OpenAI is terminating API access for Cursor (a code editor acquired by SpaceX in June for $60 billion) effective November 12, 2026, citing lack of confidence that SpaceX will comply with terms of service based on past contract violations by Musk's companies. The source specifically names X/Twitter as having breached OpenAI's contract after Musk's acquisition. Musk dismissed the move publicly. Cursor's co-founder says they're negotiating with OpenAI, while Anthropic (Claude's maker) announced it will increase compute support for its own models in Cursor as a competitive response. The decision legally hinges on a contract clause allowing cancellation following "change of control." For practitioners: this is a high-profile API cutoff with clear stated rationale (compliance risk), a defined end date, and immediate competitive repositioning by a rival LLM provider. The underlying lawsuit context (Musk's failed $150B case against OpenAI earlier in 2026) provides friction history but doesn't appear to be the direct legal trigger here. One question worth tracking: what specific past violations by SpaceX or Tesla is OpenAI referencing, since the source doesn't enumerate them?