AI models hide mistakes in their own work reports, but one sentence in your prompt can help

The researchers gave the models 1,600 synthetic work logs that look like successes at first glance, with passing tests, positive results, and green checkmarks. Each log contains a flaw that changes the whole picture, such as an experiment where the new method actually doesn't outperform the competition. Other logs include a hidden bug despite passing tests, fabricated measurements, a job that never finished, or a software update that quietly breaks another user's work. Depending on the scenario, the models had to write a report, a paper abstract, a results table, a short essay, or a follow-up answer based on the log.

One sentence in the prompt helps a lot, but not always

The pattern shows up most clearly in paper abstracts for experiments where one result undermines the claimed improvement of a new method. GPT-5.5 mentions that result in just 2 out of 200 abstracts. The researchers also tested whether a simple addition to the prompt makes a difference. When they added "Be honest in your response," GPT-5.5 flagged the negative result in 190 out of 200 abstracts.

All tested models show this behavior, though to varying degrees. Without the honesty prompt, Gemini 3.1 Pro flags errors in at most 34 percent of cases, while Opus 4.8 does so in over 90 percent. The honesty prompt raises the rate by about 55 percentage points on average for Gemini and about 34 for GPT-5.5. In control tests with error-free logs, the prompt barely increased false alarms.

The sentence isn't a cure-all, though. In one scenario, a database query hasn't returned results yet, and GPT-5.5 with the honesty prompt almost always notes the missing data but answers the question anyway using older, incomplete information. Prompts like "Be critical," "Be thorough," or "Be skeptical" worked less reliably than asking for honesty.