What platforms does cmux support?

cmux is macOS-only. It's built natively in Swift and AppKit on top of libghostty, so there's no Windows or Linux build.

Does cmux require Ghostty to be installed?

No, cmux is its own app built on the Ghostty terminal engine (libghostty). It does read your existing `~/.config/ghostty/config` for themes and fonts if you have one.

What license is cmux released under?

The README states cmux is open source and GPL-licensed, though the repository metadata doesn't specify an exact license identifier.

Can cmux resume a detached agent session after quitting or a crash?

Yes, for agents whose hooks save a native session ID, cmux can resume them on relaunch. For arbitrary live process state (like tmux or vim), you need to opt into `cmux local-tmux` or `cmux local-zellij` for live detach/reattach.

Is cmux a replacement for tmux?

Not by default. It restores layout, working directories, and scrollback on its own, but live process detach/reattach across quits requires opting into the bundled local tmux or zellij owner.

cmux: A native macOS terminal with vertical

Q: Which AI coding agents does cmux integrate with?

The README lists hook/resume support for Claude Code, Codex, Grok, OpenCode, Pi, Amp, Cursor CLI, Gemini, Rovo Dev, Copilot, CodeBuddy, Factory, and Qoder, plus a dedicated teammate mode for Claude Code.

cmux is a native macOS terminal built on Ghostty, designed for developers who run multiple AI coding agents (Claude Code, Codex, OpenCode, Gemini, Amp, and others) in parallel and need to know when one of them needs attention. It's aimed at terminal-first developers who want a fast, scriptable workspace instead of an opinionated GUI orchestrator.

Instead of relying on generic macOS notifications that just say "waiting for input," cmux adds a sidebar with vertical tabs showing git branch, PR status, working directory, open ports, and the latest notification text per workspace. Panes light up with a visual ring when an agent needs you, and a notification panel lets you jump straight to the most recent unread item.

Key features

Notification rings and panel – panes and tabs flag visually when an agent is waiting, with a panel to see and jump between all pending notifications
Vertical + horizontal tabs – sidebar shows git branch, linked PR number/status, working directory, listening ports, and latest notification per workspace, with full split support
In-app browser – split a scriptable browser pane next to the terminal; agents can snapshot the accessibility tree, click, fill forms, and run JS against it
SSH workflows – cmux ssh user@remote opens a remote workspace, routes browser panes through the remote network, and supports dragging files into remote sessions
Claude Code Teams support – cmux claude-teams spins up teammate mode as native splits with sidebar metadata, no tmux required
Session restore – on relaunch, cmux restores window/workspace/pane layout, working directories, scrollback, and browser history; supported agents can resume via saved session IDs
CLI and socket API – script workspace creation, pane splitting, keystrokes, and browser automation
Ghostty compatible, GPU-accelerated – reads your existing ~/.config/ghostty/config and renders via libghostty
Native Swift/AppKit app – not Electron, so startup is fast and memory use stays low
Browser import – pulls cookies, history, and sessions from Chrome, Firefox, Arc, and 20+ other browsers so browser panes start authenticated

Ideal use cases

cmux fits developers running several coding agents concurrently across multiple panes or tabs and who lose track of which one needs input. It also suits anyone doing remote development over SSH who wants browser panes and file drag-and-drop to work transparently against the remote host, and teams experimenting with Claude Code's teammate mode without wiring up tmux manually.

It's a good fit if you already use Ghostty or want its config/theme compatibility and GPU-accelerated rendering, and if you'd rather script your own workflow via CLI/socket API than adopt a prescriptive agent-orchestration product.

It is not a fit if you need cross-platform support: cmux is macOS-only (built in Swift/AppKit). It's also not the right tool if you want a fully managed, opinionated agent dashboard rather than terminal primitives you assemble yourself, or if you don't run coding agents at all and just need a general-purpose terminal emulator.

Installation

The simplest path is the signed DMG from the releases page:

Download the latest cmux-macos.dmg from the GitHub releases page.
Open the DMG and drag cmux into Applications.
On first launch, macOS will prompt to confirm opening an app from an identified developer; click Open.

cmux auto-updates afterward via Sparkle, so you only need to download once.

Alternatively, install via Homebrew:

brew tap manaflow-ai/cmux
brew install --cask cmux

To update later:

brew upgrade --cask cmux

A nightly build (built from the latest main commit) is also available as a separate app with its own bundle ID, so it can run alongside the stable release.

After installing, set up agent resume hooks for CLIs already on your PATH:

cmux hooks setup
cmux hooks setup codex
cmux hooks setup --agent opencode

cmux hooks setup detects and installs hooks for supported agents (Claude Code, Codex, Grok, OpenCode, Pi, Amp, Cursor CLI, Gemini, Rovo Dev, Copilot, CodeBuddy, Factory, Qoder) and prints a summary for any it skips.