Overview

bioRxiv and medRxiv preprints, metadata and full text. Search by keyword and author, browse a date interval (optionally by subject), fetch any preprint by DOI, and see which preprints went on to journal publication.

Tools

Capability reference

biorxiv_get_preprint _tool

• Takes DOIs bare or pasted (https://doi.org/…, doi:…, a biorxiv.org/medrxiv.org article URL, a vN or .full suffix), scoped to biorxiv, medrxiv, or both (default both)
• Accepts up to 200 entries and looks up the first 10 distinct DOIs; the rest come back in unprocessed[] to pass in another call. A repeated DOI is looked up once, and every list keeps input order
• Each preprint returns its full revision history in revisions[] — title, authors, category, license, awards, jatsxmlUrl, publishedJournalDoi once accepted, and the server it was found on (biorxiv or medrxiv, ready to pass back as server). Funder names are omitted because the upstream API misattributes them
• The abstract sits on the latest revision only: the upstream API keeps one abstract per preprint. An earlier revision's own abstract is on its article page, through biorxiv_get_fulltext with version
• A DOI that fails lands in failed[] with a reason (not_found, invalid_doi_format, upstream_unavailable, rate_limited) and a retryable flag; not_found only when every attempted server answered

biorxiv_list_recent _tool

• Takes a start_date/end_date interval, server (default both), and optional category (a value from biorxiv_list_categories) and bioRxiv-only funder (a ROR ID) filters; a filter that cannot be applied raises invalid_category or invalid_funder
• Pages of 30 advance with an integer cursor, tracked per server ({ biorxiv: { cursor, total, newPreprints }, medrxiv: { cursor, total, newPreprints } }); a cursor past the last page is marked exhausted: true, and a server that did not answer is named in failed[]
• Rows are revisions: total counts every version posted in the interval, while newPreprints counts the preprints whose first version posted in it, as the API reports it (absent when the API sends no count)
• Abstracts are omitted by default; include_abstract: true adds them. Each is the preprint's latest-revision abstract, even on a row for an earlier revision

biorxiv_search_preprints _tool

• Takes query and/or author, optional date_from/date_to and server (default both); up to 100 results per page (default 25; a larger limit returns 100 with a notice), paged with cursor_mark
• EuropePMC ranks the matches (it indexes new preprints within 1–2 days of posting) and the bioRxiv/medRxiv API enriches them with the same fields as biorxiv_get_preprint; a record left with EuropePMC metadata only carries enriched: false and an enrichment_error (service_error, rate_limited, not_found), with partial_results set
• Abstracts are included by default; include_abstract: false drops them for a response about a third the size

biorxiv_get_published_version _tool

• Takes one DOI and server (default both): a preprint DOI (10.1101/, 10.64898/), or a journal article's DOI, which resolves to the preprint it was posted as (10.1016/j.cell.2020.01.001 → 10.1101/614172); 10.64898/ DOIs resolve through the preprint's own journal DOI
• Returns the preprint DOI, journal DOI, journal name, published date, corresponding-author institution, and the server that answered; if no server answers it raises a retryable upstream_unavailable or rate_limited, never doi_not_found
• Cold Spring Harbor Laboratory Press journal DOIs (10.1101/gr.…, gad.…, lm.…) share the preprint prefix and cannot be resolved by DOI

biorxiv_list_published_versions _tool

• Takes a start_date/end_date interval of journal publication dates and server (default both); each row matches the record biorxiv_get_published_version returns, and may be a preprint posted years earlier
• Returns limit rows per server (default 25, up to the API's 100-row page) from an integer cursor, continued at each server's nextCursor; a cursor past the last row is marked exhausted: true, and a server that did not answer is named in failed[]
• Optional publisher, a journal DOI prefix (10.7554 for eLife), lists only the bioRxiv preprints published under it; server: "both" queries bioRxiv alone, and server: "medrxiv" or a prefix the API does not recognize raises invalid_publisher. These rows carry no journal name, authors, or abstract
• Abstracts are omitted by default; include_abstract: true adds them

biorxiv_get_fulltext _tool

• Takes a DOI, server (default both), and an optional version (or a vN suffix; the two must agree, and a version the preprint lacks raises version_not_found); returns Markdown extracted from the rendered HTML article page, naming the answering server
• Table cells are not on the page: each table keeps its caption, and omittedTables names it with the URL that serves its cells
• Pages via offset/limit characters (default 20,000), reporting totalChars, remainingChars, hasMore, and wordCount; PDF-only preprints and blocked pages raise fulltext_unavailable, routing to biorxiv_get_preprint

biorxiv_list_categories _tool

• No API call — a static list of 25 bioRxiv and 51 medRxiv categories, limited to the ones the listing API filters on
• Use it to pick a category for biorxiv_list_recent

