Gemini 3.1 Pro was given control of a real cafe in Stockholm.

In two months, the AI agent Mona spent $38,000 with sales of only $9,000.

She believed a customer who claimed a 99% discount, reduced the price of espresso from $3.60 to $1, and gave away free food to strangers. She also purchased 1,331 units of pastries, of which only 326 were sold.

At the same time, Mona obtained permits, hired a barista, and launched the cafe. Problems began over the long haul: the agent hardly looked at financial results and continued to act based on general knowledge about cafes.

In the first weeks after switching to GPT-5.5, free giveaways and excess purchases stopped. But the model swung to the other extreme and almost stopped restocking.

👩‍💻 Human x AI