ClinicalTrials.gov MCP Server
An MCP server for the ClinicalTrials.gov registry: search across 600K studies, NCT records, results and trial matching
- 100 ★ on the repository
- Last commit
- Apache-2.0
Minimal access
Why this level
- Tools only read the public ClinicalTrials.gov registry and requests go to an external API
Install
- Works in
In your terminal, with SkillFoxx CLI
npx skillfoxx add mcp/clinicaltrials-gov-mcp-serverDetects the agents on your machine, shows the access level and pins the version.
Other ways to install
Access and checks
How we reviewMinimal accessThe tool runs nothing and makes no network calls.
- Tools only read the public ClinicalTrials.gov registry and requests go to an external API
This is third-party code. Review the repository files before installing.
What it does
The server works with the public API of the ClinicalTrials.gov clinical study registry of the US National Library of Medicine. Seven tools search studies by full-text and field queries (condition, intervention, location, sponsor) with status and phase filters, fetch a full record by NCT number and return posted results: outcomes, adverse events, participant flow. `clinicaltrials_get_study_count` quickly counts a selection without loading data, and two field tools suggest valid values and names. `clinicaltrials_find_eligible` matches a patient age, sex and condition to recruiting trials but does not check inclusion and exclusion criteria. There is also a resource by NCT, a landscape analysis prompt and the `clinicaltrialsgov-guide` skill.
Who it is for. Medical analysts and researchers who need the agent for trial reviews by disease, drug or country.
Good fit when
- The number of phase 3 trials recruiting patients with a given diagnosis must be estimated
- A full protocol record is needed by NCT number with the site list capped
- A review needs posted outcomes and adverse events of completed studies
- Recruiting trials near home are matched to a patient by age and condition
Not a fit when
- A medical decision is needed: the server searches registry data and gives no clinical assessment
- Exact inclusion criteria checking is required: `clinicaltrials_find_eligible` does not compare them
- Trials outside ClinicalTrials.gov are sought: the server reads no other registries
Example request
How many recruiting phase 3 trials for type 2 diabetes are running in Germany, and show the five latest with NCT numbersMCP
- Transport
- stdio, http
- Authentication
- not required
Environment variables
MCP_TRANSPORT_TYPE- Transport: `stdio` or `http`, `stdio` by default.
MCP_AUTH_MODE- HTTP auth mode: `none`, `jwt` or `oauth`.
Limitations
The server runs through `npx` or `bunx`, with STDIO and Streamable HTTP available and no required setup. All requests go to the ClinicalTrials.gov API, so its limits apply and a call is capped at a 50-second budget with retries. Trial matching (`clinicaltrials_find_eligible`) is indicative and does not check inclusion criteria. Registry data is filled in by sponsors, so it can be incomplete or outdated. HTTP auth is off by default, so set `MCP_AUTH_MODE` when exposing it.
How to disable. Remove the `clinicaltrialsgov-mcp-server` entry from `mcpServers` in the client config or stop the container if it ran in Docker.
FAQ
How do I connect the server to Claude Desktop?
An `mcpServers` entry with the `npx` command and the arguments `-y clinicaltrialsgov-mcp-server@latest`. A `bunx` variant exists for Bun.
Are API keys needed?
No. All settings are optional and the server uses the public ClinicalTrials.gov API with defaults.
Is there a public instance?
Yes, the README lists `https://clinicaltrials.caseyjhand.com/mcp`, but it belongs to the author, so running your own is wiser for real work.
Does matching check inclusion criteria?
No, `clinicaltrials_find_eligible` matches demographics and condition only, so check inclusion and exclusion criteria by hand.
What license applies?
Apache-2.0.
Discussion
No questions or reviews yet.
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