I've been thinking about a new AI based dimension to this. If your program is split into smaller decoupled "modules" then all the code for each "module" can fit into an AI context window. In this way the AI can have all the context to edit a "module" by just loading all the code for that "module". You would not need things like vector search as much. If we assume 20 tokens per line of code and the AI context window is 100k to 1M tokens, then that would argue for having "modules" between 5,000 and 50,000 loc, depending on which AI model you are using.

> then that would argue for having "modules" between 5,000 and 50,000 loc, depending on which AI model you are using.

FWIW, I set hard limits to 200 LOC for every single source code file in any AI-related projects, also with restrictions on "formatting hacks" and other golf-like stuff.

I think beyond 5000 LOC in a single file and all available models already get lost frequently, even if the "context limit" theoretically is way above that. Maybe aim for like 1K LOC at max unless you want to have lots of misunderstandings.