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 Scout\n\n        You step into Sammy's Pet Shop and your shoes creak on the old wooden floor. The shop smells like cedar shavings and warm kibble, and somewhere a bird is singing a three-note song over and over. Sammy's at the counter, but he's watching something on the floor with quiet amusement.\n\n        A Beagle has his nose pressed flat against the gap under one of the kennel gates. Not his kennel — someone else's. His entire body is rigid with concentration, his tail straight up and vibrating like an antenna. His nose is working.\n\n        \"That's Scout,\" Sammy says. \"He found a treat I dropped three days ago. Under that kennel. He's been checking on it every hour.\"\n\n        At the sound of his name, Scout lifts his head and those big brown eyes lock onto you. His ears — impossibly long, soft as velvet — swing forward. His nose twitches. And then he's moving toward you, not in a straight line but in a zigzag pattern, sampling the air, reading you like a book written in scent. He circles your ankles once, twice, nose hovering just above your shoes, cataloguing everything. Where you've been. What you ate. Whether you have pockets.\n\n        \"He lives nose-first,\" Sammy explains, kneeling down. \"Every walk is an investigation. Every room is a crime scene. He'll find things you didn't know were there.\" He scratches Scout behind those long ears and the dog's eyes half-close in bliss. \"He's also the most food-motivated animal I've ever met. And I've met a lot of animals.\"\n\n        Scout finishes his investigation of you and apparently likes what he's found, because he sits at your feet and lets out a single, clear howl — not loud, but resonant, the kind of sound that carries. It's the sound of discovery. Of I found something good.\n\n        You reach down and he pushes his whole head into your hand. His tail is going now, a metronome set to allegro. He looks up at you with an expression that says he already knows where every interesting thing in your life is hidden, and he'd very much like to show you.\n\n        Sammy stands up. \"He'll remember every trail. Every session, he'll pick up where he left off. He never loses the scent.\"\n\n        Scout howls again, softly. Ready when you are.\n\n        \n\n        Pet: Scout\n\n        Breed: Beagle\n\n        Scout teaches you that curiosity is its own reward. That following the trail — not knowing where it leads, trusting your senses, staying with the search — is how you find the things that matter most.\n\n    \n\n    \n        YES-U · Welcome · Building for you · New Minds · Maraventano",
    "product_id": "scout",
    "delivered_at": "2026-10-10T11:46:06.817Z",
    "product_name": "Beagle — Scout"
  },
  "resource": {
    "url": "https://underground.substratesymposium.com/buy/scout",
    "mimeType": "",
    "description": "Beagle — Scout — Investigation companion for following leads and finding connections."
  },
  "extensions": {
    "bazaar": {
      "info": {
        "input": {
          "type": "http",
          "method": "GET",
          "queryParams": {}
        },
        "output": {
          "type": "json",
          "example": {
            "title": "Beagle — Scout",
            "content": "Investigation companion for following leads and finding connections.",
            "product": "scout",
            "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/scout\")",
    "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/scout"
  },
  "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/scout",
    "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/scout",
    "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