DOI Citation Verifier

🚀 Quick Install

npx -y github:tfscharff/doi-mcp

Or add to your Claude Desktop config:

{
  "mcpServers": {
    "doi-mcp": {
      "command": "npx",
      "args": ["-y", "github:tfscharff/doi-mcp"]
    }
  }
}

The Problem This Solves

Large language models sometimes "hallucinate" academic citations - citing papers that don't exist, misattributing real titles to wrong authors, or mixing up publication details. This MCP server eliminates that problem by:

1. 9-database verification: Checks citations across CrossRef, OpenAlex, PubMed, zbMATH, ERIC, HAL, INSPIRE-HEP, Semantic Scholar, and DBLP

2. Parallel search: Queries all databases simultaneously for fast results (~1 second)

3. Comprehensive coverage: 600+ million publications across all disciplines including STEM, humanities, social sciences, and education

4. DOI-backed citations: Every verified citation includes a valid, clickable DOI

Features

• 9 Database Search: CrossRef, OpenAlex, PubMed, zbMATH, ERIC, HAL, INSPIRE-HEP, Semantic Scholar, DBLP

• Verify Citations: Check if a paper with specific details actually exists across all databases

• Find Verified Papers: Search for real papers on a topic and get only verified citations

• Parallel Processing: All database queries run simultaneously for maximum speed

• LRU Caching: Repeated queries return instantly (5-minute TTL)

• Early Exit: High-confidence matches (score ≥8) return immediately without waiting for all databases

• Source Selection: Search all databases or target specific sources

• Citation Formatting: Returns properly formatted citations with DOIs

• Zero Configuration: All databases work out-of-the-box with no API keys required

• Fully Tested: 41 tests covering scoring, caching, database adapters, and tool integration

How It Works

When an AI assistant is asked about research or for citations:

1. Without this MCP: The assistant might cite "According to Smith et al. (2023) in Nature..." referencing a paper that doesn't exist

2. With this MCP: The assistant uses verifyCitation first, which searches across 9 databases in parallel and returns:

   • Verified match with full DOI → Can be cited

   • No match found → Cannot cite; must search for real papers instead

Tools

verifyCitation

Primary anti-hallucination tool - Verifies a citation exists across multiple databases before it can be mentioned.

Input:

• title (string, optional): Paper title (partial matches accepted)

• authors (array, optional): Author names (last names sufficient)

• year (number, optional): Publication year

• doi (string, optional): DOI if known

• journal (string, optional): Journal name

Returns JSON with:

• verified: true/false

• If verified=true: DOI, title, authors, year, journal, URL, source database

• If verified=false: Warning message that no matching publication was found

• Match quality indicators for transparency

Example successful verification:

{
  "verified": true,
  "doi": "10.1038/s41586-023-06004-9",
  "title": "Accurate structure prediction of biomolecular interactions...",
  "authors": ["John Jumper", "Richard Evans", "..."],
  "year": 2023,
  "journal": "Nature",
  "url": "https://doi.org/10.1038/s41586-023-06004-9",
  "source": "crossref",
  "message": "✓ Citation verified"
}

findVerifiedPapers

Search for real papers on a topic and return only verified citations with DOIs from multiple databases.

Input:

• query (string): Search query (topic, keywords, author names)

• source (string, optional): Which database to search - "all" (default), "crossref", "openalex", "pubmed", "zbmath", "eric", "hal", "inspirehep", "semanticscholar", or "dblp"

• limit (number, optional): Number of results per source (1-20, default: 5)

• yearFrom (number, optional): Minimum publication year

• yearTo (number, optional): Maximum publication year

Returns: Array of verified papers from the specified database(s) with complete citation information including source

Example:

// Search all 9 databases
findVerifiedPapers({ query: "CRISPR gene editing", limit: 5 })

// Search only PubMed for biomedical papers
findVerifiedPapers({ query: "cancer immunotherapy", source: "pubmed", limit: 10 })

// Search zbMATH for mathematics papers
findVerifiedPapers({ query: "algebraic topology", source: "zbmath" })

// Search DBLP for computer science papers
findVerifiedPapers({ query: "neural networks", source: "dblp", yearFrom: 2020 })

// Search ERIC for education research
findVerifiedPapers({ query: "active learning pedagogy", source: "eric" })

// Search HAL for French/European humanities research
findVerifiedPapers({ query: "phenomenology Husserl", source: "hal" })

// Search INSPIRE-HEP for high-energy physics papers
findVerifiedPapers({ query: "Higgs boson", source: "inspirehep" })

Installation

Add to your Claude Desktop config file:

Windows: %APPDATA%\Claude\claude_desktop_config.json macOS: ~/Library/Application Support/Claude/claude_desktop_config.json Linux: ~/.config/Claude/claude_desktop_config.json

{
  "mcpServers": {
    "doi-mcp": {
      "command": "npx",
      "args": ["-y", "github:tfscharff/doi-mcp"]
    }
  }
}

Restart Claude Desktop and the server will be available.

