Open Source Filings

Live 402 challenge

Captured by the enrichment pass, not read just now. Prices can change — always read the 402 the endpoint answers with.

{
  "note": "x402 v2 clients: the canonical quote is the PAYMENT-REQUIRED response header (base64 JSON envelope). This body is a v1 compatibility rendering of the same quote.",
  "error": "Payment required",
  "accepts": [
    {
      "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
      "extra": {
        "name": "USD Coin",
        "version": "2"
      },
      "payTo": "0x72f62dE8b70d6CFa8Cc2dF6f21F243f289F3396c",
      "scheme": "exact",
      "network": "base",
      "mimeType": "application/json",
      "resource": "https://api.osf-master-server.com/x402/models/search/:query",
      "description": "Search AI and machine learning models on the Hugging Face Hub by name, author or organization, task, library, or license. Returns model id, author, task pipeline, library, declared license, download and like counts, tags and a provenance URL per match. For model selection, license screening, dependency review, and tracking which models an organization publishes.",
      "maxAmountRequired": "50000",
      "maxTimeoutSeconds": 300
    }
  ],
  "x402Version": 1,
  "free_alternative": {
    "how": "This exact search is free over MCP. Point any MCP client at https://api.osf-master-server.com/mcp and call the tool search_ai_models with {\"query\": \"<your query>\"}. It runs the identical search code as this paid route and needs no payment, no signup, no API key and no wallet.",
    "limit": "no daily cap",
    "price": "$0.00",
    "full_catalog": "https://api.osf-master-server.com/x402/discovery/resources",
    "free_mcp_tool": "search_ai_models",
    "paid_route_adds": "the same answer over plain HTTP, for agents that cannot speak MCP",
    "free_mcp_endpoint": "https://api.osf-master-server.com/mcp",
    "not_an_x402_field": "free_alternative is an OSF addition to the 402 body, not part of the x402 specification, which defines no field for advertising a free alternative. x402 SDKs silently drop unknown keys, so read this from the raw JSON response rather than expecting your client library to surface it."
  }
}

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": "0x72f62dE8b70d6CFa8Cc2dF6f21F243f289F3396c",
    "amount": "50000",
    "scheme": "exact",
    "network": "eip155:8453",
    "maxTimeoutSeconds": 300
  }
]

Extensions

{
  "bazaar": {
    "info": {
      "input": {
        "type": "http",
        "method": "GET",
        "pathParams": {
          "query": ":query"
        },
        "queryParams": {
          "format": "json"
        }
      },
      "output": {
        "type": "json",
        "example": {
          "result": "MATCHES_FOUND",
          "matches": [
            {
              "task": "image-segmentation",
              "title": "nvidia/segformer-b5-finetuned-cityscapes-1024-1024",
              "author": "nvidia",
              "source": "HUGGINGFACE",
              "downloads": 128429,
              "record_id": 12345
            }
          ],
          "match_count": 1,
          "search_evidence": {
            "scan": {
              "matches_omitted": 25,
              "candidates_examined": 35,
              "candidate_set_complete": true
            },
            "_about": "Proof of work, on EVERY result including NO_MATCH: the terms actually searched, how many records were in scope per source, how fresh they are, whether the scan completed or was truncated, and on an empty result the per-term record counts plus a known-good control query re-measured live in the same request. Numbers shown are illustrative.",
            "corpus": {
              "records_in_scope": 1558599,
              "newest_record_ingested_utc": "2026-08-01T15:47:55Z"
            },
            "result_confidence": "matches_found"
          }
        }
      }
    },
    "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",
                "HEAD",
                "DELETE"
              ],
              "type": "string"
            },
            "pathParams": {
              "type": "object",
              "required": [
                "query"
              ],
              "properties": {
                "query": {
                  "type": "string",
                  "description": "Keyword(s): model name, author or org, task, library, or license. E.g. 'image segmentation' or 'nvidia'."
                }
              }
            },
            "queryParams": {
              "type": "object",
              "properties": {}
            }
          },
          "additionalProperties": false
        },
        "output": {
          "type": "object",
          "required": [
            "type"
          ],
          "properties": {
            "type": {
              "type": "string"
            },
            "example": {
              "type": "object"
            }
          }
        }
      }
    },
    "routeTemplate": "/x402/models/search/:query"
  }
}

Provenance

Seen in the source catalog

2026-08-24 06:23Z

Last indexed by Roundhouse

2026-09-23 05:50Z

Last enriched (probe, favicon, geo)

2026-09-11 11:16Z

x402 version

2

Max timeout

300s

Liveness probe

HTTP 0