Two Thinking Machines Lab Cofounders Return to OpenAI
Key Points
- Barret Zoph and Luke Metz leave Thinking Machines Lab to rejoin OpenAI.
- OpenAI applications chief Fidji Simo announced the moves in an internal memo.
- A source alleged Zoph was dismissed for sharing confidential information; OpenAI did not verify this claim.
- Mira Murati confirmed Zoph’s departure and appointed Soumy Chintala as the new CTO of Thinking Machines Lab.
- Sam Schoenholz also returns to OpenAI alongside Zoph and Metz.
- The departures follow earlier cofounder Andrew Tulloch’s move to Meta.
- Thinking Machines Lab continues to develop its Tinker platform for customizing AI models.
Barret Zoph and Luke Metz, cofounders of the AI startup Thinking Machines Lab, have left the company to rejoin OpenAI. The move was announced by OpenAI’s applications chief Fidji Simo in an internal memo. A source alleged that Zoph was dismissed for sharing confidential information, a claim OpenAI did not verify. Mira Murati confirmed Zoph’s departure and named Soumith Chintala as the new chief technology officer. The departures also include Sam Schoenholz, who is returning to OpenAI, and follow the earlier exit of cofounder Andrew Tulloch to Meta. Thinking Machines Lab continues to develop its Tinker platform for customizing AI models.
Background
Thinking Machines Lab was founded by former OpenAI leaders, including Barret Zoph, Luke Metz and Mira Murati, after they left OpenAI in late 2024. The startup focuses on a product called Tinker, which lets developers tailor AI models with their own data. Prior to starting the company, Zoph served as OpenAI’s vice president of post‑training, overseeing final improvements to models before they reached products such as ChatGPT. Metz spent two years at OpenAI during his first stint, contributing to projects like ChatGPT and the o1 reasoning model.
Departures and Re‑entries
In a memo to staff, OpenAI’s applications chief Fidji Simo announced that Zoph and Metz are leaving Thinking Machines Lab to rejoin OpenAI. The memo noted that Zoph will report directly to Simo, while Metz and Sam Schoenholz will work under him. A source close to Thinking Machines alleged that Zoph was dismissed for sharing confidential company information with competitors, a claim that OpenAI could not verify. Murati confirmed Zoph’s exit and said that Soumy Chintala will replace him as the startup’s chief technology officer.
The announcement also noted that Sam Schoenholz, a third Thinking Machines employee, is returning to OpenAI. This shift follows the earlier departure of another cofounder, Andrew Tulloch, who left the startup to take a new role at Meta.
Implications for the AI Landscape
The return of two senior AI researchers to OpenAI is seen as a notable win for the company, especially after it recently lost its vice president of research. The move underscores the fluid nature of talent among top AI organizations, where founders and senior engineers often shift between established labs and new ventures. While Thinking Machines Lab continues to advance its Tinker platform, the leadership changes may affect its short‑term development timeline.
OpenAI’s decision to bring back Zoph and Metz, despite the allegations surrounding Zoph’s departure from Thinking Machines, suggests the company does not share the same concerns raised by Murati. The re‑integration of these researchers could strengthen OpenAI’s ongoing efforts to refine and deploy advanced AI models across its product suite.