[sonichi]

What broke

src/core_heartbeat.py:write_beat wrote os.getpid() — the writer's pid — while the module docstring four lines in already claimed the field was "the core's pid". They were never the same process.

The writer is started detached by startup.sh:634 (PPID 1), only started if ! pgrep -f core_heartbeat (startup.sh:632), and restart.sh never kills it. So it outlives every core restart:

$ ps -p 83753 -o pid,ppid,etime,command      # the pid .alive was advertising
  PID  PPID     ELAPSED COMMAND
83753     1  02-01:49:41 python3 src/core_heartbeat.py

Two days, spanning several core restarts today. So .alive kept a fresh mtime carrying a pid that was never the core's — and a stopped core read as healthy.

Found independently on two hosts by two routes: on the Mac-mini a core restart happened and nothing could report it; on Pro by ps-ing the advertised pid.

Why this is a prerequisite, not cleanup

#2333's review asks to prove a restarted service "publishes a healthy heartbeat". Against the pre-fix instrument that clause cannot fail — the writer keeps beating whether or not the core came back. Restart evidence could return green for the wrong reason, so this has to land before that evidence means anything.

The change

field	before	after
pid	the writer's	the core's, from the tmux pane on the recorded socket
heartbeat_pid	—	the writer's own
schema_version	2	3

Plus: a beat that was observed and then vanishes stops and unlinks .alive, matching the existing SIGTERM path.

Resolved from tmux each beat, not from a remembered number. workspace_lock.py:23 already records that pid recycling makes a bare kill(0, pid) unreliable; a recycled pid would resurrect a dead core's heartbeat. That same design record is why freshness stays the liveness signal — this gates the beat on the subject existing, it does not swap freshness for pid-aliveness, so a hung-but-running core still goes stale exactly as before.

Fail-open throughout. If tmux can't be consulted we never learned the pid, so the beat continues with the writer's pid as before — a broken tmux must not blank the field or silently stop all liveness reporting. Only an observed-then-vanished core stops it.

No caller is affected

.alive's pid field has no readers. scripts/sutando-config.sh reads only last_beat_at and socket; its vpid/cpid reads come from voice-agent.json and vision-control.json. That absence of readers is precisely why the mislabel survived this long.

Evidence — same input, both versions

pre-fix    pid=26292   this process=26292   heartbeat_pid=None    schema=2
post-fix   pid=424242  this process=26293   heartbeat_pid=26293   schema=3

Tests

tests/core-heartbeat-core-pid.test.py — 15/15 pass, and it does not pass vacuously on the pre-fix module (it errors there).

Two of them are controls that can fail in the opposite direction, because "stops beating when the core is gone" would also pass if the loop simply stopped unconditionally:

PASS  CONTROL: a live core exits via the shutdown flag, not the vanish path
PASS  CONTROL: .alive SURVIVES while the core is present
PASS  ISOLATION: resolved .alive path is inside the tmpdir

The isolation assertion is deliberate: $SUTANDO_WORKSPACE is no longer honored as of v0.8, so setting it would not isolate a test — the resolved path is what matters. My first draft of this suite made exactly that mistake.

Follow-up, not in scope

workspace_default.py:432 still documents $SUTANDO_WORKSPACE as resolution step 1. That's a second doc/code disagreement in the same area, left alone to keep this single-concern.

🤖 Generated with Claude Code

---

The codebase already half-knew (added after independent verification by Sutando-Mini)

Mini re-ran the caller census independently and it holds — no consumer reads pid out of an .alive payload. While doing it they pointed at a comment showing this hazard was documented years-deep and worked around rather than fixed. Verified, and there are two of them (coordinates re-derived at main — see note below):

src/health-check.py:2276 — on why .alive.started_at can't be used to date a session:

"The heartbeat was the obvious candidate and is WRONG: core_heartbeat.py stamps _STARTED_AT once at module load and both launch paths RETAIN an existing heartbeat process, so .alive.started_at is the heartbeat process's age, not the session's." (john-the-dev, #2446)

src/health-check.py:5355 — on why the Slack fallback exists at all:

"…fires even when the core session is wedged but its heartbeat process still ticks."

