OpenAI ends Cursor's access to its AI models after SpaceX deal

OpenAI said on Friday that it will stop providing its AI models to Cursor, the AI coding assistant made by Anysphere, now that the startup has been bought by Elon Musk's SpaceX, according to Reuters. The announcement marks a fresh escalation in the long-running rivalry between OpenAI chief executive Sam Altman and Musk, a dispute that this year produced a trial over Musk's 150-billion-dollar lawsuit against OpenAI.

A pattern OpenAI says it has seen before

In a blog post cited by Reuters, OpenAI explained its reasoning bluntly: "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." The company pointed to X, the social network formerly known as Twitter and now part of SpaceX, which it said had breached the terms of its own contract with OpenAI after Musk acquired the platform. According to the trade outlet OfficeChai, OpenAI's post also referenced Musk's sworn testimony earlier this year, in which he admitted that xAI, his own AI company, had violated OpenAI's terms of service.

The November 12 deadline

OpenAI said it had notified SpaceX of its intent to end the arrangement, proposing a shutoff date of November 12, 2026 — what the company describes, per OfficeChai, as the maximum notice period allowed under its contract with Cursor. OpenAI added, in comments reported by Reuters, that "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." OfficeChai reported that OpenAI tied part of its reasoning to the safety obligations attached to its next model, referred to internally as Astra, saying it now carries a higher level of responsibility for how that model is used downstream once it ships.

• June 2026: SpaceX announces an all-stock deal to acquire Anysphere, the company behind Cursor, for 60 billion dollars.
• Early August 2026: SpaceX completes the acquisition.
• August 28, 2026: OpenAI notifies SpaceX that it intends to wind down Cursor's access to its models.
• November 12, 2026: the shutoff date OpenAI has proposed.

Cursor says the impact will be limited

Cursor co-founder Michael Truell, now an executive at SpaceX following the acquisition, responded within hours on X, according to OfficeChai. He said Cursor was disappointed by the notice and was in talks with OpenAI to try to resolve the issue, while noting that OpenAI's models account for roughly 5% of Cursor's total user traffic — a figure that limits, in his telling, the disruption the cutoff would cause. Truell also recalled that Cursor had trusted OpenAI's platform to function as neutral infrastructure for its business ever since Anysphere took seed funding from the OpenAI Startup Fund back in 2023.

Musk fires back, and a rival steps in

Musk responded on X, according to Reuters, accusing Altman and OpenAI president Greg Brockman of being "untrustworthy" and repeating his long-standing claim that they "stole an open source nonprofit" — a reference to his unsuccessful 150-billion-dollar lawsuit against OpenAI, which a federal jury rejected earlier this year after ruling that Musk had filed the case too late. Hours after OpenAI's announcement, Anthropic — a rival to both OpenAI and xAI, but a company with its own commercial ties to SpaceX — said it planned to increase the computing capacity it dedicates to running Claude models inside Cursor, Reuters reported, citing Anthropic co-founder Tom Brown.

Not the first time a model maker has pulled the plug

OpenAI's move echoes a decision Anthropic made roughly a year earlier, according to OfficeChai: Anthropic cut off the coding tool Windsurf's direct access to Claude models within days of reports that OpenAI itself was about to acquire the startup, leaving Windsurf to scramble for third-party computing capacity. Anthropic's Jared Kaplan later explained the move at a conference by saying it would be "odd" for Anthropic to keep selling its models to a company about to be owned by its biggest rival — a more openly competitive rationale than the compliance-based one OpenAI has now given for Cursor.

The stakes are also different in scale. OfficeChai reported that Anysphere's revenue crossed 3 billion dollars on an annualized basis earlier this year, built in part on a 29.3-billion-dollar Series D funding round whose backers included both Nvidia and OpenAI — an awkward detail, OfficeChai noted, given that OpenAI is now an investor pulling model access from a company in which it also holds a stake.

For American software teams and startups building on foundation-model APIs, the episode is a reminder that access to an AI model is never permanently guaranteed: a "change of control" clause can be invoked well before a deal even closes, and diversifying model providers — as Cursor itself is now doing by leaning more on Anthropic's Claude — has become as much a business-continuity decision as a technical one.