ChatView subscribed to the active thread's live projection. Every streamed assistant or reasoning delta replaced a turn item, so ChatView re-rendered once per delta, and its compiled output rebuilt the uncached region inside ThreadFindCanvas. A long reply re-rendered ChatView about once per delta.
ChatView now reads a quiet view of the thread, and the components that show the streamed text read the live one:
quietThreadAtom and quietVisibleTurnItemsAtom, next to the existing detail atoms in threadDetail.ts. They keep the previous value while the only change is text streamed into existing assistant or reasoning items. Any other change passes through: a new item, a status or streaming change, runs, requests, sessions, plans. Mobile can use the same atoms.quietThreadAtom returns a ThreadStructure (in models.ts): the projection without updatedAt, with assistant and reasoning items lacking text and updatedAt. A reader of the quiet thread can't pick up a stale value, because the type and the runtime object no longer have it. The structure is built only when sameThreadStructure sees a change. Items are stripped once each (WeakMap), so between changes the atom returns the same object and allocates nothing per delta. The comparison overlays the stripped form of the previous item on the next one, so the strip function and the ignored fields can't drift apart.deriveThreadRuntime copied projection.updatedAt into runtime.updatedAt. ChatView now uses deriveThreadStructureRuntime, which has no updatedAt. The shell-less fallback (presentThreadShellFromProjection) reads the live updatedAt through useThreadUpdatedAt, subscribed only while there is no shell.projection.updatedAt for its time. It now falls back to its run's timestamps.ThreadTimeline (new, 65 lines) wraps MessagesTimeline. It reads the live visible turn items, derives the rows it renders, and remembers the ready timeline that a thread switch paints. That layout effect moved here from ChatView, so the held paint has the current text. ChatView still derives rows from the quiet items for its own uses: anchoring, prompt history, rewind and the draft hero.useThreadFind reads the live projection itself instead of taking it as a prop, so open find results still refresh while a reply streams. Only the find provider re-renders per delta, and its children are unchanged elements.Renders, median of 3 (rc-init.js), on the current head. Before (#23117's base, 3b95e7831b) and after ran back to back on the same seeded thread with Codex:
| Interaction | before: total | after: total | before: ChatView | after: ChatView | before: MessagesTimeline | after: MessagesTimeline |
|---|---|---|---|---|---|---|
| Streamed reply, 15 short lines | 2,520 | 2,390 | 22 | 18 | 22 | 22 |
| Streamed reply, 40 lines | 3,493 | 3,204 | 32 | 18 | 32 | 31 |
| Thread switch and back | 2,550 | 2,394 | 13 | 10 | 13 | 10 |
| Type 20 chars | 166 | 167 | 1 | 1 | 1 | 1 |
| Right panel open and close | 480 | 484 | 4 | 4 | 4 | 4 |
| Interaction | before | after |
|---|---|---|
| Streamed reply, 15 short lines | 2,564/22/22, 2,355/20/20, 2,520/23/23 | 2,678/21/25, 2,390/17/22, 2,293/18/21 |
| Streamed reply, 40 lines | 4,214/40/40, 3,406/32/32, 3,493/32/32 | 3,530/20/34, 3,204/18/31, 3,170/17/30 |
| Thread switch and back | 3,303/19/19, 2,550/13/13, 2,206/11/11 | 3,274/19/19, 2,394/10/10, 2,132/10/10 |
| Type 20 chars | 166/1/1 ×3 | 167/1/1 ×3 |
| Right panel open and close | 491/4/4, 480/4/4, 480/4/4 | 495/4/4, 484/4/4, 484/4/4 |
ChatView renders per reply no longer grow with the reply's length: 18 for both the short and the long reply, against 22 and 32 before. The remaining renders come from run, session, provider-turn and shell changes. ChatView reads each of those (stop button, working state, runtime, token usage). Totals fall by 5–8%. Markdown rows inside the timeline make up most of the rest, and they render once per delta either way. The first thread switch in each set includes a cold history load, which is why it runs high on both sides. A skipped ChatView render costs more than its count suggests: in an earlier profile it averaged about 14 ms of self time.
