fix(orchestration): resume continuations after planned worktree handoffs

[jakeleventhal]

Planned worktree handoffs currently end the old provider stream as a failure, which holds the continuation. Persisting the binding and continuation separately also lets a delegated child publish its result before the follow-up is queued.

The handoff now commits the workspace binding, continuation, checkpoint scope, and detach intent together. A typed workspace-change signal interrupts only the moving thread, including before its first provider turn. Shared-session siblings stay alive; open tools finish as interrupted. Normal finalization starts the continuation in the destination worktree. Explicit Stop and real provider failures still hold queued input.

Maintainer rebuild of @jakeleventhal’s #15203, preserving the author’s commits. @timvdhoorn identified the unfinished root-tool issue retained in this fix. The original 11 added executable test cases were reduced to three behavior tests; subscription ownership reuses the existing subscriber map.

Verification:

• Four focused files: 185 original cases → 177, all passing (current main has 174). Atomic-persistence and detach-reason revert controls fail by assertion. The original shared-session path also fails the retained integration assertion.
• Both existing exclusive/shared handoff cases also suspend startup after the event consumer forks, then prove the real outbox cannot claim the detach until startup finishes. This addresses the reported startup race without adding a production gate.
• Two fresh whole-PR review rounds from both reviewers found no remaining actionable issues.
• Existing provider-error, Stop, startup and shutdown queue controls pass. Independent review also ran the complete adjacent queue/control and thread deletion/settlement suites.
• Scoped server, provider-core and contracts typechecks, lint, formatting and diff checks pass.
• Full isolated backend with actual Codex: a parent and delegated child shared one provider session; the child handoff interrupted its old run/tool, automatically resumed, wrote the destination cwd, and checkpointed the new file. The parent completed after exactly one child-result transfer. Replaying the accepted handoff command kept two runs and five messages unchanged.
• Headless backend before/after proof.

Current-head CI passes, including the full web rerun. Two earlier attempts failed the same unchanged highlighting assertion; its focused three browser cases pass on both head and base. Macroscope Correctness passes; Approvability remains neutral pending human review of the lifecycle change.

This is backend lifecycle behavior with no rendering change. Live proof covers Codex on headless Linux. Exclusive-session behavior has deterministic integration coverage; live Claude, Cursor, Grok, OpenCode, Antigravity, macOS, Windows, iOS, Android and Electron desktop remain unverified. The optional continuation command field adds no client entry point or permission.

Implementation and live verification: GPT-6.1 Sol; tests: GPT-6 Astra; adversarial reviews: Claude Opus 5.5 and GPT-6 Sol. Harness: T3 Code with Codex and Claude.

[macroscopeapp]

Approvability

Verdict: Needs Human Approval

Macroscope's review found this PR requires human approval — The PR substantially changes production orchestration lifecycle behavior: worktree handoffs now atomically enqueue continuations and selectively interrupt provider sessions, tools, and runs before resuming in the new workspace. Its additive contracts and focused tests reduce risk, but the cross-component state and event-flow changes warrant human review.

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📝 Walkthrough

📝 Walkthrough

Walkthrough

Worktree handoffs can include a continuation in the metadata update. Workspace-change detachments now produce a typed error that interrupts the matching run. Tests and documentation cover continuation timing and queued-input behavior.

Changes

Worktree handoff and continuation

Layer / File(s)	Summary
Dispatch the binding and continuation packages/contracts/src/orchestrationV2.ts, apps/server/src/orchestration-v2/Orchestrator.ts, apps/server/src/mcp/WorktreeMcpService.ts, apps/server/src/mcp/WorktreeMcpService.test.ts	The metadata update accepts and validates a continuation and dispatches it with the worktree binding. The handoff reports delivery from stored events instead of sending a separate message.
Propagate planned detach interruptions apps/server/src/orchestration-v2/EffectOutbox.ts, apps/server/src/orchestration-v2/EffectWorker.ts, apps/server/src/orchestration-v2/ProviderAdapter.ts, apps/server/src/orchestration-v2/ProviderSessionManager.ts, apps/server/src/orchestration-v2/RunExecutionService.ts, apps/server/src/orchestration-v2/RunExecutionService.test.ts	Workspace-change detach effects carry a reason. The session manager emits a typed detach error, and run execution treats a matching error as an interruption with a workspace-change message.
Verify handoff and queued-input behavior apps/server/src/orchestration-v2/SelectionRestart.integration.test.ts, docs/internals/overview.md, docs/user/composer.md	Integration tests cover handoff timing, delegated continuations, and queued messages after provider failure or explicit Stop. The documentation describes automatic continuation and queue resumption.

