Today's AI Tip
Make AI quote the document, then Ctrl+F every quote
A plausible answer with an extra detail
Real output · GPT-5.5 (OpenAI API) · Oct 2026
With a plain prompt (no quote rule, no “only the spec sheet”), the answer added “unless plugged in.” The spec sheet never says it runs while plugged in, and a customer could hold you to it.
A quote turns “trust me” into a check
Every answer ends with a word-for-word quote from the document. If the document doesn’t answer, the AI says “Not in the spec sheet” and gives no quote.
Source: Anthropic Claude docs, Reduce hallucinations, checked Oct 2026
The prompt to copy
Tested in GPT-5.5 (OpenAI API), Oct 2026
Paste your document and your questions underneath, each in its own tags: <spec_sheet> and <questions>. I tested it on a fictional projector spec sheet with 8 customer questions.
Now every answer shows its source
Real output · GPT-5.5 (OpenAI API) · Oct 2026
The “unless plugged in” line is gone in this one run. Each answer carries a quote, and the phone-charging question, which the sheet doesn’t answer, says “Not in the spec sheet.”
7 of 7 quotes were really there
I searched the sheet for each quote with exact text. All 7 were found word for word, and 1 question was marked “Not in the spec sheet.” That was one run on one short document.
A found quote isn’t a verdict
A found quote proves the words exist, not that the answer follows. Can a USB-C laptop connect? Yes, “if your USB-C port supports DisplayPort Alt Mode” (a USB-C video standard), which the sheet can’t confirm.
Try it: Add the quote rule to your next spec-sheet question, then Ctrl+F every quote it gives you.
Check twice before you forward
Check two things: is the quote there, and does it support the answer? Before uploading real documents, remove names, account numbers and other personal details, and check the tool’s data policy or your employer’s approved tools.
Sources and assumptions
- Reduce hallucinations - Claude Platform Docs (Anthropic): Recommends 'Verify with citations': have the model cite quotes and sources for each claim, and verify each claim by finding a supporting quote, retracting it if none is found. Recommends giving permission to say 'I don't know'. Frames word-for-word quote extraction first as a technique for long documents (>20k tokens), so this one-page test applies the principle rather than that exact technique. States that the techniques 'significantly reduce hallucinations' but 'don't eliminate them entirely'. (checked 2026-10-02)
Assumptions:
- The spec sheet, product name (Northwind Lumen P3) and the 8 customer questions are fictional sample material written for this test.
- Both tests ran once each on GPT-5.5 through the OpenAI API (default settings, no system message, no reasoning-effort override) on 2026-10-02 (UTC timestamp 2026-10-03). This is not the ChatGPT app and not Claude. A Claude Sonnet 5.5 run was attempted but failed to execute in the research environment, so it has no output and must not be shown or claimed. The post may only name GPT-5.5 (OpenAI API) as tested.
- The exact-text check was a fixed-string search (grep -F, the same as Ctrl+F) for each quoted sentence against the spec sheet. Leading list dashes are not part of the quotes. All 7 quotes matched exactly.
- The 'unless plugged in' line counts as unsupported because the spec sheet describes charging (65 W USB-C PD, about 2 hours to full) but never says the projector can run while plugged in.
- Result counts (7 of 7 quotes verbatim, 0 paraphrased, 0 missing, 1 'Not in the spec sheet') come from one run on a one-page document. They are not typical rates and must not be presented as such.
- Q3 ('Yes, if your USB-C port supports DisplayPort Alt Mode') and Q6 ('not listed as included') are counted as correct. They are the limitation example because the quote supports only part of the answer: the laptop's own port and the absence of a case can't be proven by a quote.
The short version
- Ask for a word-for-word quote after every answer.
- Tell it to say “Not in the spec sheet.”
- Ctrl+F each quote in the document.
- A found quote still needs a sense check.
