LangCare MCP FHIR Server

Enterprise-grade MCP Server for FHIR-based EMRs, designed for robust deployments in agentic AI platforms. Fully written in Go with enterprise-grade security and generic FHIR operations that work with any FHIR R4 resource type. Ships with a 40+ Clinical Skills Library — agent-agnostic workflow guides covering medication management, lab interpretation, clinical decision support, documentation, population health, and more.

Installation

Install via npm:

npm install -g @langcare/langcare-mcp-fhir

Or use directly without installation:

npx @langcare/langcare-mcp-fhir -config /path/to/config.yaml

Quick Configuration

LangCare MCP FHIR connects Claude to your FHIR-based EMR system. You need a YAML configuration file pointing to your backend.

1. Get a Config Template

Choose your backend:

• EPIC: config.epic.example.yaml
• Cerner: config.cerner.example.yaml
• GCP Healthcare API: config.gcp.example.yaml
• Any FHIR R4 Server: config.base.example.yaml

2. Configure Claude Desktop

Add to your Claude Desktop config file (~/.config/Claude/claude_desktop_config.json):

{
  "mcpServers": {
    "langcare-mcp-fhir": {
      "command": "langcare-mcp-fhir",
      "args": ["-config", "/path/to/your/config.yaml"]
    }
  }
}

On macOS, the config is typically at:

~/Library/Application\ Support/Claude/claude_desktop_config.json

3. Restart Claude Desktop

Close and reopen Claude Desktop. The FHIR tools will now be available.

Need detailed setup help? See the Local Testing Guide.

Architecture

This MCP server acts as an intelligent proxy between AI agents and FHIR R4 servers. It exposes 4 generic FHIR operations through the Model Context Protocol (MCP), enabling AI-powered workflows for any FHIR resource type.

Key Design:

• MCP SDK: Official github.com/modelcontextprotocol/go-sdk (Anthropic/Google maintained)
• FHIR Client: Generic HTTP client working with any FHIR R4 server
• Transport: stdio and Streamable HTTP
• Backend: Proxy to existing FHIR server (no database)
• Language: 100% Go for high performance and reliability

4 Generic MCP Tools

All tools work with any FHIR resource type (Patient, Observation, Medication, etc.):

1. fhir_read

Read a FHIR resource by type and ID.

{
  "resourceType": "Patient",
  "id": "example-123"
}

2. fhir_search

Search FHIR resources with query parameters.

{
  "resourceType": "Patient",
  "queryParams": "name=John&birthdate=gt1990-01-01"
}

3. fhir_create

Create a new FHIR resource.

{
  "resourceType": "Observation",
  "resource": {
    "resourceType": "Observation",
    "status": "final",
    "code": { ... },
    "subject": { "reference": "Patient/123" }
  }
}

4. fhir_update

Update an existing FHIR resource.

{
  "resourceType": "Patient",
  "id": "example-123",
  "resource": {
    "resourceType": "Patient",
    "id": "example-123",
    "name": [{ "family": "Smith" }]
  }
}

Security Architecture

LangCare MCP FHIR implements a two-layer security model for HIPAA-compliant healthcare data access:

┌─────────────┐         ┌──────────────┐         ┌─────────────┐
│   Claude    │ Auth1   │  MCP Server  │ Auth2   │  FHIR API   │
│   Client    │────────▶│   (Go)       │────────▶│   (EMR)     │
└─────────────┘         └──────────────┘         └─────────────┘

Auth1: MCP Client Authentication (Bearer Token/API Key)
Auth2: FHIR Backend Authentication (Bearer/OAuth2/SMART on FHIR)

Security Features

• ✅ TLS 1.3 encryption for HTTP transport
• ✅ PHI Scrubbing in logs (enabled by default)
• ✅ HIPAA-compliant audit logging
• ✅ No persistent PHI storage (stateless proxy)
• ✅ Secrets via environment variables (never in config files)
• ✅ OAuth 2.0 with automatic token refresh
• ✅ mTLS support for service-to-service communication
• ✅ Rate limiting per client

Supported Authentication Methods

• Bearer Token - Simple API key authentication
• OAuth2 - Full OAuth2 flow with token refresh
• SMART on FHIR - EPIC, Cerner, and other EMR standards
• Basic Auth - Username/password authentication
• Custom - Extensible for additional auth methods

For complete security documentation, see Security Guide:

• HIPAA compliance checklist
• OAuth configuration for EPIC/Cerner/GCP
• Kubernetes security manifests
• Credential management procedures
• Audit logging implementation

Agent Usage

AI agents use LangCare MCP FHIR Server to help healthcare professionals access and manage patient health records through 4 FHIR tools. The server handles EMR authentication, allowing agents to focus on clinical workflows while maintaining strict privacy and accuracy standards.