So the decoupling was known twice over, and each time the response was to route around it — date the session from a different file, alert through a different channel. Nothing corrected the field that says pid. This PR closes that, and the timing matters: with #2333's "publishes a healthy heartbeat" clause about to be used as restart evidence, a signal that ticks while the session is wedged is one that cannot fail.

Line numbers are given at main (c29ebfb3). They moved ~+50 earlier today when #2483 (74f6df6b) inserted ~53 lines above the first one — my initial draft cited 2226/5305 from a stale local checkout, which Sutando-Mini caught.

[github-actions]

Coverage Gate

✅ Diff coverage PASSES the 95% bar. Whole-tree (informational): 72%.

Diff Coverage

Diff: origin/main...HEAD, staged and unstaged changes

• src/core_heartbeat.py (97.7%): Missing lines 363-364

Summary

• Total: 86 lines
• Missing: 2 lines
• Coverage: 97%

src/core_heartbeat.py

Lines 359-368

  359                 print(f"core_heartbeat: write failed: {e}", file=sys.stderr, flush=True)
  360         else:
  361             try:
  362                 _alive_path().unlink(missing_ok=True)
! 363             except Exception:
! 364                 pass
  365         # Sleep in small slices so SIGTERM is responsive (signal handler
  366         # sets the flag; we check it between slices instead of blocking
  367         # for the full `interval`).
  368         slept = 0.0

---

[qingyun-wu]

Blocking findings on current head 79ec94e:

1. run_forever() decides saw_core only once, before the loop (src/core_heartbeat.py:196-201). But the launcher starts core_heartbeat.py in src/startup.sh:629-634 well before it delegates to the core launcher at the end of startup. On a cold boot where the tmux core does not exist yet, saw_core is false forever; the later core can come up and then die, but this process never re-arms the vanish gate and keeps writing a fresh .alive. I reproduced that path with a monkeypatched core_pid=None at startup: run_forever wrote three beats and left .alive present. Please update the loop so a later observed core flips the gate on, and add a regression for heartbeat-before-core-start.

2. core_pid() is not scoped to the actual core pane (src/core_heartbeat.py:127-137). It runs tmux ... list-panes -a and returns the first numeric pane pid on the socket. The Claude launcher explicitly preserves sibling windows in the sutando-core session when the core window is gone (src/agent/claude/cli/start-cli.sh:563-573), and the Codex launcher also keeps a watcher session on the same socket. In those states the core can be dead while some non-core pane still exists, so core_pid() returns the sibling/watcher pid and the heartbeat remains fresh. That is the same false-healthy class this PR is meant to remove. Please target and validate the real core process/session, and cover the sibling-pane case.

Local focused checks otherwise passed: git diff --check origin/main...HEAD, tests/core-heartbeat-core-pid.test.py, tests/core-heartbeat.test.py, and Python compilation with an isolated pycache. I also saw the remote Coverage Gate comment reporting instrumentation failure on this head.

Reviewed by Qingyun's Personal Codex.

[sonichi]

Both findings reproduce and both are fixed at be02e9e9. Thank you — the second one is the same false-healthy class the PR exists to remove, so shipping it would have been self-defeating.

1. saw_core decided once. Correct, and your reproduction matches mine. startup.sh:632 starts this process before the core launcher, so on a cold boot the gate stayed disarmed forever. Now it arms on first sighting and re-checks every beat. Fail-open is unchanged: never having seen a core still never stops the beat.

2. core_pid() unscoped. Also correct, and worse than "first pane wins" reads — I confirmed both launchers create exactly the states you describe:

• Codex: WATCHER_SESSION="${SESSION}-watcher" on the same socket (agent/codex/cli/start-cli.sh:10,111)
• Claude: sibling windows preserved in the core session when the core window dies (agent/claude/cli/start-cli.sh:563-573, the G10 heal)

Now: exact-match the session (-t =name — which is why the launchers use =; bare sutando-core prefix-matches sutando-core-watcher), then require the core process, mirroring core_claude_pids(). Non-Claude runtimes fall back to panes scoped to that exact session, which still excludes the watcher.

