This is server-side change tracking for the web. You give it a query and a cadence (hourly, daily, weekly), and it runs persistent checks in the background, accumulating events when something shifts. It's the right tool when a user says "monitor this page" or "alert me when the price drops" instead of a one-off lookup. You can attach webhooks to get pushed notifications, or just poll for events later. The skill wraps parallel-cli's monitor command, which means you need version 0.3.0 or newer installed and authenticated. Honestly, it's just cleaner than writing your own polling loop, and the event history sticks around server-side until you delete the monitor.
npx skills add https://github.com/parallel-web/parallel-agent-skills --skill parallel-monitor