Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover the full safety profile (readOnly, idempotent, non-destructive, closed-world), so the description only needed to add context. It adds nothing about ordering, pagination, or what an 'episode' actually is, leaving the semantics of the returned data unexplained.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.