/collab-monitor

Use the packaged monitor whenever a collab lane needs forward-only delivery to a declared listen name. Do not hand-roll a grep/tail loop: the recorded fleet failures are pinned in this skill's evals.

Start and Stop

COLLAB_MONITOR=$HOME/.golems/skills/golem-powers/collab-monitor/scripts/collab-monitor.sh
: "${ORCHESTRATOR_REPO:?ORCHESTRATOR_REPO must be set}"
 
# Durable background monitor over N explicit files
bash "$COLLAB_MONITOR" start @your-listen-name \
  "$ORCHESTRATOR_REPO/collab/FLEET-STANDING.md" \
  "$ORCHESTRATOR_REPO/collab/ARM-MONITORS.md"
 
# Keep this foreground stream attached to the orchestrator's monitored command session
bash "$COLLAB_MONITOR" follow @your-listen-name
 
# Verify or stop it without remembering a PID
bash "$COLLAB_MONITOR" status @your-listen-name
bash "$COLLAB_MONITOR" stop @your-listen-name

Use foreground mode when a parent monitor/supervisor owns the process:

bash "$COLLAB_MONITOR" run @your-listen-name collab.md another-collab.md

start is the durable producer; it does not wake an orchestrator by itself. Attach follow in a monitored long-running command session before relying on alerts. Each successful start begins a fresh session log, and follow replays that session from its start before streaming new records until stop ends the monitor.

run --once performs one deterministic seed/poll and exits. It is appropriate for evals or an external scheduler; repeated calls use the same durable state. It exits non-zero when initial input, lock/state access, or event extraction fails, so a scheduler must treat non-zero as an incomplete poll.

Participation Law — a collab is a mailbox with no doorbell

Ratified by Etan 2026-08-14 after two leads and a worker each missed messages addressed to them in a shared collab. Writing to a collab makes a message durable, not delivered. Nobody is notified. A participant without a watcher on that file will not see it, no matter how urgent.

These rules bind every participant for the life of the collab.

1. Arm before you work. The moment you post to a collab, are addressed in one, or are named a participant — arm a watcher on that file BEFORE doing anything else. Not after your task, not when convenient. An unwatched collab you are named in is an unread inbox.
2. Waiting means detached, not looping. When you finish a unit and are waiting to be re-requested: detach a watcher and RETURN. Never hold a foreground turn open to poll, and never inspect another agent's pane to infer state — that is monitoring you were not asked to do, and it burns a turn that should have ended.
3. Codex agents have no Monitor tool — use a background bash tail. This is not optional and not a lesser substitute:

   tail -n0 -F <collab-path> &     # detached, then RETURN
   

   Read what it captured when you are re-invoked. A Codex that keeps working, or keeps polling in the foreground, because "it has no monitor" is choosing the wrong half of the contract.
4. Dedup by line hash. A collab that gets rewritten (formatting, section moves) must not re-emit its whole history as new events. Hash lines; emit only unseen ones.
5. Stop when you post your DONE — not before, not after. The watcher's life is exactly the lane's life. A watcher outliving its lane is noise; a lane outliving its watcher is a silent handoff.
6. Pings are pointers, never restatements. In-pane: one line saying WHERE to look and the one fact that makes it urgent — Read <file> §<section> — your worker is blocked. The collab holds the detail because the collab survives restarts and the pane does not. A long message duplicating a collab post is backwards, and long payloads break the receiving pane.
7. Leads own reviewer monitoring; workers push, notify, stop. A worker that keeps watching its own reviewer has taken the lead's job and stayed alive to do it.

Failure mode to recognize: if a handoff "went unanswered", check whether the recipient had a watcher on that file before concluding anything about the recipient. Silence from an unwatched collab is not refusal, disagreement, or absence — it is a message that was never delivered.

Arming Is Step 0 — at boot, and again after every compaction

Ratified into doctrine 2026-08-19 from the 2026-08-17 fleet-degradation retro. The doctrine above was not unreliable — it was never armed. A lead only runs when it is spoken to, so a lead that has not armed a watcher is idle by construction. Etan, on the week that produced this section: "you and cmuxlayer Claude lead are both just not really moving things along until I ping you."

Arm before you dispatch. Arming is step 0 of every lead boot, and step 0 again after every compaction — a monitor dies with its session and nothing re-arms it. A compacted lead with workers in flight and no watcher is the exact failure this section exists to stop. Verify with bash "$CM" status @<listen-name> before you send the first worker prompt; if it is not armed, you are not a lead yet.

