Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden. It conveys the destructive cascade (all exercises are removed with the block) but says nothing about permissions, reversibility, whether the session must exist, or what happens to an emptied session.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.