MCP Content Credentials Server

MCP (Model Context Protocol) server for reading C2PA Content Credentials from images and videos. Detects credentials from both embedded manifests and invisible watermarks.

Features

🔍 Embedded C2PA Detection - Read manifests from file metadata
🌊 TrustMark Watermark Detection - Detect credentials in image pixels (survives social media!)
🌐 URL Support - Check credentials from web URLs
📂 Direct Filesystem Access - Claude can browse your directories
⚡ Smart Detection - Checks embedded first, watermark as fallback
🤖 Automatic Installation - Zero configuration setup
📋 Structured Output - Human-readable parsed data
🛡️ Production Ready - Full error handling and logging
🌐 REST API - HTTP endpoints for ChatGPT and web integration

Quick Start

# 1. Clone
git clone https://github.com/noga7/mcp-content-credentials.git
cd mcp-content-credentials

# 2. Install (automatic: installs c2patool + TrustMark)
npm install

# 3. Build
npm run build

# 4. Configure Claude Desktop
# Add to ~/Library/Application Support/Claude/claude_desktop_config.json:
{
  "mcpServers": {
    "content-credentials": {
      "command": "node",
      "args": ["/absolute/path/to/mcp-content-credentials/build/index.js"]
    }
  }
}

# 5. Restart Claude Desktop

# Optional: Start REST API for ChatGPT/web access
npm run start:api
# Server runs on http://localhost:3000

REST API (for ChatGPT & Web Apps)

Want to use this with ChatGPT or your own web app? Start the HTTP REST API:

npm run start:api

The server runs on http://localhost:3000. See REST-API.md for full documentation.

For ChatGPT: Use ngrok to expose your local server, or deploy to Render/Railway. See REST-API.md for instructions.

# Quick test
curl "http://localhost:3000/verify-url?url=https://example.com/image.jpg"

Prerequisites

Node.js v18+
Python 3.8.5+ (for TrustMark watermarks)

All other dependencies auto-install during npm install:

✅ c2patool (Homebrew on macOS, binary on Linux)
✅ TrustMark Python package (via pip)

Manual Installation (if auto-install fails)

# c2patool
brew install contentauth/tools/c2patool  # macOS

# TrustMark
pip3 install trustmark Pillow

# Or retry auto-install
npm run install-deps

Usage

Check a Specific File

"Check content credentials in ~/Desktop/photo.jpg"
"Is this image AI-generated?"
"Who created /Users/you/Downloads/image.png?"

Browse Directories

"What images are in my Desktop?"
"Check my Downloads for Content Credentials"
"Find AI-generated images in my Pictures"

Check URLs

"Check credentials at https://example.com/image.jpg"

How It Works

Detection Flow

1. Check Embedded C2PA Manifest (fast: ~150ms)
   ↓
   Found? → Return immediately ✅
   ↓
2. Check TrustMark Watermark (slower: ~600ms)
   ↓
   Found? → Return watermark data ✅
   ↓
3. Neither found → "No Content Credentials found" ❌

Why This Order?

Performance: 80% of credentialed images have embedded manifests
Speed: Skip expensive watermark check when not needed
Completeness: Still catch stripped metadata via watermarks

TrustMark Watermarks

Invisible watermarks embedded in image pixels that:

✅ Survive JPEG compression
✅ Persist through social media uploads (Instagram, Twitter)
✅ Work after print-scan cycles
✅ Remain when metadata is stripped

Supported Formats

Images: JPEG, PNG, WebP, GIF, TIFF, AVIF, HEIC
Video: MP4, MOV

API Response

{
  success: boolean;
  hasCredentials: boolean;
  
  // Embedded C2PA data
  manifestData?: {
    whoThisComesFrom?: {
      linkedInIdentity?: { name, profileUrl, verified }
      otherIdentities?: [{ name, socialAccounts }]
    };
    aboutThisContent?: {
      actions?: [{ action, softwareAgent, when }]
      genAIInfo?: { generative, training, model }
    };
    aboutTheseCredentials?: { claimSigner, timestamp };
    validationInfo?: { certificate, trustInfo };
  };
  
  // Watermark data (if no embedded found)
  trustMarkData?: {
    identifier: string;    // Watermark payload
    schema: string;        // BCH_SUPER, BCH_5, etc.
    manifestUrl?: string;  // URL to full manifest
  };
  
  error?: string;
}

Filesystem Access

Claude can browse these directories automatically:

~/Desktop
~/Downloads
~/Documents
~/Pictures

No need to provide exact paths! Just ask:

"What images are in my Desktop?"
"Check recent downloads"

Development

npm run build        # Compile TypeScript
npm run dev          # Development mode
npm run lint         # Check code quality
npm run test         # Run tests
npm run precommit    # Full quality check

Architecture

mcp-content-credentials/
├── src/
│   ├── index.ts              # MCP server + filesystem access
│   ├── c2pa-service.ts       # Detection orchestration
│   ├── trustmark-service.ts  # Watermark detection (Python)
│   ├── parsers/              # Data formatters
│   └── types/                # TypeScript definitions
├── scripts/
│   ├── install-trustmark.cjs # Auto-installer
│   └── trustmark-decode.py   # Python watermark decoder
└── build/                    # Compiled output

Troubleshooting

"Unable to access that file"

Restart Claude Desktop (most common fix!)
Use absolute paths: /Users/you/... not ~/...
Verify MCP is connected: Ask "What tools do you have?"

"c2patool: command not found"

brew install contentauth/tools/c2patool  # macOS
# or
npm run install-deps

"Python or TrustMark not found"

pip3 install trustmark Pillow
# or
npm run install-deps

No Content Credentials Found

This is normal! The file either:

Wasn't created with content authentication
Had credentials removed
Is a screenshot/copy without provenance

Performance

Embedded check: ~150ms (fast path, 80% of cases)
+ Watermark check: ~600ms (fallback, 20% of cases)
First watermark: ~30s (downloads ONNX model, one-time)

Security

✅ Read-only filesystem access
✅ Limited to user directories (Desktop, Downloads, etc.)
✅ Input validation on all paths and URLs
✅ Temporary files auto-deleted
✅ No access to hidden/system files

Contributing

See CONTRIBUTING.md

Resources

License

MIT