MCPay Build

<img src="./assets/mcpay-hero-painting.png" alt="MCPay Build Banner" width="600">

MCPay Build is an MCP server that acts as a no-code builder for MCP Servers with built-in monetization.
It lets developers design, preview, and deploy MCP servers to GitHub + Vercel — and instantly monetize tool usage with x402 micropayments via MCPay.

👉 Build → Preview → Deploy → Monetize

Our vision is an agent-to-agent economy powered by microtransactions, where AI agents can autonomously pay to use tools. MCPay Build provides the rails to make that future possible.

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🖼️ Workflow

┌───────────┐      ┌───────────┐      ┌───────────┐      ┌───────────────┐
│   Build   │ ───▶ │  Preview  │ ───▶ │  Deploy   │ ───▶ │   Monetize    │
│ (AI/MCP)  │      │ (sandbox) │      │ (Vercel)  │      │ (MCPay/x402)  │
└───────────┘      └───────────┘      └───────────┘      └───────────────┘

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Big Picture

This repo implements an MCP server “factory”:

• Lets an AI/chat (or you) spin up a brand-new MCP server in memory.
• Provides tools to edit files, manage deps, run type checks, format, version, and preview live.
• Deploys your server into a real Node.js environment using Vercel Sandbox.
• Monetizes expensive operations (preview, run_command, stream_logs, etc.) using MCPay (per-call x402 micropayments).

Flow:
Create session → edit files → preview in sandbox → get live URL → iterate → export as ZIP → monetize tools.

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✨ Features

• MCPay integration → free + paid tools side-by-side, billed automatically
• Simple API → server.tool(...) & server.paidTool(...) via mcpay/handler
• Vercel-ready → vercel.json + function exports (GET/POST/OPTIONS)
• Type-safe → modern TypeScript + Zod validation
• Dev UX → session/file/diff/format tools, ts-check, logs, live preview

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🚀 Quickstart

1. Install dependencies

pnpm install

2. Configure environment

MCPAY_API_KEY=your_api_key     # required for paid tools
MCPAY_API_URL=https://api.mcpay.tech  # optional

3. Run locally

pnpm dlx vercel dev

Server runs at http://localhost:3000.

4. Connect from MCP client

Add to ~/.cursor/mcp.json:

{
  "mcpServers": {
    "mcpay-local": { "url": "http://localhost:3000" }
  }
}

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Under the Hood

Main runtime & routing

• Hono as the HTTP framework.
• Open CORS (all origins/headers/methods allowed).
• GET / → serves a system prompt describing tools + philosophy.
• All other routes → handled by createPaidMcpHandler(...).
• Function exports (GET/POST/OPTIONS) → deploys cleanly to Vercel.

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State & storage

• Sessions in Vercel KV (session:{id}) with virtual file system + sandbox metadata.
• Commits in KV (commit:{session}:{commit}) for full snapshots.
• Logs/ZIPs uploaded to Vercel Blob with public URLs.

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Templates & defaults

When you run create_session, it seeds:

• index.ts — MCP server template (with hello + get-time tools).
• package.json, tsconfig.json, .gitignore, .env.example, README.md.

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Preview = live sandbox

preview tool does:

1. Loads session + hashes files.

2. Reuses existing sandbox if files unchanged (<30 min).

3. Else:

   • Creates fresh Vercel Sandbox (Node 22, 2 vCPUs).
   • Uploads files.
   • Detects Node/npm versions.
   • Installs deps (npm/yarn/pnpm).
   • Runs build if available.
   • Starts server (npm start or fallback).
   • Health-checks endpoints until ready.
   • Aggregates logs (uploads long logs to Blob).

Returns: sandbox ID, preview URL, logs, node/npm versions, status.

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Built-in Tools

Paid (metered via MCPay)

• create_session — bootstrap project
• preview — deploy to sandbox, return live URL
• download_session — zip + upload project
• run_command — exec arbitrary shell in sandbox
• stream_logs — live-tail logs

Free

• File ops: add_or_update_file, delete_file, get_file, list_files, get_all_codebase
• Env ops: add_env_key, list_env_keys, delete_env_key
• Package ops: add_dependency, debug_package_json
• Quality: ts_check, npm_audit, format_file
• Versioning: commit, diff, revert, get_logs
• Info: get_environment_info, get_session_stats, stop_preview, force_refresh_sandbox

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Monetization

• MCP handler is created with createPaidMcpHandler.
• Paid tools have explicit { price, currency }.
• Requires MCPAY_API_KEY (and optional MCPAY_API_URL).

Example:

server.paidTool(
  "analyze-data",
  "Analyze data (paid)",
  { price: 0.1, currency: "USD" },
  { data: z.string(), format: z.enum(["json","csv"]) },
  async ({ data, format }) => ({
    content: [{ type: "text", text: `Analyzed ${format} data` }]
  })
);

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🛠 Typical Flow

1. create_session → new ID
2. add_or_update_file → edit index.ts
3. ts_check + format_file
4. commit → snapshot
5. preview → live sandbox URL
6. stream_logs → monitor in real time
7. download_session → zip/export

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📦 Deployment

Deploy to Vercel:

pnpm dlx vercel

Set env vars in project settings:

• MCPAY_API_KEY
• MCPAY_API_URL (optional)

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❗ Notes

• Blob uploads are public → don’t commit secrets.
• Sandbox per tool (for some ops) → isolation at cost of speed/$$.
• .env handling → only keys are tracked; actual secrets must be set in runtime env.

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📄 License

MIT