Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), and the description adds what they cannot: result ordering (newest first), the shape of each item (name plus media URL), cursor-based paging, and the pre-upload visibility caveat. Minor gap: it never says the listing is brand-scoped/requires a brand context beyond the brandId param.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.