Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The annotations already declare readOnly, idempotent, and non-destructive behavior. The description adds useful context beyond annotations by describing the canonical, fixed nature of the list (26 systems) and enumerating the fields returned, making the stable read-only behavior concrete.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.