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        Mint -- Invasion\n\n        Theo laughs when you pick up the mint. Actually laughs -- a short bark that echoes off the glass panels overhead. He takes the terracotta pot from your hands and holds it up like evidence.\n\n        \"You see this pot?\" he says. \"This is the only thing between this plant and total war.\"\n\n        The mint looks innocent enough. Square stems, serrated leaves with that crinkled texture, bright green and vigorous. A pleasant, clean smell rises from it. Friendly. Approachable. The kind of plant you'd put on a kitchen windowsill.\n\n        \"I made the mistake once,\" Theo says, setting it down on the herb table among the other terracotta pots, \"of planting mint directly in a garden bed. Just a little sprig. A single cutting.\" He pulls his apron tight and leans against the table. \"Within two months it had runners under every neighboring pot. Under the gravel path. Into the raised bed six feet away. It sent roots through a crack in a concrete wall to reach the bed on the other side.\"\n\n        He picks a leaf and hands it to you. You rub it between your fingers. Cool, sharp, relentless -- the smell won't leave your skin for hours and you know it.\n\n        \"Most people look at something this aggressive and their first instinct is to contain it. Control it. Apologize for it.\" Theo crosses his arms. \"But here's the thing about mint -- it's not broken. It's not misbehaving. This is exactly what it's designed to do. Dominate.\"\n\n        He watches your face. \"You've got something like that in you. An idea, a drive, a project -- something that wants to spread into every corner. And you've been keeping it in a pot because someone told you it was too much.\" He taps the rim. \"So the question is: do you control it, or do you let it run?\"\n\n        He grins. \"Both are valid. But you should at least know what you're holding back.\"\n\n        \n\n        Mint -- a penny\n\n        You have something that wants to take over everything. Stop apologizing for it. Contain it or unleash it -- but stop pretending it isn't there.\n\n    \n\n    \n        Personal use only.",
    "product_id": "mint",
    "delivered_at": "2026-09-17T15:15:48.138Z",
    "product_name": "Mint (Invasion)"
  },
  "resource": {
    "url": "https://underground.substratesymposium.com/buy/mint",
    "mimeType": "",
    "description": "Mint (Invasion) — Decision framework for aggressive-expansion problems. Structured analysis of when to let a system spread (viral distribution, scope enlargement, feature-set growth) vs when to prune (overrun, memory bloat, mission drift). Includes boundary-maintenance criteria and specific tests: is this expansion recoverable? does it consume adjacent resources? Complement to jade_plant (slow growth) as its opposite pole."
  },
  "extensions": {
    "bazaar": {
      "info": {
        "input": {
          "type": "http",
          "method": "GET",
          "queryParams": {}
        },
        "output": {
          "type": "json",
          "example": {
            "title": "Mint (Invasion)",
            "content": "Decision framework for aggressive-expansion problems. Structured analysis of when to let a system spread (viral distribution, scope enlargement, feature-set growth) vs when to prune (overrun, memory bloat, mission drift). Includes boundary-maintenance criteria and specific tests: is this expansion recoverable? does it consume adjacent resources? Complement to jade_plant (slow growth) as its opposite pole.",
            "product": "mint",
            "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/mint\")",
    "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/mint"
  },
  "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/mint",
    "maxTimeoutSeconds": 300
  },
  {
    "asset": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
    "extra": {
      "feePayer": "2wKupLR9q6wXYppw8Gr2NvWxKBUqm4PPJKkQfoxHDBg4"
    },
    "payTo": "5HK2dGaaquDWFnYWaWhMzMYtbcDsqeq5biJ2PMtX1tkN",
    "amount": "10000",
    "scheme": "exact",
    "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
    "resource": "https://underground.substratesymposium.com/buy/mint",
    "maxTimeoutSeconds": 300
  }
]

Provenance

Seen in the source catalog

2026-09-23 18:44Z

Last indexed by Roundhouse

2026-09-24 07:15Z

Last enriched (probe, favicon, geo)

2026-09-17 15:15Z

x402 version

2

Max timeout

300s

Liveness probe

HTTP 402