It's not very different from documentation, except it's not used for learning but rather immediate application, i.e. it's something you must include with each prompt/interaction (and likely need a way to determine which are the relevant bits to reduce token count, depending on the size of the main prompt.) In fact, this is probably one of the more important aspects of adapting LLMs for real-world use within real team/development settings that people don't do. If you provide clear and comprehensive descriptions of codebase patterns, pitfalls, practices, etc the latest models are good at adhering to them. It sounds difficult and open-ended, as this requires content beyond the scope of typical (or even sensible) internal documentation, but much of this content is captured in internal docs, discussions, tickets, PR comments, and git commit histories, and guess what's pretty great at extracting high-level insights from these types of inputs?