Tech billionaire Elon Musk has branded OpenAI’s top executives “utterly untrustworthy assholes” after the company announced plans to withdraw its artificial intelligence models from Cursor following the coding platform’s acquisition by SpaceX.

Musk, who co-founded OpenAI in 2015 with its current CEO Sam Altman, President Greg Brockman, and several other developers and researchers, left the company three years later over its direction and has since been locked in a bitter public and legal feud with its leadership.

Earlier this month, SpaceX completed its $60 billion acquisition of Anysphere, the developer of Cursor, which provides programmers with access to AI models from several companies.

On Friday, OpenAI abruptly announced that it intends to end Cursor users’ access to its models, with a “proposed shutoff date” of November 12. The company said it could not be confident that “SpaceX will use our technology within our terms of service, based on our experience with Elon Musk’s companies violating contracts.”

“I couldn’t care less. Scam Altman and Greg Stockman are utterly untrustworthy assholes who stole an open source nonprofit,” Musk wrote on X on Saturday.

OpenAI models account for about 5% of Cursor’s user traffic, according to co-founder Michael Truell, who said the company was in talks with OpenAI to resolve the dispute. He noted that Cursor had been one of OpenAI’s earliest customers and said it had trusted the company’s platform to remain “neutral infrastructure” for its business.

OpenAI said its agreement with Cursor allows it to cancel the contract within a limited period following a change of control, although it has not accused the platform itself of violating its terms.

Anthropic, one of OpenAI’s main rivals, quickly moved to capitalize on the dispute, saying it would increase computing capacity to support its Claude models on Cursor following the cutoff announcement.

Musk, who initially invested an estimated $38 million in the venture, sued OpenAI in 2024, alleging that he had been misled into funding it on the understanding that it would remain a nonprofit. The company, now valued at about $850 billion, has since restructured, with its nonprofit parent retaining control of and a stake in its for-profit arm, which operates ChatGPT.

During court proceedings, Musk accused OpenAI of breaking that founding commitment by adopting a profit-driven model and entering a tight-knit alliance with Microsoft – a partnership that testimony revealed has cost Microsoft over $100 billion in infrastructure and direct funding. The billionaire has repeatedly accused Altman of having “stolen a charity” and described himself as a “fool” for providing the company with early financial support.

In May, a US federal jury rejected Musk’s claims, finding that he had waited too long to bring the case and had missed the statutory deadline. Musk has pledged to appeal the verdict.