fix(server): settle every OpenCode subagent call one report answers

[nkoynov]

Problem

When the model calls OpenCode's subagent tool again with the session id of a subagent that is still running (to steer it), OpenCode steers the child and joins its running job, so it sends one report for both calls. onReport settles only the first call bound to that child. The second card stays "Running" forever, and the parent's provider thread keeps it in pendingBackgroundTasks, so the thread looks like it's still waiting on background work until T3 restarts (which then shows it as cancelled).

A resumed subagent that had already finished is fine: its new run gets its own report.

Change

• A call that attaches to a child whose session has a running turn joins that run (SubagentCall.joined). onReport settles the first call bound to the child plus every call that joined it. A call to a child that already finished starts a new run and waits for that run's report, even if the old report arrives after it.
• A call whose tool returns status: "running" without background: true (a steer that joined a backgrounded run) now counts as background, which is what the field's doc says. Before, the turn's end settled it empty.

Verification

• Three tests in OpenCode2AdapterV2.test.ts: a background steer (both cards complete with the report text and pendingBackgroundTasks empties), a steer without background (the card waits for the report instead of closing at the turn's end), and a resume of a finished child whose old report arrives late (it only settles the old call). The first two fail on main; the third passes on both and guards the run boundary.
• Rebased onto main @ b707eeb on 2026-10-09 (clean; the adapter change follows packages/provider-opencode/src/server/v2/adapter.ts, the tests stay in OpenCode2AdapterV2.test.ts); vp test run on OpenCode2AdapterV2.test.ts and OpenCode2OrchestratorV2.integration.test.ts: 100/100, lint, fmt and typecheck (vp run --filter t3 typecheck and provider-opencode's tsc) pass.
• Live on nightly 0.0.46-nightly.20261008.2801 with OpenCode 2.0.24 and cursor/claude-opus-5-5-1m: launch A and B in the background, steer A while it sleeps, let both finish. A and B completed and "Steer A" stayed running, with pendingBackgroundTasks still listing it. That matches our host's state DB over the past week: every steer of a running child left one stuck card, and nothing else did. I haven't run this branch live. With a local workaround on 2801 that settles the extra call the same way (it adds a cancelled copy of the report to the event stream), all three completed, A and its steer at the same moment.

Side note: the test file's event() helper stamps every event with durable version 1, but session.tool.success is version 2 in @opencode/schema, so success frames built with it are dropped. The new tests build theirs with version 2; I left the existing ones alone.

Model: Claude Opus 5.5 (1M). Harness: OpenCode in T3 Code.

[macroscopeapp]

Approvability

Verdict: Approved at 5b100b4

Macroscope's review found this PR approvable — This is a localized OpenCode subagent lifecycle bug fix that prevents joined calls from remaining stuck and preserves correct report association across successive runs. Production changes are confined to the existing adapter, with targeted regression tests covering the affected timing cases.

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📒 Files selected for processing (1)

• apps/server/src/orchestration-v2/Adapters/OpenCode2AdapterV2.test.ts

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

• apps/server/src/orchestration-v2/Adapters/OpenCode2AdapterV2.test.ts

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📝 Walkthrough

Walkthrough

The adapter now records when a subagent call joins an active child run. When the run reports, the adapter applies its outcome to the matching call and calls linked to it. Replay tests cover multiple join scenarios.

Changes

OpenCode 2 subagent call joining

Layer / File(s)	Summary
Track calls joining an active run packages/provider-opencode/src/server/v2/adapter.ts	Subagent calls record a reference to an eligible call when attaching to an active child session.
Settle joined calls from child reports packages/provider-opencode/src/server/v2/adapter.ts, apps/server/src/orchestration-v2/Adapters/OpenCode2AdapterV2.test.ts	Running tool results update background call state. A child report settles the matching call and linked calls with the report outcome. Replay tests cover multiple calls joining one run, a foreground call joining a background run, and a call made after one run ends but before its report arrives.

Priority: ➖ Normal

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

Change: Bug fix

Sequence Diagram(s)

sequenceDiagram
  participant OpenCode2Adapter
  participant SubagentCall
  participant ChildSessionReport
  OpenCode2Adapter->>SubagentCall: records joined-call reference
  ChildSessionReport->>OpenCode2Adapter: provides child outcome
  OpenCode2Adapter->>SubagentCall: applies report status to linked calls

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Merge Risk

Merge Risk: ⚪ Minimal · up to 62189

The change settles every OpenCode subagent call that one report answers. No actionable merge-blocking risk is evident from the supplied review context.

Security Architecture Review

Security architecture risk: 🔵 Low · up to 9dce1

Calls sharing an active child execution now complete together without gaining new permissions or exposing a new external interface. Remaining uncertainty concerns report ordering when successive runs reuse the same child session.

Retained concerns
No architecture-level concerns identified.

Security review details

Security Blast Radius

• inferred — The added settlement fanout reaches calls explicitly linked within one parent's outstanding-call map. The changed path affects projected results, terminal statuses, and background-work tracking; it does not add permission grants, credentials, or command-execution authority.

Trust Boundaries and Controls

• inferred — Successive runs still depend on correct report ordering because settlement uses session identity, not execution identity. This dependency predates the PR. The new regression test establishes separation when the first report is handled first, but does not establish behavior under reordered reports or cross-parent session reuse.

Resilience and Maintainability Implications

• observed — A Stop that cannot reach a child keeps its calls tracked for another attempt rather than falsely clearing outstanding work. Reconciliation interrupts calls whose child is no longer active, providing recovery when report events are lost.

Hardening Proposals

• proposed — Document the producer's successive-run ordering and session-ownership guarantees. If ordering is not guaranteed, correlate reports with execution identity rather than session identity alone. This is a hardening proposal, not a verified introduced vulnerability.

🚥 Pre-merge checks | ✅ 3 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Description check		The description clearly covers the problem, implementation, affected behavior, tests, manual reproduction, and limitations. It omits the required Scope and approval section, including an issue or appr…	Add a Scope and approval section. Include the triaged issue or maintainer approval with the relevant comment, or explain why this focused bug fix qualifies without prior discussion.

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check		The title clearly and concisely describes the main fix: settling all OpenCode subagent calls answered by one report.
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: Description check

Explanation

The description clearly covers the problem, implementation, affected behavior, tests, manual reproduction, and limitations. It omits the required Scope and approval section, including an issue or approval link or a rationale for treating this as an obvious focused fix.

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Inline comments:
Review comments at
@apps/server/src/orchestration-v2/Adapters/OpenCode2AdapterV2.test.ts:
- Around line 1057-1058: Update the test’s watchCalls handling to capture a
snapshot of the call state when it observes `${CHILD}:turn:2`, then assert
against that snapshot instead of the live `watch.calls` map after `watch.until`
resumes.

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📒 Files selected for processing (2)

• apps/server/src/orchestration-v2/Adapters/OpenCode2AdapterV2.test.ts
• apps/server/src/orchestration-v2/Adapters/OpenCode2AdapterV2.ts

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