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cmux Review: The Native macOS Terminal Built for AI Coding Agents

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Discover cmux, a free open-source native macOS terminal optimized for AI coding agents with vertical tabs, split panes, and a scriptable browser.

cmux: Native macOS Terminal for AI Coding Agents

cmux is a free, open-source native macOS terminal designed specifically for managing multiple parallel AI coding agents. Built on the GPU-accelerated libghostty rendering engine, it integrates split panes, vertical workspace tabs, and a built-in scriptable browser to streamline multi-agent workflows.

Whether you are running tools like Claude Code, Codex, Aider, Kiro, or the Gemini CLI, cmux helps coordinate parallel terminal sessions without the resource overhead of Electron-based apps.

Key Capabilities

  • Native macOS Integration: Built using Swift and AppKit with GPU-accelerated rendering powered by libghostty.
  • Vertical Workspace Tabs: A dedicated sidebar displays essential repository context, including current Git branch, pull request (PR) status, active ports, and terminal notifications per workspace.
  • Built-in Scriptable Browser: A companion browser panel allows developers to preview web applications and automate interactions directly from the command line.
  • Notification Rings: Visual indicators highlight terminal panes that require user attention or input, supporting standard protocols like OSC 9/99/777 and the custom cmux notify CLI.
  • CLI & Socket API: A full socket API and command-line interface enable deep automation and custom hook integration for agent workflows.

Standout Features

Vertical Tabs

Unlike standard horizontal tabs, cmux features a sidebar navigation layout. Each workspace tab displays live context, letting you track git branch details, active local ports, and the latest status notifications for each of your running projects at a glance.

Notification Rings

Running multiple background agents can make it difficult to spot when one has paused for input. cmux solves this by flashing visual "notification rings" around panes. You can trigger these alerts manually or programmatically using the CLI.

Built-in Browser

Avoid tab-switching fatigue with an integrated browser surface sitting right next to your terminal. Through the command line, you can open URLs, capture snapshots, click elements, and populate form fields programmatically.

Resource-Efficient GPU Rendering

By using libghostty instead of a web-view wrapper, cmux provides low-latency terminal rendering, optimized battery performance, and a native macOS feel.

Target Use Cases

  • Multi-Agent Workflows: Ideal for developers running multiple agents simultaneously across different repositories.
  • macOS Power Users: Built for developers who prefer native AppKit applications and CLI-centric setups.
  • Parallel Coding Sessions: Clean environment splitting for testing multiple implementations or comparing agent performance.

Pricing & Licensing

Alternatives to Consider

If you are looking for tools with similar multi-agent coordination capabilities, you may also want to explore:

  • NTM (Named Tmux Manager): A free, open-source terminal utility that turns standard tmux sessions into a multi-agent control center with broadcast prompts, TUI command palettes, and persistent sessions.
  • Google AntiGravity: Google's agentic development ecosystem, which features a standalone desktop surface, CLI, custom SDK, and IDE extensions.
  • Aider: A popular open-source command-line tool that lets you pair-program with LLMs directly within your git repository.