Agent capabilities:

• Search, Read, Create, Update - Any FHIR R4 resource (Patient, Observation, Medication, etc.)
• Patient privacy - Use partial identifiers, confirm identity before updates
• Clinical accuracy - Verify data, use standard codes (LOINC, SNOMED, RxNorm)
• Professional communication - Structure responses with context, findings, and next steps

Common workflows:

• Patient lookup: Search by name/DOB → verify identity → read full details
• Clinical review: Retrieve labs, vitals, medications → present with reference ranges
• Documentation: Extract structured data → map to FHIR resources → confirm → create
• Updates: Verify existing resource → modify → confirm changes → update

System support:

• Works with any FHIR R4 resource type (60+ types including DocumentReference, Binary, Media)
• Automatic authentication and token refresh to EPIC, Cerner, GCP Healthcare API
• HIPAA-compliant PHI handling with audit logging
• Comprehensive OAuth2 scopes for clinical data access

📖 Complete guide: Agent Prompt Guide - System prompt, tool examples, workflows, and error handling

Clinical Skills Library (Optional)

40+ agent-agnostic clinical workflow guides that teach AI agents how to perform complex healthcare tasks using the MCP server's 4 FHIR tools (fhir_search, fhir_read, fhir_create, fhir_update).

• Optional - The MCP server works without them
• Portable - Work with Claude, ChatGPT, Gemini, or any AI agent
• Evidence-based - Built on USPSTF, ADA, ACC/AHA, CDC, ACOG, KDIGO, and other society guidelines
• Copy-paste ready - Add a skill's SKILL.md to your agent's system prompt or custom instructions

Skill Categories (40 Skills)

| Category | Skills | Examples | |----------|--------|----------| | Patient Data & Summary | 5 | Demographics, clinical summary (CCD-style), problem list audit, allergy review, insurance coverage | | Medication Management | 5 | Med reconciliation, drug interactions (CYP450), adherence (MPR/PDC), Beers Criteria, opioid risk (ORT/MME) | | Lab & Diagnostics | 5 | Lab interpretation, critical values (CAP/CLIA), pre-op labs, diabetes panel (ADA), renal function (KDIGO) | | Clinical Decision Support | 5 | Sepsis (qSOFA/SOFA), cardiovascular risk (ASCVD/HEART), VTE (Wells/Caprini), fall risk (Morse), pneumonia (CURB-65) | | Care Coordination | 5 | Discharge planning (LACE), referrals, care gaps (USPSTF), transitions of care (I-PASS), follow-up tasks | | Documentation | 5 | SOAP notes, H&P, progress notes, discharge summaries, procedure notes | | Population Health | 5 | Panel overview, quality measures (HEDIS), chronic disease registries, immunization status (CDC), preventive care compliance | | Specialty | 5 | Prenatal (ACOG), pediatric growth (WHO/CDC), mental health (PHQ-9/GAD-7), oncology (TNM/RECIST), chronic pain |

Full catalog with links: skills/README.md

How to Use Skills

1. Browse the skills/core/ directory and pick a skill
2. Copy the skill's SKILL.md content into your AI agent's system prompt or custom instructions
3. Reference files in each skill's references/ subdirectory contain detailed clinical knowledge (scoring criteria, code tables, thresholds) that can optionally be included for deeper clinical accuracy

# Example: Add medication-reconciliation skill to your agent
skills/core/medication-management/medication-reconciliation/
├── SKILL.md              # Copy this into agent instructions
└── references/
    ├── reconciliation-process.md   # Joint Commission standards
    └── high-risk-medications.md    # ISMP high-alert drug list

Integration guides: Claude | ChatGPT | Gemini

Community contributions welcome - see CONTRIBUTING.md for guidelines.

Development & Testing

Build from Source

make build

Run Locally (stdio mode)

make run
# or
./bin/langcare-mcp-fhir -config configs/config.local.yaml

Run in HTTP Mode (Streamable HTTP)

make run-http
# or
./bin/langcare-mcp-fhir -http -port 8080 -config configs/config.yaml

Starts the server with Streamable HTTP transport on /mcp and health check on /health.

Run Tests

make test

Lint Code

make lint

Deploy to Fly.io (Remote Streamable HTTP)

Deploy as a remote MCP server with Streamable HTTP transport, accessible by any MCP-compatible AI agent from anywhere.