| File | before | after |
|---|---|---|
| ChatView.tsx | 3,896 | 3,908 |
| chat/ThreadTimeline.tsx | 65 |
Tested:
threadDetail.test.ts (new) covers what the quiet atom holds through and what it passes on, that the atom keeps its identity through text and updatedAt changes, and that stripped fields are absent at runtime. threads-atoms.test.ts, threadRequests.test.ts, threadExecution.test.ts, session-logic.test.ts, ChatView.logic.test.ts and contextWindow.test.ts pass.🤖 Generated with Claude Code
Review completed
Skipped - Not affected
Verdict: Needs Human Approval
Macroscope's review found this PR requires human approval — This PR substantially changes production thread-state subscriptions and timeline rendering by introducing a quiet/live projection split and a new timeline component. The change spans the central ChatView and shared client-runtime abstractions, so its broader runtime effects merit human review.
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✅ Thread transfer remains within every enforced ceiling.
| Provider | Metric | Main baseline | This PR | Impact | PR ceiling | |
|---|---|---|---|---|---|---|
| Codex | Total thread wire | 5.0 KiB | 5.0 KiB | 0 B (0.0%) | 6.8 KiB | ✅ |
| Codex | Thread snapshot wire | 3.8 KiB | 3.8 KiB | 0 B (0.0%) | 4.9 KiB | ✅ |
| Codex | Live turn WebSocket wire | 1.2 KiB | 1.2 KiB | 0 B (0.0%) | 2.0 KiB | ✅ |
| Codex | Live turn WebSocket decoded | 20.9 KiB | 20.9 KiB | 0 B (0.0%) | 29.3 KiB | ✅ |
| Codex | Live turn messages | 2 | 2 | 0 (0.0%) | 8 | ✅ |
| Claude | Total thread wire | 5.0 KiB | 5.0 KiB | +24 B (+0.5%) | 6.8 KiB | ✅ |
| Claude | Thread snapshot wire | 3.8 KiB | 3.8 KiB | 0 B (0.0%) | 4.9 KiB | ✅ |
| Claude | Live turn WebSocket wire | 1.2 KiB | 1.2 KiB | +24 B (+2.0%) | 2.0 KiB | ✅ |
| Claude | Live turn WebSocket decoded | 21.2 KiB | 21.2 KiB | +41 B (+0.2%) | 29.3 KiB | ✅ |
| Claude | Live turn messages | 1 | 2 | +1 (+100.0%) | 8 | ✅ |
Baseline: 3b95e78 · PR result: 0c8b651 · Source CI: success
10 historical turns, 5 command tools per turn, 878.9 KiB retained MCP result per historical turn, and a 1.05 MiB retained result in the measured turn.
Updated in place by a trusted workflow. PR artifacts are strictly validated and never executed.
No actionable comments were generated in the recent review. 🎉
0d11c0aa-8c68-41b8-991a-fb4bed45304bReviewing files that changed from the base of the PR and between c22776b1927faefd332ed4a6b7c45912229815b3 and 0c8b6515df8d597e318ee8f4f3d30da07d84eea7.
apps/web/src/components/ChatView.logic.tsapps/web/src/components/ChatView.tsxapps/web/src/components/chat/useAttachmentPreviewHandoff.tsapps/web/src/components/chat/useComposerSelection.tsapps/web/src/components/chat/usePendingThreadRequests.tsapps/web/src/components/chat/useQueuedRunEdit.tsapps/web/src/components/chat/useTimelineFollow.tsapps/web/src/components/chat/useTimelineRewind.tsapps/web/src/components/chat/useWorktreeSetup.tsapps/web/src/lib/contextWindow.tsapps/web/src/session-logic.tsapps/web/src/state/entities.tspackages/client-runtime/src/handoff.tspackages/client-runtime/src/state/models.tspackages/client-runtime/src/state/threadDetail.test.tspackages/client-runtime/src/state/threadDetail.tspackages/client-runtime/src/state/threadExecution.tspackages/client-runtime/src/state/threadRequests.tspackages/client-runtime/src/state/threadWorkflows.tspackages/client-runtime/src/state/turnItemPresentation.tspackages/shared/src/orchestrationV2ThreadError.tsIncluded review availability: This review used your included allowance. Your plan provides up to 10 included reviews per hour; 1 remain after this review.
