Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover the safety profile (readOnly, idempotent, non-destructive), yet the description adds substantial interpretive context: counts reflect administered findings only, the endogenous block measures the body's own peptide and is not evidence about taking it, and a 0 human count means none within the filters rather than no study existing. These caveats prevent real misreadings of the output. It stops short of describing ordering, pagination or response shape, but with an output schema present that is a minor gap.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.