fix(server): ACP v2 idle errors fail the turn#23217

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.

• Codex decoded thread snapshot: 108.5 KiB
• Claude decoded thread snapshot: 108.8 KiB

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• Repository: pingdotgg/t3code
• Branch: fix/issue-21219
• File: .coderabbit.config.ts
• Commit: f9c17f6
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Reviewing files that changed from the base of the PR and between 3ae498cbdd04ab047889afa792dcba0748f810e6 and f9c17f6f97480643c60af0463283374e969783e8.

📒 Files selected for processing: 2

• apps/server/src/orchestration-v2/Adapters/AcpRegistryAdapterV2.test.ts
• packages/provider-acp/src/server/adapter.ts

💤 Files with no reviewable changes: 1

• apps/server/src/orchestration-v2/Adapters/AcpRegistryAdapterV2.test.ts

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The ACP client now includes prompt errors in prompt responses. The provider adapter maps those errors to provider failures and finalizes affected turns as failed. Tests cover error payloads, a subsequent prompt, and failed-turn terminalization.

Changes: ACP Prompt Error Settlement

Layer / File(s)	Summary
Preserve ACP prompt errors packages/effect-acp/src/compat.ts, packages/effect-acp/src/client.ts	PromptResponse now has an optional nullable error field. The client copies an error from an idle session update into the response when present.
Map prompt errors to failed turns packages/provider-acp/src/server/adapter.ts, apps/server/src/orchestration-v2/Adapters/AcpRegistryAdapterV2.test.ts	The adapter maps ACP prompt errors through idleFailure and finalizes responses with stopReason === "error" as failed turns. Tests cover errors with and without payloads, a subsequent prompt with a different provider-turn ID, and one-time failed-turn terminalization.

Priority: ➖ Normal

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

Change: Bug fix

Sequence Diagram(s)

mermaid

1	sequenceDiagram
2	participant ACPUpdate
3	participant EffectAcpClient
4	participant ProviderAcpAdapter
5	participant ProviderTurn
6	ACPUpdate->>EffectAcpClient: idle update with optional error
7	EffectAcpClient->>ProviderAcpAdapter: PromptResponse containing error
8	ProviderAcpAdapter->>ProviderTurn: finalize turn as failed

Possibly related issues

• pingdotgg/t3code#16010: The adapter maps explicit ACP error stops to provider failures and records the turn as failed.

Suggested reviewers: stienswout

An ACP idle error can leave stale tool activity after the turn fails, and later Stop cannot clean it up. Resolve this before merging.

Check name	Status	Explanation
Title check	Passed	The title clearly and concisely describes the main change: ACP v2 idle errors now fail the server turn.
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.
Description check	Passed	The pull request includes all required sections: Problem, Change, Scope and approval, and Verification. It explains the reproduced failure, implementation, issue and approval context, focused test res…

Full details: Description check

Explanation

The pull request includes all required sections: Problem, Change, Scope and approval, and Verification. It explains the reproduced failure, implementation, issue and approval context, focused test results, limitations, runtime evidence, and agent and harness details.

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