aaronbrezel/mcp-census

title: 🏘️ Mcp Census emoji: 🏘️ colorFrom: yellow colorTo: indigo sdk: gradio sdk_version: 5.34.0 python_version: 3.13 app_file: gradio_app.py pinned: false short_description: MCP server leveraging U.S. Census Bureau tooling

mcp-census

A work-in-progress MCP server leveraging U.S. Census Bureau tooling for LLM interoperability.

Though we recommend installing this server locally, a deployed census MCP server is available at https://abrezey-mcp-census.hf.space/gradio_api/mcp/sse. Pushes to the main branch of this repo will trigger a redeployment of this resource via GitHub Actions.

This repo was originally built for the Gradio/Hugging Face Agents MCP Hackathon.

Quickstart

Right now, we recommend using mcp-census in conjunction with an MCP Client running a strong foundation model like Claude Desktop or Cursor.

Remote

To connect Claude Desktop to the mcp-census server hosted on Hugging Face (requires Claude Pro tier and above):

Local

To locally run mcp-census directly in Claude Desktop (you'll need uv), modify your claude_desktop_config.json:

{
  "mcpServers": {
    "mcp-census": {
      "command": "uvx",
      "args": [
        "--env-file",
        "/path/to/mcp-census/.env",
        "/path/to/mcp-census",
        "mcp-census"
      ]
    }
  }
}

If you prefer to run your own client application and LLM, check out Local Agent Quickstart.

Example usage

What is the population of Hennepin County, MN for those who are 65 and older?

https://github.com/user-attachments/assets/73f53b8a-be57-4bdd-a105-3676f84730de

What is the racial/ethnic breakdown of Yolo County?

https://github.com/user-attachments/assets/23c2c9c9-ce79-4fb1-a393-6cd10bdf1eff

Lookup data from the US 2020 Decennial Census and provide a CSV containing data about the number of housing units, total population, and median age for all counties in New York State. For the column containing the county identifier, please provide a complete FIPS containing the state and county as a joined value.

https://github.com/user-attachments/assets/8c9fac39-0beb-4f27-97b2-430cb4b20465

Local MCP server local development

We suggest using uv to manage dependencies, but you can install the required packages directly from the

Linting and formatting provided by ruff and pre-commit

uv run pre-commit install

The mcp package provides a handy dev server where you can test functions via UI.

npx @modelcontextprotocol/inspector uv run mcp-census

API Keys

mcp-census requires an API key in order to request data from U.S. Census Bureau servers.

cp .env.example .env

Then fill out your API keys

To request a census API key, visit https://api.census.gov/data/key_signup.html. To request a Hugging Face token, visit https://huggingface.co/docs/hub/security-tokens.

The MCP server does not require a Hugging Face token, though it becomes useful during agent development.

Gradio MCP server local development

uv run --group gradio-deployment python gradio_app.py

Assuming you have no other Gradio applications running, this will serve your MCP server at http://localhost:7860/gradio_api/mcp/sse

To update dependencies for the Gradio deployment

uv export --group gradio-deployment > requirements.txt

Note: for now you have to remove the -e . that the above command generates.

Local Agent Quickstart

You need to start all three applications (MCP server, Agent, Phoenix) for the system to work at the moment.

Agent (and MCP client)

uv run --group agent python agent.py

Observability

When debugging Agents, observability is key. The agent is currently configured to send logs to a phoenix server.

uv run python -m phoenix.server.main serve

The agent will not work without this server running.

MCP architecture

Feature roadmap

Evaluation

• Create a benchmark with which to evaluate MCP server utilization by host application
• Improve MCP feature reliability via Unit Testing

MCP Server

• The Census Bureau publishes myriad documentation. Enabling semantic retrieval via RAG should provide agents with information to better respond to user queries.
• Experiment with MCP "Prompts" to better guide LLM question answering
  • This should include strong citation of process
• Experiment with MCP "Ellicitation" to make question answering process more interactive/guided.

MCP Distribution

• MCP server installation through desktop extension.