Adding 'Do not guess' cut AI made-up fields from 70.7% to 20.2%
Calling the AI bluff: Adding "Do not guess" cut made-up fields from 71% to 20%
A benchmark tested 16 AI models and 3 paid APIs on web extraction, asking for fields that were sometimes absent. With the instruction 'Use null for any field whose value is not on the page. Do not guess.', models fabricated 20.2% of missing fields versus 70.7% without it. Firecrawl invented 24 of 36 missing fields, more than 13 of 16 models with the sentence. A cheap checker like GPT-6 Luna caught 38 of 49 made-up values for $0.0049.
All 16 models made up more without the sentence: 405 of 573 missing fields without it (70.7%), 116 of 574 with it (20.2%).
- datsci_est_2015
Cool, this will be added to harnesses and then it’ll stop being effective and we’ll move on to the next magical incantation.
- literalAardvark
I've used "you're not trained on this data, return exclusively grounded results" to good effect.
- Shacharp
The "do not guess" sentence works but the last 20% will only close when a system stops being told to avoid guessing and actually knows what it does not know.
A command can get you most of the way. It takes something else for the rest.