How to fact-check a Claude answer

To fact-check a Claude answer, have AIs from other companies go through it claim by claim, then look up anything they flag in a primary source. With the ChatRound Chrome extension that takes one click: a Check button sits under every answer on claude.ai, the report opens in Chrome's side panel next to the chat, and the corrected text goes into Claude's message box — never sent — so Claude can fix its own answer.

Add the Chrome extension Check an answer

WITH THE EXTENSION

Checking an answer on claude.ai

Add the extension

Install ChatRound from the Chrome Web Store. It asks once, in one dialog, for access to ChatGPT, Claude, Gemini and chatround.ai.

Click Check under the answer

A Check button appears under each Claude answer. To check only part of one, select the text, right-click and choose “Check with ChatRound”.

Read the report in the side panel

Two reviewers, by default from companies other than Anthropic, each answer the question themselves, then go through Claude's answer. The report gives a verdict, quotes each wrong claim with the reviewers' reasons, lists what was missed and writes a corrected answer.

Send the fix back

“Put it in Claude's message box” fills the chat's message box with the corrections. Nothing is sent: you read it, edit it if you like, and send it yourself.

PRIVACY

What leaves the page

Only the answer you click Check on, the question above it and the model's name — never the page address or the rest of the conversation. The extension hands it to chatround.ai inside Chrome, not in a URL.

No extension? Paste it

Copy the answer, or the whole conversation, from Claude and paste it at chatround.ai. Share links can't be read from here, so paste the text itself.

EXAMPLE

A Claude answer, checked

TRAVEL RULES

Back to Europe after 70 days? The 90/180 rule, checked

Claude Haiku 4.5 told a US citizen they could stay May 1–June 30 after 70 days in Spain. The check found the stay has to end on May 20.

2 wrong · 2 disputed · 2 missing

Read the check

COMMON QUESTIONS

Before you trust an answer

Why not ask Claude to check itself?

You can, and it sometimes catches a slip. But a model rereading its own answer tends to reuse the reasoning that produced it, while a reviewer from another company works the question out separately. For a Claude answer, ChatRound's default reviewers are not Anthropic's models, and neither is the model that writes the report.

Does it work with every Claude model?

Yes. It checks the answer on the page, whichever Claude model wrote it.

Does it send anything to Claude for me?

No. The corrected text is placed in Claude's message box and stays there until you send it.

Is it free?

Free to start: the free plan includes a monthly allowance of checks, and Pro raises it. The extension itself is free.

Checking another AI?

How to fact-check a ChatGPT answer · How to fact-check a Gemini answer

YOUR TURN

Check the answer you're about to rely on.

Paste an answer from ChatGPT, Claude, Gemini or any AI. Two AIs from other companies go through it and show you what's wrong.

Check an answer Add the Chrome extension

It puts a Check button under every ChatGPT, Claude and Gemini answer.