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Cloudflare Workers Cron Trigger monitoring with RunVouch

Cloudflare Workers Cron Trigger monitoring where there is no exit code: a Worker's scheduled() handler has no output you can look at later and, on the free plan, a CPU time limit that ends a run mid-way without an error you will see.

How it runs on Cloudflare Workers Cron Triggers

Inside scheduled(event, env, ctx), with two fetch() calls to the API. Workers cannot run a binary.

Store the key

wrangler secret put RUNVOUCH_KEY; read it as env.RUNVOUCH_KEY.

Report the run (two HTTP calls)

export default {
  async scheduled(event, env, ctx) {
    const h = {"X-API-Key": env.RUNVOUCH_KEY, "content-type": "application/json"};
    const {run_id} = await (await fetch("https://api.runvouch.com/v1/runs/start", {method: "POST", headers: h,
      body: JSON.stringify({agent: "nightly-report", source: "cloudflare"})})).json();
    let status = "ok", evidence = {};
    try { evidence = {rows: await doTheWork(env)}; } catch (e) { status = "fail"; }
    ctx.waitUntil(fetch("https://api.runvouch.com/v1/runs/end", {method: "POST", headers: h,
      body: JSON.stringify({run_id, status, evidence})}));
  }
}
// wrangler.toml:  [triggers]  crons = ["0 2 * * *"]

The start call returns run_id; the end call takes status (ok or fail), optional cost and tokens, and evidence as a JSON object of booleans. Full reference on the API page.

Register the cadence and caps

rv agent nightly-report --cadence 24h --grace 30m --max-runtime 1h --evidence --cap-run-cost 2

Register the agent once, from anywhere with the key. Cadence is what turns a schedule that stopped into an alert; --evidence makes a run without evidence a failure; the caps pause the agent when it overspends.

What goes silent on Cloudflare Workers Cron Triggers

• A cron trigger removed from wrangler.toml on the next deploy stops silently; MISSED is the only signal.
• Exceeding CPU time kills the invocation; the start call already happened, so RunVouch marks the run STALLED when it never ends.
• An await that is not wrapped in ctx.waitUntil can be cut off; put the end call in waitUntil as above.

What Cloudflare Workers Cron Triggers does not tell you

The Cloudflare dashboard lists past cron invocations per Worker with a status and duration; there is no notification when an invocation fails, is cut off by the CPU limit, or stops being scheduled because the [triggers] block was dropped from wrangler.toml in a deploy. Console output is only kept if you enable Workers Logs or tail the Worker live.

What RunVouch detects

Set up in two minutes

1. Get a free key (3 agents, no card) and store it where this page says.
2. report the run (two http calls): copy the snippet above into the scheduled job.
3. Register the cadence once: rv agent nightly-report --cadence 24h --grace 30m --evidence, or let the first run create the agent and set the cadence on the dashboard.
4. Send one test alert: curl -X POST https://api.runvouch.com/v1/settings/test-alert -H "X-API-Key: $RUNVOUCH_KEY". The next missed, failed or empty run reaches the same channels.

Also running cloud functions?

Vercel Cron Jobs. Supabase (pg_cron + Edge Functions). AWS Lambda + EventBridge Scheduler. Google Cloud Scheduler. The full list of runtimes is on integrations, and the same agent can report from several of them: one job, one cadence, wherever it happens to run.

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