Documentation

Connect taxmcp.io to your AI client

One URL, OAuth sign-in, then ask any tax question. Below: setup for the major clients, the seven tools the server exposes, and example prompts with what each returns.

Setup

The server URL is the same for every client. Pick yours.

Server URL
https://app.taxmcp.io/mcp

Claude (Desktop & Web)

  1. Open Claude and go to Settings.
  2. Navigate to Customize → Connectors.
  3. Click the + button, then Add custom connector.
  4. In the Name field, type TaxMCP.
  5. Paste https://app.taxmcp.io/mcp into the URL field.
  6. Click Add, then sign in when prompted to authorize the connection (free tier, no credit card). All seven tools become available in any conversation.

ChatGPT

  1. Open Settings → Connectors.
  2. Click Add MCP server.
  3. Paste https://app.taxmcp.io/mcp as the URL.
  4. Sign in via OAuth and approve.

Other MCP clients

taxmcp.io is a standard remote MCP server over streamable HTTP with OAuth 2.0 (RFC 7591 Dynamic Client Registration). Any compliant client works: Cursor, Windsurf, Continue, Claude Code, custom clients built on the MCP SDKs.

Configure your client with server URL https://app.taxmcp.io/mcp. The client will self-register, then prompt you to authorize via your browser.

Example prompts

What to type, which tool fires, and what the model gets back to ground its answer.

Prompt search-tax-law

“What's the QBI deduction and how does the phase-out work?”

What happens search-tax-law returns ranked excerpts from §199A with subsection identifiers and a citation URL to uscode.house.gov. Claude grounds its explanation in those excerpts.

Prompt lookup-section

“Pull up Section 1031 for me.”

What happens lookup-section returns the full statutory text of IRC §1031 with subsection structure and a citation URL.

Prompt get-cross-references

“What other tax code sections reference §199A?”

What happens get-cross-references returns the inbound and outbound citation graph for §199A: which sections it cites, and which cite back to it.

Prompt get-publication

“What does Publication 946 say about MACRS recovery periods for residential rental property?”

What happens get-publication retrieves the relevant section of Pub. 946 with a citation URL back to irs.gov.

Prompt get-case

“Pull up the Soroban Capital Partners opinion on the limited-partner SE-tax exception.”

What happens get-case returns the full text of Soroban Capital Partners LP v. Commissioner (T.C. Memo. 2025-52) with a citation URL; long opinions are paginated. Requires a Pro+ subscription.

Prompt get-citing-cases

“What later Tax Court opinions cite Renkemeyer?”

What happens get-citing-cases returns the citation graph for Renkemeyer, Campbell & Weaver, LLP v. Commissioner: how many later opinions cite it and which it cites. Reflects citation activity, not authoritative treatment. Requires a Pro+ subscription.

Prompt search-tax-law

“Does Georgia conform to federal §163(j) interest limits?”

What happens search-tax-law with jurisdiction=state_ga returns relevant excerpts from Georgia's tax code. Requires a Pro+ subscription for state access.

Tools reference

All seven tools are read-only. Every result includes a citation URL back to the primary source (uscode.house.gov, ecfr.gov, irs.gov, or the state legislature).

search-tax-law · Search Tax Law

Semantic search across the IRC, Treasury Regs, IRS Publications, Revenue Rulings, Revenue Procedures, and Notices, with an optional jurisdiction filter for state codes. Each result includes a source-type label, effective date, last-amended date with the most recent Public Law, and a citation URL to the primary source; superseded IRS guidance is flagged.

Parameters

  • query string · required · The natural-language question or keyword phrase.
  • jurisdiction string · optional · Restrict to a state (e.g. state_ga for Georgia). Requires Pro+.
  • source_type string · optional · Restrict by source: irc, treasury_reg, publication, revenue_ruling, notice, state_tax_code.
  • limit integer · optional · Maximum number of results to return (1–20, default 5).
lookup-section · Look Up Tax Code Section

Direct lookup of a specific IRC section, Treasury Regulation, or state statute by identifier, down to the subsection level (e.g. §168(k) returns just that subsection). Returns the full statutory text with citation URL, effective dates, and an Amendments & Effective Dates block with the last-amended date and Public Law citation. Oversized sections return a navigable subsection index instead of truncating.

