Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the disclosure burden and does well: it identifies the endpoint, says it is free, specifies 'no taker', describes the returned fields, and explicitly states that no transaction is returned. It omits error behavior, rate limits, and auth details, but covers the key behavioral traits for a read-only quote call.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.