Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description indicates it uses great-circle distance (Haversine formula) but does not disclose units or whether it's spherical vs ellipsoidal. Annotations are absent, so the description carries the burden, but the tool is straightforward with minimal behavioral nuance.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.