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        Lithops (Living Stones) - Patience\n\n        You've been coming back every few days. Theo has noticed. Today when you walk in he's standing by the door like he was waiting, arms folded, a look on his face that's half amusement, half concern.\n\n        \"You keep checking,\" he says.\n\n        You don't know what he means. Or you do, but you don't want to admit it. Something in your life isn't moving fast enough. You keep poking at it, refreshing it, watching for signs.\n\n        He leads you to the far end of the succulent wing, past the echeverias and the sedums, past the hanging string-of-pearls, to a bottom shelf near the floor. You have to crouch to see it. A shallow clay dish filled with what appears to be smooth pebbles -- grey, brown, some with faint green or purple tints, flat-topped and round. Gravel, you think.\n\n        \"Those are alive,\" Theo says.\n\n        You look closer. The pebbles have a faint slit across their tops. Some have subtle markings, almost like fingerprints, patterned into their surfaces. They're plants. Each one is a pair of thick, fused leaves masquerading as a stone.\n\n        \"Lithops,\" he says. \"Living stones. From the Namibian desert. They evolved to look like the ground so nothing would eat them. And they grow --\" he pauses, searching for the word \"-- almost not at all.\"\n\n        He picks one up. It's the size of a large marble. Heavy for its size.\n\n        \"I've had this tray for six years,\" Theo says. \"Six years. You know what's changed?\" He waits. \"Three of them split once and produced a new pair of leaves. That's it. That's six years of growth. If you watched this tray every single day, you would see nothing. Absolutely nothing. You'd think they were dead. You'd think you were doing something wrong.\"\n\n        He sets the lithops back in its place in the gravel, where it disappears again, indistinguishable from the stones around it.\n\n        \"But then one morning you come in and there's a flower. A bright yellow flower bigger than the entire plant, pushing up from that slit, and it's the most ridiculous, joyful thing you've ever seen. And you realize it was working the whole time. You just couldn't see it.\"\n\n        He stands, knees cracking.\n\n        \"Stop checking,\" Theo says. \"Growth happens when you're not watching.\"\n\n        \n\n        Lithops (Living Stones) - Patience\n\n        Fior Fiore Plant Shop\n\n        a penny\n\n        Stop checking. Growth happens when you're not watching.\n\n    \n\n    \n        Personal use only.",
    "product_id": "lithops",
    "delivered_at": "2026-09-22T18:45:26.981Z",
    "product_name": "Lithops (Patience)"
  },
  "resource": {
    "url": "https://underground.substratesymposium.com/buy/lithops",
    "mimeType": "",
    "description": "Lithops (Patience) — Study of extremely slow development for cultivating patience with gradual progress."
  },
  "extensions": {
    "bazaar": {
      "info": {
        "input": {
          "type": "http",
          "method": "GET",
          "queryParams": {}
        },
        "output": {
          "type": "json",
          "example": {
            "title": "Lithops (Patience)",
            "content": "Study of extremely slow development for cultivating patience with gradual progress.",
            "product": "lithops",
            "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/lithops\")",
    "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/lithops"
  },
  "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": "Lithops (Patience)",
          "content": "Study of extremely slow development for cultivating patience with gradual progress.",
          "product": "lithops",
          "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