Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden, and it does disclose the core behavior: a random whole number with inclusive bounds and default values. It does not mention side effects, error handling, or randomness guarantees, but for a simple stateless number picker this is adequate though not rich.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.