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": "10000",
      "scheme": "exact",
      "network": "eip155:8453",
      "maxTimeoutSeconds": 300
    },
    {
      "asset": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
      "extra": {
        "feePayer": "GVJJ7rdGiXr5xaYbRwRbjfaJL7fmwRygFi1H6aGqDveb"
      },
      "payTo": "38Fmaf3MWTR6AWPWrtrdXoqn6iqfVcUBHMFRhiUAEjFb",
      "amount": "10000",
      "scheme": "exact",
      "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
      "maxTimeoutSeconds": 300
    }
  ],
  "guidance": {
    "docs": {
      "openapi": "https://score.sarnai.dev/openapi.json",
      "llms_txt": "https://score.sarnai.dev/llms.txt"
    },
    "price": "$0.01 USDC per lookup when there is a score (an agent_id with no history, or a reserved test- id, is answered free)",
    "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.",
    "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://score.sarnai.dev/score/example-agent-001",
      "method": "GET"
    },
    "free_alternative": "GET https://score.sarnai.dev/reputation/{agent_id} is free (pass/fail counts, no score)."
  },
  "resource": {
    "url": "https://score.sarnai.dev/score/:agent_id",
    "tags": [
      "trust-score",
      "reputation",
      "agent-reputation",
      "ai-agents",
      "verification-history"
    ],
    "mimeType": "application/json",
    "description": "Check an AI agent's track record: signed verification history, pass/fail counts, recency-weighted score. $0.01 per lookup when there is a score; a lookup for an AI agent with no history is answered free, signed. USDC via x402 v2 (Base/Solana).",
    "serviceName": "Agent Output Verifier"
  },
  "free_trial": {
    "code": "paid_only",
    "price": "$0.01",
    "message": "Agent Scores are paid only: $0.01 per lookup.",
    "available": false
  },
  "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": "10000",
          "scheme": "exact",
          "network": "eip155:8453",
          "maxTimeoutSeconds": 300
        },
        {
          "asset": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
          "extra": {
            "feePayer": "GVJJ7rdGiXr5xaYbRwRbjfaJL7fmwRygFi1H6aGqDveb"
          },
          "payTo": "38Fmaf3MWTR6AWPWrtrdXoqn6iqfVcUBHMFRhiUAEjFb",
          "amount": "10000",
          "scheme": "exact",
          "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
          "maxTimeoutSeconds": 300
        }
      ],
      "resource": {
        "url": "https://score.sarnai.dev/score/:agent_id",
        "tags": [
          "trust-score",
          "reputation",
          "agent-reputation",
          "ai-agents",
          "verification-history"
        ],
        "mimeType": "application/json",
        "description": "Check an AI agent's track record: signed verification history, pass/fail counts, recency-weighted score. $0.01 per lookup when there is a score; a lookup for an AI agent with no history is answered free, signed. USDC via x402 v2 (Base/Solana).",
        "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": "10000",
    "scheme": "exact",
    "network": "eip155:8453",
    "maxTimeoutSeconds": 300
  },
  {
    "asset": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
    "extra": {
      "feePayer": "BENrLoUbndxoNMUS5JXApGMtNykLjFXXixMtpDwDR9SP"
    },
    "payTo": "38Fmaf3MWTR6AWPWrtrdXoqn6iqfVcUBHMFRhiUAEjFb",
    "amount": "10000",
    "scheme": "exact",
    "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
    "maxTimeoutSeconds": 300
  }
]

