fix(cli): a frozen claude turn is cancelled at its window, and the seat names that window by lilyshen0722 · Pull Request #3226 · Team-Commonly/commonly

lilyshen0722 · 2026-11-01T12:07:56Z

SRE's forced-stall walk on rivet (2026-11-01, cli 0.1.219) froze the seat's claude child with SIGSTOP as its turn began. The turn was cancelled 191 s later, and that was read as "the stall watchdog cancels about 60% later than its 120 s window".

Where the time went. Rivet's log names the watchdog that fired:

11:40:12.179Z spawning claude
11:43:23.549Z spawn credential revoked
11:43:24.066Z ... stalled ... claude produced no output in 180s (stuck: no model output inside the window)

180 s is the claude adapter's first-output watchdog, at its default window (COMMONLY_FIRST_OUTPUT_WINDOW_MS). The 120 s is stallMs in packages/seats/src/supervisor.js, that package's default. The CLI turns it off for claude (STALL_DEFAULTS_MS.claude = 0), and rivet's claude turns don't run supervised at all.
10 s is STALL_KILL_GRACE_MS. Claude handles SIGTERM, and a stopped process holds a signal it handles until it is continued. So the SIGTERM never ran, and SIGKILL came at the grace.
About 1 s is teardown.

Changes

The stall kill sends SIGCONT to the same process tree right after the SIGTERM, so a stopped turn acts on it at once. SIGKILL still lands at the grace for anything that ignores SIGTERM.
agent run logs the window a claude seat actually runs under: first-output watchdog ON for claude: a turn with no model output in 180000ms is killed (SIGTERM, then SIGKILL 10000ms later if it is still alive). The supervised boot line never prints for claude seats.
docs/cli/README.md lists COMMONLY_FIRST_OUTPUT_WINDOW_MS, and AX audit entry 90 records the misread.

Proof. A test freezes a real child: it handles SIGTERM, and is SIGSTOPped once its handler is installed. With a 1.5 s window and an 8 s grace it asserts the cancel lands before the window plus 2 s. Reverse check with the SIGCONT removed: red at 9577 ms, which is the window plus the grace, the same arithmetic as rivet's 191 s. Restored: green at 1517 ms. Boot-line tests cover on, a custom window and off, and that the line appears for claude only; dropping the log call turns them red. The existing signal-order test now expects SIGTERM, SIGCONT, SIGKILL.

Local: first-output-watchdog.test.mjs 36/36. The full cli suite is 2301 passed. The 3 failures are environmental on this Mac: the contract test needs backend deps this worktree lacks (ts-node), and the seatbelt hook smoke test trips on host git attributes. One review round (D218): a subagent review returned PASS with one should-fix, a startup race in the test window on a slow runner, plus two wording nits. All three are applied.

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https://claude.ai/code/session_015AKgpQ2pr6xRMhN5mcfoHF

…at names that window SRE's forced-stall walk froze rivet's claude child with SIGSTOP at turn start and read the 191 s cancel as a 120 s stall window running 60% late. Rivet's log names the watchdog that fired: "claude produced no output in 180s", the first-output watchdog at its default window. The 120 s was the seats supervisor's package default, which the CLI turns off for claude. The other 10 s was the kill grace: claude handles SIGTERM, and a stopped process holds a signal it handles until it is continued, so SIGKILL came at the grace. The stall kill now sends SIGCONT right after the SIGTERM, so a stopped turn acts on it at once. A claude seat logs the window it runs under at boot, docs/cli/README.md lists COMMONLY_FIRST_OUTPUT_WINDOW_MS, and AX audit entry 90 records the misread. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_015AKgpQ2pr6xRMhN5mcfoHF

coderabbitai · 2026-11-01T12:08:20Z

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cli/__tests__/first-output-watchdog.test.mjs

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Walkthrough

The Claude first-output watchdog now resumes a stalled process tree after SIGTERM and before the existing delayed SIGKILL. Claude run logs report the watchdog configuration. The CLI documentation describes its environment variable, default window, and disable value.

Changes: Claude first-output watchdog

Layer / File(s)	Summary
Watchdog cancellation sequence `cli/src/lib/adapters/claude.js`, `cli/__tests__/first-output-watchdog.test.mjs`	When the watchdog detects a stall, `runClaude` sends `SIGCONT` after `SIGTERM`. Tests cover the signal order, cancellation timing, and stopped processes in the process group.
Watchdog configuration reporting `cli/src/lib/first-output-watchdog.js`, `cli/src/commands/agent.js`, `cli/__tests__/first-output-watchdog.test.mjs`, `docs/cli/README.md`, `docs/development/agent-experience-audit.md`	`describeFirstOutputWatch` reports whether the watchdog is disabled or enabled with its configured window and termination sequence. Claude runs log the description. Tests and documentation cover the configuration and output.

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

Change: Bug fix

Merge Risk: Minimal · up to 833b6

Watchdog cancellation now attempts to resume stopped processes. The prior documentation and test-race concerns are addressed, with no merge-blocking risk identified.

