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Fact Checker API

br0ski777/fact-checker-x402

Built for verifying factual claims by pulling web evidence and returning a verdict with sources. Uses the x402 micropayment protocol, so you'll pay per check through Klymax's hosted API. The repository itself is sparse on implementation details, but the setup is straightforward: point your MCP client at the SSE endpoint and you get a fact checking tool without running your own search infrastructure or LLM pipeline. Reach for this when you need to validate claims in user input, content moderation workflows, or research assistance, and you'd rather pay per query than manage rate limits and API keys across multiple search providers.

tool
1
transport
SSE
last updated
May 16, 2026
View on GitHub

Tools

1 tools

Public tool metadata for what this MCP can expose to an agent.

research_check_factUse this when you need to verify a factual claim, check if a statement is true, or find evidence supporting or contradicting a claim. Accepts a claim text and returns relevant web snippets, source URL2 params

Use this when you need to verify a factual claim, check if a statement is true, or find evidence supporting or contradicting a claim. Accepts a claim text and returns relevant web snippets, source URL

Parameters* required
claimstring
The factual claim to verify (e.g., 'The Eiffel Tower is 330 meters tall')
max_sourcesnumber
Maximum number of sources to return (default: 5, max: 10)

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Readme

Fact Checker API

MCP Server x402 License: MIT

Fact-check claims by searching the web and returning relevant evidence snippets. Pay-per-call via x402 (USDC on Base L2) -- no API key, no signup, no rate-limit wall.

Part of the klymax402 marketplace -- 100 x402 micropayment APIs for AI agents, one wallet, USDC on Base.

Quickstart -- MCP

Add to your MCP client config (Claude Desktop, Cursor, ElizaOS, etc.):

{
  "mcpServers": {
    "fact-checker": {
      "url": "https://fact-checker.api.klymax402.com/mcp"
    }
  }
}

Quickstart -- HTTP (x402)

curl -X POST "https://fact-checker.api.klymax402.com/api/check" \
  -H "Content-Type: application/json" \
  -d '{"claim":"..."}'
# -> 402 Payment Required, with an x402 payment challenge in the response body

View the full README on GitHub

Details

Repository
github.com/br0ski777/fact-checker-x402
Website
github.com/Br0ski777/fact-checker-x402
Transport
SSE
Registry
MCP registry, active

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