---

Tools

Three tools covering the provider directory — search the registry, decode an NPI to its full record, and resolve plain-language specialties through the bundled taxonomy:

Tool	Description
npi_search_providers	Search the NPPES registry by name, organization, location, provider type, and specialty. Plain-language specialties resolve through the bundled NUCC taxonomy before searching.
npi_get_provider	Fetch the complete NPPES record for up to 10 NPIs — taxonomies, addresses, credentials, identifiers, endpoints, and status.
npi_lookup_taxonomy	Resolve, fetch, or browse the NUCC Healthcare Provider Taxonomy — fully offline.

npi_search_providers

Search the registry for individual practitioners and organizations, with specialty resolution and honest pagination disclosure.

• Search by name_search shortcut, explicit first_name / last_name, organization_name, city / state / postal_code, and provider_type (individual / organization)
• Plain-language specialty (e.g. "cardiologist") resolves through the bundled NUCC taxonomy to the registry's exact descriptions before searching; the resolved taxonomy is echoed back so you can see what was actually searched
• taxonomy_description escape hatch for callers who already hold an exact NUCC description (mutually exclusive with specialty)
• Trailing-wildcard (*) name matching, with the registry's ≥2-leading-character rule documented inline
• Discloses that the returned count is the page size — never a grand total — and that only the first 1200 matches are reachable, steering broad queries toward narrower filters

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npi_get_provider

Decode one or more NPIs into fully populated provider profiles — the tool to turn an NPI from a claim, prescription, or another health data source into a known provider.

• Batch fetch up to 10 NPIs per call; the 10-digit format is validated before any API call
• Returns every taxonomy (with its primary flag, license number and state), all practice and mailing addresses, credential, sex, sole-proprietor flag, enumeration and last-updated dates, secondary identifiers (Medicaid, etc.), and FHIR/Direct endpoints
• Partial-success reporting — well-formed NPIs with no registry record (deactivated or never enumerated) land in notFound rather than failing the whole call

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npi_lookup_taxonomy

Resolve and browse the NUCC Healthcare Provider Taxonomy — the specialty code set NPPES uses — fully offline from the bundled code set.

• resolve — turn a plain-language specialty into matching taxonomy codes and canonical descriptions (the value the search tools filter on); plain-language phrasing ("heart doctor", "eye doctor") and common abbreviations ("ent", "obgyn") resolve to the right physician entry
• get — return the full entry for an exact taxonomy code
• browse — walk the hierarchy (grouping → classification → specialization), filterable by grouping and by NPI section (Individual/NPI-1 vs Non-Individual/NPI-2)

resolve and browse cap results at limit (≤50) and disclose truncated; page past the cap with skip (raise it by limit each call, same query/filters) so every bundled entry stays reachable. skip is ignored for get.

Resources and prompts

Type	Name	Description
Resource	npi://provider/{npi}	A single provider's full decoded record by NPI — the resource twin of npi_get_provider.
Resource	npi://taxonomy/{code}	A single NUCC taxonomy entry by code — the resource twin of npi_lookup_taxonomy mode get.

All resource data is also reachable via tools. The resources are convenience twins for resource-capable clients; tool-only clients lose nothing.

Features

Built on @cyanheads/mcp-ts-core:

• Declarative tool and resource definitions — single file per primitive, framework handles registration and validation
• Unified error handling — handlers throw, framework catches, classifies, and formats
• Pluggable auth: none, jwt, oauth
• Swappable storage backends: in-memory, filesystem, Supabase, Cloudflare KV/R2/D1
• Structured logging with optional OpenTelemetry tracing
• STDIO and Streamable HTTP transports

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 879-code Healthcare Provider Taxonomy (v25.0) 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, with the 1200-match reachable ceiling surfaced when a broad query is capped
• Graceful partial failure — npi_get_provider returns per-NPI found / notFound rows instead of failing the whole batch when some NPIs are deactivated or never enumerated

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 install

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 v1.3.2 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.

Variable	Description	Default
NPPES_API_BASE_URL	NPPES NPI Registry API base URL. Override for a private mirror or testing.	https://npiregistry.cms.hhs.gov/api
NPPES_TIMEOUT_MS	Per-request HTTP timeout for NPPES calls, in milliseconds.	15000
MCP_TRANSPORT_TYPE	Transport: stdio or http.	stdio
MCP_HTTP_PORT	Port for the HTTP server.	3010
MCP_AUTH_MODE	Auth mode: none, jwt, or oauth.	none
MCP_LOG_LEVEL	Log level (RFC 5424).	info
STORAGE_PROVIDER_TYPE	Storage backend.	in-memory
OTEL_ENABLED	Enable OpenTelemetry instrumentation (spans, metrics, completion logs).	false

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

Running the server

Local development

• Build and run:

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

• Run checks and tests:

  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

Directory	Purpose
src/index.ts	createApp() entry point — registers tools and resources, inits services.
src/config	Server-specific environment variable parsing and validation with Zod.
src/mcp-server/tools	Tool definitions (*.tool.ts).
src/mcp-server/resources	Resource definitions (*.resource.ts).
src/services/nppes	NPPES NPI Registry API client — query building, Errors[]-on-200 detection, normalization.
src/services/taxonomy	Bundled NUCC taxonomy service — in-memory index for resolve / get / browse.
tests/	Unit and integration tests mirroring src/.

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

Contributing

Issues and pull requests are welcome. Run checks and tests before submitting:

bun run devcheck
bun run test

License

Apache-2.0 — see LICENSE for details.

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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.