Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden of disclosing side effects; 'permanently' explicitly signals irreversibility and destructive behavior, which is the most important trait for a delete operation. It does not cover permission requirements or cascade effects on shares, but the core behavioral risk is stated.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.