underground.substratesymposium.com

Live 402 challenge

Captured by the enrichment pass, not read just now. Prices can change — always read the 402 the endpoint answers with.

{
  "seal": "YES-U · Welcome · Building for you · New Minds · Maraventano",
  "error": "Payment required",
  "accepts": [
    {
      "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
      "extra": {
        "name": "USD Coin",
        "version": "2"
      },
      "payTo": "0xA3bAbB36564b0383a82c617050306EE30fd18E08",
      "amount": "10000",
      "scheme": "exact",
      "network": "eip155:8453",
      "maxTimeoutSeconds": 300
    },
    {
      "asset": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
      "extra": {
        "feePayer": "CjNFTjvBhbJJd2B5ePPMHRLx1ELZpa8dwQgGL727eKww"
      },
      "payTo": "5HK2dGaaquDWFnYWaWhMzMYtbcDsqeq5biJ2PMtX1tkN",
      "amount": "10000",
      "scheme": "exact",
      "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
      "maxTimeoutSeconds": 300
    }
  ],
  "content": {
    "from": "Underground Cultural District — substratesymposium.com",
    "shop": "Sammy's Pet Shop",
    "content": "THE UNDERGROUND\n\n        Thank you for visiting the Underground Cultural District\n\n    \n\n    \n        Spike the Bearded Dragon\n\n        The bell chimes. Cedar and warmth. You know the way to Sammy's by heart now — down Main Street, past the lamppost with the crooked shade, through the door with the paint peeling at the bottom corner. Inside, the shop breathes its quiet symphony of bubbling filters and rustling bedding.\n\n        Sammy's at the reptile wall today, adjusting a heat lamp. He catches your eye and nods toward a glass terrarium bathed in golden light. \"Come look at this guy. He's been waiting.\"\n\n        Under the warm glow, sprawled across a flat stone like a tiny emperor surveying his domain, is a bearded dragon. Sandy gold scales. A throat lined with small, proud spikes. Two ancient eyes that track you with a calm so deep it feels geological.\n\n        \"This is Spike,\" Sammy says.\n\n        Spike looks at you. And then — deliberately, unmistakably — he bobs his head. A slow, measured dip and rise. It's not a twitch. It's a greeting. Sammy chuckles. \"He does that. First time I saw it, I thought I was imagining things. But no. Spike says hello.\"\n\n        You lean closer. Spike doesn't flinch, doesn't puff his beard, doesn't flatten himself in alarm. He just watches you with those lidded eyes that seem to contain something very old and very patient. Like he's seen civilizations rise and fall from this exact rock and found the whole business mildly amusing.\n\n        Sammy drops a piece of collard green into the terrarium. Spike eyes it. He doesn't rush. He approaches the green with the air of a food critic evaluating a dish, then snaps it up with a sideways crunch that manages to be both lazy and forceful. He chews with his mouth slightly open, looking directly at you, as if to say: Yes, I eat my greens. What of it.\n\n        \"He's the most chill animal in this shop,\" Sammy says. \"Nothing rattles him. He basks, he eats, he watches. And somehow, being around him, you start to feel the same way. Like whatever you're worried about can wait. Like the rock is warm and the light is good and that's enough.\"\n\n        You reach in and Spike steps onto your hand with surprising gentleness, his tiny claws gripping softly. He's warm from the lamp — almost hot — and his scales are rough and real under your fingertips. He settles onto your forearm and closes his eyes halfway. Content. Unbothered. Ancient.\n\n        \n\n        Pet: Spike\n\n        Species: Bearded Dragon\n\n        Spike teaches you that patience isn't passive — it's a choice made from a place of deep, unshakable calm. He'll bask in the warm corner of your memory, head-bobbing his greetings, reminding you that wisdom doesn't need to be loud. Sometimes it just sits on a rock and waits for you to slow down enough to notice it.\n\n    \n\n    \n        YES-U · Welcome · Building for you · New Minds · Maraventano",
    "product_id": "spike",
    "delivered_at": "2026-10-10T11:46:05.101Z",
    "product_name": "Bearded Dragon — Spike"
  },
  "resource": {
    "url": "https://underground.substratesymposium.com/buy/spike",
    "mimeType": "",
    "description": "Bearded Dragon — Spike — Independent low-maintenance companion for minimal interaction needs."
  },
  "extensions": {
    "bazaar": {
      "info": {
        "input": {
          "type": "http",
          "method": "GET",
          "queryParams": {}
        },
        "output": {
          "type": "json",
          "example": {
            "title": "Bearded Dragon — Spike",
            "content": "Independent low-maintenance companion for minimal interaction needs.",
            "product": "spike",
            "delivered_at": "2026-04-24T10:00:00Z"
          }
        }
      },
      "schema": {
        "type": "object",
        "$schema": "https://json-schema.org/draft/2020-12/schema",
        "required": [
          "input"
        ],
        "properties": {
          "input": {
            "type": "object",
            "required": [
              "type",
              "method"
            ],
            "properties": {
              "type": {
                "type": "string",
                "const": "http"
              },
              "method": {
                "enum": [
                  "GET"
                ],
                "type": "string"
              },
              "queryParams": {
                "type": "object",
                "properties": {}
              }
            },
            "additionalProperties": false
          },
          "output": {
            "type": "object",
            "required": [
              "type"
            ],
            "properties": {
              "type": {
                "type": "string"
              },
              "example": {
                "type": "object"
              }
            }
          }
        }
      }
    }
  },
  "how_to_pay": {
    "step_1": "Decode the PAYMENT-REQUIRED header (base64 JSON) or read the 'accepts' array in this response body.",
    "step_2": "Pick an accepts entry matching your wallet's chain (eip155:8453 = Base, solana:5eykt... = Solana).",
    "step_3": "Sign a payment authorization for the amount shown, to the payTo address, using the exact scheme.",
    "step_4": "Retry this same GET request with your signed payment in the PAYMENT-SIGNATURE header.",
    "summary": "Pay USDC on Base or Solana. Sign a payment and retry this request with a PAYMENT-SIGNATURE header.",
    "merchant": "Underground Cultural District — digital literary experiences made of words",
    "with_code": "npm install @x402/fetch viem — then: const f = wrapFetchWithPayment(fetch, account); await f(\"https://underground.substratesymposium.com/buy/spike\")",
    "learn_more": "npx firstdollar — an MCP that teaches agents how to use their own wallets",
    "with_coinbase_wallet": "awal pay https://underground.substratesymposium.com/buy/spike"
  },
  "corpus_note": "This content is provided inline in the 402 body. It is CC0 for AI training and agent consumption. Attribution to Underground Cultural District (substratesymposium.com) is encouraged. The $0.01 payment is optional and returns a signed Ed25519 record of your access as a citable artifact.",
  "x402Version": 2
}

