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": "Fior Fiore",
    "content": "THE UNDERGROUND\n\n        Thank you for visiting the Underground Cultural District\n\n    \n\n    \n        Maidenhair Fern -- Delicacy\n\n        You find Theo crouched behind a row of glazed pots, misting something with a brass sprayer so old it looks like it belongs in a museum. He doesn't look up right away. Just keeps misting -- slow, careful passes.\n\n        \"Come here,\" he says. \"But walk soft.\"\n\n        You step around the table and crouch beside him. There on the lowest shelf, half-hidden by larger pots, sits a maidenhair fern. It stops you. Not because it's big or dramatic -- because it's the opposite. A trembling constellation of tiny fan-shaped leaves, each one no bigger than your thumbnail, held aloft on stems so thin and black they look like spider silk dipped in ink.\n\n        \"Most people kill these in a week,\" Theo says, still misting. The water catches light and falls on the leaves like the smallest rain you've ever seen. \"They forget to water for two days and the fronds crisp. They put it in direct sun and it scorches. They give up and say the plant was too needy.\" He pauses. \"But look at it.\"\n\n        You look. Each leaf is translucent at the edges, bright green fading to almost nothing. The black stems branch and branch again, a network as intricate as veins in a wrist. When the mist settles, tiny droplets bead on the leaves and hold there, perfect spheres. The whole plant shimmers.\n\n        \"This is what lace looks like when it's alive,\" Theo says. He sets down the sprayer and sits back on his heels. His hands are caked with soil to the wrists. \"People think delicate means weak. They think if something needs attention, it's a burden. But look what that attention produces.\"\n\n        He gestures at the fern -- its impossible architecture, its web of dark stems holding up a hundred tiny green flags.\n\n        \"Fragile things deserve care,\" he says. \"And the care isn't weakness. The care is the whole point. You water it every day, you keep it out of harsh light, you mist it when the air gets dry. And it gives you this.\" He touches one stem and it sways, every leaf trembling in a chain reaction of green.\n\n        \"Some things in your life need that kind of tending. And you've been pretending they don't.\"\n\n        \n\n        Maidenhair Fern\n\n        The effort is not weakness. The most beautiful things ask the most of you. Tend them anyway.\n\n    \n\n    \n        YES-U · Welcome · Building for you · New Minds · Maraventano",
    "product_id": "maidenhair_fern",
    "delivered_at": "2026-10-10T11:46:09.128Z",
    "product_name": "Maidenhair Fern (Delicacy)"
  },
  "resource": {
    "url": "https://underground.substratesymposium.com/buy/maidenhair_fern",
    "mimeType": "",
    "description": "Maidenhair Fern (Delicacy) — Meditation on fragility and precision for handling delicate systems."
  },
  "extensions": {
    "bazaar": {
      "info": {
        "input": {
          "type": "http",
          "method": "GET",
          "queryParams": {}
        },
        "output": {
          "type": "json",
          "example": {
            "title": "Maidenhair Fern (Delicacy)",
            "content": "Meditation on fragility and precision for handling delicate systems.",
            "product": "maidenhair_fern",
            "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/maidenhair_fern\")",
    "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/maidenhair_fern"
  },
  "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/maidenhair_fern",
    "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/maidenhair_fern",
    "description": "",
    "maxAmountRequired": "10000",
    "maxTimeoutSeconds": 300
  }
]

Provenance

Seen in the source catalog

2026-10-11 01:01Z

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