Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover the safety profile (readOnlyHint, idempotentHint, openWorldHint=false), so the description's job is to add context, and it does by disclosing the returned fields: reason, expected effect, and targeted engine. It omits freshness/recency, result limits, and whether an empty list means 'no recommendations' or 'not yet analyzed'.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.