DWFlanagan/citation-verifier-mcp

Citation Verifier MCP Server

A Model Context Protocol (MCP) server that provides citation verification capabilities to Claude and other MCP-compatible AI assistants.

This server wraps the llm-citation-verifier library to expose citation verification as an MCP tool.

Features

• ✅ Verify DOI citations against the Crossref database
• ✅ Detect hallucinated citations by checking if DOIs actually exist
• ✅ Extract bibliographic metadata (title, authors, journal, year)
• ✅ Clean, formatted output with clear verification status
• ✅ No API keys required - uses public Crossref API
• 🆕 Remote access support - Deploy as a web service for remote MCP clients
• 🆕 WebSocket & HTTP endpoints - Compatible with web-based MCP clients

Installation

Prerequisites

• Python 3.10+
• Claude Desktop (for local testing)

Local Installation

# Clone the repository
git clone https://github.com/dwflanagan/citation-verifier-mcp.git
cd citation-verifier-mcp

# Initialize uv project and install dependencies
uv sync

# Activate the virtual environment
source .venv/bin/activate  # On Windows: .venv\Scripts\activate

Usage

Local MCP Server (Claude Desktop)

This is the traditional way to use the server with Claude Desktop locally.

With Claude Desktop

1. Add to your Claude Desktop configuration (claude_desktop_config.json):

{
  "mcpServers": {
    "citation-verifier": {
      "command": "python",
      "args": ["-m", "citation_verifier_mcp.server"]
    }
  }
}

2. Restart Claude Desktop
3. The citation verification tool will be available in your conversations:

You: Can you verify this DOI for me: 10.1038/nature12373

Claude: I'll verify that DOI using the citation verification tool.

[Tool call: verify_citation with DOI "10.1038/nature12373"]

# ✅ Citation Verified

**DOI:** 10.1038/nature12373
**Title:** A quantum gas of deeply bound ground state molecules
**Authors:** T. Takekoshi, L. Reichsöllner, et al.
**Journal:** Nature
**Publisher:** Springer Science and Business Media LLC
**Year:** 2014
**URL:** https://doi.org/10.1038/nature12373

This DOI exists in the Crossref database and appears to be a legitimate citation.

Remote MCP Server (Web Service)

🆕 New! You can now run the Citation Verifier as a remote web service, similar to the Cloudflare MCP example.

Quick Start

# Start the remote server
./launch_remote_server.sh

# Or manually:
uv run python start_server.py

The server will be available at http://localhost:8000 with these endpoints:

• WebSocket: ws://localhost:8000/mcp (for MCP clients)
• Health Check: http://localhost:8000/health
• API Info: http://localhost:8000/

Connect Claude Desktop to Remote Server

1. Install the mcp-remote proxy:

   npm install -g mcp-remote
   

2. Update your Claude Desktop configuration:

   {
     "mcpServers": {
       "citation-verifier-remote": {
         "command": "npx",
         "args": ["mcp-remote", "ws://localhost:8000/mcp"]
       }
     }
   }
   

3. Restart Claude Desktop

Deploy to Production

See for detailed deployment instructions including:

• Cloud deployment (Render.com)
• Simple deployment to cloud platforms
• Production configuration
• Security considerations

Development

# Install with development dependencies (already done with uv sync)
uv sync

# Run tests
uv run pytest

# Lint code
uv run ruff check .

# Type check
uv run mypy src/

# Run the server for testing
uv run python -m citation_verifier_mcp.server

Tool Reference

verify_citation

Verifies a DOI citation against the Crossref database.

Parameters:

• doi (string, required): The DOI to verify. Can include URL prefixes like https://doi.org/ which will be automatically stripped.

Returns:

• Formatted verification result with bibliographic metadata if verified
• Error message and recommendations if not verified

Example DOIs to try:

• 10.1038/nature12373 (real paper)
• 10.1234/fake.doi.2024 (fake DOI)

How It Works

This MCP server:

1. Receives DOI verification requests from MCP clients (like Claude)
2. Uses the llm-citation-verifier library to query the Crossref API
3. Returns formatted results indicating whether the DOI exists and includes metadata

The underlying verification process:

• Cleans DOI input (removes URL prefixes, whitespace)
• Queries Crossref REST API
• Extracts and formats bibliographic metadata
• Provides clear verification status

Use Cases

• Research assistance: Verify citations in AI-generated content
• Academic writing: Check DOIs before publication
• Fact-checking: Validate suspicious citations
• Quality control: Audit AI tools for citation hallucination

Contributing

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Add tests
5. Submit a pull request

License

MIT License - see LICENSE file for details.

Related Projects

• llm-citation-verifier - The core citation verification library
• Model Context Protocol - The protocol specification