OpenAI announced over the weekend that it would terminate Cursor's direct access to its models starting in November, citing concerns about Elon Musk's track record of contract violations across his companies. The decision referenced Twitter's breach of a data-licensing agreement following Musk's 2022 acquisition and xAI's use of OpenAI models through distillation earlier this year. With SpaceX's $60 billion acquisition of Cursor now complete, OpenAI stated it cannot trust that the company will comply with its terms of service.

OpenAI explained the move in a statement: "This decision was incredibly tough, as we care deeply about our models being broadly available for developers. 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."

What drew attention was Anthropic's swift response. Tom Brown, Anthropic's co-founder and chief compute officer, posted publicly within hours to declare that Cursor remains a "trusted partner" and that Anthropic will "continue to increase compute to support Claude models in Cursor." This stance stands in sharp contrast to Anthropic's handling of similar situations in the past.

A Pattern of Swift Cutoffs

https://x.com/NotTomBrown/status/2093541294027280657?ref_src=twsrc%5Etfw

Anthropic has demonstrated a willingness to sever relationships quickly when potential conflicts emerge. In May 2025, reports surfaced that OpenAI was negotiating to acquire Windsurf, an AI coding tool, for $3 billion. Within weeks of the announcement, Anthropic revoked Windsurf's access to Claude 3.5 Sonnet and Claude 3.7 Sonnet. Jared Kaplan, an Anthropic co-founder, later remarked at a TechCrunch event that it would be unusual for Anthropic to supply Claude to OpenAI. The OpenAI deal ultimately collapsed, and Google subsequently acquired Windsurf's founders and research team for DeepMind, paying $2.4 billion.

Gergely Orosz, an engineer and author of the Pragmatic Engineer newsletter, highlighted the Windsurf episode in a social media post on Sunday, noting that the company had previously held "trusted partner" status. "They cut them off ruthlessly when RUMORS of OpenAI potentially buying Windsurf surfaced," Orosz wrote. "Now, SpaceX, an Ant(hropic) competitor bought Cursor — it's still a trusted partner?"

Similarly, Anthropic moved against xAI, the AI company Musk founded in 2023 to develop Grok. SpaceX acquired xAI in February in a transaction valuing the company at $250 billion. In January, Kylie Robison reported that Anthropic had blocked xAI staff from accessing Claude through Cursor, with Cursor citing "a new policy anthropic is enforcing for all its major competitors."

The Compute Leverage Factor

The critical difference between SpaceX and the previous cases lies in Anthropic's substantial compute dependency on SpaceX. In May, Anthropic announced it had secured the entire output of SpaceX's Colossus 1 data center near Memphis, Tennessee—over 300 megawatts of capacity and more than 220,000 Nvidia GPUs. This arrangement addressed Anthropic's compute constraints and enabled it to immediately raise usage limits for Claude Pro and Max subscribers.

The financial scale of the arrangement became clear when SpaceX's IPO filing disclosed the terms. Anthropic committed to paying $1.25 billion monthly for compute access spanning Colossus and Colossus II—approximately 325,000 Nvidia GPUs combined—with the contract running through May 2029 and subject to termination provisions. SpaceX indicated the deal would allow it to monetize excess compute capacity while maintaining sufficient resources for its own AI training and inference operations.

This arrangement created an unusual dynamic: Anthropic was simultaneously purchasing billions of dollars in compute from a company that owned one of its direct AI competitors in xAI. Amjad Masad, founder and CEO of Replit, responded to Tom Brown's post on Saturday by drawing a direct line between Anthropic's current support for Cursor and its harsher treatment of Windsurf. "Maybe you changed your ways, but we all remember what you did to Windsurf, which was infinitely nastier," Masad wrote. "More likely answer is that you can't do that here because you need the compute."

Orosz advanced a similar analysis, questioning why Anthropic would publicly commit to expanding Claude capacity for Cursor after SpaceX's acquisition if the company truly viewed SpaceX as a competitor. "Either SpaceX and Grok are not competitors to Anthropic (they are!); or, more likely, SpaceX leasing its Colossus 1 data center is more important to Anthropic than to stop offering Claude to SpaceX," Orosz wrote. "SpaceX basically in this enviable position where one of its biggest competitors depends on its compute infra!"

SpaceX now occupies a position of considerable leverage. It owns both xAI and Cursor, competing directly with Anthropic in foundation models through Grok and in AI coding tools through Cursor, while simultaneously collecting billions in monthly payments from Anthropic for the compute infrastructure supporting Claude. Unlike Windsurf and xAI at the time Anthropic moved against them, SpaceX possesses a concrete mechanism to influence any future decision about Claude access.

Source: The New Stack