Desktop Control via CUA Server

This skill allows OpenClaw to control the desktop using the CUA computer server API.

Prerequisites

• CUA computer server running on port 8000
• Access to localhost:8000 (or configured CUA_SERVER_URL)

Installation

To control your host desktop with OpenClaw, you need to install and run the CUA computer server on your machine.

Quick Start (Python SDK)

The easiest way to install the CUA computer server on your host:

# Install the Computer SDK
pip install cua-computer-sdk

# Start the server (it will control your current desktop)
cua-server start --port 8000

# Or if you need to specify the display (Linux/Unix)
DISPLAY=:0 cua-server start --port 8000

# Verify it's running
curl http://localhost:8000/status

Alternative: Install from Source

If you prefer to install from source:

# Clone the repository
git clone https://github.com/trycua/cua-computer-server
cd cua-computer-server

# Install dependencies
pip install -r requirements.txt

# Run the server
python -m cua_server --port 8000

Running as a Background Service

For always-on desktop control, set up as a system service:

macOS (launchd):

# Create a plist file
cat > ~/Library/LaunchAgents/com.cua.server.plist <<EOF
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>Label</key>
    <string>com.cua.server</string>
    <key>ProgramArguments</key>
    <array>
        <string>/usr/local/bin/cua-server</string>
        <string>start</string>
        <string>--port</string>
        <string>8000</string>
    </array>
    <key>RunAtLoad</key>
    <true/>
    <key>KeepAlive</key>
    <true/>
</dict>
</plist>
EOF

# Load the service
launchctl load ~/Library/LaunchAgents/com.cua.server.plist

# Start the service
launchctl start com.cua.server

Linux (systemd):

# Create service file
sudo tee /etc/systemd/system/cua-server.service > /dev/null <<EOF
[Unit]
Description=CUA Computer Server
After=network.target

[Service]
Type=simple
User=$USER
Environment="DISPLAY=:0"
Environment="XAUTHORITY=/home/$USER/.Xauthority"
ExecStart=/usr/local/bin/cua-server start --port 8000
Restart=always
RestartSec=10

[Install]
WantedBy=multi-user.target
EOF

# Enable and start the service
sudo systemctl daemon-reload
sudo systemctl enable cua-server
sudo systemctl start cua-server

# Check status
sudo systemctl status cua-server

Windows (Task Scheduler):

# Create a scheduled task to run at startup
$action = New-ScheduledTaskAction -Execute "cua-server.exe" -Argument "start --port 8000"
$trigger = New-ScheduledTaskTrigger -AtStartup
$principal = New-ScheduledTaskPrincipal -UserId "$env:USERNAME" -LogonType Interactive
$settings = New-ScheduledTaskSettingsSet -AllowStartIfOnBatteries -DontStopIfGoingOnBatteries

Register-ScheduledTask -TaskName "CUA Server" -Action $action -Trigger $trigger -Principal $principal -Settings $settings

Configuration Options

Configure the server for your needs:

# Basic start with default settings
cua-server start

# Custom port
cua-server start --port 8001

# With authentication token (recommended if exposing to network)
cua-server start --port 8000 --auth-token your-secret-token

# Specify display (Linux/Unix)
DISPLAY=:1 cua-server start --port 8000

# Bind to all interfaces (careful - exposes to network!)
cua-server start --bind 0.0.0.0 --port 8000 --auth-token required-if-exposed

Security Considerations

⚠️ Important: By default, the server only listens on localhost (127.0.0.1) for security. This means only processes on your machine can connect to it.

• Local only (default): Safe for personal use with OpenClaw
• Network exposure: Only use --bind 0.0.0.0 with proper firewall rules AND authentication
• Authentication: Always use --auth-token if the server is accessible from the network

Verification

After installation, verify the server is working:

# Check server status
curl http://localhost:8000/status

# List available commands
curl http://localhost:8000/commands | jq

# Take a test screenshot of your desktop
curl -X POST http://localhost:8000/cmd \
  -H "Content-Type: application/json" \
  -d '{"command": "screenshot"}' \
  | jq -r '.result.base64' \
  | base64 -d > test-screenshot.png

# View the screenshot
open test-screenshot.png       # macOS
xdg-open test-screenshot.png   # Linux
start test-screenshot.png      # Windows

If you see a screenshot of your current desktop, the server is working correctly!

