Overview

US healthcare provider directory over the NPPES NPI Registry, with plain-language specialty terms resolved offline against a bundled NUCC taxonomy. Search providers by name, organization, location, and specialty; decode NPIs into professional-practice provider records; and resolve or browse the NUCC taxonomy directly. Runs as a stdio process, a local Streamable HTTP server, or the public hosted endpoint above.

Tools

Resources

All resource data is also reachable via tools; the resources are convenience twins for resource-capable clients.

Capability reference

npi_search_providers _tool

• Inputs: name_search or first_name / last_name (individuals), organization_name (organizations), provider_type, city / state / postal_code (practice addresses only), and a plain-language specialty resolved through the bundled NUCC taxonomy, or an exact taxonomy_description (never both). At least one criterion is required, state alone is rejected, and individual and organization criteria can't be mixed. A trailing * needs at least 2 leading characters; postal_code takes 5 or 9 digits or a 2–9 digit prefix ending in *. limit 1–200 (default 10), skip 0–1000
• Output: compact rows (npi, name, primary taxonomy, primary practice city / state / postalCode, status), with matchedLocation / matchedOtherName naming the practice location or other name a row matched through, and resolvedTaxonomies / appliedTaxonomyDescription echoing the specialty resolution. No true total is reported: a full page names nextPage, and the terminal window (skip 1000, limit 200) returns continuationPostalCodes that continue the search
• Typed error reasons: no_search_criteria, conflicting_specialty, mixed_provider_criteria, unresolved_specialty, invalid_search_field

npi_get_provider _tool

• Accepts npis: a single NPI or up to 10, each exactly 10 digits and checked against its NPI check digit before any API call
• Partitions the batch into found (decoded records: taxonomies with license, practice addresses, credential, identifiers, FHIR/Direct endpoints, status — only LOCATION address rows for individual providers, so their mailing address is withheld), notFound (confirmed absence), errored (upstream failure — retry these), and invalid (failed the check digit, never looked up)
• Typed error reasons: invalid_npi_format (every NPI failed the check digit), none_found (every NPI looked up is a confirmed absence); an upstream failure surfaces as that underlying error instead

npi_lookup_taxonomy _tool

• Modes: resolve (query → matching active codes), get (exact code → full entry with NUCC's notes), browse (walk grouping → classification → specialization, filterable by grouping and NPI section); resolve / browse take limit (≤50, default 20) and skip (0–1000) and disclose truncated
• Every entry carries status (active / inactive) and an inactive code's replacedBy; resolve excludes inactive codes, while get and browse return them. A resolved entry's specialization (or classification when absent) is the exact value npi_search_providers.taxonomy_description accepts
• Typed error reasons: no_match, missing_argument

npi://provider/{npi} _resource

• Returns the same decoded record as npi_get_provider, for one NPI, as application/json — only LOCATION address rows are kept for individual providers
• npi must be a well-formed 10-digit NPI; invalid_npi_format when it fails the NPI check digit (no registry request), no_record when the registry has none (deactivated or never enumerated)

npi://taxonomy/{code} _resource

• Returns the same entry as npi_lookup_taxonomy mode get (NUCC notes, status, and replacedBy included; inactive codes stay readable), as application/json; cached publicly for 24 hours
• code must match ^\d{3}[A-Z0-9]{6}X$; no_match when no entry exists for the code

Features

Built on @cyanheads/mcp-ts-core: stdio and Streamable HTTP transports, pluggable auth (none / jwt / oauth), swappable storage (in-memory, filesystem, Supabase, Cloudflare KV/R2/D1), structured logging with optional OpenTelemetry tracing.

NPI/NPPES-specific:

• Keyless — runs against the public CMS NPPES NPI Registry API (v2.1) with no API key or account
• Bundled NUCC taxonomy — the 883-code Healthcare Provider Taxonomy (v26.1) ships in the image and loads into an in-memory index at startup, so specialty resolution and code lookups work fully offline with no second upstream
• Specialty resolution turns a vague term ("heart doctor") into the precise taxonomy description the registry filters on, and echoes the match back for the agent to verify
• Detects the registry's quirk of returning HTTP 200 with an Errors[] body on validation failure and maps it to typed, recoverable error reasons

Agent-friendly output:

