Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the burden. It adds context like 'FREE' and 'source-cited', implying a read-only lookup that returns a plain-language verdict with citations. However, it does not disclose exact return format, error behavior, or any side effects, leaving gaps.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.