cmux

Controls the cmux macOS terminal app (Ghostty-based, AI-agent-aware) via its CLI socket API. Use this skill to: open browser preview panes when a dev server starts or an HTML file is created; spin up named workspaces for parallel subagents; show live sidebar progress/status during long tasks; open utility splits on demand (logs, URLs, terminals) in any direction. Also handles `/cmux demo` — an interactive walkthrough with 3 screens of options that runs personalized live demos. Trigger when: a server starts and needs previewing, an HTML/URL artifact is created, parallel subagents are dispatched, a long task needs visible progress, the user asks to open/show something in a split or tab, or the user invokes `/cmux demo`.