Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already mark this read-only, and the description adds meaningful behavioral details: it retrieves only publicly posted videos, and the page_token description discloses that pagination tokens are opaque, must be passed unchanged, and are scoped to the same user and sort type. It does not cover rate limits or error behavior, but those are secondary for a read-only list retrieval.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.