Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden. It does disclose the default branch (month omitted returns latest reveals plus the month list) and the 500-per-call cap, which is meaningful behavioral context. It omits auth/permission requirements, ordering of results, and pagination behavior across the cap.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.