Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and idempotentHint=true, so the description doesn't need to restate safety. It adds useful behavioral context: the specific data sources (CERT Polska, UKE), the time-window behavior, and the open-data license (CC-BY). This goes beyond the annotations and helps set expectations without contradicting them.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.