ?? null) !== (next.secondaryMeta?.branchLabel ?? null)) return false;
  if (prev.mobileVariant !== next.mobileVariant) return false;
  if (prev.alwaysShowActions !== next.alwaysShowActions) return false;
  if ((prev.renderContext ?? 'project') !== (next.renderContext ?? 'project')) return false;
  if (prev.renamingFolderId !== next.renamingFolderId) return false;
  return true;
 };
 function SessionNodeItemComponent(props: Props): React.ReactNode {
@@ -255,6 +182,11 @@ function SessionNodeItemComponent(props: Props): React.ReactNode {
    renderSessionNode,
    secondaryMeta,
    renderContext = 'project',
    subtreeContainsActive,
    subtreeContainsEditing,
    menuOpenSessionId,
    childRenderExtrasFor,
    liveSessionById,
  } = props;
  const hasSecondaryProjectLabel = Boolean(secondaryMeta?.projectLabel);
  const hasSecondaryBranchLabel = Boolean(secondaryMeta?.branchLabel);
@@ -302,11 +234,21 @@ function SessionNodeItemComponent(props: Props): React.ReactNode {
  const pendingRenameRef = React.useRef<{ id: string; title: string } | null>(null);
  const handleSaveEditRef = React.useRef(handleSaveEdit);
  handleSaveEditRef.current = handleSaveEdit;
  const [renameDraft, setRenameDraft] = React.useState(editTitle);
  const renameDraftRef = React.useRef(renameDraft);
  renameDraftRef.current = renameDraft;
  const renameTargetRef = React.useRef<string | null>(null);
  const formRef = React.useRef<HTMLFormElement>(null);
  const session = node.session;
-  const liveSession = useSession(session.id);
+  // Batched live-session lookup. `liveSessionById` is built once per
-  const resolvedSession = liveSession ?? session;
+  // Sidebar render from the same `useAllLiveSessions` selector that
  // `useSession` would have iterated per child-store, so a Map.get
  // here is equivalent in observed state but O(1) per row instead of
  // O(child-stores). Falls back to the row session when the live map
  // hasn't seen this id yet (sub-render latency between when a session
  // is created and when the SSE-driven aggregate picks it up).
  const resolvedSession = liveSessionById.get(session.id) ?? session;
  const sessionDirectory =
    normalizePath((session as Session & { directory?: string | null }).directory ?? null)
@@ -477,13 +419,25 @@ function SessionNodeItemComponent(props: Props): React.ReactNode {
    if (editingId !== session.id) return;
    const handleDocMouseDown = (e: MouseEvent) => {
      if (formRef.current && !formRef.current.contains(e.target as Node)) {
-        handleSaveEditRef.current();
+        handleSaveEditRef.current(renameDraftRef.current);
      }
    };
    document.addEventListener('mousedown', handleDocMouseDown);
    return () => document.removeEventListener('mousedown', handleDocMouseDown);
  }, [editingId, session.id]);
  React.useLayoutEffect(() => {
    if (editingId !== session.id) {
      if (renameTargetRef.current === session.id) {
        renameTargetRef.current = null;
      }
      return;
    }
    if (renameTargetRef.current === session.id) return;
    renameTargetRef.current = session.id;
    setRenameDraft(editTitle);
  }, [editingId, editTitle, session.id]);
  if (editingId === session.id) {
    return (
      <div
@@ -496,24 +450,21 @@ function SessionNodeItemComponent(props: Props): React.ReactNode {
            className="flex w-full items-center gap-2"
            onSubmit={(event) => {
              event.preventDefault();
-              handleSaveEdit();
+              handleSaveEdit(renameDraft);
            }}
          >
            <input
-              value={editTitle}
+              value={renameDraft}
-              onChange={(event) => setEditTitle(event.target.value)}
+              onChange={(event) => setRenameDraft(event.target.value)}
              className="flex-1 min-w-0 bg-transparent typography-ui-label outline-none placeholder:text-muted-foreground"
              autoFocus
              placeholder={t('sessions.sidebar.session.menu.rename')}
              onKeyDown={(event) => {
                event.stopPropagation();
                if (event.key === 'Escape') {
                  event.stopPropagation();
                  handleCancelEdit();
                  return;
                }
                if (event.key === ' ' || event.key === 'Enter') {
                  event.stopPropagation();
                }
              }}
            />
            <button
@@ -1030,18 +981,18 @@ function SessionNodeItemComponent(props: Props): React.ReactNode {
            ) : (
              <button
                type="button"
- 	                onPointerDown={handleRowPointerDown}
+	                onPointerDown={handleRowPointerDown}
- 	                onPointerUp={handleRowPointerEnd}
+	                onPointerUp={handleRowPointerEnd}
- 	                onPointerCancel={handleRowPointerEnd}
+	                onPointerCancel={handleRowPointerEnd}
- 	                onMouseDown={handleRowMouseDown}
+	                onMouseDown={handleRowMouseDown}
- 	                onClick={(event) => handleRowSelect(event)}
+	                onClick={(event) => handleRowSelect(event)}
                onDoubleClick={(e) => {
                  e.stopPropagation();
                  handleSessionDoubleClick(session.id, sessionTitle);
                }}
                className={cn(
-  	                  'flex min-w-0 flex-1 cursor-pointer flex-col gap-0 overflow-hidden rounded-md text-left focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-primary/50 text-foreground select-none transition-[padding]',
+	                  'flex min-w-0 flex-1 cursor-pointer flex-col gap-0 overflow-hidden rounded-md text-left focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-primary/50 text-foreground select-none transition-[padding]',
-  	                  isTouchPressed && 'bg-interactive-hover/70',
+	                  isTouchPressed && 'bg-interactive-hover/70',
                  alwaysShowActions
                    ? (isVSCode ? revealPaddingClass : alwaysActionPaddingClass)
                    : revealPaddingClass
@@ -1159,7 +1110,26 @@ function SessionNodeItemComponent(props: Props): React.ReactNode {
        </ContextMenu.Root>
      </DraggableSessionRow>
      {hasChildren && isExpanded
-        ? node.children.map((child) => renderSessionNode(child, depth + 1, sessionDirectory ?? groupDirectory, projectId, archivedBucket, undefined, renderContext))
+        ? node.children.map((child): React.ReactNode => {
          const childRenderExtras: SessionNodeChildRenderExtras = childRenderExtrasFor
            ? childRenderExtrasFor(child)
            : {
                subtreeContainsActive,
                subtreeContainsEditing,
                menuOpenSessionId,
                nodeStructureKey: '',
              };
          return renderSessionNode(
            child,
            depth + 1,
            sessionDirectory ?? groupDirectory,
            projectId,
            archivedBucket,
            undefined,
            renderContext,
            childRenderExtras,
          );
        })
        : null}
      <Dialog open={exportDialogOpen} onOpenChange={setExportDialogOpen}>
        <DialogContent showCloseButton={false} className="max-w-sm gap-5">
@@ -1213,4 +1183,194 @@ function SessionNodeItemComponent(props: Props): React.ReactNode {
  );
 }
-export const SessionNodeItem = React.memo(SessionNodeItemComponent, areEqual);
+const getNodeSessionDirectory = (node: SessionNode): string | null => {
  return normalizePath((node.session as Session & { directory?: string | null }).directory ?? null);
 };
 const isSecondaryMetaEqual = (prev?: SecondaryMeta | null, next?: SecondaryMeta | null): boolean => {
  return (prev?.projectLabel ?? null) === (next?.projectLabel ?? null)
    && (prev?.branchLabel ?? null) === (next?.branchLabel ?? null);
 };
 const getMenuSessionIdFromKey = (props: Props): string | null => {
  if (!props.openSidebarMenuKey) return null;
  const bucketTag = props.archivedBucket ? 'archived' : 'active';
  const prefix = `${props.renderContext ?? 'project'}:${bucketTag}:`;
  return props.openSidebarMenuKey.startsWith(prefix)
    ? props.openSidebarMenuKey.slice(prefix.length)
    : null;
 };
 const getRelevantMenuSessionId = (props: Props): string | null => {
  return props.menuOpenSessionId ?? getMenuSessionIdFromKey(props);
 };
 const subtreeContainsSession = (
  props: Props,
  sessionId: string | null,
  precomputed: Set<string>,
 ): boolean => {
  if (!sessionId) return false;
  if (precomputed.has(props.node.session.id)) return true;
  return nodeContainsSessionId(props.node, sessionId);
 };
 const hasSetMembershipChangeInNode = (
  prevNode: SessionNode,
  nextNode: SessionNode,
  prevSet: Set<string>,
  nextSet: Set<string>,
  getKey: (node: SessionNode) => string,
 ): boolean => {
  if (prevNode.session.id !== nextNode.session.id) return true;
  const key = getKey(prevNode);
  if (prevSet.has(key) !== nextSet.has(key)) return true;
  if (prevNode.children.length !== nextNode.children.length) return true;
  for (let i = 0; i < prevNode.children.length; i += 1) {
    if (hasSetMembershipChangeInNode(prevNode.children[i], nextNode.children[i], prevSet, nextSet, getKey)) {
      return true;
    }
  }
  return false;
 };
 const hasResolvedSessionChangeInNode = (
  prevNode: SessionNode,
  nextNode: SessionNode,
  prevLiveSessionById: Map<string, Session>,
  nextLiveSessionById: Map<string, Session>,
 ): boolean => {
  if (prevNode.session.id !== nextNode.session.id) return true;
  const sessionId = prevNode.session.id;
  if ((prevLiveSessionById.get(sessionId) ?? prevNode.session) !== (nextLiveSessionById.get(sessionId) ?? nextNode.session)) {
    return true;
  }
  if (prevNode.children.length !== nextNode.children.length) return true;
  for (let i = 0; i < prevNode.children.length; i += 1) {
    if (hasResolvedSessionChangeInNode(prevNode.children[i], nextNode.children[i], prevLiveSessionById, nextLiveSessionById)) {
      return true;
    }
  }
  return false;
 };
 const hasExpansionMembershipChange = (prev: Props, next: Props): boolean => {
  if (prev.hasSessionSearchQuery || next.hasSessionSearchQuery) return false;
  const prevBucketTag = prev.archivedBucket ? 'archived' : 'active';
  const nextBucketTag = next.archivedBucket ? 'archived' : 'active';
  return hasSetMembershipChangeInNode(
    prev.node,
    next.node,
    prev.expandedParents,
    next.expandedParents,
    (node) => `${prev.renderContext ?? 'project'}:${prevBucketTag}:${node.session.id}`,
  ) || hasSetMembershipChangeInNode(
    prev.node,
    next.node,
    prev.expandedParents,
    next.expandedParents,
    (node) => `${next.renderContext ?? 'project'}:${nextBucketTag}:${node.session.id}`,
  );
 };
 const areSessionNodeItemPropsEqual = (prev: Props, next: Props): boolean => {
  if (prev.node.session.id !== next.node.session.id) return false;
  if (prev.depth !== next.depth) return false;
  if (prev.groupDirectory !== next.groupDirectory) return false;
  if (prev.projectId !== next.projectId) return false;
  if (prev.archivedBucket !== next.archivedBucket) return false;
  if ((prev.renderContext ?? 'project') !== (next.renderContext ?? 'project')) return false;
  if (prev.mobileVariant !== next.mobileVariant) return false;
  if (prev.alwaysShowActions !== next.alwaysShowActions) return false;
  if (prev.hasSessionSearchQuery !== next.hasSessionSearchQuery) return false;
  if (prev.normalizedSessionSearchQuery !== next.normalizedSessionSearchQuery) return false;
  if (prev.notifyOnSubtasks !== next.notifyOnSubtasks) return false;
  if (prev.nodeStructureKey !== next.nodeStructureKey) return false;
  if (getNodeSessionDirectory(prev.node) !== getNodeSessionDirectory(next.node)) return false;
  if (!isSecondaryMetaEqual(prev.secondaryMeta, next.secondaryMeta)) return false;
  if (prev.liveSessionById !== next.liveSessionById
    && hasResolvedSessionChangeInNode(prev.node, next.node, prev.liveSessionById, next.liveSessionById)) {
    return false;
  }
  if (prev.pinnedSessionIds !== next.pinnedSessionIds
    && hasSetMembershipChangeInNode(prev.node, next.node, prev.pinnedSessionIds, next.pinnedSessionIds, (node) => node.session.id)) {
    return false;
  }
  if (prev.expandedParents !== next.expandedParents && hasExpansionMembershipChange(prev, next)) {
    return false;
  }
  if (prev.currentSessionId !== next.currentSessionId
    && (
      subtreeContainsSession(prev, prev.currentSessionId, prev.subtreeContainsActive)
      || subtreeContainsSession(next, next.currentSessionId, next.subtreeContainsActive)
    )) {
    return false;
  }
  if (prev.editingId !== next.editingId
    && (
      subtreeContainsSession(prev, prev.editingId, prev.subtreeContainsEditing)
      || subtreeContainsSession(next, next.editingId, next.subtreeContainsEditing)
    )) {
    return false;
  }
  if (prev.editTitle !== next.editTitle
    && (
      subtreeContainsSession(prev, prev.editingId, prev.subtreeContainsEditing)
      || subtreeContainsSession(next, next.editingId, next.subtreeContainsEditing)
