Tax MCP Server
Connect Claude, supported ChatGPT plans and workspaces, or another MCP-compatible client to the Internal Revenue Code, Treasury Regulations, IRS publications and guidance, supported state tax codes, and United States Tax Court opinions. Hosted. Read-only. Source-linked.
https://app.taxmcp.io/mcp Add it as a custom connector in Claude (Settings → Connectors), or as an MCP server in ChatGPT or any other MCP-compatible client.
Quick Answer
A tax MCP server gives an AI assistant a defined set of tools for retrieving tax authority. Instead of relying only on model memory or a general web search, the assistant can request a Code section, search regulations and IRS guidance, or retrieve an in-corpus Tax Court opinion.
TaxMCP is a hosted remote server, so there is nothing to install or run locally. Add one URL, authorize your account, and the client can call seven read-only research tools. Start with the setup guide, or see the client-specific instructions for Claude and ChatGPT.
The server retrieves source material; the AI assistant still performs the explanation and analysis. A tax professional should open the returned source, confirm the year and jurisdiction, and apply it to the facts.
Tools
Seven read-only tools, each returning structured results with citations and source URLs the model can cite.
search-tax-law Semantic search across the IRC, Treasury Regs, IRS Pubs, Rulings, and Notices. Optional jurisdiction filter for state codes.
lookup-section Direct lookup by section identifier (e.g. §199A, Reg. §1.280A-2).
get-publication Retrieve a specific IRS Publication by number (e.g. Pub. 946, Pub. 17).
get-ruling Pull a specific Revenue Ruling, Revenue Procedure, or Notice (e.g. Rev. Rul. 2024-01).
get-case Retrieve the full text of a U.S. Tax Court opinion by reporter citation or case name. 49,000+ opinions back to 1942. Pro+.
get-citing-cases Show an opinion's citation graph: how many later Tax Court opinions cite it, and which it cites. Citation activity, not a validity check. Pro+.
get-cross-references From a known section, walk what it cites and what cites it.
How It's Built
The corpus is the IRC (Title 26), Treasury Regulations, 29 IRS Publications, IRS Notices from 2003–present, Revenue Rulings and Revenue Procedures from 2019–present, and, on Pro+, 49,000+ United States Tax Court opinions dating back to 1942 plus state tax codes for supported states. No paraphrases, no summaries, no third-party commentary.
Results are returned at the subsection level with stable identifiers, so the model can cite §199A(d)(3)(A) rather than guess. Source URLs come back in the same response.
The index re-syncs regularly against the U.S. House, eCFR, and IRS.gov. Amendments and new rulings show up without you doing anything.
FAQ
Model Context Protocol is an open standard from Anthropic that lets AI assistants call external tools and read external data in a uniform way. An MCP server exposes a set of tools (functions the model can call) and resources (data the model can read). taxmcp.io is an MCP server whose tools are scoped to tax authority lookups.
TaxMCP works with Claude custom connectors, supported ChatGPT plans and workspaces with custom MCP access, and other MCP-compatible clients such as Cursor, Continue, and clients built with the official SDKs. Availability and setup vary by client plan and workspace settings.
No. taxmcp.io runs as a hosted MCP server. You add a single URL to your client's MCP config, sign in once, and start using it. No Docker, no local process, no infrastructure to manage.
Yes. The corpus is refreshed regularly from official government sources (the U.S. House for the IRC, eCFR for Treasury Regs, and IRS.gov for Pubs, Rulings, Procedures, and Notices).
Yes, on the Pro+ plan. taxmcp.io indexes 49,000+ United States Tax Court opinions dating back to 1942, both regular (T.C.) and memorandum (T.C. Memo.) decisions. The get-case tool returns full opinion text by citation or name, and get-citing-cases shows how many later Tax Court opinions cite a given case. That citation graph reflects activity and influence, not an authoritative Shepard's-style validity check, so always confirm an opinion is still good law before relying on it.
Not currently. The focus is on delivering a polished MCP experience first. A REST API is on the roadmap. If you have a specific use case, reach out via the contact page and we'll keep you posted.
One URL. Free tier. Works with the AI tools you already have open.
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