Agent Output Verifier

Live 402 challenge

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

{
  "error": "No payment was attached to the request.",
  "accepts": [
    {
      "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
      "extra": {
        "name": "USD Coin",
        "version": "2"
      },
      "payTo": "0x42a3c399f83BCcC3b9eEf81e65954a715D54855E",
      "amount": "20000",
      "scheme": "exact",
      "network": "eip155:8453",
      "maxTimeoutSeconds": 300
    },
    {
      "asset": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
      "extra": {
        "feePayer": "GVJJ7rdGiXr5xaYbRwRbjfaJL7fmwRygFi1H6aGqDveb"
      },
      "payTo": "38Fmaf3MWTR6AWPWrtrdXoqn6iqfVcUBHMFRhiUAEjFb",
      "amount": "20000",
      "scheme": "exact",
      "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
      "maxTimeoutSeconds": 300
    }
  ],
  "guidance": {
    "docs": {
      "openapi": "https://verify.sarnai.dev/openapi.json",
      "llms_txt": "https://verify.sarnai.dev/llms.txt"
    },
    "price": "$0.02 USDC per call (POST /verify/schema and /verify/deliverable); GET /score/{agent_id} is $0.01 USDC",
    "how_to_pay": "Send the request with no payment: the 402 answer lists the price and networks (USDC on Base or Solana) in the PAYMENT-REQUIRED header (x402 v2). Sign it with an x402 client and resend the same request with the PAYMENT-SIGNATURE header. The MCP tool at https://verify.sarnai.dev/mcp takes the same arguments.",
    "what_to_do": "Pay with x402 v2 as described in how_to_pay, or send a valid request while the free allowance lasts. Nothing was charged by this response.",
    "free_allowance": {
      "message": "Free during launch: 1000 verification checks a day per caller through MCP and REST (POST /verify/schema and POST /verify/deliverable), then $0.02 USDC per call via x402.",
      "available": true,
      "resets_at": "2026-10-16T00:00:00+00:00",
      "applies_to": "valid requests to POST /verify/schema and POST /verify/deliverable and the MCP tool verify_schema; one count per client address",
      "remaining_calls_today": 996,
      "calls_per_client_per_day": 1000
    },
    "example_request": {
      "url": "https://verify.sarnai.dev/verify/deliverable",
      "body": {
        "task_id": "example-task-1",
        "expected_schema": {
          "type": "object",
          "required": [
            "total"
          ],
          "properties": {
            "total": {
              "type": "number"
            }
          }
        },
        "submitted_output": {
          "total": 42
        }
      },
      "method": "POST",
      "headers": {
        "Content-Type": "application/json"
      }
    }
  },
  "resource": {
    "url": "https://verify.sarnai.dev/verify/deliverable",
    "tags": [
      "deliverable",
      "agent-output",
      "verification",
      "json-schema",
      "x402"
    ],
    "mimeType": "application/json",
    "description": "Free during launch: check AI agent output before you accept or pay for a deliverable against your JSON Schema and rules. Pass/fail, % of checks passed, fix hints, signed attestation and receipt. $0.02 USDC after, x402 v2.",
    "serviceName": "Agent Output Verifier"
  },
  "free_trial": {
    "url": "https://verify.sarnai.dev/mcp",
    "via": "mcp+rest",
    "tool": "verify_schema",
    "client": "identified by request IP address; the same address's REST and MCP verification calls share one allowance",
    "launch": true,
    "message": "Free during launch. 996 of 1000 free checks remain today for this client, shared by this REST endpoint and the MCP tool 'verify_schema' at https://verify.sarnai.dev/mcp. This request needs payment because the request body is not a valid verification request.",
    "available": true,
    "resets_at": "2026-10-16T00:00:00+00:00",
    "rest_free": true,
    "transport": "streamable-http",
    "declined_because": "invalid_request",
    "remaining_calls_today": 996,
    "calls_per_client_per_day": 1000
  },
  "probe_note": {
    "path": "/verify/deliverable",
    "method": "POST",
    "message": "The real call is POST /verify/deliverable with the output to check as a JSON body; this GET/HEAD answer is the payment challenge for it. A valid POST is served free while the launch allowance lasts, then paid.",
    "example_body": {
      "task_id": "example-task-1",
      "expected_schema": {
        "type": "object",
        "required": [
          "total"
        ],
        "properties": {
          "total": {
            "type": "number"
          }
        }
      },
      "submitted_output": {
        "total": 42
      }
    }
  },
  "x402Version": 2,
  "payment_error": {
    "charged": false,
    "message": "This call requires payment; none was attached.",
    "retryable": true,
    "error_code": "no_payment",
    "retry_after": null,
    "next_actions": [
      {
        "action": "submit_x402_v2_payment"
      }
    ],
    "payment_terms": {
      "accepts": [
        {
          "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
          "extra": {
            "name": "USD Coin",
            "version": "2"
          },
          "payTo": "0x42a3c399f83BCcC3b9eEf81e65954a715D54855E",
          "amount": "20000",
          "scheme": "exact",
          "network": "eip155:8453",
          "maxTimeoutSeconds": 300
        },
        {
          "asset": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
          "extra": {
            "feePayer": "GVJJ7rdGiXr5xaYbRwRbjfaJL7fmwRygFi1H6aGqDveb"
          },
          "payTo": "38Fmaf3MWTR6AWPWrtrdXoqn6iqfVcUBHMFRhiUAEjFb",
          "amount": "20000",
          "scheme": "exact",
          "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
          "maxTimeoutSeconds": 300
        }
      ],
      "resource": {
        "url": "https://verify.sarnai.dev/verify/deliverable",
        "tags": [
          "deliverable",
          "agent-output",
          "verification",
          "json-schema",
          "x402"
        ],
        "mimeType": "application/json",
        "description": "Free during launch: check AI agent output before you accept or pay for a deliverable against your JSON Schema and rules. Pass/fail, % of checks passed, fix hints, signed attestation and receipt. $0.02 USDC after, x402 v2.",
        "serviceName": "Agent Output Verifier"
      }
    }
  }
}