    )) {
    return false;
  }
  if (prev.copiedSessionId !== next.copiedSessionId
    && (
      nodeContainsSessionId(prev.node, prev.copiedSessionId)
      || nodeContainsSessionId(next.node, next.copiedSessionId)
    )) {
    return false;
  }
  if (prev.openSidebarMenuKey !== next.openSidebarMenuKey) {
    const prevMenuSessionId = getRelevantMenuSessionId(prev);
    const nextMenuSessionId = getRelevantMenuSessionId(next);
    if (nodeContainsSessionId(prev.node, prevMenuSessionId) || nodeContainsSessionId(next.node, nextMenuSessionId)) {
      return false;
    }
  }
  if (prev.renamingFolderId !== next.renamingFolderId) {
    const prevMenuSessionId = getRelevantMenuSessionId(prev);
    const nextMenuSessionId = getRelevantMenuSessionId(next);
    if (nodeContainsSessionId(prev.node, prevMenuSessionId) || nodeContainsSessionId(next.node, nextMenuSessionId)) {
      return false;
    }
  }
  return prev.setEditingId === next.setEditingId
    && prev.setEditTitle === next.setEditTitle
    && prev.handleSaveEdit === next.handleSaveEdit
    && prev.handleCancelEdit === next.handleCancelEdit
    && prev.toggleParent === next.toggleParent
    && prev.handleSessionSelect === next.handleSessionSelect
    && prev.handleSessionDoubleClick === next.handleSessionDoubleClick
    && prev.togglePinnedSession === next.togglePinnedSession
    && prev.handleShareSession === next.handleShareSession
    && prev.handleCopyShareUrl === next.handleCopyShareUrl
    && prev.handleUnshareSession === next.handleUnshareSession
    && prev.setOpenSidebarMenuKey === next.setOpenSidebarMenuKey
    && prev.getFoldersForScope === next.getFoldersForScope
    && prev.getSessionFolderId === next.getSessionFolderId
    && prev.removeSessionFromFolder === next.removeSessionFromFolder
    && prev.addSessionToFolder === next.addSessionToFolder
    && prev.createFolderAndStartRename === next.createFolderAndStartRename
    && prev.openContextPanelTab === next.openContextPanelTab
    && prev.handleDeleteSession === next.handleDeleteSession
    && prev.renderSessionNode === next.renderSessionNode;
 };
 export const SessionNodeItem = React.memo(SessionNodeItemComponent, areSessionNodeItemPropsEqual);
@@ -3,6 +3,12 @@ import { cn } from '@/lib/utils';
 import type { SessionNode } from './types';
 import { useI18n } from '@/lib/i18n';
 import { Icon } from "@/components/icon/Icon";
 import {
  collectSubtreeContainingId,
  computeNodeStructureKey,
  resolveMenuOpenSessionId,
 } from './sessionNodeItemUtils';
 import type { SessionNodeRenderExtras } from './sessionNodeItemUtils';
 type ActivityItem = {
  node: SessionNode;
@@ -22,17 +28,34 @@ type ActivitySection = {
 type Props = {
  sections: ActivitySection[];
-  renderSessionNode: (node: SessionNode, depth?: number, groupDirectory?: string | null, projectId?: string | null, archivedBucket?: boolean, secondaryMeta?: { projectLabel?: string | null; branchLabel?: string | null } | null, renderContext?: 'project' | 'recent') => React.ReactNode;
+  renderSessionNode: (
    node: SessionNode,
    depth?: number,
    groupDirectory?: string | null,
    projectId?: string | null,
    archivedBucket?: boolean,
    secondaryMeta?: { projectLabel?: string | null; branchLabel?: string | null } | null,
    renderContext?: 'project' | 'recent',
    renderExtras?: SessionNodeRenderExtras,
  ) => React.ReactNode;
  currentSessionId: string | null;
  editingId: string | null;
  openSidebarMenuKey: string | null;
  variant?: 'section' | 'flat';
  initialVisibleCount?: number;
  batchSize?: number;
 };
 type RenderExtras = SessionNodeRenderExtras;
 const MAX_VISIBLE_RECENT_SESSIONS = 7;
 export function SidebarActivitySections({
  sections,
  renderSessionNode,
  currentSessionId,
  editingId,
  openSidebarMenuKey,
  variant = 'section',
  initialVisibleCount = MAX_VISIBLE_RECENT_SESSIONS,
  batchSize = MAX_VISIBLE_RECENT_SESSIONS,
@@ -77,6 +100,36 @@ export function SidebarActivitySections({
    });
  }, [batchSize]);
  const buildRenderExtras = React.useCallback((nodes: SessionNode[]) => {
    const subtreeContainsActive = new Set<string>();
    collectSubtreeContainingId(nodes, currentSessionId, subtreeContainsActive);
    const subtreeContainsEditing = new Set<string>();
    collectSubtreeContainingId(nodes, editingId, subtreeContainsEditing);
    const menuOpenSessionId = resolveMenuOpenSessionId(nodes, openSidebarMenuKey, 'recent', false);
    const nodeStructureKeyByNode = new WeakMap<SessionNode, string>();
    const visit = (node: SessionNode): void => {
      nodeStructureKeyByNode.set(node, computeNodeStructureKey(node));
      node.children.forEach(visit);
    };
    nodes.forEach(visit);
    const childRenderExtrasFor = (child: SessionNode): RenderExtras => ({
      subtreeContainsActive,
      subtreeContainsEditing,
      menuOpenSessionId,
      nodeStructureKey: nodeStructureKeyByNode.get(child) ?? '',
      childRenderExtrasFor,
    });
    return (node: SessionNode): RenderExtras => ({
      subtreeContainsActive,
      subtreeContainsEditing,
      menuOpenSessionId,
      nodeStructureKey: nodeStructureKeyByNode.get(node) ?? '',
      childRenderExtrasFor,
    });
  }, [currentSessionId, editingId, openSidebarMenuKey]);
  const visibleSections = sections.filter((section) => section.items.length > 0);
  if (visibleSections.length === 0) {
    return null;
@@ -93,11 +146,22 @@ export function SidebarActivitySections({
        const visibleItems = section.items.slice(0, visibleLimit);
        const remainingCount = section.items.length - visibleItems.length;
        const canShowFewer = !flatVariant && section.items.length > initialVisibleCount && remainingCount === 0;
        const getRenderExtras = buildRenderExtras(visibleItems.map((item) => item.node));
        const renderItem = (item: ActivityItem) => renderSessionNode(
          item.node,
          0,
          item.groupDirectory,
          item.projectId,
          false,
          item.secondaryMeta,
          'recent',
          getRenderExtras(item.node),
        );
        if (flatVariant) {
          return (
            <div key={section.key} className="space-y-0.5">
-              {visibleItems.map((item) => renderSessionNode(item.node, 0, item.groupDirectory, item.projectId, false, item.secondaryMeta, 'recent'))}
+              {visibleItems.map(renderItem)}
              {remainingCount > 0 ? (
                <button
                  type="button"
@@ -126,7 +190,7 @@ export function SidebarActivitySections({
            </button>
            {!isCollapsed ? (
              <div className={cn('space-y-0.5 pl-7')}>
-                {visibleItems.map((item) => renderSessionNode(item.node, 0, item.groupDirectory, item.projectId, false, item.secondaryMeta, 'recent'))}
+                {visibleItems.map(renderItem)}
                {remainingCount > 0 ? (
                  <button
                    type="button"
@@ -42,7 +42,15 @@ type Props = {
  hasSessionSearchQuery: boolean;
  emptyState: React.ReactNode;
  searchEmptyState: React.ReactNode;
-  renderGroupSessions: (group: SessionGroup, groupKey: string, projectId?: string | null, hideGroupLabel?: boolean, dragHandleProps?: SortableDragHandleProps | null, compactBodyPadding?: boolean) => React.ReactNode;
+  renderGroupSessions: (
    group: SessionGroup,
    groupKey: string,
    projectId?: string | null,
    hideGroupLabel?: boolean,
    dragHandleProps?: SortableDragHandleProps | null,
    compactBodyPadding?: boolean,
    scrollContainerRef?: React.RefObject<HTMLElement | null>,
  ) => React.ReactNode;
  homeDirectory: string | null;
  collapsedProjects: Set<string>;
  hideDirectoryControls: boolean;
@@ -78,6 +86,39 @@ export function SidebarProjectsList(props: Props): React.ReactNode {
    useSensor(PointerSensor, { activationConstraint: { distance: 8 } }),
  );
  // Threaded into SessionGroupSection so the archived-bucket virtualizer
  // can resolve the scrolling ancestor synchronously (no getComputedStyle
  // walk) and skip the cost of a style recalc on every render.
  const scrollContainerRef = React.useRef<HTMLElement | null>(null);
  // Memoize the result of getOrderedGroups. The callback is stable
  // (deps: [groupOrderByProject]) and `section.groups` is a stable
  // reference from useSessionSidebarSections, but the caller discards
  // the result on every render and the callback allocates a new array
  // each time. With many projects and many sidebar re-renders this
  // builds O(P) arrays per render. The cache returns the same array
  // reference when the inputs haven't changed, so the downstream
  // orderedGroups.filter/find work and any consumer-memoization see a
  // stable reference.
  const orderedGroupsCacheRef = React.useRef<Map<string, { groups: SessionGroup[]; ordered: SessionGroup[] }>>(new Map());
  const cachedGetOrderedGroups = (projectId: string, groups: SessionGroup[]): SessionGroup[] => {
    const cache = orderedGroupsCacheRef.current;
    const hit = cache.get(projectId);
    if (hit && hit.groups === groups) {
      return hit.ordered;
    }
    const ordered = props.getOrderedGroups(projectId, groups);
    cache.set(projectId, { groups, ordered });
    // Bound the cache so re-ordering projects (which replaces the
    // projects list and invalidates every projectId) doesn't grow
    // unboundedly.
    if (cache.size > 256) {
      const firstKey = cache.keys().next().value;
      if (firstKey !== undefined) cache.delete(firstKey);
    }
    return ordered;
  };
  if (props.sharedSessionsOnly) {
    return (
      <ScrollableOverlay useScrollShadow scrollShadowSize={96} outerClassName="flex-1 min-h-0" className={cn('space-y-1 pb-1 pr-2', props.mobileVariant ? '' : '')}>
@@ -96,7 +137,7 @@ export function SidebarProjectsList(props: Props): React.ReactNode {
  }
  return (
-    <ScrollableOverlay useScrollShadow scrollShadowSize={96} outerClassName="flex-1 min-h-0" className={cn('space-y-1 pb-1 pl-2.5 pr-2', props.mobileVariant ? '' : '')}>
+    <ScrollableOverlay ref={scrollContainerRef} useScrollShadow scrollShadowSize={96} outerClassName="flex-1 min-h-0" className={cn('space-y-1 pb-1 pl-2.5 pr-2', props.mobileVariant ? '' : '')}>
      {props.topContent}
      {props.showOnlyMainWorkspace ? (
        <div className="space-y-[0.6rem] py-1">
@@ -124,7 +165,7 @@ export function SidebarProjectsList(props: Props): React.ReactNode {
              const hideGroupLabel = group.id === primaryGroup.id;
              return (
                <React.Fragment key={groupKey}>
-                  {props.renderGroupSessions(group, groupKey, activeSection.project.id, hideGroupLabel, null, true)}
+                  {props.renderGroupSessions(group, groupKey, activeSection.project.id, hideGroupLabel, null, true, scrollContainerRef)}
                </React.Fragment>
              );
            });
@@ -158,7 +199,7 @@ export function SidebarProjectsList(props: Props): React.ReactNode {
                const isCollapsed = props.collapsedProjects.has(projectKey);
                const isActiveProject = projectKey === props.activeProjectId;
                const isRepo = props.projectRepoStatus.get(projectKey);
-                const orderedGroups = props.getOrderedGroups(projectKey, section.groups);
+                const orderedGroups = cachedGetOrderedGroups(projectKey, section.groups);
                const rootGroup = orderedGroups.find((group) => group.isMain) ?? null;
                const nestedGroups = rootGroup
                  ? orderedGroups.filter((group) => group.id !== rootGroup.id)
@@ -223,13 +264,13 @@ export function SidebarProjectsList(props: Props): React.ReactNode {
                              });
                            }}
                          >
-                            {rootGroup ? props.renderGroupSessions(rootGroup, `${projectKey}:${rootGroup.id}`, projectKey, true) : null}
+                            {rootGroup ? props.renderGroupSessions(rootGroup, `${projectKey}:${rootGroup.id}`, projectKey, true, null, undefined, scrollContainerRef) : null}
                            <SortableContext items={nestedGroups.map((group) => group.id)} strategy={verticalListSortingStrategy}>
                              {nestedGroups.map((group) => {
                                const groupKey = `${projectKey}:${group.id}`;
                                return (
                                  <SortableGroupItem key={group.id} id={group.id} disabled={props.isInlineEditing}>
-                                    {(dragHandleProps) => props.renderGroupSessions(group, groupKey, projectKey, false, dragHandleProps)}
+                                    {(dragHandleProps) => props.renderGroupSessions(group, groupKey, projectKey, false, dragHandleProps, undefined, scrollContainerRef)}
                                  </SortableGroupItem>
                                );
                              })}
@@ -61,6 +61,16 @@ export const useProjectRepoStatus = (args: Args): void => {
  // any single project's branch settles (the old N² cascade).
