Mephistopheles — AI fact-check

Fact-check any AI answer: a grounded trust score plus the specific claims it got wrong, each with a real source.

Don't take an AI's word for it — check it. Mephistopheles is the accuracy layer for any AI. Highlight an answer from ChatGPT, Claude, Gemini — or any text on any page — right-click "Verify with Mephistopheles," and get an instant, grounded fact-check: a hallucination-risk score plus the specific claims the model got wrong, each with the source that contradicts it. How it works: it pulls out each factual claim, checks each one against independent sources (live web search, Wikipedia, Wikidata), and returns a per-claim verdict — supported, contradicted, disputed, or unverifiable. It flags what it can't confirm instead of guessing, so you know exactly what to trust and what to double-check. • Works on any site — ChatGPT, Claude, Gemini, or anything you're reading • Right-click to verify a selection, or click the toolbar icon and paste • Cited, not guessed — every flag points to real evidence • Nothing is stored — the text you check is used only to produce the result Free to try. For heavier use, sign in at mephistopheles.ai.