Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden. It implies a read-only operation and hints that the result is snapped/simplified to axis directions, but it never states the return format, whether a normal is returned as a vector or enum, or what happens for non-axis-aligned or curved faces.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.