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cron-and-intervals

cron-and-intervals

github.com/val-townDevelopment1041 installsUpdated 5w ago
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About cron-and-intervals

A Val Town skill for creating and managing interval vals that run on cron schedules. It helps developers handle recurring jobs, account for UTC scheduling, and test handlers manually.

Key features

  1. 01Define recurring jobs with cron expressions
  2. 02Use the previous successful run timestamp
  3. 03Read, update, pause, or resume schedules
  4. 04Run handlers manually for verification

Use cases

  1. 01Poll external APIs on a schedule
  2. 02Send reminders or generate reports
  3. 03Process only items added since the last run

Install

Copy the command and run it in a terminal.

$npx skills add https://github.com/val-town/plugins --skill cron-and-intervals

After installing, type/cron-and-intervalsin Claude Code to confirm it loaded.

Details

From the project README

Cron / Interval Vals

Interval vals (fileType: "interval") run on a recurring schedule defined by a cron expression. Use them for polling external APIs, sending reminders, running cleanups, generating reports, or any work that should happen on a clock rather than in response to a request.

Basic handler

// Learn more: https://docs.val.town/vals/cron/
export default async function (interval: Interval) {
  // interval.lastRunAt: Date | undefined
  console.log(interval);
}

The file must have an export — export default for the handler.

Timezone

Cron expressions run in UTC. Convert any human-readable schedule (e.g. "9am Eastern") to UTC before writing the cron expression. Daylight savings is not handled — pick a UTC time that's close enough year-round.

The lastRunAt pattern

interval.lastRunAt is the timestamp of the previous successful run (or undefined on the first run). Use it to fetch only items created since the last run, instead of re-scanning everything:

export default async function (interval: Interval) {
  const since = interval.lastRunAt ?? new Date(Date.now() - 24 * 60 * 60 * 1000);
  const newItems = await fetchItemsSince(since);
  for (const item of newItems) {
    await handle(item);
  }
}

This makes the val idempotent against missed runs and avoids reprocessing.

Reading and updating the schedule

  • read_interval_settings — fetch the current cron expression and active state of an interval file.
  • write_interval_settings — change the cron expression or pause/resume an interval.

When to skip a template

For simple scheduled jobs, create a new val with a single interval-type file directly — no template needed. Templates are for more complex shapes (dashboards, AI agents, webhook + UI combos).

Verifying changes

After editing an interval val, use run_file to invoke the handler manually instead of waiting for the next scheduled run.

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