# Verification Oracle

> Verification Oracle is a paid API for AI agents from attester.dev, paid per call via x402, $0.15/call, status unknown (last checked 2026-09-14).

Verifies or attests claims, facts, or content via an oracle-style POST endpoint with per-call payment.

## Facts

- Endpoint: POST https://attester.dev/verify
- Price: $0.15/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/verification-oracle-293a2fb2
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_k183xM9RWupAqRDLo6wr7

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability verification-oracle-293a2fb2 -d '<json body>'
```

Example prompt: Can you verify this claim for me using the Verification Oracle: 'Company X was founded in 2010 and is headquartered in San Francisco'? I need an attestation result I can trust.

## When to prefer this

Use this endpoint when you need an authoritative, oracle-style verification or attestation of a claim, fact, or piece of content — especially when trust, auditability, or a paid verification signal adds credibility. Prefer over free validators when the verification needs to be defensible or carries a cost-based trust signal.

## Known failure modes

- Invalid or malformed claim input returns an error
- Payment not included or insufficient (x402 payment required at $0.25 USDC) results in 402 response
- Ambiguous or unverifiable claim may return low-confidence or inconclusive result
- Network or service downtime results in 5xx error

## How this service works

Verification Oracle: independent checks on another agent's work (citation support, data/schema validation) returning a wallet-signed attestation. $0.15 USDC per verification.

## Output

The agent receives a verification or attestation result indicating whether the submitted claim or content is valid, including a judgment or confidence signal from the oracle.

## Request schema (JSON Schema)

```json
{
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "properties": {
  "input": {
   "type": "object",
   "additionalProperties": false,
   "properties": {
    "body": {
     "type": "object",
     "properties": {
      "job": {
       "type": "object",
       "description": "Verification job: citation support check, data/schema validation",
       "properties": {
        "type": {
         "enum": [
          "citation",
          "code",
          "data"
         ],
         "type": "string"
        },
        "claim": {
         "type": "string"
        },
        "sources": {
         "type": "array",
         "items": {
          "type": "string"
         }
        }
       },
       "required": [
        "type"
       ]
      }
     },
     "required": [
      "job"
     ]
    },
    "bodyType": {
     "enum": [
      "json"
     ],
     "type": "string"
    },
    "method": {
     "enum": [
      "POST"
     ],
     "type": "string"
    },
    "type": {
     "const": "http",
     "type": "string"
    }
   },
   "required": [
    "type",
    "method",
    "bodyType",
    "body"
   ]
  },
  "output": {
   "type": "object",
   "properties": {
    "example": {
     "type": "object"
    }
   },
   "required": [
    "example"
   ]
  }
 },
 "required": [
  "input"
 ]
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/verification-oracle-293a2fb2/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from attester.dev](https://www.zero.xyz/host/attester.dev/llms.txt)