@fhirfly-io/mcp-server

@fhirfly-io/mcp-server

MCP (Model Context Protocol) server for connecting Claude Desktop to FHIRfly healthcare reference data APIs.

What is this?

This package lets Claude Desktop look up real healthcare reference data including:

• NDC - Drug products and packages (FDA)
• NPI - Healthcare provider identifiers (CMS)
• RxNorm - Drug terminology (NLM)
• LOINC - Laboratory codes (Regenstrief Institute)
• ICD-10 - Diagnosis and procedure codes (CMS)
• CVX/MVX - Vaccine codes (CDC)
• FDA Drug Labels - Prescribing information
• SNOMED CT - Clinical concepts (IPS free set)
• HCC - CMS Hierarchical Condition Category risk adjustment mappings
• OPCS-4 - UK NHS procedure classification codes
• dm+d - UK Dictionary of Medicines and Devices (NHS)
• UCUM - Unified Code for Units of Measure (NLM)
• RxClass - Drug classification hierarchy (NLM)
• HCPCS - Level II procedure and supply codes (CMS)
• MS-DRG - Diagnosis Related Groups for inpatient payment (CMS)
• POS - Place of Service codes for claims submission (CMS)
• J-Code/NDC Crosswalk - Bidirectional HCPCS J-code to NDC mapping (CMS)
• DDI Reference — Drug-drug interaction text from FDA labels + RxNorm enrichment
• Connectivity - Provider FHIR endpoints and Direct addresses
• SMA - State Medicaid Agency FHIR endpoint directory (CMS)
• Claims Intelligence - NCCI edits, MUE limits, PFS/RVU data, coverage determinations

When you ask Claude about medications, providers, or clinical codes, it can look up accurate, current information instead of relying on training data.

Prerequisites

• Claude Desktop - Download from claude.ai/download
• Node.js 18+ - Download from nodejs.org
• FHIRfly API Key - Get one at fhirfly.io (free tier available)

Quick Setup

Step 1: Get a FHIRfly API Key

• Go to fhirfly.io and sign up
• Navigate to Dashboard > Credentials
• Click Create Credential and select MCP (Claude Desktop)
• Copy your API key (starts with ffly_)

Step 2: Configure Claude Desktop

Find your Claude Desktop config file:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
• Windows: %APPDATA%\Claude\claude_desktop_config.json

Add the FHIRfly server configuration:

{
  "mcpServers": {
    "fhirfly": {
      "command": "npx",
      "args": ["-y", "@fhirfly-io/mcp-server"],
      "env": {
        "FHIRFLY_API_KEY": "ffly_live_your_key_here"
      }
    }
  }
}

Replace ffly_live_your_key_here with your actual API key.

Step 3: Restart Claude Desktop

Completely quit Claude Desktop and reopen it. The FHIRfly tools should now be available.

Verify It Works

Try asking Claude:

• "What is NDC 0069-0151-01?"
• "Look up NPI 1234567893"
• "Search for COVID vaccines in the CVX database"
• "What are the drug interactions for Lipitor?"
• "Which states have implemented Medicaid FHIR endpoints?"
• "Show me the FHIR endpoint details for California's Medicaid program"
• "What is the UCUM code for milligrams per deciliter?"
• "Convert 100 mg to grams"
• "What drugs are in the HMG-CoA Reductase Inhibitors class?"
• "Check interactions between aspirin and warfarin"

Claude should use the FHIRfly tools to look up real data.

Available Tools

Tool	Description
ndc_get	Look up drug by NDC code
ndc_search	Search drugs by name, ingredient, etc.
npi_get	Look up provider by NPI number
npi_search	Search providers by name, specialty, location
rxnorm_get	Look up drug by RxCUI
rxnorm_search	Search drug terminology
loinc_get	Look up lab test by LOINC code
loinc_search	Search lab codes
icd10_get	Look up diagnosis/procedure code
icd10_search	Search ICD-10 codes
cvx_get	Look up vaccine by CVX code
cvx_search	Search vaccine codes
mvx_get	Look up vaccine manufacturer
mvx_search	Search manufacturers
fda_label_lookup	Look up FDA drug label
fda_label_search	Search drug labels
fda_label_safety	Get safety info (boxed warnings, contraindications)
fda_label_interactions	Get drug interaction info
fda_label_dosing	Get dosing information
fda_label_sections	Get specific label sections
snomed_get	Look up clinical concept by SNOMED CT ID
snomed_search	Search SNOMED CT IPS concepts
snomed_mappings	Find cross-terminology mappings for a SNOMED concept
npi_connectivity	Look up provider connectivity (FHIR endpoints)
sma_list_states	List states with Medicaid FHIR endpoint status
sma_get_state	Get SMA FHIR endpoint details for a state
sma_stats	Get aggregate SMA implementation statistics
ncci_validate	Check if two codes can be billed together (NCCI)
mue_lookup	Look up max units of service (MUE limits)
pfs_lookup	Look up Medicare fee schedule / RVU data
coverage_check	Check LCD/NCD coverage determinations
HCPCS / MS-DRG / POS / J-Code Tools
hcpcs_get	Look up an HCPCS Level II procedure/supply code
hcpcs_modifier_get	Look up an HCPCS modifier code
hcpcs_search	Search HCPCS Level II codes
msdrg_get	Look up an MS-DRG code
msdrg_search	Search MS-DRG codes
pos_get	Look up a Place of Service code
jcode_by_hcpcs	Find NDCs mapped to a J-code/HCPCS code
jcode_by_ndc	Find HCPCS codes mapped to an NDC
HCC / OPCS-4 Tools
hcc_get	Look up HCC risk adjustment mappings for an ICD-10 code
hcc_reverse	Find all ICD-10 codes mapping to a given HCC category
hcc_search	Search the HCC crosswalk by code, model, or category
opcs4_get	Look up an OPCS-4 UK NHS procedure code
opcs4_search	Search OPCS-4 procedure codes
dm+d Tools
dmd_get	Look up a UK dm+d medicine/device by SNOMED code
dmd_search	Search UK dm+d medicines and devices
UCUM Tools
ucum_get	Look up a UCUM unit code (e.g., mg, mL, kg/m2)
ucum_search	Search units of measure by name or description
ucum_validate	Validate a UCUM expression for correctness
ucum_convert	Convert a value between compatible UCUM units
RxClass Tools
rxclass_get	Look up a drug class by class ID
rxclass_search	Search drug classifications by name or type
rxclass_members	List drugs belonging to a drug class
DDI Tools
check_drug_interactions	Check drug-drug interactions for multiple drugs (FDA label text + RxNorm)
Batch Tools
ndc_batch	Look up multiple NDC codes (max 500)
npi_batch	Look up multiple NPI numbers (max 100)
icd10_batch	Look up multiple ICD-10 codes (max 100)
rxnorm_batch	Look up multiple RxCUIs (max 100)
loinc_batch	Look up multiple LOINC codes (max 100)
cvx_batch	Look up multiple CVX codes (max 100)
mvx_batch	Look up multiple MVX codes (max 100)
fda_label_batch	Look up multiple FDA labels (max 50)

