LLMs are built for scale so they've given up on the kind of online learning / "long term memory" processes that would individualize them.
The LLM is permanently locked to being a really cracked engineer on their first day at your company, looking at your codebase for the first time.
You can scaffold a bit with .md files, but at the moment they lack the ability to do what humans do: go to sleep, encode things from short to long term memory, and wake up the next day with more specific knowledge baked in.