A few things kind of aligned over the last month. I d been wanting to try pi.dev (https://pi.dev), DeepSeek has a very aggressive 75% discount on their v4-pro model until end of May, and I had this old itch from my LFS days to do my own thing with POSIX utilities.So I set up to do an experimental project with strict architectural rules, pointed an LLM at it, and fed it the BusyBox test suite as ground truth.The result: 77 POSIX utilities in pure Go, single static binary (~10MB), and it passes 548 of 552 BusyBox tests.My Honest take: this project is ~90% wiring the AI to do the heavy lifting, ~10% steering it in the right direction. Took about 3 weeks of prompts and plans and all that. Harness engineering works when you have a solid test suite to validate against, I know, it is an obvious statement, but I have hard evidence now to prove it.The test suite is the actual hero here, I cannot stress this enough. Without BusyBox s brutally thorough test suite, this project is just random hallucinated code.Also, I m not trying to replace BusyBox. It s an experiment. I m happy with how it went, cheers! Repo: github.com/ramayac/goposix (https://github.com/ramayac/goposix)