irs-taxpayer-mcp

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# 🏛️ irs-taxpayer-mcp

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

[![License: MIT](https://img.shields.io/badge/License-MIT-blue.svg)](LICENSE)
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[![npm](https://img.shields.io/npm/v/irs-taxpayer-mcp.svg)](https://www.npmjs.com/package/irs-taxpayer-mcp)
[![TypeScript](https://img.shields.io/badge/TypeScript-5.9-blue.svg)](https://www.typescriptlang.org/)
[![MCP](https://img.shields.io/badge/MCP-Compatible-green.svg)](https://modelcontextprotocol.io)

[English](README.md) | [中文](docs/README_zh.md) | [Español](docs/README_es.md) | [日本語](docs/README_ja.md)

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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](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

| Layer                | Design                                              |
| -------------------- | --------------------------------------------------- |
| All tax calculations | 100% local execution: zero network calls           |
| User data storage    | Stateless: nothing saved between calls             |
| Authentication       | Zero credentials: no SSN, no IRS login             |
| Public IRS data     | Bundled and versioned locally: zero runtime network calls |
| Telemetry            | None: no analytics, no tracking, no logging        |
| Source code          | Fully open-source (MIT): audit every calculation   |

## ⚡ 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`):

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

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

```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

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

### Alternative: Streamable HTTP Transport

```bash
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:

```bash
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.

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## 🛠️ 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](docs/PLANNER_CONTRACT.md).

### Federal Tax Calculations

| Tool                       | What it does                                                                                                                         |
| -------------------------- | ------------------------------------------------------------------------------------------------------------------------------------ |
| `calculate_federal_tax`    | Full federal tax with bracket breakdown, AMT, NIIT (3.8%), Additional Medicare Tax (0.9%), QBI deduction, SE tax, capital gains, CTC |
| `get_tax_brackets`         | Tax brackets and standard deduction by filing status and year                                                                        |
| `compare_filing_statuses`  | Side-by-side comparison of all 4 filing statuses for the same income                                                                 |
| `estimate_quarterly_tax`   | Estimated quarterly payments (1040-ES) with safe harbor guidance                                                                     |
| `calculate_total_tax`      | Combined federal + state tax in one call, with take-home pay and monthly income                                                      |
| `calculate_w4_withholding` | Per-paycheck withholding estimate with step-by-step W-4 form recommendations                                                         |

### Deduction Analysis

| Tool                   | What it does                                                                                |
| ---------------------- | ------------------------------------------------------------------------------------------- |
| `list_deductions`      | Browse all deductions with eligibility rules, limits, and forms                             |
| `standard_vs_itemized` | Compare standard vs itemized with year-specific SALT cap ($10K for TY2024, $40K for TY2025) |

### Tax Credits

| Tool                       | What it does                                                              |
| -------------------------- | ------------------------------------------------------------------------- |
| `list_tax_credits`         | 20+ federal credits: CTC, EITC, AOTC, EV, solar, saver's credit, and more |
| `check_credit_eligibility` | Quick screening based on your income, family, and situation               |
| `calculate_eitc`           | Precise EITC calculation with phase-in/plateau/phase-out for 0-3 children |

### Retirement & Strategy

| Tool                      | What it does                                                                   |
| ------------------------- | ------------------------------------------------------------------------------ |
| `get_retirement_accounts` | IRA, Roth, 401k, SEP, Solo 401k, HSA, 529: limits, tax treatment, tips        |
| `get_retirement_strategy` | Backdoor Roth, Mega Backdoor, Roth Conversion Ladder, Tax Loss/Gain Harvesting |

### Tax Planning & Scenarios

| Tool                             | What it does                                                                                                    |
| -------------------------------- | --------------------------------------------------------------------------------------------------------------- |
| `generate_tax_plan`              | Privacy-first local plan with structured results, assumptions, sources, trace, and explicit boundaries         |
| `get_tax_planning_tips`          | Personalized year-end optimization: 401k maxing, HSA, Roth conversion, tax-loss harvesting, charitable bunching |
| `compare_tax_years`              | Compare TY2024 vs TY2025 to see how bracket changes and OBBB affect your tax                                    |
| `estimate_self_employment_tax`   | Full SE tax breakdown: Schedule C profit, SE tax, QBI deduction, quarterly payments, SEP/Solo 401k limits       |
| `analyze_mortgage_tax_benefit`   | Mortgage interest + property tax deduction analysis with year-specific SALT cap                                 |
| `analyze_education_tax_benefits` | AOTC vs Lifetime Learning Credit comparison, student loan deduction, 529 plan guidance                          |

### State Taxes

| Tool                        | What it does