cmux

Also known as: manaflow cmux, agent terminal, parallel agent terminal

An open-source macOS terminal built for running multiple AI coding agents at the same time. It wraps Ghostty's rendering engine in a native Swift app and adds per-agent notifications, context-aware tabs, and an embedded scriptable browser.

When you run three Claude Code sessions, two Codex agents, and an Aider process in a standard terminal, the setup immediately breaks down. Tab titles blur together, notifications are generic, and you have no idea which agent needs your attention without clicking into each pane. cmux is an open-source macOS terminal from Manaflow AI, built on top of libghostty (the rendering library that powers the Ghostty terminal emulator), that treats AI agents as first-class citizens of the UI.

The two headline features are a vertical tab sidebar and a notification ring system. The sidebar shows each workspace's git branch, pull request status, working directory, open ports, and most recent notification at a glance. The notification ring visually flags which agent is waiting for input, so you can manage four or five parallel sessions without context-switching constantly. cmux also ships an embedded browser pane with a scripting API, so an agent can verify a fix in a live preview without leaving the terminal.

cmux launched in February 2026, reached the top of Hacker News on launch day, and climbed to more than 27,000 GitHub stars by October 2026. It reads your existing Ghostty config, so fonts, colors, and keybindings carry over. It works with Claude Code, Codex, OpenCode, Gemini CLI, Aider, Kiro, and any other CLI-based coding tool. It is macOS-only for now, though a community Linux fork exists.

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