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Free ai content checks tool

Check Text for AI Watermarks

Check text from Claude and other AI tools for hidden Unicode characters. Get an honest report about what text-only detection can prove.

No account requiredRuns in your browserReviewed August 13, 2026
Open the plain-text guide
Private browser check

Paste text to inspect

Your text stays in this browser. A longer sample gives the style section more context.

Your watermark report will appear here

This checks hidden Unicode characters and explains what text-only AI detection can—and cannot—prove.

How to use

How to check for AI watermarks

  1. 1

    Paste a longer text sample

    Copy a paragraph or document excerpt from Claude, ChatGPT, or another AI tool.

  2. 2

    Inspect every observable marker

    The checker looks for invisible Unicode characters, unusual spaces, and control characters in your browser.

  3. 3

    Read the detector limits

    A clean result does not prove human authorship, and a marker does not prove who wrote the underlying ideas.

Why this matters

Know what the text can show

A visible result can separate hidden-character findings from claims that need a provider’s private detector. That keeps a Claude watermark check useful without calling a guess proof.

For editors and agents

Cite this tool accurately

Use the canonical page and this short description when you reference the tool. The plain-text guide keeps the method and limits easy to read.

AI Watermark and Claude Checker — Check text from Claude and other AI tools for hidden Unicode characters. Get an honest report about what text-only detection can prove.

Guide

Read your watermark report

A scope diagram separating observable text artifacts from provider-level statistical watermark claims.
Original Mydentify scope: a browser check can report observable text artifacts, but it cannot confirm a provider's private watermark or authorship.

What this finds in Claude text

This tool finds observable text artifacts such as zero-width characters, directional controls, non-standard spaces, and control characters. Those can come from many editors or workflows, so they are clues rather than a Claude fingerprint.

Anthropic’s newly documented Claude mark is woven into model output and is not the same as a hidden Unicode character. Anthropic has not published the private detector needed to verify that statistical mark from pasted text.

Why AI detection needs caution

The style section flags a few formulaic phrases or unusually uniform sentence patterns. Human writing can contain them, and AI writing can avoid them. This is not a probability of authorship and should not be used as a high-stakes verdict.

  • A Claude mark can mean Claude processed or edited text.
  • A missing mark does not prove that AI was not involved.
  • A hidden character can come from copy and paste, not only AI.

Remove visible text artifacts

If you are preparing text for a CMS, form, or document, copy the cleaned version after reviewing each finding. Cleaning observable characters cannot remove Anthropic’s statistical watermark, and it does not change the provenance of the ideas.

When you publish the result on a public page, check whether the crawlers you choose to allow can reach it.

Questions

Questions about AI watermark checks

Can this detect the new Claude watermark?

It can find observable hidden characters and explain possible clues, but it cannot confirm Anthropic’s private statistical text watermark. Anthropic has not published the detector or enough technical detail for an independent verifier.

Does a clean result mean a human wrote the text?

No. It only means this browser check did not find the hidden characters it looks for. AI text can have no visible artifacts, and human text can contain unusual Unicode characters.

Does a marker prove Claude wrote the text?

No. A marker may show that text was processed by Claude, but it does not prove Claude created the original ideas or that the entire document came from AI.

Can I check ChatGPT and Gemini text too?

Yes. The observable-character check works on pasted text from any source. The provider-specific Claude statement still only applies to Anthropic’s documented marking system.

Is my text uploaded?

No. The check runs in your browser. The text is not sent to Mydentify’s server by this tool.

Should I use this for school or hiring decisions?

No. Use it as a debugging and education aid, not as sole evidence for grading, hiring, discipline, or legal decisions.