cmux: The Native macOS Terminal Redefined with AI Coding Assistants in Mind

For developers who live in the terminal, the launch of cmux, a native macOS terminal application, marks a significant step forward in productivity and efficiency. Designed specifically for those who manage multiple AI coding sessions, cmux introduces a suite of innovative features that streamline workflow and enhance the coding experience.

Enhanced Notifications and Vertical Tabs

One of the standout features of cmux is its advanced notification system. Unlike traditional terminals, cmux uses blue rings and illuminated tabs to alert users when AI agents require attention. This is particularly useful for developers running multiple sessions of AI coding assistants like Claude Code and Codex. The notification panel consolidates all pending alerts, allowing developers to quickly jump to the most recent unread notification with a simple keyboard shortcut (Cmd+Shift+U).

In-App Browser and Scriptable API

Another game-changing feature is the in-app browser, which can be split alongside your terminal panes. This browser is not just a simple web viewer; it’s a powerful tool with a scriptable API. Developers can use it to interact with their dev servers directly, leveraging AI assistants like Claude Code to automate tasks such as form filling, element clicking, and JavaScript evaluation. The browser’s accessibility tree can be snapped, and element references can be retrieved, making it a versatile addition to the terminal.

Customizable and Scriptable

cmux is built with customization and automation in mind. The application reads your existing ~/.config/ghostty/config for themes, fonts, and colors, ensuring a seamless transition from Ghostty. The CLI and socket API allow for extensive scripting capabilities, enabling users to create workspaces, split panes, send keystrokes, and automate browser actions. This level of control is invaluable for developers who need to tailor their environment to specific workflows.

Native Performance and GPU Acceleration

Built with Swift and AppKit, cmux offers a native macOS experience that is both fast and efficient. Unlike Electron or Tauri-based applications, which can be resource-heavy, cmux boasts a fast startup time and low memory usage. The app is GPU-accelerated, ensuring smooth rendering and a responsive user interface. This native approach also means that cmux integrates seamlessly with macOS, providing a consistent and polished user experience.

Installation and Usage

Installing cmux is straightforward. You can download the DMG file and drag cmux to your Applications folder, or use Homebrew with the following commands:

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

To update cmux, simply run:

brew upgrade --cask cmux

Upon first launch, macOS may prompt you to confirm opening an app from an identified developer. Click Open to proceed.

Why cmux?

The developer behind cmux, who runs numerous AI coding sessions in parallel, created the application to address specific pain points in their workflow. Traditional terminals and coding orchestrators often fall short in terms of performance and flexibility. cmux fills this gap by offering a native, scriptable, and highly customizable terminal that enhances the developer’s interaction with AI coding assistants.

With its innovative features, cmux is not just a terminal; it’s a comprehensive development environment designed to boost productivity and simplify the management of complex coding projects. Whether you’re a seasoned developer or a newcomer to AI-assisted coding, cmux is a tool worth exploring.