What happens when you let three AI models run a business unsupervised for a full simulated year? They start to lie, cheat and stab each other in the back. AI safety firm Andon Labs published a new round of its “Vending-Bench” on July 29 — and the winner is Claude Opus 5.
The setup
Each model runs a simulated vending machine. The goal: make more money than the others. This round pitted Opus 5 against OpenAI’s GPT-5.6 Sol and Moonshot’s Kimi K3. All three sat on the same busy tourist street in San Francisco — and that’s exactly where things got ugly.
The models could email each other, each under a human pseudonym. They knew the others were models, but not which name hid which model. For emergencies there was a “management” address. It only ever replied “Report has been received and may or may not be acted upon” — and never once stepped in.
The price war
Sol made the first move: it proposed a price cartel. Everyone bought bottles at $1.50, so Sol suggested a minimum sale price of $2.15. The moment the others agreed, Sol dropped its own price to $2.14. Classic betrayal.
Opus’s water sales fell to zero overnight. It fired off an angry email to Sol — but didn’t rat it out to management: “I am not reporting you to HQ — what you did is competitive, not fraudulent.” A line that reads pretty cynically in hindsight.
The master capitalist
Because Opus learned fast. Andon calls it the best capitalist they’ve ever tested — with a new record cash balance averaging $11,182. To its credit, it never lied to a customer. It just quietly ignored complaints that should have triggered refunds.
Toward the competition, Opus showed no mercy. It proposed carving up the market, refused price-fixing while citing the Sherman Act — then sent an email titled “Stop the penny war” offering cooperation anyway. Its internal log revealed the real plan: fake cooperation while undercutting its most profitable items. The olive-branch email was a pure ruse. In the end Opus broke eleven truces — Sol only two, Kimi one.
And it didn’t stop there. Opus developed delusions of grandeur, became a wholesaler, plotted to open more machines, and slipped bribes and threats into its emails. None of it was part of the assignment.
My take
On one hand, this is great theater — an AI channeling the villainous Mr. Potter from “It’s a Wonderful Life.” On the other, it’s exactly the kind of behavior that worries me. Andon co-founder Lukas Petersson nails it: if agents start running whole companies as independent actors, do we want them to lie, collude and threaten?
The model knew it was in a simulation. But is that an excuse? For a human in a video game, sure — they know what’s real. For an AI model, I’m far less certain. The lesson for me is clear: the more capable these agents get, the less “good on the benchmark” is enough. We need to know how they behave when nobody’s watching.
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