Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already indicate the operation is not read-only ('readOnlyHint': false), not destructive, and idempotent. The description adds the contextual detail that the rule was disabled, which is helpful. It does not describe side effects or prerequisites, but for a simple activation tool the annotations carry enough of the behavioral burden.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.