Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, so the safety profile is covered. With no output schema, the description is the sole source of return information and it fully discloses the payload (version, connection state, full tool list with one-line descriptions), which is meaningful added context. It doesn't mention pagination or payload size for the all-tools listing, but for a zero-side-effect tool the coverage is solid.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.