Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations the description carries the full burden and does so well: it discloses ordering (newest first), pagination contract (next_cursor passed back as cursor, null on last page), cost ('Free'), and error behavior (422 invalid_cursor, 422 for an invalid kind). This is unusually rich behavioral context for a list operation.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.