# Install Fly CLI
brew install flyctl
fly auth login

# Create app
fly apps create --name langcare-mcp-dev

# Set CONFIG_FILE in fly/fly.dev.toml [env] block for your provider (EPIC or GCP)
# Then set secrets (EPIC example):
fly secrets set \
  EPIC_BASE_URL="https://fhir.epic.com/interconnect-fhir-oauth/api/FHIR/R4" \
  EPIC_CLIENT_ID="your-client-id" \
  EPIC_TOKEN_URL="https://fhir.epic.com/interconnect-fhir-oauth/oauth2/token" \
  EPIC_PRIVATE_KEY_B64="$(base64 < keys/epic/private-key.pem)" \
  MCP_AUTH_TOKENS="your-token" \
  --app langcare-mcp-dev

# Deploy
fly deploy -c fly/fly.dev.toml --app langcare-mcp-dev

# Verify
curl https://langcare-mcp-dev.fly.dev/health

Connect any MCP client to:

URL:   https://langcare-mcp-dev.fly.dev/mcp
Auth:  Authorization: Bearer your-token

Claude Desktop (claude_desktop_config.json):

{
  "mcpServers": {
    "langcare-fhir": {
      "url": "https://langcare-mcp-dev.fly.dev/mcp",
      "headers": {
        "Authorization": "Bearer your-token"
      }
    }
  }
}

Supports EPIC and GCP Healthcare API providers. See fly/README.md for provider setup, secrets, and full deployment guide.

Local Testing with EPIC

For step-by-step instructions on setting up EPIC credentials and testing locally:

📖 Local Testing Guide

This guide covers:

• Generating RSA keys and JWKS
• Configuring EPIC credentials
• Running the server locally
• Testing with Claude Desktop
• Troubleshooting common issues

Quick credential test:

# Test your EPIC credentials before running the server
go run test/test_epic_token.go "your-client-id" "/path/to/private-key.pem"

Project Structure

langcare-mcp-fhir/
├── cmd/
│   └── server/
│       └── main.go                          # Entry point
├── internal/
│   ├── audit/
│   │   └── logger.go                        # HIPAA audit logging
│   ├── config/
│   │   └── config.go                        # YAML configuration loading
│   ├── fhir/
│   │   ├── client.go                        # FHIR HTTP client interface
│   │   ├── types.go                         # FHIR client types
│   │   └── providers/                       # Backend implementations
│   │       ├── base.go                      # Base HTTP provider
│   │       ├── epic.go                      # EPIC OAuth2 provider
│   │       ├── cerner.go                    # Cerner OAuth2 provider
│   │       └── gcp.go                       # GCP Healthcare API provider
│   ├── mcp/
│   │   └── server.go                        # MCP server initialization
│   ├── middleware/
│   │   ├── auth.go                          # MCP authentication
│   │   └── rate_limit.go                    # Rate limiting
│   ├── tools/                               # MCP tool implementations
│   │   ├── registry.go                      # Tool registry
│   │   ├── fhir_read.go                     # Read FHIR resource
│   │   ├── fhir_search.go                   # Search FHIR resources
│   │   ├── fhir_create.go                   # Create FHIR resource
│   │   └── fhir_update.go                   # Update FHIR resource
│   └── transport/
│       ├── stdio.go                         # stdio transport (Claude Desktop)
│       └── http.go                          # Streamable HTTP transport (production)
├── pkg/
│   └── types/
│       └── errors.go                        # Custom error types
├── configs/
│   ├── config.epic.example.yaml             # Example configuration for EPIC
│   ├── config.cerner.example.yaml           # Example configuration for Cerner
│   ├── config.gcp.example.yaml              # Example configuration for GCP
│   └── config.base.example.yaml             # Example configuration for any FHIR R4 server
├── docs/
│   ├── AGENT_PROMPT.md                      # AI agent system prompt
│   ├── EPIC-APP-SECURITY.md                 # EPIC authentication setup
│   ├── EPIC-SCOPES.md                       # OAuth2 scopes reference
│   ├── LOCAL-TESTING.md                     # Local development guide
│   └── SECURITY.md                          # Production security guide
├── test/
│   ├── README.md                            # Test documentation
│   └── test_epic_token.go                   # EPIC OAuth2 token tester
├── fly/
│   ├── Dockerfile                           # Multi-stage Go build for Fly.io
│   ├── docker-entrypoint.sh                 # Key materialization + server startup
│   ├── fly.dev.toml                         # Fly.io dev deployment config
│   ├── config.fly.epic.yaml                 # Fly.io EPIC provider config
│   ├── config.fly.gcp.yaml                  # Fly.io GCP provider config
│   └── README.md                            # Fly.io deployment guide
├── scripts/
│   └── create_jwks.sh                       # Generate JWKS from public key (used for EPIC FHIR)
├── bin/                                     # Build output (gitignored)
│   └── langcare-mcp-fhir                    # Compiled binary
├── go.mod                                   # Go module definition
├── go.sum                                   # Go module checksums
├── Makefile                                 # Build commands
└── README.md                                # This file

