OpenAI has severed its relationship with Cursor, an AI coding editor, after SpaceX completed a USD 60 billion acquisition of Cursor's parent company Anysphere on August 14. The termination notice, sent on August 28, marks a dramatic escalation in the long-running dispute between Elon Musk and OpenAI co-founders Sam Altman and Greg Brockman. The contract will wind down by November 12, with OpenAI supplying no new models during the transition period.

The decision reflects far more than a routine business disagreement. OpenAI stated it could not be confident that SpaceX would use its technology within its terms of service, citing what it described as a history of contract breaches at Musk-owned businesses. The company pointed specifically to Twitter's conduct after Musk's 2022 takeover and, more pointedly, to Musk's own admission under oath earlier this year that xAI had violated OpenAI's terms of service.

Why Did OpenAI Really Pull the Plug?

The termination hinges on three key factors that reveal the depth of mistrust between the parties. First, OpenAI cited its forthcoming model, Astra, which the company said in August may reach a critical cyber capability threshold under its own preparedness framework. This concern about advanced AI capabilities falling into potentially unreliable hands prompted OpenAI to tighten control over model distribution. Second, Cursor's custom agreement with OpenAI included only a narrow window to cancel following a change of control, which OpenAI used in full. Third, the acquisition itself triggered the clause; Anysphere was among OpenAI's earliest customers, and the two had worked together for close to four years before SpaceX's involvement.

Cursor co-founder Michael Truell, now a SpaceX executive, responded with measured language, noting that OpenAI models account for roughly 5% of Cursor traffic and that discussions were underway. Musk, however, was unsparing. On X, he said he could not care less, described Altman and Brockman as untrustworthy, and repeated his charge that the pair took an open source nonprofit and converted it for personal gain.

Within hours, Anthropic moved to capitalize on the rift. Co-founder Tom Brown signaled additional compute resources for Claude models inside Cursor, positioning Anthropic's AI assistant as a replacement for OpenAI's technology.

How Did This Decade-Long Feud Begin and Escalate?

Understanding the intensity of this contract termination requires stepping back to 2015, when Musk and Altman founded OpenAI together as a nonprofit with an explicit mission: to prevent advanced artificial intelligence from ending up under the control of any single company. Musk contributed tens of millions of dollars to the effort. By 2017, however, the founders concluded they could neither raise the capital nor recruit the researchers needed to compete without a commercial arm. Musk accepted this diagnosis but wanted the solution on his own terms, proposing either a majority stake in the for-profit entity or folding the entire operation into Tesla. Altman, Brockman, and Ilya Sutskever refused. Musk left the board in 2018, took talent with him, and stopped the donations he had promised.

The grievance remained largely private for five years before erupting into public view in July 2023 with the launch of xAI, Musk's own artificial intelligence company. The dispute became litigious in February 2024 when Musk sued in California state court. He withdrew that case in June and refiled in federal court in August, alleging that Altman and Brockman had manipulated him into bankrolling a charity they then converted for personal enrichment.

January 2025 added what Musk viewed as a personal insult. Altman appeared alongside Donald Trump to announce Stargate, a USD 500 billion AI infrastructure program, without warning Musk, who was by then running the Department of Government Efficiency. Weeks later, a Musk-led consortium bid USD 97.4 billion for OpenAI's assets. The board rejected the offer within hours. Altman replied on X with an offer to buy Twitter for USD 9.74 billion, a number chosen for the joke.

What Legal Battles Are Currently Underway?

The conflict has spawned multiple lawsuits across different jurisdictions and legal theories. Here is the current landscape of litigation:

• OpenAI's Counterclaim: OpenAI countersued in April 2025, calling Musk's USD 97.4 billion bid a feint and describing a sustained campaign of harassment waged through press attacks, a pretextual records demand, and posts to more than 200 million followers on a platform Musk owns. A judge let these counterclaims proceed in August 2025, and they remain active.
• xAI's Antitrust Case: In August 2025, xAI and X sued Apple and OpenAI in Texas, arguing that the Siri partnership made it impossible for any rival assistant to reach the top of the App Store. This case survived dismissal in November 2025 and continues to move forward.
• xAI's Trade Secrets Suit: A month after the antitrust filing, xAI sued OpenAI over engineer poaching and trade secrets. That case was dismissed in February 2026 with leave to amend, dismissed again in June without it, and is now before the Ninth Circuit.

What Does This Mean for the Broader AI Industry?

The Cursor termination signals that the Musk-Altman rivalry has moved beyond courtroom disputes into operational business decisions. OpenAI's willingness to sever a nearly four-year customer relationship over ownership concerns demonstrates how deeply the company's leadership distrusts Musk's intentions. The move also reflects OpenAI's confidence in its market position; the company can afford to lose a customer representing roughly 5% of Cursor's traffic because it believes the loss will not materially impact its business.

For Cursor users and developers, the immediate impact is manageable. Anthropic's rapid offer of additional Claude compute suggests that switching costs are low and alternatives are readily available. However, the broader implication is more significant: major AI companies are now willing to make business decisions based on ownership and control concerns, not just performance or pricing. This sets a precedent that could reshape how AI model providers evaluate partnerships with companies owned by figures they view as adversarial.

The termination also underscores the stakes in the broader AI competition. OpenAI's reference to Astra's potential to reach critical cyber capability thresholds suggests the company views its most advanced models as strategic assets that require careful gatekeeping. In a landscape where artificial intelligence is increasingly seen as a national security concern, OpenAI's decision to restrict access based on trust rather than technical merit reflects how geopolitical and interpersonal dynamics now shape the distribution of AI technology.