Thinking Machines Lab, a startup founded by former OpenAI head Mira Murati, has announced the departure of two of its co-founders. Both co-founders are rejoining OpenAI. In addition, another former OpenAI employee who worked at Murati's startup is also returning to the company.
Mira Murati shared on social media that the company's co-founder and CTO, Barret Zoph, has left. Soumith Chintala has been appointed as the new CTO. Murati described Chintala as a professional leader with many years of experience in the field of artificial intelligence.
Murati did not mention other departures in his statement, but shortly after, OpenAI's Chief Applications Officer Fidji Simo confirmed that Barret Zoph, as well as other Thinking Machines co-founders Luke Metz and Sam Schoenholz, had returned to OpenAI.
Barret Zoph previously worked as a vice president of research at OpenAI and previously as a researcher at Google. Mira Murati was OpenAI's CTO until September 2024, and later founded Thinking Machines Lab. The startup was valued at $12 billion in July 2025, having raised $2 billion in initial investment.
Experts say that the departure of two co-founders less than a year after the startup's founding could be a serious loss for the company.