Note: The following are gitignored and not committed:

• keys/ - Private keys and credentials
• config.local.*.yaml - Local configuration files
• bin/ - Compiled binaries
• .env - Environment variables

Documentation

Getting Started

• 📖 Local Development & Testing Guide - Complete guide for local setup and testing
• 🚀 Installation & Configuration - Quick setup guide above

Agent Integration

• 🤖 Agent Prompt Guide - Complete guide for AI agents using LangCare MCP FHIR (tool examples, workflows, best practices)

Security & Authentication

• 🛡️ Security Documentation - Complete security architecture and HIPAA compliance
• 🔐 EPIC Setup Guide - JWT authentication, key generation, and JWKS registration
• 📋 EPIC Scopes Reference - Complete OAuth2 scopes guide for FHIR resources
• 🔑 Authentication Methods - Supported auth methods

Deployment

• Fly.io Deployment Guide - Remote Streamable HTTP deployment, provider configs, secrets, Docker

Development & Testing

• 🧪 Testing Methods - Claude Desktop, MCP Inspector, manual testing, and automation
• 📦 Project Structure - Directory layout and architecture
• 🔧 Build Commands - Development workflow

Dependencies

• github.com/modelcontextprotocol/go-sdk - Official MCP SDK
• gopkg.in/yaml.v3 - Configuration parsing
• golang.org/x/oauth2 - OAuth2 client library
• github.com/golang-jwt/jwt/v5 - JWT signing and verification
• Go 1.25+

HIPAA Compliance

• PHI scrubbing enabled by default
• Never logs patient identifiers
• TLS support for HTTP transport
• Proper error sanitization
• Audit logging ready
• Stateless proxy design (no persistent storage)

Testing

Public Test Server

Default configuration uses HAPI FHIR public test server (https://hapi.fhir.org/baseR4) for immediate testing without setup.

Test Your Setup

• 📖 Local Development & Testing Guide - Complete guide for setup, testing with Claude Desktop, MCP Inspector, and automation
• 🔐 EPIC Security Setup - Detailed EPIC authentication guide
• 🛡️ Security Documentation - Production deployment and security

Contributing

We welcome contributions from healthcare professionals, developers, and informaticists!

There are three main ways to contribute:

1. Core MCP Server (Go Development)

• Bug fixes and performance improvements
• New FHIR provider implementations (AllScripts, Athenahealth, etc.)
• Security enhancements and observability features
• Testing and CI/CD improvements

2. Clinical Skills (Healthcare Workflows)

• Evidence-based clinical workflows using FHIR
• Specialty-specific protocols (cardiology, oncology, etc.)
• Population health and quality measure workflows
• Clinical decision support algorithms

Skills are agent-agnostic workflow guides that work across Claude, ChatGPT, and Gemini. No coding required - just clinical expertise and FHIR knowledge!

3. Agent Integrations (Platform Setup)

• Setup guides for new AI platforms
• Deployment examples (Docker, Kubernetes, cloud)
• Monitoring and observability setups
• CI/CD pipelines

Get started: Read CONTRIBUTING.md for detailed guidelines, code standards, and submission process.

Recognition: Contributors are credited in README, release notes, and skill/integration author credits. Outstanding contributors may be invited as maintainers.

Questions? Open a GitHub Discussion or issue!

Community

• GitHub Discussions - Ask questions, share ideas: https://github.com/langcare/langcare-mcp-fhir/discussions
• GitHub Issues - Report bugs, request features: https://github.com/langcare/langcare-mcp-fhir/issues
• Contributing Guide - How to contribute: https://github.com/langcare/langcare-mcp-fhir/blob/main/CONTRIBUTING.md
• Skills - Clinical workflows: https://github.com/langcare/langcare-mcp-fhir/blob/main/skills/README.md

License

See LICENSE file.

Built with ❤️ by the LangCare team and contributors.

Improving healthcare through better AI infrastructure.