Formulary Server

Model Context Protocol (MCP) server providing unified access to drug formulary data from US ACA marketplace health insurance plans.

Features

• Unified drug search across ~15,000 plans from ~735 issuers
• Coverage details: tier levels, copays, coinsurance
• Restriction info: prior authorization, step therapy, quantity limits
• Plan comparison: compare drug coverage across plans
• State filtering: filter results by state
• Full-text search: fast drug name search with FTS5

Installation

cd formulary-mcp-server
npm install

Option 1: Download Pre-built Database

npm run download:db

Option 2: Build Database from Source

# Download issuer index from CMS
npm run download:index

# Download formulary files for all issuers
npm run download:files

# Build SQLite database
npm run build:db

Build and Run

npm run build
npm start

Usage

{
  "mcpServers": {
    "formulary": {
      "command": "node",
      "args": ["/path/to/formulary-mcp-server/build/index.js"]
    }
  }
}

Tool: formulary_info

Single unified tool with multiple methods:

Methods

Method	Description	Required Params
search_drug	Search drugs by name	drug_name
get_drug_details	Get full drug info with coverage	rxnorm_id
get_plan_formulary	Get drugs covered by a plan	plan_id
get_plan_details	Get plan info and tier structure	plan_id
compare_coverage	Compare drug across plans	rxnorm_id
search_plans	Search plans by state/issuer	-
get_restrictions	Get PA/ST/QL requirements	rxnorm_id
get_alternatives	Find drugs in same tier	rxnorm_id, plan_id
get_statistics	Get database statistics	-

Example Usage

Search for a drug:

{
  "method": "search_drug",
  "drug_name": "metformin",
  "state": "CA",
  "limit": 10
}

Get drug details:

{
  "method": "get_drug_details",
  "rxnorm_id": "860975",
  "state": "CA"
}

Compare coverage:

{
  "method": "compare_coverage",
  "rxnorm_id": "860975",
  "state": "TX",
  "limit": 20
}

Get plan formulary:

{
  "method": "get_plan_formulary",
  "plan_id": "12345VA0010001",
  "tier": "GENERIC"
}

Get restrictions:

{
  "method": "get_restrictions",
  "rxnorm_id": "860975",
  "plan_id": "12345VA0010001"
}

Response Format

Drug Search Response

{
  "method": "search_drug",
  "query": "metformin",
  "count": 5,
  "results": [
    {
      "rxnorm_id": "860975",
      "drug_name": "Metformin Hydrochloride 500 MG Oral Tablet",
      "plan_count": 245,
      "tiers": ["GENERIC", "PREFERRED-BRAND"]
    }
  ]
}

Drug Details Response

{
  "method": "get_drug_details",
  "drug": {
    "rxnorm_id": "860975",
    "drug_name": "Metformin Hydrochloride 500 MG Oral Tablet"
  },
  "coverage_summary": {
    "total_plans": 245,
    "plans_with_pa": 12,
    "plans_with_st": 5,
    "plans_with_ql": 89
  },
  "coverage": [
    {
      "plan_id": "12345CA0010001",
      "drug_tier": "GENERIC",
      "prior_authorization": false,
      "step_therapy": false,
      "quantity_limit": true,
      "marketing_name": "Blue Shield Gold",
      "issuer_name": "Blue Shield of California",
      "copay_amount": 10.00,
      "coinsurance_rate": 0.20
    }
  ]
}

Data Coverage

Aspect	Coverage
Plans	~5,500 ACA marketplace plans
Issuers	~150 insurance companies
Drugs	~13,000 unique medications
Templates	~800 unique formulary templates
States	15+ states
Data	Tier, PA, step therapy, quantity limits

Data Source

Data is sourced from the CMS QHP (Qualified Health Plan) Provider & Formulary APIs:

• https://github.com/CMSgov/QHP-provider-formulary-APIs
• https://data.healthcare.gov/

Note: This covers ACA marketplace plans only. Employer-sponsored and Medicare Advantage plans are not included.

License

MIT

References

• CMS QHP Provider & Formulary APIs
• DaVinci Drug Formulary IG
• CMS Interoperability APIs