Cmux MCP Server

A Model Context Protocol server that provides access to the currently active tab of cmux

Local serverstdioPython

What is the Cmux MCP MCP server?

Cmux MCP MCP server is a locally run integration for AI assistants that speak the Model Context Protocol. A Model Context Protocol server that provides access to the currently active tab of cmux.

What you get

Let Claude run commands, read output, manage tabs/panes/workspaces/windows, and send control characters in your cmux terminal -- all through the Model Context Protocol. Works in the background. No focus stealing.

What the assistant can call

Once Cmux MCP is connected, these are the calls the assistant has available:

  • Requirements — The Requirements tool exposed by this server
  • Notifications — The Notifications tool exposed by this server
  • Buffer — The Buffer tool exposed by this server
  • Browser — The Browser tool exposed by this server

Setting it up

Setup follows the usual MCP pattern — install or clone the server, register it in your client's configuration file, restart the client. The configuration blocks on this page cover the common clients.

Configuration and credentials

You will need one environment variable: CMUX_PATH. Keep credentials in your client's env block or a secrets manager rather than in a file you might commit.

  • macOS - cmux.app installed and running - Node.js 18+ - cmux socket control mode set to Automation or Open Access (Settings > Automation > Socket Control Mode)

Choosing this one

Among the browser automation options, the useful question is rarely "what can it do" but "what does it cost you to run" — permissions, credentials, and how much of your context its toolset consumes. Cmux MCP's toolset — Requirements, Notifications, Buffer and 1 more — is a fair guide to whether it matches your workflow. It is maintained by daegweon; worth a glance at recent repository activity before you build anything load-bearing on it.

SyncDev reviews every entry in this directory against the project's own documentation before publishing, and revisits them as servers change.

Before you rely on it

  • It runs with your machine's permissions. That is convenient and also the reason to think about what you point it at before you approve a tool call.
  • MCP clients confirm each tool call by default. Leave that on until you have watched what the cmux mcp mcp server does with a few real requests.

Available tools

ToolWhat it does
RequirementsThe Requirements tool exposed by this server.
NotificationsThe Notifications tool exposed by this server.
BufferThe Buffer tool exposed by this server.
BrowserThe Browser tool exposed by this server.

How to install the Cmux MCP MCP server

{
  "mcpServers": {
    "cmux-mcp": {
      "command": "npx",
      "args": ["-y", "cmux-mcp"]
    }
  }
}

Configuration as documented by the project. Restart the client after saving.

Configuration

  • macOS - cmux.app installed and running - Node.js 18+ - cmux socket control mode set to Automation or Open Access (Settings > Automation > Socket Control Mode)
VariableDescriptionRequired
CMUX_PATHFilesystem location the server is allowed to use.Optional

Example prompts to try

  • Use Cmux MCP to Requirements.
  • Use Cmux MCP to Notifications.
  • Use Cmux MCP to Buffer.

Frequently asked questions

It connects Cmux MCP to MCP-compatible AI assistants such as Claude and Cursor, exposing 4 tools (Requirements, Notifications, Buffer, and more) that the assistant can call on your behalf. Instead of copying data back and forth by hand, the assistant works with Cmux MCP directly.