The Opponent

You take a seat opposite one counterparty for a whole session. Nothing is pre-written: every payoff is drawn when the round is dealt, and their move is computed by an agent that is modelling you. It opens shallow — someone who takes the payoffs at face value and is there to be exploited. But their reasoning depth climbs every time you beat them, so the guess that won the last round loses the next one, the pattern you fell into at matching pennies gets read back to you with the probability they assigned it, and the field you shaded against starts shading too. Twenty hands of prisoner's dilemma play out for real. A common-value auction reveals the truth after you have bid. Playing the textbook answer every round keeps you alive and gives up most of the edge.

💰

BankrollReal chips. Every round settles against it at whatever the arithmetic says. Zero → you are out.

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EdgeYour payoff versus what the textbook equilibrium move earns in the same draw. 50 is break-even.

🧠

ReadHow close you came to best-responding to their actual reasoning depth. Zero → you are the one being played.

🎯

ExposureHow far past the safe play you committed, decayed each round. Past 100% one bad call costs you.

Nothing here is scripted. They are running a model of you, and it updates.