Thinking Machines Lab, the AI startup founded by former OpenAI CTO Mira Murati, has parted ways with co-founder and CTO Barret Zoph, according to statements shared internally and on social media.

Murati announced the leadership change at an all-hands meeting and on X, naming longtime AI researcher Soumith Chintala as the company’s new CTO. Chintala is a former Meta AI researcher and a core contributor to the PyTorch framework.

Separately, OpenAI Applications CEO Fidji Simo confirmed that Barret Zoph, along with Luke Metz and Sam Schoenholz, will be returning to OpenAI. Simo stated the move had been in discussion for several weeks, with Zoph reporting directly to her.

TechCrunch reported, citing sources familiar with the matter, that Zoph’s departure followed internal concerns related to conduct, though Thinking Machines did not publicly detail the allegations. The company emphasized continuity in leadership and execution.

The change marks the third co-founder departure from Thinking Machines in under a year, following Andrew Tulloch’s move to Meta in late 2025.

Why it matters: Talent movement at the frontier of AI remains highly fluid, with leadership shifts reshaping young labs and established players alike. The episode underscores how governance, trust, and people—not just models—continue to play a defining role in the AI ecosystem’s evolution.