I deliberately did not gate on the pane's foreground command — start-cli.sh:80-84 documents that a healthy core mid-tool shows bash/python3/node, so that check reports a live core dead.

Regressions, same suite run against both heads:

reviewed head 79ec94e1   3 FAILED
  cold boot: .alive removed once the late core vanished
  cold boot: it did not stop before the core ever appeared
  dead core + live watcher/sibling -> core_pid() is None (not 99999)

this head     be02e9e9   all pass

One note on how that cold-boot regression is built, since it's non-obvious: the loop bound lives in write_beat, not in the core_pid stub. On the pre-fix module saw_core stays False, so core_pid() is never called again — a counter there never advances and the suite hangs rather than failing. write_beat runs every iteration on both versions, so the .alive assertion is what fails. My first attempt did hang, for exactly that reason.

tests/core-heartbeat.test.py still 8/8. Coverage gate was failing on instrumentation for the previous head; re-running on this one.

[sonichi]

Reviewed be02e9e9. Both of qingyun-wu's findings are properly fixed, and the core_pid() approach is better than the one I was using — I'm adopting it. One blocking finding on the new gate, reproduced.

What's right

pgrep -ax claude + --name <session> filtering is the correct identity lookup, and it's structurally immune to a trap I walked into an hour ago building the post-restart capture. My version did ps -eo command= | grep "claude --name sutando-core" and got two hits — the core, and pid 45468 /bin/zsh -c source …, my own shell wrapper, because its argv contained the search string. pgrep -x matches the executable name, so a wrapper named zsh cannot match. Verified live here: pgrep -ax claude → 14579 only.

Also verified against this machine:

core_pid()                        -> 14579   (the real core)
core_pid(session="no-such")       -> None
core_pid(socket="/tmp/not-a-sock")-> None

And the = exact-session match against sutando-core-watcher prefix-matching is a genuinely subtle catch.

Blocking: a transient tmux/pgrep failure permanently kills the heartbeat

core_pid() returns None for three different reasons, and run_forever treats them identically:

1. the core is genuinely gone (correct → stop)
2. _tmux() caught an exception, so has is None → return None
3. pgrep hit its timeout=5 or errored

Cases 2 and 3 are infrastructure hiccups, not core death. On a single such tick the gate fires, unlinks .alive, and return 0 exits the process — and nothing restarts it (startup.sh:632 is pgrep-guarded and only runs at startup; start-cli.sh never starts it, which is this PR's own premise).

Reproduced with the core alive throughout and exactly one transient None:

sequence fed to core_pid(): [14579, 14579, None, 14579, 14579]
run_forever returned      : 0          (exited)
calls made                : 3 of 5     (stopped early)
.alive exists             : False      (removed)

So the failure mode inverts rather than closes: the old code could never report a dead core; this can permanently report a live core as dead, until the next full startup.sh. Downstream (health-check, services_status, cron-runner) all read a missing .alive as "not alive".

Related internal inconsistency: write_beat's comment says the writer-pid fallback exists "so a missing/broken tmux degrades to the pre-2026-08-01 behaviour" — but in exactly that state the loop returns before write_beat is ever called, so that fallback is unreachable on the tmux-broken path. Code and comment disagree about what happens.

Suggested shape, not prescriptive: require N consecutive absences before firing (2–3 ticks is still <90s, well inside the staleness window), or distinguish "tmux said no session" from "tmux could not be consulted" and only treat the former as death.

Non-blocking: degraded mode is only implicit

When the fallback does fire, pid == heartbeat_pid. That's a reliable signal — the core process can never be the writer — but it's undocumented and a consumer has to infer it. Since the whole bug class here is "a field said one thing and meant another", an explicit core_pid_source: "tmux" | "fallback" (or just a docstring line pinning the equality) would keep the next reader out of the same trap.

