Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnly/idempotent/non-destructive, so the bar is lower; the description still adds real context: paginated return shape, that each strategy carries 7d avg APY for its default range, and the decimal-fraction convention (1.0 = 100%). It omits anything about rate limits or response size ceilings, keeping it short of 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.