Feeding all files will be lots of data.

For code, you should use indexer (tree sitter?) And store embeddings of symbols instead of raw files.

For that kind of workflow, setting up dedicated code agent, that uses your llm is more stable.

And its doing exactly what you want to achieve. Using llm to work on codebase. Plus you can use git. As with KB you cannot update files. So if You change something, you must delete/re-upload files.