Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description adds context beyond annotations, such as the memory being 'previously stored' (implying the key exists) and the use case for clearing sensitive data. Annotations already indicate destructive and idempotent behavior, but the description enriches understanding without contradiction.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.