Anthropic can’t seem to stop winning. After a string of blockbuster model releases, a new funding round reportedly in talks at a valuation approaching $1 trillion, and an annual run rate that’s nearly parabolic; it’s now hired one of OpenAI’s—its bitter competitor—most famous alumni.
“Personal update: I’ve joined Anthropic,” Andrej Karpathy wrote onX on Tuesday, in a post that drew nearly 3 million views within one hour. He said the next few years at the frontier of LLMs would be “especially formative” and that he was eager to get back to research. He started this week on the pre-training team.
The decision suggests that Karpathy, whose writing on AI is followed by nearly two million people on X, has decided to put his stake in the AI race. He was first a founding member of OpenAI in 2015, left to run AI at Tesla, came back in 2023, and left only a year later to start his own education company, Eureka Labs.
Karpathy has been well known in AI for a decade, but the thing —or phrase — that etched him into AI legend was a tweet from last year. In February 2025, he posted that there was a “new kind of coding” that he called vibe coding: describe what you want plainly and let the model do the work.
