What it is
Eleven tools over NCBI's E-utilities, the PMC ID Converter, Europe PMC and Unpaywall, plus a pubmed://database/info resource and a research_plan prompt. It runs over stdio, as a Streamable HTTP server, or on Cloudflare Workers from the same codebase.
Requirements
Nothing to sign up for — PubMed and Europe PMC are public, and MCP_AUTH_MODE defaults to none. An NCBI_API_KEY is optional and raises the rate limit from 3 req/s to 10 req/s; NCBI_ADMIN_EMAIL is the contact address NCBI asks you to send along. Setting UNPAYWALL_EMAIL is what turns on the Unpaywall stage of the full-text chain. Run it with npx from @cyanheads/pubmed-mcp-server, from the ghcr.io/cyanheads/pubmed-mcp-server image, or against the author's public instance at https://pubmed.caseyjhand.com/mcp; building from the repository wants Bun v1.3.2 or higher.
Setup effort
One command — npx -y @cyanheads/pubmed-mcp-server@latest