OpenAI will cut SpaceX's (SPCX) Cursor off from its models on November 12. Musk: "I couldn't care less... utterly untrustworthy assholes"

SpaceX Cursor and OpenAI logos over the November 12 model shutoff

Key points

  • OpenAI notified SpaceX on Friday, August 28 that it will wind down Cursor's access to its models, proposing a November 12, 2026 shutoff, the maximum notice its contract allows.
  • Cursor CEO Michael Truell said OpenAI models serve about 5% of Cursor user traffic, and Anthropic's Tom Brown said Claude compute for Cursor will keep increasing.
  • SpaceX (SPCX) closed Friday at $141.47, little changed, two weeks after completing its $60 billion all-stock purchase of Cursor's parent Anysphere.

OpenAI said Friday it has notified SpaceX (SPCX) that it will wind down the contract that puts OpenAI models inside Cursor, the AI coding editor SpaceX bought two weeks ago. The proposed shutoff date is November 12, 2026, which OpenAI called the maximum notice its contract allows. "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 wrote.

OpenAI said its custom agreement with Cursor "gives us a limited time window to cancel it after a change of control," and that future models, including its upcoming Astra, will not be offered in Cursor at all. The post pointed to two earlier episodes. OpenAI says Twitter broke its contract terms after Elon Musk acquired it, and that Musk acknowledged under oath this year that xAI had violated OpenAI's terms of service. Both companies are now part of SpaceX.

Cursor says OpenAI is about 5% of its traffic

Michael Truell, Cursor's co-founder and CEO, wrote on X that Cursor was "sorry to see" the announcement. "OpenAI models serve about 5% of Cursor user traffic, and we're speaking with the OpenAI team to resolve this," he said.

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Musk replied to a fan account on X, calling the pair "utterly untrustworthy assholes" who he said "stole an open source nonprofit." The names in his post, "Scam Altman" and "Greg Stockman," refer to OpenAI CEO Sam Altman and president Greg Brockman.

Anthropic, which was reported to be days from an IPO filing on August 21, answered within hours. Tom Brown, its co-founder and chief compute officer, posted: "Cursor has been a trusted partner of Anthropic since Sonnet 3.5. We'll continue to increase compute to support Claude models in Cursor and are excited for what comes next with them at SpaceX."

SpaceX shares and the deal

SpaceX closed Friday at $141.47, up from Thursday's $140.87 close, and was little changed in after-hours trading. The company completed its $60 billion all-stock purchase of Cursor's parent Anysphere in mid-August, the largest acquisition of a venture-backed startup on record. Cursor's business was reported at about $2.6 billion in annualized revenue when the deal was announced, and twenty hedge funds disclosed $35 billion of SpaceX stock in the August 13F round.

"We've worked with Cursor for nearly four years and have enormous respect for their team, their product, and what they've built for the developer community," it wrote, adding that it is "ready to go above and beyond to support them" through the transition.

Sources

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Frequently asked questions

When does Cursor lose access to OpenAI models?

OpenAI proposed a shutoff date of November 12, 2026, which it says is the maximum notice allowed under its contract. OpenAI notified SpaceX on August 28, 2026, about two weeks after SpaceX completed its $60 billion acquisition of Cursor's parent company, Anysphere.

Why is OpenAI ending its Cursor partnership?

OpenAI says it cannot be confident SpaceX will use its technology within its terms of service, citing its experience with Elon Musk's companies. It says Twitter broke its contract terms after Musk acquired it and that Musk acknowledged under oath in 2026 that xAI had violated OpenAI's terms. Its agreement with Cursor allows cancellation within a window after a change of control.

How dependent is Cursor on OpenAI models?

Cursor co-founder and CEO Michael Truell said on August 29, 2026 that OpenAI models serve about 5% of Cursor user traffic, and that Cursor is speaking with OpenAI to resolve the dispute. Anthropic's Tom Brown said Anthropic will continue to increase compute for Claude models in Cursor.

How did SpaceX (SPCX) stock react?

SpaceX closed at $141.47 on Friday, August 28, 2026, up slightly from the prior close of $140.87, and was little changed after hours. OpenAI's announcement was published that evening, so Monday, August 31 is the first full session to price the news.

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Dennis Singleton
Dennis Singleton

Dennis Singleton has spent years following the markets, but what keeps his attention is how AI is built. He writes about the companies behind the technology, from semiconductor designers and advanced packaging to photonics, memory, networking, and the hardware powering modern AI. His approach starts with filings, earnings, and industry research, then translates the important details into clear, straightforward analysis without unnecessary hype.