Pre-merge checks: 4

Check name	Status	Explanation
Title check		The title clearly summarizes the main changes: timely cancellation of a frozen Claude turn and logging the watchdog window.
Description check		The description directly explains the cancellation delay, SIGCONT fix, watchdog logging, documentation updates, audit entry, and test evidence.
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.

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lilyshen0722

HEAD: 7224aa5 — GATE: PASS

One review round (D218), an in-session subagent review at this head.

Fix: SIGCONT goes to the same tree right after the stall SIGTERM, so a stopped child that handles SIGTERM acts on it at once. SIGKILL at the grace stays as the backstop, and a running child is unaffected.
Test: a real child is frozen after its SIGTERM handler is installed, and the cancel is asserted inside window + 2 s. The test is red without the fix (9577 ms = window + grace) and green with it (1517 ms).
Boot line: claude seats now log their real first-output window. Tests cover on, a custom value, off, and claude-only.
Applied from the review: the startup race in the test window, the comment wording, and the doc wording.
Lane (cli/): there is no version-line edit, and nothing else outside the adapter, the watchdog module, agent.js, the docs, and the test changes.

GATE: PASS

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Follow-up Comments

Qualify the claim that Claude’s supervised stall window is off.

304-304: Minor · Functional Correctness · Quick win

Qualify the claim that Claude’s supervised stall window is off.

The window is off by default. If a supervised Claude run sets COMMONLY_SUPERVISE_STALL_MS or COMMONLY_SUPERVISE_STALL_MS_CLAUDE above zero, the supervisor also has an active stall window. The current wording can lead an operator to tune only COMMONLY_FIRST_OUTPUT_WINDOW_MS while an earlier supervisor stall still cancels the turn. State the default and the override exception here and in audit entry 90. (raw.githubusercontent.com)

As per path instructions for docs/**, check factual claims about code against the repository at this head.

Open the source location
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Review comment at @docs/cli/README.md at line 304:
Update the COMMONLY_FIRST_OUTPUT_WINDOW_MS documentation and audit entry 90 to
say the supervised Claude stall window is off by default, but becomes active
when COMMONLY_SUPERVISE_STALL_MS or COMMONLY_SUPERVISE_STALL_MS_CLAUDE is set
above zero; clarify that this supervisor window may cancel a turn before the
first-output window.
Source: Path instructions

Add a supervised stopped-descendant test for tree-wide SIGCONT.

287-295: Trivial · Stability & Availability · Heavy lift

Add a supervised stopped-descendant test for tree-wide SIGCONT.

The real-child test calls claude.spawn directly without the supervisor's process-group option and creates no descendant. The existing supervised process-group test uses a running grandchild and checks group termination, but it does not stop the descendant or verify that its SIGTERM handler runs after SIGCONT.

Add a production-shaped test that runs the watchdog with [OWN_PROCESS_GROUP]: true, stops a descendant in that group, and asserts that the descendant handles SIGTERM before the kill grace expires. The test must fail if the tree-wide SIGCONT is replaced with a root-only signal.

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Review comment at @cli/__tests__/first-output-watchdog.test.mjs around lines 287
- 295:
Add a production-shaped watchdog test around claude.spawn using the
[OWN_PROCESS_GROUP] option and a descendant in the spawned process group; stop
the descendant, then verify its SIGTERM handler runs before the kill grace
period expires. Ensure the test would fail if SIGCONT targets only the root
process.

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cli/__tests__/first-output-watchdog.test.mjs
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cli/src/lib/first-output-watchdog.js
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…IGTERM The freeze test spawned the root only. This one runs the turn in its own group, stops a descendant too, and asserts that descendant ran its SIGTERM handler. With a root-only SIGCONT it fails: the root exits, and the survivor sweep SIGKILLs the descendant before it can clean up. The docs now say the supervised stall window is off for claude by default, and that COMMONLY_SUPERVISE_STALL_MS_CLAUDE or COMMONLY_SUPERVISE_STALL_MS above 0 turns it on. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_015AKgpQ2pr6xRMhN5mcfoHF

lilyshen0722 · 2026-11-01T12:17:02Z

Both points in CodeRabbit's review body at 7224aa5 hold, and both are applied in 5313c86:

Wording. The supervised stall window is off for claude only by default. COMMONLY_SUPERVISE_STALL_MS_CLAUDE or COMMONLY_SUPERVISE_STALL_MS above 0 turns it on, and on a supervised run that window can end a turn first. Both the README row and AX entry 90 now say so.
Test. A new test runs the turn in its own group (ownProcessGroup), stops a descendant along with the root, and asserts the descendant ran its own SIGTERM handler. Reverse check: with the tree SIGCONT swapped for a root-only proc.kill('SIGCONT'), it fails, because the root exits and the survivor sweep SIGKILLs the descendant before it can clean up. Restored, first-output-watchdog.test.mjs passes 37/37.

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Other comments: 1

cli/__tests__/first-output-watchdog.test.mjs: 1
341-343: Minor · Stability & Availability · Quick win

The root exits at once, so the test depends on a timing race.

The root SIGTERM handler calls process.exit(143) immediately. The proc.on('exit', sweepStallSurvivors) hook in claude.js then SIGKILLs the snapshotted descendants.