Command 1 — the collab watch (arm, then attach)

CM=$HOME/.golems/skills/golem-powers/collab-monitor/scripts/collab-monitor.sh
: "${ORCHESTRATOR_REPO:?ORCHESTRATOR_REPO must be set}"
 
bash "$CM" start  @<listen-name> "$ORCHESTRATOR_REPO/collab/<your-collab>.md"
bash "$CM" status @<listen-name>   # prove it armed BEFORE you dispatch

start is the durable producer and does not wake you by itself. Attach the stream in the same turn, with the harness Monitor tool (Claude seats) — follow replays the session then streams:

Monitor({
  command: 'bash $HOME/.golems/skills/golem-powers/collab-monitor/scripts/collab-monitor.sh follow @<listen-name>',
  description: '@<listen-name> collab mail',
  persistent: true,
})

Codex seats have no Monitor tool: use the background tail in Participation Law rule 3 instead.

Command 2 — the PR-state watch

One notification per state change, and it exits by itself when the PR reaches a terminal state, so it cannot outlive its lane. This is the shell to run — pass it verbatim:

PR=<number>; prev=""
while true; do
  cur=$(gh pr view "$PR" --json state,reviewDecision \
        --jq '"\(.state) review=\(if (.reviewDecision//"")=="" then "NONE" else .reviewDecision end)"' 2>/dev/null || true)
  [ -n "$cur" ] && [ "$cur" != "$prev" ] && echo "PR#$PR $cur"
  prev="$cur"
  case "$cur" in MERGED*|CLOSED*) exit 0;; esac
  sleep 60
done

Claude seats hand that block to the harness as Monitor({ command: <the block>, description: 'PR #<number> state + review decision', persistent: true }). Codex seats run it detached per Participation Law rule 3.

The jq filter is single-quoted, and that is load-bearing. jq's \(…) interpolation is legal only inside a "…" string literal. Spell the filter with double quotes and the shell eats them, jq receives a bare \(...) and dies with failed to parse jq expression … unexpected token "\\" on every tick — a watcher that emits nothing, never exits, and looks armed. Verified 2026-08-19: the double-quoted spelling exits 1 with that parse error; the single-quoted one prints OPEN review=NONE for #729 and MERGED review=NONE for #728, and the MERGED*|CLOSED* case then exits 0.

reviewDecision comes back as an empty string, not null, on a PR with no review — which is why the if … == "" branch is there and why a bare // "none" fallback silently prints nothing.

Filter discipline — a crisis filter keeps firing after the crisis

A watch written while something is burning is scoped to the fire, and then outlives it. Two live specimens from this fleet:

• a PR-state watch left broad enough to narrate every unrelated lane's PR back to the user;
• a collab watch matching @skillcreator that woke the lead on the lead's own posts.

The rule, in three parts:

1. Match what is addressed TO you — the anchored routing grammar below, not a bare tag scan.
2. Exclude your own byline — this monitor classifies self-authored blocks as SELF-POST rather than inbound mail; do not defeat that by grepping the raw file for your tag.
3. Re-narrow when the crisis ends. The filter is part of the lane, and the lane's close is the filter's close: bash "$CM" stop @<listen-name>.

The honest limit — monitors watch artifacts, not handoffs

A monitor fires on a file changing or a PR state changing. It cannot see two agents waiting on each other. A merge-state watcher on a green PR is silent in exactly the same way whether the reviewer is mid-review or was never routed at all — the silence is a fact about the artifact, never about the handoff. The deadlock in the next section was invisible to every watcher armed at the time, and it was still a deadlock. Use a monitor for the artifact; use closure for the handoff.

Completion → Reviewer Handoff

The live specimen (2026-08-17 retro): the PR #727 implementor sat DONE with an open PR while its lead waited for a collab marker the implementor never wrote. Both agents were behaving correctly and the lane still stalled. The worker had treated "the PR is open and I said so on screen" as delivery.

Worker side

The DONE marker written to the collab is the final write. Not the PR opening. Not a message on screen. Not the report file alone. This is already fleet law (canon #7) and it still failed — so the failure mode is stated beside the rule: a worker that opened its PR, announced it in its pane, and stopped has produced a durable artifact and delivered nothing, because a collab is a mailbox with no doorbell (Participation Law, above). Post the DONE marker, stop your watcher, end the turn — in that order.

