cmux

---

name: cmux

description: "Control cmux terminal multiplexer via its Unix socket API. Use when needing to: (1) List, create, select, or close workspaces; (2) Split panes and manage surfaces; (3) Send text or key presses to terminals; (4) Create notifications; (5) Set sidebar status, progress bars, or log entries; (6) Query system state. Requires cmux CLI or Unix socket at /tmp/cmux.sock."

---

# cmux

Control cmux terminal multiplexer programmatically via its Unix socket API or CLI.

Socket Connection

SOCKET_PATH="${CMUX_SOCKET_PATH:-/tmp/cmux.sock}"

Send JSON-RPC requests:

{"id":"req-1","method":"workspace.list","params":{}}

CLI Quick Reference

# Output as JSON
cmux --json <command>

# Target specific workspace/surface
cmux --workspace <id> --surface <id> <command>

Workspace

| Action | CLI | Socket Method |

|--------|-----|---------------|

| List all | `cmux list-workspaces` | `workspace.list` |

| Create new | `cmux new-workspace` | `workspace.create` |

| Select | `cmux select-workspace --workspace <id>` | `workspace.select` |

| Get current | `cmux current-workspace` | `workspace.current` |

| Close | `cmux close-workspace --workspace <id>` | `workspace.close` |

Splits & Surfaces

| Action | CLI | Socket Method |

|--------|-----|---------------|

| New split | `cmux new-split <direction>` | `surface.split` (direction: left/right/up/down) |

| List surfaces | `cmux list-surfaces` | `surface.list` |

| Focus surface | `cmux focus-surface --surface <id>` | `surface.focus` |

Input

| Action | CLI | Socket Method |

|--------|-----|---------------|

| Send text | `cmux send "echo hello"` | `surface.send_text` |

| Send key | `cmux send-key enter` | `surface.send_key` |

| Send to surface | `cmux send-surface --surface <id> "cmd"` | `surface.send_text` (with surface_id) |

Keys: `enter`, `tab`, `escape`, `backspace`, `delete`, `up`, `down`, `left`, `right`

Notifications

cmux notify --title "Title" --body "Body"
# Socket: notification.create

Sidebar Metadata

| Action | CLI | Socket Method |

|--------|-----|---------------|

| Set status | `cmux set-status <key> <value>` | (socket only) |

| Clear status | `cmux clear-status <key>` | (socket only) |

| Set progress | `cmux set-progress 0.5 --label "Building..."` | (socket only) |

| Clear progress | `cmux clear-progress` | (socket only) |

| Log entry | `cmux log "message" --level error` | (socket only) |

| Clear log | `cmux clear-log` | (socket only) |

System

| Action | CLI | Socket Method |

|--------|-----|---------------|

| Ping | `cmux ping` | `system.ping` |

| Capabilities | `cmux capabilities` | `system.capabilities` |

| Identify context | `cmux identify` | `system.identify` |

Python Client

import json
import os
import socket

SOCKET_PATH = os.environ.get("CMUX_SOCKET_PATH", "/tmp/cmux.sock")

def rpc(method, params=None, req_id=1):
    payload = {"id": req_id, "method": method, "params": params or {}}
    with socket.socket(socket.AF_UNIX, socket.SOCK_STREAM) as sock:
        sock.connect(SOCKET_PATH)
        sock.sendall(json.dumps(payload).encode("utf-8") + b"\n")
        return json.loads(sock.recv(65536).decode("utf-8"))

# List workspaces
print(rpc("workspace.list", req_id="ws"))

# Send notification
print(rpc("notification.create", {"title": "Hello", "body": "From Python!"}))

Shell Helper

cmux_cmd() {
    SOCK="${CMUX_SOCKET_PATH:-/tmp/cmux.sock}"
    printf "%s\n" "$1" | nc -U "$SOCK"
}

cmux_cmd '{"id":"ws","method":"workspace.list","params":{}}'

Check if cmux is Available

[ -S "${CMUX_SOCKET_PATH:-/tmp/cmux.sock}" ] && echo "cmux socket available"
command -v cmux &>/dev/null && echo "cmux CLI available"