Mira Murati’s thinking machines loses co-founders as senior leaders return to OpenAI

Thinking Machines Lab, the artificial intelligence startup founded by former OpenAI CTO Mira Murati, has seen the exit of two of its co-founders, both of whom are returning to OpenAI, along with another senior researcher.

Murati confirmed on social media that the company had parted ways with co-founder and chief technology officer Barret Zoph. She announced that Soumith Chintala would take over as CTO, describing him as a seasoned AI leader with more than a decade of contributions to the field and a key member of the Thinking Machines team. Murati did not publicly reference the departure of other co-founders.

Shortly after Murati’s post, OpenAI’s CEO of applications, Fidji Simo, announced that Zoph, co-founder Luke Metz, and researcher Sam Schoenholz would be rejoining OpenAI. Simo said the move had been in progress for several weeks and expressed enthusiasm about their return.

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Metz and Schoenholz had both previously worked at OpenAI before joining Thinking Machines. Zoph had served as OpenAI’s vice president of research prior to co-founding the startup and earlier spent six years at Google as a research scientist. Murati herself left OpenAI in September 2024 to launch Thinking Machines alongside Zoph and Metz, taking on the role of CEO.

The startup has drawn significant attention and funding since its launch, closing a $2 billion seed round in July led by Andreessen Horowitz, with participation from Accel, Nvidia, AMD, and Jane Street. The round valued Thinking Machines at $12 billion.

Reports suggest the separation between Zoph and the startup may not have been smooth. Wired reported that the split was not amicable, and Murati’s brief public remarks offered little detail on the circumstances surrounding the departure.

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While talent movement between major AI companies is common, the loss of multiple co-founders within a year of formation is notable. The departure is particularly significant given Zoph’s role as CTO and the startup’s efforts to build credibility through a team of prominent researchers from OpenAI, Meta, and Mistral AI.

Thinking Machines has also seen other senior exits, including co-founder Andrew Tulloch, who left in October to join Meta. At the same time, OpenAI has experienced its own wave of departures in recent years, with several former co-founders leaving to launch or join rival AI ventures before some returned.