Census (ACS by ZIP) MCP server

census-mcp

<!-- mcp-name: io.github.mcpwright/census-mcp -->

U.S. Census data by ZIP code, inside your agent. An MCP server that lets an LLM look up income, demographics, housing, and education for any ZIP — built on Anthropic's official mcp Python SDK.

All tools are read-only. Data is the U.S. Census Bureau's American Community Survey (ACS) 5-year release — bulk-downloaded once into a local store, then served offline. A free Census API key is required for the one-time download.

Status: published (v0.1.2) — uvx mcpwright-census (PyPI) and listed in the official MCP

Registry as io.github.mcpwright/census-mcp. All 8 tools below are live and unit-tested, verified

end-to-end against the live ACS 5-year release (vintage 2024 at the time of writing — the

server auto-detects the latest). Part of the

mcpwright suite.

Tools

ZIP ≈ ZCTA (ZIP Code Tabulation Area): they mostly coincide, but ~2% of ZIPs (PO-box-only / non-residential) have no ZCTA and will return an error. All ACS figures are 5-year estimates.

findzips is the reverse direction (place → ZIPs). It's approximate: ZCTAs don't nest inside places, so a ZIP can span several places and vice versa — read each match's coveragepct and pass a state to disambiguate same-named places (e.g. Cambridge, MA vs OH). It's built on the public 2020 Census ZCTA-to-Place relationship file (2020 geography; no API key needed for it).

Install

Requires Python 3.12+ and a free Census API key (set CENSUSAPIKEY). The PyPI package is mcpwright-census; the command, server, and tools are all "census".

export CENSUS_API_KEY=your-free-key
uvx mcpwright-census setup     # one-time: bulk-download the ACS dataset into a local store

Claude Code

claude mcp add census -e CENSUS_API_KEY=your-free-key -- uvx mcpwright-census

Claude Desktop

Add to claudedesktopconfig.json:

{
  "mcpServers": {
    "census": {
      "command": "uvx",
      "args": ["mcpwright-census"],
      "env": { "CENSUS_API_KEY": "your-free-key" }
    }
  }
}

First run downloads the full ACS dataset (~33k ZCTAs) into a local SQLite store under

your OS cache dir, so every later lookup is instant and offline. Run mcpwright-census setup

ahead of time, or let the server download lazily on first use. mcpwright-census refresh

re-pulls when a new ACS vintage is published. Override the store location with

CENSUSMCPSTORE.

Develop

Shortened. The full README is on GitHub.