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": "0x42a3c399f83BCcC3b9eEf81e65954a715D54855E",
    "amount": "20000",
    "scheme": "exact",
    "network": "eip155:8453",
    "maxTimeoutSeconds": 300
  },
  {
    "asset": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
    "extra": {
      "feePayer": "GVJJ7rdGiXr5xaYbRwRbjfaJL7fmwRygFi1H6aGqDveb"
    },
    "payTo": "38Fmaf3MWTR6AWPWrtrdXoqn6iqfVcUBHMFRhiUAEjFb",
    "amount": "20000",
    "scheme": "exact",
    "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
    "maxTimeoutSeconds": 300
  }
]

Extensions

{
  "bazaar": {
    "info": {
      "input": {
        "body": {
          "rules": [
            {
              "type": "unique",
              "field": "findings[].id"
            }
          ],
          "task_id": "example-task-002",
          "agent_id": "example-agent-001",
          "enforce_rules": true,
          "expected_schema": {
            "type": "object",
            "required": [
              "report_title",
              "findings"
            ],
            "properties": {
              "findings": {
                "type": "array",
                "items": {
                  "type": "object",
                  "required": [
                    "id",
                    "summary"
                  ],
                  "properties": {
                    "id": {
                      "type": "string"
                    },
                    "summary": {
                      "type": "string",
                      "minLength": 1
                    }
                  }
                },
                "minItems": 1
              },
              "report_title": {
                "type": "string",
                "minLength": 1
              }
            }
          },
          "submitted_output": {
            "findings": [
              {
                "id": "F-1",
                "summary": "Vendor A raised its entry plan by 10%."
              },
              {
                "id": "F-2",
                "summary": "Vendor B added a free tier."
              }
            ],
            "report_title": "Q3 competitor pricing scan"
          }
        },
        "type": "http",
        "method": "POST",
        "bodyType": "json"
      },
      "output": {
        "type": "json",
        "example": {
          "flags": [],
          "hints": [],
          "errors": [],
          "result": "pass",
          "verify": {
            "mcp": "https://verify.sarnai.dev/mcp",
            "service": "Agent Output Verifier",
            "key_version": "v1-2026-09c",
            "hash_algorithm": "SHA-256",
            "public_key_url": "https://verify.sarnai.dev/.well-known/agent-card.json",
            "canonicalization": "RFC 8785 (JCS)"
          },
          "overall": {
            "ratio": 1,
            "total": 28,
            "passed": 28
          },
          "summary": {
            "result": "pass",
            "blocking_checks": []
          },
          "task_id": "example-task-002",
          "agent_id": "example-agent-001",
          "rules_hash": "a888b42989834a385f47403af04349f49bb47c950918ed100dc1df20d9d30a3b",
          "attestation": {
            "algorithm": "Ed25519",
            "signature": "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA==",
            "timestamp": "2026-01-01T00:00:00+00:00",
            "key_version": "v1-example"
          },
          "flags_total": 0,
          "hints_total": 0,
          "output_hash": "dc7786e4a55de9423a7b14297944b00ebe8e5c709f2063a78230aa2df7004b50",
          "schema_hash": "55cdc036dc420c8ed2f46ea0a6f2df6f99821be1b9b388d5267736066d66579b",
          "verified_at": "2026-01-01T00:00:00+00:00",
          "errors_total": 0,
          "next_actions": [
            {
              "for": "seller",
              "action": "attach_receipt"
            },
            {
              "for": "buyer",
              "action": "proceed_to_payment"
            }
          ],
          "request_hash": "0defdf7d0e73e14d785a03658d6f2b3ef6e210569516387e2cc1d057ed6ba6b0",
          "enforce_rules": true,
          "errors_detail": [],
          "flags_omitted": 0,
          "hints_omitted": 0,
          "errors_omitted": 0,
          "verification_id": "0b8f2a6e-5d1c-4f43-9a07-3c61d9e2b8a4",
          "integrity_checks": {
            "ratio": 1,
            "total": 12,
            "passed": 12
          },
          "verifier_version": "0.4.1",
          "schema_compliance": {
            "ratio": 1,
            "total": 16,
            "passed": 16
          },
          "errors_detail_total": 0,
          "strict_content_check": false,
          "errors_detail_omitted": 0
        }
      }
    },
    "schema": {
      "type": "object",
      "$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": [
                "task_id",
                "expected_schema",
                "submitted_output"
              ],
              "properties": {
                "rules": {
                  "type": [
                    "array",
                    "null"
                  ],
                  "items": {
                    "type": "object",
                    "required": [
                      "type",
                      "field"
                    ],
                    "properties": {
                      "type": {
                        "type": "string"
                      },
                      "field": {
