Friday’s announcement by OpenAI comes soon after SpaceX completed its acquisition of Anysphere, the startup behind Cursor, for US$60 billion in an all-stock deal this month.
“We are making this choice because we cannot be confident that SpaceX will use our technology within our terms of service, based on our experience with Elon Musk’s companies violating contracts,” OpenAI said in a blog post.
Musk responded early on Saturday in an X post, writing, “I couldn’t care less.”
He accused Altman and OpenAI president Greg Brockman of being “untrustworthy,” while repeating his assertion that they “stole an open source nonprofit”.
Hours after OpenAI’s announcement, Anthropic, which rivals both firms but has an ongoing partnership with SpaceX, said it planned to increase compute to support Claude models in Cursor, according to Tom Brown, one of the co-founders of the firm.
However, Michael Truell, a co-founder of Cursor and now an executive at SpaceX, said that they were speaking with the OpenAI team to resolve this issue.
“Cursor was one of the very first users of OpenAI, we’ve worked closely with their team for years, and we’ve trusted their platform to be neutral infrastructure for our business,” Truell said in an X post on Friday.
Musk and Altman have been at odds for years, a feud that culminated in a trial.
During the trial, Musk’s lawyer said that Musk and other witnesses had testified that Altman was a liar, while OpenAI argued that Musk had sought control of the company.
Musk, the world’s richest person, had sued OpenAI for US$150 billion, accusing the company and Altman of “stealing a charity” by betraying its original nonprofit mission for their own enrichment.
A federal jury ruled against Musk this year, finding that he had filed the case too late.
In its blog post, OpenAI said that X, formerly known as Twitter and now part of SpaceX, had breached the terms of its contract with OpenAI after Musk acquired the platform.
“To work with a large partner like SpaceX, we typically rely on custom contracts to ensure compliance with our terms of service and that the integration provides for safety at scale,” the AI company added.
The ChatGPT-maker said it proposed a shutoff date of November 12, 2026, adding that its agreement with Cursor gave it a limited time window to cancel the contract following “a change of control”.
Cursor offers Grok models developed with SpaceXAI among its first-party models, while also allowing users to access frontier models from OpenAI, Anthropic and Google, according to its website. (Reuters)
