Cmux

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.

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"