Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already mark this as read-only/idempotent, and the description adds value beyond that: unmined blocks return found:false with a reason rather than an error, results are raw chain data with no interpretation, and access details (x402 pricing, x-credit-token header, free tier, no key/wallet) are disclosed. No contradiction 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.