cmux Review (2026): The Native macOS Terminal Built for AI Coding Agents

Running three Claude Code instances, a Codex agent, and a Gemini CLI session in parallel tmux panes works, but it's held together with duct tape. You can't tell which agent is waiting for input, which one finished, or which one hit an error without manually checking every pane.

cmux was built to solve exactly this. It's a native macOS terminal that treats AI agent orchestration as a first-class feature: visual notifications when agents need attention, a built-in browser for checking docs mid-session, and GPU-accelerated rendering from Ghostty's engine under the hood.

What Is cmux?

cmux is a free, open-source terminal application for macOS, built on Ghostty's libghostty rendering engine. It launched in February 2026 and quickly gained traction in the AI coding community: 7.7k GitHub stars in its first month (source).

The core idea: your terminal should know you're running AI agents and help you manage them. Vertical tabs, notification rings when agents complete tasks or need input, a built-in browser for reference, and a scriptable API for automation.

Full details on the cmux tool page.

Key Features

Agent Notifications

The killer feature. When you're running multiple agents across tabs, cmux shows visual indicators for each one: green when an agent completes a task, yellow when it's waiting for input, red on errors. You know at a glance which agent needs your attention without switching through every tab.

This sounds small, but when you're running 4-5 agents in parallel, it changes the workflow from "constantly checking panes" to "work on something else and respond when pinged."

Built-in Browser

Open documentation, GitHub PRs, or API references in a split pane without leaving the terminal. When an agent suggests a fix that references a library, you can check the docs right there. It's not a full browser, think of it as a focused reference panel.

Installation

brew install dicklesworthstone/tap/cmux

Or the one-liner:

curl -fsSL https://raw.githubusercontent.com/Dicklesworthstone/cmux/main/install.sh | bash

Add shell integration:

eval "$(cmux shell zsh)"

If you're already using Ghostty, your existing config carries over.

cmux vs tmux

cmux wins on visual feedback and macOS-native experience. tmux wins on cross-platform support, session persistence, and decades of battle-tested stability. For dedicated macOS AI agent workflows, cmux is the better choice. For everything else, tmux remains the standard.

Community Reception

The response has been overwhelmingly positive:

• BetterStack published a detailed guide calling it a tool that "transforms AI agents from opaque tools into transparent collaborators" (source)
• A reviewer wrote "If you're a Mac user running AI coding agents regularly: especially Claude Code: CMUX is worth trying" (source)
• 95%+ positive sentiment on X, with users sharing migration stories from Ghostty + tmux setups

The creator has been transparent about limitations: a January 2026 note acknowledged tmux scrolling/text selection still needs work. That kind of honesty is refreshing.

Pros and Cons

Who Should Use cmux?

Strong fit:

• macOS developers running Claude Code, Codex, or Gemini CLI daily
• Multi-agent workflows (3+ agents in parallel)
• Developers migrating from Ghostty who want agent-aware features
• Anyone who wants visual feedback on agent status

Weaker fit:

• Linux/Windows developers (not available)
• Teams needing robust session persistence (tmux is more reliable)
• Developers who don't run AI agents regularly (overkill)
• SSH-heavy workflows where session restore is critical

FAQ

What is cmux? cmux is a free, open-source native macOS terminal built on Ghostty's rendering engine, designed for running multiple AI coding agents like Claude Code, Codex, and Gemini CLI in parallel with notifications and a built-in browser.

Is cmux free? Yes, cmux is completely free and open-source under the AGPL license with no paid tiers.

How does cmux compare to Ghostty? cmux is built on Ghostty's libghostty engine with the same GPU-accelerated rendering speed, but adds vertical tabs, agent notifications, a built-in browser, and a scriptable CLI that Ghostty does not have.

Is cmux better than tmux for AI agents? For GUI-based multi-agent work on macOS, yes. cmux provides visual notifications, a built-in browser, and native macOS integration that tmux cannot match. tmux wins on cross-platform support and SSH persistence.

Does cmux work with Claude Code? Yes, cmux is specifically designed for AI coding agents. Claude Code, OpenAI Codex, and Gemini CLI all work natively with agent-aware notifications.

The Verdict

cmux is the first terminal that takes multi-agent AI coding seriously. The agent notifications alone justify the switch for anyone running parallel Claude Code or Codex sessions on macOS. Add GPU-accelerated rendering, a built-in browser, and Ghostty config compatibility, and you've got a genuinely useful tool.

It's early: launched a month ago, macOS-only, no session restore. But the 7.7k stars and rapid iteration suggest this is going somewhere. If you're on macOS and running AI agents daily, try it. If you're on Linux, keep watching: cross-platform might come eventually.

Try cmux →

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Comparing terminal tools for AI agents? See our best AI code editors roundup or browse the full AI tools directory.