Troubleshooting

Port Already in Use:

# Check what's using port 8000
lsof -i :8000              # macOS/Linux
netstat -ano | findstr :8000  # Windows

# Solution: Use a different port
cua-server start --port 8001

Permission Denied (Linux):

# You may need to add your user to the input group for keyboard/mouse control
sudo usermod -a -G input $USER
# Log out and back in for changes to take effect

Display Not Found (Linux):

# Check your display variable
echo $DISPLAY

# Set it explicitly
DISPLAY=:0 cua-server start --port 8000

Server Not Responding:

# Check if the process is running
ps aux | grep cua-server       # Linux/macOS
tasklist | findstr cua-server  # Windows

# Try running in foreground to see errors
cua-server start --port 8000 --debug

Available Commands

Take Screenshot

Capture the current screen:

curl -X POST http://localhost:8000/cmd \
  -H "Content-Type: application/json" \
  -d '{"command": "screenshot"}' \
  | jq -r '.result.base64' \
  | base64 -d > screenshot.png

Click at Coordinates

Click at specific x,y coordinates:

# Click at center of 1280x720 screen
curl -X POST http://localhost:8000/cmd \
  -H "Content-Type: application/json" \
  -d '{"command": "left_click", "params": {"x": 640, "y": 360}}'

Right Click

curl -X POST http://localhost:8000/cmd \
  -H "Content-Type: application/json" \
  -d '{"command": "right_click", "params": {"x": 640, "y": 360}}'

Double Click

curl -X POST http://localhost:8000/cmd \
  -H "Content-Type: application/json" \
  -d '{"command": "double_click", "params": {"x": 640, "y": 360}}'

Type Text

Type text at the current cursor position:

curl -X POST http://localhost:8000/cmd \
  -H "Content-Type: application/json" \
  -d '{"command": "type_text", "params": {"text": "Hello, World!"}}'

Press Hotkey

Press a key combination:

# Ctrl+C
curl -X POST http://localhost:8000/cmd \
  -H "Content-Type: application/json" \
  -d '{"command": "hotkey", "params": {"keys": ["ctrl", "c"]}}'

# Ctrl+Alt+T (open terminal)
curl -X POST http://localhost:8000/cmd \
  -H "Content-Type: application/json" \
  -d '{"command": "hotkey", "params": {"keys": ["ctrl", "alt", "t"]}}'

Press Single Key

Press a single key:

# Press Enter
curl -X POST http://localhost:8000/cmd \
  -H "Content-Type: application/json" \
  -d '{"command": "press_key", "params": {"key": "enter"}}'

# Press Escape
curl -X POST http://localhost:8000/cmd \
  -H "Content-Type: application/json" \
  -d '{"command": "press_key", "params": {"key": "escape"}}'

Move Cursor

Move cursor to specific position:

curl -X POST http://localhost:8000/cmd \
  -H "Content-Type: application/json" \
  -d '{"command": "move_cursor", "params": {"x": 100, "y": 200}}'

Scroll

Scroll up or down:

# Scroll down 3 units
curl -X POST http://localhost:8000/cmd \
  -H "Content-Type: application/json" \
  -d '{"command": "scroll_direction", "params": {"direction": "down", "amount": 3}}'

# Scroll up 5 units
curl -X POST http://localhost:8000/cmd \
  -H "Content-Type: application/json" \
  -d '{"command": "scroll_direction", "params": {"direction": "up", "amount": 5}}'

Launch Application

Launch an application by name:

# Launch Firefox
curl -X POST http://localhost:8000/cmd \
  -H "Content-Type: application/json" \
  -d '{"command": "launch", "params": {"app": "firefox"}}'

# Launch Terminal
curl -X POST http://localhost:8000/cmd \
  -H "Content-Type: application/json" \
  -d '{"command": "launch", "params": {"app": "xfce4-terminal"}}'

Open File or URL

Open a file or URL with default application:

# Open URL
curl -X POST http://localhost:8000/cmd \
  -H "Content-Type: application/json" \
  -d '{"command": "open", "params": {"path": "https://example.com"}}'

# Open file
curl -X POST http://localhost:8000/cmd \
  -H "Content-Type: application/json" \
  -d '{"command": "open", "params": {"path": "/home/cua/document.txt"}}'

Get Window Information

Get current window ID:

curl -X POST http://localhost:8000/cmd \
  -H "Content-Type: application/json" \
  -d '{"command": "get_current_window_id"}'

Window Control

Maximize window:

curl -X POST http://localhost:8000/cmd \
  -H "Content-Type: application/json" \
  -d '{"command": "maximize_window", "params": {"window_id": "0x1234567"}}'

Minimize window:

curl -X POST http://localhost:8000/cmd \
  -H "Content-Type: application/json" \
  -d '{"command": "minimize_window", "params": {"window_id": "0x1234567"}}'

Demo Workflows

Browser Navigation Demo

Open Firefox and navigate to a website:

# Take initial screenshot
curl -X POST http://localhost:8000/cmd -H "Content-Type: application/json" -d '{"command": "screenshot"}' -o initial.json

# Launch Firefox
curl -X POST http://localhost:8000/cmd -H "Content-Type: application/json" -d '{"command": "launch", "params": {"app": "firefox"}}'
sleep 3

