Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover read-only, idempotent, and non-destructive behavior, so the description does not need to restate those. It adds useful context beyond the annotations: availability is tied to the latest catalog sync, so results may not be real-time. It also clarifies the scope includes variants/options.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.