Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare destructiveHint=false and idempotentHint=true, and the description adds genuinely useful context beyond them: the case, docket history, Case Passport and CaseMail address all persist and only monitoring stops. That concretely answers "what does this destroy?" (nothing), though it says nothing about permissions, error behavior, or idempotency in prose.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.