Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnly, idempotent, non-destructive, and open-world behavior, so the safety profile is covered. The description adds the operational shape of the tool (single call, fixed field set, Base-only scope), which is genuinely useful beyond the annotations, though it says nothing about rate limits, caching, or freshness of the data.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.