• Provenance on search — the resolved taxonomy and the exact taxonomy_description sent to the registry are echoed back, so agents can see what was actually searched and re-run with a different code
• Honest pagination — the returned count is disclosed as the page size, never a fabricated grand total; a full page names the exact next page, and a broad query that hits the 1200-match reachable ceiling gets the postal-code prefixes that continue it
• Graceful partial failure — npi_get_provider returns per-NPI found / notFound / errored / invalid rows instead of failing the whole batch

Getting started

Public Hosted Instance

A public instance is available at https://npi-providers.caseyjhand.com/mcp — no installation required. Point any MCP client at it via Streamable HTTP, with this client config:

{
  "mcpServers": {
    "npi-providers-mcp-server": {
      "type": "streamable-http",
      "url": "https://npi-providers.caseyjhand.com/mcp"
    }
  }
}

Self-Hosted / Local

Add the following to your MCP client configuration file. No API key is required — the upstream NPPES registry is keyless.

{
  "mcpServers": {
    "npi-providers-mcp-server": {
      "type": "stdio",
      "command": "bunx",
      "args": ["@cyanheads/npi-providers-mcp-server@latest"],
      "env": {
        "MCP_TRANSPORT_TYPE": "stdio",
        "MCP_LOG_LEVEL": "info"
      }
    }
  }
}

Or with npx (no Bun required):

{
  "mcpServers": {
    "npi-providers-mcp-server": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "@cyanheads/npi-providers-mcp-server@latest"],
      "env": {
        "MCP_TRANSPORT_TYPE": "stdio",
        "MCP_LOG_LEVEL": "info"
      }
    }
  }
}

Or with Docker:

{
  "mcpServers": {
    "npi-providers-mcp-server": {
      "type": "stdio",
      "command": "docker",
      "args": ["run", "-i", "--rm", "-e", "MCP_TRANSPORT_TYPE=stdio", "ghcr.io/cyanheads/npi-providers-mcp-server:latest"]
    }
  }
}

For Streamable HTTP, set the transport and start the server:

MCP_TRANSPORT_TYPE=http MCP_HTTP_PORT=3010 bun run start:http
# Server listens at http://localhost:3010/mcp

Prerequisites

• Bun v1.4.0 or higher (or Node.js v24+).
• No API key — the NPPES NPI Registry API is public and keyless. The NUCC taxonomy is bundled, so there is no second data source to provision.

Installation

1. Clone the repository:

git clone https://github.com/cyanheads/npi-providers-mcp-server.git

2. Navigate into the directory:

cd npi-providers-mcp-server

3. Install dependencies:

bun install

4. Configure environment (optional):

cp .env.example .env
# edit .env only if you need to override the NPPES base URL or timeout

Configuration

No required variables — the server runs out of the box against the keyless NPPES registry. All variables below are optional overrides.

See .env.example for the full list of optional overrides.

Running the server

Local development

• Build and run:

  shCopy

  # One-time build
  bun run rebuild
  
  # Run the built server
  bun run start:stdio
  # or
  bun run start:http
  

• Run checks and tests:

  shCopy

  bun run devcheck   # Lint, format, typecheck, security
  bun run test       # Vitest test suite
  bun run lint:mcp   # Validate MCP definitions against spec
  

Docker

docker build -t npi-providers-mcp-server .
docker run --rm -e MCP_TRANSPORT_TYPE=http -p 3010:3010 npi-providers-mcp-server

The Dockerfile defaults to HTTP transport, stateless session mode, and logs to /var/log/npi-providers-mcp-server. OpenTelemetry peer dependencies are installed by default — build with --build-arg OTEL_ENABLED=false to omit them.

Project structure

Development guide

See CLAUDE.md/AGENTS.md for development guidelines and architectural rules. The short version:

• Handlers throw, framework catches — no try/catch in tool logic
• Use ctx.log for request-scoped logging, ctx.state for tenant-scoped storage
• Register new tools and resources in the createApp() arrays
• Wrap external API calls: validate raw → normalize to domain type → return output schema; never fabricate missing fields

Data attribution

Provider data from the CMS NPPES NPI Registry (public domain). The bundled specialty codes are the NUCC Health Care Provider Taxonomy, © American Medical Association on behalf of the National Uniform Claim Committee (NUCC), redistributed unmodified beyond formatting under the NUCC permission. See NOTICE.

Contributing

Issues are welcome. Run checks and tests before submitting:

bun run devcheck
bun run test

License

Apache-2.0 — see LICENSE for details.