Openalex MCP Server

@cyanheads/openalex-mcp-server Access the OpenAlex academic research catalog — 270M+ publications — via MCP. STDIO or Streamable HTTP. 5 Tools • 2 Prompts

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

Overview

Scholarly catalog data from OpenAlex — 270M+ works, 90M+ authors, 100K+ sources, plus institutions, topics, keywords, publishers, funders, and awards. Search, filter, and aggregate across all nine entity types, resolve ambiguous names to canonical IDs, and walk the citation graph one hop at a time.

Tools

Prompts

The server also publishes an agent skill, openalex-guide (skill://openalex-guide/SKILL.md, source in skills/openalex-guide/): which filter key answers the question, how to read group_by counts, where each ID type comes from, and how to pin an author without picking a namesake. It ships in the npm package, the Docker image, the .mcpb bundle, and plugin installs.

Capability reference

openalex_search_entities tool

• Retrieve a single entity by id: an OpenAlex ID, DOI, ORCID, ROR, PMID, ISSN, or PMCID, bare or as a URL (OpenAlex record-page and API URLs such as https://openalex.org/works/W2741809807 included), or a keyword by its slug or URL. Under entity_type: "funders", a Crossref Funder Registry DOI (10.13039/…) also resolves
• id takes precedence: search parameters passed alongside it are dropped, and the response names which ones
• Lookups by ID are unbilled, except a keyword slug or URL, an id with characters past the identifier (W2741809807#x still returns W2741809807), and a funder DOI, which each bill as one list call
• Fails before any request as id_type_mismatch (an OpenAlex ID of another entity type) or id_dot_segment (a . or .. path segment); a ?, #, \, tab, or line break inside an identifier is percent-encoded, so SICI DOIs ending in # resolve
• A PMCID resolves nothing (OpenAlex indexes none); use the work's PMID or DOI
• entity_type: "awards" reaches grants (G… IDs), which openalex_resolve_name does not look up since OpenAlex has no award autocomplete
• Keyword search (boolean operators, quoted phrases, wildcards, fuzzy match) plus exact and semantic search modes — semantic ranks a query-dependent candidate set at ~1 req/sec (up to 50 per page), and its meta.count reports the candidate count rather than a match total
• filters accepts a record object or an unambiguous native string ("issn:0920-8542"), including through the filter alias. Conversion is disclosed in notice; commas outside paired double quotes separate clauses, and the first colon separates a key from its value, preserving DOI/URL colons and quoted comma phrases. Exact duplicate keys, bare fragments, and unmatched quotes are rejected with record-form recovery guidance. A record holds one value per key; distinct aliases of the same upstream field still AND together. Set OPENALEX_FILTER_STRING_INPUT=false to require record objects. Native strings apply only to this tool's filters, with the record form remaining the advertised schema
• Filter values sent unquoted must have paired double quotes on all four filter-taking tools (unmatched_quote_in_filter_value); citation filters are checked before the seed lookup. Balanced search phrases such as "graph neural" networks remain valid, including .search.exact. A value sent double-quoted still cannot contain its own interior double quote (quote_in_filter_value)
• Rich filter syntax: AND across fields, OR within a field (|), AND within a field (+), NOT (!), ranges, comparisons
• One value cannot mix | with an AND (a +, or a space between IDs or codes): OpenAlex would silently drop the AND-ed alternatives, so DE|FR+US and authorships.author.id: A1 A2|A3 fail as mixed_and_or_in_filter_value before any request. Put the AND in a second key instead (institutions.country_code: US beside authorships.institutions.country_code: DE|FR on works)
• Fields OpenAlex matches as whole text (display_name, awards.funder_display_name, awards.funder_award_id, geo.city, geo.region, raw_affiliation_strings, block_key, biblio fields) are sent double-quoted, so a value with spaces or commas matches as one phrase (awards.funder_display_name: National Science Foundation). ! and | still work (geo.city: New York|Boston); + cannot AND it with another value
• A comma is allowed in .search values and whole-text fields; anywhere else it fails as comma_in_filter_value (use | for OR)
• + is a literal character in .search values, DOIs, dates, URLs, exactly matched names (C++, Erasmus+), biblio fields (issue 1+2), and awards.funder_award_id
• A double quote inside a value sent quoted fails as quote_in_filter_value
• Country and language values are converted to the codes OpenAlex stores, in every tool that takes filters:
• Country fields (keys ending in country_code, country_codes, or countries): ISO alpha-3 codes, numeric codes, and English names (ISO's or OpenAlex's own facet labels, such as Ivory Coast) become alpha-2 (DEU, 276, Germany → DE; UK → GB). A value that cannot be a country (Germanyy, 999, DE US) fails as invalid_country_code before any request
• language: ISO 639-2 codes and English names become ISO 639-1 (eng, English → en; Cebuano → ceb)
• Each |/+ segment converts on its own (South Korea|Japan → KR|JP); anything else (null, XK, zh-cn, the countries/DEU path form) is sent as given
• select returns a curated per-entity-type default unless overridden, or ["*"] for the full record; invalid field names error with the valid set. On works, author_list returns each author in authorship order as {id, display_name, orcid} — about a tenth the size of authorships, which adds institutions and affiliations — and is never part of the default or ["*"]
• Cursor pagination for keyword and exact search, up to 100 results per page (default 25); semantic search walks its candidates with page (1-based) instead, up to 50 per page, and mixing either knob with the wrong search_mode is rejected before the upstream call
• sample (up to 10,000) plus a deterministic seed for reproducible random sampling; keyword and exact modes only, and never alongside sort or cursor — OpenAlex does not sample a semantic search and refuses a sorted sample, so those combinations are rejected before the upstream call. per_page defaults to min(sample, 100), so a sample of 100 or fewer returns whole in one call; a larger one is walked with page and a seed (sample_page_without_seed without one), up to record 10,000 (sample_page_too_deep past it)
• A page is per_page records, whole, and an id lookup returns every selected array whole; slice: {field, offset, limit} on an id lookup pages one array by count (limit default 50, clamped to 5,000). A response over 8,000,000 bytes on either surface (structuredContent, or content[] text) fails as response_too_large and names a per_page or slice.limit that fits, or a narrower select
• A list record carrying exactly 100 authorships or author_list entries is flagged as possibly capped, with an id + slice call to retrieve more stored authors. Singleton lookups and snapshots retain at most 5,000 authorships per work; at that ceiling both author fields remain possibly capped on every slice. total counts stored entries rather than a complete byline, and next becomes null when those entries are exhausted. Another OpenAlex fetch or snapshot cannot recover authors beyond the storage ceiling
• Oversized positive integers clamp to their cap, with requested/applied sizes in notice, a log, and a counter: per_page above 100 (200 on analysis, 50 under semantic search), slice.limit above 5,000, and sample above 10,000. Set OPENALEX_CLAMP_PER_PAGE=false to reject each over its cap instead. Zero, negatives, and fractions always reject. An id ignores page size
• display_name is nullable for untitled records; every call reports OpenAlex daily-budget cost and remaining balance

openalex_analyze_trends tool

• Group any supported field for trend, distribution, or comparative analysis; combine with filters to scope the population before aggregation
• Up to 200 groups per page (default). Without a cursor, order: "count" (default) returns the top-N by count with no further pages; order: "key" enumerates distinct values key-ascending with cursor pagination. Boolean fields keep count order even with "key" and do not support cursor pagination. A supplied cursor selects key order even when order is omitted or "count". OpenAlex can wrap a key-ordered walk to earlier groups: stop when a page's first key repeats an earlier key, or when a page is short or empty, even if next_cursor is still present
• `includ