Mux0 – Open-source macOS terminal with workspace tabs and agent hooks

Mux0 is a macOS terminal I built because I spend most of my day running coding agents (Claude Code, OpenCode, Codex) in tabs, and existing terminals don't know they're there. You end up with a wall of identical tabs and have to click through them to find which agent is waiting on input.

It's organized around workspaces with tabs and splits. Each workspace shows git branch and PR status in the sidebar. There's a small wrapper around the agent CLIs that pipes status events (running / idle / needs input) over a Unix socket, so the sidebar and tab icons reflect agent state — you can tell at a glance which one is blocked on you without switching tabs.

Rendering is libghostty, the Ghostty engine exposed as a C library. The chrome is Swift/AppKit and the sidebar/settings are SwiftUI. Terminal surfaces aren't serialized — only the tree shape and IDs — so restarts are fast and there's no fragile session state to corrupt.

It's early. Working: tabs, splits with drag dividers and keyboard nav, themes (reuses Ghostty's theme files), per-workspace default command, agent status, auto-update via Sparkle, English and Simplified Chinese.