[iXab3r]

Problem

After changing the Claude model in a thread, every send to another provider is refused:

The previous provider is still running background agents or commands, and switching would end them.

Nothing is running and there is no Stop button. Only Force stop clears it.

T3 changes the model on the running CLI. The CLI answers with an echo, <local-command-stdout>Set model to …</local-command-stdout>, before the next turn starts. T3 kept that echo as the start of a background wake, and nothing cleared it.

flowchart TD
    A["Send with a new Claude model"] --> B["T3 calls setModel on the running CLI"]
    B --> C["CLI echoes: Set model to …"]
    C --> D["Before: kept as a background wake<br/>Now: dropped"]
    D --> E["Turn runs and ends"]
    E --> F["Send to another provider<br/>Before: refused<br/>Now: hand-off starts"]
    classDef changed fill:#fef3c7,stroke:#d97706,color:#78350f
    class D,F changed

Loading

	Before	Now
Echo of setModel, no turn active	❌ Kept as a background wake	✅ Dropped
Thread after the turn ends	❌ Reports background work until Force stop	✅ Idle
Send to another provider	❌ Refused	✅ Hand-off starts

Existing fixes

The symptom is reported in #32296. This cause is not reported there. None of the open fixes removes the echo:

Open fix	What it does	This case
#33859	Ignores an empty task-notification result in the same check	❌ Echo still counts
#32508	A hand-off keeps a busy session instead of refusing	❌ Echo still counts; only the refusal is hidden
Branch mika/queue-busy-switch from #32296	Counts root frames after the last buffered result	❌ The echo is such a frame

From reading their code, not from running those branches.

Change

In ClaudeAdapterV2.ts, a replayed local-command echo that arrives while no turn is active is dropped instead of buffered. Frames inside a turn are handled as before.

Other providers

Only Claude is affected. The others start a wake on an explicit turn-start event, not on any frame that arrives between turns:

Adapter	Answer to a live model change	What starts a wake between turns	Affected
Claude	user echo frame	Any root user, assistant or result frame	❌ Yes
ACP (Grok, Copilot, Antigravity, Kiro)	config_option_update or current_mode_update	Agent output, user_message, state running	✅ No
Pi	response	agent_start	✅ No
Muse	Request reply	turn/started	✅ No
Codex, OpenCode	—	No frame buffer; tracked commands, tools and subagents	✅ No

From reading each adapter, not from running the providers.

Scope and approval

Small focused fix of an obvious bug: a thread with nothing running cannot switch provider. One cause, one adapter, no change to the guard's policy or to any default. No triaged issue; refs #32296, which stays open because its other stale-state cases are not addressed.

Verification

Before is ClaudeAdapterV2.ts from main with this PR's test:

BEFORE
 × does not count the echo of a live model switch as background work 107ms
      Tests  1 failed | 408 skipped (409)

AFTER
 ✓ does not count the echo of a live model switch as background work 90ms
      Tests  1 passed | 408 skipped (409)

The test answers setModel with the echo, as the CLI does, and runs a turn on the new model. It also checks that a root user frame that is not an echo still counts; widening the fix to any user frame fails that assertion.

From the incident (a fork build from 2026-11-06, Windows, Claude Code 2.1.316, UTC):

16:22:39.087 IN  result                     turn 1 ends
16:24:41.210 IN  user  "<local-command-stdout>Set model to `claude-opus-5-5`</local-command-stdout>"
16:24:41.211 OUT query.set_model claude-opus-5-5
16:24:41.305     prompt.offer               turn 2 starts
16:24:44.761 IN  result                     turn 2 ends
16:25:07, 16:25:20, 16:25:56                send to another provider refused
16:34:04.350     Force stop                 session released

The log has no task or subagent frames. All 6 live model switches in local logs produced this echo, each just before the CLI confirmed the switch.

vp run check:changed: static checks pass. Its tests: 409 passed, 1 skipped, 1 failed. The failure is native fork > forks a session from its original directory after the workspace root changes, a Windows path assertion this change does not touch; it failed the same way on unmodified main at 60efd7c869. The app with a real Claude turn, the full suites and the build were not run. Node 24.4.1, not the pinned 26.12.1.

Written with Claude Fable 5.2 in T3 Code.

