Connect taxmcp.io once, then research in the ChatGPT conversations you already use. It returns source-linked results from the IRC, Treasury Regs, IRS Publications, Revenue Rulings, state tax codes, and U.S. Tax Court opinions.
The Difference
QBI deduction rules for SSTBs?
SSTBs are phased out above the threshold amounts under §199A(d)(4)(C)...
§199A(d)(4)(C) doesn't exist. §199A(d) only has paragraphs (1)–(3). Plausible-sounding subsection, fabricated.
QBI deduction rules for SSTBs?
A specified service trade or business is defined in §199A(d)(2). For SSTBs above the threshold, the phase-in and full disallowance mechanics live in §199A(d)(3), with the threshold amount itself defined in §199A(e)(2).
Setup
Create a free taxmcp.io account. You'll get a personal MCP connection URL.
In ChatGPT, add the connection URL as an MCP server. Save and reload.
Ask a tax question and open the returned source before relying on the answer.
FAQ
No. ChatGPT decides per question. Tax-flavored prompts route through taxmcp.io's tools; unrelated chats ignore the connector entirely. There's no slowdown or token cost on the conversations that don't need it.
It's an MCP server, which is the current standard for giving ChatGPT structured access to outside tools and data. Unlike a custom GPT, you don't have to start a new conversation in a particular workspace. taxmcp.io is available in any chat once it's connected.
It can still make mistakes in explanation or analysis. For tax questions routed through taxmcp.io, the section numbers, regulation text, and ruling references come from indexed primary sources rather than the model's memory, so you can open and verify them.
MCP / connector support is rolling out by plan and region. If you don't see it in your ChatGPT settings yet, the same taxmcp.io server works in Claude (Desktop and Web), Cursor, and any other MCP-compatible client today.
Free to start. Connect once, then research with source-linked results in ChatGPT.
Get Started Free