Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries full burden. It discloses that data comes from EdFacts, includes cohort counts and midpoint rates, and notes that graduation data may lag. It also mentions state is required and county is optional. However, it doesn't describe response structure or pagination, though an output schema exists.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.