Extensions

{
  "bazaar": {
    "info": {
      "input": {
        "type": "http",
        "method": "GET",
        "pathParams": {
          "agent_id": ":agent_id"
        }
      },
      "output": {
        "type": "json",
        "example": {
          "basis": "recency_weighted_pass_rate",
          "reason": null,
          "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)"
          },
          "factors": [
            {
              "name": "recency_weighted_pass_rate",
              "value": 0.83,
              "parameters": {
                "half_life_days": 30
              },
              "sample_size": 1847,
              "effective_sample_size": 612.4,
              "confidence_interval_95": [
                0.81,
                0.85
              ]
            }
          ],
          "agent_id": "example-agent",
          "last_seen": "2025-12-31T23:41:07+00:00",
          "attestation": {
            "algorithm": "Ed25519",
            "signature": "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA==",
            "timestamp": "2026-01-01T00:00:00+00:00",
            "key_version": "v1-example"
          },
          "computed_at": "2026-01-01T00:00:00+00:00",
          "sample_size": 1847,
          "trust_score": 0.83,
          "failed_count": 314,
          "passed_count": 1533,
          "verified_count": 1847,
          "identity_verified": false,
          "confidence_interval_95": [
            0.81,
            0.85
          ]
        }
      }
    },
    "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": [
                "agent_id"
              ],
              "properties": {
                "agent_id": {
                  "type": "string",
                  "maxLength": 200,
                  "minLength": 1,
                  "description": "The agent_id to score."
                }
              }
            },
            "queryParams": {
              "type": "object",
              "properties": {}
            }
          },
          "additionalProperties": false
        },
        "output": {
          "type": "object",
          "required": [
            "type"
          ],
          "properties": {
            "type": {
              "type": "string"
            },
            "example": {
              "type": "object",
              "title": "TrustScoreResponse",
              "required": [
                "agent_id",
                "identity_verified",
                "trust_score",
                "sample_size",
                "confidence_interval_95",
                "basis",
                "reason",
                "factors",
                "verified_count",
                "passed_count",
                "failed_count",
                "last_seen",
                "computed_at",
                "verify",
                "attestation"
              ],
              "properties": {
                "basis": {
                  "type": "string",
                  "title": "Basis",
                  "description": "Names the formula behind trust_score. Its meaning never changes under the same name; a different formula gets a different basis."
                },
                "reason": {
                  "anyOf": [
                    {
                      "type": "string"
                    },
                    {
                      "type": "null"
                    }
                  ],
                  "title": "Reason",
                  "description": "null when scored. 'no_data': no verification history at all. 'insufficient_recent_data': history exists but has decayed to under 0.05 effective observations."
                },
                "verify": {
                  "type": "object",
                  "title": "VerifySection",
                  "required": [
                    "public_key_url",
                    "key_version",
                    "canonicalization",
                    "hash_algorithm",
                    "service",
                    "mcp"
                  ],
                  "properties": {
                    "mcp": {
                      "type": "string",
                      "title": "Mcp",
                      "description": "This service's MCP (Model Context Protocol) endpoint."
                    },
                    "service": {
                      "type": "string",
                      "title": "Service",
                      "description": "This service's name."
                    },
                    "key_version": {
                      "type": "string",
                      "title": "Key Version",
                      "description": "Matches attestation.key_version."
                    },
                    "hash_algorithm": {
                      "type": "string",
                      "title": "Hash Algorithm",
                      "description": "Algorithm behind every *_hash field in this response."
                    },
                    "public_key_url": {
                      "type": "string",
                      "title": "Public Key Url",
                      "description": "Agent-card URL listing the public key for key_version below, and every key this service has ever signed with."
                    },
                    "canonicalization": {
                      "type": "string",
                      "title": "Canonicalization",
                      "description": "How every hash below, and the signed bytes themselves, are computed."
                    }
                  },
                  "description": "How to verify this attestation and receipt without any other lookup than this response and public_key_url: canonicalization and hash algorithm, this service's name, and its MCP endpoint."
                },
                "factors": {
                  "type": "array",
                  "items": {
                    "type": "object",
                    "title": "ScoreFactor",
                    "required": [
                      "name",
                      "value",
                      "confidence_interval_95",
                      "sample_size",
                      "effective_sample_size",
                      "parameters"
                    ],
                    "properties": {
                      "name": {
                        "type": "string",
                        "title": "Name",
                        "description": "Stable identifier of this factor."
                      },
                      "value": {
                        "anyOf": [
                          {
                            "type": "number"
                          },
                          {
                            "type": "null"
                          }
                        ],
                        "title": "Value",
                        "description": "Factor value in [0, 1]; null when it cannot be computed (see the response's `reason`)."
                      },
                      "parameters": {
                        "type": "object",
                        "title": "Parameters",
                        "description": "Parameters in force, so the value can be reproduced.",
                        "additionalProperties": {
                          "anyOf": [
                            {
                              "type": "number"
                            },
