fix(server): a background Claude subagent no longer looks frozen once its parent goes idle

[yordis]

• When a parent turn ended while its Claude subagent kept running, the subagent's progress updates were dropped, so its card stayed frozen on whatever it showed at that moment, sometimes for most of an hour of active work.
• A user watching a busy subagent could not tell it apart from a stuck one, which pushes them to interrupt work that was actually progressing.
• The child thread view still shows a generic "Thinking" row until the subagent finishes; that is a separate follow-up.

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[cursor]

PR Summary

Medium Risk
Changes orchestration event routing and turn-item projection for background subagents; behavior is scoped to idle-root task_progress but affects live UI state users rely on to judge whether work is stuck.

Overview
Background Claude subagents (run_in_background) can keep emitting task_progress after the parent turn settles; those frames were effectively ignored, so the subagent card and its turn item stayed stuck on the last progress shown before the root went idle.

ClaudeAdapterV2 now pins turn attribution on each active subagent (turnItemProviderThreadId / turnItemProviderTurnId) when the card is created or reopened, so updates do not depend on a live turn context. When there is no active turn and a task_progress arrives, a new path applyClaudeSubagentProgressWithoutActiveTurn updates the session subagent registry and emits subagent.updated plus turn_item.updated (still skipping settled or non-running tasks). That path is wired in the idle-root message handler instead of treating progress like wake evidence via bufferWakeMessage.

The claude_background_subagent_after_root fixture now asserts the latest idle-window progress is reflected on both the subagent and the subagent turn item mobile reads.

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📥 Commits

Reviewing files that changed from the base of the PR and between 25a4fce and 62bacd1.

📒 Files selected for processing (2)

• apps/server/src/orchestration-v2/Adapters/ClaudeAdapterV2.ts
• apps/server/src/orchestration-v2/testkit/fixtures/claude_background_subagent_after_root/output.ts

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📝 Walkthrough

Walkthrough

The Claude adapter now applies idle task_progress frames to running subagents. It retains provider thread and turn attribution for turn-item updates. The fixture checks that the subagent and its turn item report the latest progress.

Changes

Idle Subagent Progress

Layer / File(s)	Summary
Retain subagent provider attribution apps/server/src/orchestration-v2/Adapters/ClaudeAdapterV2.ts	Subagents retain their provider thread and turn attribution. Reopening a terminal subagent as running updates that attribution.
Apply idle progress to running subagents apps/server/src/orchestration-v2/Adapters/ClaudeAdapterV2.ts, apps/server/src/orchestration-v2/testkit/fixtures/claude_background_subagent_after_root/output.ts	Idle task_progress frames update running subagents and emit subagent and turn-item updates using stored attribution. The fixture checks that both report the latest progress.

Priority: ⬇️ Low

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

Change: Bug fix

Suggested reviewers: juliusmarminge

Merge Risk: ⚪ Minimal · up to 62bac

The idle subagent progress change is mergeable after normal checks; no actionable issue remains.

🚥 Pre-merge checks | ✅ 3 | ❌ 2

❌ Failed checks (2 warnings)

Check name	Status	Explanation	Resolution
Description check	⚠️ Warning	The description explains the problem, but it does not include the required Change, Scope and approval, or Verification sections. It also omits the Problem heading.	Add the required sections. Explain how the change fixes the issue, provide the linked issue or maintainer approval (or explain why this focused bug fix needs no prior approval), and describe the focused verification performed and its result…
Docstring Coverage	⚠️ Warning	Docstring coverage is 50.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 2 functions across 2 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly describes the main change: keeping a background Claude subagent’s progress visible after its parent goes idle.
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.

Full details: Description check

Resolution

Add the required sections. Explain how the change fixes the issue, provide the linked issue or maintainer approval (or explain why this focused bug fix needs no prior approval), and describe the focused verification performed and its results. Include the Problem heading for consistency with the template.

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Thread transfer impact

✅ Thread transfer remains within every enforced ceiling.

Provider	Metric	Main baseline	This PR	Impact	PR ceiling
Codex	Total thread wire	4.9 KiB	4.9 KiB	0 B (0.0%)	6.8 KiB	✅
Codex	Thread snapshot wire	3.7 KiB	3.7 KiB	0 B (0.0%)	4.9 KiB	✅
Codex	Live turn WebSocket wire	1.2 KiB	1.2 KiB	0 B (0.0%)	2.0 KiB	✅
Codex	Live turn WebSocket decoded	20.4 KiB	20.4 KiB	0 B (0.0%)	29.3 KiB	✅
Codex	Live turn messages	2	2	0 (0.0%)	8	✅
Claude	Total thread wire	4.9 KiB	4.9 KiB	0 B (0.0%)	6.8 KiB	✅
Claude	Thread snapshot wire	3.7 KiB	3.7 KiB	0 B (0.0%)	4.9 KiB	✅
Claude	Live turn WebSocket wire	1.2 KiB	1.2 KiB	0 B (0.0%)	2.0 KiB	✅
Claude	Live turn WebSocket decoded	20.8 KiB	20.8 KiB	0 B (0.0%)	29.3 KiB	✅
Claude	Live turn messages	2	2	0 (0.0%)	8	✅

Baseline: 25a4fce · PR result: 62bacd1 · Source CI: success

Scenario and decoded snapshot size

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: 106.1 KiB
• Claude decoded thread snapshot: 106.4 KiB

Updated in place by a trusted workflow. PR artifacts are strictly validated and never executed.