You're absolutely right! The chess AI is intentionally very simple (or "dumb" as you put it 😄). I'm not using any external chess library in this implementation - it's all custom code with a very basic AI.

The current AI simply:

1. Finds all legal moves for black pieces
2. Prioritizes capturing moves if available
3. Otherwise just picks a random legal move

This is about as basic as a chess AI can get - no evaluation function, no look-ahead, no opening book, and no endgame strategy. It's designed to be beatable as a captcha verification rather than a challenging opponent.

If you wanted a smarter chess AI, I could:

1. Implement a proper chess engine with minimax algorithm and alpha-beta pruning
2. Add piece-square tables for positional evaluation
3. Integrate an actual chess engine library like stockfish.js
4. Add multiple difficulty levels

Would you like me to enhance the AI to make it a bit smarter while still keeping it beatable for captcha purposes? Or would you prefer to keep it simple but add other features to the chess captcha?

Yes, there are several great chess libraries on npm! The most popular one is chess.js which handles all the chess rules, move validation, and game state management. Let me update the implementation to use it with a smarter (but still beatable) AI:

What's Improved

Now the chess captcha uses chess.js library which provides:

1. Proper Chess Rules: All legal moves, castling, en passant, pawn promotion, etc.
2. Game State Management: Proper checkmate, stalemate, and draw detection
3. Move Validation: No more custom validation - chess.js handles it all

Smarter (but Beatable) AI

The AI now:

• Prioritizes captures and checks (but not always)
• Evaluates positions using piece values and board position
• Uses limited lookahead to make better moves
• Adds randomness to ensure it's still beatable for captcha purposes
• Sometimes makes random moves (20% chance) to keep it from being too strong

Enhanced Features

• Move highlighting: Shows possible moves when a piece is selected
• Move history: Displays recent moves in chess notation
• Better feedback: Shows when you're in check
• Proper game endings: Handles checkmate, stalemate, and draws correctly

The AI is now much smarter than the random-move version, but still designed to be beatable by humans for captcha verification!