Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Discloses that the tool does not move funds and that the returned payment_required_b64 should be passed unchanged to an x402-compatible wallet/client. Clarifies that the live amount, asset, network, destination, and quoteId are authoritative, adding valuable behavior beyond annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.