  const resolvedInputKeyByProjectId = React.useRef<Map<string, string>>(new Map());
  // TTL cache: when a project's `gitRepoStatus` refreshes (it can fire on
  // every background poll even if the branch is unchanged), skip the
  // `getRootBranch` re-resolution if we resolved the same input within
  // the TTL window. 5 minutes matches the polling interval that typically
  // drives these refreshes, so we always serve cached results on
  // background updates and only re-resolve on cold start or actual
  // branch changes (those still invalidate via the input-key check).
  const rootBranchCacheRef = React.useRef<Map<string, { branch: string; at: number }>>(new Map());
  const ROOT_BRANCH_TTL_MS = 5 * 60_000;
  React.useEffect(() => {
    let cancelled = false;
@@ -73,13 +83,16 @@ export const useProjectRepoStatus = (args: Args): void => {
        for (const id of resolvedInputKeyByProjectId.current.keys()) {
          if (!validIds.has(id)) {
            resolvedInputKeyByProjectId.current.delete(id);
            rootBranchCacheRef.current.delete(id);
          }
        }
        const now = Date.now();
        const pending = normalizedProjects.filter((project) => {
          const status = gitRepoStatus.get(project.normalizedPath);
          if (status?.isGitRepo === false) {
            resolvedInputKeyByProjectId.current.delete(project.id);
            rootBranchCacheRef.current.delete(project.id);
            return false;
          }
          if (status?.isGitRepo !== true || status.branch === null) {
@@ -88,7 +101,21 @@ export const useProjectRepoStatus = (args: Args): void => {
          const currentBranch = status.branch.trim();
          const currentInputKey = `${project.normalizedPath}\0${currentBranch}`;
          const lastInputKey = resolvedInputKeyByProjectId.current.get(project.id);
-          return lastInputKey === undefined || lastInputKey !== currentInputKey;
+          if (lastInputKey === currentInputKey) {
            // We've already resolved this exact (path, branch) pair.
            // The TTL cache is just an extra protection for the case
            // where the input key was reset by a transient blip —
            // keep the existing map entry fresh so future re-renders
            // hit the cache instead of refetching.
            const cached = rootBranchCacheRef.current.get(project.id);
            if (cached) cached.at = now;
            return false;
          }
          // Same input? Serve from TTL cache if it's still warm.
          if (lastInputKey !== undefined && now - (rootBranchCacheRef.current.get(project.id)?.at ?? 0) < ROOT_BRANCH_TTL_MS) {
            return false;
          }
          return true;
        });
        if (pending.length === 0) {
@@ -113,6 +140,7 @@ export const useProjectRepoStatus = (args: Args): void => {
          return;
        }
        const nowAfter = Date.now();
        setProjectRootBranches((prev) => {
          const next = new Map(prev);
          resolved.forEach(({ id, branch }) => {
@@ -122,8 +150,11 @@ export const useProjectRepoStatus = (args: Args): void => {
          });
          return next;
        });
-        resolved.forEach(({ id, inputKey }) => {
+        resolved.forEach(({ id, inputKey, branch }) => {
          resolvedInputKeyByProjectId.current.set(id, inputKey);
          if (branch) {
            rootBranchCacheRef.current.set(id, { branch, at: nowAfter });
          }
        });
      };
      void run();
@@ -133,5 +164,9 @@ export const useProjectRepoStatus = (args: Args): void => {
      cancelled = true;
      clearTimeout(timer);
    };
    // ROOT_BRANCH_TTL_MS is a module-level constant; intentionally not
    // in the deps array since it never changes during the component
    // lifetime.
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [normalizedProjects, projectGitBranchesKey, gitRepoStatus, setProjectRootBranches]);
 };
@@ -5,11 +5,22 @@ import { dedupeSessionsById, isSessionRelatedToProject, normalizePath } from '..
 type WorktreeMeta = { path: string };
 type NormalizedProject = { id: string; normalizedPath: string };
 type Args = {
  isVSCode: boolean;
  sessions: Session[];
  archivedSessions: Session[];
  availableWorktreesByProject: Map<string, WorktreeMeta[]>;
  /**
   * The set of normalized projects the sidebar will render. Used in
   * Layer 4.13 to precompute the allowed directory set so the per-row
   * `sessionsByDirectory` Map only contains buckets the sidebar will
   * actually consume. With 10 projects × 5 worktrees and 100 sessions
   * per directory this drops the Map from N entries to the small
   * subset the sidebar needs.
   */
  normalizedProjects: NormalizedProject[];
 };
 export const useProjectSessionLists = (args: Args) => {
@@ -18,8 +29,32 @@ export const useProjectSessionLists = (args: Args) => {
    sessions,
    archivedSessions,
    availableWorktreesByProject,
    normalizedProjects,
  } = args;
  // Precompute the set of directories the sidebar will ever ask about:
  // every project's normalized path plus the path of each registered
  // worktree. Walking this set is O(P + W) per Sidebar render and lets
  // us skip the bulk of `sessions` (whose directory is not associated
  // with a known project) when building `sessionsByDirectory`.
  const allowedDirectories = React.useMemo(() => {
    const set = new Set<string>();
    normalizedProjects.forEach((project) => {
      if (project.normalizedPath) {
        set.add(project.normalizedPath);
      }
    });
    if (!isVSCode) {
      for (const worktrees of availableWorktreesByProject.values()) {
        for (const worktree of worktrees) {
          const normalized = normalizePath(worktree.path);
          if (normalized) set.add(normalized);
        }
      }
    }
    return set;
  }, [normalizedProjects, availableWorktreesByProject, isVSCode]);
  const sessionsByDirectory = React.useMemo(() => {
    const next = new Map<string, Session[]>();
    sessions.forEach((session) => {
@@ -27,13 +62,21 @@ export const useProjectSessionLists = (args: Args) => {
      if (!directory) {
        return;
      }
      // Skip sessions whose directory doesn't belong to any known
      // project or worktree. Without this filter the Map grows with
      // every session the server has ever seen, even ones for
      // long-removed worktrees; the sidebar's downstream filters
      // would then drop them anyway.
      if (!allowedDirectories.has(directory)) {
        return;
      }
      const collection = next.get(directory) ?? [];
      collection.push(session);
      next.set(directory, collection);
    });
    return next;
-  }, [sessions]);
+  }, [sessions, allowedDirectories]);
  const getSessionsForProject = React.useCallback(
    (project: { normalizedPath: string }) => {
@@ -22,11 +22,9 @@ type Args = {
  openNewSessionDraft: (options?: { directoryOverride?: string | null }) => void;
  setActiveMainTab: (tab: MainTab) => void;
  setSessionSwitcherOpen: (open: boolean) => void;
  sessions: Session[];
  worktreeMetadata: Map<string, { path?: string | null }>;
 };
-export const useProjectSessionSelection = (args: Args): { currentSessionDirectory: string | null } => {
+export const useProjectSessionSelection = (args: Args): void => {
  const {
    projectSections,
    activeProjectId,
@@ -39,8 +37,6 @@ export const useProjectSessionSelection = (args: Args): { currentSessionDirector
    openNewSessionDraft,
    setActiveMainTab,
    setSessionSwitcherOpen,
    sessions,
    worktreeMetadata,
  } = args;
  const projectSessionMeta = React.useMemo(() => {
@@ -101,6 +97,7 @@ export const useProjectSessionSelection = (args: Args): { currentSessionDirector
    if (previousActiveProjectRef.current === activeProjectId) {
      return;
    }
    const section = projectSections.find((item) => item.project.id === activeProjectId);
    if (!section) {
      return;
@@ -173,20 +170,4 @@ export const useProjectSessionSelection = (args: Args): { currentSessionDirector
    });
  }, [activeProjectId, currentSessionId, projectSessionMeta, setActiveSessionByProject]);
  const currentSessionDirectory = React.useMemo(() => {
    if (!currentSessionId) {
      return null;
    }
    const metadataPath = worktreeMetadata.get(currentSessionId)?.path;
    if (metadataPath) {
      return normalizePath(metadataPath) ?? metadataPath;
    }
    const activeSession = sessions.find((session) => session.id === currentSessionId);
    if (!activeSession) {
      return null;
    }
    return normalizePath((activeSession as Session & { directory?: string | null }).directory ?? null);
  }, [currentSessionId, sessions, worktreeMetadata]);
  return { currentSessionDirectory };
 };
@@ -105,9 +105,9 @@ export const useSessionActions = (args: Args) => {
    args.setEditTitle(sessionTitle);
  }, [args]);
-  const handleSaveEdit = React.useCallback(async () => {
+  const handleSaveEdit = React.useCallback(async (titleOverride?: string) => {
    if (!args.editingId) return;
-    const trimmed = args.editTitle.trim();
+    const trimmed = (titleOverride ?? args.editTitle).trim();
    if (trimmed) {
      await args.updateSessionTitle(args.editingId, trimmed);
    }
@@ -0,0 +1,237 @@
 import React from 'react';
 import { toast } from '@/components/ui';
 import { useI18n } from '@/lib/i18n';
 import { useSessionMultiSelectStore } from '@/stores/useSessionMultiSelectStore';
 import type { SessionFolder } from '@/stores/useSessionFoldersStore';
 type Args = {
  isInlineEditing: boolean;
  showDeletionDialog: boolean;
  foldersMap: Record<string, SessionFolder[]>;
  addSessionsToFolder: (scopeKey: string, folderId: string, sessionIds: string[]) => void;
  removeSessionsFromFolders: (scopeKey: string, sessionIds: string[]) => void;
  createFolderAndStartRename: (scopeKey: string, parentId?: string | null) => { id: string } | null;
  archiveSessions: (ids: string[]) => Promise<{ archivedIds: string[]; failedIds: string[] }>;
  deleteSessions: (ids: string[]) => Promise<{ deletedIds: string[]; failedIds: string[] }>;
  setBulkDeleteConfirm: React.Dispatch<React.SetStateAction<{
    sessionCount: number;
    archivedBucket: boolean;
  } | null>>;
 };
 /**
 * Bulk-action logic for the sidebar. The hot-path concern is that this
 * hook subscribes to `useSessionMultiSelectStore` — which can fire on
 * every selection toggle and on every setRange/toggleSelected call —
 * but the rest of the Sidebar tree only needs the boolean
 * `selectionModeEnabled` flag to decide whether to render the
 * selection chrome.
 *
 * To keep that subscription narrow, the heavy work (folders lookup,
 * DOM-attribute scanning for the active/archived scope, etc.) is
 * deferred behind a `selectedIds.size > 0` check inside the hook
 * itself, so toggling selection mode on/off does not force the
 * downstream useMemo chain to re-evaluate when no rows are selected.
