Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover readOnly, idempotent and non-destructive, so the safety profile is handled. The description adds non-obvious context beyond them: the content is full text, it is licensed by the issuing body, and citations must include the source URL. It still omits return shape/pagination, hence not a 5.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.