Check a site now: fetch its home page and up to five key page URLs, look for the loader with this site's key, store the result and apply the health rule. Any page carrying the key verifies the site; a key page without it is flagged in last_check_result.pages. A loader installed through a tag manager is not in the page source: such a site is verified by its first hit instead, so loader_missing on a receiving site is not a fault. A disabled site is 409 invalid_transition. Up to a minute.

Contract:

• MCP tool verify_website_site, registry package mcp.signals/website_sites, mount signals.website.
• Operation action, response envelope action.
• Flags: none.