Loop

Overview

loop.mjs is a dependency-free Node ESM runner that registers and fires codex exec jobs on a fixed interval. It manages task state in .codex/loop/ and exposes 8 subcommands: parse-loop, add, list, cancel, status, run-due, daemon, doctor.

It supports only the interval-repeat (loop) task kind. For cron schedules or a one-shot run at a specific time, use the separate schedule skill instead.

Durable Always-On: Use Automations First

Codex app Automations is the official, always-on surface for durable recurring runs — recommend it first. It persists across reboots and terminal exits without a running process.

The bundled local CLI is a terminal fallback only: nothing fires unless the daemon process is running. It is NOT an OS service and does not survive terminal exits.

Local Fallback Usage

All state-mutating commands require --state-root <dir>. Conventional path: --state-root .codex/loop.

Add a loop task

User says /loop 1m check CI status:

node scripts/loop.mjs add \
  --state-root .codex/loop \
  --interval 1m \
  --prompt "check CI status" \
  --cwd "$PWD"

• add is loop-only: --kind is optional and, if given, must be loop.
• parse-loop validates a /loop [interval] <prompt> spec and returns JSON without writing state.
• Default interval when omitted: 10m. Units: s (rounds up to nearest minute, min 1m), m, h, d.
• Optional --next-run-at <ISO> overrides the first computed run time (testing/backfill).

Manage tasks

# list all tasks (append --json for machine-readable output)
node scripts/loop.mjs list --state-root .codex/loop

# cancel one task
node scripts/loop.mjs cancel <id> --state-root .codex/loop

# cancel all active tasks
node scripts/loop.mjs cancel --all --state-root .codex/loop

# show task counts and lock state (append --json for JSON output)
node scripts/loop.mjs status --state-root .codex/loop

Start the runner

node scripts/loop.mjs daemon \
  --state-root .codex/loop \
  [--poll-ms 5000]       # check interval in ms, default 5000
  [--once]               # run one poll pass then exit
  [--max-runs N]         # exit after N total task fires
  [--codex-bin /path/to/codex]

The daemon holds a single-runner lock (scheduled_tasks.lock/). A second daemon against the same state root fails while the first is alive and reclaims only a provably stale lock (dead PID).

run-due does one on-demand due-check pass without occupying the daemon lock continuously — useful for CI triggers or manual testing. It accepts the same --codex-bin and repeatable --codex-arg flags.

Verify setup

node scripts/loop.mjs doctor --state-root .codex/loop

Checks state-root writeability, task count, lock state, and codex binary reachability. It is read-only and never creates the state root.

Daemon Requirement

Nothing fires unless daemon (or run-due) is running. Keep the daemon in a persistent terminal or tmux session. It exits cleanly on SIGINT/SIGTERM, releasing the lock.

After each run, a loop task's next run is recomputed as finishedAt + intervalMs, so the interval is measured from run completion and never drifts.

Run Evidence

Each task run is recorded under .codex/loop/runs/<taskId>/ with timestamped .jsonl (full codex stdout), .last.txt (last Codex message), and optionally .stderr.txt files.

Safety Defaults

• --codex-arg pass-through uses a default-deny allowlist: only a small, vetted set of flags that cannot weaken the sandbox, approval policy, or config is permitted — currently --model/-m (with its value). Every other flag is rejected with a ValidationError naming the arg. This explicitly rejects sandbox/approval/config overrides such as --sandbox/-s danger-full-access, --config/-c ..., --ask-for-approval/-a never, --full-auto, --profile, --dangerously-bypass-approvals-and-sandbox, and --yolo (in both space- and =-joined forms). Args are additionally constrained to the [-A-Za-z0-9_.,:=/@+] character set.
• Allowed pass-through args are inserted before the - stdin sentinel so codex parses them as flags and still reads the prompt from stdin.
• The script never emits approval- or sandbox-bypassing flags to codex exec.
• Does not install OS cron, launchd, or any system service.

Reference

Read references/loop-contract.md for the full state/lock schema, interval grammar specification, and complete per-command contracts.