Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description must carry the behavioral disclosure burden. It does state the core behavior (scroll at a point by pixel deltas), but it does not clarify the coordinate system (viewport vs. page), scroll direction sign convention beyond pixel deltas, or what happens if coordinates are out of bounds. This is adequate but not rich.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.