Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already provide readOnlyHint=true and destructiveHint=false, so the description does not need to restate those. The description adds details about the returned fields (invoiced, paid, etc.) but does not disclose any additional behavioral traits such as data freshness, permissions, or latency. With annotations covering the safety profile, a score of 3 is appropriate.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.