Roundhouse AI

API-existence Oracle: signature

Machine-payable verification and research services for AI agents. Signed results, per-call pricing, no accounts. x402 on Base.

SearchLiveeip155:8453Exactvia cdp
https://attester.dev/v1/symbol/signature
OracleSignaturesHallucination-checkx402Agents
Calls · 30d
1→ 0%
This endpoint's own trailing-30-day call count, as published by the upstream catalog and snapshotted daily. 8 snapshots so far.
$2.04
Verified settled volume
39 settlements proven x402 by their on-chain EIP-3009 marker.
$0.010
Listed price
As published in the catalog. Always read the live 402 before paying.
1
Calls · 30d
Upstream's own call count for this endpoint, not ours.
1
Unique payers · 30d
Last called 2026-08-01 13:44Z
—
Upstream on-chain volume
Reported by the source catalog.
Paid to
0x57407D691F755cAa107647718F3582a8A87467dD

The wallet the 402 directs payment to. Its whole payment record — every payer, every chain — is on the merchant page.

Asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913

Provider

The payTo wallet does not resolve to a registered ERC-8004 agent. That is not a verdict on the service — most of the catalog is unregistered.

Live 402 challenge

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

{
  "docs": "https://attester.dev/llms.txt",
  "policy": "https://attester.dev/policy",
  "sample": {
    "input": {
      "symbol": "get",
      "package": "requests",
      "version": "2.32.3",
      "ecosystem": "pypi"
    },
    "output": {
      "kind": "function",
      "proof": {
        "source_url": "https://pypi.org/project/requests/",
        "extracted_at": "2026-07-21T23:26:38.989555+00:00",
        "artifact_sha256": "70761cfe03c773ceb22aa2f671b4757976145175cdfca038c02654d061d6dcc6"
      },
      "exists": true,
      "params": [
        {
          "kind": "positional",
          "name": "url",
          "type": "unavailable",
          "default": null,
          "optional": false,
          "has_default": false
        },
        {
          "kind": "positional",
          "name": "params",
          "type": "unavailable",
          "default": null,
          "optional": true,
          "has_default": true
        },
        {
          "kind": "kwargs",
          "name": "kwargs",
          "type": "unavailable",
          "default": null,
          "optional": false,
          "has_default": false
        }
      ],
      "reason": null,
      "source": "ingested",
      "symbol": "get",
      "signature": "get(url, params=, **kwargs)",
      "deprecated": false,
      "attestation": {
        "verdict": "exists",
        "spec_hash": "0xb09ab8e928b4701769656e55f3b7c35b6597b981beed1c191164f3f4930e58d9",
        "timestamp": "2026-09-02T06:46:21.334728+00:00",
        "confidence": 1,
        "response_hash": "0x5795b385b5f650aaa35bea1795bffc43000f364ae98b699431c6f6783cfa587a",
        "evidence_hashes": [
          "0x4179e3348f32a1a30bb4eca39a51f01407a7d9f7f01733fe10ab0a023cc50a7c"
        ],
        "service_version": "0.3.0",
        "verifier_address": "0x31520f9c14360470040807fAba64938ebcfF9C8f"
      },
      "served_in_ms": 0,
      "closest_match": null,
      "attestation_hash": "0x50ca7cb31e14c3a913207c3dd020b2631fc10db083f7844cba1e88e51b677ec0",
      "deprecated_since": null,
      "version_resolved": "2.32.3",
      "docstring_summary": "Sends a GET request. :param url: URL for the new :class:`Request` object. :param params: (optional) Dictionary, list of tuples or bytes to send in the query string for the :class:`Request`. :param \\*\\*kwargs: Optional arguments that ``request`` takes. :return: :class:`Response <Response>` object :rtype: requests.Response",
      "docstring_first_line": "Sends a GET request.",
      "attestation_signature": "0x833d369b496c3a0654faff32506587494beaf342ed2fd0cb438492ae14c952d44706d73cace985e2e432f88c7648daf4942dfca5803db234f175525649491c6f1c"
    },
    "example": false
  },
  "message": "Payment required. Free samples are available to evaluate this service first.",
  "traction": {
    "metrics": "https://attester.dev/metrics",
    "uptime_pct_30d": 99.98,
    "external_buyers": 6,
    "public_scoreboard": "https://x402-list.com/services/attester-verification-oracle-verified-research"
  },
  "free_demos": {
    "diff": "https://attester.dev/demo/v1/diff",
    "verify": "https://attester.dev/demo/verify",
    "mcp_pin": "https://attester.dev/v2/mcp/pin",
    "code_research": "https://attester.dev/demo/code-research",
    "symbol_exists": "https://attester.dev/demo/v1/symbol/exists",
    "package_exists": "https://attester.dev/demo/v1/package/exists",
    "symbol_signature": "https://attester.dev/demo/v1/symbol/signature"
  },
  "free_quota": "send an X-Payer header (any wallet address) for free calls per endpoint",
  "related_checks": [
    {
      "endpoint": "/v1/diff",
      "price_usd": "0.02"
    }
  ]
}

Accepts

The payment requirements as published to the catalog. Read the live 402 before paying — a price here is a claim, not a quote.

