Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full behavioral burden. It usefully discloses the return shape (the six field attributes) and the keying contract for downstream submission, which is genuinely helpful. It says nothing about mutability, permissions, or whether the field set is static, though for a simple field-listing read there is little risk to disclose.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.