Model Context Protocol (MCP) Server providing a robust, developer-friendly interface to the official ClinicalTrials.gov v2 API. Enables LLMs and AI agents to search, retrieve, and analyze clinical study data programmatically.

Built on the cyanheads/mcp-ts-template, this server follows a modular architecture with robust error handling, logging, and security features.

🚀 Core Capabilities: ClinicalTrials.gov Tools 🛠️

This server equips your AI with specialized tools to interact with the ClinicalTrials.gov database:

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Table of Contents

| Overview | Features | Installation | Configuration | Project Structure | Tools | Development & Testing | License

Overview

The ClinicalTrials.gov MCP Server acts as a bridge, allowing applications (MCP Clients) that understand the Model Context Protocol (MCP) – like advanced AI assistants (LLMs), IDE extensions, or custom research tools – to interact directly and efficiently with the official ClinicalTrials.gov database.

Instead of complex API integration or manual searches, your tools can leverage this server to:

• Automate clinical research workflows: Search for clinical trials, fetch detailed study metadata, and analyze trial characteristics programmatically.
• Gain research insights: Access comprehensive trial data including study protocols, eligibility criteria, outcomes, sponsors, and locations without leaving the host application.
• Integrate clinical trial data into AI-driven research: Enable LLMs to conduct clinical trial reviews, analyze research trends, and support evidence-based decision making.
• Support regulatory and compliance workflows: Retrieve structured data for regulatory submissions, competitive intelligence, and market research.

Built on the robust mcp-ts-template, this server provides a standardized, secure, and efficient way to expose ClinicalTrials.gov functionality via the MCP standard. It achieves this by integrating with the official ClinicalTrials.gov v2 API, ensuring compliance with rate limits and providing comprehensive error handling.

Developer Note: This repository includes a .clinerules file that serves as a developer cheat sheet for your LLM coding agent with quick reference for the codebase patterns, file locations, and code snippets.

Features

Core Utilities

Leverages the robust utilities provided by the mcp-ts-template:

• Logging: Structured, configurable logging (file rotation, stdout JSON, MCP notifications) with sensitive data redaction.
• Error Handling: Centralized error processing, standardized error types (McpError), and automatic logging.
• Configuration: Environment variable loading (dotenv) with comprehensive validation using Zod.
• Input Validation/Sanitization: Uses zod for schema validation and custom sanitization logic.
• Request Context: Tracking and correlation of operations via unique request IDs using AsyncLocalStorage.
• Type Safety: Strong typing enforced by TypeScript and Zod schemas.
• HTTP Transport: High-performance HTTP server using Hono, featuring session management and authentication support.
• Authentication: Robust authentication layer supporting JWT and OAuth 2.1, with fine-grained scope enforcement.
• Deployment: Multi-stage Dockerfile for creating small, secure production images with native dependency support.

ClinicalTrials.gov Integration

• Official API Integration: Comprehensive access to ClinicalTrials.gov v2 API endpoints with automatic JSON parsing.
• Advanced Search Capabilities: Complex query construction with filters for study status, geographic location, conditions, interventions, and sponsors.
• Full Study Metadata: Retrieve complete trial data including protocols, eligibility criteria, study design, outcomes, sponsors, and contact information.
• Flexible Field Selection: Choose specific data fields to retrieve for efficient API usage and reduced response sizes.
• Pagination Support: Handle large result sets with built-in pagination using pageSize and pageToken parameters.
• Data Cleaning: Automatically cleans and simplifies redundant information from API responses for easier consumption.
• Rate Limiting Compliance: Built-in request throttling to comply with ClinicalTrials.gov API guidelines.

Installation

Prerequisites

• Node.js (>=18.0.0)
• npm (comes with Node.js)

MCP Client Settings

Add the following to your MCP client's configuration file (e.g., cline_mcp_settings.json). This configuration uses npx to run the server, which will automatically install the package if not already present:

{
  "mcpServers": {
    "clinicaltrialsgov-mcp-server": {
      "command": "npx",
      "args": ["clinicaltrialsgov-mcp-server"],
      "env": {
        "MCP_LOG_LEVEL": "info"
      }
    }
  }
}

If running manually (not via MCP client for development or testing)

Install via npm

npm install clinicaltrialsgov-mcp-server

Alternatively Install from Source

1. Clone the repository:

   git clone https://github.com/cyanheads/clinicaltrialsgov-mcp-server.git
   cd clinicaltrialsgov-mcp-server
   

2. Install dependencies:

   npm install
   

3. Build the project:

   npm run build
   

Configuration

Environment Variables

Configure the server using environment variables. For local development, these can be set in a .env file at the project root or directly in your environment. Otherwise, you can set them in your MCP client configuration as shown above.

Project Structure

The codebase follows a modular structure within the src/ directory:

src/
├── index.ts              # Entry point: Initializes and starts the server
├── config/               # Configuration loading (env vars, package info)
│   └── index.ts
├── mcp-server/           # Core MCP server logic and capability registration
│   ├── server.ts         # Server setup, capability registration
│   ├── transports/       # Transport handling (stdio, http)
│   └── tools/            # MCP Tool implementations (subdirs per tool)
├── services/             # External service integrations
│   └── clinical-trials-gov/ # ClinicalTrials.gov API client and types
├── types-global/         # Shared TypeScript type definitions
└── utils/                # Common utility functions (logger, error handler, etc.)

For a detailed file tree, run npm run tree or see docs/tree.md.

Tools

The ClinicalTrials.gov MCP Server provides a comprehensive suite of tools for clinical trial research, callable via the Model Context Protocol.

Note: All tools support comprehensive error handling and return structured JSON responses.

Examples

Comprehensive usage examples for each tool are available in the examples/ directory.

• clinicaltrials_search_studies: View Example
• clinicaltrials_get_study: View Example
• clinicaltrials_analyze_trends: View Example

Development & Testing

Development Scripts

# Build the project (compile TS to JS in dist/ and make executable)
npm run build

# Clean build artifacts
npm run clean

# Clean build artifacts and then rebuild the project
npm run rebuild

# Format code with Prettier
npm run format

# Generate a file tree representation for documentation
npm run tree

Testing

This project uses Vitest for unit and integration testing.

# Run all tests once
npm test

# Run tests in watch mode
npm run test:watch

# Run tests and generate a coverage report
npm run test:coverage

Running the Server

# Start the server using stdio (default)
npm start
# Or explicitly:
npm run start:stdio

# Start the server using HTTP transport
npm run start:http

# Test the server locally using the MCP inspector tool (stdio transport)
npm run inspector

# Test the server locally using the MCP inspector tool (http transport)
npm run inspector:http

License

This project is licensed under the Apache License 2.0 - see the LICENSE file for details.

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