Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover the safety profile (readOnlyHint, idempotent, non-destructive, openWorld), so the description's real contribution is disclosing the shape of the result set: three distinct derived metrics and the >50% threshold used for the Nakamoto coefficient. That matters because no output schema exists. It stops short of saying whether shares are percentages or fractions, or how pools with zero blocks are represented.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.