loop-cron

Loop-Cron Wiring

Claude Code's built-in /loop skill drives periodic work via CronCreate. On its own, those loops are invisible to other terminals — you can't see what's scheduled, can't tell when one last ran, and can't pause them without killing the process. Empirica's loop registry fixes that with three CLI calls layered into the cron prompt.

This skill is the prompt template for cron-mode loops that integrates with the registry.

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When to Use

You're about to start a cron-mode loop with /loop (or already have one running) and:

• You want it visible in empirica status --all
• You want to pause/resume from any terminal without killing the process
• You want a heartbeat trail for "did it actually run, did it succeed"
• You want it to survive a Claude Code session restart cleanly

If your loop is one-shot or interactive ("dynamic mode"), skip this — it applies to scheduled (cron/interval) loops only.

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Cron Prompt Template (self-scheduling)

Per PROPOSAL_LOOP_SELF_SCHEDULING.md: the body owns the schedule. Each fire installs the next fire as a one-shot at the timestamp the backoff math returns. There is no recurring cron — pause means the scheduler is silent (no token bleed).

When invoking /loop in cron mode, prepend these CLI lines to your task prompt. Variables: {NAME} (loop identifier, no spaces), {INTERVAL} (base cadence, e.g. 15m), {DESC} (one-line description).

At start (idempotent — safe to call every fire):
  empirica loop register --name {NAME} --kind cron --interval "{INTERVAL}" \
    --description "{DESC}" \
    --backoff exponential --base-interval {INTERVAL} --max-interval 4h

Check pause — exit silently AND don't schedule next fire if paused:
  PAUSED=$(empirica loop status {NAME} --output json | jq -r .paused)
  if [ "$PAUSED" = "true" ]; then
    empirica loop heartbeat {NAME} --status ok --result paused \
      --message "skipped, paused"
    exit 0   # CRITICAL: exit without scheduling next; loop is genuinely off
  fi

[... your actual work here, capturing $RESULT as found|empty|fail ...]

At end — heartbeat with result, then schedule + install the next fire:
  empirica loop heartbeat {NAME} --status ok --result $RESULT \
    --message "$SUMMARY"

  NEXT_CRON=$(empirica loop schedule-next {NAME} --output json | jq -r .cron_one_shot)

  # Install the next one-shot using your scheduler:
  # Claude Code:    CronCreate(cron=$NEXT_CRON, recurring=false,
  #                            prompt='<this whole template again>')
  # systemd-user:   systemd-run --user --on-active=$INTERVAL ...
  # at-queue:       echo '<command>' | at -t $(date -u -d "$NEXT_FIRE" +%Y%m%d%H%M)

  # Then heartbeat back the scheduler-returned job_id so pause can cancel:
  empirica loop heartbeat {NAME} --status ok --result $RESULT \
    --next-scheduled-job-id "$JOB_ID" --scheduler-kind cron-create

On failure:
  empirica loop heartbeat {NAME} --status fail --result fail \
    --message "{error}"
  # Failure retries at base — schedule-next still returns base interval.