Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is covered. The description adds valuable context beyond that: it specifies a cost of $0.5 USDC and that the return is an object with 7 fields including attestation and disclaimer.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.