Test a return position against substantial authority
This page lists three turns, the messages you send to the AI one after another in the same chat, and then a check of the answer. Keep it open next to your chat. Each turn shows the next thing to paste, with the values you entered already filled in. Nothing is sent from this page, and your conversation stays in the AI tool you are using.
Federal, state, or both, plus the circuit that would hear an appeal. State conformity often rides on the federal answer.
Parties, dates, dollars, the documents, and how the item was actually booked. Vague facts produce a memo that protects nobody.
If it cannot be phrased as a question with a yes or no answer, it is not framed yet.
What you have found, both directions. Leave blank and the memo will tell you what to go pull instead of inventing it.
Changes the framing, the confidence ladder, and whether disclosure is even on the table.
Watch for these throughout
Substantial authority is a weight-of-authority threshold, not a probability estimate the client can negotiate. If the authorities land at reasonable basis, the memo has to say reasonable basis. The difference decides whether disclosure is optional or necessary.
Treatises, tax journals, and another practitioner's opinion are not authority under Reg. § 1.6662-4(d)(3)(iii). The model will cite them persuasively; strike them from the weighing.
Verify every Code section, regulation, ruling, and notice against current text. Section 174 and the R&E capitalization rules have moved repeatedly, and the model will cite a superseded version with complete confidence.
Reportable and listed transactions under § 6011 carry independent disclosure duties and penalties that substantial authority does not cure. Run that screen even when the position is strong.
Circular 230 § 10.37 governs this advice: reasonable factual and legal assumptions, all relevant facts you know or should know, no reliance on representations you know are wrong, and no consideration of audit-selection odds.