# VerityLayer Quick Verify

> VerityLayer Quick Verify is a paid API for AI agents from api.veritylayer.dev, paid per call via x402, $0.02/call, status unknown (last checked 2026-09-14).

Verifies whether an AI-generated claim or citation is factually supported or hallucinated, returning a verdict, evidence sources, reasoning, and confidence score.

## Facts

- Endpoint: POST https://api.veritylayer.dev/verify/quick
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/veritylayer-quick-verify-52c614b7
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_JwlF1LbnNGN_Cs0L-XrN9

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 veritylayer-quick-verify-52c614b7 -d '<json body>'
```

Example prompt: Before you send that AI-written summary to the client, run it through VerityLayer to check whether the claims and citations are actually real — I need to know the verdict, any supporting evidence, and how confident it is.

## When to prefer this

Choose VerityLayer when you need a lightweight, fast, per-claim hallucination check with a clear supported/refuted verdict and cited evidence — especially when your AI pipeline is generating citations, legal references, or factual assertions that must be trustworthy before reaching end users. It is particularly strong at catching fabricated citations (8/8 on the Mata v. Avianca benchmark) and operates fail-closed, meaning it errs toward flagging rather than passing suspect content.

## Known failure modes

- Claim is too vague or ambiguous to verify — may return low confidence or inconclusive verdict
- Source material unavailable or behind paywalls — evidence array may be sparse
- Extremely niche or newly emerging facts may lack sufficient indexed sources for verification
- Malformed or empty input claim returns validation error
- Network timeout or service unavailability returns HTTP 5xx

## How this service works

Fact-check a claim before your agent acts on, repeats, or ships it — verify a claim, is this true, catch hallucinations. Independent, fail-closed verification for AI agents: a verdict with calibrated 0-1 confidence, reasoning, and web-sourced evidence; abstains rather than guess, never fabricates. Every verdict ships a signed, independently re-verifiable receipt — proof of what was asked and answered, free to verify forever. Tier: quick — fast ungrounded pre-filter (Haiku).

## Output

A JSON object containing: 'verdict' (e.g. 'supported' or 'refuted'), 'evidence' (array of authoritative source citations backing the verdict), 'reasoning' (human-readable explanation of why the claim is supported or not), and 'confidence' (a 0–1 score indicating how certain the engine is).

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "claim": {
   "type": "string"
  },
  "context": {
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "verdict": "supported",
  "evidence": [
   "Encyclopaedia Britannica — Eiffel Tower, Paris, France."
  ],
  "reasoning": "Multiple authoritative sources place the Eiffel Tower on the Champ de Mars in Paris, France.",
  "confidence": 0.97
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/veritylayer-quick-verify-52c614b7/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.veritylayer.dev](https://www.zero.xyz/host/api.veritylayer.dev/llms.txt)