Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already carry the safety profile (readOnly, idempotent, non-destructive), so the description isn't burdened with that. It adds genuinely useful behavior beyond the annotations: the two-key sort order and how sort_by modifies the second key, the interpretation caveat about ranking, and the free-tier limit of 25. Minor gaps on pagination/return shape remain.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.