Ensembl MCP Server

@cyanheads/ensembl-mcp-server Look up genes, fetch sequences, predict variant consequences, find orthologs, and retrieve cross-database xrefs from Ensembl REST via MCP. STDIO or Streamable HTTP. Its 8 documented tools cluster into ensembl, errors.

People connecting database tools to Claude, Cursor, VS Code, or another MCP client. The project is written in TypeScript.

VERIFIED ACTIVE

LAST COMMIT 2026-08-22 · ★ 2 · #63 OF 151 MAINTAINED DATABASE · VERIFIED 2026-08-25

Apache-2.0 · TypeScript servers · how we verify → /methodology

01 · Install Ensembl MCP Server

before you install - you'll need

Set MCP_TRANSPORT_TYPE, MCP_LOG_LEVEL before connecting.

Claude Code

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

Claude Desktop / Cursor / VS Code - add to config

{
  "mcpServers": {
    "cyanheads-ensembl-mcp-server": {
      "url": "https://ensembl.caseyjhand.com/mcp"
    }
  }
}

Same JSON for Cursor. For VS Code, rename the top-level key from `mcpServers` to `servers`.

Using another client? Same JSON, different key

Claude Desktop · mcpServers

Cursor · mcpServers

VS Code · servers

Windsurf · mcpServers

Zed · context_servers

Cline · mcpServers

Roo Code · mcpServers

Continue · mcpServers

LibreChat · mcpServers

Gemini CLI · mcpServers

Codex CLI · mcp_servers

Full setup guides: every client.

02 · Evidence

https://ensembl.caseyjhand.com/mcp

transport: streamable-http

endpoint alive - responded to MCP initialize · probed 2026-08-25

Security posture

What to check before giving this server access to your agent - from the registry, GitHub, and our own probes. We don't score safety; we show what's verifiable.

runs as local process (stdio) - runs on your machine with your user's permissions · remote - your agent's requests go to ensembl.caseyjhand.com

endpoint auth accepted our unauthenticated MCP initialize - no credentials needed to connect

license Apache-2.0 - declared in the repository

npm package @cyanheads/ensembl-mcp-server - published under the repo owner's npm scope (@cyanheads)

registry namespace io.github.cyanheads is GitHub-verified and matches the repo owner

03 · What Ensembl MCP Server can do

Prose above is summarized from the project's README and registry record - no invented capabilities.

What you can build

With this server connected, an agent can list species supported by Ensembl with display name, common name, assembly, taxon ID, and division, resolve a gene by symbol + species or by stable ID to its Ensembl ID, genomic location, biotype, and transcript list, fetch the DNA, cDNA, CDS, or protein sequence for a gene, transcript, protein, or genomic region, and find genomic features (genes, transcripts, variants, regulatory elements, exons) overlapping a chromosomal region.

Capability map

Tools grouped from the project's README - what Ensembl MCP Server lets an agent do.

Ensembl

7 tools - e.g. List species supported by Ensembl with display name, common name, assembly, taxon ID, and division; Resolve a gene by symbol + species or by stable ID to its Ensembl ID, genomic location, biotype, and…

ensembl_list_species · ensembl_lookup_gene · ensembl_get_sequence · ensembl_query_region · ensembl_predict_variant · ensembl_get_homology…

Errors

1 tool - e.g. not_found (symbol or ID not in Ensembl), invalid_species (call ensembl_list_species to discover valid names)

Errors

Latest releases

v0.4.3 · 2026-08-22

MCP SDK v2 maintenance · MCP 2026-07-28 support rejects undeclared top-level inputs and advertises error envelopes, JSON Schema 2020-12, and client-visible logging. · Public cache hints and an explicit stateless HTTP…

v0.4.2 · 2026-07-09

output caps and error recovery hints · Result-shaping caps for high-cardinality VEP and homology output, plus recovery hints on every declared error. · Added: · ensembl_predict_variant: max_transcript_consequences…

v0.4.1 · 2026-07-09

get-sequence expand/region fixes, mcp-ts-core 0.10.14 · ensembl_get_sequence stable-ID lookups now forward expansion params, · and region mode accepts a bare chr:start-end id. Framework maintenance · adds a Bun…

04 · Who maintains Ensembl MCP Server

ensembl-mcp-server is maintained by cyanheads. We track 125 MCP servers from cyanheads - 124 actively maintained, 1,730 combined GitHub stars, oldest repo from Dec 2024. Full record: all servers from cyanheads.

  1. mcp-ts-core Agent-native TypeScript framework for building MCP servers with declarative definitions. ★ 148
  2. obsidian-mcp-server Read, write, search, and surgically edit Obsidian notes, tags, and frontmatter via MCP. ★ 668
  3. git-mcp-server Comprehensive Git MCP server enabling native git tools including clone, commit, worktree, & more. ★ 235
  4. pubmed-mcp-server Search PubMed/Europe PMC, fetch articles and full text (PMC/EPMC/Unpaywall), citations, MeSH terms. ★ 137
  5. clinicaltrialsgov-mcp-server Search ClinicalTrials.gov - find studies, retrieve results, match patients to eligible trials. ★ 90
  6. mcp-ts-template TypeScript template for building MCP servers with declarative tooling, observability, and auth. ★ 148

05 · Facts

category
database - ranked #63 of 151 actively-maintained database servers as of 2026-08-25.
release cadence
10+ releases in the last 90 days (latest 2026-08-22)
registry
io.github.cyanheads/ensembl-mcp-server (active, first published 2026-06-05 · 11 versions)
packages
npm:@cyanheads/ensembl-mcp-server · npm:@cyanheads/ensembl-mcp-server

06 · Ensembl MCP Server FAQ

Is Ensembl MCP Server still maintained?

Yes - as of 2026-08-25, its last commit was 2026-08-22 and it shipped 10+ releases in the last 90 days. We re-verify nightly.

What can Ensembl MCP Server do?

With this server connected, an agent can list species supported by Ensembl with display name, common name, assembly, taxon ID, and division, resolve a gene by symbol + species or by stable ID to its Ensembl ID, genomic location, biotype, and transcript list, fetch the DNA, cDNA, CDS, or protein sequence for a gene, transcript, protein, or genomic region, and find genomic features (genes, transcripts, variants, regulatory elements, exons) overlapping a chromosomal region.

How do I install Ensembl MCP Server?

Run `npx -y @cyanheads/ensembl-mcp-server`. The README documents 2 environment variables (MCP_TRANSPORT_TYPE, MCP_LOG_LEVEL) to set first. Set MCP_TRANSPORT_TYPE, MCP_LOG_LEVEL before connecting. You can also paste the ready-made client config above.

Does Ensembl MCP Server require authentication?

No - the endpoint accepted our unauthenticated MCP initialize when probed on 2026-08-25; you can connect without credentials.

07 · Alternatives to Ensembl MCP Server