Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover read-only and idempotent behavior, so the description does not need to repeat those. However, the description adds little beyond that—no detail about what is included in the list or constraints like pagination behavior, which could be useful context.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.