US individual tax planning, TY2024 to TY2026

Know the number before December 31.

Should you convert to Roth this year? Sell winners in the 0% bracket? Top up the 401(k)? Get the exact figure from IRS tables, with the work shown, and keep your finances out of a chatbot.

# one-time install, then everything runs locally
$ npm install --global irs-taxpayer-mcp
$ irs-taxpayer-mcp intake --output facts.json
$ irs-taxpayer-mcp plan --facts facts.json

Open source (MIT). Estimates for planning, not filing software.

LOCAL TAX PLAN FOR TY2026

Synthetic household: married filing jointly, $185,000 W-2, $12,000 long-term gains, two children.

Adjusted gross income$197,000
Taxable income$164,800
Federal tax after refundable credits$20,440
Employee FICA$14,122
State tax$0
Total modeled tax$34,562
Take-home income$162,438

PRIVACY. Calculated directly by the local deterministic engine. No model, network request, persistence, or telemetry was used.

modelInvoked: falseno model, no network

Add --json for assumptions, official sources, a calculation trace, and privacy.modelInvoked.

Decisions it works out

Each answer comes from a calculation you can re-run and check. Examples use synthetic TY2026 numbers.

Question	Tool	What you get
What does a Roth conversion cost this year?	`simulate_tax_scenario`	Married filing jointly on $150,000: a $30,000 conversion raises federal tax from $15,340 to $21,940. That is $6,600, a flat 22%.
Can I sell winners at 0% tax?	`optimize_capital_gains`	Your room left in the 0% bracket, and a warning when a loss would only cancel tax-free gains.
Itemize or take the standard deduction?	`standard_vs_itemized`	The SALT cap, charitable floor, and non-itemizer charitable deduction applied for the year you pick.
What do I owe each quarter as a freelancer?	`estimate_quarterly_tax`	Form 1040-ES amounts with safe harbor guidance.
Is my paycheck withholding on track?	`analyze_paycheck`	A projected annual tax that counts credits, and suggested W-4 changes.
Will moving states save money?	`analyze_relocation_taxes`	Exact-year state comparison. A state without a verified profile returns an error, not a guess.

Two ways in, and the difference matters

Both run the same engine. They differ in who else sees your numbers.

Direct command line

Private by construction

Starts no MCP connection and calls no model.
Makes no tax-data network request and sends no telemetry.
Reads a strict, versioned JSON file. Names, SSNs, addresses, and account numbers are rejected.
New files are created with mode 0600 on macOS and Linux.

irs-taxpayer-mcp template --output facts.json
irs-taxpayer-mcp validate --facts facts.json
irs-taxpayer-mcp plan --facts facts.json --json

MCP server, 45 tools

For your AI assistant

Works with Claude, Kiro, Cursor, and other MCP clients.
The engine still calculates locally and stores nothing.
Plans report modelInvoked: true, because your assistant may have seen the facts.
Ask in plain language and get the same deterministic numbers.

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

Be precise about privacy. With a cloud-hosted MCP client, your prompts and tool arguments go to that client's model provider. If that matters, use the direct command line.

Built to say "no"

A tax tool earns trust by what it refuses to do.

It fails closed

An unsupported tax year, state, or missing required fact returns an error. It never falls back to a rough top-rate guess.

It is not filing software

It does not prepare, sign, or transmit a return, and it does not model every form, schedule, or election.

It shows its work

Every plan lists its assumptions, the official IRS and SSA sources it used, and a calculation trace. A model never does the arithmetic.

Questions

Which years and states are covered?

Federal estimates cover TY2024 through TY2026 for the inputs each tool exposes. Reference data covers all 50 states and DC, but numeric state estimates need an exact tax-year profile. The README lists the supported state-year paths.

Do I need an IRS login or my SSN?

No. The tool needs no account and no identifying information. The facts file format rejects names, SSNs, addresses, employer IDs, and account numbers.

Can I trust the numbers?

Treat them as planning estimates. Tests cite IRS revenue procedures and Internal Revenue Code sections, and the same inputs always give the same answer. If you find a wrong number, report it with a rounded or synthetic example and no personal details.

Does it replace a tax professional?

No. It supports planning decisions and does not give tax, legal, or financial advice. Check important decisions with a qualified professional.