Priority: ➖ Normal

Estimated code review effort: 4 (Complex) | ~60 minutes

Change: Bug fix

Sequence Diagram(s)

sequenceDiagram
  participant WorktreeMcpService
  participant Orchestrator
  participant EffectWorker
  participant ProviderSessionManager
  participant RunExecutionService
  WorktreeMcpService->>Orchestrator: Dispatch binding with continuation
  Orchestrator->>Orchestrator: Apply binding and dispatch queued continuation
  Orchestrator->>EffectWorker: Record workspace-change detach effect
  EffectWorker->>ProviderSessionManager: Detach session with workspace_changed reason
  ProviderSessionManager->>RunExecutionService: Publish ProviderAdapterSessionDetached
  RunExecutionService->>RunExecutionService: Finalize matching run as interrupted

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Suggested reviewers: juliusmarminge

Merge Risk: 🟡 Moderate · up to 55e45

A worktree handoff can leave the old run waiting indefinitely in shared provider sessions. A queued continuation can also record checkpoints against the previous worktree. Both should be fixed before merging.

Security Architecture Review

Security architecture risk: 🔵 Low · up to 55e45

The handoff now records its follow-up message together with the workspace change and checks thread/session identity before resuming. No new access-control bypass was established, but shared-session recovery and rollback workspace selection remain incompletely verified.

Retained concerns
No architecture-level concerns identified.

Security review details

Security Blast Radius

• inferred — The reachable public operation requires authenticated environment-level orchestration authority and targets one thread per command. Repetition is not bounded to one thread by that scope check; project or tenant isolation beyond the environment boundary was not established by this review.

Trust Boundaries and Controls

• observed — Websocket upgrade authenticates the session, and RPC middleware requires orchestration-operate scope before command handling. The inspected revision comparison shows no change to these enforcement files.
• observed — The new public payload is converted into an agent/MCP message with no attachments and queued delivery. The previous handoff used the same agent/MCP provenance through sendToThread. The payload does not carry notification or delegated-completion fields, whose separate provenance controls remain enforced.

Resilience and Maintainability Implications

• observed — Queue scheduling refuses held queued input and retains recovery gating after non-validation provider failures. Focused integration tests cover planned handoff ordering, early exclusive-session detach, explicit Stop and provider-failure controls.
• observed — The new typed subscriber failure is sent when an exclusive session is released. Shared multi-thread sessions instead unload native threads without that signal. Codex unload requests thread unsubscribe; OpenCode2 unload returns without cleanup for active or background work. Equivalent terminalization, especially before native thread identity exists, remains unproven. The manager's shared unload branch predates this PR.

Pre-merge checks: 4 · 1

Failed checks: 1 warning

Check name	Status	Explanation	Resolution
Docstring Coverage		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 3 functions across 11 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

Passed checks: 4 passed

Check name	Status	Explanation
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.
Title check		The title is concise, specific, and accurately describes the primary change: resuming continuations after planned worktree handoffs.
Description check		The description is complete and relevant. It explains the problem, the implementation, scope and maintainer involvement, detailed verification results, limitations, and test ownership. It does not use…

Full details: Description check

Explanation

The description is complete and relevant. It explains the problem, the implementation, scope and maintainer involvement, detailed verification results, limitations, and test ownership. It does not use the exact template headings for Problem, Change, or Scope and approval, but the required information is present in the text.

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Actionable comments posted: 2

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Inline comments:
Review comments at @apps/server/src/orchestration-v2/Orchestrator.ts:
- Line 9549: Update the cwd fallback passed to dispatchMessage so
projection.thread.worktreePath takes precedence over
selectedProviderSession?.cwd when runtimePolicy.resolve provides no cwd; keep
process.cwd() as the final fallback so queued continuation checkpoints use the
current worktree.

Review comments at @apps/server/src/orchestration-v2/ProviderSessionManager.ts:
- Around line 2032-2034: Update the shared-session detach handling around
expectedDetach to send a ProviderAdapterSessionDetached signal to the subscriber
for input.threadId even when activeTurns is empty; do not fail subscribers
belonging to other attached threads.

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📥 Commits

Reviewing files that changed from the base of the PR and between 17801ba and 55e454a.

📒 Files selected for processing (4)

• apps/server/src/orchestration-v2/EffectWorker.ts
• apps/server/src/orchestration-v2/Orchestrator.ts
• apps/server/src/orchestration-v2/ProviderSessionManager.ts
• packages/contracts/src/orchestrationV2.ts

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[timvdhoorn]

Thanks for this PR. I've been running it locally (ported onto nightly 0.0.46-nightly.20261015.3158) and the continuation now starts after t3_worktree_handoff. I hit one leftover issue and wanted to share a fix.

