SAN FRANCISCO (AP) — OpenAI co-founder Ilya Sutskever, one of the original creators of the artificial intelligence technology behind ChatGPT, said Tuesday he is leaving the company after a nearly decade.

Sutskever was one of four board members last fall who voted to push out CEO Sam Altman from the company — only to quickly reinstate him. It was Sutskever, OpenAI’s chief scientist, who told Altman last November that he was being fired.

Sutskever announced his decision on the social media site X. He said he is working on a new project that is “very personally meaningful” to him, but he offered no other details.

Altman, meanwhile, wrote that parting ways is “very sad” and called Sutskever “one of the greatest minds of our generation, a guiding light of our field, and a dear friend.”

Sutskever will be replaced by Jakub Pachocki as chief scientist at San Francisco-based OpenAI. Altman called Pachocki “also easily one of the greatest minds of our generation” and said he is “very confident he will lead us to make rapid and safe progress towards our mission of ensuring that AGI benefits everyone.”

Short for artificial general intelligence, AGI is a futuristic vision of machines that are as broadly smart as humans or at least can do many things as well as people can.

On Monday, OpenAI introduced an update to its AI model it says can reason across text, audio and video in real time.

The Associated Press and OpenAI have a licensing and technology agreement that allows OpenAI access to part of the AP’s text archives.