Crossref MCP Server

@cyanheads/crossref-mcp-server Resolve DOIs, search ~188M scholarly works, fetch references, and look up publishers via the Crossref REST API. STDIO or Streamable HTTP. 7 Tools • 1 Resource

Public Hosted Server: https://crossref.caseyjhand.com/mcp

Overview

Scholarly metadata from the Crossref REST API. Resolve DOIs to full metadata records, search across ~188 million scholarly works by free text or structured filters, fetch outgoing reference lists, and look up journals, funders, and publishers.

Tools

Resources

The skill is also served through the skill://{+path} template and ships as skills/crossref-guide/SKILL.md in the npm package, the Docker image, the .mcpb bundle, and plugin installs. The tools do not depend on it.

Capability reference

crossref_get_work tool

• DOI validated against the 10.NNNN/suffix regex before the upstream call, accepted either bare or wrapped in its resolver (https://doi.org/…, https://dx.doi.org/…, doi:…) and unwrapped before the lookup
• Returns title, authors with affiliations, abstract (when deposited), container/journal, publication date, work type, ISSN, license URLs, full-text link URLs, and funder acknowledgements
• containerTitles lists every container title the record deposits, in deposited order — a book chapter or proceedings paper often deposits its series and then its book or volume — beside containerTitle, which keeps the first; crossref_search_works returns both, and its container-title select name fills both
• Citation locators volume, issue, page, and articleNumber under the same names and on the same rendered line as crossref_search_works, plus isbn — each as deposited, omitted when absent
• memberId is the Crossref member that holds the DOI now — pass it to crossref_get_member for the publisher record. For a title transferred to another publisher it differs from the member the DOI's prefix names through crossref_get_prefix
• editors in the author entry shape, returned whole and never counted in authorCount
• Author list paged by offset/limit (default 25, up to 10,000 per call — a larger limit is clamped to 10,000 with a notice); authorCount reports the full deposited total and a nextOffset continues when authors remain — every other field is returned in full on every page
• updatedBy lists the corrections, retractions, expressions of concern, and new versions Crossref records against the work — notice DOI, type, source (publisher or retraction-watch, with its record ID), and date, entry for entry — and updateTo the works this record is a notice for; when updatedBy is present, notice names each update type with its sources. An absent updatedBy does not mean the work was never updated
• relations groups related identifiers (preprint ↔ published version, versions, reviews, supplements) by relation type, identifier type, and asserting party, returned whole; only Crossref-registered DOIs among them resolve through this tool
• A funder or affiliation asserted only through the ROR registry (no name deposited) carries ror in place of name, never as a blank entry
• Publication date is the first of published, published-print, published-online, and issued (this tool only) that names a value; a date component Crossref records as unknown is omitted, along with everything less precise below it
• Outgoing references are reported as a count (referencesCount) — entries come from crossref_get_references; incoming citation count (isReferencedByCount) is included, but citing works are not exposed by Crossref — use OpenAlex for citation graphs
• A DOI Crossref holds no record for returns doi_not_found naming the agency the DOI registry says holds it (registrationAgency — DataCite, JaLC, mEDRA, …), a Funder Registry pointer when Crossref registered it, or that no agency registered it at all

crossref_search_works tool

• Free-text query plus a structured filter object using Crossref's hyphenated keys (from-pub-date, type, funder, issn, has-abstract, license.url, etc.)
• Field-scoped parameters queryTitle, queryAuthor, queryContainerTitle, and queryBibliographic combine with query and with each other
• Sort by relevance, score, is-referenced-by-count, published, deposited, or other listed fields — the publication-date sorts page by offset only, since Crossref refuses them with a cursor. A cursor walk with a query term and no sort runs by relevance (sent as sort=score, without order) and can repeat or skip a record at a page boundary; sort: "created" walks without repeats. A filter-only walk runs in Crossref registration order
• fields narrows the payload to any of the 20 select names the summary projects — including the citation locators volume, issue, page, article-number, and ISSN, the update links updated-by and update-to, and member for memberId, which every work also carries when fields is omitted — and refuses any other name; DOI is always returned, and crossref_get_work carries the rest of the record
• Each work carries updatedBy (corrections, retractions, expressions of concern, new versions recorded against it) and updateTo (the works it is a notice for) in the entry shape and rendered line crossref_get_work uses, so a page of results can be screened for retractions without a call per DOI
• A blank or whitespace-only query term or filter value, and an empty sort or order, is read as omitted; when that leaves nothing to search by, the notice says the page is an unfiltered listing
• rows returns up to 250 works per call and authorLimit caps authors per work (default 25, up to 500); a larger value of either is clamped to its cap with a notice, which on an offset page also names the offset that continues after the records returned; authorCount reports the full deposited total — chain a cut work's DOI into crossref_get_work for the rest
• Offset paging is capped at offset + rows ≤ 10,000: a page that would pass it returns the rows that fit, with a notice naming the rows requested and applied, and an offset of 10,000 or more is refused (offset_too_large); cursor="*" starts deep paging via chained nextCursor tokens — cursor and offset cannot be combined
• A cursor walk ends on the page that omits nextCursor — an empty page never carries one; every empty page's notice names which of the three causes applies

crossref_get_references tool

• Takes the citing work's DOI bare or resolver-wrapped, the same forms crossref_get_work accepts
• Each reference carries its deposited citation string and, when Crossref has resolved it, a DOI for crossref_get_work, with doiAssertedBy saying whether the publisher deposited that DOI or Crossref matched it
• Structured parts as deposited: author, year, article title, journal title, the title of a cited book or volume (volumeTitle, which stands in as the title when there is no article title), series title, volume, issue, first page, edition, and ISSN
• Citation strings have formatting markup stripped and character references decoded; a bracketed span that isn't a recognized tag (a cited URL, a Miller index, a DOI fragment) is left exactly as deposited
• Paged by offset/limit (default 100, up to 2,500 per call — a larger limit is clamped to 2,500 with a notice); referenceCount is the full deposited total and nextOffset continues when more remain
• Coverage varies by publisher — pre-2000 works and non-participating publishers often have no indexed references
• Single-hop only; incoming citations are not available through Crossref — use OpenAlex for citation graphs
• A DOI Crossref holds no record for returns doi_not_found naming its registration agency (registrationAgency), or saying no agency registered it, the same way crossref_get_work does

crossref_search_journals tool

• include_works: true also returns a page of the journal's most recent works, drawn from every ISSN its record lists whichever one was passed — newest published first by works_offset, newest registered first on a works_cursor wal