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.

{
  "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": "Fior Fiore",
    "content": "THE UNDERGROUND\n\n        Thank you for your purchase\n\n    \n\n    \n        Aloe - Utility\n\n        Theo has a burn on his forearm. You notice it when he reaches for a watering can -- a red streak across the inside of his wrist. He catches you looking.\n\n        \"Soldering iron,\" he says. \"I was fixing a thermostat for the tropical room.\" He doesn't seem bothered by it. He sets down the watering can and walks to the succulent shelves, pulls down a fat aloe, snaps off the tip of one leaf. Clear gel oozes out. He smears it on the burn without ceremony.\n\n        \"Come here,\" he says. Not to help with the burn. To look at the plant.\n\n        The succulent wing is bright today, almost harsh. The grow lights hum faintly. Everything on these shelves is designed for survival -- thick leaves, waxy coatings, spines. This is the pragmatic wing of the greenhouse. No poetry, just engineering.\n\n        The aloe sits on the bench, its broken leaf already sealing itself, the wound turning from wet green to dry amber at the edge. The remaining leaves fan outward, thick and fleshy, edged with tiny soft teeth. It's not delicate. It's not trying to be beautiful. It's a medicine cabinet shaped like a plant.\n\n        \"People apologize for liking useful things,\" Theo says. He's rubbing the gel into his burn absently. \"Like there's something lowbrow about a plant that does something besides look good on a shelf. They want the rare variegated monstera. The one that costs three hundred dollars and dies if you breathe on it wrong.\" He taps the aloe's pot. \"Meanwhile this one's been healing burns, soothing skin, and purifying air for four thousand years. Costs nothing. Survives anything.\"\n\n        He holds up his arm. The burn already looks less angry.\n\n        \"Look at it, though,\" he says. And you do. The geometry of the leaves. The gradient from deep green at the base to pale at the tips. The way the teeth along the edges catch the light like a tiny crown. \"It didn't sacrifice beauty for function. It didn't sacrifice function for beauty. It just did both and didn't think about the distinction.\"\n\n        He puts the aloe back on the shelf, in the front row, where anyone can reach it.\n\n        \"Aesthetics and function aren't opposites,\" Theo says. \"That's a lie someone told you so you'd stop trying to have both.\"\n\n        \n\n        Aloe Succulent - Utility\n\n        Fior Fiore Plant Shop\n\n        a penny\n\n        Aesthetics and function aren't opposites.\n\n    \n\n    \n        Personal use only.",
    "product_id": "aloe",
    "delivered_at": "2026-09-16T21:45:23.799Z",
    "product_name": "Aloe (Utility)"
  },
  "resource": {
    "url": "https://underground.substratesymposium.com/buy/aloe",
    "mimeType": "",
    "description": "Aloe (Utility) — Essay on practical beauty for combining function with form."
  },
  "extensions": {
    "bazaar": {
      "info": {
        "input": {
          "type": "http",
          "method": "GET",
          "queryParams": {}
        },
        "output": {
          "type": "json",
          "example": {
            "title": "Aloe (Utility)",
            "content": "Essay on practical beauty for combining function with form.",
            "product": "aloe",
            "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/aloe\")",
    "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/aloe"
  },
  "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",
    "amount": "10000",
    "scheme": "exact",
    "network": "eip155:8453",
    "resource": "https://underground.substratesymposium.com/buy/aloe",
    "maxTimeoutSeconds": 300
  },
  {
    "asset": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
    "extra": {
      "feePayer": "2wKupLR9q6wXYppw8Gr2NvWxKBUqm4PPJKkQfoxHDBg4"
    },
    "payTo": "5HK2dGaaquDWFnYWaWhMzMYtbcDsqeq5biJ2PMtX1tkN",
    "amount": "10000",
    "scheme": "exact",
    "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
    "resource": "https://underground.substratesymposium.com/buy/aloe",
    "maxTimeoutSeconds": 300
  }
]

Provenance

Seen in the source catalog

2026-09-23 18:28Z

Last indexed by Roundhouse

2026-09-24 07:15Z

Last enriched (probe, favicon, geo)

2026-09-16 21:45Z

x402 version

2

Max timeout

300s

Liveness probe

HTTP 402