game-ai-client 0.1.4

Client + MCTS helpers for board game AI integration.

Game AI Client SDK

A Python SDK for integrating AI into turn-based board games using Monte Carlo Tree Search (MCTS). This framework provides a generic interface that allows game developers to add AI opponents to their games with minimal coupling to game-specific logic.

Features

• Generic Game Interface: Implement any turn-based game with a simple protocol
• MCTS AI Engine: Powerful AI using Monte Carlo Tree Search with customizable strategies
• Design Patterns: Built with Strategy and State patterns for extensibility
• Event Logging: Built-in match and move logging via RabbitMQ
• Minimal Integration: Keep full control of your game logic

Installation

pip install game-ai-client==0.1.2

Quick Start

Import the SDK:

from game_sdk import AIGameClient
from game_sdk.utils import build_generic_state

RabbitMQ Setup (Optional)

The SDK includes built-in event logging to RabbitMQ. To enable it, start RabbitMQ using Docker:

docker-compose up -d

This will start RabbitMQ on:

• AMQP port: 6000
• Management UI: http://localhost:15672

Configure via environment variables:

export RABBITMQ_HOST=localhost
export RABBITMQ_PORT=6000
export RABBITMQ_USER=guest
export RABBITMQ_PASS=guest

If RabbitMQ is unavailable, the SDK gracefully falls back to stdout logging.

Integration Guide

You keep full control over your game logic. To use the framework, you only need to provide:

1. Players list
2. Legal moves function
3. Apply-move function for AI state transitions

• Players list:

players = [
    {"id": "P1", "type": "human",  "symbol": "X"},
    {"id": "P2", "type": "ai_mcts","symbol": "O"},
]

• Legal moves function Return all legal moves for the current player, as a list of dicts:

def compute_legal_moves(board, players, current_player_symbol):
    player_index = next(i for i, p in enumerate(players)
                        if p["symbol"] == current_player_symbol)
    moves = []
    for r in range(len(board)):
        for c in range(len(board[0])):
            if board[r][c].strip() == "":
                moves.append({
                    "id": f"PLACE_{r}_{c}",         # string id is recommended
                    "player_index": player_index,   # index in players[]
                    "type": "PLACE_MARK",
                    "position": {"row": r, "col": c},
                })
    return moves

Apply-Move Function

This is the only function needed from your game to enable AI. It takes a generic state and move, returns a new state:

from typing import Dict, Any, List
from game_sdk.utils import build_generic_state

State = Dict[str, Any]
Move = Dict[str, Any]

def apply_move_my_game(state: State, move: Move) -> State:
    players: List[Dict[str, Any]] = state["players"]

    # --- decode board from generic state ---
    board_info = state["board"]
    int_board = board_info["cells"]              # 2D ints
    symbol_map = {0: " "}
    for idx, p in enumerate(players):
        symbol_map[idx + 1] = p["symbol"]

    board = [[symbol_map[v] for v in row] for row in int_board]

    # --- apply the move ---
    r = move["position"]["row"]
    c = move["position"]["col"]
    player_index = move["player_index"]
    symbol = players[player_index]["symbol"]
    board[r][c] = symbol

    # --- next player ---
    next_player_index = (player_index + 1) % len(players)
    next_symbol = players[next_player_index]["symbol"]

    # --- terminal & result: YOUR logic here ---
    # is_terminal_and_winner() should be implemented by you and return:
    #   (finished: bool, winner_symbol: Optional[str])
    finished, winner_symbol = is_terminal_and_winner(board)

    result_map = None
    if finished:
        # winner_to_results() should return (result_str, result_map)
        # e.g. result_map = {"P1": 1.0, "P2": -1.0}
        _, result_map = winner_to_results(winner_symbol, players)

    move_count = state["extra"].get("move_count", 0) + 1
    legal_moves = [] if finished else compute_legal_moves(board, players, next_symbol)

    # --- build and return the new state ---
    return build_generic_state(
        game_id=state["game_id"],
        board=board,
        players=players,
        current_player_symbol=next_symbol,
        move_count=move_count,
        finished=finished,
        legal_moves=legal_moves,
        result=result_map,
    )

Building a state for the AI / logging

On each turn, describe the current position using build_generic_state:

state = build_generic_state(
    game_id="my_game_id",
    board=board,                        # 2D list of symbols, e.g. [["X"," ","O"], ...]
    players=players,
    current_player_symbol=current_sym,  # whose turn it is
    move_count=move_count,
    finished=False,                     # or True if you know it’s over
    legal_moves=compute_legal_moves(board, players, current_sym),
    result=None,                        # for terminal state: {player_id: score}
)

Using AIGameClient in your loop

Create client and start match:

client = AIGameClient(
    game_id="my_game_id",
    api_key="demo-key",
    apply_move_fn=apply_move_my_game,
)

match_id = client.start_match(players=players, metadata={"mode": "casual"})

