[Alb11747]

Problem

After a long Claude conversation becomes cold, selecting Codex can leave Compact next enabled and send an automatic /compact on Codex before queueing the actual message. The parent chat view keeps the conversation's provider lock while the composer permits handoff, so the recommendation and live send destination disagree.

Reproduce with a stopped Claude conversation containing 250k tokens past its cache TTL: select Codex and send an ordinary message. The expected result is one normal handoff/message dispatch. The affected source instead dispatches Codex /compact with idleCompaction: "onReturn", then queues the message.

Fixes #25943. Related: #23086, which concerns evaluating the saved Claude destination when switching back.

Change

Resolve the parent's selection the same way as the composer, and bind resume-compaction recommendations to the selected provider instance, saved conversation, and observed context. The composer hides recommendations that do not match its selection. The send handler checks the live destination again after uploads/settings preparation, so a replaced, refreshed, or compacted conversation cannot reuse an older recommendation. The optimistic message's queue/steer classification and scroll anchor follow that final send plan.

Returning to a saved long, cold Claude conversation still offers compaction using that destination's context. Manual /compact, full-history choices, warm-cache behavior, original message/attachments, and normal dispatch modes retain their existing behavior.

Scope and approval

The issue has not received maintainer triage; no prior approval is claimed. This is submitted under the focused obvious-bug exception: an existing Claude-only recommendation is being applied to a different provider or conversation. The changes carry that existing eligibility through its UI and send boundary, without introducing a setting, workflow, or product default. All eight files address this same mismatch and its regression coverage.

Web and desktop share this composer path. Native mobile, agent/MCP sends, and scheduled sends do not inject this web on-return compaction. The separate before-cache-expiry service already checks its Claude provider/conversation and is unchanged.

Verification

• vp run check:changed upstream/main: formatting, lint, knip, affected typechecks, and all 65 tests across three files passed on the upstream-only branch.
• The failing regression and full AppRoot fixture reproduced the original behavior on affected source 54aeb9ba2df2. The fixture recorded Codex /compact followed by the queued message before the fix, versus exactly one Codex message after it. The source/fixture details are in [Bug]: Switching from an idle Claude thread to Codex still triggers automatic /compact #25943.
• Actual send-hook browser tests cover stale parent Claude eligibility with live Codex selection, preserving uploaded attachments and one actual message. Deferred uploads cover conversation replacement, context refresh, usage refresh, and compaction with an unchanged conversation ID; these cases send directly and clear the optimistic queued marker when the recommendation becomes stale. Controls preserve explicit queue/steer intent and anchoring, same-Claude and Codex-to-saved-Claude compaction, manual commands, opt-outs, and warm/small context.
• Exact-commit fork CI passed on current head bc2ce013fdf27d591919c8cc52d5b8d1f022fe50: Quality, Web tests, Tests, and all three server shards are green. The preceding revision's full CI passed on 1fe0a60a58fcbb11e3f52663abf06ef91a9bdf98, based on upstream 5e9d56416f6b: Quality, Web tests, Tests, and all three server shards were green.
• Earlier CI and a focused local check on the earlier upstream base exposed an unrelated storageCleanup.test.ts invalid-gitfile diagnostic failure. The subsequent full run above passed. The server/package trees are unchanged from upstream in this PR; the separate fork cleanup compatibility fix is excluded.

Integrated UI captures use a synthetic full-AppRoot environment with mocked providers. No provider CLI, paid model call, or live database was used. The captures were made on the affected/fixed fork source before the upstream-only port; the port contains the same production fix. Slow-request toasts in the fixed fixture are caused by deliberately unanswered mock RPCs. Packaged desktop, native mobile, and post-install live-provider execution were not tested.

After selecting Codex: affected source	After selecting Codex: fixed source

Returning to the saved cold Claude destination restores the intended suggestion:

Model/harness: GPT-6.1 Sol through Codex in T3 Code; independent reviews by GPT-6.1 Sol at xhigh effort. OpenAI/Codex models only.

[chatgpt-codex-connector]

Codex Review Summary

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Review	Status	Commit	Review trigger
📝 Code Review	⚠️ Failed 2026-10-27T21:30:19.669117Z We couldn’t complete this review. Comment @codex review to try again.	bc2ce01	Manual request

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[macroscopeapp]

Approvability

Verdict: Would Approve

Macroscope's review found this PR approvable — Resume compaction is scoped to the selected Claude conversation and revalidated after uploads, reducing unintended compaction when switching providers. The reported temporary queue-display issue remains covered by the separate correctness gate.

Needs human approval because:

• 1 blocking correctness issue found at or above your repo's Minimum Blocking Severity

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[coderabbitai]

No actionable comments were generated in the recent review.

Recent review info

Run configuration

• Source mode: Auto
• Repository: pingdotgg/t3code
• Branch: main
• File: .coderabbit.config.ts
• Commit: 5e9d564
• Layers: Repository TS config
• Review profile: CHILL
• Plan: Advanced
• Run ID: 4f1a2fc4-c77e-40a5-b74a-85c51e4a94cd

Commits

Reviewing files that changed from the base of the PR and between 1fe0a60 and bc2ce01.

Files selected for processing: 2

• apps/web/src/components/chat/useComposerSend.browser.test.tsx
• apps/web/src/components/chat/useComposerSend.ts

Included review availability: This review used your included allowance. Your plan provides up to 10 included reviews per hour; 8 remain after this review.

