Fact Checker API

io.github.Br0ski777Published by GitHub account Br0ski777v1.1.0Updated Oct 25, 2026

Verify claims with web evidence. Returns sources and verdict. x402 micropayment.

VerifiedSSEWeb executableWeb Search & ScrapingFinance

Overview

AI-generated overview

A remote MCP server that fact-checks a claim by searching the web and returning evidence snippets, source URLs and a confidence assessment.

What you can do
Fact-check a claim by searching the web for supporting or contradicting evidence, with an optional cap on the number of sources returned (default 5, maximum 10). Returns relevant web snippets, source URLs and a confidence assessment for the claim.
When to use it
Useful when an assistant needs to verify a factual statement or gather evidence for or against a claim during a conversation. It is not intended for general web scraping, SEO analysis or sentiment analysis.
Requirements
A remote MCP endpoint added to the client configuration; no API key or signup. Each call is paid per use in USDC on the Base L2 network through the x402 protocol, so an x402-aware client and a funded wallet are needed to complete the payment challenge.
Before you install
Every fact-check call costs money (listed at $0.012 per call) in USDC on Base, settled through a crypto wallet; the payment challenge is handled by the client, so review spending limits. The claim text is sent to a third-party service that performs the web search.

Installation

In SourceWeft

  1. Open Fact Checker API in the dashboard and add it to a workspace.
  2. Enable the server for the chats that should use its tools.

Web executable via SSE. Remote servers run from the web runtime once configured in a workspace.

Use with an agent

Paste this prompt into Claude Code, Codex, Cursor or another agent — or into SourceWeft chat. The agent reads this server's install guide, shows you its publisher, endpoint and sign-in, and adds it to your client once you agree. Keys never go into a command.

Read https://sourceweft.com/mcp/io.github.Br0ski777%2Ffact-checker/install.md and connect the MCP server it describes to my client. Before changing any config, show me its publisher, endpoint and sign-in method and wait for my OK. Never put an API key in a command or in a file I would commit; ask me where it should come from.

Read the install guide the agent follows

Other MCP clients

Add this to your client's mcpServers config.

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

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.):

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

Quickstart -- HTTP (x402)

bash
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

Any x402-aware client (@x402/fetch, x402-agent-tools, ATXP) handles the 402 -> sign -> retry cycle automatically.

Tools

ToolMethodPathPriceDescription
research_check_factPOST/api/check$0.012Fact-check a claim by searching for evidence online

research_check_fact

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 URLs, and a confidence assessment. Do NOT use for general web scraping — use web_scrape_to_markdown instead. Do NOT use for SEO analysis — use seo_audit_page instead. Do NOT use for sentiment analysis — use sentiment_analyzer instead.

Parameters

NameTypeRequiredDescription
claimstringyesThe factual claim to verify (e.g., 'The Eiffel Tower is 330 meters tall')
max_sourcesnumbernoMaximum number of sources to return (default: 5, max: 10)

Example agent prompts

  • "Verify a factual claim, check if a statement is true, or find evidence supporting or contradicting a claim"

Payment

  • Protocol: x402 -- HTTP-native pay-per-call, no signup, no API key
  • Network: Base L2 (eip155:8453)
  • Asset: USDC
  • Facilitator: Coinbase CDP (primary), PayAI (fallback)

Part of klymax402

100 x402 micropayment APIs for AI agents -- one wallet, USDC on Base, zero signup.

License

MIT

Source: README.md at commit c07b0ab

Tools

0
SourceWeft has not read this server's tools yet.

Version history

1
  1. v1.1.0LatestSep 16, 2026

Score

50% of the applicable checks met

How complete this listing is, computed from the registry entry, the endpoint and public sources. Not a rating of the server and not a statement that it is safe or working today: reachability is a dated check, and no installs or reviews go into the score.

  • Reached in the last 30 daysRequired25 pts

    Keep the endpoint answering the MCP handshake; SourceWeft probes it every 30 days.

  • Auth declaredRequired10 pts

    Declare the credential headers in the registry entry, or keep the endpoint answering the probe so its auth can be classified.

  • Tools listed15 pts

    Answer tools/list without a credential, or ship a package that starts in a sandbox without one.

  • DescriptionRequired15 pts
  • Logo10 pts
  • Documentation15 pts
  • License10 pts