Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden of behavioral disclosure. It only states the action 'close source monitor' without mentioning side effects, conditions (e.g., what happens if no source monitor is open), or any state changes beyond the obvious closure.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.