Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already establish readOnlyHint, idempotentHint, and destructiveHint; the description goes beyond them by adding caller scoping, status filtering, ordering, and a tier constraint ('sp500+ (sample rejected)'). This is useful behavioral context not present in the annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.