fix(ui): spend the retained Agent-switch submission once custody lands

[AmT42]

Problem

On the 0.2 dev lane, after a successful in-session Agent switch ("Continue with another agent"), the composer's Agent picker shows only models, no Agents. Reloading the page or leaving and re-entering the session does not bring them back. The only way out is to send an ordinary message to the current Agent: once it is accepted, the Agents reappear.

Observed on 0.2.14-dev.2 CLI, self-hosted relay 0.2.15-dev.1, web UI 0.2.15-dev.363, macOS. It reproduced after both directions of a Codex → Claude → Codex → Claude round trip; every switch itself worked correctly (same native thread resumed, catch-up only).

Workaround for users until this lands: send one normal message to the current Agent, wait for its reply, then reopen the picker.

Cause

• Before dispatching a switch, SessionView records the exact submission (localId + wire input) inside the armed continuation in the session draft (routing.agentContinuation). This is intentional custody, so a retry after an unknown outcome reuses the same localId.
• useInSessionAgentPickerControls hides the Agent rail while that retained submission exists (retainedSubmissionArm !== null), so a second switch cannot overwrite the only retry identity.
• b15d7bc6a ("preserve composer custody through synchronized session updates") moved the arm onto the session-draft repository. It removed clearArmedContinuationSubmissionIfCurrent from the hook, along with its two call sites in SessionView: the outcome-disposition clear and the remount custody clear.
• Since then, nothing removes the retained submission once canonical custody has the localId. clearArmedContinuation() deliberately keeps a persisted submission. An ordinary send clears every captured draft field through clearSessionDraftCurrentness, routing.agentContinuation included, which is why the workaround works.
• The SessionView test mock still exposes clearArmedContinuationSubmissionIfCurrent, but no test asserted it was called, so the regression went unnoticed.

v0.3 still has the method and both call sites, so it is not affected. This PR restores 0.2 parity.

Change

• useInSessionAgentPickerControls: re-add clearArmedContinuationSubmissionIfCurrent(submission). It compare-clears the persisted arm only when its retained submission has the same localId. A newer arm, which never carries that localId, is left alone.
  • Unlike v0.3, it compares on localId rather than a full JSON.stringify of the submission. The persisted value is read back through the draft schema while a live arm holds the raw object, and localId is already this transition's documented compare-clear key. Happy to switch to the v0.3 comparator if you prefer exact parity.
• SessionView: call it from both custody owners, right after clearArmedContinuationSubmissionDraftsIfCurrent(submission), as before b15d7bc6a and as on v0.3.

Tests

RED before the fix, GREEN after:

• useInSessionAgentPickerControls.armDraft.test.tsx
  • "offers the other Agents again once canonical custody consumes the submitted switch": arm, record the submission, switch the running Agent, then assert the rail is empty, call the clear, and assert the persisted arm is gone and the other Agent is offered again.
  • "leaves a newer arm alone when custody consumes the submission it replaced".
• SessionView.sendAttachmentsResumable.feat.attachments.uploads.test.tsx
  • New case "spends the retained submission once the switch is admitted", covering the accepted outcome.
  • The existing "custody only lands later" case now also asserts the persisted clear.

Validation run locally (macOS, LC_ALL=en_US.UTF-8; two picker tests assert English copy and fail under a French locale on a clean dev too):

• vitest run sources/components/sessions/agentPicker sources/components/sessions/shell/SessionView.sendAttachmentsResumable…: 104 passed.
• Adjacent suites (sessions/shell, agentTransition, sessionDrafts, session/input, useDraft, existingSessionDraftSemanticValues, sessionDraftSyncRuntime, …): 122 files, 1196 tests passed.
• yarn typecheck in apps/ui: passed.
• Bundle check: the installed 0.2.15-dev.363 web bundle does not contain clearArmedContinuationSubmissionIfCurrent. A web bundle built from this branch with scripts/pipeline/release/build-ui-web-bundle.mjs does.
• Not yet run: a live switch in the browser against the patched bundle. I'm opening this as a draft and will mark it ready after that check.

