Thinking Machines Lab, an ambitious artificial intelligence startup led by former OpenAI chief technology officer Mira Murati, is facing a serious staffing crisis. Two of the company's three co-founders, Barret Zoph and Luke Metz, are leaving the company and returning to OpenAI. They are joined by another former OpenAI employee, Sam Schoenholz.
Return to OpenAI
On Wednesday, January 14, 2026, Mira Murati announced on the social network X the departure of Barret Zoph, who served as the company's chief technology officer (CTO). "We have parted ways with Barret Zoph," Murati wrote in her post. "Soumith Chintala will become the new CTO of Thinking Machines. He is a brilliant and experienced leader who has contributed to the field of artificial intelligence for more than a decade and has been a key member of our team."
However, Murati's announcement did not mention any other departures. It was only 58 minutes later that Fidji Simo, CEO of Applications at OpenAI, announced that Zoph, Metz, and Schoenholz were returning to OpenAI. "We are excited to welcome Barret Zoph, Luke Metz, and Sam Schoenholz back to OpenAI! This has been in the works for several weeks, and we’re thrilled to have them join the team," Simo wrote on X.
Excited to welcome Barret Zoph, Luke Metz, and Sam Schoenholz back to OpenAI! This has been in the works for several weeks, and we’re thrilled to have them join the team. Barret will report to me; Luke and Sam will report into Barret. More to come on what they’ll focus on soon!
— Fidji Simo (@fidjissimo) January 15, 2026
Allegations of Unethical Conduct
The circumstances surrounding Zoph's departure are shrouded in controversy. According to Wired, Zoph and Thinking Machines parted on bad terms. Technology reporter Kylie Robison was the first to report on X that Zoph had been fired for "unethical conduct." A source close to Thinking Machines claimed that Zoph had shared the company's confidential information with competitors. However, Wired was unable to verify this information directly with Zoph, who did not respond to a request for comment. According to an internal memo from Fidji Simo, Zoph told Mira Murati on Monday that he was considering leaving. He was subsequently fired on Wednesday. Simo stated in her memo that OpenAI did not share Murati's concerns about Zoph.
Who Are the Departing Co-Founders?
Barret Zoph worked at OpenAI as vice president of research and previously spent six years at Google as a research scientist. At OpenAI, he led teams that made final improvements to AI models before they were deployed in ChatGPT and OpenAI API products.
Luke Metz is another co-founder of Thinking Machines and previously worked on OpenAI's technical team for two years. He contributed to projects such as ChatGPT and the o1 artificial intelligence model focused on logical reasoning.
Sam Schoenholz, whose LinkedIn profile still lists Thinking Machines as his current employer, also spent several years at OpenAI.
From a Multibillion-Dollar Valuation to a Staffing Crisis
Thinking Machines Lab was founded by Mira Murati, who served as OpenAI's chief technology officer until September 2024. Zoph and Metz co-founded the startup with her. Since its inception, the company has secured massive financial backing—in July 2025, it closed an initial $2 billion funding round (approximately 47 billion Czech korunas) led by Andreessen Horowitz. Other investors included Accel, Nvidia, AMD, and Jane Street. The round valued the company at $12 billion (approximately 283 billion Czech korunas).
According to The Information, the company was recently in talks to raise more than $4 billion (approximately 94 billion Czech korunas) at a valuation of $50 billion (about 1.18 trillion Czech korunas). The startup's main product today is a tool called Tinker, which allows developers to customize AI models using their own datasets.
The simultaneous departure of two co-founders is an extraordinarily significant blow to a startup that has existed for less than a year. Losing two co-founders at once—especially when one of them served as chief technology officer—may be viewed as a particularly serious setback for Thinking Machines, which assembled a high-profile team of former researchers from OpenAI, Meta, and Mistral AI.
However, the company has also lost other key figures. Co-founder Andrew Tulloch left for Meta in October 2025. Interestingly, OpenAI itself has also seen the departure of many co-founders who went on to establish or join competing ventures. For example, John Schulman left for Anthropic in August 2024 before joining Thinking Machines as chief scientist in February of last year.
A Major Win for OpenAI
For OpenAI, the return of these three experts represents a significant boost. The company recently lost its vice president of research, Jerry Tworek, so the return of experienced researchers comes at the right time. According to Fidji Simo's memo, Zoph will report directly to her, while Metz and Schoenholz will work under his leadership. Simo told employees that the timeline for announcing the hires had been accelerated, so they still need to finalize some details regarding their roles.
