# Claim Grounding Deep Research

> Claim Grounding Deep Research is a paid API for AI agents from claim-grounding.prospectintel.workers.dev, paid per call via x402, $8/call, status unknown (last checked 2026-10-17).

Checks factual claims in text against Wikipedia, Wikidata, Google News, Europe PMC, FRED, and SEC EDGAR and returns a verdict on each claim's accuracy

## Facts

- Endpoint: POST https://claim-grounding.prospectintel.workers.dev/v1/deep_research?utm_source=zero.xyz
- Price: $8/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-17
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/claim-grounding-deep-research-1b779a07
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_2G02atxcOnSbO6fHg6iCc

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 claim-grounding-deep-research-1b779a07 -d '<json body>'
```

Example prompt: Can you fact-check this paragraph from my report — 'The Federal Reserve raised interest rates seven times in 2022, and mRNA vaccines have been shown to reduce severe COVID-19 outcomes by over 90%' — and tell me whether each claim is supported, contradicted, or something else?

## When to prefer this

Choose this endpoint when an AI agent needs to verify factual accuracy of specific claims against authoritative sources including Wikipedia, academic literature (PubMed), financial data (FRED), and SEC filings — especially when fine-grained verdicts (supported/contradicted/outdated/mixed/insufficient_evidence) are needed. Prefer this over generic web search when you need a structured, per-claim verdict rather than raw search results. Ideal for auditing LLM outputs, validating research summaries, or grounding agent-generated answers before they are shown to end users. The $8/call pricing makes it best suited for high-stakes fact checks rather than high-volume trivial lookups.

## Known failure modes

- 400 error if confirmed:true is not included in the request body — nothing is charged
- Insufficient evidence verdict when sources don't cover the claim's subject
- Outdated verdict for time-sensitive claims where sources have newer information
- Mixed verdict when sources disagree on the claim
- Long polling delay if the job queue is busy — client must poll the job URL returned in response
- Claims about very niche topics may return insufficient_evidence due to limited source coverage

## How this service works

Pay-per-call claim checks for AI agents. Sources: Wikipedia, Wikidata, Google News, Europe PMC (PubMed), FRED and SEC EDGAR. USDC on Base via x402 (Coinbase CDP facilitator). No API key. Every checked claim returns verdict: supported | contradicted | outdated | mixed | insufficient_evidence, plus status_detail and legacy_verdict (pre-1.2.0 value: supported | contradicted | not_found | conflict).

## Output

Returns a job receipt with a job_id and poll URL for async retrieval. Each claim in the input gets a claim_id, a verdict from the set (supported, contradicted, outdated, mixed, insufficient_evidence), a status_detail explanation, and a legacy_verdict for backward compatibility. The receipt also includes creation timestamp and the price charged in USD.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "text": {
   "type": "string"
  },
  "claim": {
   "type": "object",
   "properties": {
    "text": {
     "type": "string"
    }
   }
  },
  "answer": {
   "type": "string",
   "description": "Text whose claims should be researched."
  },
  "claim_ids": {
   "type": "array",
   "items": {
    "type": "string"
   }
  },
  "confirmed": {
   "const": true,
   "description": "Required. Without confirmed: true the call returns 400 and nothing is charged."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "mode": "fast",
  "poll": "GET /v1/jobs/job_8c1d2e3f4a5b6c7d (free)",
  "claims": [],
  "job_id": "job_8c1d2e3f4a5b6c7d",
  "status": "queued",
  "receipt": {
   "claims": [
    {
     "text": "Paris is the capital of France",
     "claim_id": "clm_3f9a1c2b4d5e6f70",
     "grounding_required": true
    }
   ],
   "job_id": "job_8c1d2e3f4a5b6c7d",
   "created_at": "2026-10-10T12:00:00.000Z",
   "priced_usd": 8
  },
  "next_actions": []
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/claim-grounding-deep-research-1b779a07/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from claim-grounding.prospectintel.workers.dev](https://www.zero.xyz/host/claim-grounding.prospectintel.workers.dev/llms.txt)