 */
 export const useSidebarBulkActions = (args: Args) => {
  const { t } = useI18n();
  const {
    isInlineEditing,
    showDeletionDialog,
    foldersMap,
    addSessionsToFolder,
    removeSessionsFromFolders,
    createFolderAndStartRename,
    archiveSessions,
    deleteSessions,
    setBulkDeleteConfirm,
  } = args;
  const selectionModeEnabled = useSessionMultiSelectStore((state) => state.enabled);
  const selectedIdsSize = useSessionMultiSelectStore((state) => state.selectedIds.size);
  const hasSelection = selectedIdsSize > 0;
  const selectedIds = useSessionMultiSelectStore((state) => state.selectedIds);
  const selectionScopeKey = useSessionMultiSelectStore((state) => state.scopeKey);
  const handleToggleSelectionMode = React.useCallback(() => {
    useSessionMultiSelectStore.getState().toggleMode();
  }, []);
  const handleExitSelectionMode = React.useCallback(() => {
    useSessionMultiSelectStore.getState().disable();
  }, []);
  // All of the below short-circuit on `hasSelection` so the DOM-scanning
  // and folder-lookup work only runs when there's something to act on.
  const bulkScopeIsArchived = React.useMemo(() => {
    if (!hasSelection) return false;
    if (typeof document === 'undefined') return false;
    let sawActive = false;
    let sawArchived = false;
    for (const id of selectedIds) {
      const rows = document.querySelectorAll<HTMLElement>(`[data-session-row="${CSS.escape(id)}"]`);
      for (const row of rows) {
        if (row.getAttribute('data-session-archived') === '1') sawArchived = true;
        else sawActive = true;
      }
    }
    return sawArchived && !sawActive;
  }, [hasSelection, selectedIds]);
  const derivedSelectionScope = React.useMemo(() => {
    if (selectionScopeKey) return selectionScopeKey;
    if (!hasSelection) return null;
    if (typeof document === 'undefined') return null;
    for (const id of selectedIds) {
      const row = document.querySelector<HTMLElement>(`[data-session-row="${CSS.escape(id)}"]`);
      const scope = row?.getAttribute('data-session-scope');
      if (scope && scope.length > 0) return scope;
    }
    return null;
  }, [hasSelection, selectedIds, selectionScopeKey]);
  const bulkScopeFolders = React.useMemo(() => {
    if (!derivedSelectionScope) return [];
    return foldersMap[derivedSelectionScope] ?? [];
  }, [foldersMap, derivedSelectionScope]);
  const bulkCanRemoveFromFolder = React.useMemo(() => {
    if (!derivedSelectionScope || !hasSelection) return false;
    const scopeFolders = foldersMap[derivedSelectionScope] ?? [];
    for (const folder of scopeFolders) {
      for (const id of folder.sessionIds) {
        if (selectedIds.has(id)) return true;
      }
    }
    return false;
  }, [foldersMap, derivedSelectionScope, hasSelection, selectedIds]);
  const handleBulkMoveToFolder = React.useCallback((folderId: string) => {
    if (!derivedSelectionScope || !hasSelection) return;
    addSessionsToFolder(derivedSelectionScope, folderId, Array.from(selectedIds));
  }, [addSessionsToFolder, selectedIds, derivedSelectionScope, hasSelection]);
  const handleBulkCreateFolderAndMove = React.useCallback(() => {
    if (!derivedSelectionScope || !hasSelection) return;
    const newFolder = createFolderAndStartRename(derivedSelectionScope);
    if (!newFolder) return;
    addSessionsToFolder(derivedSelectionScope, newFolder.id, Array.from(selectedIds));
  }, [addSessionsToFolder, createFolderAndStartRename, selectedIds, derivedSelectionScope, hasSelection]);
  const handleBulkRemoveFromFolder = React.useCallback(() => {
    if (!derivedSelectionScope || !hasSelection) return;
    removeSessionsFromFolders(derivedSelectionScope, Array.from(selectedIds));
  }, [removeSessionsFromFolders, selectedIds, derivedSelectionScope, hasSelection]);
  const executeBulkDelete = React.useCallback(async () => {
    const ids = Array.from(selectedIds);
    if (ids.length === 0) return;
    if (bulkScopeIsArchived) {
      const { deletedIds, failedIds } = await deleteSessions(ids);
      if (deletedIds.length > 0) {
        toast.success(deletedIds.length === 1
          ? t('sessions.sidebar.bulkActions.deletedSingle', { count: deletedIds.length })
          : t('sessions.sidebar.bulkActions.deletedPlural', { count: deletedIds.length }));
      }
      if (failedIds.length > 0) {
        toast.error(failedIds.length === 1
          ? t('sessions.sidebar.bulkActions.failedDeleteSingle', { count: failedIds.length })
          : t('sessions.sidebar.bulkActions.failedDeletePlural', { count: failedIds.length }));
      }
    } else {
      const { archivedIds, failedIds } = await archiveSessions(ids);
      if (archivedIds.length > 0) {
        toast.success(archivedIds.length === 1
          ? t('sessions.sidebar.bulkActions.archivedSingle', { count: archivedIds.length })
          : t('sessions.sidebar.bulkActions.archivedPlural', { count: archivedIds.length }));
      }
      if (failedIds.length > 0) {
        toast.error(failedIds.length === 1
          ? t('sessions.sidebar.bulkActions.failedArchiveSingle', { count: failedIds.length })
          : t('sessions.sidebar.bulkActions.failedArchivePlural', { count: failedIds.length }));
      }
    }
    useSessionMultiSelectStore.getState().clear();
  }, [archiveSessions, bulkScopeIsArchived, deleteSessions, selectedIds, t]);
  const handleBulkDelete = React.useCallback(() => {
    if (!hasSelection) return;
    const count = selectedIds.size;
    if (!showDeletionDialog) {
      void executeBulkDelete();
      return;
    }
    setBulkDeleteConfirm({ sessionCount: count, archivedBucket: bulkScopeIsArchived });
  }, [bulkScopeIsArchived, executeBulkDelete, selectedIds, showDeletionDialog, setBulkDeleteConfirm, hasSelection]);
  const confirmBulkDelete = React.useCallback(async () => {
    setBulkDeleteConfirm(null);
    await executeBulkDelete();
    // setBulkDeleteConfirm is a stable React state setter; intentionally
    // omitted from deps to avoid forcing the keyboard-listener effect
    // below to re-subscribe on every render.
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [executeBulkDelete]);
  React.useEffect(() => {
    if (!selectionModeEnabled) return;
    const isMac = typeof navigator !== 'undefined' && /Macintosh|Mac OS X/.test(navigator.userAgent || '');
    const listener = (event: KeyboardEvent) => {
      if (isInlineEditing) return;
      const target = event.target as HTMLElement | null;
      if (target && (target.tagName === 'INPUT' || target.tagName === 'TEXTAREA' || target.isContentEditable)) {
        return;
      }
      const modifier = isMac ? event.metaKey : event.ctrlKey;
      if (event.key === 'Escape') {
        event.preventDefault();
        useSessionMultiSelectStore.getState().disable();
        return;
      }
      if (modifier && event.key === 'Backspace') {
        event.preventDefault();
        handleBulkDelete();
        return;
      }
      if (modifier && (event.key === 'a' || event.key === 'A')) {
        const rows = typeof document !== 'undefined'
          ? Array.from(document.querySelectorAll<HTMLElement>('[data-session-row]'))
          : [];
        if (rows.length === 0) return;
        event.preventDefault();
        const currentScope = useSessionMultiSelectStore.getState().scopeKey;
        const targetScope = currentScope
          ?? rows[0]?.getAttribute('data-session-scope')
          ?? null;
        const scopeFilter = (el: HTMLElement): boolean => {
          if (!targetScope) return true;
          return el.getAttribute('data-session-scope') === targetScope;
        };
        const ids = rows
          .filter(scopeFilter)
          .map((el) => el.getAttribute('data-session-row'))
          .filter((id): id is string => typeof id === 'string' && id.length > 0);
        if (ids.length === 0) return;
        useSessionMultiSelectStore.getState().replaceAll(ids, targetScope || null);
      }
    };
    window.addEventListener('keydown', listener);
    return () => window.removeEventListener('keydown', listener);
  }, [handleBulkDelete, isInlineEditing, selectionModeEnabled]);
  return {
    selectionModeEnabled,
    hasSelection,
    selectedIdsSize,
    bulkScopeIsArchived,
    derivedSelectionScope,
    bulkScopeFolders,
    bulkCanRemoveFromFolder,
    handleToggleSelectionMode,
    handleExitSelectionMode,
    handleBulkMoveToFolder,
    handleBulkCreateFolderAndMove,
    handleBulkRemoveFromFolder,
    handleBulkDelete,
    confirmBulkDelete,
  };
 };
@@ -0,0 +1,120 @@
 import type { SessionNode } from './types';
 /**
 * Per-row render extras precomputed once per group render and threaded down to
 * each `SessionNodeItem`. Hoisting these out of the row `React.memo` comparator
 * turns an O(rows × subtree-depth) walk into per-row `Set.has`/string compares.
 *
 * The child variant intentionally omits `childRenderExtrasFor` — the resolver is
 * shared from the group and re-passed, so it does not need to recurse through
 * each child's extras object.
 */
 export type SessionNodeChildRenderExtras = {
  subtreeContainsActive: Set<string>;
  subtreeContainsEditing: Set<string>;
  menuOpenSessionId: string | null;
  nodeStructureKey: string;
 };
 export type SessionNodeRenderExtras<TNode = SessionNode> = SessionNodeChildRenderExtras & {
  childRenderExtrasFor?: (child: TNode) => SessionNodeChildRenderExtras;
 };
 /**
 * Walk `nodes` and add `node.session.id` to `result` for every node
 * whose subtree contains `targetId`. This is used to precompute, once
 * per SessionGroupSection render, which rows need to update when
 * `currentSessionId` or `editingId` changes. With M visible rows, this
 * turns an O(M × subtree-depth) walk inside `SessionNodeItem.areEqual`
 * into a single O(M) `Set.has` per row.
 */
 export const collectSubtreeContainingId = (
  nodes: SessionNode[],
  targetId: string | null,
  result: Set<string>,
 ): void => {
  if (!targetId) return;
  const visit = (node: SessionNode): boolean => {
    let containsTarget = node.session.id === targetId;
    for (const child of node.children) {
      containsTarget = visit(child) || containsTarget;
    }
    if (containsTarget) {
      result.add(node.session.id);
    }
    return containsTarget;
  };
  for (const node of nodes) {
    visit(node);
  }
 };
 export const nodeContainsSessionId = (node: SessionNode, sessionId: string | null): boolean => {
  if (!sessionId) {
    return false;
  }
  if (node.session.id === sessionId) {
    return true;
  }
  for (const child of node.children) {
    if (nodeContainsSessionId(child, sessionId)) {
      return true;
    }
  }
  return false;
 };
 /**
 * Build a structural key for `node` that encodes the IDs of all
 * descendants. Used by `SessionNodeItem.areEqual` so a reference-only
 * rebuild of the tree (which happens on every `buildGroupedSessions`
 * pass) can be detected with a single string compare instead of a
 * recursive walk per row.
 */
 export const computeNodeStructureKey = (node: SessionNode): string => {
  if (node.children.length === 0) {
    return '';
  }
  const childKeys = node.children.map((child) => {
    if (child.children.length === 0) {
      return child.session.id;
    }
    return `${child.session.id}:${computeNodeStructureKey(child)}`;
  });
  return childKeys.join('|');
 };
 /**
 * Resolve the session id whose sidebar menu is open, or null if no
 * menu is open. Only one row can have its menu open at a time.
