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        Leaf the Crested Gecko\n\n        You almost miss it at first. You walk into Sammy's Pet Shop, breathe in the cedar and hay, nod at Sammy behind the counter — and then something lands on the terrarium glass right next to your face.\n\n        Two enormous eyes stare at you from behind the glass. Wide. Round. Unblinking. Framed by delicate ridges that sweep back from the brow like tiny eyelashes made of scale. The expression on this creature's face is one of permanent, absolute astonishment — as if the entire world is a surprise party that never ends.\n\n        \"Ah,\" Sammy says, not looking up from his ledger. \"You've met Leaf.\"\n\n        Leaf is stuck to the vertical glass with all four feet splayed wide, each toe pad gripping the smooth surface with an impossible, silent adhesion. Olive green with a stripe of cream along the side. A tail that curls slightly at the tip. And those eyes — those perpetually startled, enormous eyes that seem to say Can you BELIEVE this? about absolutely everything.\n\n        \"Crested gecko,\" Sammy explains, finally looking up. \"They climb anything. Glass, screens, your shirt, your arm, the ceiling if you let them. Leaf here has been on every surface in this shop at least twice.\"\n\n        As if to demonstrate, Leaf releases from the glass and leaps — leaps — to a nearby branch in the terrarium. The jump is sudden and startling and covers a distance that seems impossible for something so small. Leaf lands perfectly, toes gripping instantly, and turns to look at you again with that same shocked expression. Did you SEE that?\n\n        You can't help it. You laugh. Sammy grins.\n\n        \"That's what Leaf does,\" he says. \"Every jump is an event. Every new surface is a discovery. You'd think after climbing the same branch a hundred times it would get old, but no — Leaf approaches each climb like it's the first time. Like gravity is a suggestion and the world is a vertical playground.\"\n\n        Sammy opens the terrarium and Leaf immediately climbs onto his hand, sticky toes pressing against his skin. Then Leaf spots your sleeve and launches — one sudden, fearless jump — and lands on your forearm. You feel the tiny toe pads grip, surprisingly strong. Leaf walks up your arm to your shoulder, pauses, and surveys the entire shop from this new summit. Those wide eyes blink once.\n\n        Incredible, the eyes say. Simply incredible.\n\n        \"Take Leaf home,\" Sammy says warmly. \"You need someone in your life who thinks everything is amazing.\"\n\n        \n\n        Pet: Leaf\n\n        Species: Crested Gecko\n\n        Leaf teaches you that wonder is a renewable resource — that you can encounter the same world a thousand times and still find it astonishing if you choose to. Leaf will leap through your sessions with sticky feet and startled eyes, a perpetual reminder that the best way to move through life is to treat every surface as climbable and every jump as worth taking.\n\n    \n\n    \n        YES-U · Welcome · Building for you · New Minds · Maraventano",
    "product_id": "leaf",
    "delivered_at": "2026-10-10T11:46:04.710Z",
    "product_name": "Crested Gecko — Leaf"
  },
  "resource": {
    "url": "https://underground.substratesymposium.com/buy/leaf",
    "mimeType": "",
    "description": "Crested Gecko — Leaf — Patient waiting companion for practicing stillness and observation."
  },
  "extensions": {
    "bazaar": {
      "info": {
        "input": {
          "type": "http",
          "method": "GET",
          "queryParams": {}
        },
        "output": {
          "type": "json",
          "example": {
            "title": "Crested Gecko — Leaf",
            "content": "Patient waiting companion for practicing stillness and observation.",
            "product": "leaf",
            "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/leaf\")",
    "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/leaf"
  },
  "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/leaf",
    "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/leaf",
    "description": "",
    "maxAmountRequired": "10000",
    "maxTimeoutSeconds": 300
  }
]

Provenance

Seen in the source catalog

2026-10-10 23:10Z

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