cmux

cmux is a Ghostty-based multiplexer, and AgentBox has the deepest integration with it:

• left sidebar shows boxes and agents status
• notifications for boxes that are pending input
• Ctrl+a t shortcut launch a new persistent shell inside the current box
• (optonal) with agentbox install cmux add a right sidebar with list of running boxes. To enable cmux -> Settings -> Beta features -> Dock

Box state in the left sidebar

While you're attached to a box inside cmux, AgentBox reflects the agent's live activity on the box's workspace — its colour and description in the left sidebar — so you can see what every box is doing at a glance:

The workspace's original colour and description are restored when you detach. This is controlled by attach.cmuxStatus (default true); set it to false to turn it off. It's a no-op outside cmux.

Boxes as tabs in your project workspace

The attach.openIn config key (CLI flag --attach-in) decides where an attached session lands. Under cmux:

# open each box as a tab in the current project's workspace
agentbox claude mybox --attach-in tab

# make that the default everywhere
agentbox config set attach.openIn tab

When you open several boxes from one project as tabs in the same workspace, the per-workspace colour can't say which tab needs input. So AgentBox also flags the individual tab whose agent needs input via a cmux notification — a tab badge, a reorder up the sidebar, and a desktop notification — which clears when you focus that tab to answer.

A shell in the box: Ctrl+a t

While attached, Ctrl+a opens a which-key menu in the footer; press a single key to act on the box. Ctrl+a t opens a fresh, persistent shell in the same box as a new cmux surface (a tab in the current pane).

A shell-in-box button + shortcut

You can also add a tab-bar button and keyboard shortcut that opens a shell in the current project's box (and behaves normally everywhere else). Add this to ~/.config/cmux/cmux.json and run cmux reload-config:

{
  "actions": {
    "agentbox-shell": {
      "type": "command",
      "title": "Shell in box",
      // Auto-pick the project's box; fall back to a normal login shell elsewhere.
      "command": "agentbox shell || exec $SHELL -l",
      "target": "newTabInCurrentPane",
      "icon": { "type": "symbol", "name": "terminal" },
      "shortcut": "cmd+shift+t",
    },
  },
  "ui": { "surfaceTabBar": { "buttons": ["cmux.newTerminal", "agentbox-shell"] } },
}

agentbox shell with no argument auto-picks the only box in the current directory's project; outside an AgentBox project it exits non-zero and the || exec $SHELL -l fallback opens an ordinary shell. This leaves cmux's standard Cmd+T (new surface) untouched. To make it be Cmd+T, set the action's shortcut to cmd+t and add "shortcuts": { "bindings": { "newSurface": "cmd+shift+t" } } to move the built-in off it.

The AgentBox Dock (right sidebar)

cmux's custom dock pins commands to the right sidebar. agentbox install cmux adds a panel there that runs agentbox list --cmux --watch — a compact, sidebar-tuned view (two short lines per box: name, then a colored status) so the live list of all your boxes, and what each agent is doing, stays visible while you work:

# add the AgentBox panel to ~/.config/cmux/dock.json
agentbox install cmux

# preview the JSON it would write, without touching anything
agentbox install cmux --dry-run

It upserts a single agentbox control and leaves any other dock controls (lazygit, logs, …) in place; re-running just updates it. The panel lists all your boxes, grouped by project under a dashed header — a dock control runs from your home directory, not the focused workspace, so it can't scope to "the current project".

Other flags: --height <points> (panel height, default 320), --title <text> (header, default AgentBox), and --force (reset an unparseable dock.json, backed up to dock.json.bak).

See Access your box for the rest of the ways to reach a box, and Configuration for the attach.openIn and attach.cmuxStatus keys.