Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full burden, and it discloses almost nothing: not whether validation is a read-only check, whether it requires the model to be loaded/installed, what constitutes a pass/fail, or whether it can fail. An output schema exists, so return-value detail is partly excused, but the behavioral gaps are substantial.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.