Summary
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.
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Public tool metadata for what this MCP can expose to an agent.
1 tools
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
claimstringThe factual claim to verify (e.g., 'The Eiffel Tower is 330 meters tall')
max_sourcesnumberMaximum number of sources to return (default: 5, max: 10)
Fact Checker API
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
Any x402-aware client (@x402/fetch, x402-agent-tools, ATXP) handles the 402 -> sign -> retry cycle automatically.
Tools
| Tool | Method | Path | Price | Description |
|---|---|---|---|---|
research_check_fact | POST | /api/check | $0.012 | Fact-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
| Name | Type | Required | Description |
|---|---|---|---|
claim | string | yes | The factual claim to verify (e.g., 'The Eiffel Tower is 330 meters tall') |
max_sources | number | no | Maximum 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.
- Catalog: https://klymax402.com/llms.txt
- Full API reference: https://klymax402.com/llms-full.txt
- Live stats: https://klymax402.com/stats
License
MIT
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Plug Mailtrap into your AI workflow and let it handle the email.
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Install now →Make coding agent sessions - Searchable, Shareable, Vendor-neutral & Scored.
Try For Free →Your agent targets a perfect 10 Code Health score. Deterministic. Every commit.
Try For Free →Integrate web data into your AI product. One API to scrape website & brand data.
Get API Key Now →belt cli automatically finds the best tools and skills for your agent. image, video, music, tts...
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