Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already indicate destructive behavior. The description adds minimal context beyond confirming the action. It doesn't describe side effects (e.g., reverting to default banner) or permission requirements. With destructiveHint present, description's burden is lower, but still lacks depth.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.