@verify-api/mcp

@verify-api/mcp

Fact-check any claim before you act on it.

MCP server for VerifyAPI — one tool (verify_claim) that grounds an AI's answer against live web sources and returns a citable verdict with a source URL, published date, and verbatim quote.

Built for AI agents that need to catch hallucinations, verify time-sensitive facts (prices, dates, versions, standings), and cite evidence before acting.

Install

npm install -g @verify-api/mcp

Get a free API key at https://verify-api.dev/signup (no card required — 100 free verifications on signup).

Configure

Claude Desktop (claude_desktop_config.json):

{
  "mcpServers": {
    "verifyapi": {
      "command": "verifyapi-mcp",
      "env": {
        "VERIFYAPI_API_KEY": "csk_live_..."
      }
    }
  }
}

Cursor / Windsurf / any MCP client: point at the verifyapi-mcp binary and set VERIFYAPI_API_KEY in its env.

The tool

verify_claim

Verify a single factual claim against live web sources.

Input:

• claim (string, required) — one claim, ideally under 300 chars.
• as_of (string, optional) — ISO date for time-sensitive facts.
• max_wait_ms (number, optional) — soft deadline, default 15000ms.
• freshness (string, optional) — fresh bypasses cache (5x price), recent allows recent cache (2x), cached default.
• max_age_seconds (number, optional) — HTTP Cache-Control style; below 3600 → fresh tier, below 86400 → recent tier.

Output:

{
  "verdict": "supported | refuted | insufficient_evidence | out_of_scope",
  "confidence": 0.95,
  "source": {
    "url": "https://en.wikipedia.org/wiki/Python_(programming_language)",
    "title": "Python (programming language)",
    "published": "2024-...",
    "quote": "Python was created in the late 1980s..."
  },
  "receipt": "<Ed25519-signed JWT — verifiable against /.well-known/jwks.json>",
  "cost_usd": 0.02
}

Pricing

• supported / refuted — $0.02 per call
• insufficient_evidence / out_of_scope / malformed — free
• Cache hit — free
• fresh tier — 5x ($0.10), recent — 2x ($0.04)

Every verified verdict comes with an Ed25519-signed receipt you can independently verify against the JWKS at https://api.verify-api.dev/.well-known/jwks.json.

Use cases

• Catch LLM hallucinations before returning them to a user
• Verify live/time-sensitive facts the model can't know (today's price, current release, latest score)
• Cite sources with a URL + verbatim quote for compliance or transparency
• Grounded agent tools — call before executing an action that depends on a specific fact

Links

• Website: https://verify-api.dev
• API docs: https://api.verify-api.dev/v1/discover
• Machine manifest: https://api.verify-api.dev/.well-known/agents.txt
• Source: https://github.com/KyTheKitty/verifyapi
• MCP registry: https://mcp.so/servers/verifyapi