fix(server): open a new OpenCode turn after the provider goes idle

[jmfrank63]

What Changed

sendTurn no longer decides steer-vs-new-turn from the cached activeTurnId alone. Before reusing it, the adapter confirms the native session status — but only where an idle reading is actually authoritative for that turn.

An idle reading is not authoritative when idle evidence is deliberately withheld (prompt admission, post-interruption, or pending reconciliation each mean a known-stale idle is in flight and the prompt is a genuine mid-turn steer), nor before OpenCode has reported the turn busy, since it then describes the state before the turn started rather than after it ended. An unavailable or undecodable status keeps the previous behavior: never guess idle.

Two follow-on details the change needs to be correct:

• Completing a turn from the preflight leaves the native idle it stood in for still in flight, so idle reconciliation is armed. The next idle is checked against live status instead of trusted, and retires the turn it belongs to rather than the turn the follow-up just opened.
• The status request is itself a suspension point, so activeTurnId is re-read after it rather than trusting the id captured before it — the event pump can retire the turn while the request is in flight, which is the same race in a narrower window.

Two deterministic regression tests cover both orderings: the idle event arriving before the follow-up, and the idle event landing during the preflight. Both were verified to fail against the unfixed adapter with the reported symptom (the follow-up reusing the finished turn's id).

Why

Fixes #10973.

After an OpenCode task finished and the thread went idle, the first follow-up message was ignored. activeTurnId is cleared asynchronously by the event pump once native idle evidence is processed, so a prompt submitted during that gap reused the finished turn's id. That skipped turn.started and accrued the new work's tokens to the previous turn — from the user's side, the message looked like it did nothing.

The narrow fix is to confirm the provider's real status before trusting a cached turn id, while leaving every case where the cached id is legitimately still live untouched. In particular, the existing coverage for a mid-turn steer racing a stale idle status is unchanged and still green: that path is classified as withheld idle evidence and skips the status read entirely.

Verification: focused adapter suite 112/112 (run repeatedly for stability), all eight OpenCode test files 195/195, apps/server typecheck clean, targeted lint and format clean.

Checklist

• This PR is small and focused
• I explained what changed and why
• I included before/after screenshots for any UI changes — N/A, server-only change with no UI surface
• I included a video for animation/interaction changes — N/A

🤖 Generated with Claude Code

Summary by CodeRabbit

• Bug Fixes
  • Improved handling of concurrent follow-up turns to prevent completed turns from being incorrectly reused.
  • Ensured stale or delayed idle-status events do not end newer active turns.
  • Improved recovery when status updates race with turn submission, preserving the correct active turn and running state.

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ℹ️ Recent review info

⚙️ Run configuration

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Run ID: 6cad2ede-37b9-4cda-9850-1981cd362c36

📥 Commits

Reviewing files that changed from the base of the PR and between d29c56a and 0596dc4.

📒 Files selected for processing (2)

• apps/server/src/provider/Layers/OpenCodeAdapter.test.ts
• apps/server/src/provider/Layers/OpenCodeAdapter.ts

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📝 Walkthrough

Walkthrough

The OpenCode adapter now tracks native busy status before reusing an active turn. It performs a status preflight when required, completes stale turns, and preserves newer turns across delayed idle events. Two regression tests cover these concurrency races.

Changes

OpenCode turn boundary

Layer / File(s)	Summary
Native busy-state tracking apps/server/src/provider/Layers/OpenCodeAdapter.ts	The session context records native busy or retry status. The flag resets when turns complete, fail, are interrupted, encounter errors, or start fresh.
Guarded steering and race coverage apps/server/src/provider/Layers/OpenCodeAdapter.ts, apps/server/src/provider/Layers/OpenCodeAdapter.test.ts	sendTurn checks native status before reusing a busy active turn. Tests cover delayed idle events and suspended status preflight.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Severity of issue fixed: Low

Sequence Diagram(s)

sequenceDiagram
  participant FollowUpCaller
  participant sendTurn
  participant OpenCode
  participant TurnState
  FollowUpCaller->>sendTurn: submit follow-up
  sendTurn->>OpenCode: request session.status
  OpenCode-->>sendTurn: idle or missing status
  sendTurn->>TurnState: complete stale active turn
  sendTurn->>OpenCode: start distinct follow-up turn

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Suggested reviewers: t3dotgg, maria-rcks, juliusmarminge

Merge Risk: ⚪ Minimal · up to 0596d

This change separates completed OpenCode follow-up turns from legitimate mid-turn steering by checking native status before reusing cached turn IDs. Focused tests and validation checks pass, with no concrete current-head correctness or availability issue identified.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 1 functions across 2 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 summarizes the primary change: opening a new OpenCode turn after the provider becomes idle.
Description check	✅ Passed	The description includes complete What Changed, Why, UI Changes, and Checklist sections. It explains the fix, preserves steering behavior, describes regression coverage, and reports verification resul…
Linked Issues check	✅ Passed	The implementation directly addresses issue #10973. It prevents completed turns from being reused, preserves valid mid-turn steering, handles status and event races, and adds regression tests for both…
Out of Scope Changes check	✅ Passed	The changes are limited to the OpenCode adapter and focused concurrency regression tests. They support the linked issue and do not introduce unrelated functionality.

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