The counter that counts itself

pgrep -f my-service inside the watchdog itself matches the shell running the command. The guard sees 1 process, concludes “alive”, and never restarts anything — including when the service is dead.

Better: scan /proc/<pid>/cmdline excluding $$ and $PPID, and confirm with a second signal (log age, service state).

Zero is not health

A session guard reporting active_chats=0 is either saying “nothing to do” — or “I am reading the wrong database”. If three groups are talking and the guard counts zero, that number is a symptom, not peace of mind.

Before trusting a zero, confirm the source: is the file the guard reads the same one the process writes? A store with 0 rows keeps the guard green forever.

A fixed gate on an oscillating machine

A fixed memory floor (say 4,600 MB) on a machine that measures 10,800 MB and 4,100 MB minutes apart blocks half the runs — and you blame the service.

Size the gate by the minimum observed with explicit headroom (one task = 400-800 MB → a 2,000 MB floor gives 2.5x). Measure twice, minutes apart, before picking the number.

A lost delivery looping

Dedup by text hash resends the same message every time the text changes — and the text changes each tick, because the agent keeps working. Result: the group gets the same notification several times.

A lost delivery is one event: dedup by (channel, ready_timestamp), and store the key even when the resend fails — otherwise it repeats forever.

How to prove a guard works

1. Negative test, mandatoryForce the condition (kill the service, empty the source, delay the delivery) and verify the guard fires. A guard that never failed a forced test has no evidence of working.
2. Log a verdict per tickWithout a log line per run, “green” is faith. The log must say what was measured and what was decided.
3. Delivery proofAn alert that does not arrive is an alert that does not exist: demand the delivered message id, not the script's exit code.

See the Roger MLOps Guard skill See all skills

Want this wired into your project? Guided setup from R$ 1.500, with the first cycle run together.