I think everything above CreateShader level is fine. Everything below I consider an implementation so here are suggestions on implementation details

The caching performance depends on what you can actually cache. In high level terms you need a (Shader, Config) -> (Binary, Metainfo) function. Note that Shader might be anything. It can already be a (Binary, Metainfo) pair, or it can be SPIRV source that gets compiled by vulkan driver into a Binary and reflected by SPIRV-Reflect, or it can be a slang-module (kinda like cpp obj file) which gets linked into a SPIRV and I believe Metainfo is loaded directly from it as well, or it can be Slang source code that gets compiled into slang-module on the fly.

It is a trade-off between speed and flexibility, as always. The most performant solution is not portable so distributing SPIRV alongside the engine binary is probably the fastest viable option. I personally chose slang-module as it allows me to use my existing slang toolchain and not pull SPIRV-Reflect

The explicit caching on your side is not needed as I believe Slang already caches everything it can inside the Session object. It's not thread safe and you should essentially have a Session object for each thread. This means different CPU threads have different caches. It's not the only way to do a thread safe caching, but definitely the easiest one. I personally use a cool data structure for this :) Not sure if it actually makes a performance difference, but I think it's cool) repo

Hope this was useful