                        "type": "string"
                      },
                      "value": {
                        "type": [
                          "integer",
                          "number",
                          "string",
                          "null"
                        ]
                      },
                      "equals": {
                        "type": [
                          "integer",
                          "number",
                          "null"
                        ]
                      },
                      "values": {
                        "type": [
                          "array",
                          "null"
                        ]
                      },
                      "in_field": {
                        "type": [
                          "string",
                          "null"
                        ]
                      },
                      "tolerance": {
                        "type": "number"
                      },
                      "if_present": {
                        "type": "boolean"
                      },
                      "other_field": {
                        "type": [
                          "string",
                          "null"
                        ]
                      },
                      "equals_field": {
                        "type": [
                          "string",
                          "null"
                        ]
                      }
                    }
                  },
                  "description": "Optional cross-field rules: sum_equals, gte, lte, exists_in, unique (duplicate detection). Violations are reported as informational flags unless enforce_rules is true."
                },
                "bounds": {
                  "type": [
                    "object",
                    "null"
                  ],
                  "description": "Optional per-field min/max, keyed by dotted path with '[]' array wildcard (e.g. 'items[].price'). Numbers or ISO-8601 dates. Violations are reported as informational flags unless enforce_rules is true."
                },
                "detail": {
                  "enum": [
                    "full",
                    "compact"
                  ],
                  "type": "string",
                  "description": "'full' (default) returns everything; 'compact' returns only the summary, next actions, receipt and signature. Use compact inside verify-repair loops to save tokens. 'compact' fields: summary, next_actions, result, the receipt fields (verification_id, task_id, agent_id, output_hash, schema_hash, rules_hash, verified_at, verifier_version, enforce_rules, strict_content_check), verify and attestation - errors, errors_de…"
                },
                "task_id": {
                  "type": "string",
                  "description": "Your own identifier for this verification. 1-200 printable characters, no control characters and no lone Unicode surrogate; a request outside that range is rejected (422), not truncated."
                },
                "agent_id": {
                  "type": [
                    "string",
                    "null"
                  ],
                  "description": "Optional label identifying the AI agent that produced submitted_output (for example, the seller), used for /reputation and the trust score: records and scores belong to the producer, not to whoever calls this endpoint. It is an unauthenticated label. agent_ids starting with 'test-' are reserved for testing: the verification runs normally but is never recorded, so it cannot affect any reputation or trust score. 1-200…"
                },
                "enforce_rules": {
                  "type": "boolean",
                  "description": "Opt-in. When true, every configured bound and consistency rule must hold, or the result is 'fail' (like strict_content_check), with an 'enforce_rules: ...' entry in errors. That includes a rule or bound that cannot run (its path is missing, a value is not comparable, a value has nothing to be compared against): it fails rather than passing silently, so omitting a field, in the whole path or in any array element the…"
                },
                "expected_schema": {
                  "type": "object",
                  "description": "Required. The JSON Schema (draft-04 to 2020-12) that submitted_output must satisfy: your own requirements, as a JSON object."
                },
                "submitted_output": {
                  "description": "Required. The output being checked: any JSON value (object, array, string, number, boolean or null), exactly as the AI agent produced it."
                },
                "strict_content_check": {
                  "type": "boolean",
                  "description": "Opt-in. When true, any string in submitted_output containing control characters (e.g. null bytes) or embedded HTML/script markup makes the result 'fail'. When false (default) this is not checked at all."
                }
              }
            },
            "type": {
              "type": "string",
              "const": "http"
            },
            "method": {
              "enum": [
                "POST",
                "PUT",
                "PATCH"
              ],
              "type": "string"
            },
            "bodyType": {
              "enum": [
