Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare read-only, idempotent, non-destructive, and open-world behavior. The description adds useful context beyond annotations by explaining that results are top values with counts and that the aggregation can be scoped by a full-text query. No contradiction with annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.