Watch any page and tell me when it changes
A quiet check of the pages you care about, with a diff only when something moved
Every [morning / few hours], open these pages: [URLs, e.g. a pricing page, a product's availability, a permit or case status, a job listing, a policy document, a leaderboard] and compare them to what you saw last time. Keep the last snapshot of the parts that matter [e.g. the price, the in-stock state, the status field, the list of items] in my sheet [link, or create one], and on each run append a row with the timestamp and current values. If nothing changed, do not message me. If something changed, tell me exactly what: old value, new value, and a link to the page, plus your read on what it means. If a page fails to load or its layout changed so you cannot find the field, tell me once rather than reporting a false change. Read-only: click nothing that submits, buys, or signs up.
