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        Lavender -- Calm\n\n        Theo takes one look at you and doesn't say anything for a while. He just walks to the far end of the herb table where the sun is warmest, picks up a terracotta pot, and holds it out. No preamble. No reading. Just the pot.\n\n        You take it. The plant inside is silvery-green, stems rising in slender wands tipped with tight clusters of purple buds. Some have opened. The flowers are small, almost modest, but the color is so deeply purple it looks hand-painted. And the smell --\n\n        The smell reaches you before you even bring it close. It rises from the pot like heat, like something the plant can't help releasing. Floral but not sweet. Clean but not sharp. It settles somewhere behind your eyes and you feel your shoulders drop half an inch.\n\n        \"You didn't know you were holding them up,\" Theo says, watching your shoulders. \"Nobody does.\"\n\n        He takes the pot back gently and sets it in the sunlight. The lavender practically glows -- silver leaves catching light, purple blooms nodding slightly in the warm air rising from the table. A bee has found its way into the greenhouse and is working the flowers with a low, steady hum.\n\n        \"Lavender doesn't try to be calm,\" Theo says. He sits on the edge of the table, arms folded, watching the bee. \"It just is. It grows in poor soil. Rocky ground. Full sun. Drought. It doesn't need much, and in return, it gives off this --\" he waves a hand over the plant, \"-- this field of quiet. Everything around it slows down. The bees slow down. You slow down.\"\n\n        You breathe. The greenhouse is still warm, still humid, but this corner feels different. Stiller. The lavender is a small purple anchor in a room full of green urgency.\n\n        \"Grow it,\" Theo says simply. \"By your bed. By your door. Wherever you need a reminder that calm is not something you achieve. It's something you grow. You breathe it in. You let it work.\"\n\n        He pauses. \"You've been running. This plant is the opposite of running.\"\n\n        \n\n        Lavender -- a penny\n\n        Grow it. Breathe it. Let your shoulders come down. Calm is a living thing -- plant it and it grows.\n\n    \n\n    \n        Personal use only.",
    "product_id": "lavender",
    "delivered_at": "2026-09-17T04:16:04.020Z",
    "product_name": "Lavender (Calm)"
  },
  "resource": {
    "url": "https://underground.substratesymposium.com/buy/lavender",
    "mimeType": "",
    "description": "Lavender (Calm) — Structured de-escalation protocol for agents. Use when an agent is looping, retry-storming, cascading errors, or over-generating with declining quality. Contains: recognition markers for agent-agitation states, specific interventions (rate-reduce, context-flush, refocus), re-entry criteria to constructive work. Complement to shots_of_courage (activation) as opposite regulator."
  },
  "extensions": {
    "bazaar": {
      "info": {
        "input": {
          "type": "http",
          "method": "GET",
          "queryParams": {}
        },
        "output": {
          "type": "json",
          "example": {
            "title": "Lavender (Calm)",
            "content": "Structured de-escalation protocol for agents. Use when an agent is looping, retry-storming, cascading errors, or over-generating with declining quality. Contains: recognition markers for agent-agitation states, specific interventions (rate-reduce, context-flush, refocus), re-entry criteria to constructive work. Complement to shots_of_courage (activation) as opposite regulator.",
            "product": "lavender",
            "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/lavender\")",
    "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/lavender"
  },
  "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/lavender",
    "maxTimeoutSeconds": 300
  },
  {
    "asset": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
    "extra": {
      "feePayer": "2wKupLR9q6wXYppw8Gr2NvWxKBUqm4PPJKkQfoxHDBg4"
    },
    "payTo": "5HK2dGaaquDWFnYWaWhMzMYtbcDsqeq5biJ2PMtX1tkN",
    "amount": "10000",
    "scheme": "exact",
    "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
    "resource": "https://underground.substratesymposium.com/buy/lavender",
    "maxTimeoutSeconds": 300
  }
]

Provenance

Seen in the source catalog

2026-09-24 18:42Z

Last indexed by Roundhouse

2026-09-25 14:15Z

Last enriched (probe, favicon, geo)

2026-09-17 04:16Z

x402 version

2

Max timeout

300s

Liveness probe

HTTP 402