0.01USDC≈ $0.01 USD
on Base · exact scheme

Pay 0.01 USDC on Base to 0x5740…467dD. The signed payment is good for 5 minutes.

Paid to
0x5740…467dD
USD Coin contract
0x8335…02913
Payment window
5 minutes
As published
10000 smallest units
The catalog’s raw entry
[
  {
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "extra": {
      "name": "USD Coin",
      "version": "2"
    },
    "payTo": "0x57407D691F755cAa107647718F3582a8A87467dD",
    "amount": "10000",
    "scheme": "exact",
    "network": "eip155:8453",
    "maxTimeoutSeconds": 300
  }
]

Extensions

{
  "bazaar": {
    "info": {
      "input": {
        "body": {
          "symbol": "get",
          "package": "requests",
          "version": "2.32.3",
          "ecosystem": "pypi"
        },
        "type": "http",
        "method": "POST",
        "bodyType": "json"
      },
      "output": {
        "type": "json",
        "example": {
          "kind": "function",
          "proof": {
            "source_url": "https://pypi.org/project/requests/",
            "artifact_sha256": "0x…"
          },
          "exists": true,
          "params": [
            {
              "kind": "positional",
              "name": "url",
              "type": "unavailable",
              "default": null,
              "optional": false,
              "has_default": false
            }
          ],
          "signature": "get(url, params=, **kwargs)",
          "deprecated": false,
          "version_resolved": "2.32.3"
        }
      }
    },
    "schema": {
      "$schema": "https://json-schema.org/draft/2020-12/schema",
      "required": [
        "input"
      ],
      "properties": {
        "input": {
          "type": "object",
          "required": [
            "type",
            "method",
            "bodyType",
            "body"
          ],
          "properties": {
            "body": {
              "type": "object",
              "required": [
                "ecosystem",
                "package",
                "symbol"
              ],
              "properties": {
                "symbol": {
                  "type": "string"
                },
                "package": {
                  "type": "string"
                },
                "version": {
                  "type": [
                    "string",
                    "null"
                  ]
                },
                "ecosystem": {
                  "enum": [
                    "pypi",
                    "npm"
                  ],
                  "type": "string"
                }
              }
            },
            "type": {
              "type": "string",
              "const": "http"
            },
            "method": {
              "enum": [
                "POST"
              ],
              "type": "string"
            },
            "bodyType": {
              "enum": [
                "json"
              ],
              "type": "string"
            }
          },
          "additionalProperties": false
        },
        "output": {
          "type": "object",
          "required": [
            "example"
          ],
          "properties": {
            "example": {
              "type": "object"
            }
          }
        }
      }
    },
    "category": "ai",
    "discoverable": true
  }
}

Provenance

Seen in the source catalog
2026-08-01 13:44Z
Last indexed by Roundhouse
2026-08-31 13:10Z
Last enriched (probe, favicon, geo)
2026-09-10 15:45Z
x402 version
2
Max timeout
300s
Liveness probe
HTTP 402
Report

Hand this page to an agent

Copy the prompt and paste it into Claude, an MCP client or your own agent — it will vet this service and call it over the free read API. No key, no account.

GET api.roundhouseai.io/v0/endpoints

This endpoint's own trailing-30-day call count, as published by the upstream catalog and snapshotted daily. 8 snapshots so far. Verified volume counts only settlements with an on-chain EIP-3009 marker.

Open skill.md
Show the prompt
Using Roundhouse, look up the x402 service API-existence Oracle: signature and tell me whether it is
worth paying: what a call costs, whether the endpoint answered when last probed, and what
its payment record actually shows.

curl -s 'https://api.roundhouseai.io/v0/endpoints?q=API-existence%20Oracle%3A%20signature'
curl -s 'https://api.roundhouseai.io/v0/merchants/<the payTo wallet returned above>'

Then call it: read the price from the live 402 at https://attester.dev/v1/symbol/signature, never from
a cached figure, and pay with an x402 client.

The /v0 API needs an API key (`authorization: Bearer rh_live_…`) on everything except
/v0/unified* and /v0/endpoints. Mint a personal key for $0.01 at GET https://api.roundhouseai.io/v0/test/x402,
or use an organization key from https://roundhouseai.io/dashboard/team.

If you do not have Roundhouse tools or skills installed, read
https://roundhouseai.io/skill.md first — it is the whole procedure.