OpenAI has announced it is severing ties with the coding startup Cursor, claiming it can no longer trust an organization owned by Elon Musk to follow its rules. The move comes shortly after SpaceX acquired Cursor in a massive sixty billion dollar deal. In a statement released Friday night, OpenAI revealed it will shut off Cursor’s access to its artificial intelligence models on November 12, admitting the decision was difficult but necessary given their history with Musk’s other ventures.

Interestingly, OpenAI did not claim that Cursor itself broke any rules. Instead, the company pointed toward a pattern of behavior across Musk’s broader empire, specifically mentioning previous contractual disputes involving Twitter. OpenAI also highlighted testimony where Musk admitted his own AI venture, xAI, likely used outputs from OpenAI models to train its Grok system. Because these custom partnerships often include specific windows for cancellation during acquisitions, OpenAI decided now was the time to pull the plug before further integration occurred.

The fallout creates immediate uncertainty for Cursor users who rely on high end models like GPT-5.6 Luna and Sol to write code. While Cursor integrates tools from various providers including Google and Anthropic, the loss of OpenAI’s current and future models, such as the upcoming Astra, represents a significant blow to its feature set. Neither SpaceX nor OpenAI have offered additional comments beyond the official statements regarding how existing subscribers will be impacted come mid-November.

This clash marks yet another chapter in the bitter rivalry between Musk and the company he helped found years ago. Since leaving the board and later suing Sam Altman over OpenAI’s transition from a nonprofit to a commercial powerhouse, Musk has remained locked in legal battles with his former colleagues. Although a federal jury recently ruled against him due to timing issues with his lawsuit, Musk intends to appeal, ensuring that the tension between these two titans of industry remains far from resolved.