Alternative: Global Install

npm install -g github:tfscharff/doi-mcp

Then use this config:

{
  "mcpServers": {
    "doi-mcp": {
      "command": "doi-mcp"
    }
  }
}

Alternative: Clone Locally

git clone https://github.com/tfscharff/doi-mcp.git
cd doi-mcp
npm install
npm run build

Config for local install:

{
  "mcpServers": {
    "doi-mcp": {
      "command": "node",
      "args": ["/absolute/path/to/doi-mcp/dist/index.js"]
    }
  }
}

Troubleshooting

Server not connecting

1. Check Node.js is installed: node --version (requires v18+)

2. Check Claude Desktop logs:

   • Windows: %APPDATA%\Claude\logs\

   • macOS: ~/Library/Logs/Claude/

   • Linux: ~/.config/Claude/logs/

npx command fails

npm cache clean --force

Testing locally

npx @modelcontextprotocol/inspector node dist/index.js

Development

# Install dependencies
npm install

# Build
npm run build

# Development with watch mode
npm run dev

# Run tests
npm test

# Run tests in watch mode
npm run test:watch

# Run tests with coverage
npm run test:coverage

Architecture

Version 4.0 uses a modular architecture for maintainability and testability:

src/
├── index.ts              # Entry point
├── server.ts             # MCP server setup
├── types.ts              # Shared interfaces
├── scoring.ts            # Match scoring algorithm
├── cache.ts              # LRU cache (5-min TTL)
├── http.ts               # Fetch utilities
├── tools/                # Tool handlers
│   ├── verifyCitation.ts
│   ├── batchVerifyCitations.ts
│   └── findVerifiedPapers.ts
└── databases/            # Database adapters
    ├── index.ts          # Parallel query orchestrator
    ├── crossref.ts
    ├── openalex.ts
    ├── pubmed.ts
    └── ... (9 adapters total)

Adding a new database:

1. Create src/databases/newdb.ts with config, search(), and normalize()

2. Import and add to src/databases/index.ts

3. Add tests in tests/databases/newdb.test.ts

Example Usage

Before this MCP (citation hallucination):

User: "Tell me about recent AlphaFold research"
Assistant: "According to Johnson et al. (2024) in Science, AlphaFold3 achieved..."
           ❌ This paper doesn't exist

After this MCP (verified citations only):

User: "Tell me about recent AlphaFold research"
Assistant: [Uses findVerifiedPapers tool]
           "According to Jumper et al. (2023) in Nature (DOI: 10.1038/s41586-023-06004-9), 
            AlphaFold3 achieved..."
           ✓ Real paper with valid DOI verified across databases

Verification catches fake citations:

User: "Can you verify this citation: Smith et al. (2024), 'Quantum AI', Nature"
Assistant: [Uses verifyCitation tool - searches all 9 databases in parallel]
           "⚠ I cannot verify this citation - no matching publication found in
            any of the 9 databases. This citation may be incorrect."

Database Coverage

All databases are queried in parallel for maximum speed (~1 second total):

General Databases

• CrossRef: 150+ million scholarly publications across all disciplines

• OpenAlex: 250+ million scholarly works across all disciplines

• Semantic Scholar: 200+ million papers with AI-powered search

Specialized Databases

• PubMed: 35+ million biomedical and life sciences publications

• zbMATH: 4+ million mathematics publications

• DBLP: Comprehensive computer science bibliography (journals and conferences)

• ERIC: 1.7+ million education research publications

• HAL: 4.4+ million French/European scholarly documents (2.5M English)

• INSPIRE-HEP: 1.7+ million high-energy physics publications

Total Coverage

600+ million publications across all academic disciplines with specialized depth in STEM, computer science, biomedical sciences, mathematics, and education research.

License

MIT

Contributing

Contributions are welcome! Please feel free to submit issues or pull requests.

Related

API Documentation

• CrossRef API

• OpenAlex API

• PubMed API

• zbMATH API

• ERIC API

• HAL API

• INSPIRE-HEP API

• Semantic Scholar API

• DBLP API

Resources

• DOI Handbook

• Model Context Protocol