Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare destructiveHint=true and idempotentHint=true, so the description doesn't need to repeat them. It adds no behavioral context beyond the annotations—no mention of irreversibility, failure behavior, or key-not-found handling. It only adds usage guidance, which belongs to a different dimension. 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.