🏛️ irs-taxpayer-mcp

An open-source tax estimation and planning assistant for US individual taxpayers using Model Context Protocol.

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⚠️ Disclaimer: This tool provides estimates for educational and informational purposes only. It does not constitute tax, legal, or financial advice. Always consult a qualified tax professional.

Legal Notice: This software is provided "as is" without warranty of any kind. The authors and contributors are not tax professionals, CPAs, enrolled agents, or attorneys. No attorney-client, CPA-client, or fiduciary relationship is created by using this software. Tax laws change frequently and vary by jurisdiction. The calculations may contain errors, omissions, or may not reflect the most recent legislative changes. You are solely responsible for your tax filing decisions. The authors disclaim all liability for any damages arising from the use of this software. See DISCLAIMER.md for full legal notice.

Why This MCP?

Tax season is stressful. You're juggling W-2s, 1099s, deductions, credits, and trying to figure out if you should itemize or take the standard deduction. You Google "SALT deduction limit 2025" and get 10 conflicting articles.

This MCP server puts a tax-aware assistant inside your AI chat. Ask about a supported tax scenario in plain language and get deterministic estimates from versioned TY2024 through TY2026 data. Calculations run locally on your machine. No IRS login or SSN is required.

It includes OBBB provisions modeled for TY2025, federal brackets, selected credits and deductions, and explicitly supported state-tax paths. Unsupported state calculations fail closed instead of applying a rough top-rate estimate.

🔒 Privacy Architecture

⚡ Getting Started

Step 1: Add to your AI assistant

Add this to your MCP client configuration:

Claude Desktop (~/Library/Application Support/Claude/claude_desktop_config.json):

{
  "mcpServers": {
    "irs-taxpayer": {
      "command": "npx",
      "args": ["-y", "irs-taxpayer-mcp"]
    }
  }
}

Kiro (.kiro/settings/mcp.json):

{
  "mcpServers": {
    "irs-taxpayer": {
      "command": "npx",
      "args": ["-y", "irs-taxpayer-mcp"]
    }
  }
}

Cursor: same format in Cursor's MCP settings.

Step 2: Restart your AI assistant

After saving the config, restart the app. The MCP server will auto-download and connect.

Step 3: Start asking tax questions

That's it. Just chat naturally:

• "Calculate my federal tax: $150k income, married filing jointly, 2 kids"
• "Compare California vs Texas vs Washington for $200k income"
• "I'm a freelancer making $80k: what are my quarterly estimated taxes?"
• "What tax credits am I eligible for? AGI $60k, single, one child"
• "Should I itemize or take the standard deduction? I pay $15k in mortgage interest and $12k in state taxes"
• "Explain the Backdoor Roth IRA strategy"
• "How much is the EITC for a family of 4 earning $35k?"
• "I exercised ISOs this year: will I owe AMT?"
• "Help me plan my year-end tax moves. I have a 401k and HSA."

Alternative: Docker

docker build -t irs-taxpayer-mcp .
docker run -i irs-taxpayer-mcp

Alternative: Streamable HTTP Transport

npx irs-taxpayer-mcp --http --port 3000
# MCP endpoint: http://127.0.0.1:3000/mcp
# Health check: http://127.0.0.1:3000/health

HTTP mode is stateless and binds only to a loopback host by default. Browser requests must use an exact allowed Origin. Add a trusted browser Origin with a repeatable flag:

npx irs-taxpayer-mcp --http \
  --allowed-origin https://trusted-client.example

The legacy --sse flag remains a deprecated alias for --http. The old /sse and /messages endpoints are not exposed.

🛠️ Tools (44)

All tools use the current MCP registerTool API. Each advertises read-only annotations and an output schema, and returns both human-readable text and structuredContent. Error results include a stable error code, message, and recovery suggestion.

