fix(acp): bridge question prompts via extMethod

[Jayl1n]

Issue for this PR

Closes #17920. Also addresses #13752.

Type of change

• Bug fix

What does this PR do?

In ACP mode the question tool hangs forever: question.asked is published, a Deferred waits for the answer, but nothing forwards it to the ACP client, so the tool blocks indefinitely (#17920).

This adds an ACP bridge for question.asked, gated behind a client capability so existing clients keep their current behavior. When OPENCODE_ENABLE_QUESTION_TOOL=1 is set and the client advertises clientCapabilities._meta["opencode/question"] at initialize, the question request is forwarded over the ACP extension method opencode/question (connection.extMethod), and the response is mapped back to sdk.question.reply / sdk.question.reject. If the client declines, throws, or doesn't advertise the capability, the question is rejected so the agent isn't left waiting.

The handler mirrors the existing permission.ts Handler (per-session serialization via a promise queue), wired into ACPEvent.Subscription. The capability is parsed in ACPService.initialize via setQuestionEnabled.

Note: this is a port of #20017, which was written against the old monolithic agent.ts before the ACP layer was split into service.ts / event.ts / permission.ts. The original PR also wrote process.env.OPENCODE_ENABLE_QUESTION_TOOL inside initialize() to register the tool at runtime — that no longer works because the flag is now an Effect RuntimeFlags value snapshotted once at boot when the tool registry is built, so registering the question tool still requires the env var before server start (documented in the new acp/README.md).

Files:

• src/acp/question.ts (new) — Handler, mirrors permission.ts
• src/acp/event.ts — Connection gains extMethod; Subscription owns the handler + setQuestionEnabled
• src/acp/service.ts — initialize parses the capability
• src/acp/README.md (new) — capability contract
• test/acp/question.test.ts (new) — reply / reject / no-capability / extMethod-throws

How did you verify your code works?

• bun typecheck (run from packages/opencode)
• bun test test/acp/question.test.ts test/acp/permission.test.ts test/acp/event.test.ts — 26 pass / 0 fail

A reviewer can reproduce the fix by enabling the tool against an ACP client that advertises the capability:

OPENCODE_ENABLE_QUESTION_TOOL=1 ./packages/opencode/dist/opencode-darwin-arm64/bin/opencode acp

Screenshots / recordings

N/A (no UI changes)

Checklist

• I have tested my changes locally
• I have not included unrelated changes in this PR

[github-actions]

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[github-actions]

The following comment was made by an LLM, it may be inaccurate:

Potential Related PR Found:

• fix: support ACP question prompts via extMethod #20017 — "fix: support ACP question prompts via extMethod"
  • fix: support ACP question prompts via extMethod #20017
  • Relationship: This is the original PR that the current PR (fix(acp): bridge question prompts via extMethod #33482) explicitly references. PR fix(acp): bridge question prompts via extMethod #33482 is a re-implementation for the refactored ACP layer rather than a cherry-pick. The original fix: support ACP question prompts via extMethod #20017 was authored against the old monolithic agent.ts, while fix(acp): bridge question prompts via extMethod #33482 ports it to the current architecture with the new service.ts/event.ts/permission.ts handler pattern. They address the same feature but on different codebase versions.

No other duplicate or conflicting open PRs found.

[github-actions]

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