Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover safety (readOnly, idempotent, non-destructive). The description adds the detail that the search is 'in the guide,' implying data source and freshness context, but does not disclose other behavioral traits like rate limits, result pagination, or how no-results are handled.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.