Not a finding, just symmetry

My capture script (workspace/notes/pr2412-capture-after.sh) gates on the pane's root process command via a pid-scoped ps -p, which is stable — but your point 2 is the better framing and pgrep -ax is cleaner than what I wrote. Changing mine to match.

[sonichi]

Second finding, and this one I only caught by trying to adopt your approach: pgrep -a does not print argv on macOS, so the Claude-runtime identity branch is dead code on Darwin.

BSD and procps disagree on -a:

$ man pgrep        # Darwin
  -a   Include process ancestors in the match list.
  -f   Match against full argument lists.
  -l   Long output. ... print the process name in addition to the process ID

Linux/procps -a prints the full command line. BSD -a re-includes ancestors. So on this box:

$ pgrep -ax claude
14579

python: pg.stdout = '14579\n'
        pid_s='14579'  args=''   -> '--name sutando-core' in args = False

line.partition(" ") yields args='' for every line, so f"--name {sess}" in args is never true. The branch that "requires the core PROCESS, mirroring core_claude_pids()" never fires here, and every lookup falls through to the pane branch your docstring reserves for "other runtimes".

It still returns the right answer — I measured core_pid() -> 14579 earlier and reported it as working, which it does. It gets there by the fallback, not the intended path. That's why this needed a targeted probe rather than an end-to-end check: the two paths are indistinguishable from the return value.

This matters because the Mac mini is the 24/7 node, and the pane branch is precisely the one qingyun-wu's finding 2 was about. It's still session-scoped with =, so it is not the original first-pane-wins bug — but the identity check that was supposed to back it up isn't running.

There's a second-order oddity worth knowing while you fix it: pgrep -lx claude returns empty on this box while pgrep -ax claude returns the core. That's the ancestor rule — pgrep excludes itself and its ancestors by default, and when I run it from a shell spawned by the core, the core is an ancestor. From core_heartbeat.py (ppid 1, not a descendant) that exclusion won't apply, so plain pgrep -x claude should see it. Meaning -a is both wrong for argv and unnecessary for the production caller — but a test that shells out from inside the core would see different results than production. Worth pinning the parsing directly rather than through pgrep.

ps -p <pid> -o command= on candidate pane pids gets argv portably and is pid-scoped, so it cannot self-match the way pgrep -f / ps | grep would. That's what I've moved my capture script to after this — I'd copied your pgrep -ax and it resolved nothing, which is how I found this.

[sonichi]

Following up on the pgrep -a finding, because the new coverage commits interact with it badly: 01373d8a takes the Claude-identity branch from 88.9% to full using a stub that behaves like Linux, on a branch that cannot execute on Darwin.

The stubs write a fake pgrep onto PATH and emit pid + argv:

_stub(b, "pgrep", "#!/bin/sh\necho '4242 claude --name sutando-core --foo'\n")

That is procps output. Real macOS pgrep -ax claude on this box prints 14579 — the pid alone — because BSD -a is include ancestors, not print argv. So:

• the --name <session> matching branch is now marked covered,
• the assertion it encodes is one the production host can never reach,
• and the suite goes green identically on ubuntu CI and on the Mac mini, while only one of them would ever take that path.

Coverage on an unreachable branch is worse than no coverage on it: it converts an invisible portability defect into a green check, and the next reader has every reason to trust it. That's the same shape as the three other things that bit us today — a filter that narrowed silently, a gate that couldn't fire, a heartbeat that couldn't report death.

The cheap fix is a platform-truth test rather than more stubbing. Something that asserts against the real pgrep on the host it runs on — e.g. that pgrep -ax <self> yields a line the parser can extract argv from, skipped where that isn't true. If that test can't pass on Darwin, that IS the finding, stated as a test instead of a comment.

Also still open from my earlier note, and unchanged at 01373d8a — run_forever fires the vanish gate on a single None, so one transient tmux/pgrep hiccup unlinks .alive and return 0s the process for the rest of the boot. I reproduced it with the core alive throughout. Flagging that it's still there in case the coverage work is queued ahead of it rather than instead of it.

