Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description adds the useful nuance that these are stored, public records (not live data), but says nothing about miss/error behavior or pagination. With annotations carrying the safety profile, this is a solid-but-not-rich 3.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.