Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare idempotentHint=true, destructiveHint=false and readOnlyHint=false. The description adds genuinely new behavioral context: the action is user-visible ('Marked as resolved'), may trigger a push notification, and removes the conversation from the open inbox.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.