OpenAI ends relationship with Cursor following the SpaceX acquisition; makes it clear Elon Musk is the ‘big reason’; says: Starting November 12…
OpenAI is pulling its models out of Cursor, and it is not being coy about why. The company told SpaceX on Friday that it intends to wind down the contract supplying OpenAI models to the popular AI coding tool, with a proposed shutoff date of November 12, 2026. There is no dispute here about pricing, performance or usage limits. The stated reason is Elon Musk, and OpenAI put that in writing in a public blog post rather than letting it leak out through a support page.The trigger is ownership. SpaceX agreed in June to buy Anysphere, the startup behind Cursor, in an all-stock deal valued at $60 billion, and closed it earlier this month. OpenAI’s agreement with Cursor carried a change-of-control clause that opened a short cancellation window, and OpenAI used it. The company said it cannot be confident SpaceX will operate within its terms of service, citing what it described as a pattern of Musk’s companies breaking contracts.
OpenAI says it has been burned by Musk’s companies before
The blog post lays out the receipts. OpenAI claims that X, formerly Twitter and now folded into SpaceX, broke the terms of its contract after Musk took over the platform. It also points to sworn testimony this year in which Musk acknowledged that xAI, likewise now part of SpaceX, had violated OpenAI’s terms of service. OpenAI added that its forthcoming model, Astra, raises the accountability bar further, which is why it would rather end the arrangement than extend it to a partner it does not trust. It says it gave the maximum notice its contract allows so developers get time to plan.
Cursor says OpenAI models handle only 5% of its traffic
Michael Truell, the Cursor co-founder who is now a SpaceX executive, responded on X with a mix of disappointment and math. He said OpenAI models account for roughly 5% of Cursor’s user traffic, and that his team is talking to OpenAI to resolve the situation. Truell also noted that Cursor was one of OpenAI’s earliest customers and had treated the platform as neutral infrastructure. That framing matters, because the practical damage looks small. Cursor shipped Grok 4.6 on Wednesday, its first model built with SpaceX compute behind it.OpenAI, for its part, is leaving side doors open. Thibault Sottiaux, who works on the Codex coding tool, said developers can keep using their own OpenAI API keys and will still get access through OpenAI’s IDE extensions for Cursor.
Anthropic moves in while Musk shrugs the whole thing off
Within hours, Anthropic filled the gap. Co-founder and chief compute officer Tom Brown said the company has partnered with Cursor since Sonnet 3.5 and will increase compute to support Claude models inside the editor. Musk replied to that post with two rocket emojis.His response to OpenAI was less warm. He said he could not care less about the cutoff, called Sam Altman and Greg Brockman untrustworthy, and repeated his claim that they took an open source nonprofit for themselves. That argument already had its day in court this year, when a federal jury rejected his $150 billion suit against OpenAI on the grounds that he filed it too late.So the developers losing GPT access in Cursor on November 12 are collateral in a fight that started long before anyone wrote a line of code in it.
