Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the description doesn't need to repeat those. It adds valuable context beyond annotations: authentication requirements (X-Vibes-Key or x402), cost (~$0.02), advisory-only nature, and the return format (JSON with drifted fields and severity, or payment_required). No contradictions with annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.