Spot when AI coding agents need input in a native macOS terminal
Running multiple AI coding agents at once can make it hard to track which task is waiting for your input. cmux is a native macOS app that combines a terminal with a browser and notification system. When an agent stops, its window glows blue, and the sidebar shows which branch and task are active, helping you keep your workflow moving between agents.
Notification system for waiting agents
When an agent waits for user input, a blue ring appears on the panel and the sidebar tab is highlighted. The sidebar displays the git branch, connected PR status, working directory, and latest notification text for each workspace. Pressing Cmd+Shift+U jumps to the most recent unread notification, so you can immediately see which task is pending even across multiple split screens. These notifications are triggered automatically via standard terminal escape sequences (OSC 9/99/777) or by connecting the cmux notify CLI to agent hooks.
Built-in browser controlled by agents
cmux allows you to split a real browser panel next to the terminal, and this browser supports a scriptable API. Agents can manipulate web pages directly by taking DOM snapshots, clicking elements, and executing JavaScript. This allows agents like Claude Code to verify changes on a development server directly within cmux. You can also start in an authenticated state by importing cookies and sessions from over 20 browsers, including Chrome, Firefox, and Arc.
Session restoration and remote work support
The current session is saved even if you quit the app, restoring window layout, working directories, and terminal scrollback upon relaunch. Supported agents (such as Claude Code, Codex, and OpenCode) can resume work based on the saved session ID. You can also create workspaces on remote machines and connect to remote tmux sessions to control agents locally using the cmux ssh command. In remote sessions, you can upload images via scp by dragging and dropping them.
Native macOS performance and Ghostty compatibility
cmux is a native macOS app written in Swift and AppKit, offering fast startup and low memory usage unlike Electron-based apps. Terminal rendering uses libghostty, and it reads the existing ~/.config/ghostty/config file to apply theme, font, and color settings as-is. All operations are programmable via CLI and Unix socket API, allowing you to script workspace creation, panel splitting, key input transmission, and browser automation.
Things to check before using
cmux is currently macOS-only, and the iOS app is available in beta via TestFlight. The license is GPL-3.0-or-later, but the cmux server software (such as cloud workers) uses the Business Source License 1.1, requiring a commercial license for production use. Session restoration restores app-owned state (layout, URLs, etc.) but does not checkpoint arbitrary live process states, so you must use cmux local-tmux if processes need to survive after cmux exits. Agent session restoration only works if the agent CLI is in the PATH and hooks are installed.