Comment by empath75

If your product has code on it that can only be understood and worked on by the person that wrote it, then your code is too complex and underdocumented and/or doesn't have enough test coverage.

Your time would be better spent, in a permanent code base, trying to get that LLM to understand something than it would be trying to understand the thing yourself. It might be the case that you need to understand the thing more thoroughly yourself so you can explain it to the LLM, and it might be the case that you need to write some code so that you can understand it and explain it, but eventually the LLM needs to get it based on the code comments and examples and tests.