We've added URL source blocks for images and PDFs in the Messages API. You can now reference images and PDFs directly via URL instead of having to base64-encode them. Learn more in our vision documentation and PDF support documentation.
We've added support for a none option to the tool_choice parameter in the Messages API that prevents Claude from calling any tools. Additionally, you're no longer required to provide any tools when including tool_use and tool_result blocks.
We've launched an OpenAI-compatible API endpoint, allowing you to test Claude models by changing just your API key, base URL, and model name in existing OpenAI integrations. This compatibility layer supports core chat completions functionality. Learn more in our OpenAI SDK compatibility documentation.