Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description must disclose behavioral traits, but it only states the action without any side effects. It doesn't mention whether it requires an active sequence, whether it toggles playback, or what happens if no timeline is open. The phrase 'expanded operation' adds no concrete behavior.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.