Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered and the description contributes nothing new about behavior. It does not say what a missing incident yields (404 vs empty), whether the response is the full incident object, or that describe_operation must be called to learn the request shape. No contradiction with annotations, but no added value either.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.