Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the description does not need to repeat safety. It adds valuable behavioral context by listing exactly what is excluded (customer identifiers, internal ids, message bodies, etc.), which is crucial for privacy expectations and beyond what the schema or annotations provide.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.