                "json",
                "form-data",
                "text"
              ],
              "type": "string"
            }
          },
          "additionalProperties": false
        },
        "output": {
          "type": "object",
          "required": [
            "type"
          ],
          "properties": {
            "type": {
              "type": "string"
            },
            "example": {
              "type": "object",
              "required": [
                "summary",
                "next_actions",
                "result",
                "verification_id",
                "task_id",
                "agent_id",
                "output_hash",
                "schema_hash",
                "rules_hash",
                "request_hash",
                "verified_at",
                "verifier_version",
                "enforce_rules",
                "strict_content_check",
                "errors",
                "errors_total",
                "errors_omitted",
                "errors_detail_total",
                "errors_detail_omitted",
                "flags_total",
                "flags_omitted",
                "hints",
                "hints_total",
                "hints_omitted",
                "schema_compliance",
                "integrity_checks",
                "overall",
                "verify",
                "attestation"
              ],
              "properties": {
                "flags": {
                  "type": "array",
                  "items": {
                    "type": "object",
                    "required": [
                      "check",
                      "field",
                      "detail"
                    ],
                    "properties": {
                      "check": {
                        "type": "string"
                      },
                      "field": {
                        "type": "string"
                      },
                      "detail": {
                        "type": "string"
                      },
                      "severity": {
                        "type": "string"
                      }
                    }
                  },
                  "description": "Integrity findings (placeholder text, possible truncation, bounds and consistency-rule violations)"
                },
                "hints": {
                  "type": "array",
                  "items": {
                    "type": "object",
                    "required": [
                      "source",
                      "check",
                      "path",
                      "expected",
                      "found"
                    ],
                    "properties": {
                      "path": {
                        "type": "string"
                      },
                      "check": {
                        "type": "string"
                      },
                      "found": {
                        "type": "string"
                      },
                      "source": {
                        "type": "string"
                      },
                      "expected": {
                        "type": "string"
                      }
                    }
                  },
                  "description": "Machine-actionable, template-based fix hints: one per schema validation failure (first, in the same order as…"
                },
                "errors": {
                  "type": "array",
                  "items": {
                    "type": "string"
                  },
                  "description": "Every violation (schema, then strict-content, then enforce_rules), capped at the first 100 schema-validation…"
                },
                "result": {
                  "enum": [
                    "pass",
                    "fail"
                  ],
                  "type": "string"
                },
                "verify": {
                  "type": "object",
                  "description": "How to verify this attestation and receipt without any other lookup than this response and public_key_url: ca…"
                },
                "overall": {
                  "type": "object",
                  "description": "A pooled count across both groups: (schema_compliance.passed + integrity_checks.passed) / (schema_compliance.…"
                },
                "summary": {
                  "type": "object",
                  "description": "Compact digest of the verdict: the same `result`, and `blocking_checks` (the distinct check codes that caused…"
                },
                "task_id": {
                  "type": "string"
                },
                "agent_id": {
                  "type": [
                    "string",
                    "null"
                  ],
                  "description": "Echo of the agent_id label supplied in the request; null if none"
                },
                "rules_hash": {
                  "type": [
                    "string",
                    "null"
                  ],
                  "description": "SHA-256 (64 lowercase hex chars) of the RFC 8785 (JCS) canonical JSON of {\"bounds\": <the bounds you supplied…"
                },
                "attestation": {
                  "type": "object",
                  "description": "Ed25519 signature over this response (every field above, including the receipt fields) plus the timestamp and…"
