Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Adds meaningful context beyond annotations: returns confirmation and estimated response time, urgent messages are prioritized, and authentication is required. This complements the annotation hints, though it does not explain the unusual destructiveHint=true, but no contradiction exists.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.