Andrej Karpathy, an artificial intelligence researcher who co-founded OpenAI before getting poached by Tesla, announced on Tuesday that he’s joining Anthropic.

“I think the next few years at the frontier of LLMs will be especially formative,” Karpathy wrote in a post on X, referring to large language models. “I am very excited to join the team here and get back to R&D.”

Anthropic said Karpathy starts this week and will be building a team focused on using Claude to accelerate pretraining research, which helps the company’s models acquire their core knowledge and capabilities.

It’s the latest high-profile hire for Anthropic, which is poised to surpass OpenAI’s private market valuation and is in an intensifying battle for talent with its chief AI rival. Ross Nordeen, a founding member of xAI and an ex-Tesla employee, announced earlier this month he was joining Anthropic, the same day the company struck a deal with Elon Musk’s SpaceX to rent compute capacity at xAI’s Colossus 1 data center in Memphis, Tennessee.

After helping to start OpenAI, Karpathy left for Tesla in 2017 to serve as director of AI. There, he led the computer vision team for Tesla Autopilot.

Musk recruited Karpathy away from OpenAI while the Tesla CEO was a board member at both tech companies. Karpathy’s work at OpenAI and Tesla came up repeatedly during the Musk v. Altman trial, which concluded on Monday, with the jury and judge ruling in OpenAI CEO Sam Altman’s favor.

In one email exchange that was presented as an exhibit during the proceedings, Musk described Karpathy as “arguably the #2 guy in the world in computer vision,” behind Ilya Sutskever, another OpenAI co-founder.

“The OpenAI guys are gonna want to kill me, but it had to be done…,” Musk wrote, regarding his hiring of Karpathy.

Karpathy was one of several OpenAI employees Musk borrowed from OpenAI to do months of free work at Tesla, where the development of self-driving vehicles wasn’t going as quickly as promised. Karpathy left Tesla in 2022, and the company still doesn’t sell a vehicle that’s safe to use without a human driver ready to steer or brake at all times.

After leaving Tesla, Karpathy briefly went back to OpenAI before starting AI education startup Eureka Labs, where he has worked until now. Karpathy holds a PhD in computer science from Stanford.

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