OpenAI is cutting Cursor off on November 12, and says the reason is trust

The date is November 12, 2026. That is when OpenAI's models stop working inside Cursor, under a change-of-control clause OpenAI invoked after SpaceX closed its acquisition of the editor, a deal we covered on August 20. OpenAI published the decision on Thursday under the plain title "Our decision on Cursor following its acquisition by SpaceX," and the stated reason is not performance or price. It is trust.

OpenAI's case is a list of receipts. After Musk bought Twitter in December 2022, the company terminated OpenAI's tweet-data licence, worth roughly $2 million a year, The Decoder reports. In litigation this year, Musk acknowledged that xAI trained Grok on competitor outputs, which OpenAI treats as a breach of its terms of use. "It comes down to trust," OpenAI's Thibault Sottiaux said of whether a SpaceX-owned Cursor would honour the conditions attached to model access.

Cursor's answer is a number. Co-founder Michael Truell put OpenAI's share of Cursor's AI traffic at about 5 percent and said the team is speaking with OpenAI to resolve the situation, which is not the language of a company treating the decision as final. Cursor users who bring their own OpenAI API keys are unaffected, since that traffic is billed to the individual rather than to Cursor. The product routes across several vendors: GPT-5.6 for coding, Anthropic's Claude models, which Latent Space's AINews calls the ones developers reach for first on code, and Grok 4.6 from the sibling company that now owns it.

The seventy-five days between announcement and cutoff are the interesting part. A coding tool that suddenly loses one vendor is a routing problem; a coding tool that watches a vendor leave because of who owns it is a structural one, and every AI product built on somebody else's models just learned that a change of ownership can end a supply relationship on legal grounds that have nothing to do with the product. If 5 percent is the true exposure, Cursor absorbs it. The question worth following is whether other model providers write the same clause into their own contracts, and whether the two companies talk their way out of this before November.