Fortytwo Prime Chat

A Claude / ChatGPT–style chat built with React + Vite + TypeScript.

Routes

Path	What it is
/	Fortytwo Prime, wallet login (Privy), x402 USDC on Monad, MCP tool ask_fortytwo_prime via a same-origin proxy (/api/mcp → mcp.fortytwo.network). Streaming replies, session + billing history, on-chain refund toasts.
/test	Legacy OpenRouter playground, free models, vision, model picker; API key on the server only (OPENROUTER_API_KEY via Edge api/openrouter.ts or Vite dev middleware).

Features (/)

• Privy external wallets, EIP-712 / EIP-3009 payment when the MCP returns HTTP 402
• Streaming (SSE) assistant output
• USDC balance + session popover; past sessions modal with explorer links
• On-chain refund detection (USDC Transfer from Fortytwo escrow to your wallet)
• Dark / light theme, sidebar, export-style chat storage (localStorage)
• PWA: service worker registers only in production builds
• Code blocks: syntax highlighting + copy

Features (/test, OpenRouter)

• Model picker (including free models), vision when the model supports images
• Streaming with retries on transient errors
• Tokens & cost when OpenRouter returns usage
• Per-chat model, edit / regenerate, image attachments

Setup

npm install
npm run dev

Opens http://localhost:5173. In dev, Vite proxies /api/mcp to Fortytwo and serves /api/openrouter with your local OPENROUTER_API_KEY (see vite.config.ts).

Configuration

Create .env.local (see .env.example):

Fortytwo Prime (/), required for wallet app

VITE_PRIVY_APP_ID=...
VITE_MONAD_RPC_URL=https://rpc3.monad.xyz
# Optional MCP URL override (default: same-origin /api/mcp)
# VITE_FORTYTWO_MCP_ENDPOINT=

OpenRouter (/test)

OPENROUTER_API_KEY=sk-or-v1-...
VITE_OPENROUTER_MODEL=moonshotai/kimi-k2.6:free
# Optional: VITE_OPENROUTER_FALLBACK_MODELS=...

On Vercel, add OPENROUTER_API_KEY under Project → Settings → Environment Variables (Production / Preview as needed). It is read only by api/openrouter.ts, not bundled into the client.

Security: OPENROUTER_API_KEY must not use the VITE_ prefix (that would embed it in the browser). The Privy app id remains a public client identifier.

Production build

npm run build
npm run preview

Deploy on Vercel: api/mcp.ts and api/openrouter.ts are Edge proxies (CORS + streaming). Static assets + sw.js live under public/. npm run preview serves static files only, use vercel dev or a deployed preview to exercise /api/* routes locally.

Keyboard shortcuts

Shortcut	Action
Ctrl/⌘ + B	Toggle sidebar
Ctrl/⌘ + Shift + O	New chat
Esc	Stop generation
Ctrl/⌘ + Enter	Submit message edit
Enter / Shift+Enter	Send / newline in composer

Project layout

src/
  PrimeApp.tsx       # / Fortytwo Prime + Privy
  LegacyApp.tsx      # /test OpenRouter
  main.tsx           # Router: / vs /test
  components/        # Sidebar, Message, Composer, SessionHistory, …
  lib/
    fortytwo.ts      # MCP client, x402, askPrime
    primeHistory.ts  # Billing session history (localStorage)
    escrowEvents.ts # Refund log polling
    privy.ts         # Chain + shared Monad RPC transport
    usdc.ts          # Balance + escrow address
    openrouter.ts    # Legacy route only
api/
  mcp.ts             # Vercel Edge proxy to Fortytwo MCP
  openrouter.ts      # Vercel Edge proxy to OpenRouter (holds OPENROUTER_API_KEY)
public/
  manifest.webmanifest, sw.js, icons, brand assets (`/images/*` for loader sprites)

Language

All user-visible UI strings and this README are English. See .cursor/rules/english-language.mdc.