LLM's are language models, you can absolutely control them with bash scripts and deterministic code, there are plenty of frameworks that already do that, and a great engineer will use them, but LLMS are at their most powerful when a user can give the agent an input and the model can run its ReAct loop. Wanting to free an LLM from a chat pane is like wanting to free email from the thread model, or closer, removing the chat window to DM a friend or colleague.
>what can we learn from the before-fore times, when people used to actually write code?
Treat an agent like a human writing code. Give them the best context, give them the best tools. This is why harnesses are overly complicated, because they need to guide the model through the context and tools it has available in a way that is efficient. A good harness is not incompatible with the Unix philosphy, it can do one thing well (interfacing with LLMs and giving them access to filesystems and compute), it will heavily use bash, stringing commands together with the cli tools that it knows (it's context) that it has, and and LLM will naturally handle text streams because that is what it does best.
>Everything is a File
If you want things to be deterministic why resort to plaintext? Wouldn't we want as much as possible to be typed? A computer can parse json which is what you want if you are trying to make your harness as deterministic as possible.
>It watches our FS for changes with cursors on textfiles,
Wow. What is your monthly token bill? I don't know how that would use less tokens than a 30 minute heartbeat, which as you mention will already use a lot of tokens. Why not have it notify your agent after a certain amount of files have been changed, or certain files you deem important?
It seems like this user works at a 12 week programmer retreat and seems to post their cohort's blog posts about the projects they work on.