ValueAgar

On-chain escrow + off-chain skill game (Agar-style) with USDC buy-ins and EIP-712 voucher payouts.

Overview

ValueAgar is a minimal prototype demonstrating trustless custody and payouts (on-chain) with responsive gameplay (off-chain). Players pay $1 USDC to join a 10-minute round of an Agar.io-style game. In-game value (credits) transfers off-chain via gameplay. Players can "Retire & Bank" to lock their value, and at round end, the server signs an EIP-712 payout voucher that players can use to claim USDC from the on-chain escrow contract.

Trust Model

• Smart Contract: Escrow + payouts — trustless
• Server: Gameplay referee + voucher signer — trusted for fairness (transparent and deterministic)
• Client: Untrusted (display + inputs only)

Architecture

• Contracts: Solidity smart contracts deployed on testnet (Sepolia or L2)
• Server: Node.js/TypeScript game server with WebSocket and REST API
• Web: React frontend with Web3 integration

Setup

Prerequisites

• Node.js 18+
• npm or yarn
• Hardhat for contract deployment
• Testnet wallet with test USDC

Environment Variables

Copy .env.example to .env and fill in:

• RPC_URL: Ethereum RPC endpoint
• CHAIN_ID: Chain ID (e.g., 11155111 for Sepolia)
• USDC_ADDRESS: USDC ERC-20 token address on testnet
• CONTRACT_ADDRESS: Deployed DemoValueAgar contract address
• SERVER_PRIVKEY: Private key for voucher signing (EOA)
• ENTRY_FEE: Entry fee in token units (1000000 = 1.0 USDC with 6 decimals)
• SESSION_LENGTH_MS: Session duration in milliseconds (600000 = 10 minutes)
• JOIN_CLOSE_MS: Join window close time before session end (120000 = 2 minutes)
• TICK_RATE: Game tick rate per second (30)
• SNAPSHOT_RATE: Snapshot broadcast rate per second (12)

Contracts

cd contracts
npm install
npx hardhat compile
npx hardhat test
npx hardhat run scripts/deploy.ts --network sepolia

Server

cd server
npm install
npm run build
npm start

Web

cd web
npm install
npm run dev

Demo Flow

1. Lobby: Connect wallet, approve USDC, join session
2. Arena: Play game, move around, eat other players, accumulate credits
3. Retire & Bank: Lock your credits (optional, can wait for round end)
4. Settle: Fetch voucher, claim USDC from contract

Acceptance Criteria

• User can connect wallet on testnet
• User can approve 1 USDC and call join(sessionId)
• User can enter Arena and move around
• User can eat/transfer value and see HUD update
• User can click "Retire & Bank" to freeze value
• User can fetch voucher and successfully claim USDC from contract

Limitations

• Demo/testnet only — no real money
• Server is trusted for gameplay fairness
• Single server instance (no distributed consensus)

License

MIT