Arlet

Connect U.S. Census Bureau to Claude Code

Query U.S. Census Bureau directly from Claude Code. Arlet links the two through one MCP connection and takes care of API keys.

This server connects your AI client to the US Census Bureau data API, which publishes the country's demographic and economic baseline statistics. The Census variable system is famously intricate (tables like B19013, variables like B19013_001E, geography codes like state:06); this server wraps it in a three-step flow that an AI can follow reliably.

Key features:

  • search_tables: find statistical tables by keyword within a dataset - 'median household income' resolves to table B19013. Defaults to the American Community Survey 5-year estimates (acs/acs5), the dataset with the finest geographic detail.
  • list_table_variables: list a table's variables with human-readable labels. By default only estimate variables are shown, hiding the margin-of-error and annotation columns that usually just add noise.
  • get_data: fetch values for chosen variables and a geography in the Census 'level:codes' form (us:1, state:06, county:* within a state, place:*, ...). The raw array-of-arrays response is converted to named records, and geography names are always included.

Other datasets and years are reachable through the dataset/vintage parameters (acs/acs1, dec/pl decennial redistricting, cbp County Business Patterns, ...).

Arlet obtains and manages the API key, so there is nothing for you to sign up for or configure - just switch the server on. (The key's rate limit is shared across Arlet users.)

How to connect U.S. Census Bureau to Claude Code

  1. 1

    In the Arlet dashboard, open Data tools, find U.S. Census Bureau and switch it on. No API key setup is needed.

  2. 2

    In your terminal, run claude mcp add --transport http arlet https://mcp.arlet.dev/mcp/ to add Arlet as an MCP server.

  3. 3

    Start Claude Code, run /mcp, select arlet and click Authenticate.

  4. 4

    Your browser opens. Sign in with Google and click Allow on the consent screen. The connection is complete.

The connection is per user and works across every project on the same machine.

Use U.S. Census Bureau with other AI clients