AI coding tool Windsurf announced that its platform has relaunched the Claude Sonnet4 model from Anthropic, granting paying users direct access. This news marks Windsurf's successful restoration of support for this cutting-edge AI model after a period of collaboration challenges with Anthropic.
Claude Sonnet4 Returns to Windsurf, Features Fully Opened
According to the latest updates on X, Windsurf officially resumed support for Claude Sonnet4 starting in July 2025, offering Pro users 250 calls per month, with a billing model of 2 times credit consumption. This move ended the previous issue of missing the Claude4 model due to Anthropic's restrictions on direct access. Users can now use Claude Sonnet4 through Windsurf's AI-native IDE to perform efficient code completion, complex refactoring, and context understanding tasks.
Claude Sonnet4 is renowned for its exceptional code generation capabilities and precise instruction following, particularly excelling in programming benchmark tests such as SWE-bench (72.7%). By reintegrating this model, Windsurf further strengthens its competitiveness in the AI coding tool market.
Background: A Turbulent Journey from Restrictions to Recovery
In May this year, when Anthropic released the Claude4 series models (including Sonnet4 and Opus4), it explicitly restricted Windsurf's direct access, requiring users to call them via their own key (BYOK) method, sparking widespread discussions in the developer community. AIbase analysis suggests that this restriction may be related to rumors of OpenAI acquiring Windsurf for $3 billion, with Anthropic possibly taking a conservative approach due to competitive concerns.
To address this challenge, Windsurf quickly introduced the BYOK feature and optimized support for other models, such as Gemini2.5Pro, to compensate for the lack of Claude4. However, community feedback indicated that the BYOK solution was complicated and costly, leading some users to switch to competing platforms like Cursor that support Claude4.
The relaunch of Claude Sonnet4 indicates improved collaboration between Windsurf and Anthropic. Users on X stated that the combination of Windsurf's interface and AI-native features with the powerful performance of Claude Sonnet4 has made it a preferred tool for improving coding efficiency again.
Feature Highlights and User Experience
Applications of Claude Sonnet4 on Windsurf include:
- Code Generation and Refactoring: Supports multi-file complex refactoring, generates high-quality code snippets, and reduces the need for manual modifications.
- Context Understanding: Utilizes an ultra-large context window of 200K tokens to accurately process large codebases, reducing navigation errors.
- Real-Time Suggestions: Provides context-aware code completion and automated workflows through Windsurf's "Cascade" feature.
User feedback shows that Claude Sonnet4 performs better than Gemini2.5Pro in handling complex coding tasks, especially in scenarios requiring multi-step reasoning. However, the 2 times credit billing model may impose cost pressure on frequent users; some developers have suggested that Windsurf optimize its pricing strategy to enhance appeal.
The relaunch of Claude Sonnet4 by Windsurf is not only a technical breakthrough but also reflects the increasingly fierce competition in the AI coding tool market. In the ongoing competition among OpenAI, Microsoft (GitHub Copilot), and Anthropic, Windsurf, as a multi-model support platform, needs to balance user experience with cost control.
Looking ahead, Windsurf may further optimize the integration experience of Claude Sonnet4 or consolidate its market position by supporting more cutting-edge models, such as potential Claude4.5 or new models from OpenAI. At the same time, whether Anthropic will further open up direct access to Claude Opus4 remains a focus of attention among developers.