ClinicalTrials.gov MCP Server

A Model Context Protocol (MCP) server that provides access to the ClinicalTrials.gov API v2, enabling AI assistants to search and retrieve clinical trial data.

Features

• Search clinical trials with filters (status, phase, condition, intervention, sponsor, study type)

• Get detailed study information by NCT ID

• Retrieve field metadata for available data fields

• Get search areas and available filters

• Query dataset statistics

• API version information

Related MCP server: Clinical Trials MCP Server

Installation

npm install

Building

npm run build

Running

Local Development (HTTP API)

npm start

The HTTP API will be available at:

• Health check: http://localhost:3000/health

• Tools list: http://localhost:3000/tools

• Tool endpoints: http://localhost:3000/tools/{tool_name}

Local Development (MCP stdio)

For local MCP client integration via stdio:

npm run start:stdio

Deployment

Vercel (HTTP API)

The server is deployed on Vercel at:

• Production: https://clinicaltrials-mcp-server-three.vercel.app

• Health check: https://clinicaltrials-mcp-server-three.vercel.app/health

• Tools list: https://clinicaltrials-mcp-server-three.vercel.app/tools

MCP Configuration

For HTTP API (Vercel)

Configure your MCP client to use the HTTP endpoints:

{
  "mcpServers": {
    "clinicaltrials": {
      "url": "https://clinicaltrials-mcp-server-three.vercel.app",
      "transport": "http"
    }
  }
}

For Local stdio

Add this server to your MCP client configuration:

{
  "mcpServers": {
    "clinicaltrials": {
      "command": "node",
      "args": ["/path/to/clinicaltrials-mcp-server/dist/server.js"]
    }
  }
}

Available Tools

search_studies

Search clinical trials with filters.

Parameters:

• queryTerm (string, optional): Full-text search term

• status (string, optional): Trial status (RECRUITING, COMPLETED, ACTIVE_NOT_RECRUITING, etc.)

• phase (string, optional): Clinical trial phase (PHASE1, PHASE2, PHASE3, etc.)

• condition (string, optional): Medical condition or disease

• intervention (string, optional): Intervention or treatment type

• leadSponsor (string, optional): Lead sponsor name

• studyType (string, optional): Study type (INTERVENTIONAL, OBSERVATIONAL, EXPANDED_ACCESS)

• pageSize (number, optional): Results per page (1-1000, default: 50)

• pageToken (string, optional): Pagination token for next page

Example:

{
  "queryTerm": "diabetes",
  "status": "RECRUITING",
  "phase": "PHASE2",
  "pageSize": 10
}

get_study

Get detailed information about a specific clinical trial by NCT ID.

Parameters:

• nctId (string, required): ClinicalTrials.gov identifier (e.g., "NCT04000009")

Example:

{
  "nctId": "NCT04000009"
}

get_study_fields

Get metadata about all available data fields in ClinicalTrials.gov study records.

Parameters: None

get_search_areas

Get available search areas and filters for querying clinical trials.

Parameters: None

get_dataset_stats

Get statistics about the ClinicalTrials.gov database.

Parameters:

• queryTerm (string, optional): Query term to filter statistics

get_api_version

Get the ClinicalTrials.gov API version information.

Parameters: None

API Reference

This server uses the ClinicalTrials.gov Data API v2, which is a public, unauthenticated REST API.

Base URL: https://clinicaltrials.gov/api/v2

Project Structure

clinicaltrials-mcp-server/
├── src/
│   ├── api-client.ts          # ClinicalTrials.gov API client
│   ├── server.ts              # MCP server setup
│   ├── index.ts               # Main entry point
│   ├── types/
│   │   └── api.ts             # TypeScript type definitions
│   └── tools/
│       ├── search-studies.ts
│       ├── get-study.ts
│       ├── get-study-fields.ts
│       ├── get-search-areas.ts
│       ├── get-dataset-stats.ts
│       └── get-api-version.ts
├── dist/                      # Compiled JavaScript
├── package.json
├── tsconfig.json
└── README.md

Development

This project uses:

• TypeScript for type safety

• @modelcontextprotocol/sdk for MCP server implementation

• Node.js runtime

License

ISC