Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the burden of explaining behavior. It clarifies whose identity is returned and implies a read-only operation, but it doesn't discuss response shape, error cases, or how identity is resolved. The auth precedence detail lives only in the schema, not the description.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.