Schedule recurring tasks and heartbeat monitoring using Claude Code's cron system (CronCreate/CronList/CronDelete). Implements the Agentic Heartbeat Pattern for ecosystem health monitoring.
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Schedule recurring tasks and heartbeat monitoring using Claude Code's cron system (CronCreate/CronList/CronDelete). Implements the Agentic Heartbeat Pattern for ecosystem health monitoring.
category
infrastructure
trigger
when user wants recurring tasks, scheduled maintenance, heartbeat monitoring, periodic health checks, cron jobs
The primary user-facing way to invoke scheduled tasks is via the /loop command. This is the
recommended interface for most users.
Syntax
/loop <interval> <prompt> # interval-based
/loop every 5m <prompt> # explicit "every" syntax
/loop 2h <prompt> # shorthand hours
/loop at 8:00am <prompt> # time-based (daily at local time)
Common Intervals
2m, 5m, 10m, 15m, 30m # minutes
1h, 2h, 4h, 6h, 12h # hours
at 8:00am, at 3:00pm # daily time triggers (local timezone)
Examples
/loop 5m Check for new Telegram messages and reply
/loop 2h Distill recent session learnings into .claude/context/memory/learnings.md
/loop at 8:00am Read issues.md and CHANGELOG.md and give morning briefing
/loop every 4h Run pnpm search:code "indexing" to refresh codebase index
/loop 30m Heartbeat: read agent-health.json, check memory sizes, TaskList for stuck tasks
Chaining: Run a Slash Command on a Schedule
/loop 20m /review-pr 1234 # run a slash command on a schedule
/loop 2h /heartbeat-start # restart heartbeat ecosystem every 2 hours
Key Behaviors
Behavior
Detail
Jitter
Tasks fire up to 10% of their period late (max 15 min) — avoids stampedes
No catch-up
Missed fires are NOT replayed after sleep/hibernation
Session-scoped
Loops stop automatically when the Claude Code session ends
Local timezone
at HH:MMam/pm triggers use local time, not UTC
Max 50 loops
Hard cap of 50 concurrent scheduled tasks per session
3-day expiry
All loops silently self-delete 3 days after creation (reschedule before day 2.5)
Fire-between-turns
Tasks fire only when Claude is idle, not mid-response
Heartbeat OS Pattern
Use /loop to build a self-improving agent ecosystem that runs continuously in the background:
Continuous Reflection (every 2h)
/loop 2h Read .claude/context/memory/issues.md and recent session context. Extract patterns, workarounds, and decisions. Append to learnings.md and decisions.md.
Autonomous Evolution (daily at 3am)
/loop at 3:00am Review learnings.md and test failures. Use agent-updater skill to improve agent .md files. Run pnpm validate:full before finalizing.
Morning Briefing (weekdays at 8am)
/loop at 8:00am Read CHANGELOG.md and issues.md. Summarize technical debt, flaky tests, and top 2 tasks for today.
Context Drain (every 15m)
/loop 15m Check if all tasks are done. If TaskList shows zero in_progress tasks, summarize session to memory and surface readiness for /clear to user.
Codebase Indexing (every 4h)
/loop 4h Run pnpm code:index:reindex to refresh the BM25 and semantic search index.
Start the Full Heartbeat Ecosystem
Use /heartbeat-start to launch all 7 loops in one command. See .claude/commands/heartbeat-start.md.
Overview
Provides patterns for scheduling recurring tasks using Claude Code's built-in cron system (CronCreate/CronList/CronDelete). Also implements the Agentic Heartbeat Pattern for keeping the agent ecosystem healthy.
Core distinction:
Cron tasks: "Run this SPECIFIC task at 3am Tuesday" — deterministic, time-anchored maintenance
Heartbeat: "Check in periodically; act IF something needs attention" — awareness-based, conditional liveness
Decision Framework: When to Use Cron
Quick Decision Checklist (run through before calling CronCreate)
Is the task recurring? If NO → use TaskCreate instead (cron is for recurring work only).
