Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already mark it as read-only and idempotent. The description adds the authentication requirement and specifies the detailed return payload (timeline, metadata, cost, duration, alerts), which is valuable beyond the annotations. It does not contradict annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.