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Ebi Ols

EBI Ontology Lookup Service — 250+ biomedical ontologies

Install Ebi Ols

Pick your client, then add it in one click or paste the config.

STDIONode.js
~/Library/Application Support/Claude/claude_desktop_config.json
claude_desktop_config.json
{
  "mcpServers": {
    "ebi-ols": {
      "command": "npx",
      "args": [
        "-y",
        "@pipeworx/mcp-ebi-ols"
      ]
    }
  }
}

Settings → Developer → Edit Config, merge this into mcpServers, then fully quit and reopen Claude Desktop.

Automated check passed— started and listed 6 tools correctly (6d ago).

Overview

Tools6

What Ebi Ols lets your agent do. Expand a tool for its parameters.

Verified live~435 tokens of context

Security & health

What it can reach and how reliably it runs — from our own checks, not the maintainer’s claims.

ActiveLast checked 2d ago

Recent health check succeeded.

7/7 checks healthy over the last 46d

What it can do

From the 6 tools this server returned when we ran it.

Read-only tools · 6
Network at startup3 connections
Files written at startupNone
Install scriptsNone
npm provenanceSigned build
Package age155 days
Maintainers1

Observed 2026-10-17 in an isolated sandbox. A description of reach, not a security audit.

Supply-chain signal

No high-severity advisories surfaced by our automated scan.

Critical 0High 0Medium 0Low 0

Scanned 14d ago via OSV.dev · @pipeworx/mcp-ebi-ols (npm)

Adoption & maintenance

Factual signals from GitHub, npm, and our automated checks — not a rating.

npm downloads455Package downloads in the last 30 days.
Last commit27d agoMost recent push to the default branch.
Availability100%Our rolling endpoint + install checks that succeeded.
Install checkPassedOur sandbox started it and listed its tools.
Tools exposed6Callable tools this server registers over MCP.
Directory activity2 viewsConfig copies, upvotes, and views on AllMCPs.

From the project README

@pipeworx/ebi-ols

EBI Ontology Lookup Service (OLS) MCP — search and traverse ~250 biomedical ontologies (GO, EFO, MONDO, CL, ChEBI, HP, …). Keyless.

Part of Pipeworx — an MCP gateway connecting AI agents to 1855+ live data sources. This is an independent, unofficial integration — not affiliated with, endorsed by, or published by the upstream provider.

Tools

  • list_ontologies(size?, page?) — list all loaded ontologies
  • get_ontology(id) — ontology metadata (latest release, term count, …)
  • search(query, ontology?, type?, exact?, rows?) — full-text search across terms
  • get_term(ontology, iri|short_form|obo_id) — term details
  • term_ancestors(ontology, iri) — transitive parents
  • term_children(ontology, iri) — direct children

Data source

https://www.ebi.ac.uk/ols4/api/

Quick Start

Add to your MCP client (Claude Desktop, Cursor, Windsurf, etc.):

config.json
{
  "mcpServers": {
    "ebi-ols": {
      "url": "https://gateway.pipeworx.io/ebi-ols/mcp"
    }
  }
}

What this endpoint actually serves

tools/list at https://gateway.pipeworx.io/ebi-ols/mcp returns the tools in the table above plus the shared Pipeworx meta-tools — ask_pipeworx, discover_tools, search_within, remember/recall and the rest of the gateway-wide set. So the tool count you see is larger than this table: a single-pack endpoint currently lists roughly 30 shared tools alongside the pack's own. The connection's initialize response states its exact scope, and is the authoritative answer for a given day.

This is deliberate, not multiplexing by accident. The meta-tools are what let a scoped connection answer a question this pack does not cover — via ask_pipeworx, which routes across the whole catalog — without you adding a second MCP server. There is currently no way to mount a pack endpoint without them; if the extra schemas cost you more context than the routing is worth, connect to the full gateway once rather than to several pack endpoints.

Or connect to the full Pipeworx gateway to get every pack's tools listed directly, instead of just this one's:

config.json
{
  "mcpServers": {
    "pipeworx": {
      "url": "https://gateway.pipeworx.io/mcp"
    }
  }
}

Both URLs reach the same gateway and the same 1855+ data sources. The only difference is which pack's tools are listed directly; ask_pipeworx reaches all of them from either one.

No MCP client? Call it over HTTP

Terminal
curl -X POST https://gateway.pipeworx.io/v1/tools/list_ontologies \
  -H 'Content-Type: application/json' \
  -d '{"size":20,"page":0}'

No account needed for the first calls. Inspect any tool: GET https://gateway.pipeworx.io/v1/tools/list_ontologies. Find one: POST https://gateway.pipeworx.io/v1/tools/search_packs with {"query":"..."}.

Standalone (no gateway account)

This package also runs as a local stdio MCP server — no Pipeworx account, no gateway round-trip:

config.json
{
  "mcpServers": {
    "ebi-ols": {
      "command": "npx",
      "args": ["-y", "@pipeworx/mcp-ebi-ols"]
    }
  }
}

Or run it directly to confirm it starts:

Terminal
npx -y @pipeworx/mcp-ebi-ols

It speaks MCP over stdin/stdout and answers initialize/tools/list/tools/call for only this pack's tools — none of the shared meta-tools the gateway connection above adds. Same source, same tools, no ask_pipeworx routing.

Using with ask_pipeworx

Instead of calling tools directly, you can ask questions in plain English — this works on the pack endpoint above as well as on the full gateway:

Code
ask_pipeworx({ question: "your question about Ebi Ols data" })

The gateway picks the right tool and fills the arguments automatically.

More

License

MIT

Reviews

No reviews yet — be the first to share how it worked for you.

Frequently Asked Questions about Ebi Ols

Ebi Ols is an MCP server that provides access to the EMBL-EBI Ontology Lookup Service, covering approximately 250 biomedical ontologies such as GO, EFO, MONDO, CL, ChEBI, and HP. It supports ontology listing, metadata retrieval, full-text term search, term details, and ancestor or child traversal. Keyless access is available.

Use the `search` tool to perform full-text searches across ontology terms. You can optionally specify an ontology, result type, exact matching, and the number of returned rows.

Ebi Ols provides tools for listing ontologies, retrieving ontology metadata, searching terms, getting term details, finding transitive ancestors, and finding direct children. The tools are `list_ontologies`, `get_ontology`, `search`, `get_term`, `term_ancestors`, and `term_children`.

Connect an MCP client to `https://gateway.pipeworx.io/ebi-ols/mcp` to use the gateway-hosted server, or run `npx -y @pipeworx/mcp-ebi-ols` as a local stdio MCP server. The gateway endpoint includes shared Pipeworx meta-tools, while the standalone server exposes only Ebi Ols tools.

Yes, Ebi Ols can retrieve term relationships through `term_ancestors` and `term_children`. `term_ancestors` returns transitive parents, while `term_children` returns direct children for a specified ontology term IRI.

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