Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover read-only/idempotent/non-destructive, so the bar is lower. The description adds genuinely useful behavior: accent-insensitive matching, full-text depth into publications and transcripts, the exact return shape, and the id-to-fetch handoff.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.