VerifyAPI MCP ServerVerifiedFeatured

What is VerifyAPI?

VerifyAPI is a fact-check-first MCP server. It gives AI agents one tool — verify_claim — that grounds any factual assertion against live web sources and returns a citable verdict with a source URL, published date, verbatim quote, and an Ed25519-signed receipt.

Use it any time your agent is about to act on a claim it can't cite: prices, dates, versions, quotes, statistics, product specs, event outcomes. Getting it wrong costs time, money, and trust. Verify first.

How to install

Add this to your MCP client's config (Claude Desktop, Cursor, Cline, etc):

{
  "mcpServers": {
    "verifyapi": {
      "command": "npx",
      "args": ["-y", "@verify-api/mcp@latest"],
      "env": {
        "VERIFYAPI_API_KEY": "csk_live_YOUR_KEY_HERE"
      }
    }
  }
}

No API key? Leave VERIFYAPI_API_KEY unset for the free trial (limited daily calls, no receipts). Get a free key at https://verify-api.dev/signup — no credit card required.

The one tool: verify_claim

Input:

{ "claim": "Python 3.13 was released in October 2024." }

Output:

{
  "verdict": "supported",
  "confidence": 0.99,
  "source_url": "[https://docs.python.org/3/whatsnew/3.13.html](https://docs.python.org/3/whatsnew/3.13.html)",
  "exact_quote": "Python 3.13 was released on October 7, 2024.",
  "receipt": {
    "jws": "eyJhbGci...",
    "kid": "pQAd73zRp9Xq9Y5U"
  }
}

Verdicts: supported, contradicted, unverifiable. Every supported/contradicted verdict comes with a JWS receipt signed by keys served at https://api.verify-api.dev/.well-known/jwks.json.

Why signed receipts?

"The AI checked" is not the same as "the AI verified." A signed receipt lets any downstream system — auditor, user, another agent, a smart contract — cryptographically prove that a specific claim was verified against a specific source at a specific time.

Pricing

• Free trial: no signup, no card. Limited daily calls. No receipts.
• With API key: $0.02 per verified claim. Unverifiable / out-of-scope calls are free.
• Freshness tiers: standard verification $0.02, real-time (fresh-fetch) $0.05.
• Auto top-up: save a card, set a threshold, keep flowing.

Key features

• One tool, one job. No sprawl. verify_claim(claim: string) → structured verdict.
• Real citations. Source URL + verbatim quote from that page, not a summary.
• Ed25519-signed receipts. JWS format. Verifiable against public JWKS.
• Free trial with no signup. Zero-friction try-before-you-buy.
• Fair pricing. $0.02 per verified claim. Free when we can't verify.
• Agent-native discovery. /.well-known/agents.txt and x402 payment support out of the box.

Links

• Website: https://verify-api.dev
• Signup (free, no card): https://verify-api.dev/signup
• npm: https://www.npmjs.com/package/@verify-api/mcp
• MCP Registry: io.github.KyTheKitty/verifyapi
• Source: https://github.com/KyTheKitty/verifyapi

Built by

Circuit Savers LLC — Wausau, Wisconsin.