# Focus address bar (Ctrl+L)
curl -X POST http://localhost:8000/cmd -H "Content-Type: application/json" -d '{"command": "hotkey", "params": {"keys": ["ctrl", "l"]}}'
sleep 1

# Type URL
curl -X POST http://localhost:8000/cmd -H "Content-Type: application/json" -d '{"command": "type_text", "params": {"text": "https://example.com"}}'

# Press Enter
curl -X POST http://localhost:8000/cmd -H "Content-Type: application/json" -d '{"command": "press_key", "params": {"key": "enter"}}'
sleep 5

# Take final screenshot
curl -X POST http://localhost:8000/cmd -H "Content-Type: application/json" -d '{"command": "screenshot"}' -o final.json

Text Editor Demo

Open text editor and type content:

# Open terminal
curl -X POST http://localhost:8000/cmd -H "Content-Type: application/json" -d '{"command": "hotkey", "params": {"keys": ["ctrl", "alt", "t"]}}'
sleep 2

# Type command to open text editor
curl -X POST http://localhost:8000/cmd -H "Content-Type: application/json" -d '{"command": "type_text", "params": {"text": "mousepad"}}'
curl -X POST http://localhost:8000/cmd -H "Content-Type: application/json" -d '{"command": "press_key", "params": {"key": "enter"}}'
sleep 2

# Type some text
curl -X POST http://localhost:8000/cmd -H "Content-Type: application/json" -d '{"command": "type_text", "params": {"text": "Hello from OpenClaw!\nThis is automated desktop control."}}'

# Save file (Ctrl+S)
curl -X POST http://localhost:8000/cmd -H "Content-Type: application/json" -d '{"command": "hotkey", "params": {"keys": ["ctrl", "s"]}}'
sleep 1

# Type filename
curl -X POST http://localhost:8000/cmd -H "Content-Type: application/json" -d '{"command": "type_text", "params": {"text": "openclaw-demo.txt"}}'
curl -X POST http://localhost:8000/cmd -H "Content-Type: application/json" -d '{"command": "press_key", "params": {"key": "enter"}}'

Form Filling Demo

Fill out a web form:

# Assuming browser is open with form visible

# Click on first input field (adjust coordinates)
curl -X POST http://localhost:8000/cmd -H "Content-Type: application/json" -d '{"command": "left_click", "params": {"x": 400, "y": 300}}'

# Type name
curl -X POST http://localhost:8000/cmd -H "Content-Type: application/json" -d '{"command": "type_text", "params": {"text": "John Doe"}}'

# Tab to next field
curl -X POST http://localhost:8000/cmd -H "Content-Type: application/json" -d '{"command": "press_key", "params": {"key": "tab"}}'

# Type email
curl -X POST http://localhost:8000/cmd -H "Content-Type: application/json" -d '{"command": "type_text", "params": {"text": "john@example.com"}}'

# Tab to next field
curl -X POST http://localhost:8000/cmd -H "Content-Type: application/json" -d '{"command": "press_key", "params": {"key": "tab"}}'

# Type message
curl -X POST http://localhost:8000/cmd -H "Content-Type: application/json" -d '{"command": "type_text", "params": {"text": "This form was filled automatically by OpenClaw!"}}'

# Submit form (click submit button)
curl -X POST http://localhost:8000/cmd -H "Content-Type: application/json" -d '{"command": "left_click", "params": {"x": 400, "y": 500}}'

Helper Functions

Check Server Status

curl http://localhost:8000/status

List All Available Commands

curl http://localhost:8000/commands | jq

Get Screen Size

curl -X POST http://localhost:8000/cmd \
  -H "Content-Type: application/json" \
  -d '{"command": "get_screen_size"}'

Get Cursor Position

curl -X POST http://localhost:8000/cmd \
  -H "Content-Type: application/json" \
  -d '{"command": "get_cursor_position"}'

Environment Variables

• CUA_SERVER_URL: Base URL for CUA server (default: http://localhost:8000)

Tips

1. Wait Between Commands: Add sleep between commands to allow UI to update
2. Check Coordinates: Screen is 1280x720, center is at (640, 360)
3. Screenshot for Debugging: Take screenshots before and after actions to verify
4. Use Variables: Store coordinates and text in variables for reusability

Example OpenClaw Usage

Once this skill is loaded, you can use it in OpenClaw conversations:

User: "Take a screenshot and open Firefox"
OpenClaw: *executes the screenshot and launch firefox commands*

User: "Type 'Hello World' in the current window"
OpenClaw: *executes the type_text command*

User: "Click at the center of the screen"
OpenClaw: *executes click command at 640,360*

Troubleshooting

1. Connection Refused: Make sure CUA server is running on port 8000
2. No Response: Check if you're in the container or have SSH tunnel set up
3. Commands Not Working: Verify with curl http://localhost:8000/status
4. Wrong Coordinates: Remember screen is 1280x720, adjust coordinates accordingly