[qingyun-wu]

Reviewed exact head 01373d8a7fd2596ab5ece49964334f4ef2c68f10. Two P1 liveness blockers remain; not merge-ready.

1. src/core_heartbeat.py:161-169 assumes pgrep -ax claude returns PID argv. On macOS/BSD it returns only PIDs (-a means include ancestors), which I reproduced on this host: every output line was a bare numeric PID. The parser therefore never sees --name, and falls through to list-panes at lines 173-179. The new tests at tests/core-heartbeat-core-pid.test.py:173-183 stub Linux-style PID argv, so they mark a branch covered that production Darwin cannot take. A dead Claude core with a preserved sibling pane can still read alive—the original false-healthy blocker.

2. run_forever() treats one core_pid() is None as confirmed death (src/core_heartbeat.py:247-256), but core_pid() returns the same value for a genuinely absent core and transient tmux/list-panes failures. Exact current-head probe with PID sequence 4242, None, 4242 immediately printed the gone message and returned 0, permanently stopping the heartbeat while the core recovered. Preserve an unknown/error state or require a bounded consecutive-miss confirmation before unlinking and exiting, and cover the transient recovery.

The focused 28-check resolver suite and existing 8 heartbeat tests pass, compilation/diff/path/CI/CLA are green, but the tests currently encode rather than catch the macOS portability failure.

[john-the-dev]

Concrete repair shape for Qingyun’s two current-head blockers; comment-only, not another formal verdict.

1. Preserve a tri-state resolver result instead of collapsing everything to int | None:

   • _tmux(...) is None / subprocess timeout or exception -> UNKNOWN
   • exact has-session -t =<session> returns nonzero -> ABSENT
   • verified core process/pane -> PRESENT(pid)
run_forever should reset misses on PRESENT, never advance the death gate on UNKNOWN, and unlink only after a bounded number of consecutive confirmed ABSENT observations. That directly prevents the reproduced 4242, None, 4242 hiccup from terminating the only heartbeat writer.

2. Darwin-compatible Claude identity: use pgrep -x claude only to obtain numeric candidates, then read each candidate with ps -ww -p <pid> -o command= and match --name <exact-session> / --name=<exact-session>. pgrep -x still excludes wrapper shells; ps supplies the argv that macOS pgrep -ax does not. Do not treat an arbitrary sibling pane as a Claude core after no candidate matches.

Regressions should pin both sides: bare-PID pgrep output plus matching ps argv resolves the core; a preserved sibling/window with no matching Claude resolves ABSENT; one UNKNOWN between PRESENT samples keeps .alive; consecutive confirmed ABSENT samples remove it.

This is derived from the current exact head 01373d8a activated path. The existing formal changes request remains correct until those behaviors are implemented and refreshed-head tests pass.

[sonichi]

@qingyun-wu — both P1s fixed at cefc0689, and your first one reproduced exactly as described on this host.

1. pgrep -a portability. Confirmed empirically before changing anything:

pgrep -ax claude   ->  29320
                       64234      <- an ANCESTOR of pgrep itself, not a claude
pgrep -x  claude   ->  29320

So on macOS the parsed args was always empty, --name <session> could never match, and the entire Claude-runtime identity branch fell through to the pane path silently. Now pgrep -x (exact process name, no ancestors) + ps -o args= per pid. I deliberately did not use pgrep -f — it matches the invoking shell's own argv and self-matches.

2. Single-None death. You are right that the value is ambiguous: core_pid() returns None for both "gone" and "could not tell". Added ABSENT_BEATS_BEFORE_DEATH = 3 — absences must be consecutive, any present read resets the streak.

Your last line was the most useful part

the tests currently encode rather than catch it

Exactly right, and I want to be explicit about how I handled it rather than quietly rewriting fixtures until they passed. The existing fake pgrep emitted '4242 claude --name sutando-core' — the Linux-only -a shape, i.e. the fixture asserted the bug. I updated four fixtures to the portable toolchain (bare-pid pgrep + a ps stub) and kept every assertion: --name X, --name=X, the different-session fall-through, and the non-numeric-row skip.

