More recently, Murati oversaw major advancements to the company’s technology, including the May release of GPT-4o, the AI model that brought human-like, spoken conversations to ChatGPT, and this month’s preview of OpenAI o1, an AI model that the company says can “reason” to solve harder science and math problems.

“Our recent releases of speech-to-speech and OpenAI o1 mark the beginning of a new era of interaction and intelligence … We didn’t merely build smarter models, we fundamentally changed how AI systems learn and reason through complex problems,” Murati said in the note announcing her exit.

Murati said she is leaving OpenAI to “create time and space to do my own exploration” but that she would assist with the leadership transition.

OpenAI did not immediately respond to a question about the timeline for her formal exit for the company or when a new CTO would be announced.

OpenAI CEO Sam Altman responded to Murati’s X post with one of his own, saying, “It’s hard to overstate how much Mira has meant to OpenAI, our mission, and to us all personally.”

“I feel tremendous gratitude towards her for what she has helped us build and accomplish, but I most of all feel personal gratitude towards her for the support and love during all the hard times. I am excited for what she’ll do next,” Altman said, adding that the company would say more about the leadership transition plan soon.