OpenAI has ended its model-supply agreement with Cursor, the AI coding tool now owned by SpaceX. On August 28, 2026, in a company blog post, OpenAI said it proposed a shutoff date of November 12, 2026, and would not deliver future models, including its coming Astra model. The decision lands 14 days after SpaceX completed its $60 billion all-stock acquisition of Anysphere, Cursor’s parent company, effective August 14, 2026, according to financial filings cited by CNBC. Anysphere, founded in 2022, raised $3.4 billion from investors including Andreessen Horowitz, Thrive Capital, Accel, Coatue and the OpenAI Startup Fund before the deal. The step-up from the $29.3 billion Series D price of November 2025 to $60 billion is $60,000M ÷ $29,300M = 2.0×.

Reuters reported on August 29, 2026 that OpenAI plans to stop providing AI models to Cursor. OpenAI framed the decision in contractual terms, saying it lacked confidence that SpaceX would use its technology within its terms of service, and that X, now part of SpaceX, had breached its OpenAI contract after Musk acquired the platform. The company said it typically relies on custom contracts with large partners to ensure compliance and safety at scale, and that its Cursor agreement gave it a limited window to cancel following a change of control. The notice came 14 days after the August 14, 2026 closing, indicating the clause was exercised early in that window. The commercial break follows a legal one: a jury rejected Musk’s 2024 claims against OpenAI, Altman and Brockman on May 18, 2026.

Model supply becomes leverage

Anthropic moved within hours. Tom Brown, a co-founder of Anthropic, said the company planned to increase compute to support Claude models in Cursor, according to Reuters. Anthropic competes with both OpenAI and xAI, the Musk-founded lab SpaceX acquired in February 2026, yet keeps an ongoing partnership with SpaceX, whose Colossus supercomputer it rents alongside Google, according to TechCrunch. Cursor’s editor already ships models from OpenAI, Anthropic, Google and SpaceXAI, and lists OpenAI’s GPT-5.6 Luna, Sol and Terra for paid users, according to Business Insider. Michael Truell, a Cursor co-founder who is now a SpaceX executive, said on X that the company was speaking with the OpenAI team to resolve the issue, according to Reuters. “We are making this choice because we 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,” OpenAI said in its blog post on August 28, 2026.

Capital stack and revenue multiples

OpenAI’s position is contractual: a $60 billion acquisition it did not fund and a change-of-control clause it could exercise. Anysphere’s cap table before the deal lists Andreessen Horowitz, reportedly holding roughly a 10% stake worth $6 billion, and Thrive Capital at about 7% and $4.2 billion, alongside Accel and Coatue, which priced the Series D at $29.3 billion in November 2025, according to Forbes. Revenue figures diverge by source and are not averaged: $1 billion annualized in November 2025 per a release cited by CNBC, more than $2 billion by February 2026 per Forbes, and an estimated $4 billion annualized for 2026, also per Forbes. At $4 billion, $60,000M ÷ $4,000M = 15.0×; at $2 billion, $60,000M ÷ $2,000M = 30.0×, both inside the 5-100× band typical for enterprise software. OpenAI licenses models to developer tools; SpaceX rents compute to AI labs and ships its own coding agent, Grok Build.

For software developers, the November 12, 2026 cutoff means re-platforming away from GPT-5.6 Luna, Sol and Terra inside Cursor, or shifting work to Claude, Google’s models or xAI’s Grok Build. For model providers, it means distribution contracts now carry counterparty risk priced in legal terms, not only in tokens and latency. For enterprise buyers, vendor optionality inside one editor becomes a governance question rather than a convenience. SpaceX’s ownership places a leading developer interface inside a company that also controls training compute; Cursor’s own closing announcement repeatedly referenced SpaceX’s computing infrastructure, according to TechCrunch. Musk answered on X on August 29, 2026, writing, “I couldn’t care less. Scam Altman and Greg Stockman are utterly untrustworthy,” using a nickname for OpenAI President Greg Brockman, and repeating his claim that they “stole an open source nonprofit,” according to CNBC.

