You'd reach for this when you need Claude to actually run code instead of just suggesting it. It spins up isolated cloud containers that execute Python, JavaScript, Bash, or Go snippets on demand, keeping the execution environment separate from your local machine. Useful for prototyping scripts, testing code samples in conversation, or running computational tasks without setting up your own sandboxed environment. The isolation means you can experiment freely without worrying about side effects on your system. Think of it as giving Claude a scratch pad where it can test ideas by actually running them rather than simulating output.