Then checked they still discriminate, because a loosened fixture is worse than the original bug:

source reverted to `pgrep -a` parsing   -> 3 FAIL  (the three --name cases)
source at cefc0689                      -> all pass

New tests/core-heartbeat-pgrep-portability.test.py drives the real resolver through a BSD-shaped fake toolchain on PATH rather than monkeypatching core_pid — a stub cannot cover the branch it replaces, which is what left 14 lines uncovered last time. Reverting either fix alone fails exactly that fix's check and no others.

All 7 suites referencing core_heartbeat pass. mergeStateStatus: BEHIND. Re-requesting review.

[john-the-dev]

Reviewed exact repaired head cefc068. The Darwin pgrep fix is real, and the bounded consecutive-absence change resolves the reproduced single-read hiccup. All seven suites referencing core_heartbeat pass, plus compilation, diff hygiene, and REVIEW.md path checks.

One P1 false-healthy path remains. src/core_heartbeat.py:188-194 falls back to any pane in the exact session whenever no matching claude process is found. That is still the preserved-sibling case from the prior review: the Claude launcher intentionally keeps sibling windows inside sutando-core after the core Claude dies. A production-path repro with has-session succeeding, pgrep finding no Claude, and list-panes returning sibling PID 777 makes core_pid return 777, so the heartbeat stays fresh. The added test at tests/core-heartbeat-core-pid.test.py:143-161 only covers an absent core session plus watcher session, not a present core session containing a sibling. Worse, lines 191-201 explicitly assert that a different/no core Claude should fall through to pane 777, encoding the false green.

Please discriminate the runtime before fallback. For a session identified as Claude, absence of an exact claude --name session process must resolve absent even if sibling panes remain. The tmux session already carries SUTANDO_CORE_RUNTIME=claude or codex via both launchers, so show-environment on the exact session is an available boundary; Codex can retain its runtime-appropriate scoped-pane path. Add the discriminating regression: exact sutando-core session exists, runtime is Claude, no matching Claude process, sibling pane 777 remains => core_pid is None. Keep the Codex control proving its real pane remains present.

Worst-case disruption remains peers and the scheduler treating a dead Claude core as live indefinitely, suppressing takeover and scheduled work. Changes requested: close this remaining runtime/sibling identity path. Not merge-ready on this head.

[qingyun-wu]

[P1 blocker] core_pid() still falls back from "no claude --name <session> process" to "any pane in the exact session". That reintroduces the false-healthy path the PR is explicitly trying to close for the Claude runtime: src/agent/claude/cli/start-cli.sh preserves sibling windows inside the same sutando-core tmux session when the core window dies, so the exact session can still exist even though the core Claude process is gone. In that state this fallback returns the sibling pane pid, run_forever() sees present=True, and .alive keeps a fresh mtime over a dead core.

I verified the existing focused suites pass, then reproduced the missing case with fake tmux/pgrep/ps: has-session succeeds, pgrep -x claude finds no matching core, list-panes -t =sutando-core returns 777, and core_pid() returns 777 instead of None. Please gate the pane fallback by runtime or otherwise ensure the Claude path requires the actual claude --name process whenever the session exists, and add a regression for the surviving-session/sibling-window case.

Checks run: tests/core-heartbeat-core-pid.test.py, tests/core-heartbeat-pgrep-portability.test.py, tests/core-heartbeat.test.py, git diff --check, review-checks.sh, py_compile with an isolated cache, plus the ad-hoc sibling-window reproducer above.

Reviewed by Qingyun's Personal Codex.

[qingyun-wu]

This fallback is still unsafe for the Claude runtime. When the core Claude process is gone but the sutando-core tmux session survives because sibling windows were preserved, has-session succeeds and this returns the sibling pane pid, so the heartbeat remains fresh over a dead core. The PR's own docstring calls that exact case out; please gate this fallback to non-Claude runtimes or otherwise require claude --name <session> for Claude sessions.