 */
 export const resolveMenuOpenSessionId = (
  nodes: SessionNode[],
  menuKey: string | null,
  renderContext: 'project' | 'recent',
  archivedBucket: boolean,
 ): string | null => {
  if (!menuKey) return null;
  const bucketTag = archivedBucket ? 'archived' : 'active';
  let result: string | null = null;
  const visit = (node: SessionNode): boolean => {
    const nodeMenuKey = `${renderContext}:${bucketTag}:${node.session.id}`;
    if (nodeMenuKey === menuKey) {
      result = node.session.id;
      return true;
    }
    for (const child of node.children) {
      if (visit(child)) return true;
    }
    return false;
  };
  nodes.forEach((node) => visit(node));
  return result;
 };
@@ -140,10 +140,11 @@ export const ScrollShadow = React.forwardRef<HTMLElement, ScrollShadowProps>(
      el.addEventListener("scroll", handleScroll, { passive: true });
      resizeObserver?.observe(el);
      // checkOverflow mutates our data-scroll attributes; observing attributes
      // would make the component trigger its own observer indefinitely.
      mutationObserver?.observe(el, {
        childList: true,
        subtree: true,
        attributes: true,
        characterData: true,
      });
@@ -3,6 +3,12 @@
@import "./styles/design-system.css";
@import "./styles/typography.css";
@import "./styles/mobile.css";
 /* Load KaTeX styles eagerly with the main bundle. Importing them inside the
   lazy MarkdownRendererImpl chunk meant a stylesheet was injected late on the
   first markdown render of a session; that late injection triggered a style
   recalc during which the layered `.chat-message-column` width clamp briefly
   lost, flashing message text to full width before it snapped back. */
@import "katex/dist/katex.min.css";
@source "./**/*.{ts,tsx,css}";
 /* KaTeX theme overrides for light/dark mode */
@@ -2,6 +2,8 @@ import { create } from 'zustand';
 import type { OpencodeClient, Session } from '@opencode-ai/sdk/v2';
 import { opencodeClient } from '@/lib/opencode/client';
 import { listGlobalSessionPages } from '@/stores/globalSessions';
 import { getReviewTransferDirection, type ReviewTransferDirection } from '@/lib/reviewFlow';
 import { getOriginalSessionID, getReviewSessionID } from '@/lib/sessionReviewMetadata';
 type GlobalSessionsStatus = 'idle' | 'loading' | 'ready' | 'error';
@@ -14,6 +16,7 @@ type GlobalSessionsState = {
  activeSessions: Session[];
  archivedSessions: Session[];
  sessionsByDirectory: Map<string, Session[]>;
  reviewTransferBySessionId: Map<string, ReviewTransferDirection>;
  hasLoaded: boolean;
  status: GlobalSessionsStatus;
  loadSessions: (fallbackActive?: Session[]) => Promise<LoadResult>;
@@ -297,11 +300,15 @@ const applySnapshot = (
  const nextSessionsByDirectory = nextActiveSessions === state.activeSessions
    ? state.sessionsByDirectory
    : buildSessionsByDirectory(nextActiveSessions);
  const nextReviewTransferMap = nextActiveSessions === state.activeSessions
    ? state.reviewTransferBySessionId
    : buildReviewTransferMap(nextActiveSessions);
  if (
    nextActiveSessions === state.activeSessions
    && nextArchivedSessions === state.archivedSessions
    && nextSessionsByDirectory === state.sessionsByDirectory
    && nextReviewTransferMap === state.reviewTransferBySessionId
    && state.hasLoaded
    && state.status === status
  ) {
@@ -312,15 +319,32 @@ const applySnapshot = (
    activeSessions: nextActiveSessions,
    archivedSessions: nextArchivedSessions,
    sessionsByDirectory: nextSessionsByDirectory,
    reviewTransferBySessionId: nextReviewTransferMap,
    hasLoaded: true,
    status,
  };
 };
 const buildReviewTransferMap = (sessions: Session[]): Map<string, ReviewTransferDirection> => {
  const next = new Map<string, ReviewTransferDirection>()
  const activeIds = new Set(sessions.map((s) => s.id))
  for (const session of sessions) {
    const direction = getReviewTransferDirection(session)
    if (!direction) continue
    const targetSessionId = direction === 'review-to-original'
      ? getOriginalSessionID(session)
      : getReviewSessionID(session)
    if (!targetSessionId || !activeIds.has(targetSessionId)) continue
    next.set(session.id, direction)
  }
  return next
 }
 export const useGlobalSessionsStore = create<GlobalSessionsState>((set, get) => ({
  activeSessions: [],
  archivedSessions: [],
  sessionsByDirectory: new Map(),
  reviewTransferBySessionId: new Map(),
  hasLoaded: false,
  status: 'idle',
@@ -424,6 +448,9 @@ export const useGlobalSessionsStore = create<GlobalSessionsState>((set, get) =>
        activeSessions: nextActiveSessions,
        archivedSessions: nextArchivedSessions,
        sessionsByDirectory: nextSessionsByDirectory,
        reviewTransferBySessionId: nextActiveSessions === state.activeSessions
          ? state.reviewTransferBySessionId
          : buildReviewTransferMap(nextActiveSessions),
      };
    });
@@ -458,6 +485,9 @@ export const useGlobalSessionsStore = create<GlobalSessionsState>((set, get) =>
        sessionsByDirectory: nextActiveSessions === state.activeSessions
          ? state.sessionsByDirectory
          : buildSessionsByDirectory(nextActiveSessions),
        reviewTransferBySessionId: nextActiveSessions === state.activeSessions
          ? state.reviewTransferBySessionId
          : buildReviewTransferMap(nextActiveSessions),
      };
    });
  },
@@ -483,6 +513,7 @@ export const useGlobalSessionsStore = create<GlobalSessionsState>((set, get) =>
        activeSessions: nextActiveSessions,
        archivedSessions: nextArchivedSessions,
        sessionsByDirectory: buildSessionsByDirectory(nextActiveSessions),
        reviewTransferBySessionId: buildReviewTransferMap(nextActiveSessions),
      };
    });
  },
@@ -520,6 +551,7 @@ export const useGlobalSessionsStore = create<GlobalSessionsState>((set, get) =>
        activeSessions: nextActiveSessions,
        archivedSessions: [...movedSessions, ...remainingArchivedSessions],
        sessionsByDirectory: buildSessionsByDirectory(nextActiveSessions),
        reviewTransferBySessionId: buildReviewTransferMap(nextActiveSessions),
      };
    });
  },
@@ -158,3 +158,18 @@
    font-weight: var(--markdown-h4-font-weight);
  }
 }
 /* Chat message column width — intentionally UNLAYERED so it always wins the
   cascade. The same rule inside `@layer components` above is correct in steady
   state, but a layered rule can be momentarily out-ranked during a heavy style
   recalc (e.g. a large session's virtualized list re-laying-out when the
   background history prepend lands, or a late-loaded CSS chunk re-establishing
   layer order). That dropped the clamp for a frame and flashed message text to
   full width. An unlayered duplicate of just the width keeps it robust. */
 .chat-message-column {
  width: min(100%, 48rem);
 }
 .wide-chat-layout .chat-message-column {
  width: min(100%, 64rem);
 }
@@ -0,0 +1,54 @@
 import { describe, expect, test } from "bun:test"
 import type { Session } from "@opencode-ai/sdk/v2"
 import {
  areRequestArraysReferentiallyEqual,
  collectScopedBlockingRequests,
 } from "./scoped-blocking-requests"
 const session = (id: string, parentID?: string): Session => ({ id, parentID }) as Session
 describe("scoped blocking requests", () => {
  test("collects requests for the current session subtree", () => {
    const rootRequest = { id: "perm_root" }
    const childRequest = { id: "perm_child" }
    const grandchildRequest = { id: "perm_grandchild" }
    const siblingRequest = { id: "perm_sibling" }
    const empty: Array<typeof rootRequest> = []
    const result = collectScopedBlockingRequests(
      [
        session("ses_root"),
        session("ses_child", "ses_root"),
        session("ses_grandchild", "ses_child"),
        session("ses_sibling"),
      ],
      {
        ses_root: [rootRequest],
        ses_child: [childRequest],
        ses_grandchild: [grandchildRequest],
        ses_sibling: [siblingRequest],
      },
      "ses_root",
      empty,
    )
    expect(result).toEqual([rootRequest, childRequest, grandchildRequest])
  })
  test("returns the provided empty array when no scoped requests exist", () => {
    const empty: Array<{ id: string }> = []
    expect(collectScopedBlockingRequests([session("ses_root")], {}, "ses_root", empty)).toBe(empty)
    expect(collectScopedBlockingRequests([session("ses_root")], {}, null, empty)).toBe(empty)
  })
  test("compares request arrays by item identity", () => {
    const first = { id: "perm_1" }
    const second = { id: "perm_2" }
    expect(areRequestArraysReferentiallyEqual([first, second], [first, second])).toBe(true)
    expect(areRequestArraysReferentiallyEqual([first, second], [second, first])).toBe(false)
    expect(areRequestArraysReferentiallyEqual([first], [{ id: "perm_1" }])).toBe(false)
  })
 })
@@ -0,0 +1,61 @@
 import type { Session } from "@opencode-ai/sdk/v2"
 type BlockingRequest = { id: string }
 export const computeSubtreeIds = (sessions: Session[], rootId: string): Set<string> => {
  const childrenByParent = new Map<string, string[]>()
  for (const session of sessions) {
    if (!session.parentID) continue
    const list = childrenByParent.get(session.parentID) ?? []
    list.push(session.id)
    childrenByParent.set(session.parentID, list)
  }
  const ids = new Set<string>([rootId])
  const queue = [rootId]
  for (const id of queue) {
    const children = childrenByParent.get(id)
    if (!children) continue
    for (const childId of children) {
      if (ids.has(childId)) continue
      ids.add(childId)
      queue.push(childId)
    }
  }
  return ids
 }
 export const areRequestArraysReferentiallyEqual = <T extends BlockingRequest>(left: T[], right: T[]): boolean => {
  if (left === right) return true
  if (left.length !== right.length) return false
  for (let index = 0; index < left.length; index += 1) {
    if (left[index] !== right[index]) return false
  }
  return true
 }
 export const collectScopedBlockingRequests = <T extends BlockingRequest>(
  sessions: Session[],
  requestsBySession: Record<string, T[] | undefined>,
  sessionID: string | null,
  empty: T[],
 ): T[] => {
  if (!sessionID) return empty
  const scopedIds = computeSubtreeIds(sessions, sessionID)
  if (scopedIds.size === 0) return empty
  const seen = new Set<string>()
  const result: T[] = []
  for (const id of scopedIds) {
    const entries = requestsBySession[id]
    if (!entries) continue
    for (const entry of entries) {
      if (seen.has(entry.id)) continue
      seen.add(entry.id)
      result.push(entry)
    }
  }
  return result.length === 0 ? empty : result
 }
@@ -13,7 +13,10 @@ import { mergeSessionDirectoryMetadata, useGlobalSessionsStore } from "@/stores/
 import { useConfigStore } from "@/stores/useConfigStore"
 import { registerSessionDirectory } from "./sync-refs"
 import { isSyntheticPart } from "@/lib/messages/synthetic"
-import { materializeSessionSnapshots } from "./materialization"
+import { getSessionMaterializationStatus, materializeSessionSnapshots } from "./materialization"
 import { retry } from "./retry"
 import { isVSCodeRuntime } from "@/lib/desktop"
 import { isMobileSurfaceRuntime } from "@/lib/runtimeSurface"
 import { stripMessageDiffSnapshots, stripSessionDiffSnapshots } from "./sanitize"
 import { sessionEvents } from "@/lib/sessionEvents"
 import {
@@ -24,7 +27,7 @@ import {
  type SessionMetadataRecord,
 } from "@/lib/sessionReviewMetadata"
-const MESSAGE_REFETCH_LIMIT = 200
+const MESSAGE_REFETCH_LIMIT = 100
 const MESSAGE_REFETCH_SKIP_PARTS = new Set(["patch", "step-start", "step-finish"])
 const UNREVERT_REFETCH_ATTEMPTS = 3
 const UNREVERT_REFETCH_RETRY_MS = 150
@@ -1037,3 +1040,71 @@ export async function forkFromMessage(sessionId: string, messageId: string): Pro
  // Clear existing attachments and restore file parts from the forked message.
  restoreFilePartsToInput(fileParts)
 }
 // ---------------------------------------------------------------------------
 // Imperative fetch path — starts message loading on the same tick as
 // setCurrentSession, before the React commit cycle fires useEffect.
