🔐 TextWatermarking MCP Server

A Unicode-based text watermarking MCP (Model Context Protocol) server that embeds invisible watermarks using variation selectors. Perfect for AI applications, content protection, and text authentication.

✨ Features

• 🔒 Invisible Watermarking: Embed secret text using Unicode variation selectors
• ⚡ Fast & Robust Algorithms: Multiple encoding strategies for different use cases
• 🤖 Cursor AI Integration: Ready-to-use MCP server for Cursor and other AI tools
• 🚀 Zero Configuration: Works out of the box with npx
• 🔑 Secure API: Token-based authentication
• 📱 Cross-Platform: Works on Windows, macOS, and Linux

🚀 Quick Start

📋 Prerequisites: You'll need an API token from TextWatermarking.com (free registration required).

Using with npx (Recommended)

# Run with command-line token
npx @textwatermarking/mcp-server --token YOUR_API_TOKEN

# Or with environment variable
USER_API_TOKEN="your_token_here" npx @textwatermarking/mcp-server

Using with Cursor AI

Add to your mcp.json configuration:

{
  "mcpServers": {
    "watermark-mcp": {
      "command": "npx",
      "args": [
        "@textwatermarking/mcp-server",
        "--token",
        "YOUR_API_TOKEN"
      ],
      "description": "Text watermarking with invisible Unicode markers"
    }
  }
}

📦 Installation

Global Installation

npm install -g @textwatermarking/mcp-server

Local Installation

npm install @textwatermarking/mcp-server

🔧 Configuration

Getting Your API Token

⚠️ Important: You need a valid API token to use this MCP server.

Step 1: Register for an Account

1. Visit TextWatermarking.com
2. Create a free account or sign in to your existing account
3. Navigate to your account dashboard or API settings

Step 2: Generate Your API Token

1. In your account dashboard, find the "API Keys" or "API Tokens" section
2. Generate a new API token for MCP server usage
3. Copy the token securely (you'll need it for configuration)

Step 3: Configure the Token

Once you have your API token, configure it using one of these methods:

Method 1: Command Line (Recommended for Cursor)

watermark-mcp --token YOUR_API_TOKEN

Method 2: Environment Variable

export USER_API_TOKEN="YOUR_API_TOKEN"
watermark-mcp

Method 3: Cursor MCP Configuration

{
  "mcpServers": {
    "watermark-mcp": {
      "command": "npx",
      "args": ["@textwatermarking/mcp-server", "--token", "YOUR_API_TOKEN"]
    }
  }
}

Available Options

watermark-mcp [options]

Options:
  --token, -t <token>    API token for authentication
  --api-url, -u <url>    API base URL (default: https://api.textwatermarking.com)
  --help, -h             Show help message

🛠️ Available Tools

Fast Encoding/Decoding

• fast_encode: Quick watermark embedding
• fast_decode: Quick watermark extraction

Robust Encoding/Decoding

• robust_encode: Advanced watermarking with stealth levels
• robust_decode: Extract robust watermarks

Example Usage

// Fast encoding
const result = await mcp.call("fast_encode", {
  visible_text: "Hello World",
  hidden_text: "Secret Message"
});

// Returns: "H󠅄󠅘󠅙󠅣󠄐󠅙󠅣󠄐󠅑󠄐󠅣󠅕󠅓󠅢󠅕󠅤"

// Fast decoding
const decoded = await mcp.call("fast_decode", {
  input_text: "H󠅄󠅘󠅙󠅣󠄐󠅙󠅣󠄐󠅑󠄐󠅣󠅕󠅓󠅢󠅕󠅤"
});

// Returns: "Secret Message"

🔍 How It Works

This MCP server uses Unicode Variation Selectors to embed invisible watermarks:

1. Encoding: Hidden text is converted to Unicode variation selectors
2. Embedding: Selectors are inserted between characters in the visible text
3. Invisibility: The watermarked text appears identical to the original
4. Decoding: Variation selectors are extracted and converted back to hidden text

📚 API Reference

fast_encode

Embeds hidden text using the fast algorithm.

Parameters:

• visible_text (string): Text shown to users
• hidden_text (string): Secret text to embed

Returns: Watermarked text with invisible markers

fast_decode

Extracts hidden text using the fast algorithm.

Parameters:

• input_text (string): Text that may contain watermarks

Returns: Extracted hidden text or empty if none found

robust_encode

Advanced watermarking with configurable stealth levels.

Parameters:

• visible_text (string): Text shown to users
• hidden_text (string): Secret text to embed
• stealth_level (optional): "standard" | "high" | "maximum"
• distribution (optional): "even" | "random"

Returns: Watermarked text with robust encoding

robust_decode

Extracts robust watermarks.

Parameters:

• input_text (string): Text with potential robust watermarks

Returns: Extracted hidden text

🚨 Troubleshooting

Common Issues

❌ "Authentication failed"

• Verify your API token is correct
• Check token hasn't expired
• Ensure token is properly set via --token or USER_API_TOKEN
• If you don't have a token, register at TextWatermarking.com

❌ "Need help getting an API token?"

• Visit TextWatermarking.com to register
• Contact support at [email protected]
• Check the API documentation for detailed setup instructions

❌ "Command not found: watermark-mcp"

• Use npx @textwatermarking/mcp-server instead
• Or install globally: npm install -g @textwatermarking/mcp-server

❌ "MCP server connection failed"

• Ensure you're using the correct MCP configuration
• Check that all dependencies are installed
• Verify Node.js version (requires ≥18.0.0)

🤝 Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

🔗 Links

• API Documentation: https://textwatermarking.com/docs
• Support: [email protected]
• Issues: GitHub Issues

⭐ Show Your Support

Give a ⭐️ if this project helped you!

Made with ❤️ by the TextWatermarking Team