Fact-check any claim with live web sources. Ed25519-signed receipts. Catches hallucinations.
Fact-check any claim before you act on it. One tool. Live web sources. Cryptographically signed receipts.
What it does: VerifyAPI is a Model Context Protocol server that verifies factual claims against live web sources and returns a citable verdict — including the source URL, published date, a verbatim quote, and an Ed25519-signed receipt so downstream systems can prove the check actually happened.
When to use it: Any time your agent is about to act on a factual claim it can't cite. Prices, dates, versions, quotes, statistics, product specs, event outcomes. If getting it wrong would cost time, money, or trust — verify first.
{
"mcpServers": {
"verifyapi": {
"command": "npx",
"args": ["-y", "@verify-api/mcp@latest"],
"env": {
"VERIFYAPI_API_KEY": "csk_live_..."
}
}
}
}
No API key? Leave VERIFYAPI_API_KEY unset for the free trial (limited to 3 calls per IP per 24h, signed receipts included). Get a free key at https://verify-api.dev/signup — no credit card required.
verify_claimInput:
{
"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",
"exact_quote": "Python 3.13 was released on October 7, 2024.",
"reasoning": "Multiple authoritative sources confirm...",
"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.
Because "the AI checked" is not the same as "the AI verified." A signed receipt lets a downstream system — compliance auditor, user, another agent, a smart contract — cryptographically prove that a specific claim was verified against a specific source at a specific time by VerifyAPI's known public key. It's the difference between saying "trust me" and handing over a notarized document.
POST /v1/balance/autorefill.LangChain / LlamaIndex agents: wrap verify_claim as a Tool. Have your agent call it before returning any factual answer.
Cursor / Cline coding agents: verify version numbers, API existence, deprecation status before writing imports.
Claude Desktop workflows: "Verify this quote is real before I put it in the deck."
Multi-agent systems: pass receipts between agents to prove groundedness up the chain.
Compliance-sensitive automation: keep the JWS receipts as audit trail for every factual decision the agent made.
| Variable | Required | Default | Description |
|---|---|---|---|
VERIFYAPI_API_KEY | No | (unset = trial) | Your VerifyAPI key (csk_live_...). Get one free at https://verify-api.dev/signup |
VERIFYAPI_BASE_URL | No | https://api.verify-api.dev | Override the API base URL. Useful for self-hosting or testing. |
curl -X POST https://api.verify-api.dev/v1/verify \
-H "Authorization: Bearer csk_live_..." \
-H "Content-Type: application/json" \
-d '{"claim": "Bitcoin ETFs were approved by the SEC in January 2024."}'
Full OpenAPI spec: https://api.verify-api.dev/openapi.json
x402 payment support built in — see https://verify-api.dev/agents.txt for the agent-native discovery manifest.
Circuit Savers LLC — Wausau, Wisconsin.
MIT
Source-derived launch command. Check the maintainer’s required arguments and credentials before running:
npx -y @verify-api/mcpMerge this template into ~/Library/Application Support/Claude/claude_desktop_config.json. Keep existing servers. Add any arguments, credentials, and permissions required by the maintainer; this template has not been install-tested.
{
"mcpServers": {
"io-github-kythekitty-verifyapi": {
"command": "npx",
"args": [
"-y",
"@verify-api/mcp"
]
}
}
}Restart Claude Desktop completely for changes to take effect. Confirm the server appears connected in the client’s tool list, then try a read-only example from its documentation.
Claude Desktop setup reference@verify-api/mcpnpmVerifyAPI — fact-check with signed receipts works with any MCP-compatible client. Copy the config snippet from the Configuration section above and add it to the file shown for your client, then restart the application.
~/Library/Application Support/Claude/claude_desktop_config.jsonRestart Claude Desktop completely for changes to take effect.~/.cursor/mcp.jsonRestart Cursor for changes to take effect..vscode/mcp.jsonReload VS Code window for changes to take effect.~/.codeium/windsurf/mcp_config.jsonRestart Windsurf for changes to take effect..mcp.jsonSave at the project root, then start Claude Code in that project and review the MCP server approval prompt. Keep real credentials out of shared files.