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.
We’re ending our partnership with Cursor following its acquisition by SpaceX. Under our proposal, Cursor’s direct access to our models would end on November 12.
See OpenAI’s post on X
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.
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.
I couldn’t care less. Scam Altman and Greg Stockman are utterly untrustworthy assholes who stole an open source nonprofit.
See Elon Musk’s post on X
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.