 // ---------------------------------------------------------------------------
 const FETCH_MESSAGES_LOADING = new Set<string>()
 const DESKTOP_INITIAL_PAGE_SIZE = 50
 const CONSTRAINED_INITIAL_PAGE_SIZE = 30
 const getFetchPageSize = () => {
  if (isVSCodeRuntime() || isMobileSurfaceRuntime()) return CONSTRAINED_INITIAL_PAGE_SIZE
  return DESKTOP_INITIAL_PAGE_SIZE
 }
 export async function fetchMessagesForSession(sessionID: string, directory?: string | null): Promise<void> {
  const resolvedDir = directory ?? dir()
  if (!resolvedDir) return
  const s = sdk()
  const store = directory
    ? dirStoreForDirectory(directory)
    : dirStore()
  if (getSessionMaterializationStatus(store.getState(), sessionID).renderable) return
  const loadingKey = `${resolvedDir}:${sessionID}`
  if (FETCH_MESSAGES_LOADING.has(loadingKey)) return
  FETCH_MESSAGES_LOADING.add(loadingKey)
  try {
    const result = await retry(async () => {
      const response = await s.session.messages({
        sessionID,
        directory: resolvedDir,
        limit: getFetchPageSize(),
      })
      return response
    })
    const records = (assertSdkSuccess(result, "session.messages") ?? [])
      .filter((record: { info?: { id?: string } }) => !!record?.info?.id)
    if (records.length === 0) return
    // Staleness guard: a rapid session switch may have moved the user off this
    // session while the fetch was in flight. Skip the write so a slow fetch
    // can't repopulate (and un-evict) a session already navigated away from.
    if (useSessionUIStore.getState().currentSessionId !== sessionID) return
    store.setState((state) => {
      const materialized = materializeSessionSnapshots(
        state,
        sessionID,
        records.map((record: { info: Message; parts?: Part[] }) => ({
          info: stripMessageDiffSnapshots(record.info),
          parts: record.parts ?? [],
        })),
        { skipPartTypes: MESSAGE_REFETCH_SKIP_PARTS },
      )
      return { message: materialized.message, part: materialized.part }
    })
  } catch {
    // Transient failure — the reactive path in ChatContainer will retry
  } finally {
    FETCH_MESSAGES_LOADING.delete(loadingKey)
  }
 }
@@ -0,0 +1,68 @@
 import { describe, expect, test } from 'bun:test';
 import type { Message, Part } from '@opencode-ai/sdk/v2/client';
 import { buildSessionMessageRecordsSnapshot } from './sync-context';
 import { INITIAL_STATE, type State } from './types';
 const message = (id: string, role: 'user' | 'assistant', parentID?: string): Message => ({
  id,
  role,
  sessionID: 'ses_1',
  ...(parentID ? { parentID } : {}),
  time: { created: 1 },
 } as Message);
 const textPart = (id: string, text: string): Part => ({
  id,
  type: 'text',
  text,
 } as Part);
 const state = (partial: Partial<State>): State => ({
  ...INITIAL_STATE,
  ...partial,
 });
 describe('buildSessionMessageRecordsSnapshot', () => {
  test('only suspends part updates for the active streaming message', () => {
    const user = message('user_1', 'user');
    const assistant1 = message('assistant_1', 'assistant', 'user_1');
    const assistant2 = message('assistant_2', 'assistant', 'user_1');
    const messages = [user, assistant1, assistant2];
    const assistant1InitialParts = [textPart('assistant_1_initial', 'initial')];
    const assistant2InitialParts = [textPart('assistant_2_initial', 'initial')];
    const previous = buildSessionMessageRecordsSnapshot(
      state({
        message: { ses_1: messages },
        part: {
          assistant_1: assistant1InitialParts,
          assistant_2: assistant2InitialParts,
        },
      }),
      'ses_1',
      undefined,
      true,
      'assistant_1',
    );
    const assistant1FinalParts = [textPart('assistant_1_final', 'final')];
    const assistant2LiveParts = [textPart('assistant_2_live', 'live')];
    const next = buildSessionMessageRecordsSnapshot(
      state({
        message: { ses_1: messages },
        part: {
          assistant_1: assistant1FinalParts,
          assistant_2: assistant2LiveParts,
        },
      }),
      'ses_1',
      previous,
      true,
      'assistant_2',
    );
    expect(next.byId.get('assistant_1')?.parts).toBe(assistant1FinalParts);
    expect(next.byId.get('assistant_2')?.parts).toBe(assistant2InitialParts);
  });
 });
@@ -51,6 +51,7 @@ import {
  revertToMessage as revertToMessageAction,
  unrevertSession as unrevertSessionAction,
  forkFromMessage as forkFromMessageAction,
  fetchMessagesForSession,
 } from "./session-actions"
 import { useInputStore, type SyntheticContextPart } from "./input-store"
 import { useSelectionStore } from "./selection-store"
@@ -497,6 +498,13 @@ export const useSessionUIStore = create<SessionUIState>()((set, get) => ({
    set({ currentSessionId: id, currentSessionDirectory: id ? resolvedDir ?? null : null })
    writeRuntimeSessionMemory(key, { sessionId: id, directory: resolvedDir ?? null })
    // Kick off the message fetch on the same tick, before React commits the
    // state change and fires ChatContainer.useEffect. The fetch is
    // fire-and-forget — any transient failure gets retried by the reactive path.
    if (id) {
      void fetchMessagesForSession(id, resolvedDir)
    }
    try {
      if (resolvedDir && directoryState.currentDirectory !== resolvedDir) {
        directoryState.setDirectory(resolvedDir, { showOverlay: false })
@@ -23,7 +23,7 @@ import { bootstrapGlobal, bootstrapDirectory } from "./bootstrap"
 import { retry } from "./retry"
 import { updateStreamingState } from "./streaming"
 import { setActionRefs } from "./session-actions"
-import { setSyncRefs } from "./sync-refs"
+import { setSyncRefs, getAllSyncSessions } from "./sync-refs"
 import { stripMessageDiffSnapshots, stripSessionDiffSnapshots } from "./sanitize"
 import { syncDebug } from "./debug"
 import { getReconnectCandidateSessionIds } from "./reconnect-recovery"
@@ -47,6 +47,8 @@ import { getRegisteredRuntimeAPIs } from "@/contexts/runtimeAPIRegistry"
 import { setSessionPrefetch } from "./session-prefetch-cache"
 import { listGlobalSessionPages } from "@/stores/globalSessions"
 import { useGlobalSessionsStore } from "@/stores/useGlobalSessionsStore"
 import { areRequestArraysReferentiallyEqual, collectScopedBlockingRequests } from "./scoped-blocking-requests"
 import { EMPTY_USER_MESSAGE_HISTORY_SNAPSHOT, buildUserMessageHistorySnapshot, type UserMessageHistorySnapshot } from "./user-message-history"
 // ---------------------------------------------------------------------------
 // Context
@@ -260,6 +262,7 @@ async function materializeSessionFromServer(
  directory: string,
  sessionID: string,
  store: StoreApi<DirectoryStore>,
  options?: { isStale?: () => boolean },
 ) {
  const scopedClient = opencodeClient.getScopedSdkClient(directory)
  const result = await retry(async () => {
@@ -278,6 +281,8 @@ async function materializeSessionFromServer(
    complete: !cursor,
  })
  if (options?.isStale?.()) return
  store.setState((state: DirectoryStore) => {
    const materialized = materializeSessionSnapshots(
      state,
@@ -326,12 +331,12 @@ type UiNotificationPayload = {
  body?: unknown
  tag?: unknown
  kind?: unknown
-  sessionId?: unknown
+  sessionId?: unknown
-  directory?: unknown
+  directory?: unknown
-  requireHidden?: unknown
+  requireHidden?: unknown
-  desktopNotificationDelivered?: unknown
+  desktopNotificationDelivered?: unknown
-  desktopStdoutActive?: unknown
+  desktopStdoutActive?: unknown
-}
+}
 const asOptionalString = (value: unknown): string | undefined => {
  if (typeof value !== "string") return undefined
@@ -350,9 +355,9 @@ const handleUiNotificationEvent = (payload: Event, fallbackDirectory: string): b
  }
  const notification = properties as UiNotificationPayload
-  if ((notification.desktopNotificationDelivered === true || notification.desktopStdoutActive === true) && getRuntimeKey() === "local") {
+  if ((notification.desktopNotificationDelivered === true || notification.desktopStdoutActive === true) && getRuntimeKey() === "local") {
-    return true
+    return true
-  }
+  }
  const notifications = getRegisteredRuntimeAPIs()?.notifications
  if (!notifications?.notifyAgentCompletion) {
@@ -1657,10 +1662,10 @@ export function SyncProvider(props: {
                ingestDirectoryStateIntoRoutingIndex(routingIndex, directory, store.getState())
              }
            },
-            global: {
+            global: {
-              config: globalState.config,
+              config: globalState.config,
-              projects: globalState.projects,
+              projects: globalState.projects,
-            },
+            },
            loadSessions: (dir) => retry(async () => {
              const rootSessions = (await listGlobalSessionPages(props.sdk, {
                directory: dir,
@@ -1751,11 +1756,11 @@ export function SyncProvider(props: {
    const generation = ++globalBootstrapGeneration
    bootingRoot = true
    const globalActions = useGlobalSyncStore.getState().actions
-    bootstrapGlobal(props.sdk, (patch) => {
+    bootstrapGlobal(props.sdk, (patch) => {
-      if (globalBootstrapGeneration === generation) {
+      if (globalBootstrapGeneration === generation) {
-        globalActions.set(patch)
+        globalActions.set(patch)
-      }
+      }
-    })
+    })
      .then(() => {
        if (globalBootstrapGeneration === generation) {
          bootedAt = Date.now()
@@ -1771,7 +1776,7 @@ export function SyncProvider(props: {
        bootingRoot = false
      }
    }
-  }, [props.sdk])
+  }, [props.sdk])
  // Event pipeline — created once per mount. No class, no start/stop.
  // Abort controller owned by the pipeline closure. Cleanup aborts + flushes.