The 1.0 flagship generate_tax_plan workflow returns domain structured results, assumptions, official source provenance, a calculation trace, and explicit unsupported boundaries. It performs no network requests, persistence, or telemetry. Unsupported tax years, state profiles, and required worksheet facts fail closed. See Local Tax Planner 1.0 Contract.

Federal Tax Calculations

Deduction Analysis

Tax Credits

Retirement & Strategy

Tax Planning & Scenarios

State Taxes

IRS Information

OBBB Act (2025) Tools

Full Reports & Analysis

Guidance & Feedback

📊 Tax Year Coverage

TY2024

Supported historical calculation year using IRS Revenue Procedure 2023-34. Standard deduction $14,600 (single) / $29,200 (MFJ). CTC $2,000. SALT cap $10,000.

TY2025

Reflects OBBB signed July 4, 2025:

• Standard deduction: $15,750 (single) / $31,500 (MFJ) / $23,625 (HoH)
• Child Tax Credit: $2,200 per child (up from $2,000)
• SALT cap: $40,000 for AGI ≤ $500K (was $10,000)
• New deductions: tips ($25K), overtime ($12.5K), senior bonus ($6K age 65+), auto loan interest ($10K)
• 401k catch-up: $11,250 for ages 60-63 (SECURE 2.0)

TY2026

Uses IRS Revenue Procedure 2025-32 and the SSA 2026 contribution and benefit base:

• Standard deduction: $16,100 (single) / $32,200 (MFJ) / $24,150 (HoH)
• Child Tax Credit: $2,200 per qualifying child, with up to $1,700 refundable
• SALT cap: $40,400 for MAGI up to $505,000; $20,200 and $252,500 for MFS
• Social Security wage base: $184,500
• Updated ordinary, capital-gains, EITC, and AMT thresholds

Supported Scope and Boundaries

This project is a deterministic estimation and planning engine, not tax preparation or filing software.

• Federal estimates cover the modeled TY2024 through TY2026 inputs exposed by each tool. They do not implement every Form 1040 line, schedule, election, limitation, carryforward, or dependency rule.
• State reference information covers all 50 states and DC. Numeric estimates require an exact tax-year profile: TY2024 supports AK, CA, FL, NV, SD, TN, TX, and WY; TY2025 and TY2026 support AK, FL, NH, NV, SD, TN, TX, and WY. California TY2024 supports single and married brackets. Other state-year and filing-status paths return an error.
• State calculations do not yet model part-year or nonresident allocation, every local tax, or separate HoH and MFS brackets.
• QBI, AMT, audit-risk, retirement, relocation, and multi-year outputs are planning estimates with documented simplifications.
• Refund projections depend only on the inputs and refundable credits modeled by the selected tool. They are not an IRS refund determination.
• The server does not generate a tax return, sign a return, transmit MeF data, or provide filing eligibility validation.

See ROADMAP.md for the remaining work toward a filing-grade federal return engine.

🧮 Calculation Engine

Numeric regression tests cite IRS Revenue Procedures, IRC sections, and relevant legislation. Reference and planning tools may summarize rules that are not fully represented in the calculation engine.

🏗️ Build from Source

Requires Node.js 20 or later.

git clone https://github.com/dma9527/irs-taxpayer-mcp.git
cd irs-taxpayer-mcp
npm install
npm run build
npm start          # stdio mode
npm run dev        # development mode (tsx)

🐛 Found a Bug?

• Calculation error or incorrect data? Open an issue: include the tool name, tax year, a rounded or synthetic example, and the expected result. Do not post taxpayer PII.
• Planner use case or product gap? Use the Planner Feedback form. Do not include taxpayer PII or a real tax return.
• Questions or discussion? GitHub Discussions
• Want to contribute? See CONTRIBUTING.md

🤝 Contributing

Contributions welcome. Please ensure:

• All tests pass (npm test)
• Build succeeds (npm run build)
• No any types in TypeScript
• Data changes include IRS source citations

See CONTRIBUTING.md for full guidelines.

📄 License

MIT