Code execution tool SDKs: Python, TypeScript, Go, Java, Ruby, PHP, C#

Python, TypeScript, Go, Java, Ruby, PHP, and C# SDKs now include support for code_execution_20260120, the code execution tool version that adds REPL state persistence and is the minimum version for programmatic tool calling. Set tool's type to code_execution_20260120; no beta header required. Available on Claude Fable 5, Mythos 5, Opus 4.5+, and Sonnet 4.5+.