Author: Xin Xin
OpenAI's major acquisition is stimulating the nerves of the entire AI coding tool market.
In mid-April this year, it was revealed that OpenAI would acquire the AI programming platform Windsurf (formerly known as Codeium) for about $3 billion. (For details, scan the QR code in the image below to listen to the Geek Park podcast👇)
During the transaction process, Windsurf was dealt a blow by another AI giant, Anthropic: access to the Claude series models was restricted, and even on the day Claude 4 was released, Windsurf did not receive access eligibility.
On June 3, Windsurf CEO Varun Mohan publicly complained on X that Anthropic decided to cut off almost all access to the Claude 3.x models, stating they "only received less than five days of notice."
An AI coding company, before even receiving the acquisition money, suddenly became a "sandwich cookie" in the game between AI giants, quickly moving towards factionalization.
Does Anthropic's "cut-off" of Windsurf mean that AI coding has become a battleground for AI giants? As the hottest entrepreneurial track, how should AI coding entrepreneurs choose their next steps?
01 Windsurf, from neutral to taking sides
Windsurf was not originally an AI programming company but a GPU virtualization startup founded in 2021, which only transitioned to becoming an "AI programming IDE" in 2022, leveraging large models to turn natural language prompts into code, understand large codebases, and emphasize the experience of "freely switching models."
In other words, initially, the platform remained neutral, and users chose models themselves, using whichever they liked, regardless of whether users thought Claude was strong, GPT was stable, Gemini was new, or whether they wanted to use Deepseek, Grok, etc., Windsurf supported them all.
Its core product is an IDE that supports natural language programming, not only supporting multiple models but also featuring its self-developed Cascade Agent, Supercomplete completion system, and real-time preview functionality. From a VS Code plugin to an independent platform, Windsurf can be seen as a model of "AI-native coding."
Windsurf's AI coding agent Cascade | Image source: Windsurf
This "Vibe coding" model has attracted a large number of programmers and startups, even penetrating the enterprise user market. By early 2025, Windsurf claimed its annual recurring revenue (ARR) had surpassed $100 million, with daily active users reaching several hundred thousand. Even though its data lags behind more popular tools like Cursor and GitHub Copilot, Windsurf remains one of the strong players in the AI programming field.
Originally, neutrality was neutrality, but after being acquired by OpenAI, its "model choice" label became awkward. In the eyes of some developers, this may mean Windsurf has fallen from being a model neutral entity to becoming a "exclusive entry for GPT," with its independence becoming uncertain.
Windsurf originally had the option to choose from various models, including Claude | Image source: Windsurf
OpenAI has not made a clear statement on whether it will limit model choices, but its competitor Anthropic's response has already hinted: completely cutting off Windsurf's first-party access to the Claude 3.x series, and native support will no longer be provided for Claude 4 upon its launch. Users who still wish to use Claude can only access it through their API keys, which is a cumbersome process, incurs higher costs, and has worse stability.
From user reactions at Windsurf, some developers have already expressed anger and frustration. Some developers have directly switched tools, such as moving to Cursor, just to continue using Claude 4.
Windsurf CEO Varun Mohan publicly complained on X, "Due to Anthropic's short notification time, we may encounter some availability issues with the Claude 3.x models in the short term." "We have clearly expressed to Anthropic that this is not what we wanted — our intention was to pay them for full capacity. We are disappointed with this decision and the short notice."
He also mentioned other vendors, stating that to ensure sufficient short-term resource supply, he increased the capacity of other inference service providers, "Gemini 2.5 Pro (currently of very high quality on Windsurf and enjoying a new 0.75x promotional price), GPT 4.1, and more models have not been affected. We look forward to continuing to collaborate with all model providers."
Windsurf CEO complains about Anthropic cutting off Claude models | Image source: X
In an official statement released by the company, Windsurf specifically mentioned, "We are concerned that Anthropic's actions will harm the interests of the entire industry, not just Windsurf's interests."
From being a beneficiary of large models to being forced to choose sides, Windsurf may not have anticipated that Anthropic's "cut-off" action would come so quickly and directly.
02 The "Agent War" in AI Coding
Anthropic's action to cut off Windsurf's model access is, of course, seen by many as a direct attack on OpenAI.
Various players in the AI programming field, whether it's Cursor from Anysphere, Devin from Cognition, or GitHub Copilot, can all use Claude. This also shows that it's not that Claude is unwilling to open up; it's just that it doesn't want to open up to its "greatest rival."
Regarding the cut-off incident, Anthropic's public relations response is to prioritize resource allocation to "sustainable" partners, of course, without directly mentioning OpenAI, but it is widely interpreted in the industry as a statement of allegiance. Anthropic likely does not want user data from using Claude on the Windsurf platform to be directly sent to OpenAI.
When Anthropic founders Dario Amodei and Daniela Amodei left OpenAI, their public statement was dissatisfaction with OpenAI's development direction; they had previously been responsible for OpenAI's safety research.
Moreover, Anthropic has billions of dollars in investments from Google and Amazon; while OpenAI is deeply tied to Microsoft and controls GitHub Copilot. All parties are trying to compete for the developer entry by supporting tools and controlling models.
It is also worth mentioning that as the programming capabilities of large models improve, Vibe Coding is becoming increasingly popular. Anthropic recently not only wants to distribute its large models to various AI wrapper companies but is also seeking to "self-operate" more.
Anthropic launches Claude Code | Image source: Anthropic
In the first half of this year, Anthropic has already begun to shift the use cases of the Claude models to its own products — such as the recently released Claude Code in February and the self-owned tools highlighted at the "Code with Claude" conference in May.
After all, Anthropic's current flagship is still the programming capabilities of the Claude models, which is a competitive advantage against other large model vendors.
And Windsurf, now acquired by OpenAI, clearly taking sides, has naturally become the first target to be "blacklisted."
Windsurf's "intimacy" with OpenAI began to become public in April this year. Windsurf CEO Varun Mohan participated in the live broadcast for the launch of the GPT-4.1 model. When OpenAI launched new programming products, he also praised them on social media, saying they "look very cool" and that "those who are blind to this are unaware of the power of exponential curves and do not understand how significant this technology will progress."
Windsurf CEO (left in the image) interacts with OpenAI products and teams | Image source: X
On OpenAI's side, they have already realized that the pure large model service model may not be sustainable, and they have been actively making moves at the application layer, with AI programming becoming one of the key focuses, as this area is a hot "traffic entry" for model distribution competition.
This year, its actions include integrating the AI programming agent "Codex" into ChatGPT Plus, as well as open-sourcing the local programming agent "Codex CLI." Acquiring Windsurf may enhance OpenAI's capabilities in developer tools, especially by bringing Windsurf's established user base into the OpenAI ecosystem while competing for territory, gaining control, and weakening rivals' large model distribution channels.
However, regardless of what OpenAI will do with Windsurf, whether it has considered Anthropic's reaction, when Anthropic's Claude model programming capabilities are still very strong, if users turn to other tools as a result, Windsurf's own interests will undoubtedly be affected.
For the entire industry, if models are tied to platforms, developers may worry that this is a signal of the AI programming market heading towards "platformization and closure."
For instance, some might think that future development tools will be as fragmented as smartphone operating systems — either iOS or Android; either GPT or Claude.
Windsurf being cut off by Anthropic is by no means an accidental business decision, but the first shot in the battle among AI giants.