cmux

A macOS-native AI coding terminal built on Ghostty, featuring vertical tabs, notification system, and embedded browser for multi-agent workflows.

cmux is a macOS-native terminal app designed for multi-tasking AI coding agent workflows, built on Ghostty's libghostty rendering engine (Swift + AppKit, not Electron). Developed by manaflow-ai, current version v0.63.2, licensed under GPL-3.0-or-later.

Core Capabilities#

Notification System#

Notification Rings: Blue halo on panes when agents need attention, sidebar tabs light up
Notification Panel: Centralized view of pending notifications, Cmd+Shift+U jumps to latest unread
Triggers: Auto-detects OSC 9/99/777 escape sequences, or via cmux notify CLI and Claude Code hooks

Vertical Tabs & Sidebar#

Sidebar shows: git branch, PR status/number, working directory, listening ports, latest notification text
Horizontal/vertical split panes, multi-workspace support (Workspaces 1-8)

Embedded Browser#

Split-pane browser, API ported from agent-browser
Accessibility tree snapshots, element references, click, form fill, JS execution
WebAuthn / Passkey / FIDO2 support
Import cookies, history, sessions from 20+ browsers (Chrome, Firefox, Arc, etc.)

SSH Remote Development#

cmux ssh user@remote creates remote machine workspaces
Browser pane routes through remote network, localhost directly accessible
Drag-and-drop image upload via scp to remote sessions

Claude Code Teams#

cmux claude-teams one-command launch for Claude Code teammate mode
Teammates start as native split panes with sidebar metadata and notifications, no tmux needed

Scripting & Automation#

CLI and socket API: create workspaces, split panes, send keystrokes, control browser
Custom commands: define project-specific actions via cmux.json, launch from command palette
GPU-accelerated rendering (based on libghostty)

Ghostty Compatibility#

Auto-reads themes, fonts, colors, and keybindings from ~/.config/ghostty/config

Architecture#

Rendering: libghostty as library (not fork), bridged to Swift via ghostty.h / cmux-Bridging-Header.h
UI: Swift + AppKit native macOS app, Xcode project (GhosttyTabs.xcodeproj)
Browser Engine: Embedded WebKit (macOS native), API ported from agent-browser
Notifications: OSC 9/99/777 escape sequence detection + CLI hook dual channel
Automation: CLI + socket API dual-channel control
SSH Remote: daemon/remote directory for remote proxy and browser network routing
Distribution: Sparkle framework, nightly and stable independent channels (nightly has separate bundle ID)
Package Management: Homebrew tap (homebrew-cmux submodule)
CI/CD: GitHub Actions automated build and signing
Website: Next.js deployed on Vercel

Installation#

DMG (recommended): Download .dmg from GitHub Releases, drag to Applications, auto-updates via Sparkle.

Homebrew:

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

Nightly: Standalone app with separate bundle ID, coexists with stable version.

Keyboard Shortcuts#

Category	Shortcut	Function
Workspace	⌘N	New workspace
	⌘1-8	Switch to workspace 1-8
	⌘B	Toggle sidebar
Split	⌘D	Split right
	⌘⇧D	Split down
Notifications	⌘I	Show notification panel
	⌘⇧U	Jump to latest unread
Browser	⌘⇧L	Open browser in split
Terminal	⌘K	Clear scroll buffer

Ecosystem Compatibility#

Compatible with all major terminal AI agents: Claude Code, Codex, OpenCode, Gemini CLI, Kiro, Aider, Goose, Amp, Cline, Cursor Agent, etc.

Known Limitations#

macOS only; Linux/Windows support unconfirmed
Does not restore active process state inside terminals (e.g., tmux/vim sessions), noted as "not resumed after restart yet"
iOS app, Cloud VMs, and Voice mode mentioned in Founder's Edition but no publicly verifiable release or timeline
socket API protocol documentation and full cmux.json schema not detailed in public materials