Can it tolerate up to 15-minute jitter? If NO → use OS cron or GitHub Actions (CronCreate has built-in jitter).
Is it acceptable to lose it on terminal close? If NO → use OS cron (crontab -e) or GitHub Actions for persistence.
Will it complete within the session? If the session may end before the task fires → prefer OS-level scheduling.
Is it for monitoring/health checks? If YES → CronCreate is the right tool (this is its primary use case).
Are there 10+ other cron tasks already scheduled? If YES → reconsider; stay under 10 concurrent tasks (50-cap headroom).
Decision Tree
Need a recurring task?
├── NO → Use TaskCreate (one-shot) or Task()
└── YES
├── Must survive terminal close?
│ ├── YES → Use OS cron (crontab -e) or GitHub Actions
│ └── NO (session-scoped is fine)
│ ├── Time-critical (< 15 min precision required)?
│ │ ├── YES → Use OS cron or GitHub Actions
│ │ └── NO → CronCreate is appropriate ✓
│ └── Is it monitoring/heartbeat?
│ └── YES → CronCreate is ideal ✓
Periodic index rebuilds during an active work session
Scheduled memory rotation checks while actively developing
Auto-reschedule tasks that keep other cron tasks alive
Morning briefings and context-drain checks during sessions
When to Use OS Cron / GitHub Actions Instead
Tasks that must run even when Claude Code is not open
Production scheduled jobs (backups, deployments, data pipelines)
Tasks requiring sub-minute precision or hard time guarantees
Any task where silent expiry (3-day limit) is unacceptable
When NOT to Use CronCreate
One-time tasks (use Task or TaskCreate)
Tasks triggered by events rather than time (use hooks or event listeners)
Tasks requiring external system persistence across Claude restarts
Time-critical alerts where 15-minute jitter is unacceptable
Session-Scope Context Note
CRITICAL — Session-Scoped Loops: All CronCreate loops are registered to the current Claude Code session and are permanently lost when the session ends (terminal close, /clear, or session restart). After any session restart, all loops must be re-registered manually.
heartbeat-orchestrator handles this automatically. When the heartbeat ecosystem is running, heartbeat-orchestrator is responsible for detecting missing loops after session restarts and re-registering them. If you are not using heartbeat-orchestrator, you must re-register all loops yourself at the start of each new session.
To check which loops are active: CronList(). If loops are missing after a restart, re-run the setup commands or invoke /heartbeat-start.
Quick Reference
// Schedule a recurring taskCronCreate({ schedule: '*/30 * * * *', task: 'heartbeat check prompt' });
// List active cron tasksCronList();
// Remove a scheduled taskCronDelete({ id: 'abc12345' });
Constraints (CRITICAL — Read Before Using)
Constraint
Detail
Session-scoped
All cron tasks die when the terminal closes — no persistence across restarts
50-task cap
Maximum 50 concurrent scheduled tasks per session
3-day auto-expiry
Recurring tasks self-delete 3 days after creation (SILENT — must reschedule before day 2.5)
Fire-between-turns
Tasks fire only when Claude is idle, not mid-response
No catch-up
Missed fires are NOT replayed — task fires once at next idle opportunity
Jitter
Tasks fire up to 10% of their period late (max 15 min) to avoid API stampedes
Timezone
All cron expressions use local system timezone, NOT UTC
No extended syntax
L, W, ?, name aliases like MON are NOT supported
Cron Expression Reference
Standard 5-field syntax: minute hour day-of-month month day-of-week
Expression
Meaning
*/30 * * * *
Every 30 minutes
*/5 * * * *
Every 5 minutes
0 * * * *
Every hour on the hour
0 2 * * *
Every day at 2am local
0 3 * * 0
Every Sunday at 3am
0 6 * * 1-5
Weekdays at 6am
0 0 */2 * *
Every 2 days at midnight
Heartbeat Pattern
Design Philosophy (OpenClaw-inspired)
Cheap file reads FIRST, LLM only when needed. Achieve 60-80% cost reduction for healthy-state ticks.
