Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the behavioral burden. It clearly communicates the mutative outcome (a new stereo track is created), but does not disclose whether the new track becomes selected, how it is positioned, or whether it is undoable. This is adequate but not rich for a creation tool.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.