Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already indicate the operation is not read-only and not destructive, and the description adds the useful behavioral detail that the result is a digest that is also saved to the in-app inbox. It does not discuss duration, errors, or required permissions, but for this simple action the disclosed behavior is adequate.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.