Terminal Control MCP

A Model Context Protocol (MCP) server that enables AI agents to interact with terminal-based TUI applications through a virtual X11 display approach.

Overview

This project provides a comprehensive solution for controlling terminal applications programmatically using:

• Xvfb for headless virtual X11 display
• xterm for terminal emulation
• xdotool for input simulation and window management
• ImageMagick for PNG screenshot capture

The system captures actual visual terminal output as PNG screenshots, making it ideal for AI agents that need to see and interact with terminal applications.

Features

• Virtual Display Management: Headless X11 display using Xvfb
• Input Simulation: Send keyboard input and text to terminal applications
• Screenshot Capture: Take PNG screenshots of terminal output
• Window Management: Reliable window detection and focus handling
• Resource Cleanup: Proper process management with timeout handling

System Requirements

The following system packages must be installed:

# Ubuntu/Debian
sudo apt-get install xvfb xterm xdotool imagemagick

# CentOS/RHEL/Fedora
sudo yum install xorg-x11-server-Xvfb xterm xdotool ImageMagick

Installation

This project uses the uv package manager:

# Clone the repository
git clone <repository-url>
cd terminal-control-mcp

# Install dependencies
uv sync

# Activate virtual environment
source .venv/bin/activate

Quick Start

Running the Example

Try the included htop example to see the system in action:

python examples/example_htop.py

This will:

1. Launch htop in a virtual xterm session
2. Press F3 to open the search dialog
3. Type "python" as a search term
4. Capture PNG screenshots at each step
5. Clean up all processes

Basic Usage

from examples.example_htop import XTermSession

# Create a session
session = XTermSession(width=1920, height=1080)

try:
    # Start virtual display and terminal
    session.start_virtual_display()
    session.start_xterm("your-command-here")
    
    # Take a screenshot
    session.take_screenshot("output.png")
    
    # Send input
    session.send_key("F1")
    session.send_text("hello world")
    
finally:
    session.cleanup()

Architecture

Core Components

1. XTermSession Class: The main interface for terminal control

   • Manages Xvfb virtual display lifecycle
   • Spawns and controls xterm processes
   • Handles input simulation via xdotool
   • Captures screenshots using ImageMagick

2. Virtual Display Approach: Unlike direct TTY manipulation, this system:

   • Creates a real X11 environment with Xvfb
   • Launches actual xterm instances
   • Captures genuine visual output as PNG files
   • Provides reliable input simulation

Key Methods

• start_virtual_display(): Initialize Xvfb virtual display
• start_xterm(command): Launch xterm with specified command
• send_key(key): Send special keys (F1, Escape, etc.)
• send_text(text): Send alphanumeric text input
• take_screenshot(filename): Capture PNG screenshot
• cleanup(): Properly terminate all processes

Development

Project Structure

terminal-control-mcp/
├── src/terminal_control_mcp/    # Main MCP server implementation (planned)
├── examples/
│   ├── example_htop.py         # Reference implementation
│   └── README.md
├── tests/                      # Test suite
├── pyproject.toml             # Project configuration
└── CLAUDE.md                  # Development guidelines

Development Commands

# Run the main application
python main.py

# Run the htop example
python examples/example_htop.py

# Activate virtual environment
source .venv/bin/activate

MCP Server Implementation (Planned)

The full MCP server will provide these tools:

• terminal_launch: Start a new terminal session
• terminal_input: Send keyboard/text input
• terminal_capture: Take PNG screenshot
• terminal_close: Clean up terminal session

Technical Details

Window Detection

The system uses multiple fallback strategies for reliable window ID detection:

search_methods = [
    ['xdotool', 'search', '--class', 'XTerm'],
    ['xdotool', 'search', '--name', 'xterm'],
    ['xdotool', 'search', '--class', 'xterm'],
    ['xdotool', 'getactivewindow']
]

Screenshot Capture

Uses ImageMagick's import command for reliable PNG capture:

subprocess.run(['import', '-window', 'root', filename], env=env)

Resource Management

Implements proper cleanup with timeout handling:

def cleanup(self):
    if self.xterm_proc:
        self.xterm_proc.terminate()
        try:
            self.xterm_proc.wait(timeout=5)
        except subprocess.TimeoutExpired:
            self.xterm_proc.kill()

Contributing

[TBD]