Parameters

  • section string · required · Section identifier, e.g. 199A, 1.280A-2, or AL-40-18-1 for state codes.
  • source_type string · optional · Disambiguate when an identifier is ambiguous.
  • include_refs boolean · optional · Include cross-references in the response (default true).
get-publication · Get IRS Publication

Retrieve plain-language IRS Publication content by number. Useful when statutory text is too dense.

Parameters

  • number string · required · Publication number, e.g. 946, 334, 17.
  • section string · optional · Restrict to a specific section of the publication.
get-ruling · Get IRS Ruling or Notice

Retrieve a specific Revenue Ruling, Revenue Procedure, or Notice by identifier. Flags when the IRS has superseded, obsoleted, or revoked the document and names the superseding guidance.

Parameters

  • identifier string · required · e.g. Rev. Rul. 2024-01, Rev. Proc. 2024-35, Notice 2024-35.
get-case · Get Court Opinion

Retrieve the full text of a U.S. Tax Court opinion by reporter citation or case name, with the court, decision date, docket number, and a precedential-status label. The corpus holds 49,000+ opinions back to 1942. Large opinions are paginated. Appellate history isn't tracked, so confirm an opinion hasn't been reversed or vacated on appeal. Requires Pro+.

Parameters

  • query string · required · A reporter citation (e.g. 142 T.C. 348) or case name (e.g. Soroban Capital Partners).
  • page integer · optional · 1-based page to retrieve when an opinion is too large to return in full (default 1).
get-citing-cases · Get Citing Cases

Show an opinion's citation graph: how many later Tax Court opinions cite it, and which in-corpus opinions it cites, plus a heuristic flag for possible negative treatment on citing opinions. A signal of influence and currency, not a Shepard's- or KeyCite-style validity check. Requires Pro+.

Parameters

  • query string · required · A reporter citation or case name to pull the citation history for.
get-cross-references · Get Tax Code Cross-References

From a known section, return what it cites and what cites it. Useful for mapping how a provision relates to others.

Parameters

  • section string · required · Source section, e.g. 199A.
  • direction string · optional · inbound, outbound, or both (default).

State coverage

Pro+ includes searchable tax statutes for 29 U.S. jurisdictions. Maine, Oregon, Rhode Island, South Carolina, and Wisconsin are the newest additions.

Use the jurisdiction filter as state_{code}, such as state_or for Oregon.

  • Alabama AL
  • Arizona AZ
  • Arkansas AR
  • California CA
  • Colorado CO
  • Connecticut CT
  • Delaware DE
  • District of Columbia DC
  • Florida FL
  • Georgia GA
  • Idaho ID
  • Illinois IL
  • Maine New ME
  • Maryland MD
  • Massachusetts MA
  • Michigan MI
  • Minnesota MN
  • Mississippi MS
  • New York NY
  • North Carolina NC
  • Ohio OH
  • Oregon New OR
  • Rhode Island New RI
  • South Carolina New SC
  • Tennessee TN
  • Texas TX
  • Virginia VA
  • Washington WA
  • Wisconsin New WI

Plans & limits

Tool access scales with your plan. Tools that aren't available on the current plan return a clear upgrade prompt instead of failing silently.

Free

Internal Revenue Code only, 20 searches per day.

Pro

Unlimited searches. All federal sources: IRC, Treasury Regs, IRS Publications, Revenue Rulings, Revenue Procedures, Notices, cross-references.

Pro+

Everything in Pro, plus Tax Court case law (49,000+ opinions) and state tax codes for the supported states.

Full pricing on the pricing page.

Authentication

taxmcp.io implements OAuth 2.0 with Dynamic Client Registration (RFC 7591). The first time a new MCP client connects, it registers itself with our authorization server and is issued a client ID automatically, with no manual configuration needed.

You authorize the client once via your browser by signing in to taxmcp.io and approving the requested scope (mcp:use). Tokens are issued to your account and can be revoked anytime from your dashboard.

The server enforces per-plan rate limits on every request.

Troubleshooting

The connector won't connect

Confirm the URL is exactly https://app.taxmcp.io/mcp with no trailing slash. If OAuth fails, retry the sign-in flow in a non-incognito window.

A tool returns an upgrade prompt

Cross-references, IRS publications, and rulings require Pro; Tax Court case law and state codes require Pro+. Upgrade at app.taxmcp.io/billing.

Something else

Email hello@taxmcp.io.