After joining with Mr. Musk to create OpenAI in 2015 and pledging to carefully develop artificial intelligence for the benefit of humanity, the suit claimed, Mr. Altman and Mr. Brockman abandoned this mission by entering its multibillion-dollar partnership with Microsoft.

The billionaire accused the ChatGPT maker of anticompetitive behavior in new court filings.

Elon Musk, an original co-founder of OpenAI, attempted to steer the organization away from becoming too cozy with Microsoft when it was negotiating an early cloud computing deal with the Redmond company.