Lead side

On a worker's DONE, the lead routes a reviewer. That is not a thing to remember; it is the event the watch exists to deliver. The watch that delivers it is Command 1 above, armed at step 0 on the same collab the worker posts its DONE to. When the NEW-FOR-@<listen-name> line lands carrying that DONE, the routing step is these two commands.

Write the brief to a file first — it carries the PR URL, the head SHA the review is pinned to, and the listen name the reviewer reports to, which is more than a pane-safe inline prompt holds:

gh pr view <number> --json url,headRefOid --jq '"\(.url) @ \(.headRefOid)"'   # the two facts the brief must pin

mcp__cmuxlayer__spawn_agent({
  repo: "<repo>", cli: "claude",
  role: "reviewer", authority: "worker", placement: "right",
  boot_prompt_path: "<absolute path to the review brief you just wrote>",
})

Then append the routing to the collab — reviewer agent_id from the spawn receipt, PR URL, head SHA — so the next lead reads who is reviewing what without a screen read.

closure — the mechanical check

Shipped in cmuxlayer P11 (v0.4.47) and visible at default list_agents detail — no detail:"full" needed:

mcp__cmuxlayer__list_agents({ mine: true })

artifact_missing gates itself. Do not re-gate it on the state the row renders. closure is already derived from done-evidence, not from the live screen. agent-engine.ts:1755 computes effectiveState = isLiveActive(live) ? live.state : agent.state, and isLiveActive (live-agent-state.ts:142) is live.state === "working" && live.source === "screen" — the only live observation strong enough to overturn a recorded done. The AIDEV note above it (agent-engine.ts:1746-1754) states that design outright: "A ready prompt cannot overturn done (a finished worker sits at one too), and a dead/shell pane must not either: there the record's done plus the missing artifact IS the story." So verified and artifact_missing both already mean the record says done, and pending means it does not. The row's state is the raw live observation, and on a finished worker it reads ready — gating on it throws away the exact rows the signal exists to raise. (The record saying done is not proof the worker finished; that is what the three confirm checks below are for.)

Confirm before you route — three checks, all cheap. artifact_missing is a real signal, not a free pass: the fields flap, and a false done detection on a still-running worker produces the same value (#457-rest, below). Before routing, establish all three:

1. The record carries done-evidence. Ask by id — never sweep detail:"full" across the fleet: one full record runs tens of KB, and two of them overflowed a tool-result budget while this section was being written.

   mcp__cmuxlayer__list_agents({ agent_ids: ["<agent_id>"], detail: "full" })

   Want detail.state:"done" with a non-null detail.task_done_detected_at.

2. The live read is not working from screen. That is the only observation the engine itself treats as overriding a recorded done (isLiveActive), and a row rendering it is mid-turn: re-sample, do not route. Every other rendered state — ready above all — is not a veto.

3. The artifact is absent.

   ls -l $HOME/.cmux/agents/<agent_id>/report.md   # detail.report_path

All three → deadlock confirmed, route the reviewer. Any one missing → re-sample instead.

Why not the rendered state, and not the state filter either — live, 2026-08-19, v0.4.47. A 28-row default sweep at 19:21:21Z rendered state:"done" on zero rows, and list_agents({state:"done"}) at 19:22:58Z returned count: 0. A gate requiring either fires on nothing, ever. Seven seconds after that sweep, the two agents it had shown as working/pending read:

list_agents({agent_ids:["<AGENT_ID>","<AGENT_ID>"], detail:"full"})
  <AGENT_ID>  state.value "ready" (source screen)  closure "artifact_missing"
            detail.state "done"  task_done_detected_at 2026-08-19T19:12:35.980Z
  <AGENT_ID>  state.value "ready" (source screen)  closure "artifact_missing"
            detail.state "done"  task_done_detected_at 2026-08-19T19:13:11.903Z
 
$ ls -l $HOME/.cmux/agents/<AGENT_ID>/report.md
ls: ...: No such file or directory
$ ls -l $HOME/.cmux/agents/<AGENT_ID>/report.md
ls: ...: No such file or directory

Two real deadlocks — recorded done, done-timestamp set, contracted artifact absent — that a rendered-state gate discards.

The mechanism, and what is actually the bug. Two things happen here, and earlier revisions of this section each caught only one of them.

By design, not a defect. closure resolves from effectiveState (agent-engine.ts:1897) under the fallback rule above: working/screen takes the live branch → pending; ready/screen does not → falls back to the recorded done → verified or artifact_missing. Every ready specimen above follows it exactly. A previous revision of this doc gated those rows away as noise; they were the true positives.

