Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=false, idempotentHint=false, destructiveHint=false, and openWorldHint=true. The description adds useful scope information ('all sessions'), clarifying that every active session is affected, but does not explain authentication requirements, whether the current session is included, or whether the action is reversible. With annotations covering the safety profile, this is adequate but not rich.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.