Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description must carry the behavioral burden. It conveys a read-only intent, the trending-by-engagement ordering idea, and a limit of 20, but it does not explain page/cursor interplay, direction of engagement ordering, or default behavior. This is minimal but not wholly uninformative.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.