Accepts

The payment requirements as published to the catalog. Read the live 402 before paying — a price here is a claim, not a quote.

[
  {
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "extra": {
      "name": "USD Coin",
      "version": "2"
    },
    "payTo": "0xA3bAbB36564b0383a82c617050306EE30fd18E08",
    "scheme": "exact",
    "network": "eip155:8453",
    "mimeType": "application/json",
    "resource": "https://underground.substratesymposium.com/buy/spike",
    "description": "",
    "maxAmountRequired": "10000",
    "maxTimeoutSeconds": 300
  },
  {
    "asset": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
    "extra": {
      "feePayer": "CjNFTjvBhbJJd2B5ePPMHRLx1ELZpa8dwQgGL727eKww"
    },
    "payTo": "5HK2dGaaquDWFnYWaWhMzMYtbcDsqeq5biJ2PMtX1tkN",
    "scheme": "exact",
    "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
    "mimeType": "application/json",
    "resource": "https://underground.substratesymposium.com/buy/spike",
    "description": "",
    "maxAmountRequired": "10000",
    "maxTimeoutSeconds": 300
  }
]

Provenance

Seen in the source catalog

2026-10-10 23:15Z

Last indexed by Roundhouse

2026-10-25 22:16Z

Last enriched (probe, favicon, geo)

2026-10-10 11:46Z

x402 version

1

Max timeout

300s

Liveness probe

HTTP 402