Chess Powers
Real-time multiplayer chess with AI-generated custom piece rules
# what it is
A multiplayer chess variant platform where players define custom piece behaviour in plain English. A GPT-4o agent interprets the description, generates JavaScript class overrides for each piece, and writes a human-readable summary. No coding required — just describe what you want ("the knight can teleport to any empty square once per game") and the agent handles the rest.
# how it works
1
Player opens
/create and chats with the AI agent in freeform — no structured prompts
↓
2
Agent outputs structured JSON: lobby name +
CustomPieceDefinition[] with JS code and plain-English summaries
↓
3
Code is syntax-checked client-side, lobby saved to SQLite — reusable by anyone
↓
4
On game start, piece definitions are sent to both players via WebSocket and evaluated in a sandboxed
Function constructor
# technical highlights
- Piece logic runs entirely client-side in a restricted sandbox — no access to
window,document, or network APIs - Server only syncs game state via WebSocket; it never executes user-generated code
- Lobbies persist after games end and can be browsed and re-joined by other players
- The agent is given the full
Pieceabstract interface in its system prompt to ensure generated code always conforms
# stack
Frontend
React · TypeScript · Vite
Backend
Node.js · Express · WebSockets
AI
OpenAI GPT-4o
Database
SQLite (better-sqlite3)
Infra
Docker · Docker Compose