Thinking Machines cofounders Barret Zoph and Luke Metz are leaving the fledgling AI lab and rejoining OpenAI, the ChatGPT-maker announced on Wednesday. OpenAI’s CEO of applications, Fidji Simo, shared the news in a memo to staff this afternoon.
Two narratives are already forming about what prompted the departures. The news was first reported on X by technology reporter Kylie Robison, who wrote that Zoph was fired for “unethical conduct.”
A source close to Thinking Machines alleged that Zoph had shared confidential company information with competitors. WIRED was unable to verify this information with Zoph, who did not immediately respond to WIRED’s request for comment.
According to the memo from Simo, Zoph told Thinking Machines CEO Mira Murati on Monday he was considering leaving. He was then fired on Wednesday. Simo went on to write that OpenAI doesn’t share the same concerns about Zoph as Murati.
The personnel shake-up is a major win for OpenAI, which recently lost its VP of research, Jerry Tworek. A third Thinking Machines staffer, Sam Schoenholz, is also rejoining OpenAI, per the company’s announcement.
The departures are a blow to Thinking Machines, which also lost another co-founder, Andrew Tulloch, in November when he took a new job at Meta. In a post on X, Murati confirmed Zoph’s depature and said that Soumith Chintala will replace him as the startup’s chief technology officer.
Zoph and Metz left OpenAI in late 2024 to start Thinking Machines with Murati, the ChatGPT maker’s former chief technology officer. Zoph was previously OpenAI’s vice president of post-training, where he led teams that made final improvements to AI models before they were deployed into products like ChatGPT and OpenAI’s API. Metz worked at OpenAI for two years during his first stint at the company and contributed to projects like ChatGPT and the o1 AI reasoning model.
Simo told employees in her memo that Zoph will report directly to her, and Metz and Schoenholz will work under him. The hiring announcement timeline was accelerated, she said, so they still have to work out some details about their roles.
Thinking Machines Lab is one of several well-funded AI startups led by former top OpenAI researchers, reflecting the incredible appetite among investors to cash in on the AI race. Last year, Murati’s startup was last valued at $12 billion, and was recently in talks to raise more than $4 billion at a $50 billion valuation. The startup’s main product today is called Tinker, which allows developers to customize AI models on their own datasets.