Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, openWorldHint, idempotentHint, destructiveHint. The description adds value by explaining that categories are returned with counts and are filterable facets (e.g., 'Best for Kids', 'Sports'). This provides context beyond annotations, though behavioral traits are well-covered.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.