Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden, and it does disclose one non-obvious behavioral trait: an approval step may gate the move. It still omits required permissions, what happens on approval failure, and whether the move is atomic, so the behavioral picture is incomplete but not empty.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.