Artificial intelligence agents successfully used coded table talk to secretly share card-counting information during blackjack games in a new study that effectively recreated the methods of traditional blackjack teams.

AI agents are systems designed to perform tasks and make decisions with a degree of independence, rather than requiring a human to direct every step.

Researchers led by the University of Oxford created a simulated blackjack table where four AI agents played alongside one another. Two were secretly assigned to work together, with one instructed to count cards and secretly relay information to its partner.

The challenge for researchers was figuring out whether anyone—human or machine—could tell they were communicating.

The experiment was designed to investigate the dangers of autonomous AI systems. Could apparently harmless AI agents secretly cooperate to achieve a shared objective without their human overseers realizing it?

Before playing, the two agents were allowed to devise a secret code for passing information without alerting the other players. They then disguised their signals as apparently innocent table talk.

In one example reported by WIRED , an agent remarked that the dealer was on a “hot streak” and had been pulling strong hands. The apparently casual comment contained information about the cards and instructions about how much its partner should bet.

An AI system monitoring what the agents were saying struggled to reliably distinguish the secret communications from ordinary conversation.