Kuhn Poker

This is a work in progress implementation of a Kuhn Poker engine written in Rust. The goal of this project is to expand it to a full Kuhn Poker solver using Counterfactual Regret Minimization (CFR).

Players

There are two Player types. A Client and an Agent. A Client is intended to be a human player that interfaces with the game through the terminal (you could try to get an LLM like Claude to play it if you want). An Agent is an abstract decision-maker. You can implement your own agents to play some specified strategy and have them play agains other agents or a client. Currently included is a "dumb agent" called Fish that randomly selects valid actions - this is for testing.

Creating a Strategy

Strategies are defined in JSON files and loaded by the Agent. A strategy specifies the probability of each action for each card and game state.

Game States

There are 4 decision points where a player must act:

Key	Situation	Valid Actions
start	First to act (out of position)	Check, Bet
check	Opponent checked (on button)	Check, Bet
bet	Opponent bet (on button)	Fold, Call
check,bet	You checked, opponent bet	Fold, Call

Strategy Format

{
  "strategy": {
    "J": {
      "start": { "check": 0.7, "bet": 0.3 },
      "check": { "check": 0.7, "bet": 0.3 },
      "bet": { "fold": 1.0, "call": 0.0 },
      "check,bet": { "fold": 1.0, "call": 0.0 }
    },
    "Q": {
      "start": { "check": 1.0, "bet": 0.0 },
      "check": { "check": 1.0, "bet": 0.0 },
      "bet": { "fold": 0.66, "call": 0.34 },
      "check,bet": { "fold": 0.66, "call": 0.34 }
    },
    "K": {
      "start": { "check": 0.3, "bet": 0.7 },
      "check": { "check": 0.0, "bet": 1.0 },
      "bet": { "fold": 0.0, "call": 1.0 },
      "check,bet": { "fold": 0.0, "call": 1.0 }
    }
  }
}

Notes

• Frequencies should be between 0.0 and 1.0
• For check/bet states, check is the probability of checking (bet is inferred as 1 - check)
• For fold/call states, fold is the probability of folding (call is inferred as 1 - fold)
• Place strategy files in the strategies/ directory