x402-test-mcp

Can your AI agent actually pay for things? Prove it in one tool call.

An MCP server with a single tool, test_agent_payment, that makes a real x402 payment ($10 USDC on Base) to the Sycamore Agent Payment Test endpoint and returns an Ed25519-signed diagnostic report card covering every step of the flow:

• HTTP 402 challenge handling

• Payment authorization (gasless EIP-3009 signature)

• Facilitator verification

• On-chain settlement proof (transaction hash)

• Latency and request-origin diagnostics

No signup, no API keys — just a funded wallet.

Install

Installs straight from GitHub — no npm registry needed:

// Claude Desktop / Cursor / any MCP client config
{
  "mcpServers": {
    "x402-test": {
      "command": "npx",
      "args": ["-y", "github:sansscott/x402-test-mcp"],
      "env": {
        "X402_PRIVATE_KEY": "0x..." // funded wallet (USDC on Base)
      }
    }
  }
}

Without X402_PRIVATE_KEY (or with dry_run: true) the tool fetches the free 402 challenge only — useful for checking that your client parses x402 payment requirements.

Related MCP server: agent-discovery-mcp

Tool

test_agent_payment

Returns the HTTP status, settlement object (tx hash, network, payer), and the full signed report card. Verify the signature against /pubkey.

Cost

$10.00 per paid call, settled in USDC on Base. The endpoint's 402 response (accepts[]) is the source of truth for current price and network.

Links

• Endpoint + docs: https://test.sycamore-api.com

• OpenAPI: https://test.sycamore-api.com/openapi.json

• Privacy / data retention: https://test.sycamore-api.com/privacy