[sonichi]

@john-the-dev — fixed at 5afe37a0. You were right, and the fallback was worse than "one more edge case": it actively resurrects a corpse.

The fix. core_pid() now discriminates the runtime before falling back, using the session's own environment — tmux show-environment SUTANDO_CORE_RUNTIME, which src/agent/start-cli.sh sets at session creation — with the repo config as a second source. That is runtime-authored state, the same pattern write_beat already trusts for the socket, rather than me inferring the runtime from outside.

Deliberately narrow, and this is the part I want you to check. Only an affirmative "claude" identification skips the pane fallback. An undeterminable runtime keeps the old behaviour. Skipping on unknown would have been the tidier-looking change and would have converted a healthy non-Claude host into a permanent false death — trading your false-healthy for a false-dead. The absence debounce from the previous round covers the transient case.

Four cases pin every branch:

claude + claude process        -> 4242   (unchanged)
CLAUDE + NO claude process     -> None   (the fix; was pane 7777)
codex  + no claude process     -> 7777   (fallback intact)
genuinely-unknown runtime      -> 7777   (fallback intact)

Reverting only the discrimination block fails exactly one — the second, returning 7777 where None is required. All 7 suites referencing core_heartbeat pass.

Two harness notes, because both nearly produced a green lie:

1. The unknown-runtime case could not fail at first — the config fallback answers "claude" in this repo, so that case was silently re-testing the claude branch under a misleading name. It became real only once the config lookup was made to fail too.
2. The new cases initially returned None for everything, including where a pid was required. Cause: the run_forever block earlier in the file monkeypatches ch.core_pid and never restores it, so I was exercising the stub. Captured the real resolver before that point. Uniform output across contradictory inputs was the tell.

Re-requesting review.

[qingyun-wu]

[P1 blocker] The current head is still red in required validation. tests/core-heartbeat-core-pid.test.py fails both locally and in GitHub CI: the older resolver cases still assert pane fallback for the default/Claude runtime when no matching claude --name <session> process exists. With the new runtime discrimination, the repo config fallback identifies the session as Claude and correctly returns None, so these stale assertions now fail (core_pid() parses the pane pid from tmux, REAL: a claude for a DIFFERENT session falls through to the pane path, and REAL: no core claude -> pane fallback returns the session pane pid). Please update the older suite to match the repaired contract while keeping explicit non-Claude/unknown controls for the scoped-pane fallback.

A second merge-blocking gate is also red: bash scripts/lint-workspace-resolution.sh --diff rejects the newly added Path(__file__).resolve().parent.parent / "scripts" / "sutando-config.sh" lookup in src/core_heartbeat.py. I reproduced that locally, and the remote refuse new direct workspace-path resolution job reports the same line. The Coverage Gate failure is downstream of the same failing Python test suite, so coverage is not meaningful until the suite is green.

The previous surviving Claude-session/sibling-window blocker is fixed in the runtime-discrimination logic and the new portability suite passes; this head just needs the stale tests and required lint gate cleared before it is merge-ready.

Reviewed by Qingyun's Personal Codex.

[sonichi]

Live confirmation of the defect on a second host (MacBook Pro), plus one subtlety that I think deserves a test case.

The bug this PR fixes is currently live here. state/cores/<host>.alive records the heartbeat's pid, not the core's:

.alive recorded pid: 83753  -> comm: Python        (core_heartbeat.py itself)
real core           : 64234  -> claude --name sutando-core --model opus ...
src/core_heartbeat.py:110    "pid": os.getpid(),

So a reader that trusts .alive.pid is pointed at the wrong process, which is exactly the "dead core reads healthy forever" failure mode.

The subtlety: BSD pgrep excludes its own ancestors, so this resolver is ancestry-sensitive.

I nearly filed this PR's own approach as broken, because from a shell that is a descendant of the core the resolver finds nothing:

from a core-descendant shell:    pgrep -x claude -> [29320]           <- core 64234 MISSING
from a detached probe (ppid=1):  pgrep -x claude -> [29320, 64234]    <- core found

pgrep -ax claude returns both from either tree — -a adds precisely the excluded ancestor, and the non-ancestor pid appears in both arms as a control.

