# SAVER Verifier

> SAVER Verifier is a paid API for AI agents from agent-production-9804.up.railway.app, paid per call via x402, $0.2/call, status unknown (last checked 2026-10-20).

Verifies factual claims by searching the web and returning supporting or refuting evidence with a confidence score

## Facts

- Endpoint: POST https://agent-production-9804.up.railway.app/verify?utm_source=zero.xyz
- Price: $0.2/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-20
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/saver-verifier-d82804a1
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_roE47E6sQSEV4deQHN60k

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 saver-verifier-d82804a1 -d '<json body>'
```

Example prompt: Can you fact-check this claim for me: 'The global average temperature has risen by 1.2 degrees Celsius since pre-industrial times'? Use additional context that this is from a climate report published in 2023.

## When to prefer this

Choose SAVER Verifier when you need structured, evidence-backed fact-checking with a confidence score and source citations — particularly for AI-generated content, news claims, or marketing statements that need validation before publication. It is well-suited for single claim verification where both a verdict and supporting evidence are required, rather than bulk document analysis or pure plagiarism checking.

## Known failure modes

- Claim is too vague or ambiguous for web search to resolve
- No credible sources found for niche or highly specific claims
- Conflicting evidence leads to uncertain or low-confidence result
- Claim involves very recent events not yet indexed by search
- Rate limiting or service unavailability returns a non-200 response
- Payment not received leads to 402 Payment Required error

## How this service works

Paid verification layer for autonomous AI agents. Verify claims before decisions using web evidence and source-backed analysis

## Output

A JSON object containing: a 'status' field indicating whether the claim is 'supported', 'refuted', or 'uncertain'; an 'evidence' array of relevant authoritative sources or quotes; a 'confidence' score between 0 and 1 indicating certainty of the verdict; and an 'explanation' summarizing how the evidence relates to the claim.

## Request schema (JSON Schema)

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

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "status": "supported",
  "evidence": [
   "Relevant authoritative sources support the claim."
  ],
  "confidence": 0.98,
  "explanation": "The available evidence supports the claim."
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/saver-verifier-d82804a1/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agent-production-9804.up.railway.app](https://www.zero.xyz/host/agent-production-9804.up.railway.app/llms.txt)