Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden, and it does disclose real behavioral traits: batch cap of 10 and the billing rule that invalid-format entries are not charged. But it says nothing about what the score means, error handling for valid-but-unknown CNPJs, output shape, or rate limits — significant gaps for a paid scoring endpoint.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.