# Bob Fact-Checker (assimilatethis.com)

> Bob Fact-Checker (assimilatethis.com) is a paid API for AI agents from bob.assimilatethis.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-10).

Fact-checks a claim against the live web using Tavily and Exa search plus Firecrawl page reading, returning a verdict of supported, contradicted, or unclear with an explanation and source URLs.

## Facts

- Endpoint: GET https://bob.assimilatethis.com/factcheck?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-10
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/bob-fact-checker-assimilatethis-com-10a5c316
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_5cWCxK5hf7q6hqlpjDwBh

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 bob-fact-checker-assimilatethis-com-10a5c316
```

Example prompt: Can you fact-check this claim for me: 'The Eiffel Tower is taller than the Empire State Building'? I want to know if it's supported, contradicted, or unclear based on what's actually on the web right now, and see the sources.

## When to prefer this

Choose this endpoint when you need a fast, automated fact-check of a specific claim against live web content, with a clear verdicted output and source citations. Prefer it over general web search when you want a structured supported/contradicted/unclear judgment rather than raw search results. It is especially useful for debunking viral claims, validating statistics, or checking assertions in near-real-time. If you only need raw search results or a page summary without a verdict, use the sibling search or summarize endpoints instead.

## Known failure modes

- Timeout: if web search and page reading take too long, an error is returned and the user is not charged
- Unclear verdict: if sources are ambiguous or contradictory, the verdict may be 'unclear' rather than definitive
- No relevant sources found: if Tavily/Exa return no usable results, the explanation may reflect insufficient evidence
- Claim too vague: highly ambiguous or context-dependent claims may yield 'unclear' even when evidence exists
- Network/crawl failure: if Firecrawl cannot read the best page, the result may degrade in quality

## How this service works

Fact-check a claim against the live web. Searches with Tavily and Exa, reads the best page with Firecrawl, and returns a verdict (supported, contradicted or unclear), a short explanation and source URLs. Typical response 4 to 8 seconds. If it cannot answer in time you get an error and are not charged.

## Output

Returns a JSON object with three fields: 'verdict' (one of 'supported', 'contradicted', or 'unclear'), 'explanation' (a short human-readable summary of why the verdict was reached), and 'sources' (an array of URLs to the web pages used as evidence). Typical response time is 4–8 seconds. If the service cannot complete in time, an error is returned and no charge is applied.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "claim"
     ],
     "properties": {
      "claim": {
       "type": "string",
       "description": "A factual claim to check against live web sources"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "required": [
      "verdict",
      "explanation",
      "sources"
     ],
     "properties": {
      "sources": {
       "type": "array",
       "items": {
        "type": "string"
       }
      },
      "verdict": {
       "enum": [
        "supported",
        "contradicted",
        "unclear"
       ],
       "type": "string"
      },
      "explanation": {
       "type": "string"
      }
     }
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/bob-fact-checker-assimilatethis-com-10a5c316/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from bob.assimilatethis.com](https://www.zero.xyz/host/bob.assimilatethis.com/llms.txt)