The changes add quiet thread structures and selectors, update runtime and other consumers to use structure-based data, and move timeline entry selection and persistence into ThreadTimeline. ChatView filters incomplete rows and accounts for streamed rows in timeline loading decisions.
Changes: Thread Rendering
| Layer / File(s) | Summary |
|---|---|
Quiet thread structures packages/client-runtime/src/state/models.ts, packages/client-runtime/src/state/threadDetail.ts, packages/client-runtime/src/state/threadDetail.test.ts, apps/web/src/state/entities.ts, apps/web/src/components/chat/useAttachmentPreviewHandoff.ts | Thread structure types omit streamed text and timestamps. Quiet atoms retain prior structures when only those fields change. Selector hooks expose quiet projections, update timestamps, and visible turn items. Tests cover structure comparison and quiet atom behavior. |
Structure-based derivation and consumers packages/client-runtime/src/state/threadExecution.ts, packages/client-runtime/src/state/threadRequests.ts, packages/client-runtime/src/state/threadWorkflows.ts, packages/client-runtime/src/state/turnItemPresentation.ts, packages/client-runtime/src/handoff.ts, packages/shared/src/orchestrationV2ThreadError.ts, apps/web/src/components/ChatView.logic.ts, apps/web/src/components/chat/*, apps/web/src/lib/contextWindow.ts, apps/web/src/session-logic.ts, apps/web/src/components/ChatView.tsx | Runtime, request, workflow, handoff, and presentation inputs now use thread structure types. Plan timestamps use matching plan-item timestamps when available, with run and thread timestamps as fallbacks. Timeline follow releases its anchor under the described reasoning and live-follow conditions. |
Timeline selection and ChatView integration apps/web/src/components/chat/ThreadTimeline.tsx, apps/web/src/components/ChatView.tsx, apps/web/src/components/chat/useThreadFind.ts | ThreadTimeline selects draft or server entries, resolves remembered timelines during thread switches, remembers eligible ready timelines, and renders through MessagesTimeline. ChatView builds server entries from complete rows and includes streamed rows in its loading-state decision. useThreadFind obtains content through useThreadProjection. |
Priority: ⬇️ Low
Estimated code review effort: 4 (Complex) | ~45 minutes
Change: Refactor
Possibly related issues
Possibly related PRs
ChatView through quiet thread data and separate live timeline rendering.Suggested reviewers: t3dotgg, maria-rcks
0c8b6Streaming replies and find results retain their live update paths. No actionable merge-blocking issue remains after normal checks.
Failed Failed checks: 1 warning
| Check name | Status | Explanation | Resolution |
|---|---|---|---|
| Description check | Warning | The description clearly explains the performance problem, implementation, verification results, measurements, and known test gaps. It does not provide the required scope and approval information, and … | Add a Scope and approval section with the triaged issue or explicit maintainer approval, or explain why the change qualifies as an approved focused fix. Add before/after screenshots and a recording if needed to show UI behavior. If an agent… |
| Check name | Status | Explanation |
|---|---|---|
| Title check | Passed | The title clearly and concisely describes the primary performance change: streamed reply text no longer causes ChatView to re-render. |
| Linked Issues check | Passed | Check skipped because no linked issues were found for this pull request. |
| Out of Scope Changes check | Passed | Check skipped because no linked issues were found for this pull request. |
Explanation
The description clearly explains the performance problem, implementation, verification results, measurements, and known test gaps. It does not provide the required scope and approval information, and it does not include the required before/after screenshots for the UI changes. The agent disclosure also identifies Claude Code but does not state the model and harness.
Resolution
Add a Scope and approval section with the triaged issue or explicit maintainer approval, or explain why the change qualifies as an approved focused fix. Add before/after screenshots and a recording if needed to show UI behavior. If an agent was used, end the description with the model and harness used.
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