OpenAI said it's ending its contract with Cursor, a coding startup recently acquired by SpaceX, because it doesn't trust an Elon Musk-owned company to comply with its terms of service.

The company said in a statement published on Friday night that it plans to shut off Cursor's access to OpenAI models on November 12.

"This decision was incredibly tough, as we care deeply about our models being broadly available for developers," OpenAI said. "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."

Spokespeople for SpaceX and OpenAI did not immediately return a request for comment.

OpenAI did not accuse Cursor of violating any terms. It instead pointed to past conduct by another Musk-owned company, Twitter, which Musk bought in 2022 and merged with SpaceX earlier in February.

OpenAI said in its blog post that Twitter had previously violated the terms of its contract, citing a New York Times story reporting that Musk cut off OpenAI's access to Twitter's data. OpenAI also wrote that the SpaceX CEO said under oath earlier this year that xAI had violated OpenAI's terms by training Grok from OpenAI's output.

Musk said at the time that it was "partly" true that xAI had distilled OpenAI's models, The Verge reported in April.

OpenAI said that it uses "custom contracts" with large partners like SpaceX to ensure compliance. The partnership OpenAI had with Cursor provided a "limited time window" to cancel the agreement after the acquisition, the company said.

SpaceX officially acquired Cursor this month for $60 billion. The deal gives the coding startup access to SpaceX's computing power.

Explore BI Games Take a smarter break in your day - and see how far you get. Play now Want more Business Insider in your news feed? Add BI in Google so our reporting is easier to find when you’re searching for what matters. Add to Preferred Sources

Cursor, an AI coding editor, offers models from several companies inside its software, including OpenAI, Anthropic, Google, and SpaceXAI. Its website lists OpenAI's GPT-5.6 Luna, Sol, and Terra models that paid users can access through its software.

It's unclear which Cursor users or models will be affected by the shutdown. OpenAI said that it will not provide "future models" to Cursor, including its coming Astra model.

The decision is the latest escalation in the long-running feud between Musk and OpenAI.

In 2024, Musk, an OpenAI cofounder and early backer, sued the company, its CEO, Sam Altman, and others over its shift from a nonprofit research lab to a partially for-profit entity.

In May, a federal jury found that Musk waited too long to bring the case forward, missing the statute of limitations.

Musk said he plans to appeal the decision.