Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description adds significant context beyond the annotations: returns NHTSA safety recalls newest first, includes specific fields (component, summary, consequence, remedy, stop-driving/park-outside flags), and notes the model-level limitation. The annotations already cover read-only, idempotent, open-world traits; the description's value-add is the detailed return content and scope limits.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.