Lenz

Lenz runs an independent fact check on your text, or on the answer ChatGPT just gave you — that's how you catch an error or a hallucination before it reaches anyone.

What to type. You don't have to name Lenz. Ask in your own words: "Double-check that last number you gave me." "Fact-check this section before I send the newsletter." "Is it true that 90% of startups fail within their first year?" Or say "check it with Lenz".

What it's for. A statistic, a legal or compliance point, a medical or scientific claim, a historical detail: any statement that can be checked, in a newsletter, a report or a post before it goes out. It does not grade an opinion or a prediction, and it tells you when that is what you gave it.

Two checks. Start with the quick check: a verdict on each claim (True, Mostly True, Mixed, Mostly False or False), how confident Lenz is, and usually a reviewer's short reasoning, in about fifteen to twenty seconds. The reasoning is a reviewer's note, not a checked source. When something needs to hold up, ask for the deep check. It investigates the claim against independent public sources and shows a score out of 10, the key finding, the caveats and the main sources, in about a minute to a minute and a half. You can then ask follow-up questions grounded in that evidence. The deep check can change the quick verdict. When it does, rely on it: it shows its sources.

The result card. Each check comes back as a card. From it you can start the deep check on a claim, open a source, or pick which claims in a draft to check in depth.

Lenz is unaffiliated with any model vendor. No verdict is infallible, which is why the deep check shows its work. The connector is open source: https://github.com/lenzhq/lenz-mcp

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