Cmux: purpose-built terminal multiplexer for orchestrating AI coding agents

Source
cmuxterminal-multiplexerai-agentsclaude-codeghosttydeveloper-workflowmulti-agent

Summary

Cmux is a native Mac terminal app built on Ghostty, designed specifically for managing multiple AI coding agents (Claude Code, Codex, etc.) simultaneously. It provides a sidebar with bird’s-eye view of all workspaces, built-in notifications when agents need input, and keyboard shortcuts to jump between sessions - replacing DIY tmux/notification setups.

Key Insight

When running multiple AI coding agents in parallel across different projects, the main bottleneck becomes awareness: knowing which agent finished, which needs input, and what’s happening across all sessions. Cmux solves this with three key features:

  1. Sidebar with vertical tabs - each tab shows git branch, working directory, listening ports, and last notification. At a glance you see the state of every agent.
  2. Built-in notification system - when an agent finishes or needs input: the pane gets a blue ring, the tab lights up, and you get a macOS desktop notification. No custom hooks needed.
  3. Cmd+Shift+U - jumps to the most recent unread notification, which is the critical “what needs my attention next?” shortcut.

Alternatives mentioned: Tmux, Conductor, Zellij - but Cmux was chosen because it’s purpose-built for AI agent orchestration rather than adapted from general terminal multiplexing. Built on Ghostty so it’s fast and native.