Sam Altman Is Tearing Apart His Former Colleague’s Startup

The AI industry’s talent-poaching war is heating up, and it’s starting to seem personal.

This week, two Thinking Machines Lab co-founders, Barret Zoph and Luke Metz, left the startup to rejoin OpenAI. And more defections are reportedly on the way.

In case you’re not familiar, Thinking Machines is an AI startup founded by OpenAI’s former chief technology officer, Mira Murati, in 2025. The company closed a $2 billion seed round this past summer, which included Andreessen Horowitz, Nvidia, and AMD, and valued the company at $12 billion. Later that year, it launched Tinker, an API for fine-tuning large language models.

Tech reporter Kylie Robinson was first to report Wednesday that Zoph had been terminated from his role as CTO at Thinking Machines over “unethical conduct,†citing unnamed sources. Murati later confirmed his departure in a post on X.

Roughly an hour after that post, OpenAI CEO of Applications Fidji Simo announced in her own post on X that Zoph would be rejoining OpenAI, along with Metz and another Thinking Machines staffer, Sam Schoenholz.

“This has been in the works for several weeks, and we’re thrilled to have them join the team,†wrote Simo.

Behind the scenes, things were apparently messier. In a memo to staff obtained by Wired, Simo wrote that Zoph told Murati on Monday that he was considering leaving the company. He was fired two days later. Sources close to Thinking Machines told Wired that Zoph allegedly shared confidential information with the startup’s rivals. Simo added in the memo that OpenAI does not share Murati’s concerns regarding Zoph.

Unfortunately for Thinking Machines, more departures are expected. Alex Heath reported in his Substack that additional Thinking Machines staffers are in talks to jump ship to OpenAI.

This is the latest example of the revolving door AI startups have become in recent years, with researchers, staffers, and even co-founders jumping back and forth between companies. Just last year, Meta made headlines for spending millions to lure talent from OpenAI over to its AI team; however, it only took less than a month for some researchers to return to OpenAI.

But what makes this saga especially intriguing is the history. Murati, Zoph, and Metz all previously worked at OpenAI, and Murati allegedly played a big role in OpenAI CEO Sam Altman’s brief ouster in 2023.

The Wall Street Journal reported last year that Murati provided Slack screenshots that were used to expose Altman’s alleged leadership issues and ethical lapses to OpenAI’s board at the time. She also served as the company’s interim CEO during the brief time when OpenAI was rudderless.

After Altman was reinstated, Murati returned to her role as CTO before later announcing in 2024 that she was stepping away to “create the time and space to do my own exploration.†She then founded Thinking Machines with Zoph and Metz.

Yet, even in an industry known for rapid job-hopping, it’s still surprising that half of the Thinking Machine’s co-founders have already left in such a short period of time. One of them, Andrew Tulloch, departed for Meta last fall.

OpenAI and Thinking Machines did not immediately respond to requests for comment from Gizmodo.