Tax MCP Server
Give Claude, ChatGPT, or any MCP-compatible client structured access to the Internal Revenue Code, Treasury Regulations, IRS Publications, Revenue Rulings, and Notices. Hosted. Versioned. Cited.
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.
Tools
Five read-only tools, each returning structured results with section identifiers and source URLs the model can cite.
search-tax-law Semantic search across the IRC, Treasury Regs, IRS Pubs, and Rulings. 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 or Notice (e.g. Rev. Rul. 2024-01).
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, 24+ IRS Publications, IRS Notices from 2003–present, and Revenue Rulings from 2019–present. 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.
Claude Desktop and ChatGPT have first-class MCP support and are the most common clients. taxmcp.io also works with any other MCP-compatible client: Cursor, Continue, custom clients built with the official SDKs, and anything else that speaks the protocol.
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, and Notices).
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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