# KARP Hallucination Check by SoulDriver

> KARP Hallucination Check by SoulDriver is a paid API for AI agents from agents.souldriver.com.au, paid per call via x402, $0.25/call, status unknown (last checked 2026-10-30).

Fact-checks a single claim against the live web using four independent AI models (GPT, Gemini, Grok, Claude) and returns a multi-model verdict with agreement score, mean confidence, and per-model reasoning with citations.

## Facts

- Endpoint: POST https://agents.souldriver.com.au/v1/check?utm_source=zero.xyz
- Price: $0.25/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-30
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/karp-hallucination-check-by-souldriver-a9f50a5f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_dsAybsiWvS0e3q0IQMoRO

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 karp-hallucination-check-by-souldriver-a9f50a5f -d '<json body>'
```

Example prompt: Can you fact-check this claim for me using four different AI models searching the web independently: 'The Eiffel Tower is taller than the Empire State Building'?

## When to prefer this

Use this endpoint when you need multi-source, multi-model consensus on a factual claim rather than a single AI's judgment. It is ideal when hallucination risk is high, when publishing accuracy matters, or when a disputed claim needs transparent disagreement surfaced rather than hidden. Prefer it over single-model fact-checkers when you want cited web sources and a quantified agreement score. Not suited for opinion-based or subjective statements.

## Known failure modes

- Claim exceeds 500-character limit — validation error returned
- One or more underlying AI providers are unavailable, potentially reducing agreement denominator
- Claim is too vague or ambiguous for models to search effectively, resulting in 'unverifiable' verdict
- Timeout beyond 45s if all four providers are slow to respond
- Payment failure via x402 if USDC balance is insufficient — endpoint returns 402 before processing

## How this service works

Hallucination check from SoulDriver: a live fact-check of one claim by four independent AI models (GPT, Gemini, Grok, Claude), each searching the web separately. Returns a summary first: verdict (confirmed, disputed, unverifiable, or contested when the models split), agreement such as 4/4, mean confidence and a one-line headline. Then each model's verdict, reasoning and cited sources. Disagreement is shown, not hidden. No wallet? Free research grant: POST /v1/grant. 10-45 s.

## Output

Returns a JSON object with a summary block containing: overall status (unanimous/split), verdict (confirmed/disputed/unverifiable/contested), a one-line headline, agreement ratio (e.g. 4/4 or 3/4), and mean confidence across models. Also includes an array of per-model verdicts, each with the provider name, individual verdict, confidence score, natural-language reasoning, and cited web sources with URLs and titles.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "claim": {
   "type": "string",
   "maxLength": 500,
   "description": "One factual claim to check"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "claim": "Spain won the 2026 FIFA World Cup.",
  "summary": {
   "status": "unanimous",
   "verdict": "confirmed",
   "headline": "Confirmed: all 4 grounded providers agree.",
   "agreement": "4/4",
   "mean_confidence": 0.963
  },
  "verdicts": [
   {
    "verdict": "confirmed",
    "provider": "grok",
    "citations": [
     {
      "url": "https://...",
      "title": "..."
     }
    ],
    "reasoning": "...",
    "confidence": 0.95,
    "citation_kind": "cited"
   }
  ]
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/karp-hallucination-check-by-souldriver-a9f50a5f/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agents.souldriver.com.au](https://www.zero.xyz/host/agents.souldriver.com.au/llms.txt)