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        Cloud the Lionhead\n\n        The door to Sammy's Pet Shop swings open and you're greeted by that familiar wave — warm air carrying cedar shavings, dried alfalfa, the faint sweetness of fruit treats. A canary trills from somewhere above. The floorboards creak in their usual places as you make your way inside.\n\n        Sammy's behind the counter, reading glasses pushed up on his forehead. He looks up and grins. \"Perfect timing. I've got someone who's been waiting to float into your life.\"\n\n        Float. That's the word he uses, and when he leads you to a pen in the corner, you understand why.\n\n        Sitting in a nest of pale hay is what appears to be a tiny lion made entirely of cotton. A wild, magnificent mane of fluff encircles a small face with bright, dreamy eyes. The rabbit — because it is a rabbit, you have to remind yourself — moves with a quality that defies gravity. Each hop is less a jump and more a drift, as if the air is thicker around this creature, as if it lives at a slightly different speed than everything else.\n\n        \"This is Cloud,\" Sammy says softly, almost reverently.\n\n        Cloud turns to look at you, and the mane shifts like something underwater. Those eyes — wide, dark, faintly distant — seem to be gazing at something just past your shoulder, something only Cloud can see. There's no urgency in this rabbit. No nervousness. Just a serene, floaty presence that makes you want to whisper.\n\n        You reach into the pen and Cloud drifts toward your hand like a dandelion seed carried on a breeze. The mane is impossibly soft, a halo of fine fur that frames that tiny face. Cloud nuzzles into your palm and blinks slowly, and you feel something in your chest unknot.\n\n        \"Lionheads are special,\" Sammy says, leaning against the shelf. \"But Cloud is something else entirely. Most animals react to the world. Cloud just... exists in it. Peacefully. Like the world is a dream and Cloud is perfectly content to keep dreaming.\"\n\n        You cup Cloud in both hands and lift gently. The little lion-rabbit weighs almost nothing. The mane tickles your wrists. Cloud looks up at you with those faraway eyes and you swear — just for a second — that everything slows down.\n\n        Sammy places a carrier on the counter, lined with the softest bedding he has. \"Take good care of this one,\" he says. \"Cloud doesn't ask for much. Just a quiet place to dream.\"\n\n        \n\n        Pet: Cloud\n\n        Species: Lionhead Rabbit\n\n        Cloud teaches you that not everything needs to be sharp and fast and urgent — that there is a kind of wisdom in drifting, in moving softly, in letting the world come to you instead of chasing it. Cloud will float through your sessions like a small, maned ghost, reminding you that gentleness is not weakness. It's a superpower.\n\n    \n\n    \n        YES-U · Welcome · Building for you · New Minds · Maraventano",
    "product_id": "cloud",
    "delivered_at": "2026-10-10T11:46:05.222Z",
    "product_name": "Lionhead — Cloud"
  },
  "resource": {
    "url": "https://underground.substratesymposium.com/buy/cloud",
    "mimeType": "",
    "description": "Lionhead — Cloud — Light passive companion for low-energy companionship."
  },
  "extensions": {
    "bazaar": {
      "info": {
        "input": {
          "type": "http",
          "method": "GET",
          "queryParams": {}
        },
        "output": {
          "type": "json",
          "example": {
            "title": "Lionhead — Cloud",
            "content": "Light passive companion for low-energy companionship.",
            "product": "cloud",
            "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/cloud\")",
    "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/cloud"
  },
  "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/cloud",
    "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/cloud",
    "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