Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare the tool as read-only, idempotent, and non-destructive; the description adds value by revealing that it combines benchmark and static estimates and includes an authentication requirement. This goes beyond the annotation safety profile without contradicting it.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.