@parke.dev/pi-sentinel

Criteria-gated wakeups for the Pi coding agent. Sentinel polls shell probes without spending model tokens, wakes the agent only on meaningful transitions, and prevents babysitting tasks from being declared complete before their criteria pass.

Tool	What it does
sentinel_watch	Poll a command until it passes, changes, or times out
sentinel_sleep	Wake after a duration or at an ISO-8601 time
sentinel_gate	Require every session criterion to pass, optionally for a quiet time
sentinel_status	Show watches, sleeps, gate state, output snippets, and poll ETAs
sentinel_cancel	Cancel one sentinel, the gate, or everything

Install

pi install npm:@parke.dev/pi-sentinel

No configuration is required.

Predicates

A command passes by default when it exits 0. done_when and pass_when can instead use exactly one small predicate:

{ "exit_code": 2 }
{ "output_contains": "ready" }
{ "output_json": { "path": "checks.pending", "equals": 0 } }

JSON paths are dot-separated object keys. Put arrays, comparisons, and other complex logic in the command itself with tools such as jq, then use the command's exit code as the predicate.

sentinel_watch polls every 60 seconds by default. Set wake_on_change to wake when stdout changes, or timeout_s to expire and wake instead of silently stopping. Each command invocation is killed after 30 seconds so a hung probe cannot wedge the scheduler. Polls run only while the agent is idle and are rechecked when it settles.

Completion gates

A gate passes when every criterion passes and, if quiet_for_s is set, remains passing for that whole window. The agent is woken for pass/fail flips and for a clear SENTINEL GATE: ALL PASS transition. While a gate is open, its task is not done.

See the bundled sentinel skill for a PR babysitting recipe covering CI, unresolved review threads, and a ten-minute quiet window.

Lifecycle

Sentinels are session-scoped and in-memory. They are removed on session shutdown or reload and do not survive a Pi restart. Persistent restoration may be added in a future version.

Probe output is capped before being sent to the model, retaining both the head and tail. The footer status and editor widget show active watches, sleeps, and gate progress.

License

MIT