Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Adds substantial behavior beyond the annotations: the change becomes permanently unconfirmable, only the preparer may cancel it, and calling it on an already-confirmed change reports that fact rather than undoing it. The annotations cover the safety profile (destructiveHint=false, idempotentHint=true) and the description adds authorization and state-transition semantics without contradicting them.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.