Each turn:

while not finished:
    current_sym = ...                 # your turn logic
    legal_moves = compute_legal_moves(board, players, current_sym)

    state = build_generic_state(
        game_id="my_game_id",
        board=board,
        players=players,
        current_player_symbol=current_sym,
        move_count=move_count,
        finished=False,
        legal_moves=legal_moves,
    )

    current_player = next(p for p in players if p["symbol"] == current_sym)

    if current_player["type"] == "ai_mcts":
        # ---- AI turn ----
        client.send_state(match_id, state)
        move = client.best_move(match_id, iterations=800)
    else:
        # ---- human turn ----
        move = get_human_move_somehow(legal_moves)

    # Apply move in your game
    apply_move_on_real_board(board, move, current_sym)
    
    # log the move 
    client.log_move(match_id=match_id, state=state, move=move)

    # Update finished / winner using your own logic
    finished, winner_symbol = is_terminal_and_winner(board)
    move_count += 1

End the match:

result_str, result_map = winner_to_results(winner_symbol, players)

final_state = build_generic_state(
    game_id="my_game_id",
    board=board,
    players=players,
    current_player_symbol=current_sym,
    move_count=move_count,
    finished=True,
    legal_moves=[],
    result=result_map,
)

client.end_match(
    match_id=match_id,
    result=result_str,
    final_state=final_state,
)

Architecture

Design Patterns

The SDK implements multiple design patterns for extensibility and maintainability:

Strategy Pattern (MCTS Customization)

The MCTS algorithm is decomposed into four pluggable strategies:

from game_sdk.mcts import (
    MCTSStrategy,
    DefaultSelectionStrategy,
    DefaultExpansionStrategy,
    DefaultSimulationStrategy,
    DefaultBackpropagationStrategy,
)

# Use custom strategies
custom_mcts = MCTSStrategy(
    selection_strategy=DefaultSelectionStrategy(),
    expansion_strategy=DefaultExpansionStrategy(),
    simulation_strategy=DefaultSimulationStrategy(),
    backpropagation_strategy=DefaultBackpropagationStrategy(),
)

Each strategy can be independently customized:

• SelectionStrategy: How to traverse the tree (default: UCB1)
• ExpansionStrategy: How to add nodes (default: single unexpanded move)
• SimulationStrategy: How to simulate games (default: random rollout)
• BackpropagationStrategy: How to update values (default: visit counts + rewards)

State Pattern (MCTS Phases)

MCTS iterations follow a state machine:

• Selection Phase → Expansion Phase → Simulation Phase → Backpropagation Phase → Complete

Each phase handles its work and transitions to the next state, providing clean separation of concerns.

Protocol-Based Design

The SDK uses Python protocols for game integration. Implement the TurnBasedGame protocol for compile-time type checking:

from game_sdk.ai_client import TurnBasedGame, Move
from typing import List

class MyGame(TurnBasedGame):
    def get_legal_actions(self) -> List[Move]:
        # Return all legal moves
        pass

    def is_game_over(self) -> bool:
        # Check if game is finished
        pass

    def game_result(self) -> int:
        # Return result: 1 (win), -1 (loss), 0 (draw) from current player perspective
        pass

    def move(self, action: Move) -> "MyGame":
        # Apply move and return new game state
        pass

Component Overview

┌─────────────────────────────────────────────┐
│   Game Implementation                       │
│   - Your game logic                         │
│   - TurnBasedGame protocol                  │
└─────────────────────────────────────────────┘
                    ↓
┌─────────────────────────────────────────────┐
│   AIGameClient                              │
│   - State management                        │
│   - MCTS integration                        │
└─────────────────────────────────────────────┘
                    ↓
┌─────────────────────────────────────────────┐
│   MCTS Engine (Strategy Pattern)            │
│   - Selection → Expansion                   │
│   - Simulation → Backpropagation            │
└─────────────────────────────────────────────┘
                    ↓
┌─────────────────────────────────────────────┐
│   Event Logging (RabbitMQ)                  │
│   - Match lifecycle events                  │
│   - Move logging                            │
└─────────────────────────────────────────────┘

Advanced Usage

Customizing MCTS Parameters

Control the AI strength and behavior:

# More iterations = stronger AI (but slower)
move = client.best_move(match_id, iterations=1000)

# Fewer iterations = faster but weaker AI
move = client.best_move(match_id, iterations=100)

Generic State Format

The SDK uses a standardized state representation:

{
  "game_id": "tictactoe",
  "state_id": "unique-uuid",
  "turn_index": 5,
  "players": [
    {"id": "P1", "type": "human", "symbol": "X"},
    {"id": "P2", "type": "ai_mcts", "symbol": "O"}
  ],
  "board": {
    "representation": "grid",
    "rows": 3,
    "cols": 3,
    "cells": [[1, 0, 2], [0, 1, 0], [2, 0, 0]],
    "legend": {
      "0": "empty",
      "1": "player_1_piece",
      "2": "player_2_piece"
    }
  },
  "status": "IN_PROGRESS",
  "is_terminal": false,
  "legal_moves": [...],
  "result": null,
  "extra": {"move_count": 5}
}

Example Implementation

See tictactoe.py for a complete working example demonstrating:

• TurnBasedGame protocol implementation
• Human vs AI gameplay
• State management
• Event logging

Requirements

• Python 3.9+
• pika 1.3.2 (for RabbitMQ)

Credits

Tic-Tac-Toe example adapted from: https://gist.github.com/qianguigui1104/edb3b11b33c78e5894aad7908c773353