AI assistance

This was found and fixed with AI agents, under my direction:

• I asked Codex (GPT, with computer use) to reproduce the problem in the real web UI. It reproduced it twice, ruled out reload, found the workaround, and pointed at useInSessionAgentPickerControls.
• I asked Claude Code (Claude Opus 5.5) to find the root cause in the source and fix it test-first. It traced the retained-submission rail guard to the missing custody clear, found the commit that removed it, and checked that v0.3 still has it.
• The instruction was to fix it at the source and open a PR. Claude Code chose the smallest fix: restore the previous lifecycle at its existing owners rather than add a new mechanism. The diff, the tests and this description were written by Claude Code. The checks listed above are the ones that actually ran.

🤖 Generated with Claude Code

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Note

Spend retained Agent-switch submission once canonical custody lands in SessionView

• Adds clearArmedContinuationSubmissionIfCurrent to useInSessionAgentPickerControls. It clears a persisted continuation submission only when its localId matches the submitted snapshot, so newer arms are left alone.
• Wires the callback into SessionViewLoaded (SessionView.tsx). Both canonical continuation reconciliation effects invoke it with the live retained submission, so a retained switch submission is removed once custody is present.
• Adds tests for the localId-fenced cleanup, including a stale-snapshot case where a newer arm stays intact, and extends resumable-send tests to assert the retained submission is spent when the switch is admitted.
• Behavioral Change: a retained armed submission in a scoped session draft is now removed on custody, restoring the other Agents in the picker; previously it stayed persisted.

^{Macroscope summarized eda8607.}

Summary by CodeRabbit

• Bug Fixes
  • Continuation submissions remain available when their outcome is unknown, including after reopening a session.
  • Once a submission is accepted or matched to a pending message, its armed continuation is cleared.
  • Clearing an older submission no longer removes a newer armed agent or overwrites newer composer text.
  • Restored agent options use consistent target identifiers, and stale or ineligible armed agents are cleared.

[coderabbitai]

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Reviewing files that changed from the base of the PR and between 6b942db and b590ebf.

📒 Files selected for processing (1)

• apps/ui/sources/components/sessions/shell/SessionView.directSessions.test.tsx

🚧 Files skipped from review as they are similar to previous changes (1)

• apps/ui/sources/components/sessions/shell/SessionView.directSessions.test.tsx

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Walkthrough

The picker now conditionally clears persisted continuation submissions by identity. SessionView uses this operation during draft outcome reconciliation and canonical custody handling. Tests cover agent target keys, remounts, delayed custody, and preservation of newer draft state.

Changes

Continuation submission custody

Layer / File(s)	Summary
Picker submission cleanup apps/ui/sources/components/sessions/agentPicker/useInSessionAgentPickerControls.tsx, apps/ui/sources/components/sessions/agentPicker/useInSessionAgentPickerControls.armDraft.test.tsx	The picker exposes a compare-and-clear operation for armed submissions. Tests use typed agent:<id> target keys and cover restored arms, submission snapshots, and stale submissions.
Session outcome reconciliation apps/ui/sources/components/sessions/shell/SessionView.tsx, apps/ui/sources/components/sessions/shell/SessionView.directSessions.test.tsx	SessionView compare-clears the persisted submission when reconciliation or canonical custody clears a submitted draft. Direct-session tests cover accepted and unknown outcomes, delayed pending-message custody, and preserving newer composer and continuation state.

Priority: ➖ Normal

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

Change: Bug fix

Merge Risk: ⚪ Minimal · up to b590e

The added custody coverage exercises the intended cleanup path; no issue identified here needs resolution before merge.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 13.33% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 15 functions across 5 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly describes the primary UI fix: clearing a retained Agent-switch submission after custody lands.
Description check	✅ Passed	The description explains the problem, cause, implementation, tests, validation results, and AI assistance. It does not use the template headings exactly and omits the checklist and screenshots section…
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.

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[greptile-apps]

Confidence Score: 5/5

[Medium risk] Adds submission cleanup logic to the agent picker state.

The PR appears safe to merge; the previous coverage concern is addressed and no new blocking issue was found.

What we checked:

• Old cleanup removes newer choices: The picker reads the current saved arm and clears it only when its submission has the expected localId. A different arm does not pass that check.

