Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare destructiveHint=true and idempotentHint=true, so the description doesn't need to restate those. However, it adds valuable context beyond annotations by specifying what is deleted ('previously stored memory') and the purpose ('clear sensitive data'), which helps the agent understand the nature of the operation.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.