Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and openWorldHint=true, so safety and open-world nature are covered without the description. The description adds only that results span three entity categories, and says nothing about result counts, pagination, ranking, or rate limits. With annotations carrying the safety profile, this is adequate but thin.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.