Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already mark it read-only, idempotent, and non-destructive, and the description adds valuable behavior: the vote leaves the active tally but remains in public history, withdrawal is not erasure, the signing rule matches casting, and the returned message expires within 5 minutes. 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.