Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden of behavioral disclosure. It accurately describes the calculation and adds a useful interpretation threshold. However, it does not mention data source, freshness, or any limitations (e.g., if it returns null for unknown suburbs). For a simple metric tool, this is acceptable but 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.