Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Without annotations, description carries full burden. It states it returns exact_probability, cumulative_probability, and std_deviation, adding some value. However, it does not mention constraints like k must be ≤ n or error scenarios, which the schema partially covers.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.