They say they use LangChain, so it's going to be structurally similar to this MVP side-project: https://thundergolfer.com/infinite-ama.

That's a chat-bot backed by LangChain and OpenAI, which can answer some questions from my knowledge base.

It's WIP, I want to add my HN comments into the mix, but the code is here: https://github.com/thundergolfer/modal-fun/tree/main/infinit...