OpenAI cofounder Andrej Karpathy joins Anthropic

Andrej Karpathy, one of OpenAI’s original co-founders and a prominent AI researcher, has joined Anthropic, where he will work on pre-training research and help develop efforts to use Claude to accelerate model training.

Karpathy announced the move on X, saying he was returning to hands-on research and development.

He noted that the coming years in large language model development are likely to be especially important, and said he was excited to re-engage with frontier AI work.

Anthropic confirmed that he started this week and will report to Nick Joseph, contributing to pre-training efforts, the stage where large language models learn general patterns and capabilities from large-scale data before later fine-tuning.

Pre-training is widely considered one of the most resource-intensive and strategically important parts of building foundation models. Improvements in this stage can have outsized effects on model performance, efficiency, and capability scaling. Anthropic said Karpathy will also help build a team focused on using Claude to speed up pre-training research and experimentation.

Karpathy was an early OpenAI researcher before joining Tesla in 2017 as head of AI for Autopilot computer vision. He left Tesla in 2022, briefly returned to OpenAI, and later founded AI education startup Eureka Labs.