Arlet

Connect U.S. Census Bureau to Codex

Query U.S. Census Bureau directly from Codex. 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 Codex

  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 codex mcp add arlet --url https://mcp.arlet.dev/mcp/ to add Arlet as an MCP server.

  3. 3

    Codex detects OAuth support and opens your browser. Sign in with Google and click Allow on the consent screen.

  4. 4

    Once connected, both the CLI and the IDE extension can call Arlet tools (the configuration is shared).

If the browser does not open, run codex mcp login arlet to redo the authentication.

Use U.S. Census Bureau with other AI clients