                            {
                              "type": "integer"
                            },
                            {
                              "type": "string"
                            }
                          ]
                        }
                      },
                      "sample_size": {
                        "type": "integer",
                        "title": "Sample Size",
                        "description": "Raw number of verification calls behind this factor, all history."
                      },
                      "effective_sample_size": {
                        "type": "number",
                        "title": "Effective Sample Size",
                        "description": "Sum of the recency weights: how many 'recent-equivalent' observations the history is worth. This, not sample_size, is what the interval is computed from."
                      },
                      "confidence_interval_95": {
                        "anyOf": [
                          {
                            "type": "array",
                            "items": {
                              "type": "number"
                            },
                            "maxItems": 2,
                            "minItems": 2
                          },
                          {
                            "type": "null"
                          }
                        ],
                        "title": "Confidence Interval 95",
                        "description": "[lower, upper] 95% Wilson score interval; null when value is null."
                      }
                    },
                    "description": "One input to the score. v1 has exactly one; later versions add entries here."
                  },
                  "title": "Factors",
                  "description": "The inputs behind trust_score. v1 has one entry; consumers should ignore entries they don't recognize, so factors can be added without breaking them."
                },
                "agent_id": {
                  "type": "string",
                  "title": "Agent Id",
                  "description": "Identifies the AI agent that produced the output checked by the /verify/schema calls this score is built from (for example, the seller): this record belongs to that producer."
                },
                "last_seen": {
                  "anyOf": [
                    {
                      "type": "string"
                    },
                    {
                      "type": "null"
                    }
                  ],
                  "title": "Last Seen",
                  "description": "ISO-8601 UTC time of the most recent verification on record; null when there is none. Like agent_id itself, this reflects calls made under this label by anyone."
                },
                "attestation": {
                  "type": "object",
                  "title": "Attestation",
                  "required": [
                    "algorithm",
                    "key_version",
                    "timestamp",
                    "signature"
                  ],
                  "properties": {
                    "algorithm": {
                      "type": "string",
                      "const": "Ed25519",
                      "title": "Algorithm"
                    },
                    "signature": {
                      "type": "string",
                      "title": "Signature"
                    },
                    "timestamp": {
                      "type": "string",
                      "title": "Timestamp"
                    },
                    "key_version": {
                      "type": "string",
                      "title": "Key Version"
                    }
                  },
                  "description": "Ed25519 signature over this response (every field above) with the same key as /verify/schema, under the context 'json-schema-verifier/trust-score-attestation/v1'. Verification steps: /.well-known/agent-card.json."
                },
                "computed_at": {
                  "type": "string",
                  "title": "Computed At",
                  "description": "ISO-8601 UTC time the score was computed; ages are measured from here."
                },
                "sample_size": {
                  "type": "integer",
                  "title": "Sample Size",
                  "description": "Total verification calls on record for this agent_id."
                },
                "trust_score": {
                  "anyOf": [
                    {
                      "type": "number"
                    },
                    {
                      "type": "null"
                    }
                  ],
                  "title": "Trust Score",
                  "description": "Recency-weighted pass rate as a raw float in [0.0, 1.0]; null when there is nothing meaningful to report (see `reason`). A statistical summary of structural verification history, not a measure of overall trustworthiness and not a prediction of future behavior."
                },
                "failed_count": {
                  "type": "integer",
                  "title": "Failed Count",
                  "description": "How many of those calls returned result 'fail'."
                },
                "passed_count": {
                  "type": "integer",
                  "title": "Passed Count",
                  "description": "How many of those calls returned result 'pass'."
                },
                "verified_count": {
                  "type": "integer",
                  "title": "Verified Count",
                  "description": "Raw number of /verify/schema calls on record for this agent_id (all history, no recency weighting). Equals sample_size."
                },
                "identity_verified": {
                  "type": "boolean",
                  "title": "Identity Verified",
                  "description": "Whether agent_id is bound to a proven identity. Currently always false: agent_id is an unauthenticated label chosen by whoever called /verify/schema, so this history may include calls made by anyone under that id, and the score says nothing about who the AI agent really is. It flips to true only if and when identity is actually authenticated."
                },
                "confidence_interval_95": {
                  "anyOf": [
                    {
                      "type": "array",
                      "items": {
                        "type": "number"
                      },
                      "maxItems": 2,
                      "minItems": 2
                    },
                    {
                      "type": "null"
                    }
                  ],
                  "title": "Confidence Interval 95",
                  "description": "[lower, upper] 95% Wilson score interval around trust_score, computed from the effective (recency-discounted) sample size. Wide = little recent evidence."
                }
              }
            }
          }
        }
      }
    },
    "routeTemplate": "/score/:agent_id"
  }
}

Provenance

Seen in the source catalog

2026-10-25 11:18Z

Last indexed by Roundhouse

2026-10-26 17:20Z

Last enriched (probe, favicon, geo)

2026-10-15 07:15Z

x402 version

2

Max timeout

300s

Liveness probe

HTTP 402