A unique twist on classic Tic Tac Toe with a learning AI and limited marks per player.

Play the game here

• Each player can only have 3 marks on the board
• Placing a 4th mark removes your oldest mark
• Connect 3 in a row to win
• Pulsing marks show which one will disappear next

• Google Gemini 2.0 Flash Lite AI: Real AI opponent powered by Google's latest Gemini 2.0 Flash Lite model
• Intelligent Gameplay: AI understands the unique ShiftTac rules and fading mechanics
• Fallback AI: Works without API key using basic strategic AI
• Environment Variable Support: Secure API key management via Vercel environment variables
• Score tracking: Keeps track of your wins and losses
• Human vs Human mode: Play against a friend
• Minimalist design: Clean black and white interface
• Real-time AI thinking panel: See how the AI analyzes moves and makes decisions

1. Click any cell to place your X
2. Each player gets only 3 marks at a time
3. Win by connecting 3 marks in a row

• Top-right toggle: Switch between AI and Human opponent
• Bottom center: Click restart icon after a game ends
• Bottom right: View and reset scores (hold to reset)
• Bottom left: Game info and rules

1. Fork this repository to your GitHub account
2. Go to vercel.com/new and import your fork
3. Add environment variable GEMINI_API_KEY with your API key
4. Deploy! See VERCEL_DEPLOYMENT.md for detailed instructions

1. Clone or download this repository
2. Open index.html in any modern browser
3. Enter your Gemini API key when prompted, or skip to use basic AI

# Install dependencies
npm install

# For local development with environment variables
npm run build
npx http-server dist -p 3000

# For simple development
npm run dev

1. Visit Google AI Studio
2. Sign in with your Google account
3. Create a new API key
4. For Vercel deployment: Add as GEMINI_API_KEY environment variable
5. For local play: Enter when prompted in the game

Note: API keys are stored securely via Vercel environment variables (encrypted at rest) or locally in your browser. Keys are never sent anywhere except to Google's official Gemini API.

• Frontend: Vanilla HTML, CSS, and JavaScript
• AI Integration: Google Gemini 2.0 Flash Lite API via direct fetch calls
• Dependencies: Zero external dependencies - pure vanilla JS
• Storage: localStorage for game state, scores, and API key
• Deployment: Vercel-ready with environment variable support
• Build System: Custom build script for secure API key injection