Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare the read-only, idempotent, non-destructive, open-world profile, so safety is covered. The description adds meaningful behavioral context beyond that: it states that an empty feed is reported via limits[] and that the editorial look is provided, and explicitly says it does not invent products. This honesty guarantee is valuable and not captured by annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.