cmux-mcp: MCP server for AI agents to control cmux terminals

[daegweon]

Hi! I built cmux-mcp — a Model Context Protocol server that lets AI agents (Claude Code, Claude Desktop, etc.) control cmux terminals.

What it does

Three MCP tools:

• write_to_terminal — Send commands to the active cmux terminal
• read_terminal_output — Read last N lines of terminal output
• send_control_character — Send Ctrl+C, Escape, etc.

Why cmux CLI instead of AppleScript

Forked from iterm-mcp but completely rewritten to use cmux native CLI (cmux send, cmux read-screen, cmux send-key) via Unix socket:

• Works in background — no focus stealing
• Uses stable cmux read-screen API instead of Ghostty debug-only actions
• Resilient to app initialization timing (avoids TabManager issues like SessionEnd/SessionStart hook error: "TabManager not available" when Claude Code is launched via cmux tab #1715)
• Supports --surface targeting for precise pane control

Quick Start

git clone https://github.com/daegweon/cmux-mcp.git
cd cmux-mcp && npm install && npm run build

Add to ~/.claude/settings.json:

{
  "mcpServers": {
    "cmux-mcp": {
      "command": "node",
      "args": ["/path/to/cmux-mcp/build/index.js"]
    }
  }
}

Feedback and contributions welcome!