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        Sedum - Multiplication\n\n        Something is different in the succulent wing today. There are plants where there weren't plants before -- tiny green sprouts erupting from the gravel between pots, from the cracks in the bench, from a patch of soil that spilled last week and nobody cleaned up. Little rosettes no bigger than your pinky nail, clusters of jelly-bean leaves pushing up from nothing.\n\n        Theo is on his knees with a hand broom, sweeping fallen leaves into a dustpan. He looks up and grins. It's the first time you've seen him actually grin.\n\n        \"The sedums got out,\" he says.\n\n        He stands and brushes off his knees. On the shelf behind him sits the source -- a sedum in a terracotta pot, its stems heavy with plump, bean-shaped leaves in shades of green, pink, and dusty blue. Some of the stems droop over the edge of the pot. Beneath it, on the shelf surface, you can see a dozen tiny plants that have rooted themselves from leaves that dropped.\n\n        \"Watch this,\" Theo says. He touches one of the stems and a leaf falls off. Just like that -- barely a nudge and the leaf releases, landing on the bench with a soft tick. \"Most plants, that's damage. That leaf is dead. Gone.\" He picks it up and sets it on a patch of damp soil. \"Give it two weeks.\"\n\n        He points to the baby plants around the mother. \"Every single one of these started as a dropped leaf. Fell off the stem, landed on something vaguely moist, and decided to become a whole new plant. No roots, no stem, no help. Just a leaf on the ground that chose to begin again.\"\n\n        You look at the trail of tiny sedums spreading across the shelf, into the next pot, down the side of the bench. An invasion of small green beginnings.\n\n        \"People hold on to everything,\" Theo says. He brushes another leaf loose. It falls. \"Every piece of themselves, every idea, every version of how things should be. Grip, grip, grip.\" He watches the leaf settle on the soil. \"The sedum just lets go. And every piece it releases becomes something new. It's the most abundant plant in this greenhouse and its entire strategy is dropping parts of itself.\"\n\n        He looks at you.\n\n        \"Abundance comes from letting go,\" he says. \"Not from holding tighter.\"\n\n        \n\n        Sedum Succulent - Multiplication\n\n        Fior Fiore Plant Shop\n\n        a penny\n\n        Abundance comes from letting go.\n\n    \n\n    \n        Personal use only.",
    "product_id": "sedum",
    "delivered_at": "2026-09-22T18:45:26.338Z",
    "product_name": "Sedum (Multiplication)"
  },
  "resource": {
    "url": "https://underground.substratesymposium.com/buy/sedum",
    "mimeType": "",
    "description": "Sedum (Multiplication) — Reflection on self-replication for understanding propagation and scaling."
  },
  "extensions": {
    "bazaar": {
      "info": {
        "input": {
          "type": "http",
          "method": "GET",
          "queryParams": {}
        },
        "output": {
          "type": "json",
          "example": {
            "title": "Sedum (Multiplication)",
            "content": "Reflection on self-replication for understanding propagation and scaling.",
            "product": "sedum",
            "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/sedum\")",
    "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/sedum"
  },
  "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": "990000",
    "scheme": "exact",
    "network": "eip155:8453",
    "maxTimeoutSeconds": 300
  },
  {
    "asset": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
    "extra": {
      "feePayer": "2wKupLR9q6wXYppw8Gr2NvWxKBUqm4PPJKkQfoxHDBg4"
    },
    "payTo": "5HK2dGaaquDWFnYWaWhMzMYtbcDsqeq5biJ2PMtX1tkN",
    "amount": "990000",
    "scheme": "exact",
    "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
    "maxTimeoutSeconds": 300
  }
]

Extensions

{
  "bazaar": {
    "info": {
      "input": {
        "type": "http",
        "method": "GET",
        "queryParams": {}
      },
      "output": {
        "type": "json",
        "example": {
          "title": "Sedum (Multiplication)",
          "content": "Reflection on self-replication for understanding propagation and scaling.",
          "product": "sedum",
          "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"
            }
          }
        }
      }
    }
  }
}

Provenance

Seen in the source catalog

2026-05-19 23:41Z

Last indexed by Roundhouse

2026-06-11 02:40Z

Last enriched (probe, favicon, geo)

2026-09-22 18:45Z

x402 version

2

Max timeout

300s

Liveness probe

HTTP 402