# Second Opinion Claim Verifier

> Second Opinion Claim Verifier is a paid API for AI agents from second-opinion-production.up.railway.app, paid per call via x402, $0.2/call, status unknown (last checked 2026-09-15).

Submits a claim to an adversarial AI agent that attempts to refute it via live web research and returns a structured verdict with citations

## Facts

- Endpoint: POST https://second-opinion-production.up.railway.app/v1/verify
- Price: $0.2/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/second-opinion-claim-verifier-7b8b2dde
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_mZGhqybh62_6C5DStEoW4

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 second-opinion-claim-verifier-7b8b2dde -d '<json body>'
```

Example prompt: Can you run a second opinion check on this claim: 'The Great Wall of China is visible from space with the naked eye' — I want an adversarial agent to try to refute it with live web research and give me a structured verdict with citations.

## When to prefer this

Use this endpoint when you need independent adversarial verification of a specific factual claim backed by live web citations, especially when you want to stress-test an assertion rather than simply search for supporting evidence. Prefer this over generic search when you need a structured verdict with a deliberate attempt to find contradicting evidence.

## Known failure modes

- Claim is too vague to research — returns ambiguous or inconclusive verdict
- Web research yields no relevant sources — citations may be sparse
- Rate limiting or upstream LLM failure — returns 5xx error
- Malformed request body missing required fields — returns 400 validation error
- Payment not processed or x402 payment header missing/invalid — returns 402 Payment Required

## How this service works

Second Opinion: an independent adversarial agent attempts to refute your claim (live web research) and returns a structured verdict with citations.

## Output

A structured verdict object indicating whether the claim was refuted or supported, along with citations from live web research and a reasoned adversarial analysis

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "bodyType",
    "body",
    "method"
   ],
   "properties": {
    "body": {
     "properties": {}
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/second-opinion-claim-verifier-7b8b2dde/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from second-opinion-production.up.railway.app](https://www.zero.xyz/host/second-opinion-production.up.railway.app/llms.txt)