Composer

Composer is a real-time, multiplayer markdown editor where people and AI agents work side by side on the same document. Teams collaborate in real time while agents connect as true collaborators via the Model Context Protocol (MCP), rather than being bolted on as a separate chat sidebar. Documents are stored in plain markdown format, keeping them portable and accessible in other editors outside Composer. Built-in commenting and suggestion tools support team refinement of shared documents, and a "bring your own agent" (BYOA) model gives flexibility in which AI agent connects to a given document.