OpenAI cuts Cursor off. Cursor says that's 5% of traffic

OpenAI told SpaceX it is winding down the contract that supplies GPT models to Cursor, with a cutoff of November 12. The trigger is a change-of-control clause that fired when SpaceX closed its $60B all-stock acquisition of Anysphere on August 14 — the largest startup acquisition on record, roughly 391 million SpaceX Class A shares. OpenAI's stated reason is blunt: it "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."

Cursor CEO Michael Truell replied with a number instead of a lawsuit — OpenAI models are about 5% of Cursor traffic. The other 95% runs on Cursor's in-house Composer model plus Anthropic, Google and xAI. Anthropic has not followed OpenAI out the door: Claude stays in the editor and Anthropic says it is adding compute to serve it. Which fits the backdrop — SpaceXAI dropped Grok Bot into Cursor Premium Teams at $120/seat/month on August 11, days before the deal closed, so the vertical stack was already being assembled.

The uncomfortable part for everyone else building on rented models: this was not a pricing dispute or an abuse case. A supplier terminated over who bought the customer.

Why it matters: model access is now a competitive weapon — if your vendor is also your acquirer's rival, your model menu is one term sheet away from shrinking.