Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover readOnly=false, destructive=false, and idempotent=true. The description adds valuable context beyond these: it requires authentication, returns the resulting unread count, and explicitly emphasizes that unselected notifications are preserved. This enhances the agent's understanding of side effects and preconditions without contradicting annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.