npi-verify

A small, typed Python client and MCP server for the public CMS NPPES NPI Registry.

What it is

npi-verify looks up and searches United States healthcare providers against the National Plan and Provider Enumeration System (NPPES) NPI Registry. NPPES is the authoritative registry published by the Centers for Medicare and Medicaid Services (CMS). Every clinician and healthcare organization that bills US payers has an NPI, and the registry is the source of truth for that identity.

The package gives you two things:

1. A typed, dependency-light Python client that parses NPPES JSON into frozen dataclasses.

2. An MCP (Model Context Protocol) server that exposes the same lookups as tools an AI agent can call.

Related MCP server: NPI Registry MCP Server

Why

If you are building anything that touches the healthcare workforce, you eventually need to confirm that a provider is real and that the identity you were handed matches the public record. Checking the NPI against the CMS source of truth is the cheapest, most defensible verification step available, and it requires no credentials. This package makes that check a one-line call and a reusable agent tool.

The client validates the NPI offline before it ever hits the network, using the same Luhn checksum (over the 80840 issuer prefix) that NPPES itself uses, so malformed input fails fast and for free.

Public CMS data, no PHI

The NPPES NPI Registry is free, public, and requires no authentication. It returns provider demographic data only: names, NPIs, taxonomies, practice addresses, and enumeration status. It contains no protected health information (PHI). This package sends no credentials and stores nothing.

Install

pip install npi-verify

To use the MCP server, install the optional mcp extra:

pip install "npi-verify[mcp]"

From source:

git clone https://github.com/gm4prezi/npi-verify.git
cd npi-verify
pip install -e ".[dev]"

Client usage

Look up a single provider by NPI:

from npi_verify import NPIClient

with NPIClient() as client:
    provider = client.lookup_npi("1234567893")

if provider is None:
    print("No provider with that NPI.")
else:
    print(provider.name, provider.credential)
    print(provider.taxonomy.description)
    print(provider.primary_address.city, provider.primary_address.state)

Search by name, state, taxonomy, or organization:

from npi_verify import NPIClient

with NPIClient() as client:
    providers = client.search(
        last_name="Rivera",
        state="GA",
        taxonomy_description="Internal Medicine",
        limit=10,
    )

for provider in providers:
    print(provider.npi, provider.name, provider.entity_type)

Validate an NPI without any network call:

from npi_verify import is_valid_npi, validate_npi

is_valid_npi("1234567893")   # True
is_valid_npi("1234567890")   # False (bad checksum)
validate_npi("0000000000")   # raises ValueError

Errors

• lookup_npi and validate_npi raise ValueError for a structurally invalid NPI.

• A not-found lookup returns None. An empty search returns [].

• Network failures, timeouts, and NPPES query errors raise NPIRegistryError.

MCP usage

The package ships an MCP server over stdio that exposes two tools, lookup_npi and search_providers, both wired to the client above.

Run it directly:

npi-verify-mcp
# or
python -m npi_verify.mcp_server

Register it with an MCP client (for example, Claude Desktop) by adding this to your MCP configuration:

{
  "mcpServers": {
    "npi-verify": {
      "command": "npi-verify-mcp"
    }
  }
}

If you prefer not to install the console script, point the config at the module:

{
  "mcpServers": {
    "npi-verify": {
      "command": "python",
      "args": ["-m", "npi_verify.mcp_server"]
    }
  }
}

Data model

lookup_npi and search return frozen Provider dataclasses:

Development

pip install -e ".[dev]"
pytest

The default test run mocks all HTTP, so it makes no network calls and is safe for CI. A single live smoke test against the real NPPES API is marked live and is skipped by default. Run it explicitly with:

pytest -m live

License

MIT. See LICENSE.