Additionally, the more information you put into the context the more confused the LLM will get, if you did dump the whole codebase into the context it would not

Additionally, the more information you put into the context the more confused the LLM will get, if you did dump the whole codebase into the context it would not suddenly understand the whole thing. It is still an LLM, all you have done is polluted the context with a million lines of unrelated code, and some lines of related code, which it will struggle to find in the noise (in my experience of much smaller experiments)