Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed world), so the bar is lower. The description adds real operational context beyond them: the dataset size (3,000 records), result ordering (rank-ordered), pagination, and explicit scope exclusions (no meanings, no availability checks).
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.