Agent Self-Scheduling

Make an agent run periodically. First question: does the agent have a built-in scheduler, or do you own the clock?

Decision: pick the camp first

• Need it NOW, agent has no scheduler, or sub-minute polling → Camp A (external clock).
• Want managed recurring jobs, isolated sessions, chaining, loop safety → Camp B (Hermes built-in).

Universal floor: ALL cron is 1 minute (5-field expr, no seconds) — every camp. For sub-minute / sub-second you MUST use a dumb while ...; sleep N; done loop, a TS extension, or a webhook/event hook. Never put an LLM on a tight timer.

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Camp A — One-shot agents, you own the clock

These run once and exit (amnesiac unless resumed). You schedule them externally.

One-shot invocations:

claude -p "PROMPT" --output-format json --allowedTools "Read,Edit,Bash"  # Claude Code
codex exec --json "PROMPT"                                                # Codex
pi run "PROMPT"                                                           # Pi.dev (Mario Zechner; MIT; read/write/edit/bash + TS SDK)

Wrap in a clock — three options:

# 1. cron (>= 1 min). Floor is 1 minute, 5 fields, NO seconds.
*/10 * * * * cd /path/to/project && pi run "check X and report" >> ~/agent.log 2>&1

# 2. systemd timer (Linux, survives reboot, better logging) — OnUnitActiveSec=10min

# 3. dumb loop (sub-minute, or when cron unavailable)
while true; do pi run "check X"; sleep 30; done

Camp A gotchas (all three break unattended runs if ignored):

• Permissions block unattended runs. Pass --allowedTools (Claude) or a sandbox/auto-approve flag (Codex) or the run hangs on a prompt forever.
• Use structured JSON output, not prose (--output-format json / --json) so the wrapper can parse the result deterministically.
• Each run is amnesiac. No memory across runs unless you resume: codex exec resume --last. Otherwise persist state to a file the next run reads.

Pi specifics: Pi has NO built-in loop/scheduler/heartbeat by design — only the agent reasoning loop (not time-based). OpenClaw's runtime is built ON Pi but is a separate project. To schedule Pi: external cron/systemd, a while-sleep loop, or a TS extension for agent-side timers.

cmux (orchestration layer — NO scheduler)

cmux has NO scheduler/timer/watch/cron. It is visibility + orchestration only. Primitives: list-workspaces, read-screen (non-interruptive — safe to poll), send. An MCP wrapper cmux-agent-mcp exists.

Three ways to make cmux loop:

• Orchestrator-driven — the orchestrator runs send → sleep → read-screen on its own clock.
• Dumb wrapper — external while true; ...; sleep N; done.
• Event-driven (preferred over polling) — use cmux notify + OSC 9/99/777 terminal hooks so work fires on a real signal instead of a timer. Cheaper and more responsive than read-screen polling.

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Camp B — Hermes (built-in scheduler daemon)

Hermes ships a gateway that ticks every 60s and runs due jobs in fresh, isolated sessions. No external cron needed.

State-check first — is the gateway running?

hermes gateway install            # user-level
hermes gateway install --system   # survives reboot (boot-time)

Create jobs (CLI or /cron add in TUI):

hermes cron create "every 1h" "summarize new emails and report" --skill himalaya
hermes cron create "0 9 * * *" "post daily standup"      # cron expr
hermes cron create "30m" "one-shot reminder in 30 min"   # one-shot delay

Schedule formats: one-shot delays (30m, 2h), recurring (every 30m, every 1d), cron (0 9 * * *), ISO timestamps.

Hermes-unique capabilities:

• Zero-token / no-agent mode — run a script on schedule, deliver its stdout verbatim. No LLM cost. Use for watchdogs/heartbeats where the script produces the exact message.
• Chaining — context_from injects an upstream job's last output into a downstream job; combine with a working dir to pipeline jobs.
• Self-terminating loops — a recurring job can stop itself when a condition is met.
• Fresh self-contained sessions — each run starts clean; the prompt must carry all needed context (no chat history).
• Loop safety — cron-run sessions CANNOT create more cron jobs (prevents runaway recursion). Don't try to schedule from inside a scheduled job.
• Persistent /goal loop — long-running autonomous loop with pause/resume, separate from cron.

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Heartbeat pattern (proactive self-check)

A heartbeat = a fast recurring tick that gates slower per-task checks, so one loop handles many intervals at different cadences.

• In Camp B: a recurring Hermes job (e.g. every 5m) whose prompt/script checks a task list and only acts on tasks whose own interval is due. Use no-agent mode + a script for zero token cost when nothing's due.
• In Camp A: same idea via a while-sleep loop that reads a tasks file and per-task last_run timestamps.
• Save tokens: define active-hours and skip ticks outside them; skip the tick entirely when there's nothing due (stay silent — don't emit empty noise).

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Verify it actually fires (do this before reporting success)

1. Camp A: check the log file grows after one interval, or run the wrapped command once by hand and confirm clean JSON exit (0).
2. Camp B: hermes cron list shows the job; check next_run; trigger once with a run-now to confirm it executes and delivers.
3. Confirm permissions/sandbox flags are present (Camp A) — the #1 silent failure is a hung permission prompt.
4. For heartbeats, confirm a tick with nothing-due stays silent (no spam).

Pitfalls

• Cron CANNOT do sub-minute. Don't promise every 30s via crontab — use a loop.
• Camp A unattended hangs without explicit tool allowlists / sandbox.
• Don't schedule a job from inside a scheduled Hermes job (loop safety blocks it).
• Each scheduled run is a fresh/amnesiac session — pass all context in the prompt or persist to a file.