Murati’s Thinking Machines Lab Hit as Co-Founders Return to OpenAI

Mira Murati’s AI startup, Thinking Machines Lab, is losing two co-founders as key leaders head back to OpenAI, marking a major shake-up less than a year after the company was formed. Murati, a former OpenAI chief technology officer, confirmed on Wednesday that co-founder and chief technology officer Barret Zoph is leaving the company. She said the startup has “parted ways” with Zoph and announced that Soumith Chintala will take over as the new CTO. Murati described Chintala as an experienced leader with more than a decade of work in the field and said he has already been an important contributor to the team.

Murati’s message did not mention any other exits. However, less than an hour later, OpenAI’s head of applications, Fidji Simo, posted that Zoph would be returning to OpenAI along with two others tied to Thinking Machines: co-founder Luke Metz and Sam Schoenholz, another former OpenAI employee whose online profile still listed him as working at Murati’s startup. Simo said the returns had been planned for several weeks and that OpenAI was excited to bring them back.

Zoph previously served as OpenAI’s vice president of research and earlier worked at Google for six years as a research scientist. Murati left OpenAI in September 2024 and later co-founded Thinking Machines with Zoph and Metz, taking the CEO role. The startup quickly attracted major backing, including a reported $2 billion seed round in July led by Andreessen Horowitz, with investors such as Accel, Nvidia, AMD, and Jane Street also participating. That funding round valued the company at $12 billion.

TechCrunch said it has contacted both companies for comment. Wired reported that the split between Zoph and Thinking Machines was not friendly, and Murati’s brief public statement added to the questions around the departure.

Talent moves between top AI labs are common, but the loss of two co-founders so soon is notable, especially with the departure of a CTO. The startup has also seen other senior exits, including co-founder Andrew Tulloch, who left for Meta in October. The changes raise fresh pressure on Thinking Machines as it tries to build momentum with a high-profile team drawn from OpenAI and other leading AI groups.