Can this tool tell whether Claude wrote pasted text?

Not conclusively. Claude text watermarking uses a statistical pattern across word choices rather than hidden characters or ordinary metadata. Anthropic has not released a public text detector or verification API, so this tool reports that limitation instead of inventing an authorship probability.

What can the Claude watermark checker verify?

For PNG, JPG, JPEG, and SVG files, it uses the official C2PA web SDK to read Content Credentials, inspect the validation state, and look for explicit Anthropic or Claude attribution. For pasted text, it can inspect hidden Unicode controls, word count, and document structure, but those controls are not the Claude watermark.

Does no C2PA metadata mean the file was not made by Claude?

No. Screenshots, image conversion, re-saving, and software that does not preserve metadata can remove Content Credentials. A missing manifest means the checker has no surviving provenance record to inspect; it does not prove human origin.

What does a Claude or Anthropic mark prove?

It signals that Claude or Anthropic was involved according to the available marking data. It does not establish who authored, owns, approved, or submitted the content, and it should not be treated as proof of misconduct.

Are my files or pasted text uploaded?

No. C2PA verification and text inspection run in your browser. The selected file and pasted text are not sent to Brand Armor AI or an AI model.

Can editing remove a Claude watermark?

Substantial rewriting, paraphrasing, translation, or mixing can weaken a statistical text mark. For files, screenshots, conversion, and re-exporting through software that drops metadata can remove the C2PA manifest. The checker reports existing evidence; it is not a removal tool.

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Claude Watermark Checker for Text and Image Files

Check PNG, JPG, JPEG, and SVG files for signed C2PA Content Credentials, inspect explicit Claude attribution, and understand what can and cannot be verified from pasted text.

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Tool 01

Claude Watermark Checker

Verify file provenance with the official C2PA SDK and inspect pasted text without inventing an authorship score.

Check Claude watermark evidence

Verify C2PA Content Credentials in supported images or inspect pasted text without uploading your content.

What this checker proves

Files: whether the official C2PA SDK can read and validate embedded Content Credentials.

Attribution: whether Anthropic or Claude is explicitly named in the manifest data.

Text: only document statistics and hidden Unicode controls, not Claude authorship.

Important limitations

Copying text does not expose Claude’s statistical watermark as a character sequence.

Editing, paraphrasing, translation, screenshots, and file conversion can weaken or remove marking evidence.

A mark signals Claude involvement. It does not prove who wrote, owns, or approved the content.

Private by design: file verification and text inspection run locally in your browser. Brand Armor AI does not receive the selected file or pasted text.

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The short answer

Can you check whether Claude wrote something?

For pasted text, not conclusively. Claude’s text mark is a statistical pattern distributed across word choices. It is not a visible label, a metadata field, or a string of zero-width characters that a browser can reveal. Anthropic has not released a public detector or text-verification API yet.

For supported image files, yes. Claude can attach signed C2PA provenance metadata to PNG, JPG, and SVG outputs. This page uses the official open-source Content Authenticity Initiative SDK to read those credentials locally.

This distinction matters because many “AI detector” pages turn uncertainty into a percentage. A probability score is not the same as provenance evidence, and it should not be used to accuse a student, writer, employee, or contractor of misconduct.

Text versus files

Three signals people often confuse

A Claude watermark checker needs to identify which marking system it is actually looking for. These signals are technically different and support different conclusions.

Signal	How it works	Can the public check it?	What can remove it?
Claude text watermark	Statistical word-choice pattern	Not currently available	Can weaken after substantial editing, paraphrasing, translation, or mixing
Claude file watermark	Signed C2PA Content Credentials metadata	Yes, for supported files	Can be removed by screenshots, conversion, or software that drops metadata
Hidden Unicode characters	Zero-width and directional control characters	Yes, but unrelated to Claude watermarking	Often survives copy and paste until sanitized

How to use the result

A mark is evidence of involvement, not a verdict on authorship

Choose the right checker mode

Use file credentials for a PNG, JPG, JPEG, or SVG. Use pasted text only to inspect hidden Unicode and understand verification limits.

Read the evidence, not just a badge

A valid C2PA manifest establishes a provenance record. Claude attribution requires an explicit Anthropic or Claude reference inside that record.

Treat absence carefully

No credential does not mean “human-made.” Re-saving, screenshots, and conversion can remove metadata even when the original file was marked.

How Claude text watermarking works

During generation, the model slightly favors some statistically valid word choices over others. Across enough text, those choices can form a detectable pattern while preserving normal meaning and readability.

That is why searching for unusual spaces, punctuation, or Unicode characters cannot verify the mark. The relevant evidence is spread across token choices and requires Anthropic’s detector key.

Short, factual, highly constrained, or lightly edited output may not carry enough signal for detection. Substantial rewriting can weaken it further.

How Claude file credentials work

Supported images can carry a C2PA manifest: a signed provenance record containing claims about how the asset was created or changed. The signature allows compatible software to check whether that record still validates.

A credential can name a generator, signer, source type, ingredients, and editing actions. The checker exposes those details instead of reducing the file to an unexplained yes-or-no label.

Metadata is not indestructible. A screenshot creates a new file, and some editors or conversion tools export pixels without preserving the original manifest.

Interpretation guide

What each result means

Use the narrowest conclusion the evidence supports. Provenance is useful precisely because it avoids guesswork.

Anthropic reference found

The manifest explicitly mentions Anthropic or Claude. Check its signer, generator, and validation state.

Valid credential, no Claude reference

The file has C2PA provenance, but the available record does not attribute it to Claude.

No credential found

No readable C2PA record remains. Origin is unknown, not necessarily human.

Need the official technical references?

Read Anthropic’s marking policy and the open-source C2PA JavaScript SDK used by this page.

Anthropic marking guide C2PA JavaScript SDK

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