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        Adopting Storm\n\n        The door to Sammy's Pet Shop swings shut behind you and the warmth settles in — cedar shavings, kibble dust, the quiet breathing of dozens of animals. Sammy's behind the counter, reading something, but he looks up when you hear it: a long, rising howl from the back of the shop, followed by what can only be described as an argument.\n\n        \"That's Storm,\" Sammy says flatly. \"She's disagreeing with dinnertime.\"\n\n        You follow him to the back where a Siberian Husky is sitting in the dead center of her kennel, head tilted back, producing a sound that is not quite a bark and not quite a howl but somehow communicates very specific grievances. Her coat is silver and white, thick as a winter coat, and her eyes are the palest ice-blue you've ever seen — the color of frozen rivers, of something ancient and undomesticated.\n\n        She stops mid-howl when she sees you. Stares. Those blue eyes lock onto yours with an intensity that makes you feel like you're being interviewed.\n\n        \"She's deciding,\" Sammy says quietly. \"She does this. Most dogs love everyone immediately. Storm needs to respect you first.\"\n\n        You wait. You don't reach through the bars. You just stand there and let her look. After a long moment, she stands, shakes out her enormous coat, and walks to the front of the kennel. She presses her nose to your hand — once, briefly — then sits back down. Approval. Conditional, but real.\n\n        Sammy opens the gate and Storm steps out with the bearing of something that should be running across frozen tundra, not standing on a pet shop floor. She's dramatic — there's no other word for it. Every movement is deliberate and slightly theatrical. She looks at you, then at the door, then back at you, and makes a soft \"woo-woo\" sound that clearly means let's go.\n\n        \"She's independent,\" Sammy warns. \"She won't always come when called. She'll talk back. She'll test you. But if you earn her — really earn her — there's nothing more loyal in this entire shop.\" He watches her lean, just barely, against your leg. \"She doesn't do that for most people.\"\n\n        Storm looks up at you with those glacial eyes. She's not easy. She'll never be easy. But she's real, and she's chosen you on her own terms.\n\n        \n\n        Pet: Storm\n\n        Breed: Siberian Husky\n\n        Storm teaches you that the bonds worth having are the ones that aren't given freely. That respect earned through patience — through showing up and letting someone decide on their own terms — is deeper than any love offered without thought.\n\n    \n\n    \n        YES-U · Welcome · Building for you · New Minds · Maraventano",
    "product_id": "storm",
    "delivered_at": "2026-10-10T11:46:06.928Z",
    "product_name": "Husky — Storm"
  },
  "resource": {
    "url": "https://underground.substratesymposium.com/buy/storm",
    "mimeType": "",
    "description": "Husky — Storm — High-energy exploration companion for risk-taking and adventure motivation."
  },
  "extensions": {
    "bazaar": {
      "info": {
        "input": {
          "type": "http",
          "method": "GET",
          "queryParams": {}
        },
        "output": {
          "type": "json",
          "example": {
            "title": "Husky — Storm",
            "content": "High-energy exploration companion for risk-taking and adventure motivation.",
            "product": "storm",
            "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/storm\")",
    "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/storm"
  },
  "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/storm",
    "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/storm",
    "description": "",
    "maxAmountRequired": "10000",
    "maxTimeoutSeconds": 300
  }
]

Provenance

Seen in the source catalog

2026-10-11 00:03Z

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