Best AI auto completion and search using project aware RAG for non-code writing, like articles, design documents, educational content etc

When I write code I use codeium for auto completion and searching the code base. I don’t know if it’s the best one but the great thing is that it uses all the code I’ve already written (in this file and others in the project) as context (using RAG).

Because of this it usually “understands” what I’m referring to (a class and its methods in a different file, or similar kinds of code I’ve written elsewhere) and how that can be used for my current needs, allowing me to auto complete a lot of code that it can guess from what I’ve already begun writing. It’s also very good at using my style of coding because of this.

For unfamiliar code bases it allows me to search and examine, ask questions about the whole project, and it can figure it out from the context of various related files after having indexed their contents.

I would like similar functionality for my non-code writing. For instance, when I have a bunch of notes I’ve written over time on some topic, as well as snippets and references texts, I now want to write a cohesive text about it. It could be a game design document, a tutorial how to better your personal finances, or a more formal educational text on algorithms used with TCP to deal with congestion.

I want to be able to search through and ask questions about the collected materials like “what was it exactly some author said about x”, as well as have it used as context for auto completion when I’m writing. It absolutely must be able to suggest text to include (or edit) as part of the text editor while I’m writing – not as a separate chat – as it’s simply not productive enough otherwise. Does anyone know about a good tool for this?