DOI Citation Verifier MCP Server

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A Model Context Protocol (MCP) server that prevents citation hallucination by verifying academic citations against multiple authoritative databases. This server enables AI assistants to verify every citation against real publications in CrossRef, OpenAlex, and PubMed before citing them.

The Problem This Solves

Large language models often "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:

Multi-source verification: Checks citations across CrossRef (150+ million publications), OpenAlex (250+ million works), and PubMed (35+ million biomedical papers)
Real-time validation: Searches multiple authoritative databases to confirm publications exist
Comprehensive coverage: Combines general academic literature (CrossRef, OpenAlex) with specialized biomedical sources (PubMed)
DOI-backed citations: Every verified citation includes a valid, clickable DOI

Features

Verify Citations: Check if a paper with specific details actually exists across multiple databases
Find Verified Papers: Search for real papers on a topic and get only verified citations from CrossRef, OpenAlex, and PubMed
Multi-Database Coverage: Cross-references results across academic databases for maximum reliability
Source Selection: Search all databases or target specific sources (CrossRef, OpenAlex, PubMed)
Citation Formatting: Returns properly formatted citations with DOIs

How It Works

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

Without this MCP: The assistant might cite "According to Smith et al. (2023) in Nature..." referencing a paper that doesn't exist
With this MCP: The assistant uses verifyCitation first, which searches across databases 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", or "pubmed"
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 databases findVerifiedPapers({ query: "CRISPR gene editing", limit: 5 }) // Search only PubMed for biomedical papers findVerifiedPapers({ query: "cancer immunotherapy", source: "pubmed", limit: 10 }) // Search with year filter findVerifiedPapers({ query: "machine learning", yearFrom: 2020, yearTo: 2024 })

Installation

Installing via Smithery

To install DOI Citation Verifier automatically via Smithery:

npx -y @smithery/cli install @tfscharff/doi-mcp

Manual Installation

Clone the repository
Install dependencies: npm install
Build the project: npm run build
Add to your MCP client configuration

Development

# Install dependencies npm install # Build npm run build # Development with watch mode npm run dev # Test with Smithery CLI npx @smithery/cli dev

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] "⚠ I cannot verify this citation - no matching publication found in CrossRef, OpenAlex, or PubMed databases. This citation may be incorrect."

API Sources

CrossRef API: 150+ million scholarly publications (https://api.crossref.org)
OpenAlex API: 250+ million scholarly works (https://api.openalex.org)
PubMed API: 35+ million biomedical and life sciences publications (https://api.ncbi.nlm.nih.gov/lit/ctxp)
DOI Resolution: DOI.org API (https://doi.org)

License

MIT

Contributing

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

DOI Citation Verifier