OpenAI Cofounder Builds New Open Source LLM 'Nanochat' - and Doesn't Use Vibe Coding

An anonymous reader shared this report from Gizmodo:

It's been over a year since OpenAI cofounder Andrej Karpathy exited the company. In the time since he's been gone, he coined and popularized the term 'vibe coding' to describe the practice of farming out coding projects to AI tools. But earlier this week, when he released his own open source model called nanochat, he admitted that he wrote the whole thing by hand, vibes be damned.
Nanochat, according to Karpathy, is a 'minimal, from scratch, full-stack training/inference pipeline' that is designed to let anyone build a large language model with a ChatGPT-style chatbot interface in a matter of hours and for as little as $100. Karpathy said the project contains about 8,000 lines of 'quite clean code,' which he wrote by hand — not necessarily by choice, but because he found AI tools couldn't do what he needed.
'It's basically entirely hand-written (with tab autocomplete),' he wrote. 'I tried to use claude/codex agents a few times but they just didn't work well enough at all and net unhelpful.'

Read more of this story at Slashdot.