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io.github.SMABoundless/crossref

Official registry Search and web

Search and retrieve scholarly metadata from the Crossref REST API

Source code Documentation

Install

Add this to your client's MCP configuration (Claude Desktop: claude_desktop_config.json; Cursor: .cursor/mcp.json; VS Code and others use the same "mcpServers" shape).

PYPI package crossref-mcp-server
Claude Code 
claude mcp add crossref -e 'CROSSREF_MAILTO=<CROSSREF_MAILTO>' -- uvx crossref-mcp-server==1.0.0
JSON configuration (Claude Desktop, Cursor, VS Code) 
{
    "mcpServers": {
        "crossref": {
            "command": "uvx",
            "args": [
                "crossref-mcp-server==1.0.0"
            ],
            "env": {
                "CROSSREF_MAILTO": "<CROSSREF_MAILTO>"
            }
        }
    }
}

Environment variables

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

Documentation

From the project's README on GitHub, refreshed weekly. Links open on GitHub.

Contents
  1. CrossRef MCP Server
  2. Tools
  3. Setup
  4. Usage examples
  5. License

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

ToolDescription
crossref_searchSearch works by keyword with filtering by year, type, and sort options
crossref_title_searchSearch specifically by title for more precise matching
crossref_author_searchSearch for works by a specific author, optionally combined with keywords
crossref_doi_lookupRetrieve full metadata for a work by DOI
crossref_journal_searchSearch for journals by name
crossref_journal_worksGet works published in a specific journal by ISSN
crossref_funder_searchSearch for funding organizations
crossref_referencesGet the reference list cited by a specific work
crossref_export_risExport recent results as RIS (for Zotero, EndNote, etc.)
crossref_export_bibtexExport recent results as BibTeX

Setup

1. Install
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:

cp .env.example .env
# Edit .env with your email address
3. Add to Claude Desktop

Add this to your claude_desktop_config.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:

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

Frequently asked questions

What is io.github.SMABoundless/crossref?

Search and retrieve scholarly metadata from the Crossref REST API

How do I install io.github.SMABoundless/crossref?

It runs on your machine. In Claude Code: claude mcp add crossref -e 'CROSSREF_MAILTO=<CROSSREF_MAILTO>' -- uvx crossref-mcp-server==1.0.0. For other clients, paste the JSON configuration from this page into their MCP settings.

Does io.github.SMABoundless/crossref need an API key?

Its registry entry lists no required key or secret. Some features may still need an account with the service it connects to.

Is io.github.SMABoundless/crossref open source?

Yes. Its code is on GitHub under the MIT license.

Who maintains io.github.SMABoundless/crossref?

It is published by SMABoundless. AI.tn lists it but does not maintain or endorse it.

From the official MCP Registry. Listing is not an endorsement: review a server's code and permissions before giving it access to your data.