Hello! Houdini 18.5 listed “OSL shader authoring in VOPs” as a new feature. I couldn't manage to find any help in the document.
Where do I find those vops and how to get started. Thanks for your help.

Now, there is a shader translator for OSL Shader Builder, which correctly translates it to a USD shader prim. It's mainly for RenderMan, but if you configure the compiler parameter, then it should work for other renderers too.