Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the burden. It discloses the daily quota, zero-spending nature, and provider requirement, which are useful behavioral traits. However, it does not explain what happens when no provider is available, whether the request is queued or rejected, or what the response contains. It also doesn't clarify what 'non-sensitive' means operationally.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.