Key founders exit Mira Murati's AI venture to rejoin OpenAI
15 Jan 2026

Thinking Machines Lab, the AI start-up founded by former OpenAI executive Mira Murati, has lost two of its co-founders and another key team member to OpenAI.

The departures include Barret Zoph, the company's co-founder and CTO; Luke Metz, another co-founder; and Sam Schoenholz, a key team member.

Murati announced Zoph's departure on social media platform X. She said Soumith Chintala will replace him as the new CTO at Thinking Machines Lab.

Murati welcomes Chintala as new CTO
Leadership transition

In her post, Murati welcomed Chintala as the new CTO of Thinking Machines Lab. She described him as a "brilliant and seasoned leader" who has made significant contributions to the AI field for over a decade.

"We could not be more excited to have him take on this new responsibility," she added.

However, her announcement did not mention anything about Metz or other departures from the company.

OpenAI's CEO confirms Zoph and Metz's return
Talent acquisition

Just an hour after Murati announced Zoph's departure, OpenAI's CEO of applications Fidji Simo confirmed that Zoph will be returning to OpenAI.

She expressed her excitement over the development, saying, "Excited to welcome Barret Zoph, Luke Metz, and Sam Schoenholz back to OpenAI! This has been in the works for several weeks."

Murati's journey from OpenAI to Thinking Machines Lab
Career trajectory

Murati, who was the CTO of OpenAI until September 2024, left the company to co-found Thinking Machines Lab with Zoph and Metz.

The start-up has since raised significant funds, closing a $2 billion seed round last July.

The round was led by Andreessen Horowitz and saw participation from Accel, NVIDIA, AMD, and Jane Street, among others. It valued the company at $12 billion.

Implications of co-founders' departures
Market impact

The departure of co-founders from Thinking Machines Lab in less than a year since its inception is a major event.

The loss of two key leaders, especially one as high-profile as the CTO, could be seen as a major blow for the start-up.

Thinking Machines Lab had previously assembled an all-star team of ex-OpenAI, Meta, and Mistral AI researchers.

In October 2025, the company launched Tinker, an API designed to help researchers fine-tune language models with less code and hassle.