io.github.SMABoundless/crossref

Official

by SMABoundless · Python

Search and retrieve scholarly metadata from the Crossref REST API

Search and retrieve scholarly metadata from Crossref REST API.

CrossRef MCP Server

An MCP (Model Context Protocol) server for searching and retrieving scholarly metadata from the CrossRef REST API — 150M+ records across all publishers and disciplines.

Built with FastMCP. No API key required.

Tools

Tool	Description
`crossref_search`	Search works by keyword with filtering by year, type, and sort options
`crossref_title_search`	Search specifically by title for more precise matching
`crossref_author_search`	Search for works by a specific author, optionally combined with keywords
`crossref_doi_lookup`	Retrieve full metadata for a work by DOI
`crossref_journal_search`	Search for journals by name
`crossref_journal_works`	Get works published in a specific journal by ISSN
`crossref_funder_search`	Search for funding organizations
`crossref_references`	Get the reference list cited by a specific work
`crossref_export_ris`	Export recent results as RIS (for Zotero, EndNote, etc.)
`crossref_export_bibtex`	Export recent results as BibTeX

Setup

1. Install

bash

cd crossref-mcp-server
python3 -m venv venv
source venv/bin/activate
pip install -r requirements.txt

2. Configure environment (optional)

CrossRef doesn't require an API key, but setting a mailto address gives you access to their faster "polite" API pool:

bash

cp .env.example .env
# Edit .env with your email address

3. Add to Claude Desktop

Add this to your claude_desktop_config.json:

json

{
  "mcpServers": {
    "crossref": {
      "command": "/path/to/crossref-mcp-server/venv/bin/python",
      "args": ["/path/to/crossref-mcp-server/server.py"],
      "env": {
        "CROSSREF_MAILTO": "your.email@example.com"
      }
    }
  }
}

Or if using Claude Code CLI:

bash

claude mcp add crossref \
  /path/to/crossref-mcp-server/venv/bin/python \
  /path/to/crossref-mcp-server/server.py \
  -e CROSSREF_MAILTO=your.email@example.com

Usage examples

Once connected, you can ask Claude things like:

"Search CrossRef for recent papers on transformer architectures"
"Find works by Jane Smith on educational psychology from 2020-2024"
"Look up the metadata for DOI 10.1038/nature14539"
"Search for journals about machine learning"
"Get the reference list for this paper and export as RIS for Zotero"

License

MIT

Install

Configuration

Environment variables

CROSSREF_MAILTO

Your email for Crossref polite pool (better rate limits, no key needed)

claude_desktop_config.json

{
  "mcpServers": {
    "crossref": {
      "command": "uvx",
      "args": [
        "crossref-mcp-server"
      ],
      "env": {
        "CROSSREF_MAILTO": "<YOUR_CROSSREF_MAILTO>"
      }
    }
  }
}