23NPCs Pokerbot

23NPC is a poker-playing bot originally developed for the Build4Good 2025 Pokerbot Challenge, a hackathon competition inspired by the MIT Pokerbots framework. The challenge involved building a bot that could compete in a modified version of Texas Hold'em called B4G Hold'em.

This repository includes our bot's implementation, which uses Monte Carlo simulations to estimate hand strength and makes decisions based on calculated equity and pot odds.

Bot Strategy: Monte Carlo + Smart Betting

The 23NPCs bot estimates its chance of winning using a Monte Carlo simulation of random opponent hands and board outcomes. Based on the estimated equity, the bot makes betting decisions using logic inspired by real-world professional strategies.

Key Logic

• Preflop:

  • If estimated equity > 60%, raise aggressively (≈2.5× big blind).
  • If marginal, call small bets or fold to larger ones.

• Postflop:

  • Raise if equity exceeds pot odds by at least 20%.
  • Raise sizing: ~67% of the current pot.
  • Call if equity ≥ pot odds; otherwise, fold.

The core equity calculation is handled by a custom monte_carlo_equity function, simulating hundreds of hands per decision for accurate win-rate estimates.

B4G Hold'em Rules Summary

• Each player is dealt 3 private (hole) cards.
• The community board reveals:
  • 2 cards (flop), followed by a betting round.
  • 2 additional cards, then a final betting round.
• Hand rankings follow Texas Hold'em standards.
• Only two rounds of betting per hand.

Match Format

• Matches are played over 5,000 hands between two bots.
• Each hand:
  • Players start with 500 chips.
  • Small blind: 5 chips
    Big blind: 10 chips
  • Blinds alternate each hand.
  • Chips reset each hand; cumulative bankroll determines the winner.

Time Constraints

• Each bot has a 180-second time budget per match.
• Once time runs out, the bot will auto-fold all remaining hands.

Project Structure

• engine.py – Main engine for running matches (do not edit).
• config.py – Match configuration (editable).
• bots/23NPCs/ – Contains the 23NPCs bot implementation.
  • Based on a required skeleton/ structure.
• player_chatbot/ – Command-line interface for testing bots interactively.

Dependencies

• Python ≥ 3.5
• eval7 – For poker hand evaluation

  pip install eval7