Theia AI and Theia IDE support Claude 4 Sonnet and Opus

Exciting news for developers and tool builders: Theia AI and the AI-powered Theia IDE now support the new Claude 4 Sonnet and Claude 4 Opus models right out of the box. These revolutionary models, announced by Anthropic as setting new standards for coding and advanced reasoning, can be used seamlessly without any update—simply add them to the list of Anthropic models (as shown below), and you’re ready to go.

In case you don’t know Theia AI or the AI-powered Theia IDE, visit the Theia AI introduction and the AI Theia IDE overview, or download the AI-powered Theia IDE here.

Add Claude 4 Sonnet and Opus to Theia AI

Theia AI, a framework for building AI-powered tools and IDEs, is designed to be fully extensible. It supports arbitrary LLMs from various providers including OpenAI, Anthropic, HuggingFace, Azure, self-hosted or local LLMs (see Why Theia AI support any LLM).

The AI-powered Theia IDE is built on Theia AI and gives even end users complete control over their AI interactions. Therefore, in the Theia IDE, end users can easily add new models to work with. So let’s add the new Claude 4 models: Claude Sonnet 4 and Claude Opus 4 (see screenshot below)! With a simple setting, both Claude 4 Sonnet and Claude 4 Opus will work fine immediately. The models support all of Anthropic’s latest capabilities including extended thinking, parallel tool use, and enhanced memory features when given access to local files.

Now we are fully set and can use Anthropic’s latest frontier models, Claude 4 Sonnet and Claude 4 Opus, with all agents in the Theia IDE. Claude 4 Opus is particularly exciting as it’s being called “the world’s best coding model” with state-of-the-art performance on complex coding tasks, while Claude 4 Sonnet delivers superior coding and reasoning with enhanced precision.

Let’s test Claude 4 Sonnet with the Theia Coder agent in the Theia IDE to complete a very simple coding task. For demonstration, we use Claude 4 Sonnet to add both new Claude 4 models to the default list of available models in the Theia IDE code base, so that future releases will provide them as options even without users adding them manually to the settings (see also the following video). As you can see, Claude 4 Sonnet excellently navigates the workspace to find the correct place and then suggests precise changes to add the new models to the default list.

Conclusion

Theia AI and the AI-powered Theia IDE continue to push the boundaries of flexibility and openness in AI-powered development environments. With seamless support for Anthropic’s latest Claude 4 models, Sonnet and Opus, developers and tool builders can work with cutting-edge coding and reasoning models without friction.

Thanks to Theia AI’s extensibility, integrating new models is as simple as updating the configuration—whether you’re using Theia IDE or building a custom AI-powered tool. This ensures that both tool providers and end users remain in full control of their AI workflows, adapting quickly to new advancements while maintaining transparency and flexibility.

Claude 4’s advanced capabilities, including extended thinking with tool use, parallel tool execution, and improved memory features, make it particularly well-suited for complex coding tasks and agent workflows. The models’ enhanced instruction following and reduced shortcut behavior ensure more reliable and precise results in development environments.

If you want to explore the full potential of Theia AI or optimize your setup for specific LLMs, now is the perfect time to dive in. Whether you’re looking to enhance your own AI-powered tool, extend Theia IDE, or contribute to the open-source ecosystem, Theia AI provides everything you need to get started.

For more details, check out our blog post: Introducing AI Support in Theia IDE and Introducing Theia AI (the underlying framework for tool builders).

If you are interested in building custom AI-powered Tools, EclipseSource provides consulting and implementation services backed by our extensive experience with successful AI tool projects. We also specialize in web- and cloud-based tools and support for popular platforms like Eclipse Theia and VS Code.

Get in touch with us to learn more.