Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=false, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds nothing on top: it does not say whether the unread count is decremented, whether marking an already-read notification errors or no-ops, or how failures surface — all useful context for a state-mutating call.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.