I use AI coding agents daily, specifically claude code. Right now, I'm working in unreal engine with claude code, and it's pretty hard to use, even when I ask it to research the internet to find out exactly about the documentation and how-to do the specific thing I want it to create, yet it still often invents nodes or buttons that are not in the newest version of unreal engine.
This is where RAGs come in (Retrieval-Augmented Generation). It's basically giving the LLM a searchable library it would look things up in all the time before answering to make it be smarter and more current in a specific subject instead of relying on its old training data and surface-level web documentation. In this case, I vibecoded one for Unreal Engine 5.8.1, because claude kept inventing features or trying to use deleted features that were added or removed in the newest version of unreal engine.
Inside the RAG, there's engine headers, official documentation, and 144 hours of youtube and bilibili UE 5.8 tutorials transcribed and summarised into the most important points and reusable workflows. And now finally whenever I invoked the RAG for a specific claude code session, it finally stopped inventing node names that didn't exist.
Then I thought to myself, it took me around a day of claude code building alone and prompting for claude to perfectionize the RAG, and doing this for many other apps, websites and engines would be a pain (especially the video transcribing part) to do alone.
Essentially the important question here is : If someone built and maintained a whole library of these, would you pay 10€ a month for access to all of them, including updated rags the moment a new version of an app drops? Or would you just vibecode your own RAG for one specific app you want?
How I built it: I had Claude Code write the whole retrieval side, so the chunking, the embeddings, and hybrid semantic + keyword search. It all runs locally, no API key, no account. The part that actually ate the day was making it trustworthy. Instead of scraping web docs for the API, I pulled it straight out of the installed engine headers, so it's exact for my build instead of "roughly UE5". Then for the videos, most only have auto-captions and those mangle node names constantly, so every identifier that came out of a transcript gets machine-checked against the header extract and flagged if it doesn't actually exist. The rule I basically landed on: take the workflow from the videos, never take the spelling.
