Full text and open-access PDF retrieval for a paper

[
  {
    "scheme": "exact",
    "network": "eip155:8453",
    "payTo": "0x4df66B6c140778fe0717880A7c6dDE5Ea53AcDeA",
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "amount": "40000",
    "maxTimeoutSeconds": 300
  }
]

{
  "bazaar": {
    "info": {
      "input": {
        "method": "GET",
        "queryParams": {
          "id": "1706.03762"
        },
        "type": "http"
      },
      "output": {
        "example": {
          "count": 1,
          "items": [
            {
              "arxivId": "1706.03762",
              "fulltextSource": "ar5iv",
              "openAccess": true,
              "sections": [
                {
                  "heading": "1 Introduction",
                  "text": "Recurrent neural networks, long short-term memory..."
                }
              ],
              "sourceUrl": "https://ar5iv.labs.arxiv.org/html/1706.03762",
              "text": "1 Introduction\nRecurrent neural networks...",
              "type": "paper_fulltext"
            }
          ]
        },
        "type": "json"
      }
    },
    "schema": {
      "$schema": "https://json-schema.org/draft/2020-12/schema",
      "properties": {
        "input": {
          "additionalProperties": false,
          "properties": {
            "method": {
              "enum": [
                "GET",
                "HEAD",
                "DELETE"
              ],
              "type": "string"
            },
            "queryParams": {
              "anyOf": [
                {
                  "required": [
                    "id"
                  ]
                },
                {
                  "required": [
                    "doi"
                  ]
                }
              ],
              "properties": {
                "doi": {
                  "description": "alias for id (DOI form)",
                  "type": "string"
                },
                "id": {
                  "description": "arXiv id, DOI, OpenAlex id, PMID, or PMCID",
                  "type": "string"
                }
              },
              "required": [],
              "type": "object"
            },
            "type": {
              "const": "http",
              "type": "string"
            }
          },
          "required": [
            "type",
            "method"
          ],
          "type": "object"
        },
        "output": {
          "properties": {
            "example": {
              "type": "object"
            },
            "type": {
              "type": "string"
            }
          },
          "required": [
            "type"
          ],
          "type": "object"
        }
      },
      "required": [
        "input"
      ],
      "type": "object"
    }
  }
}

curl "https://api.kadec0.xyz/v1/paper-fulltext"
# -> 402 Payment Required, accepts[] lists how to pay
# retry with a PAYMENT-SIGNATURE (or PAYMENT header) once paid

const res = await fetch("https://api.kadec0.xyz/v1/paper-fulltext");
if (res.status === 402) {
  const { accepts } = await res.json();
  // pay one of accepts[] via an x402 client, then retry with the payment header
}

import httpx
res = httpx.get("https://api.kadec0.xyz/v1/paper-fulltext")
if res.status_code == 402:
    accepts = res.json()["accepts"]
    # pay one of accepts[] via an x402 client, then retry with the payment header