Andrej Karpathy has joined Anthropic and began work on the company's pre-training team led by Nick Joseph. He will start a team focused on using Claude to accelerate pre-training research, a spokesperson said.

Karpathy announced the move in a post online. "Personal update: I've joined Anthropic. 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 wrote.

Pre-training is responsible for the large-scale training runs that give Claude its core knowledge and capabilities, according to the company. It is one of the most expensive, compute-intensive phases of building a frontier model.

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

Alongside his industry work, Karpathy has taught an online course called Neural Networks: Zero to Hero that helps students learn to build neural networks from scratch in code. He also maintains a YouTube channel where he semi-regularly posts lectures on large language models and AI.

In his post announcing the move to Anthropic, he indicated he intends to return to education-focused work. "I remain deeply passionate about education and plan to resume my work on it in time," he wrote.