Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the transparency burden. It discloses the output (rates per 1,000 live births, breakdowns) and filter defaults (returns all states/years if not specified, case-insensitivity). It does not cover data source or missing-data behavior, but core call behavior is transparent.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.