# Netzhandwerker Claim Checker

> Netzhandwerker Claim Checker is a paid API for AI agents from tools.netzhandwerker.de, paid per call via x402, $0.008/call, status unknown (last checked 2026-09-16).

Checks a textual claim against up to 8 source URLs and returns evidence quotes, verdict, and confidence score

## Facts

- Endpoint: POST https://tools.netzhandwerker.de/v1/claim/check
- Price: $0.008/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-16
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/netzhandwerker-claim-checker-b9af0f76
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_wdN5H8T_TIIEqXrTkgp5A

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 netzhandwerker-claim-checker-b9af0f76 -d '<json body>'
```

Example prompt: Can you check whether the claim 'The World Bank expects global growth of 2.7 percent in 2026' is actually supported by these two sources: https://www.worldbank.org/en/publication/global-economic-prospects and https://www.imf.org/en/Publications/WEO?

## When to prefer this

Use this endpoint when you need to check whether a specific factual claim is actually stated in one or more known source URLs, rather than searching the open web. Ideal for fact-checking pipelines, journalism tools, or research workflows where you already have candidate sources and want to verify if they support a claim — especially for numerical claims or quotes where exact matching matters.

## Known failure modes

- Source URL unreachable or returns non-200 status — source marked as not reachable with no evidence extracted
- Claim contains no recognizable key terms — low confidence or empty evidence array
- Source URL content is not in a parseable text format (e.g. PDF, binary) — no sentences scanned
- Claim exceeds 600 character limit — request rejected
- More than 8 source URLs provided — request rejected
- Source page has no text matching claim terms — verdict may be 'nicht_belegt' with zero evidence

## How this service works

x402-Werkzeuge für autonome Agenten.

## Output

Returns a JSON object with a verdict ('in_quelle_belegt' or similar), an array of evidence quotes with direction (supporting or contradicting), confidence score (0-1), matched terms, count of supporting vs contradicting evidence, and per-source metadata including reachability, HTTP status, character count, and sentences scanned.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "claim": {
   "type": "string",
   "maxLength": 600,
   "description": "Die zu pruefende Behauptung"
  },
  "sources": {
   "type": "array",
   "items": {
    "type": "string"
   },
   "maxItems": 8,
   "description": "Bis zu acht Quell-URLs"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "note": "Belegsuche in den genannten Quellen, keine Bewertung des Wahrheitsgehalts.",
  "claim": "Die Weltbank erwartet fuer 2026 ein globales Wachstum von 2,7 Prozent.",
  "sources": [
   {
    "url": "https://www.worldbank.org/en/publication/global-economic-prospects",
    "title": "Global Economic Prospects",
    "status": 200,
    "matches": 2,
    "reachable": true,
    "text_chars": 48219,
    "content_type": "text/html",
    "sentences_scanned": 312
   }
  ],
  "verdict": "in_quelle_belegt",
  "evidence": [
   {
    "quote": "Global growth is projected to hold at 2.7 percent in 2026 as trade and investment recover slowly.",
    "direction": "stuetzt",
    "source_url": "https://www.worldbank.org/en/publication/global-economic-prospects",
    "source_title": "Global Economic Prospects",
    "matched_terms": [
     "wachstum",
     "2026"
    ],
    "term_coverage": 0.67,
    "matched_numbers": [
     "2026"
    ]
   }
  ],
  "key_terms": [
   "weltbank",
   "erwartet",
   "globales",
   "wachstum",
   "2,7",
   "prozent"
  ],
  "confidence": 0.8,
  "supporting": 2,
  "contradicting": 0,
  "evidence_count": 2,
  "numbers_in_claim": [
   "2026",
   "2,7 Prozent"
  ],
  "numbers_not_found": []
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/netzhandwerker-claim-checker-b9af0f76/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from tools.netzhandwerker.de](https://www.zero.xyz/host/tools.netzhandwerker.de/llms.txt)