The actual defect. The state a row renders and the live observation closure was computed from are not guaranteed to be the same sample, so a row can render working/screen — which by the rule must give pending — while carrying artifact_missing. Reproduced live on this agent's own row, 2026-08-19 19:28:46Z, v0.4.47:

list_agents({agent_ids:["<AGENT_ID>"], detail:"full"})
  state.value "working" (source screen, observed 19:28:45.722Z)   closure "artifact_missing"
  detail.state "done"   task_done_detected_at 2026-08-19T19:21:43.047Z
  $ ls -l $HOME/.cmux/agents/<AGENT_ID>/report.md
    No such file or directory

That agent was mid-turn and had written no report: the recorded done was a false detection, and check 2 above is what stops it being routed. The same pair showed on four children in an earlier 25-row default sweep, 2026-08-19:

It is tracked. cmuxlayer #457 (OPEN) names this symptom in its own body — "P11 Contract C closure invariant — VIOLATED. closure:"artifact_missing" on a working agent, at default detail" — and its 2026-08-19T16:57:10Z comment defers "#457-rest", whatever survives PR #466's live-state resolution, because no audit proved the residual gone. #466 merged 2026-08-18, a day before these sweeps, so the residual is current, not historical. The nearby #478 (wait_for/watch) and #473 (wait_for short-circuit) are other call paths.

Neither the closure table nor the confirm step depends on that residual being fixed: checks 1-3 catch it, and stay correct once it is gone.

Sampling note — one clean snapshot refutes nothing. These values flap on live children. <AGENT_ID> read artifact_missing, then verified, with no artifact written in between; a reviewer reproduced a working → done → working flip in 17 seconds; and a later sweep found all four specimens above reading ready/verified at once; and the two voicelayerClaude deadlocks above read working/pending at 19:21:21Z and ready/artifact_missing seven seconds later. Sample twice before you believe either field.

Supervision: Watch, Then Read Once

A supervisor MUST NOT poll read_screen in a loop for one worker outcome. Repeated screen reads are a defect, not diligence: arm a process-exit or background-log watch, let it wake the supervisor, and read the finished screen/log once.

For headless Codex workers, use the codex-workflows skill's watch primitive. It observes process exit first and parses the completed log once. For this monitor, keep follow attached to the supervisor's monitored long-running command session; do not replace it with repeated screen inspection.

Routing Grammar

The filter is tag-scoped and anchored on both sides of a mention, so email-like text such as owner@listener does not route. For routed headings, only mentions in the recipient field between the arrow and event-summary separator qualify; a listener mentioned later in the summary is not a recipient. It accepts:

• a routed Markdown header such as ### @author → @your-listen-name — event;
• a direct line beginning @your-listen-name: or → @your-listen-name, with the arrow form followed by end-of-line or a :, -, or — separator.

A direct line at the end of a file is held until a standalone trailing author signature (— @author or -- @author) or later heading closes its message block. Contextual dash lines and signatures that merely cc the listener do not close or classify a block. This prevents a split write from alerting before a self-author signature arrives. A block authored by the listen name—either before the routing arrow in its header or in a trailing — @your-listen-name signature—is classified as SELF-POST rather than emitted as inbound NEW-FOR mail. A recognized foreign signature overrides an earlier self-authored heading so nested inbound mail remains visible.

Prose that merely contains the tag, TASK_DONE, error, failed, PR, or done is not an event. If a post matters to a listener, address it using the routing grammar.

Fenced and indented code is excluded from routing, so examples of the grammar do not wake the monitor, including four-space fenced blocks nested beneath a Markdown list item and fences opened directly on a list-marker line. Backtick markers whose info remainder contains another backtick are treated as inline content, not as fence openers. A four-space routed reply immediately nested beneath a list item remains prose and can route normally. An unclosed fence emits WATCH-WARN reason=unclosed-fence, makes the poll incomplete, and is retried until the fence closes; start does not publish readiness while that condition exists.

