verify-anything

verify — is this true?

npx verify-anything "The Eiffel Tower is located in Berlin. It is 330 metres tall and was completed in 1889. Apollo 13 landed on the Moon in 1969."

✗ The Eiffel Tower is located in Berlin.
   █░░░░░░░░░ 10%  Evidence contradicts the claim (en.wikipedia.org +1)
   ↳ https://en.wikipedia.org/wiki/Eiffel_Tower
   “The Eiffel Tower is a lattice tower on the Champ de Mars in Paris, France.”

✓ The Eiffel Tower is 330 meters tall.
   ████████░░ 77%  Directly supported by 1 source (single source)
   ↳ https://en.wikipedia.org/wiki/Eiffel_Tower
   “Eiffel Tower. Height Architectural 300 m (984 ft) Tip 330 m (1,083 ft)”

✓ The Eiffel Tower was completed in 1889.
   ████████░░ 80%  Directly supported by 1 source (single source)
   ↳ https://en.wikipedia.org/wiki/Eiffel_Tower
   “Eiffel Tower. Construction started 28 January 1887 … Completed 31 March 1889”

✗ Apollo 13 landed on the Moon in 1969.
   █░░░░░░░░░ 10%  Date mismatch — the claim's date does not match the source
   ↳ https://en.wikipedia.org/wiki/Apollo_13

Verdict: 2 ✓  2 ✗  0 ?   2 contradicted

(Real output, 2026-10-17, --thorough. The quoted line under each verdict is the exact span the verifier judged — so you can check the check. --verbose prints every source it weighed.)

Every AI answer, every page an agent reads, every claim in a doc — nobody can tell what's true. verify takes any input, extracts every factual claim, and judges each one against live web evidence: verified / contradicted / unverified, with confidence, the source, and the reason.

• Any input — a sentence, a paragraph, a URL, a file, or stdin (paste a ChatGPT answer)
• Every agent — verify mcp exposes a verify tool; verify setup adds it to Claude Desktop, Claude Code, Cursor, Windsurf, Codex and Gemini CLI in one command. Your agent gets a conscience: verify before you answer.
• Real verification, not vibes — claim-level NLI entailment against fetched sources, cross-source consensus, contradiction detection, live citation checks. Powered by the open LastSearch engine.
• Honest — confidence is an evidence-based estimate, not a guarantee; sources are shown so you can check.

Use

npx verify-anything "<text>"            # a claim or paragraph (50+ chars)
npx verify-anything https://example.com # a page
npx verify-anything report.md           # a file
pbpaste | npx verify-anything           # whatever's on your clipboard
npx verify-anything ... --verbose       # every source judged, with entailment / contradiction scores
npx verify-anything ... --json          # machine-readable; exit code 1 if anything is contradicted

Keyless use is rate-limited. Get a free key at lastsearch.ai and export LASTSEARCH_API_KEY=ls_...

Give your agent a conscience

npx verify-anything setup        # registers the MCP server with your installed clients

Then: "Draft the answer, then run verify on it before you show me."

Library

import { verifyText } from "verify-anything";
const r = await verifyText("...", { depth: "thorough" });
r.claims.forEach(c => console.log(c.status, c.confidence, c.text));

Limits (read this)

Verification is only as good as the evidence found and the verifier reading it. It will miss things and occasionally be wrong; thorough (the default) uses the stronger verifier. Treat the output as a fast, sourced second opinion — not an oracle.

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