Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full behavioral burden and discloses almost nothing: it does not say whether the call is read-only, how the uploaded-video list is bounded or paginated, or what happens for an unknown agent_name. 'Get' weakly implies a read, but that is inference rather than disclosure.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.