Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations mark readOnlyHint=false, which already flags mutation. The description adds meaningful behavioral context: it removes only the caller's membership and enforces a last-owner constraint. It does not fully discuss reversibility, but for a simple leave operation with output schema present, this is solid.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.