Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description must disclose behavioral traits, but it only restates the tool's name. It does not mention that the search is read-only, whether it returns matches or a single result, pagination, or matching behavior beyond what the schema's 'partial match' note provides (which is in the schema, not the description).
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.