OpenAI announced it will end Cursor's access to its models on November 12, following Space Exploration Technologies Corp. (SPCX) $60 billion all-stock acquisition of Cursor's parent company, Anysphere, which closed on August 14. OpenAI cited concerns that SpaceX might use its technology outside of service terms, referencing past contract disputes with Elon Musk's other companies like X and xAI. Cursor CEO Michael Truell stated that OpenAI models account for only about 5% of Cursor's user traffic. Musk responded on X, calling OpenAI's leadership "utterly untrustworthy." Anthropic co-founder Tom Brown said his company would increase compute to support Claude models in Cursor.