Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already indicate read-only, idempotent, non-destructive behavior, and the description adds the operational guarantee that no second Vibes-Coded payment challenge is generated. This is useful context beyond the annotations, though the phrase is somewhat jargon-heavy and does not describe potential network or external-service behavior.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.