Y Combinator has made its internal multiplayer agent harness, QM, available under an open-source MIT license. This tool allows employees to work in isolated environments within Slack and the web, while also providing a sandboxed space for each team. QM is compatible with various AI models, including Pi, OpenCode, Codex, and Claude Code, which helps to reduce vendor lock-in. The release of QM is significant because it enables developers to create and customize their own isolated workspaces and deployment environments.