Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover the safety profile (readOnlyHint=true, destructiveHint=false, idempotentHint=true). The description adds meaningful behavioral context by specifying the returned data elements, including the Ed25519 provenance status, which is not disclosed in annotations. There is no contradiction with annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.