Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare idempotentHint=true, destructiveHint=false, and readOnlyHint=false, so the mutation safety profile is covered. The description adds the useful scope distinction that all=true affects every notification, which is context beyond the annotations, but it says nothing about permissions, reversibility, or interaction when both ids and all are supplied.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.