Walkthrough

Resume-compaction recommendations now include provider instance, destination thread, usage, and update-time data. ChatView resolves recommendations from matching Claude provider threads. The planner, composer, and send hook verify the selection and current context before compaction.

Changes: Resume compaction selection and dispatch

Layer / File(s)	Summary
Resolve provider-thread context apps/web/src/components/chat/ContextWindowMeter.logic.ts, apps/web/src/components/chat/ContextWindowMeter.logic.test.ts	New helpers derive context from provider-thread turns, select the latest matching root thread, and return tokens only for the matching Claude instance. Tests cover thread resolution, selection, and offer conditions.
Resolve and pass the recommendation apps/web/src/components/ChatView.tsx	ChatView resolves recommendations from the matching Claude provider thread and passes structured data to the composer and send hook. Provider selection uses the handoff-aware locked provider.
Scope compaction to the selection apps/web/src/components/ChatView.logic.ts, apps/web/src/components/chat/ChatComposer.tsx, apps/web/src/components/ChatView.logic.test.ts	The planner checks the selected provider, instance, and destination thread. The composer derives eligible tokens from the recommendation. Tests cover provider switches, destination changes, and full-history mode.
Revalidate before dispatch apps/web/src/components/chat/useComposerSend.ts, apps/web/src/components/chat/useComposerSend.browser.test.tsx	The send hook checks saved eligibility against current context and rereads the turn plan after upload and settings persistence. Browser tests cover stale context and Claude destination dispatch.

Priority: Normal

Estimated code review effort: 3 (Moderate) | ~25 minutes

Change: Bug fix · Severity of issue fixed: Medium

Sequence Diagram(s)

sequenceDiagram
  participant ChatView
  participant ChatComposer
  participant useComposerSend
  participant ProviderThread
  ChatView->>ProviderThread: Resolve matching Claude thread and context
  ChatView->>ChatComposer: Pass structured resume-compaction recommendation
  ChatComposer->>useComposerSend: Send with selected provider and destination
  useComposerSend->>ProviderThread: Revalidate source timestamp and token usage
  useComposerSend->>useComposerSend: Replan after uploads and settings persistence

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Possibly related issues

• pingdotgg/t3code#23086 — This change evaluates resume-compaction eligibility against the selected Claude instance and saved destination context.

Possibly related PRs

• pingdotgg/t3code#24008 — Both changes govern automatic compaction in planComposerTurn; that PR preserves the exclusion for explicit /compact commands with instructions.
• pingdotgg/t3code#25986 — Both changes address stale resume-compaction eligibility during provider switches. This PR also resolves and revalidates destination context.
• pingdotgg/t3code#24334 — Both changes use the web on-return compaction path. That PR changes the generated /compact turn’s presentation and idle-compaction marker.

Suggested labels: bugfix

Suggested reviewers: juliusmarminge

Merge Risk: Minimal · up to bc2ce

No merge-blocking issue is established; the change is ready to merge after normal checks.

Pre-merge checks: 4

Check name	Status	Explanation
Title check		The title clearly and concisely describes the main fix: scoping resume compaction to the selected provider conversation.
Linked Issues check		Issue [#25943] requires normal dispatch after switching from Claude to Codex, while preserving deliberate /compact, and compaction when returning to an eligible saved Claude conversation. ChatView…
Out of Scope Changes check		The production changes and tests address the stale on-return compaction path described by [#25943]. They do not add unrelated settings, workflows, provider integrations, native-mobile paths, scheduled…
Description check		The pull request description follows the required template. It clearly states the problem, expected behavior, reproduction steps, implementation, scope and approval rationale, verification results, li…

Full details: Linked Issues check

Explanation

Issue [#25943] requires normal dispatch after switching from Claude to Codex, while preserving deliberate /compact, and compaction when returning to an eligible saved Claude conversation. ChatView and ChatComposer now use matching provider selection. ContextWindowMeter.logic.ts scopes eligibility to the provider instance, provider thread, and context. planComposerTurn and useComposerSend recheck eligibility at send time. Tests cover Codex handoff, saved-Claude return, stale context, attachments, dispatch modes, manual commands, full-history choices, and warm context.

Full details: Out of Scope Changes check

Explanation

The production changes and tests address the stale on-return compaction path described by [#25943]. They do not add unrelated settings, workflows, provider integrations, native-mobile paths, scheduled sends, or before-cache-expiry service changes. Related issue [#23086] remains contextual and is not treated as an additional objective.

Full details: Description check

Explanation

The pull request description follows the required template. It clearly states the problem, expected behavior, reproduction steps, implementation, scope and approval rationale, verification results, limitations, UI evidence, and model/harness details.

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[Alb11747]

@codex review

Retrying the hosted review once after its previous failure to complete. Current head: bc2ce013fdf27d591919c8cc52d5b8d1f022fe50. The optimistic queue-state finding is fixed, and local checks pass with 65 focused tests.

[chatgpt-codex-connector]

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[juliusmarminge]

Thank you @Alb11747 for the careful reproduction and fix. #25986 fixes the same issue (#25943) with a smaller change: the resume-compaction offer now also requires that the send resumes the current conversation, reusing the handoff rule ChatView already computes, with a browser test that fails on main. We're keeping that one to keep the diff small and closing this as a duplicate. Your write-up and the send-time recheck idea are noted on the issue's record; if a stale-recommendation case shows up after https://git.cafe/pingdotgg/t3code/pulls/25986 lands, this PR is where we'll start.