SSH

cmux ssh creates a workspace for a remote machine. Browser panes route through the remote network, files drag-and-drop via scp, coding agents send notifications to your local sidebar, and sessions reconnect on drops.

Usage

cmux ssh user@remote
cmux ssh user@remote --name "dev server"
cmux ssh user@remote -p 2222
cmux ssh user@remote -i ~/.ssh/id_ed25519

cmux ssh reads your ~/.ssh/config for host aliases, identity files, and proxy settings. All flags mirror their ssh equivalents.

Flags

Flag	Description
`--name`	Set the workspace title
`-p, --port`	SSH port (default 22)
`-i, --identity`	Path to identity file
`-o, --ssh-option`	Pass arbitrary SSH options (e.g. -o StrictHostKeyChecking=no)
`--no-focus`	Create the workspace without switching to it

Browser panes

Browser panes in a remote workspace route all HTTP and WebSocket traffic through the remote machine's network. Type localhost:3000 and you're looking at the dev server running on the remote box. No -L flags, no manual port forwarding. Each remote workspace gets an isolated cookie store so sessions are scoped per-connection.

Drag and drop

Drag an image or file into a remote terminal and cmux uploads it via scp through the existing SSH connection. cmux detects the foreground SSH process by TTY and routes the upload through ControlMaster multiplexing.

Notifications

Processes on the remote machine can run cmux commands that execute on your local instance. When a coding agent calls cmux notify on the remote box, the notification appears in your local sidebar. The blue ring lights up on the workspace tab. Cmd+Shift+U jumps to it. Notification spam from flaky connections is suppressed with a per-host cooldown.

Coding agents over SSH

cmux claude-teams and cmux omo both work inside SSH sessions. The Go relay daemon on the remote host handles the same tmux-compat translation that the local Swift CLI does. Teammate agents spawn as native cmux splits on your local machine while computation runs on the remote box.

# Inside an SSH session:
cmux claude-teams
cmux omo

Reconnect

When the connection drops, cmux reconnects with exponential backoff (3s, 6s, 12s, up to 60s). The remote session persists and cmux reattaches on reconnect, resizing with smallest-screen-wins semantics. Default keepalive options (ServerAliveInterval=20, ServerAliveCountMax=2) are injected unless your config already sets them.

Relay daemon

On first connect, cmux probes the remote host (uname -s, uname -m) and uploads a versioned cmuxd-remote binary. The binary speaks JSON-RPC over stdio and handles three things:

Feature	How
Browser traffic proxying	SOCKS5 and HTTP CONNECT over the daemon's stdio channel
CLI relay	Reverse TCP tunnel with HMAC-SHA256 auth so remote processes can call cmux commands locally
Session management	Persists sessions across reconnects, coordinates PTY resize across multiple attachments

The daemon binary is stored at ~/.cmux/bin/cmuxd-remote/<version>/<os>-<arch>/cmuxd-remote on the remote host and verified against a SHA-256 manifest embedded in the app.