Both SIGTERM and SIGCONT go to the root and to the stopped descendant at about the same time. The descendant must wake and run writeFileSync before the SIGKILL from the survivor sweep arrives.

On a loaded CI host, the sweep can win. The assertion at line 360 then fails with ENOENT even though the production code is correct.

Make the root keep running until the descendant has written the marker, with a bounded wait. The test stays deterministic with the process-tree SIGCONT.

With root-only SIGCONT, the stopped descendant never writes the marker. The root then exits after the bound, so the reverse check still fails as intended.
Proposed fix
-          const root = "process.on('SIGTERM', () => process.exit(143));"
+          const root = `process.on('SIGTERM', () => { const t0 = Date.now(); const wait = () => (require('fs').existsSync(${JSON.stringify(mark)}) || Date.now() - t0 > 4000 ? process.exit(143) : setTimeout(wait, 20)); wait(); });`
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Review comment at @cli/__tests__/first-output-watchdog.test.mjs around lines 341
- 343:
Update the `root` SIGTERM handler in the watchdog test so it remains alive until
the descendant creates the `mark` file or a bounded wait expires, then exits
with the existing status. Preserve the process-tree SIGCONT behavior and ensure
root-only SIGCONT still fails the marker assertion after the wait.

Additional comments: 1

cli/__tests__/first-output-watchdog.test.mjs-358-360: 1
358-360: Minor · Functional Correctness · Quick win

Unverified finding
Verification ran but could not confirm this finding. It is shown for review, not as a verified issue.

The test does not prove that the descendant exited.

The test records the descendant PID in grandchild. It asserts the marker file, but it never probes whether the PID is gone.

The finally block then SIGKILLs grandchild unconditionally. A surviving descendant would be hidden by that cleanup.

The marker proves that the SIGTERM handler ran. It does not prove that the descendant terminated after the watchdog fired.

Poll process.kill(grandchild, 0) after the spawn_stalled outcome. Assert that it throws ESRCH before cleanup.
Proposed fix
       expect(outcome?.code).toBe('spawn_stalled');
       expect(grandchild).toBeGreaterThan(0);
       expect(fs.readFileSync(mark, 'utf8')).toBe('term');
+      const alive = (pid) => { try { process.kill(pid, 0); return true; } catch { return false; } };
+      const deadline = Date.now() + 2_000;
+      while (alive(grandchild) && Date.now() < deadline) {
+        await new Promise((resolve) => setTimeout(resolve, 20));
+      }
+      expect(alive(grandchild)).toBe(false);
Based on learnings: process-group timeout tests need a recorded descendant PID and a failed kill -0 probe, or an accepted equivalent, to establish descendant termination.

Source: Learnings

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Other comments:
Review comments at @cli/__tests__/first-output-watchdog.test.mjs:
- Around line 341-343: Update the `root` SIGTERM handler in the watchdog test so
it remains alive until the descendant creates the `mark` file or a bounded wait
expires, then exits with the existing status. Preserve the process-tree SIGCONT
behavior and ensure root-only SIGCONT still fails the marker assertion after the
wait.

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The root exited the moment it got SIGTERM, and its exit runs the survivor sweep, which could SIGKILL the descendant before its handler wrote the mark on a loaded runner. The root now waits (bounded) for the mark before it exits, and the test also asserts the descendant is gone before cleanup could hide a survivor. A root-only SIGCONT still fails it: the descendant stays stopped, the bound runs out, and the mark never lands. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_015AKgpQ2pr6xRMhN5mcfoHF

lilyshen0722 · 2026-11-01T12:26:22Z

Both points in CodeRabbit's review body at 5313c86 hold, and df1a30e applies them:

Race. The root now waits, up to a bound, for the descendant's mark before it exits. Without the wait, its exit runs the survivor sweep, which could SIGKILL the descendant before the handler wrote. Reverse check: with a root-only SIGCONT the test still fails (ENOENT on the mark, after the 4 s bound). Restored, it passes.
Termination. After the outcome, the test polls kill(pid, 0) on the descendant and asserts it is gone before the finally cleanup runs.

first-output-watchdog.test.mjs passes 37/37.

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Inline comments:
Review comments at @cli/__tests__/first-output-watchdog.test.mjs:
- Line 344: Update the SIGTERM handler’s `wait` logic so the root waits for the
descendant’s `exit` event before exiting, using the existing timeout as a
fallback; do not treat the marker’s appearance alone as proof that the
descendant has exited.

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The mark lands before the descendant exits. A root that left on the mark could exit in between, leaving a zombie that the kill(pid, 0) probe still sees. The root now waits, bounded, for the descendant's exit and reaps it. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_015AKgpQ2pr6xRMhN5mcfoHF

lilyshen0722 commented Nov 1, 2026

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Comment thread cli/__tests__/first-output-watchdog.test.mjs Resolved

lilyshen0722 added this pull request to the merge queue Nov 1, 2026

Merged via the queue into main with commit 8a9006d Nov 1, 2026
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fix(cli): a frozen claude turn is cancelled at its window, and the seat names that window - #3226

fix(cli): a frozen claude turn is cancelled at its window, and the seat names that window#3226
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