@@ -2177,6 +2182,77 @@ export function useSessions(directory?: string) {
  )
 }
 const selectPermissionRequestsBySession = (state: State) => state.permission
 const selectQuestionRequestsBySession = (state: State) => state.question
 type ScopedBlockingRequestCache<T extends { id: string }> = {
  sessionID: string | null
  sessions: Session[] | null
  requestsBySession: Record<string, T[] | undefined> | null
  result: T[]
 }
 function useScopedBlockingRequests<T extends { id: string }>(
  sessionID: string | null,
  directory: string | undefined,
  selectRequestsBySession: (state: State) => Record<string, T[] | undefined>,
  empty: T[],
 ): T[] {
  const cacheRef = useRef<ScopedBlockingRequestCache<T>>({
    sessionID: null,
    sessions: null,
    requestsBySession: null,
    result: empty,
  })
  return useDirectorySync(
    useCallback((state: State) => {
      const requestsBySession = selectRequestsBySession(state)
      const cache = cacheRef.current
      if (
        cache.sessionID === sessionID
        && cache.sessions === state.session
        && cache.requestsBySession === requestsBySession
      ) {
        return cache.result
      }
      const next = collectScopedBlockingRequests(state.session, requestsBySession, sessionID, empty)
      const result = areRequestArraysReferentiallyEqual(cache.result, next) ? cache.result : next
      cacheRef.current = {
        sessionID,
        sessions: state.session,
        requestsBySession,
        result,
      }
      return result
    }, [empty, selectRequestsBySession, sessionID]),
    directory,
  )
 }
 export function useScopedBlockingPermissions(sessionID: string | null, directory?: string): PermissionRequest[] {
  return useScopedBlockingRequests(sessionID, directory, selectPermissionRequestsBySession, EMPTY_PERMISSION_REQUESTS)
 }
 export function useScopedBlockingQuestions(sessionID: string | null, directory?: string): QuestionRequest[] {
  return useScopedBlockingRequests(sessionID, directory, selectQuestionRequestsBySession, EMPTY_QUESTION_REQUESTS)
 }
 export function useParentSession(sessionID: string | null, directory?: string): Session | null {
  return useDirectorySync(
    useCallback((state: State) => {
      if (!sessionID) return null
      const current = state.session.find((s) => s.id === sessionID)
      if (!current?.parentID) return null
      return state.session.find((s) => s.id === current.parentID)
        ?? getAllSyncSessions().find((s) => s.id === current.parentID)
        ?? null
    }, [sessionID]),
    directory,
  )
 }
 const getSidebarSessionSignature = (session: Session, stableUpdatedAt: number): string => {
  const directory = (session as Session & { directory?: string | null }).directory ?? ''
  const parentID = (session as Session & { parentID?: string | null }).parentID ?? ''
@@ -2348,14 +2424,6 @@ const getConcatenatedTextFromParts = (parts: Part[]): string => {
  return text
 }
 const getFirstTextFromParts = (parts: Part[]): string => {
  for (const part of parts) {
    const text = getPartText(part)
    if (text.length > 0) return text
  }
  return ""
 }
 type SessionMessageRecord = { info: Message; parts: Part[] }
 const EMPTY_SESSION_MESSAGE_RECORDS: SessionMessageRecord[] = []
@@ -2365,6 +2433,7 @@ type SessionMessageRecordsSnapshot = {
  visibleMessages: Message[]
  revertMessageID?: string
  suspendPartUpdates: boolean
  suspendedPartUpdatesMessageID?: string
  list: SessionMessageRecord[]
  byId: Map<string, SessionMessageRecord>
 }
@@ -2376,8 +2445,12 @@ const MOBILE_SESSION_MESSAGE_RECORDS_CACHE_MAX = 4
 const MOBILE_SESSION_MESSAGE_RECORDS_CACHE_MAX_MESSAGES = 30
 const sessionMessageRecordsCache = new WeakMap<StoreApi<DirectoryStore>, Map<string, SessionMessageRecordsSnapshot>>()
-const getSessionMessageRecordsCacheKey = (sessionID: string, suspendPartUpdates: boolean): string => (
+const getSessionMessageRecordsCacheKey = (
-  `${sessionID}\u0000${suspendPartUpdates ? 1 : 0}`
+  sessionID: string,
  suspendPartUpdates: boolean,
  suspendedPartUpdatesMessageID?: string,
 ): string => (
  `${sessionID}\u0000${suspendPartUpdates ? 1 : 0}\u0000${suspendedPartUpdatesMessageID ?? ""}`
 )
 const getSessionMessageRecordsCache = (store: StoreApi<DirectoryStore>): Map<string, SessionMessageRecordsSnapshot> => {
@@ -2393,10 +2466,11 @@ const readCachedSessionMessageRecordsSnapshot = (
  store: StoreApi<DirectoryStore>,
  sessionID: string,
  suspendPartUpdates: boolean,
  suspendedPartUpdatesMessageID?: string,
 ): SessionMessageRecordsSnapshot | undefined => {
  const cache = sessionMessageRecordsCache.get(store)
  if (!cache) return undefined
-  const key = getSessionMessageRecordsCacheKey(sessionID, suspendPartUpdates)
+  const key = getSessionMessageRecordsCacheKey(sessionID, suspendPartUpdates, suspendedPartUpdatesMessageID)
  const cached = cache.get(key)
  if (!cached) return undefined
  cache.delete(key)
@@ -2410,7 +2484,11 @@ const rememberSessionMessageRecordsSnapshot = (
 ): void => {
  if (!snapshot.sessionID) return
  const cache = getSessionMessageRecordsCache(store)
-  const key = getSessionMessageRecordsCacheKey(snapshot.sessionID, snapshot.suspendPartUpdates)
+  const key = getSessionMessageRecordsCacheKey(
    snapshot.sessionID,
    snapshot.suspendPartUpdates,
    snapshot.suspendedPartUpdatesMessageID,
  )
  const constrainedMaxMessages = isVSCodeRuntime()
    ? VSCODE_SESSION_MESSAGE_RECORDS_CACHE_MAX_MESSAGES
    : isMobileSurfaceRuntime()
@@ -2442,17 +2520,23 @@ export function dropCachedSessionMessageRecordsSnapshots(
  if (!cache) return
  for (const sessionID of sessionIDs) {
    if (!sessionID) continue
-    cache.delete(getSessionMessageRecordsCacheKey(sessionID, false))
+    const prefix = `${sessionID}\u0000`
-    cache.delete(getSessionMessageRecordsCacheKey(sessionID, true))
+    for (const key of [...cache.keys()]) {
      if (key.startsWith(prefix)) {
        cache.delete(key)
      }
    }
  }
 }
 const snapshotPartsMatchState = (snapshot: SessionMessageRecordsSnapshot, state: State): boolean => {
  if (snapshot.suspendPartUpdates) {
    return true
  }
  for (const record of snapshot.list) {
    if (snapshot.suspendPartUpdates) {
      const suspendedID = snapshot.suspendedPartUpdatesMessageID
      if (!suspendedID || record.info.id === suspendedID) {
        continue
      }
    }
    if ((state.part[record.info.id] ?? EMPTY_PARTS) !== record.parts) {
      return false
    }
@@ -2466,8 +2550,9 @@ const getReusableSessionMessageRecordsSnapshot = (
  state: State,
  sessionID: string,
  suspendPartUpdates: boolean,
  suspendedPartUpdatesMessageID?: string,
 ): SessionMessageRecordsSnapshot | undefined => {
-  const cached = readCachedSessionMessageRecordsSnapshot(store, sessionID, suspendPartUpdates)
+  const cached = readCachedSessionMessageRecordsSnapshot(store, sessionID, suspendPartUpdates, suspendedPartUpdatesMessageID)
  if (!cached) return undefined
  const sourceMessages = state.message[sessionID] ?? EMPTY_MESSAGES
  const session = state.session.find((candidate) => candidate.id === sessionID)
@@ -2476,6 +2561,7 @@ const getReusableSessionMessageRecordsSnapshot = (
    cached.sourceMessages === sourceMessages
    && cached.revertMessageID === revertMessageID
    && cached.suspendPartUpdates === suspendPartUpdates
    && cached.suspendedPartUpdatesMessageID === suspendedPartUpdatesMessageID
    && snapshotPartsMatchState(cached, state)
  ) {
    return cached
@@ -2516,12 +2602,16 @@ export function buildSessionMessageRecordsSnapshot(
  sessionID: string,
  previous?: SessionMessageRecordsSnapshot,
  suspendPartUpdates = false,
  suspendedPartUpdatesMessageID?: string,
 ): SessionMessageRecordsSnapshot {
  const { sourceMessages, visibleMessages, revertMessageID } = getVisibleMessagesForSession(state, sessionID, previous)
  const nextById = new Map<string, SessionMessageRecord>()
  const nextList = visibleMessages.map((message) => {
    const previousRecord = previous?.byId.get(message.id)
-    const parts = suspendPartUpdates && previousRecord
+    const shouldSuspendParts = suspendPartUpdates
      && previousRecord
      && (!suspendedPartUpdatesMessageID || message.id === suspendedPartUpdatesMessageID)
    const parts = shouldSuspendParts
      ? previousRecord.parts
      : (state.part[message.id] ?? EMPTY_PARTS)
@@ -2535,6 +2625,8 @@ export function buildSessionMessageRecordsSnapshot(
  const unchanged = Boolean(previous)
    && previous?.visibleMessages === visibleMessages
    && previous.suspendPartUpdates === suspendPartUpdates
    && previous.suspendedPartUpdatesMessageID === suspendedPartUpdatesMessageID
    && previous.list.length === nextList.length
    && previous.list.every((record, index) => record === nextList[index])
@@ -2548,6 +2640,7 @@ export function buildSessionMessageRecordsSnapshot(
    visibleMessages,
    revertMessageID,
    suspendPartUpdates,
    suspendedPartUpdatesMessageID,
    list: nextList,
    byId: nextById,
  }
@@ -2577,20 +2670,21 @@ export function useSessionTextMessages(sessionID: string, directory?: string): S
 }
 export function useUserMessageHistory(sessionID: string, directory?: string): string[] {
-  const records = useSessionMessageRecords(sessionID, directory)
+  const store = useDirectoryStore(directory)
-  const userMessages = useMemo(() => records.filter((record) => record.info.role === 'user'), [records])
+  const snapshotRef = useRef<UserMessageHistorySnapshot>(EMPTY_USER_MESSAGE_HISTORY_SNAPSHOT)
-  return useMemo(() => {
+  const getSnapshot = useCallback(() => {
-    const history: string[] = []
+    const next = buildUserMessageHistorySnapshot(store.getState(), sessionID, snapshotRef.current)
-    for (let index = userMessages.length - 1; index >= 0; index -= 1) {
+    snapshotRef.current = next
-      const message = userMessages[index]
+    return next.history
-      const text = getFirstTextFromParts(message.parts)
+  }, [sessionID, store])
-      if (text.length > 0) {
+
-        history.push(text)
+  const subscribe = useCallback((notify: () => void) => {
-      }
+    if (!sessionID) return () => undefined
-    }
+    return store.subscribe(notify)
-    return history
+  }, [sessionID, store])
-  }, [userMessages])
+
  return React.useSyncExternalStore(subscribe, getSnapshot, getSnapshot)
 }
 /**
@@ -2603,7 +2697,7 @@ export function useUserMessageHistory(sessionID: string, directory?: string): st
 export function useSessionMessageRecords(
  sessionID: string,
  directory?: string,
-  options?: { suspendPartUpdates?: boolean },
+  options?: { suspendPartUpdates?: boolean; suspendPartUpdatesForMessageId?: string | null },
 ) {
  const store = useDirectoryStore(directory)
  const snapshotRef = useRef<SessionMessageRecordsSnapshot>({
@@ -2612,6 +2706,7 @@ export function useSessionMessageRecords(
    visibleMessages: EMPTY_MESSAGES,
    revertMessageID: undefined,
    suspendPartUpdates: Boolean(options?.suspendPartUpdates),
    suspendedPartUpdatesMessageID: options?.suspendPartUpdatesForMessageId ?? undefined,
    list: [],
    byId: new Map(),
  })
@@ -2623,7 +2718,14 @@ export function useSessionMessageRecords(
    const state = store.getState()
    const suspendPartUpdates = Boolean(options?.suspendPartUpdates)
-    const reusableSnapshot = getReusableSessionMessageRecordsSnapshot(store, state, sessionID, suspendPartUpdates)
+    const suspendedPartUpdatesMessageID = options?.suspendPartUpdatesForMessageId ?? undefined
    const reusableSnapshot = getReusableSessionMessageRecordsSnapshot(
      store,
      state,
      sessionID,
      suspendPartUpdates,
      suspendedPartUpdatesMessageID,
    )
    if (reusableSnapshot) {
      snapshotRef.current = reusableSnapshot
      return reusableSnapshot.list
@@ -2631,18 +2733,19 @@ export function useSessionMessageRecords(
    const previousSnapshot = snapshotRef.current.sessionID === sessionID
      ? snapshotRef.current
-      : readCachedSessionMessageRecordsSnapshot(store, sessionID, suspendPartUpdates)
+      : readCachedSessionMessageRecordsSnapshot(store, sessionID, suspendPartUpdates, suspendedPartUpdatesMessageID)
    const nextSnapshot = buildSessionMessageRecordsSnapshot(
      state,
      sessionID,
      previousSnapshot,
      suspendPartUpdates,
      suspendedPartUpdatesMessageID,
    )
    snapshotRef.current = nextSnapshot
    rememberSessionMessageRecordsSnapshot(store, nextSnapshot)
    return nextSnapshot.list
-  }, [options?.suspendPartUpdates, sessionID, store])
+  }, [options?.suspendPartUpdates, options?.suspendPartUpdatesForMessageId, sessionID, store])
  const subscribe = useCallback((notify: () => void) => {
    if (!sessionID) return () => undefined
@@ -2671,6 +2774,7 @@ export function useEnsureSessionMessages(sessionID: string, directory?: string)
  const syncDirectory = useSyncDirectory()
  const resolvedDirectory = directory ?? syncDirectory
  const store = useDirectoryStore(resolvedDirectory)
  const requestGenerationRef = React.useRef(0)
  React.useEffect(() => {
    if (!sessionID) return
@@ -2685,11 +2789,14 @@ export function useEnsureSessionMessages(sessionID: string, directory?: string)
    // Already loading this session for this directory
    if (_ensureMessagesLoading.has(loadingKey)) return
    const generation = ++requestGenerationRef.current
    const isStale = () => generation !== requestGenerationRef.current
    _ensureMessagesLoading.add(loadingKey)
    void (async () => {
      try {
-        await materializeSessionFromServer(resolvedDirectory, sessionID, store)
+        await materializeSessionFromServer(resolvedDirectory, sessionID, store, { isStale })
      } catch {
        // Transient failure — next navigation or reconnect will retry
      } finally {
@@ -22,10 +22,11 @@ import {
 import { getSessionMaterializationStatus, materializeSessionSnapshots } from "./materialization"
 const SKIP_PARTS = new Set(["patch", "step-start", "step-finish"])
-const INITIAL_MESSAGE_PAGE_SIZE = 150
+const INITIAL_MESSAGE_PAGE_SIZE = 50
 const VSCODE_INITIAL_MESSAGE_PAGE_SIZE = 30
 const MOBILE_INITIAL_MESSAGE_PAGE_SIZE = 30
-const HISTORY_MESSAGE_PAGE_SIZE = 200
+const HISTORY_MESSAGE_PAGE_SIZE = 100
 const INITIAL_PAGE_EXPANSION_LIMITS = [100, 150] as const
 const VSCODE_INITIAL_PAGE_EXPANSION_LIMITS = [50, 80, 120] as const
 const MAX_SEEN_DIRS = 30
 const VSCODE_SESSION_CACHE_LIMIT = 4
@@ -40,6 +41,12 @@ const seenByDirectory = new Map<string, Set<string>>()
 // all request the same session during startup; coalesce them into one HTTP load.