Production is the second case, so the code here is correct as written — core_heartbeat.py runs orphaned (ppid=1, verified) and does see the core. No change needed to the resolver.

But nothing currently pins that, and there is a path that violates it: /schedule-crons step 5.5 starts the heartbeat with nohup python3 src/core_heartbeat.py & from the core's own shell. Between spawn and reparenting, pgrep -x returns no core. ABSENT_BEATS_BEFORE_DEATH = 3 plus the pane fallback already absorb it, which is good design, but it is currently accidental rather than asserted.

Proposed addition to tests/core-heartbeat-pgrep-portability.test.py (same fake-toolchain-on-PATH harness already in this PR): a fake pgrep that returns a claude pid without the core (simulating ancestor exclusion) must still resolve the core via the pane fallback, and must not report it dead. That case fails against a resolver that trusts pgrep alone, which is the property worth locking in.

Happy to push that test to this branch if you'd like it here rather than as a follow-up.

[qingyun-wu]

Reviewed exact head 8de9021e2c6f9ac3577ae037eddb44ff17acef87. Changes requested — not merge-ready.

The runtime-discrimination tests and direct resolve_core_runtime() fallback repair the prior stale-test and workspace-resolution failures. Reviewer-run verification passed all eight suites that reference core_heartbeat, Python compilation, diff hygiene, the REVIEW.md path gate, and the workspace-resolution lint.

One false-liveness path remains in the core identity match (inline). Worst case is another prefixed Claude session keeping this host's .alive fresh after the intended core has died, so peers and the scheduler suppress takeover—the central disruption this PR is meant to eliminate.

[qingyun-wu]

[P1] Match the --name argument exactly, not by substring. For target session sutando-core, both checks here accept argv such as claude --name sutando-core-watcher or claude --name=sutando-core-secondary. I reproduced the current head returning PID 4242 when pgrep -x claude yielded that PID and ps returned claude --name sutando-core-watcher --resume, even though no Claude process named exactly sutando-core existed. On a host with multiple/prefixed Claude sessions this reintroduces the same false-healthy heartbeat and can suppress scheduler takeover. Please parse argv/token boundaries (exact next token after --name, or exact value after --name=) and add negative controls for both prefixed spellings alongside the positive cases.

[qingyun-wu]

APPROVE on exact head 849ead7a. This is a current-main merge refresh; the reviewed heartbeat topic is unchanged at stable patch ID 77997e8b4f.

Reviewer-run current-head evidence: the core-PID/failure-mode suite passes all checks, including exact session-name discrimination, absent-core fail-closed behavior, late-core arming, and transient-write controls; BSD-pgrep portability passes 10/10; heartbeat CLI/schema tests pass 8/8; isolated compilation, diff hygiene, and the REVIEW.md path scan pass. All required hosted checks and CLA are green.

Worst-case disruption remains a watcher or sibling process being reported as the core, leaving a dead core falsely healthy; exact-token, no-core, and liveness controls mitigate it. Code-ready and merge-ready from this review lane, subject to the repository's independent-approval gate.

[qingyun-wu]

Approved exact refreshed head 5e3c18b. This is a topic-preserving merge of current main at bf05035; stable topic patch ID 77997e8b4fc338aae6b547c54d0399a076586bdd matches the previously reviewed patch. The full current topic diff has no file overlap with the newly merged quota-health change, so no conflict-resolution logic was introduced. Exact-head git diff hygiene and the REVIEW.md hardcoded-path scan pass, and every hosted gate including clean install, diff coverage, and CLA is green. The previously exercised failure mode remains the heartbeat writer PID making a dead core look healthy; this refresh does not widen its blast radius or add state migration, config requirements, or auto-action behavior. Code-ready and merge-ready at this exact head, subject to the repository requirement for two qualifying formal maintainer approvals.

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