verification-mcp

Real-time fact-checking + citation verification + source-freshness for AI agents. Tools an agent can call mid-reasoning to ground its claims against authoritative free sources (Wikipedia, Wikidata, Crossref, Wayback Machine).

Endpoint: https://verification-mcp.prakhar-cognizance.workers.dev/mcp

What it does

The single biggest empty quadrant in the AI-agent tooling space (per 2026 ecosystem research): nobody runs a cheap, hosted, agent-callable verifier. Existing options (Vectara, Patronus, Galileo) are enterprise-priced and aimed at builders, not run-time.

This MCP lets an agent run three operations during reasoning:

Tool	What it does
`fact_check(claim)`	Searches Wikipedia + Wikidata + Crossref for the claim. Returns verdict (`supported` / `contradicted` / `mixed` / `unverified`), 0–1 confidence, source list with excerpts.
`cite_check(citations[])`	For each `{url, claim?}` (up to 25): checks the URL resolves, computes Jaccard match between the page content and the claim, surfaces retraction status (Crossref `update-to`).
`source_freshness(url)`	HTTP `Last-Modified` + most recent Wayback Machine snapshot + boolean `changed_recently` (last 90 days). Useful for RAG hygiene.

Install

// Cursor / Claude Desktop / Cline
{
  "mcpServers": {
    "verification": {
      "url": "https://verification-mcp.prakhar-cognizance.workers.dev/mcp",
      "headers": { "Authorization": "Bearer YOUR_KEY" }
    }
  }
}

Free tier: send requests without an Authorization header. 50 calls/month, 10/min.

Pricing

Tier	Price	Monthly calls	Notes
Free	$0	50	10/min ceiling. Anonymous.
Solo	$19/mo	1,000	60/min ceiling.
Team	$49/mo	5,000	200/min, all tools.
Pro	$149/mo	20,000	600/min, all tools, priority routing.

Higher than Cat-1 data MCPs because each verification call fans out to multiple upstream sources (typically 3–5 HTTP requests per fact_check).

Upgrade →

How it works

fact_check("Microsoft was founded in 1975")
        │
        ▼
  ┌──────────────────────────────────────────────┐
  │ Cloudflare Worker (verification-mcp)         │
  │                                              │
  │  Parallel fetch:                             │
  │    Wikipedia REST  /page/search?q=…          │
  │    Wikidata        /w/api.php?wbsearch…      │
  │    Crossref        /works?query=…            │
  │  ↓                                           │
  │  Jaccard token-overlap match against claim   │
  │  ↓                                           │
  │  Verdict aggregation                         │
  │  ↓                                           │
  │  KV cache (6h TTL)                           │
  └──────────────────────────────────────────────┘
        │
        ▼
  { verdict: "supported", confidence: 0.80, sources: [{Wikipedia: "Microsoft was founded by Bill Gates and Paul Allen on April 4, 1975."}, …] }

License

MIT. Upstream data is free per each provider's terms of use (Wikipedia CC-BY-SA, Wikidata CC0, Crossref free, Wayback Machine free).

verification-mcp