Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already mark the operation read-only, idempotent, and non-destructive, so the description adds relevant context over and above that: bounded pagination and the explicit exclusion of records, appointments, patient data, and clinical content. This gives a safety/privacy boundary beyond the annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.