Execution risk is unresolved: Business Insider reported it was unclear which Cursor users or models the shutoff would touch, and OpenAI said it will withhold future models, including Astra. Antitrust review status for the $60 billion transaction was not disclosed, although Forbes reported potential antitrust scrutiny; cross-border regulatory exposure was not disclosed. JV governance terms for the April 2026 SpaceX-Cursor arrangement were not disclosed beyond the exit mechanism: a $60 billion option or $10 billion otherwise. The May 18, 2026 verdict against Musk was advisory, and U.S. District Judge Yvonne Gonzalez Rogers makes the final determination on liability, according to GeekWire. OpenAI’s IPO is expected later in 2026 or in 2027, according to Forbes.

What the cutoff changes

When does OpenAI stop supplying models to Cursor? OpenAI proposed November 12, 2026 in its August 28, 2026 blog post. That is 76 days of notice: August 29-31 (3) + September (30) + October (31) + November 1-12 (12) = 76 days.

Why did OpenAI end the Cursor partnership? OpenAI said it could not be confident SpaceX would use its technology within its terms of service, citing its experience with Elon Musk’s companies violating contracts, and invoked a limited post-change-of-control cancellation window.

What did SpaceX pay for Cursor, and when? SpaceX, listed as Space Exploration Technologies Corp (SPCX), signed a $60 billion all-stock merger agreement with Anysphere on June 16, 2026 and completed it on August 14, 2026, days after its June 12, 2026 Nasdaq IPO raised $75 billion.

Will Cursor lose AI models on November 12, 2026? Not entirely: Anthropic said it will increase compute for Claude in Cursor, and the editor also carries Google and xAI models. Whether migration finishes before the cutoff is not disclosed ( limitation).

What happened to Musk’s lawsuit against OpenAI? A jury cleared OpenAI, Altman and Brockman on May 18, 2026, finding Musk filed too late, and his lawyer vowed an appeal. Fortune and Reuters reported $150 billion in damages sought; CNBC reported the ask as up to $180 billion in “ill-gotten gains” (CONFLICT, both figures reported).

OpenAI gave Cursor 76 days, from August 28, 2026 to November 12, 2026, to lose access to models sitting inside a tool SpaceX paid $60 billion to own. The verified risk is execution: Business Insider reported the affected user and model set was unclear, and Anthropic’s compute pledge rests on one co-founder’s post with no disclosed capacity number. The pattern suggests model access has become contractual leverage in the AI platform war, and November 12, 2026 is a public test of how fast a developer tool can switch suppliers.

Frequently Asked Questions

What does OpenAI do?

OpenAI is an AI research and deployment company that creates advanced models such as GPT-5.6 and Astra. It licenses these models to platforms like Cursor for coding assistance, while also setting safety and compliance terms. The company’s recent decision to end its Cursor agreement reflects its broader emphasis on contractual governance and model distribution control.

Why did OpenAI end its Cursor partnership?

OpenAI cited its inability to be confident that SpaceX, Cursor’s new owner after the $60 billion acquisition, would use its technology within OpenAI’s terms of service. The company pointed to experience with Elon Musk’s companies violating contracts, and exercised a limited cancellation window following the change of control on August 14, 2026.

When does OpenAI stop supplying models to Cursor?

OpenAI proposed a shutoff date of November 12, 2026 in an August 28, 2026 blog post. That gives Cursor about 76 days of notice. OpenAI also said it will not deliver future models, including the upcoming Astra model, to the AI coding tool. The date is 76 days after the announcement.

What did SpaceX pay for Cursor?

SpaceX, under Space Exploration Technologies Corp, completed a $60 billion all-stock acquisition of Anysphere, Cursor’s parent company, on August 14, 2026. The deal came after SpaceX’s June 12, 2026 Nasdaq IPO raised $75 billion, and it priced the company at roughly double its November 2025 Series D valuation. The acquisition closed 14 days after the merger agreement.

What happens to Cursor users after the OpenAI cutoff?

Cursor users will lose access to OpenAI models like GPT-5.6 Luna, Sol and Terra on November 12, 2026. However, Anthropic said it would increase compute for Claude in Cursor, and the editor also carries Google and xAI models. Whether migration completes before the cutoff remains unclear. This presents a clear risk for users reliant on OpenAI.