Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The annotations already declare destructiveHint=true and idempotentHint=true, so the description doesn't need to restate destructiveness. It adds context about clearing sensitive data and implies the memory must have been stored previously. However, it doesn't clarify edge cases like what happens if the key doesn't exist or whether the deletion is permanent beyond the annotation.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.