Three.js is not CAD. It is an API for drawing 3D graphics in a browser. 3D graphics, in general, is not CAD. Blender is not CAD. You cannot do CAD operations in blender.

I'm not being nit picky here. I think there are issues beyond terminology that you may not be familiar with, as it is clearly not your field. That's ok.

The "design" in computer aided design is engineering design. This is not the same definition of "design" used in, say, graphic design. Something is not called CAD because it helps you create an image that looks like a product on a computer. It is CAD because it creates engineering design files (blueprints) that can be used for the physical manufacture of a device. This places very tight and important constraints on the methods used, and capabilities supported.

Blender is a sculpting program. Its job is to create geometry that can be fed into a rendering program to make pretty pictures. Parasolid is a CAD geometry kernel at the core of many CAD programs, which has the job of producing manufacturable blueprints. The operations supported map to physical manufacturing steps - milling, lathe, and drill operations. The modeling steps use constraints in order to make sure, e.g., that screw holes line up. Blender doesn't support any of that.

To an engineer, saying that an LLM gave you a blender script for a CAD operation is causing all sorts of alarm klaxons to go off.