 const syncSessionInflightByKey = new Map<string, Promise<void>>()
 // Per-session generation counter. When a newer syncSession request starts for
 // the same session, older in-flight requests become stale and must not write
 // to the store. This prevents rapid session switches (e.g. 1→2→3 in the
 // sidebar) from having each completed fetch fight for focus.
 const syncSessionGenerationByKey = new Map<string, number>()
 type SyncMeta = {
  limit: number
  cursor: string | undefined
@@ -88,6 +95,9 @@ const getInitialMessagePageSize = () => {
  if (isMobileSurfaceRuntime()) return MOBILE_INITIAL_MESSAGE_PAGE_SIZE
  return INITIAL_MESSAGE_PAGE_SIZE
 }
 const getInitialPageExpansionLimits = () => isConstrainedSessionRuntime()
  ? VSCODE_INITIAL_PAGE_EXPANSION_LIMITS
  : INITIAL_PAGE_EXPANSION_LIMITS
 const getDefaultMeta = (): SyncMeta => ({ limit: getInitialMessagePageSize(), cursor: undefined, complete: false, loading: false })
 function getPrefetchMeta(directory: string, sessionID: string): SyncMeta | undefined {
@@ -333,7 +343,7 @@ export function useSync() {
  // Load messages for a session
  const loadMessages = useCallback(
-    async (sessionID: string, options?: { before?: string; mode?: "replace" | "prepend" }) => {
+    async (sessionID: string, options?: { before?: string; mode?: "replace" | "prepend"; isStale?: () => boolean }) => {
      const m = getMetaFor(sessionID)
      if (m.loading) return
      setMetaFor(sessionID, { loading: true })
@@ -342,13 +352,13 @@ export function useSync() {
        const limit = options?.before ? HISTORY_MESSAGE_PAGE_SIZE : m.limit
        let page = await fetchMessages(sessionID, limit, options?.before)
-        // Constrained shells keep the initial page small for switch performance. Some
+        // Keep the initial page small for switch performance. Some sessions
-        // sessions have a very large final turn, so the latest 30 records can
+        // have a very large final turn, so the latest records can
        // contain only assistant/tool records and no user boundary. That makes
        // turn projection render an empty chat until the user manually loads
        // older messages. Expand only this initial tail fetch, with a hard cap.
-        if (!options?.before && isConstrainedSessionRuntime() && !page.complete && !hasUserMessage(page.session)) {
+        if (!options?.before && !page.complete && !hasUserMessage(page.session)) {
-          for (const nextLimit of VSCODE_INITIAL_PAGE_EXPANSION_LIMITS) {
+          for (const nextLimit of getInitialPageExpansionLimits()) {
            if (nextLimit <= limit) continue
            page = await fetchMessages(sessionID, nextLimit)
            if (page.complete || hasUserMessage(page.session)) break
@@ -362,6 +372,11 @@ export function useSync() {
          clearOptimistic(sessionID, messageID)
        }
        if (options?.isStale?.()) {
          setMetaFor(sessionID, { loading: false })
          return
        }
        const current = store.getState()
        const materialized = materializeSessionSnapshots(
          current,
@@ -373,6 +388,11 @@ export function useSync() {
          { skipPartTypes: SKIP_PARTS, mode: options?.mode === "prepend" ? "prepend" : "merge" },
        )
        if (options?.isStale?.()) {
          setMetaFor(sessionID, { loading: false })
          return
        }
        setMetaFor(sessionID, {
          limit: materialized.messages.length,
          cursor: merged.cursor,
@@ -404,6 +424,13 @@ export function useSync() {
      const existing = syncSessionInflightByKey.get(key)
      if (existing) return existing
      // This is a new request. Bump generation so any older request that
      // might still be finishing (e.g. from a previous component lifecycle)
      // knows it is stale and should not write to the store.
      const generation = (syncSessionGenerationByKey.get(key) ?? 0) + 1
      syncSessionGenerationByKey.set(key, generation)
      const isStale = () => syncSessionGenerationByKey.get(key) !== generation
      const current = store.getState()
      const m = getMetaFor(sessionID)
      const materialization = getSessionMaterializationStatus(current, sessionID)
@@ -449,7 +476,7 @@ export function useSync() {
                    assertSdkSuccess(response, "session.get")
                    return response
                  })
-                  if (result.data) {
+                  if (result.data && !isStale()) {
                    const nextSession = stripSessionDiffSnapshots(result.data)
                    const s = store.getState()
                    const sessions = [...s.session]
@@ -459,15 +486,30 @@ export function useSync() {
                    } else {
                      sessions.splice(idx.index, 0, nextSession)
                    }
-                    store.setState({ session: sessions })
+                    if (!isStale()) {
                      store.setState({ session: sessions })
                    }
                  }
                } catch (e) {
                  console.error("[sync] failed to fetch session", sessionID, e)
                }
              })()
            : Promise.resolve(),
-          shouldLoadMessages ? loadMessages(sessionID) : Promise.resolve(),
+          shouldLoadMessages ? loadMessages(sessionID, { isStale }) : Promise.resolve(),
        ])
        // Progressive mount: after the initial page resolves, if the session
        // isn't stale and the server indicated more messages, dispatch a
        // second fetch to prepend older history. The user sees the first page
        // immediately; the rest arrive shortly after. This gives the scroll
        // container headroom above the viewport so the "load older on
        // scroll-up" trigger fires before the user hits the absolute top.
        if (!isStale()) {
          const currentMeta = getMetaFor(sessionID)
          if (currentMeta.cursor && !currentMeta.complete) {
            loadMessages(sessionID, { before: currentMeta.cursor, mode: "prepend", isStale })
          }
        }
      })()
      syncSessionInflightByKey.set(key, promise)
@@ -0,0 +1,98 @@
 import { describe, expect, test } from 'bun:test';
 import type { Message, Part } from '@opencode-ai/sdk/v2/client';
 import type { State } from './types';
 import { EMPTY_USER_MESSAGE_HISTORY_SNAPSHOT, buildUserMessageHistorySnapshot } from './user-message-history';
 const message = (id: string, role: 'user' | 'assistant'): Message => ({
  id,
  role,
  sessionID: 'ses_1',
  time: { created: 1 },
 } as Message);
 const textPart = (id: string, text: string): Part => ({
  id,
  type: 'text',
  text,
 } as Part);
 const state = (partial: Partial<State>): Pick<State, 'session' | 'message' | 'part'> => ({
  session: [],
  message: {},
  part: {},
  ...partial,
 });
 describe('buildUserMessageHistorySnapshot', () => {
  test('returns a shared empty snapshot without a session id', () => {
    expect(buildUserMessageHistorySnapshot(state({}), '')).toBe(EMPTY_USER_MESSAGE_HISTORY_SNAPSHOT);
  });
  test('keeps history stable when assistant parts change', () => {
    const user = message('user_1', 'user');
    const assistant = message('assistant_1', 'assistant');
    const userParts = [textPart('part_user', 'hello')];
    const first = buildUserMessageHistorySnapshot(
      state({
        message: { ses_1: [user, assistant] },
        part: { user_1: userParts, assistant_1: [textPart('part_a', 'stream')] },
      }),
      'ses_1',
    );
    const second = buildUserMessageHistorySnapshot(
      state({
        message: { ses_1: [user, assistant] },
        part: { user_1: userParts, assistant_1: [textPart('part_a2', 'streaming')] },
      }),
      'ses_1',
      first,
    );
    expect(second).toBe(first);
    expect(second.history).toEqual(['hello']);
  });
  test('updates history when a user part changes', () => {
    const user = message('user_1', 'user');
    const first = buildUserMessageHistorySnapshot(
      state({
        message: { ses_1: [user] },
        part: { user_1: [textPart('part_user', 'hello')] },
      }),
      'ses_1',
    );
    const second = buildUserMessageHistorySnapshot(
      state({
        message: { ses_1: [user] },
        part: { user_1: [textPart('part_user_updated', 'updated')] },
      }),
      'ses_1',
      first,
    );
    expect(second).not.toBe(first);
    expect(second.history).toEqual(['updated']);
  });
  test('excludes user messages hidden by session revert state', () => {
    const beforeRevert = message('user_1', 'user');
    const reverted = message('user_2', 'user');
    const snapshot = buildUserMessageHistorySnapshot(
      state({
        session: [{ id: 'ses_1', revert: { messageID: 'user_2' } } as State['session'][number]],
        message: { ses_1: [beforeRevert, reverted] },
        part: {
          user_1: [textPart('part_user_1', 'kept')],
          user_2: [textPart('part_user_2', 'reverted')],
        },
      }),
      'ses_1',
    );
    expect(snapshot.history).toEqual(['kept']);
  });
 });
@@ -0,0 +1,98 @@
 import type { Message, Part } from '@opencode-ai/sdk/v2/client';
 import type { State } from './types';
 type UserMessageHistoryRecord = {
  message: Message;
  parts: Part[];
 };
 export type UserMessageHistorySnapshot = {
  sessionID: string;
  revertMessageID?: string;
  records: UserMessageHistoryRecord[];
  history: string[];
 };
 const EMPTY_PARTS: Part[] = [];
 const EMPTY_RECORDS: UserMessageHistoryRecord[] = [];
 const EMPTY_HISTORY: string[] = [];
 export const EMPTY_USER_MESSAGE_HISTORY_SNAPSHOT: UserMessageHistorySnapshot = {
  sessionID: '',
  revertMessageID: undefined,
  records: EMPTY_RECORDS,
  history: EMPTY_HISTORY,
 };
 const getPartText = (part: Part): string => {
  if (part?.type !== 'text') return '';
  const text = (part as { text?: unknown }).text;
  return typeof text === 'string' ? text : '';
 };
 const getFirstTextFromParts = (parts: Part[]): string => {
  for (const part of parts) {
    const text = getPartText(part);
    if (text.length > 0) return text;
  }
  return '';
 };
 const areRecordsEqual = (left: UserMessageHistoryRecord[], right: UserMessageHistoryRecord[]): boolean => {
  if (left === right) return true;
  if (left.length !== right.length) return false;
  for (let index = 0; index < left.length; index += 1) {
    if (left[index]?.message !== right[index]?.message || left[index]?.parts !== right[index]?.parts) {
      return false;
    }
  }
  return true;
 };
 export const buildUserMessageHistorySnapshot = (
  state: Pick<State, 'session' | 'message' | 'part'>,
  sessionID: string,
  previous: UserMessageHistorySnapshot = EMPTY_USER_MESSAGE_HISTORY_SNAPSHOT,
 ): UserMessageHistorySnapshot => {
  if (!sessionID) {
    return EMPTY_USER_MESSAGE_HISTORY_SNAPSHOT;
  }
  const messages = state.message[sessionID] ?? [];
  const session = state.session.find((candidate) => candidate.id === sessionID);
  const revertMessageID = (session as { revert?: { messageID?: string } } | undefined)?.revert?.messageID;
  const records: UserMessageHistoryRecord[] = [];
  for (let index = messages.length - 1; index >= 0; index -= 1) {
    const message = messages[index];
    if (message.role !== 'user') {
      continue;
    }
    if (revertMessageID && message.id >= revertMessageID) {
      continue;
    }
    records.push({
      message,
      parts: state.part[message.id] ?? EMPTY_PARTS,
    });
  }
  if (records.length === 0) {
    return previous.sessionID === sessionID && previous.revertMessageID === revertMessageID && previous.records.length === 0
      ? previous
      : { sessionID, revertMessageID, records: EMPTY_RECORDS, history: EMPTY_HISTORY };
  }
  if (previous.sessionID === sessionID && previous.revertMessageID === revertMessageID && areRecordsEqual(previous.records, records)) {
    return previous;
  }
  const history: string[] = [];
  for (const record of records) {
    const text = getFirstTextFromParts(record.parts);
    if (text.length > 0) {
      history.push(text);
    }
  }
  return { sessionID, revertMessageID, records, history };
 };