OpenAI said it plans to stop supplying its AI models to Cursor, the coding platform now owned by Elon Musk’s SpaceX, escalating the long-running dispute between Musk and OpenAI CEO Sam Altman.

OpenAI said it could no longer be confident that SpaceX would use its technology in accordance with contractual terms, citing previous disputes involving Musk-controlled companies.

The company has proposed November 12, 2026 as the cutoff date. OpenAI said its agreement with Cursor allows it to terminate the relationship within a limited period following a change in ownership.

SpaceX completed its acquisition of Anysphere, the company behind Cursor, earlier this month after agreeing to a $60 billion all-stock deal in June.

Cursor co-founder Michael Truell, now a SpaceX executive, said the company was discussing the issue with OpenAI in an effort to reach a resolution.

Meanwhile, rival AI developer Anthropic said it plans to increase computing capacity for its Claude models inside Cursor, potentially reducing the impact of OpenAI’s withdrawal.

The dispute adds another layer to the increasingly public rivalry between Musk and OpenAI. Musk previously sued OpenAI and Altman over allegations that the company abandoned its original nonprofit mission, though a federal jury ruled against him earlier this year.