I have been building more and more web 3D with three.js: 2D, 3D and XR. Next to a game engine, there is almost no supply chain around it. Finding a 3D asset is easy. Finding one that is the right height, the right density and the right era, in the same visual language as the twelve other things already in your scene, is not. The reason is that a 3D model is sold as a finished object. Someone else already decided how tall it is. You can scale it, which stretches it and looks wrong, or you can open a modeling tool and fix it yourself, which is the part most web developers do not want to do. So I started building a library of 3D assets that are not objects but little programs: parametric, and customizable in the browser before you download anything. A traffic cone at two settings is not scaled, it is rebuilt, so a third reflective band appears once there is room for one. Assets are built in kits rather than one at a time, so the parts fit each other: one grid, one palette, one set of build rules per kit. And because a model is a program, you can import it like any other dependency, or hand it to an AI coding agent that can read its parameters, change one line and rebuild it. I am one person. The catalogue is built by a factory of agents, and my job is to supervise it. One agent writes each model as code and renders its own work through a harness that reports what was actually built, not what the agent believes it built. A different agent grades it in a fresh session, and that judge has sent back roughly two thirds of everything ever submitted to it. Then I look at every finished model myself. I have sent work back hundreds of times, usually about proportion, which is the thing a machine reviewer is worst at and a person spots instantly. It runs unattended, and none of it runs unsupervised. Polyfork is for people who build 3D for the web, for games and for XR without wanting to become modelers: three.js and React Three Fiber developers, Unity and Godot developers, and anyone whose AI coding agent needs a parts bin it can actually query. Where it is going: the largest set of 3D assets that arrive as code, installable from a URL, with a terrain generator for every kit and more knobs on every model. The first sale landed on launch day, 1 August 2026, and the catalogue has grown every week since.