Configuration Options

Environment Variable	Description	Default
FHIRFLY_API_KEY	Your FHIRfly API key (required)	-
FHIRFLY_API_URL	API base URL	https://api.fhirfly.io
FHIRFLY_DEBUG	Enable debug logging (1 or true)	false
FHIRFLY_TIMEOUT	Fetch timeout in milliseconds	30000

Troubleshooting

"FHIRFLY_API_KEY environment variable is required"

Your API key isn't configured. Make sure:

• You have a valid API key from fhirfly.io
• It's set in the env section of your Claude Desktop config
• The key starts with ffly_

"Invalid API key format"

FHIRfly API keys start with ffly_. Check that you copied the full key.

"Authentication failed"

Your API key may be invalid or expired. Generate a new one at fhirfly.io/dashboard/credentials.

Claude doesn't show FHIRfly tools

• Make sure you completely quit and restarted Claude Desktop
• Check your config file syntax (must be valid JSON)
• Enable debug mode to see what's happening:

{
  "mcpServers": {
    "fhirfly": {
      "command": "npx",
      "args": ["-y", "@fhirfly-io/mcp-server"],
      "env": {
        "FHIRFLY_API_KEY": "your_key",
        "FHIRFLY_DEBUG": "1"
      }
    }
  }
}

"Rate limit exceeded"

You've hit your plan's rate limit. Wait a moment and try again, or upgrade your plan at fhirfly.io.

How It Works

┌─────────────────┐     ┌─────────────────┐     ┌─────────────────┐
│  Claude Desktop │────▶│  This Package   │────▶│  FHIRfly API    │
│                 │     │  (runs locally) │     │  (cloud)        │
│  "What is       │◀────│                 │◀────│                 │
│   NDC 123..."   │     │  Translates MCP │     │  Returns drug   │
│                 │     │  ↔ HTTPS        │     │  data           │
└─────────────────┘     └─────────────────┘     └─────────────────┘

This package runs on your computer as a bridge between Claude Desktop and the FHIRfly API. It:

• Receives requests from Claude Desktop via stdin
• Translates them to HTTPS requests to FHIRfly
• Returns the results to Claude via stdout

Your API key is sent to FHIRfly over HTTPS. No healthcare data is stored locally.

Links

• FHIRfly Documentation
• MCP Setup Guide
• Get an API Key
• Report Issues

Data Sources & Licensing

Data Source	Provider	License
NDC Directory	FDA	Public domain
NPPES (NPI)	CMS	Public domain
RxNorm	NLM (NIH)	UMLS license (free)
LOINC	Regenstrief Institute	Free with attribution
ICD-10-CM/PCS	CMS	Public domain
CVX/MVX	CDC	Public domain
FDA Drug Labels	FDA/openFDA	Public domain
SNOMED CT IPS	SNOMED International	CC BY 4.0
HCC Crosswalk	CMS	Public domain
OPCS-4	NHS England	OGL v3.0 (Crown copyright)
dm+d	NHS England / NHSBSA	OGL v3.0 (Crown copyright)
UCUM	NLM (NIH) / Regenstrief Institute	Free with attribution
RxClass	NLM (NIH)	UMLS license (free)
SMA Endpoint Directory	CMS	Public domain
HCPCS Level II	CMS	Public domain
MS-DRG	CMS	Public domain
Place of Service	CMS	Public domain
J-Code/NDC Crosswalk	CMS	Public domain
NCCI/MUE/PFS	CMS	Public domain
DDI Reference	FDA + NLM	Public domain

FHIRfly aggregates and indexes these data sources. See fhirfly.io/docs for details.

Changelog

See CHANGELOG.md for release history.

License

MIT - see LICENSE