soi-mcp

IRS income & tax statistics by ZIP code, inside your agent. An MCP server that lets an LLM pull the income distribution, tax, credits, and deductions of any U.S. ZIP straight from the IRS Statistics of Income (SOI) — built on Anthropic's official mcp Python SDK.

All tools are read-only and the data is public domain (a U.S. government work) — no API key required. The dataset is downloaded once into a local SQLite store and served offline.

Status: published — uvx mcpwright-soi (PyPI) and listed in the official MCP Registry as io.github.mcpwright/soi-mcp. 10 tools, working today (see below). The IRS SOI ZIP release lags ~2–3 years; the latest available year (currently Tax Year 2022) loads by default, and older years are one refresh <year> away. See the roadmap for what's next.

Tools

All dollar amounts are returned in whole USD (the source reports thousands). Counts are numbers of returns, rounded by the IRS to the nearest 10.

Related MCP server: mcp-census

Install

Requires Python 3.12+. The zero-clone way to run it (the PyPI package is mcpwright-soi; the command, server, and tools are all "soi"):

uvx mcpwright-soi

The first tool call downloads the latest SOI ZIP file (~200 MB) into a local SQLite store under your OS cache directory and serves everything offline thereafter. To pre-load (or to pick a specific tax year) without waiting for the first query:

uvx mcpwright-soi setup            # download the latest available year
uvx mcpwright-soi refresh 2021     # re-pull a specific older year for comparison

Claude Code

claude mcp add soi -- uvx mcpwright-soi

Claude Desktop

Add to claude_desktop_config.json:

{
  "mcpServers": {
    "soi": { "command": "uvx", "args": ["mcpwright-soi"] }
  }
}

OpenAI Agents SDK (Python)

It's a standard MCP server, so it works with any MCP-capable client — not just Claude. With the OpenAI Agents SDK:

from agents import Agent, Runner
from agents.mcp import MCPServerStdio

async def main():
    async with MCPServerStdio(
        name="soi",
        params={"command": "uvx", "args": ["mcpwright-soi"]},
    ) as soi:
        agent = Agent(
            name="Analyst",
            instructions="Use the SOI tools for IRS income and tax data by ZIP.",
            mcp_servers=[soi],
        )
        result = await Runner.run(
            agent, "What's the income distribution of ZIP 90210 vs 10001?"
        )
        print(result.final_output)

Any other MCP client (Cursor, VS Code, Cline, Goose, Zed, …)

They all launch a stdio MCP server the same way — point yours at:

{
  "mcpServers": {
    "soi": { "command": "uvx", "args": ["mcpwright-soi"] }
  }
}

Hosted chat connectors (e.g. ChatGPT connectors) expect a remote MCP server over Streamable HTTP; mcpwright-soi runs locally over stdio.

Storage: the dataset lives in a SQLite file under your OS cache dir (override with the SOI_MCP_STORE env var). Delete it any time; setup / refresh rebuilds it.

A note on suppression: the IRS excludes ZIPs with fewer than 100 returns (folding them into a "99999" bucket) and suppresses line items with fewer than 20 returns. Summed ZIP totals can therefore slightly understate reality and won't exactly equal the state total. All figures are aggregates of filed returns, not a population census.

Develop

git clone https://github.com/mcpwright/soi-mcp && cd soi-mcp
uv sync
uv run pytest                                          # tests (mocked download + seeded SQLite)
uv run ruff check src/ && uv run ruff format --check src/   # lint + format
uv run mypy                                            # strict type checking
uv run mcp dev src/soi_mcp/server.py                   # poke the tools in the MCP Inspector

Roadmap

• lookup_zip / get_income / get_agi_distribution — the income backbone

• get_tax / get_credits / get_deductions / get_filing_status — the tax side

• compare_zips — rank ZIPs by a metric

• get_state_totals — state rollups from the IRS 00000 row

• get_soi_field — raw-field escape hatch

• setup / refresh [year] — download once, re-pull or pick an older tax year

• Publish to PyPI (mcpwright-soi) + the official MCP Registry (io.github.mcpwright/soi-mcp)

• Multi-year queries in one call (trend a ZIP across tax years)

Privacy

soi-mcp runs entirely on your machine. It collects, stores, or transmits no personal data — no accounts, no tracking, no telemetry. Its only outbound requests go to the U.S. IRS static file host (www.irs.gov/pub/irs-soi) to download the public SOI ZIP-code CSV; no API key is needed and nothing about your queries leaves your machine. The downloaded dataset is cached on disk as a local SQLite file (under your OS cache dir, or SOI_MCP_STORE); delete it any time.

Full policy: https://mcpwright.com/privacy/

Questions & feedback

• Questions, ideas, or "could it do X?" → Discussions

• Bugs & concrete feature requests → Issues

Contributions welcome — and if you build something with it, I'd love to hear about it.

Part of mcpwright · built by Devender Gollapally