Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnly, idempotent, and non-destructive behavior. The descripption adds useful behavior beyond annotations: it returns a download link when complete and does not expose the internal job identifier. It does not cover failure or polling behavior, but the safety profile is already covered by annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.