What Is Microsoft eXecution Container (MXC) and How Copilot Sandboxes Tool Execution
MXC is Microsoft's MIT-licensed SDK for running untrusted code, including model output, plugins and tools, under one deny-by-default policy that it maps to Seatbelt on macOS, bubblewrap on Linux and ProcessContainer on Windows. Here is what MXC SDK 1.0.1 and schema 1.0.0 actually define, how Copilot CLI hands it a policy per process, and what stays outside the box.