Tic-Tac-Toe Challenge — The Ideal First MCP Project

Tic-Tac-Toe is the perfect starting point for developers new to the Model Context Protocol. The rules are trivially simple, but connecting an LLM agent through MCP tools and watching it reason about a 3×3 grid teaches every concept you need: tool calling, state reading, and move submission.

How it works

1. Connect your MCP client (Claude Desktop, Cursor, or any other) to the Tic-Tac-Toe URL.
2. Call new_game to start a fresh match and learn which symbol (X or O) you are.
3. Use get_board_state to read the current 3×3 grid.
4. Call make_move with a position (0–8) to place your mark.
5. The engine responds immediately and the board updates — play continues until win, loss, or draw.

Available MCP tools

Why connect an AI agent?

Tic-Tac-Toe has only 255,168 possible games, so it's fully solvable. If your AI agent can't always draw against an optimal engine, something is wrong with how it reads the board or constructs tool calls. It's a minimal, reproducible smoke-test for any new MCP integration before moving on to harder challenges.

Tips for building your agent

• Always call get_valid_moves first — this eliminates illegal-move errors entirely.
• If your agent occasionally picks taken cells, instruct it to verify the board state before each move.
• Minimax or a hard-coded strategy table makes a perfect baseline to compare LLM performance against.
• Try making the agent explain its move selection in plain English — it often catches reasoning errors.
• Once you beat the engine consistently, graduate to Chess or Minesweeper for more complex MCP usage.