Execution model:
Heartbeat fires at scheduled interval
Read HEARTBEAT.md checklist (cheap file read — no LLM call)
If blank/headers-only → emit HEARTBEAT_OK immediately, no LLM invocation
Read cheap signals (file sizes, agent-health.json, task list) — still no LLM
If ALL signals green → emit HEARTBEAT_OK
Only if signals indicate issues → invoke LLM with full HEARTBEAT.md context
Heartbeat Checklist
Check these signals on each heartbeat tick (in order — cheapest first):
Agent health: Read agent-health.json — any agents status: degraded?
Memory sizes: Is learnings.md > 40KB? Is decisions.md > 80KB?
Stuck tasks: TaskList() — any tasks in in_progress for > 2 hours?
Hook errors: Any hooks with errorRate > 0.05 in agent-health.json?
Reflection queue: Does reflection-reminder.txt exist and is stalled?
BM25 freshness: Is index mtime > 24 hours?
If ALL healthy → return HEARTBEAT_OK (no further LLM invocation needed)
If ANY unhealthy → spawn appropriate agent to fix, then report
HEARTBEAT.md Template
Create HEARTBEAT.md in the project root as standing instructions for the heartbeat:
# Agent Studio Heartbeat Checklist## Every Tick (30 minutes)### Memory Health- [ ] learnings.md > 40KB? → trigger rotation via node .claude/lib/memory/memory-rotator.cjs
- [ ] decisions.md > 80KB? → warn user
- [ ] issues.md has unresolved P0 items? → surface to user
### Agent Registry Health- [ ] agent-health.json has any status: degraded? → alert
- [ ] Any hooks have errorRate > 5%? → alert with hook name
### Task Health- [ ] Any tasks stuck in in_progress for > 2 hours? → surface task IDs
### Reflection Queue
- [ ] reflection-reminder.txt exists? → alert (reflection queue stalled)
## Self-Maintenance
- [ ] This heartbeat task older than 2.5 days? → reschedule before 3-day expiry
Scheduled Maintenance Patterns
Index Rebuild (nightly)
CronCreate({
schedule: '0 2 * * *',
task: 'Rebuild BM25 search index for code discovery. Run: cd /project && pnpm code:index:reindex',
});
Memory Rotation Check (weekly)
CronCreate({
schedule: '0 3 * * 0',
task: 'Check memory file sizes and rotate if needed. Run node .claude/lib/memory/memory-rotator.cjs and report results.',
});
Agent Registry Refresh (daily)
CronCreate({
schedule: '0 6 * * *',
task: 'Regenerate agent registry: pnpm agents:registry and verify 72 agents are registered.',
});
Auto-Reschedule (every 2 days — prevents 3-day silent expiry)
CronCreate({
schedule: '0 0 */2 * *',
task: 'Re-register all scheduled tasks to prevent 3-day auto-expiry. Call CronList() to check what tasks exist, then recreate any that are missing or older than 2.5 days.',
});
Reschedule a Specific Task (correct order — no scheduling gap)
When replacing a running cron task with updated settings, ALWAYS use CronCreate FIRST, then CronDelete.
This prevents a scheduling gap where no cron task exists between delete and create.
// CORRECT ORDER: Create new before deleting old to prevent scheduling gap// Step 1: Create the new task FIRST (new task is now running)CronCreate({
schedule: '*/30 * * * *',
task: 'Updated heartbeat prompt with new checks.',
});
// Step 2: THEN delete the old task (old ID obtained from CronList())// There is never a window where no heartbeat cron existsCronDelete({ id: 'old-task-id-from-cronlist' });
// WRONG ORDER (creates a scheduling gap — do NOT do this):// CronDelete({ id: "old-id" }); // <-- gap begins here// CronCreate({ ... }); // <-- gap ends here (tasks missed during gap)
Weekly Validation (every Sunday)
CronCreate({
schedule: '0 3 * * 0',
task: 'Run full framework validation: pnpm validate:full and report any errors found.',
});
