Andrej Karpathy, the AI researcher who co-founded and formerly worked at OpenAI and previously led AI at Tesla, has joined Anthropic.

“I’ve joined Anthropic,” Karpathy posted on X Tuesday. “I think the next few years at the frontier of LLMs will be especially formative. I am very excited to join the team here and get back to R&D.”

Karpathy started this week at Anthropic, where he is working on pre-training under team lead Nick Joseph. Pre-training is responsible for the large-scale training runs that give Claude its core knowledge and capabilities, according to the company. It’s also one of the most expensive, compute-intensive phases of building a frontier model.

An Anthropic spokesperson told TechCrunch that Karpathy will start a team focused on using Claude to accelerate pre-training research.

Karpathy is one of the few researchers who can bridge the gap between LLM theory and large-scale training practice. Tapping him to build such a team is a clear sign from Anthropic that it believes AI-assisted research, rather than pure compute, is how it stays competitive with OpenAI and Google.

While at OpenAI, Karpathy focused on deep learning and computer vision until he departed in 2017 to join Tesla. He led Tesla’s Full Self-Driving (FSD) and Autopilot programs before leaving in 2022.
He then went back to OpenAI for one year before leaving again in 2024 to start Eureka Labs, a startup dedicated to applying AI assistants to education.

Karpathy hasn’t shared many updates on Eureka Labs since its launch, and it’s not clear if the renowned researcher will continue with the startup. He has also taught an online course called Neural Networks: Zero to Hero that helps students learn to build neural networks from scratch in code, and has a YouTube channel where he semi-regularly posts lectures on LLMs and AI. 

“I remain deeply passionate about education and plan to resume my work on it in time,” Karpathy said.

TechCrunch has reached out to Karpathy for comment.

Separately, Anthropic has also brought on Chris Rohlf to its frontier red team, which stress-tests advanced AI models against severe threats. Rohlf is a veteran of the cybersecurity industry with more than 20 years of experience. He previously worked at Yahoo’s well-respected cybersecurity team known as “The Paranoids,” and more recently at Meta, where he worked for six years before joining Anthropic. Rohlf was also a fellow at Georgetown’s Center for Security and Emerging Technology, where he worked on the CyberAI project.

“We have a real opportunity in front of us to dramatically improve cyber security with AI,” Rohlf said in a post on X. “I can’t think of a better company or team to join at this critical moment in time.”