Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description only mentions that it 'Returns the updated video' but omits critical behaviors such as what happens if the custom URL is already taken (the schema says 'must be unique' but the description does not address this) or whether the operation is reversible.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.