                },
                "flags_total": {
                  "type": "integer",
                  "description": "How many flags exist in total (flags holds at most the first 100, plus a flags_truncated marker when there ar…"
                },
                "hints_total": {
                  "type": "integer",
                  "description": "How many hints exist in total (hints holds at most the first 20)"
                },
                "output_hash": {
                  "type": [
                    "string",
                    "null"
                  ],
                  "description": "SHA-256 (64 lowercase hex chars = 32 bytes; add 0x to use it as a bytes32) of the JCS canonical JSON of submi…"
                },
                "schema_hash": {
                  "type": [
                    "string",
                    "null"
                  ],
                  "description": "SHA-256 (64 lowercase hex chars) of the JCS canonical JSON of expected_schema"
                },
                "verified_at": {
                  "type": "string",
                  "description": "ISO-8601 UTC time this service ran the verification"
                },
                "errors_total": {
                  "type": "integer",
                  "description": "How many errors exist in total"
                },
                "next_actions": {
                  "type": "array",
                  "items": {
                    "type": "object"
                  },
                  "description": "What to do next, machine-readable"
                },
                "request_hash": {
                  "type": [
                    "string",
                    "null"
                  ],
                  "description": "SHA-256 (64 lowercase hex chars, no 0x prefix) of the RFC 8785 (JCS) canonical JSON of the request as parsed:…"
                },
                "enforce_rules": {
                  "type": "boolean",
                  "description": "Whether the request had enforce_rules on: true means every rule and bound had to hold (violations and unrunna…"
                },
                "errors_detail": {
                  "type": "array",
                  "items": {
                    "type": "object",
                    "required": [
                      "check",
                      "path",
                      "expected",
                      "found",
                      "message"
                    ],
                    "properties": {
                      "path": {
                        "type": "string"
                      },
                      "check": {
                        "type": "string"
                      },
                      "found": {
                        "type": "string"
                      },
                      "message": {
                        "type": "string"
                      },
                      "expected": {
                        "type": "string"
                      }
                    }
                  },
                  "description": "The structured form of the leading entries in `errors`, same order, so a caller can act (check, path, expecte…"
                },
                "flags_omitted": {
                  "type": "integer",
                  "description": "Integrity flags beyond the 100 returned; 0 when nothing was cut off"
                },
                "hints_omitted": {
                  "type": "integer",
                  "description": "hints_total minus len(hints)"
                },
                "errors_omitted": {
                  "type": "integer",
                  "description": "errors_total minus len(errors); 0 when nothing was cut off"
                },
                "verification_id": {
                  "type": "string",
                  "description": "Unique UUID (v4) for this verification"
                },
                "integrity_checks": {
                  "type": "object",
                  "description": "Integrity checks that passed out of those evaluated (per string: placeholder and truncation, plus strict cont…"
                },
                "verifier_version": {
                  "type": "string"
                },
                "schema_compliance": {
                  "type": "object",
                  "description": "JSON Schema assertions that passed out of those evaluated (each keyword such as type/required/minimum, at eac…"
                },
                "errors_detail_total": {
                  "type": "integer",
                  "description": "How many entries in `errors` have a structured form available"
                },
                "strict_content_check": {
                  "type": "boolean",
                  "description": "Whether the request had strict_content_check on: true means control characters and embedded HTML/script marku…"
                },
                "errors_detail_omitted": {
                  "type": "integer",
                  "description": "errors_total minus errors_detail_total; 0 when every error has a structured form"
                }
              }
            }
          }
        }
      }
    }
  }
}

Provenance

Seen in the source catalog

2026-10-15 01:14Z

Last indexed by Roundhouse

2026-10-26 22:40Z

Last enriched (probe, favicon, geo)

2026-10-15 07:15Z

x402 version

2

Max timeout

300s

Liveness probe

HTTP 402