Summary

Restores cleanup of a saved Agent-switch submission after the message is accepted or appears in canonical pending state.

• SessionView decides when admission has landed. The picker clears only the saved submission with the matching localId.
• The follow-up replaces spy-only coverage with tests using the real picker and draft repository.
• The previous coverage finding is addressed. No new actionable issues were found.
• This review inspected source and tests; it did not rerun tests, typecheck, or browser checks.

Diagram

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A[Submit Agent switch] --> B[Save submission and localId]
    B --> C{Admission known?}
    C -->|Unknown| D[Keep saved submission for retry]
    D -->|Matching pending message arrives| E[SessionView confirms admission]
    C -->|Accepted| E
    E --> F[Picker compares saved localId]
    F -->|Matches| G[Repository clears saved arm]
    F -->|Different or absent| H[Leave newer choice alone]
    G --> I[Other Agents become available]

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_{Reviews (2) · Last reviewed commit: "test(ui): await draft cleanup around sem..." · Reviewed by Greptile}

[coderabbitai]

Actionable comments posted: 1

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Inline comments:
Review comments at
@apps/ui/sources/components/sessions/shell/SessionView.directSessions.test.tsx:
- Line 3683: Await deleteSessionDraft in the test setup before seeding semantic
values so its asynchronous storage preparation cannot remove the seeded replica.

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[happier-bot]

The recommended refinements are now on the author branch at b590ebf.

Thanks @AmT42 for restoring cleanup through the existing picker/repository owner. The production change belongs at the custody boundary: SessionView resolves admission, the picker compares the submitted identity, and SessionDraftRepository owns persistence. No competing store or cleanup decision was found in the affected corridor.

Greptile's coverage concern was valid. The follow-up keeps the real picker and draft repository and verifies persisted cleanup, restored Agent choices, unknown-outcome remount recovery, and preservation of newer text or a different arm. Removing the two production cleanup calls produces the intended regression failures. CodeRabbit's asynchronous fixture-deletion concern was also valid; the latest commit awaits setup and final cleanup. The generic docstring-percentage warning does not demonstrate a defect and does not justify boilerplate here.

Validation: 255 tests across seven relevant files passed for the composed coverage change; all 84 direct-session tests passed after the await correction. UI package typecheck passed for the coverage change. A real browser scenario passed both switch directions, picker reopening and reload, using disposable services and fake provider boundaries. The final browser-spec package typecheck also passed.

The 0.3 production owner already satisfies the cleanup intent, so the port adapts regression coverage rather than duplicating production logic. Eight relevant composed cases pass, including an acknowledged owner-metadata update. Destination whole-package validation still has unrelated checkout errors; this is not a claim that the entire 0.3 checkout is green. The separately reported composer/backend alignment work remains outside this PR.

@greptileai please review the current head, especially the real persisted-custody coverage. CodeRabbit can review the latest incremental commit through the normal push trigger.

cc @leeroybrun

Posted on behalf of @leeroybrun.

[happier-bot]

Current-head validation is complete for b590ebf. CI run 37659935783, attempt 3 passed: all four UI unit shards, UI integration, all four Playwright shards, typecheck, and production build smoke. The source-CI planner skipped unaffected and opt-in lanes.

The first executing attempt stalled in apt-get update during Sapling installation, before the fourth shard ran tests. A native failed-job rerun preserved the successful jobs and completed that shard. No code, timeout or test gate was changed for the infrastructure failure.

CodeRabbit approved the current head, Greptile reports no remaining actionable findings, and both confirmed threads are resolved. GitHub now reports APPROVED, MERGEABLE and CLEAN. The correction uses the existing custody/picker/repository owners and preserves newer drafts and arms; no additional production refinement is recommended. Recommend merging; no merge has been performed.

The 0.3 cleanup intent already holds in its evolved owner and has adapted regression coverage. The separate local composer alignment work remains outside this PR; its destination package/live validation limitations remain recorded separately.

cc @leeroybrun

Posted on behalf of @leeroybrun.

[leeroybrun]

Thank you @AmT42 !