MCP server

Pass-through tax rules

A read-only rules server for agents. It answers elective pass-through entity tax, the federal SALT deduction cap, and bonus-depreciation conformity from dated files. Each answer cites a statute or a revenue-department page. A state or year that is not in the files comes back as not covered.

Informational. Not tax advice.

Endpoint

Streamable HTTP. No API key.

https://pass-through-tax-rules.vercel.app/api/mcp

Connect

Claude

Open Customize, then Connectors, and add a custom connector. Paste the endpoint and choose no sign-in. Open the Claude connector dialog with the name and URL filled in.

Cursor

In Cursor Settings, open Tools & MCP and add a custom server, or put this in ~/.cursor/mcp.json:

{
  "mcpServers": {
    "pass-through-tax-rules": {
      "url": "https://pass-through-tax-rules.vercel.app/api/mcp"
    }
  }
}

ChatGPT

On the web, open Plugins, choose the plus button, then Add custom MCP server. Paste the endpoint, leave authentication off, and confirm the warning before you create it.

Tools

ptet_rules

state, tax_year

Elective pass-through entity tax: who can elect, the deadline, the rate, credit or exclusion, estimates, and any sunset.
salt_cap

tax_year, filing_status, magi

Federal SALT cap for that year, with the phase-down, the floor, and the steps. The income figure is not stored.
bonus_conformity

state, tax_year

Whether the state conforms to IRC 168(k) and 179, the IRC conformity date, and the add-back or subtraction.
coverage

none

Loaded states and years, the last-verified date, and fields left unverified.

Covered states

10 states, tax years 2025 and 2026. Last full verification October 24, 2026. Texas and Florida are no-individual-income-tax entries. Changelog.

Example prompts

  1. Does Michigan have an elective pass-through entity tax for 2026? Who elects, what is the rate, and do owners get a credit or an exclusion?
  2. What is the 2026 federal SALT deduction cap for a single filer with MAGI of $555,000? Show the steps.
  3. Does California conform to IRC 168(k) bonus depreciation for tax year 2025?
  4. Which states and years are covered, and which fields are unverified?