Relay

Relay is an open-source Model Context Protocol (MCP) server that acts as a message bus between Claude Desktop and Claude Code, enabling seamless, user-controlled transfer of files, code, data, and instructions between both environments without manual copy/paste. It does not interpret or modify the data, instead serving purely as a transport layer—users fetch or send messages on demand, and receive system notifications when something arrives. Relay is ideal for developers and power users working with Anthropic's Claude tools who need efficient, explicit, and context-preserving communication across multiple AI-powered environments. Its architecture prioritizes clear boundaries, minimalism, and extensibility, supporting multiple sessions and offering cross-platform notification support.