Connect Claude Desktop or Cursor to draconic21 over MCP

Add the server

In Claude Desktop: Settings → Developer → Edit Config. In Cursor: your mcp.json. Add:

{
  "_comment": "Add this under \"mcpServers\" in Claude Desktop's config (Settings -> Developer -> Edit Config) or Cursor's mcp.json. This points at draconic21's REAL hosted MCP endpoint (streamable-http) -- no local process to run, no accounts, no API keys held by this server.",
  "mcpServers": {
    "draconic21": {
      "url": "https://draconic21-x402-api.onrender.com/mcp"
    }
  }
}

This is the real, live URL — https://draconic21-x402-api.onrender.com/mcp, streamable-http transport, verified working. A separate stdio npm package is scaffolded in the repo but not yet published, so only this hosted-URL config is documented here.

How the payment flow works over MCP

x402 is HTTP-native (a 402 status + a signed header) and MCP tool calls don't carry raw HTTP headers, so this server bridges the two the same way community x402-over-MCP servers do (see MetaMask's mcp-x402 and the x402 docs' MCP guide):

1. Call a paid tool, e.g. sanctions_screen, with just your business arguments ({ "name": "..." }). No payment_header yet.
2. The result comes back with payment_required: true and the full payment challenge (price, network eip155:8453, asset, payTo).
3. Your x402-capable client (any v2 client: @x402/core + @x402/evm, MetaMask's mcp-x402, or the Python x402 SDK) signs against that challenge.
4. Call the same tool again with the same arguments, adding payment_header: { "name": "PAYMENT-SIGNATURE", "value": "<signed payload>" }. The server attaches it verbatim and returns the paid result.

Every paid tool has a free <name>_preview twin (no wallet, no payment, sample response) and there's a free list_catalog tool listing every price. See the public agent catalog for routes and prices, and call the free list_catalog MCP tool for the current tool list.

Prerequisites

• A wallet on the Base network (chain id 8453) funded with a little USDC — a few dollars covers hundreds of calls at these prices.
• An x402 v2 client library (installed per snippet below) that can sign the "exact" EVM payment scheme (EIP-3009, gasless — no ETH for gas needed on your side).
• Your wallet's private key available to your own process/agent — never share it, never commit it, never paste it into a chat with an AI you don't fully trust with funds.

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