Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. Beyond that, the description adds two useful behavioral facts: access requires receipt credentials (an auth prerequisite not expressible in annotations), and returned data separates contact details from the request record — useful privacy context for interpreting the response.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.