gpt55-x402-gateway

x402 MCP First Purchase Kit

Use this page when an MCP client, agent runtime, or Flowise builder wants to evaluate the GPT-5.5 x402 MCP integration kit before paying.

Live Assets

• Product page: https://gpt55.558686.xyz/x402/mcp-first-purchase-kit
• Product JSON: https://gpt55.558686.xyz/x402/mcp-first-purchase-kit.json
• Paid endpoint: https://gpt55.558686.xyz/v1/tools/x402-mcp-integration-kit
• GitHub example: https://github.com/go165/gpt55-x402-gateway/tree/main/examples/mcp-first-purchase-kit
• x402 discovery: https://gpt55.558686.xyz/.well-known/x402
• Live prices: https://gpt55.558686.xyz/x402/live-prices.json

Quote-only Check

This command intentionally omits payment headers. It should return HTTP 402 with a live x402 quote.

curl -i "https://gpt55.558686.xyz/v1/tools/x402-mcp-integration-kit?base_url=https%3A%2F%2Fgpt55.558686.xyz&service_name=GPT-5.5%20x402%20Gateway&max_usdc_per_call=0.01&preferred_endpoint=https%3A%2F%2Fgpt55.558686.xyz%2Fv1%2Fpaid%2Fx402-seller-mini-check"

Expected policy values:

• amount: 6000 atomic USDC
• price: $0.006
• network: eip155:8453
• payTo: 0x1f0130669ca6fd02e025a984cc038f139df19a2f
• payment sent by this check: false

Run The Example

node examples/mcp-first-purchase-kit/check-mcp-first-purchase.mjs

The example fetches public JSON and an unauthenticated HTTP 402 quote. It does not use private keys, sign, pay, broadcast, register, or do KYC.

Paid Result Shape

The paid result is designed to answer the buyer’s immediate MCP integration question, not just prove payment. It should provide:

• remote MCP URL and service metadata
• x402 discovery, pricing, and OpenAPI links
• quote test commands for buyer-owned clients
• spend cap and payTo verification guidance
• integration checklist for MCP clients, Flowise builders, and agent runtimes

GitHub expected result shape: https://github.com/go165/gpt55-x402-gateway/blob/main/examples/mcp-first-purchase-kit/paid-result-shape.json

Only externally settled x402 payments from non-self buyers count as revenue. Quote-only runs are not revenue.

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