Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover the read-only, non-destructive safety profile, yet the description adds real value: deterministic behavior, sanitized JSON output, 'safety receipts', and a 0.01 USDC payment on Base. The payment/cost requirement is behavioral context an agent cannot get from annotations. It does not explain how payment is settled, which holds it back slightly.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.