Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare destructiveHint=true, readOnlyHint=false, and idempotentHint=true, so the description's 'Delete' is consistent. It adds the 'clear sensitive data' context and pairing note, but does not disclose additional behavioral details such as behavior for nonexistent keys or side effects. This provides some value beyond annotations, warranting a 3.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.