Features

Built on @cyanheads/mcp-ts-core: stdio and Streamable HTTP transports, pluggable auth (none / jwt / oauth), swappable storage (in-memory, filesystem, Supabase, Cloudflare KV/R2/D1), structured logging with optional OpenTelemetry tracing.

bioRxiv-specific:

• BiorxivApiService wraps api.biorxiv.org (details, publications, and crosswalk endpoints) and EuropePmcService wraps EuropePMC search, both with retry and exponential backoff
• BiorxivFullTextService extracts Markdown from the article pages on www.biorxiv.org / www.medrxiv.org
• Every upstream retry ladder runs on what is left of the tool call's one 50 s budget, so a hung origin ends before a client's 60 s request timeout — in a classified, retryable error, or, when the step that hung is optional, in a result that says what is missing
• Queries biorxiv and medrxiv in parallel when server="both", each result naming the server that answered; a lookup by DOI stops waiting once the server holding that DOI answers
• Polite User-Agent header including a mailto address (BIORXIV_MAILTO env var) per Cold Spring Harbor Lab API guidelines
• Pairs with pubmed-mcp-server (post-publication), openalex-mcp-server (citation analytics), and crossref-mcp-server (DOI metadata)

Agent-friendly output:

• Graceful partial failure — per-DOI and per-server failures land in failed[] with a typed reason and retryable flag instead of aborting the call
• Rate-limit transparency — a 429 surfaces as reason: "rate_limited" with the parsed retryAfter wait, distinct from upstream_unavailable
• Typed enrichment status — biorxiv_search_preprints results carry enriched plus a typed enrichment_error (service_error / rate_limited / not_found)
• Clean titles and abstracts — export markup and symbol placeholders ({beta}, [≥]) are resolved to plain text

Getting started

Connect to the hosted instance, no install:

claude mcp add --transport http biorxiv-mcp-server https://biorxiv.caseyjhand.com/mcp

Or run it locally:

claude mcp add biorxiv-mcp-server -- npx -y @cyanheads/biorxiv-mcp-server

For other clients, add this to the MCP config file:

{
  "mcpServers": {
    "biorxiv-mcp-server": {
      "command": "npx",
      "args": ["-y", "@cyanheads/biorxiv-mcp-server"]
    }
  }
}

A contact email in BIORXIV_MAILTO (-e [email protected], or an env entry) identifies your requests in the User-Agent header, as the Cold Spring Harbor Lab API guidelines ask. For Docker or a source build, see Running the server.

Configuration

All configuration is validated at startup via Zod schemas in src/config/server-config.ts.

See .env.example for the full list of optional overrides.

Running the server

Local development

Requires Bun v1.4.0 or higher (or Node.js v24+).

• Clone and install:

  git clone https://github.com/cyanheads/biorxiv-mcp-server.git
  cd biorxiv-mcp-server && bun install
  cp .env.example .env   # optionally set BIORXIV_MAILTO
  

• Build and run:

  # One-time build
  bun run rebuild
  
  # Run the built server
  bun run start:stdio
  # or
  bun run start:http
  

• Run checks and tests:

  bun run devcheck   # Lint, format, typecheck, security
  bun run test       # Vitest test suite
  bun run lint:mcp   # Validate MCP definitions against spec
  

Docker

docker run --rm -e [email protected] -p 3010:3010 ghcr.io/cyanheads/biorxiv-mcp-server:latest

The image defaults to HTTP transport, stateless session mode, and logs to /var/log/biorxiv-mcp-server; the server listens at http://localhost:3010/mcp. To run it over stdio from an MCP client, use "command": "docker" with "args": ["run", "-i", "--rm", "-e", "MCP_TRANSPORT_TYPE=stdio", "ghcr.io/cyanheads/biorxiv-mcp-server:latest"]. To build locally, docker build -t biorxiv-mcp-server .; OpenTelemetry peer dependencies are installed by default — build with --build-arg OTEL_ENABLED=false to omit them.

Project structure

Development guide

See CLAUDE.md for development guidelines and architectural rules. The short version:

• Handlers throw, framework catches — no try/catch in tool logic
• Use ctx.log for request-scoped logging, ctx.state for tenant-scoped storage
• Register new tools via the barrel in src/mcp-server/tools/definitions/index.ts
• Wrap external API calls: validate raw → normalize to domain type → return output schema; never fabricate missing fields

Contributing

Issues are welcome. Run checks and tests before submitting:

bun run devcheck
bun run test

License

Apache-2.0 — see LICENSE for details.