Weekly competitor page watch with screenshots to Slack

Every Monday at 8am, run a competitor page watch that spans Anchor Browser, Google Sheets, and Slack.

First, use Google Sheets Get Values to read the Watchlist tab of the configured spreadsheet. Each row is one competitor and gives you the competitor URL and a human label (for example, 'Acme — pricing page'). Also use Get Values on the Snapshots tab to load last week's captured page text for each row, keyed by the same URL, so the agent can diff against it later.

For each row in the Watchlist, call Anchor Browser's Web Unlocker with the URL to fetch the fully-rendered page text — this gets past bot protection and executes JavaScript, so single-page apps and gated marketing sites come through with their real content. Then call Screenshot Webpage on the same URL at a desktop viewport (roughly 1440x900) to grab a PNG. Screenshot Webpage is a one-shot AI tool that manages its own session, so no manual session lifecycle is needed. If either call errors or times out, record the row as skipped along with the error message and move on — do not fail the whole run.

Compare the new page text to last week's snapshot for the same URL and decide what actually changed. Focus on: new or removed products or plans, price changes, new headlines and taglines, new customer logos or social proof, changed calls-to-action, and any new feature copy. Explicitly ignore boilerplate churn: rotating banner content, timestamps, CSRF tokens, session ids, cookie notices, ad rotations, and any element that's clearly noise. If the site is new to the Watchlist (no prior snapshot exists), treat this run as the baseline for that competitor and note it as 'first capture — baseline set' rather than diffing.

Write a short markdown digest grouped by competitor. For each competitor with meaningful changes, use the human label as the heading and bullet the specific changes underneath in plain language. Skip competitors with no meaningful changes rather than listing them — the digest should be scannable. At the bottom, add a 'Skipped' section that lists any rows that errored, with the URL and the error reason, so the operator can fix broken URLs.

Post the digest to the configured Slack channel using Send a Message. Capture the message timestamp from the response and thread the screenshots under it: for every competitor with meaningful changes, use Upload a File to attach that competitor's PNG to the same thread, with a caption that names the competitor. Do not upload screenshots for skipped or unchanged competitors — the point is to keep the thread focused on what actually changed.

Finally, write the new page text back to the Snapshots tab using Batch Update Values so next week's run compares against this week's capture. For each successfully captured row, update the snapshot cell with the fresh page text and stamp the capture time as an ISO 8601 timestamp in the adjacent cell. Do not overwrite snapshots for rows that were skipped — leaving the old snapshot in place lets next week diff against the last known-good version once the URL is fixed.

Configuration expected from the operator: the Google Sheet id, the Watchlist and Snapshots tab names and their column layouts (URL, label, snapshot text, captured-at timestamp), the target Slack channel id, and the desktop viewport size for screenshots.