Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already indicate read-only, idempotent, non-destructive behavior, so the description's job is lighter. The description adds useful transparency by disclosing exactly what payload is returned (config bundle with specific fields) and that it is a single preset with a version selection, which helps set expectations. No contradictions with annotations appear.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.