Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare read-only, idempotent, open-world, and non-destructive behavior, so the bar is lower. The description adds useful context beyond annotations: 'verified', official statutory source (INPI / SIRENE), response size cap (<1.5 KB), and the specific official data elements returned.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.