Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description adds real behavioral context beyond that: it discloses the decoded Transfer-event output and, unusually, the exact cost ($0.003 USDC via x402), which matters for an agent deciding whether to invoke a paid endpoint. It stops short of noting auth/payment flow details or behavior on an unknown hash.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.