Issue: the t3_worktree_handoff tool call stays running in the interrupted run, so the timeline keeps showing it as waiting. The planned detach ends the provider stream before the Claude adapter's finalizeActiveTurn → endToolCalls runs, and the synthesized terminal in RunExecutionService only covers the provider turn. I saw this on every handoff: three threads, each with the handoff call still running in an interrupted run.

Fix: keep track of the root turn's open items. When the planned detach happens, emit them as interrupted before the synthesized terminal, the same way the adapter handles a normal Stop. Subagent items are left out because the run-owned subagent cascade already ends them.

@@ -939,6 +939,11 @@ export const layer: Layer.Layer<
           const latestTurnItemOrdinal = yield* Ref.make(input.providerTurnOrdinal * 100);
           const latestProviderThread = yield* Ref.make(input.providerThread);
           const latestRootProviderTurn = yield* Ref.make<OrchestrationV2ProviderTurn | null>(null);
+          // Root items still open, so a planned detach can end the calls whose
+          // results the detached provider session will never report.
+          const openRootTurnItems = yield* Ref.make<ReadonlyMap<TurnItemId, OrchestrationV2TurnItem>>(
+            new Map(),
+          );
           const routeIdentity: ProviderEventRouteIdentity = {
             threadId: input.run.threadId,
             runId: input.run.id,
@@ -1277,7 +1282,18 @@ export const layer: Layer.Layer<
                             }
                           : state,
                       );
+                      const openItems = [...(yield* Ref.getAndSet(openRootTurnItems, new Map())).values()];
                       return Stream.fromIterable<ProviderAdapterV2Event>([
+                        ...openItems.map((turnItem) => ({
+                          type: "turn_item.updated" as const,
+                          driver: input.providerThread.driver,
+                          turnItem: {
+                            ...turnItem,
+                            status: "interrupted" as const,
+                            completedAt,
+                            updatedAt: completedAt,
+                          },
+                        })),
                         ...(providerTurn?.status === "running" || providerTurn?.status === "pending"
                           ? [
                               {
@@ -1378,6 +1394,18 @@ export const layer: Layer.Layer<
                   yield* Ref.update(latestTurnItemOrdinal, (current) =>
                     Math.max(current, event.turnItem.ordinal),
                   );
+                  const turnItem = event.turnItem;
+                  // Subagent rows end through the run-owned subagent cascade.
+                  if (turnItem.type !== "subagent") {
+                    const open = turnItem.status === "running" || turnItem.status === "pending";
+                    yield* Ref.update(openRootTurnItems, (items) => {
+                      if (!open && !items.has(turnItem.id)) return items;
+                      const next = new Map(items);
+                      if (open) next.set(turnItem.id, turnItem);
+                      else next.delete(turnItem.id);
+                      return next;
+                    });
+                  }
                 }
                 if (event.type === "turn.terminal") {
                   yield* Ref.set(terminalEvent, event);

Test (in RunExecutionService.test.ts): send a running root dynamic_tool item, then ProviderAdapterSessionDetached, and check that the item is ingested as interrupted. To see what gets ingested, the captureRootRunTermination helper now records the items passed to ingestNormalized in a separate ingested list. The test fails without the change and passes with it.

[jakeleventhal]

@timvdhoorn Thanks for the detailed report and proposed fix. You're right: the planned-detach path interrupted the provider turn without ending its open root tool items.

Fixed in 19f7ff9. It tracks pending/running root items and emits their interrupted updates before the synthesized terminal. Completed items are removed from tracking, and subagent items stay with the existing run-owned cascade.

Added regression coverage for pending and running tools, multiple open items, already-completed items, event ordering, and subagent cleanup without duplicate terminal updates. The two root-tool cases fail before the fix and pass after it. All 120 tests across RunExecutionService.test.ts, SelectionRestart.integration.test.ts, and WorktreeMcpService.test.ts pass; server typecheck, scoped lint, formatting, and git diff --check also pass. I haven't run a live Claude session.

Model and harness: GPT-6.1 Sol (HIGH), T3 Code through the Codex harness.

[juliusmarminge]

Taking over this one as maintainer for batch worktree-git-17. I will keep this PR and preserve your commits, reduce the regression and implementation scope, and fix the shared-session detach path before independent reviews. Atomic continuation persistence and real-provider verification remain acceptance gates. No merge is planned.

[juliusmarminge]

Final update: the third CI attempt on 833522786f passed, including Test Web and the aggregate Check. All latest Actions checks pass or are skipped, and Macroscope Correctness passes. The CI blocker above is cleared. Macroscope Approvability still requires human review; this PR remains unmerged.