Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already indicate non-read-only, non-idempotent behavior, so the description carries a lighter burden. It adds that the request is non-streaming and uses POST, but doesn't elaborate on side effects, authentication, or rate limits. No contradiction.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.