Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full burden. It discloses that page content is not stored, which is useful behavioral context, and implies the tool performs an HTTP fetch to determine status. However, it does not mention rate limits, caching, whether the URL is fetched or merely parsed, or what happens on redirects or failures.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.