🤖 Generated with Claude Code

[macroscopeapp]

Approvability

Verdict: Approved at 6d57859

Macroscope's review found this PR approvable — This prevents idle Claude model-change echoes from being mistaken for background work that blocks provider switching. The filter is narrowly scoped, leaving active turns and genuine background-work handling unchanged.

^{You can add or adjust custom eligibility rules. Learn more.}

[coderabbitai]

No actionable comments were generated in the recent review.

Walkthrough

ClaudeAdapterV2 now drops replayed local-command echoes when no turn context exists. The test harness can supply SDK messages during a model change. A test checks that replayed echoes do not create pending background work or trigger continuation, while a non-replay frame does.

Changes: Claude local-command echo handling

Layer / File(s)	Summary
Filter idle local-command echoes apps/server/src/orchestration-v2/Adapters/ClaudeAdapterV2.ts, apps/server/src/orchestration-v2/Adapters/ClaudeAdapterV2.test.ts	The adapter recognizes replayed user frames whose string content begins with <local-command-stdout> and drops them when no turn context exists. The test harness supplies SDK messages during model changes. The test checks that replayed echoes do not count as background work, while a non-replay frame does.

Estimated code review effort: 2 (Simple) | ~10 minutes

Change: Bug fix

Suggested reviewers: juliusmarminge

Merge Risk: Minimal · up to a51ab

This change stops a replayed model-switch echo from making a finished thread look busy, so a later provider switch is no longer blocked. The change is small, targeted and covered by a regression test, and no merge-blocking risk was identified.

Pre-merge checks: 4

Check name	Status	Explanation
Title check		The title names the main change: a Claude model switch no longer blocks a later provider switch. The raw summary and PR objectives confirm the change drops replayed local-command echoes that were wron…
Description check		The description follows the repository template. It covers Problem (the symptom and root cause of the refused provider switch), Change (dropping replayed local-command echoes with no active turn in Cl…
Linked Issues check		Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check		Check skipped because no linked issues were found for this pull request.

Full details: Title check

Explanation

The title names the main change: a Claude model switch no longer blocks a later provider switch. The raw summary and PR objectives confirm the change drops replayed local-command echoes that were wrongly counted as background work. The title is specific, follows the conventional commit format from the template, and matches the changeset.

Full details: Description check

Explanation

The description follows the repository template. It covers Problem (the symptom and root cause of the refused provider switch), Change (dropping replayed local-command echoes with no active turn in ClaudeAdapterV2.ts), Scope (a small bug fix, with a reference to issue #32296 and an explanation for why no triaged issue is linked), and Verification (before/after test output, incident logs, and a note on the unrelated Windows test failure). The author also states what was not checked. The template's optional agent attribution line is present. The description is detailed and complete.

Finishing Touches

Generate unit tests (beta)

• Create a new PR

• Autofix · Keep fixing CodeRabbit findings and required CI, and resolving merge conflicts

Recent review info

Run configuration

• Source mode: Auto
• Repository: pingdotgg/t3code
• Branch: main
• File: .coderabbit.config.ts
• Commit: 35cc772
• Layers: Repository TS config
• Review profile: CHILL
• Plan: Advanced
• Run ID: bb0ae135-1636-4dee-903f-cdf51ce600ec

Commits

Reviewing files that changed from the base of the PR and between 70b1406 and a51ab6b.

Files selected for processing: 2

• apps/server/src/orchestration-v2/Adapters/ClaudeAdapterV2.test.ts
• apps/server/src/orchestration-v2/Adapters/ClaudeAdapterV2.ts

Included review availability: This review used your included allowance. Your plan provides up to 10 included reviews per hour; 9 remain after this review.

[github-actions]

This PR conflicts with main. Rebase it or merge main into it. If it still conflicts after 7 days with no activity, it will be closed automatically.

See the conflict window.

[juliusmarminge]

Evidence

Real web client, Chromium, 1280×800, light theme; separate fresh databases and real providers. Steps: Haiku 5.5 Medium → send one prompt → completed reply; Sonnet 5.5 High → send two prompt → completed reply; Codex GPT-6-Luna Medium → send three prompt.

Before	After
35cc7724c5	a51ab6b5a9
Before recording	After recording

Base also refused a retry more than three minutes after Sonnet completed, with no Stop button available. Head completed the same handoff and returned three.

Browser driver sequence.