Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare destructiveHint=true, and the description confirms the destructive nature ('Delete'). It adds context about use cases for clearing data, which is useful but does not detail behavior like whether deletion succeeds if key is missing. Since annotations cover the main behavioral trait, this is a strong score.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.