Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare destructiveHint=true and readOnlyHint=false, so the description's 'Delete' statement adds little beyond the structured data. It does add the nuance of 'clear sensitive data' and the pairing reminder, but no additional behavioral traits (e.g., what happens if the key doesn't exist) are disclosed. Since annotations carry the safety profile, this modest addition warrants 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.