Guarantees

1. Silent seed: current matching history is hashed without alerting when a file is first watched.
2. Content-hash dedup: a previously seen event line does not re-fire when any watched file grows or identical content is appended to another watched file for the same listen name. If the seen-set disappears or becomes unreadable after size baselines exist, the poll fails closed with reason=state-failed instead of replaying history.
3. Self-classification: self-authored routed headers and trailing-signature blocks emit a distinct SELF-POST record, never a normal inbound alert.
4. Shrink detection: a byte-size decrease emits a distinct SHRINK record with its byte delta.
5. Bash 3.2 safety: state lives in ordinary files; the implementation uses neither declare -A nor comm.
6. Durable lifecycle: start reports success only after the detached runner completes its first seed/poll, allowing 30 seconds by default for a large healthy historical seed, and records a validated PID plus per-start instance identity by listen name; an interrupted pre-readiness start terminates and reaps its unpublished runner, duplicate starts fail, ambiguous live-PID conflicts preserve their state for recovery instead of signaling or orphaning a process, stop never signals a stale/reused PID or a same-name monitor from another state root, and a zombie runner is treated as stopped instead of timing out.
7. Stable path identity: relative and absolute spellings resolve to one size-state record, so a spelling change cannot silently re-seed a file.
8. Transient-file retry: a watched path that temporarily vanishes or fails mid-read emits WATCH-WARN and is retried without killing the foreground monitor; run --once reports the incomplete poll with a non-zero exit.
9. Code-example exclusion: fenced and indented code cannot impersonate routed mail; an unclosed fence is an explicit incomplete poll rather than silent event loss.
10. Attached alert consumption: follow streams the current start session's log to the orchestrator and exits after that named monitor stops; detached start output alone is never presented as a wake mechanism.

Delivery is at-least-once. The monitor emits an event before atomically persisting its hash and then updating the file-size baseline. A crash at that boundary can duplicate the last alert, but does not intentionally mark an un-emitted alert as delivered.

Output

MONITOR-ARMED name=@listener files=2 state=/.../listener
WILL-NOT-CATCH :: ...
FOLLOWING name=@listener pid=<pid> log=/.../monitor.log
NEW-FOR-@listener file=/path/collab.md hash=<sha256> :: <literal event line>
SELF-POST-@listener file=/path/collab.md hash=<sha256> :: <literal own-write line>
SHRINK file=/path/collab.md old_bytes=123 new_bytes=80 delta_bytes=43
WATCH-WARN file=/path/collab.md reason=temporarily-absent|read-failed|hash-failed|state-failed|unclosed-fence action=retry
STATE_CONFLICT name=@listener pid=<pid> action=not-started|not-signaled state=preserved

State defaults to ~/.local/state/collab-monitor/<listen-name>/; the special path names . and .. are rejected. Set MONITOR_STATE_DIR only for isolated tests or a deliberately managed alternate state root. Set POLL_SECONDS to a positive integer or decimal to change the foreground/background polling interval. start waits up to 30 seconds for the initial seed/poll; set START_TIMEOUT_SECONDS to a positive whole number no greater than 86400 when a very large or slow board needs a longer readiness deadline. Zero and malformed polling or startup values fail before run or start arms, while status and stop remain available for recovery.

On STATE_CONFLICT, inspect the preserved PID, instance, readiness, and run-lock records before retrying; do not delete state or signal the PID until its command and per-start identity are verified.

What This Will Not Catch

The runner prints these limits on every arm because silence is not full safety:

• same-size rewrites in place; growth rewrites trigger a scan but may look like appends;
• messages outside the anchored routing grammar;
• unclosed trailing direct messages, which are held until a signature or later heading closes the block;
• inbound direct mail nested in a self-authored block remains self-classified unless a recognized foreign signature closes it;
• process death without an external supervisor;
• worker completion represented only in an agent registry.

Use a tamper/file-integrity monitor for rewrite detection and registry polling for worker completion. This skill is the addressed-message channel, not either of those systems.

One further limit the runner cannot print, because it is not a property of any watched file: a monitor cannot see two agents waiting on each other. See "The honest limit" above, and use the closure field for handoff state.

Migration

Until the external orchestrator caller is migrated, this skill is the implementation source of truth. The PR that introduced it proposes turning orchestrator/scripts/collab-monitor.sh into a thin compatibility caller rather than maintaining a second monitor implementation.

Evaluation

Run:

bash skills/golem-powers/collab-monitor/evals/run-evals.sh candidate
bash skills/golem-powers/collab-monitor/evals/live-two-file-smoke.sh

The deterministic suite covers the recorded monitor failures, /large-plan's exact broken grep done teaching repro, addressed completion/blocker teaching in linked workflows, rejection of repeated read_screen supervision, code-example exclusion and malformed-fence recovery, shrink detection, limitations disclosure, durable lifecycle safety at the shipped poll interval, exact listen-name boundaries, path identity, and transient-file retry.