Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and idempotentHint=true, so the safety profile is covered. The description adds useful behavioral details: it returns percentages, supports stopword filtering, and honors a top N limit. It does not go into edge cases like punctuation handling or case sensitivity, but the added context is meaningful beyond the annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.