---
title: "Claude Watermark Checker & Detector | Unicode Scan"
description: "Check Anthropic's current Claude watermark detector/API status, then scan hidden Unicode locally. Free, private and never presented as an official verdict."
url: "https://maksut.net/claude-watermark-checker/"
language: "en-US"
datePublished: "2026-08-15T03:16:45+00:00"
dateModified: "2026-09-23T20:22:26+00:00"
author: "Maksut"
---

Free local inspection · Official detector status

# Claude Watermark Checker & Detector | Unicode Scan

Check whether Anthropic's official Claude watermark detector/API is available, then scan text locally for hidden Unicode. The tool is private and free, but it does not produce an official watermark verdict.

[Inspect text locally](#cwc-input) [See how to read the result →](#cwc-guide)

Runs locally · No account required · No text storage

**Official status — reviewed August 27, 2026:** Anthropic says Claude uses a version of SynthID-Text and that an official watermark detection API is coming soon. The API is not publicly available to this checker today, so official verification remains unavailable. [Read Anthropic's technical explanation](https://www.anthropic.com/news/claude-text-watermark).

Evidence boundary

## What this Claude watermark checker can verify today

| Evidence layer | Current status | What this page does |
| --- | --- | --- |
| Claude statistical text watermark | Official API announced; not public | Reports verification as unavailable; never invents a probability. |
| Hidden or unusual Unicode | Locally inspectable | Lists exact code points, counts, context, and conservative cleanup options. |
| C2PA file provenance | Relevant to supported files, not pasted text | Does not accept or verify files; use a C2PA-aware credential tool. |

Need the mechanism, rollout limits, code/proofreading caveats, and SynthID-Text explanation? [Read the full Claude text watermark guide](https://maksut.net/claude-text-watermark/).

## Paste text to inspect

Your text is analyzed locally in your browser for the currently available checks.

0 characters · 0 words

A hidden-character scan is not a Claude watermark test. Claude’s text watermark is statistical, so this tool does not claim official verification unless a supported verification provider is available.

## Analysis results

How to read the result

## Inspect text integrity without overstating provenance

Start with the official verification status. When it is unavailable, the rest of the report is a local integrity inspection: it can reveal hidden Unicode and explain sample structure, but it cannot identify a human or AI author.

1. Paste a representative passage and run the local analysis.
2. Review every unusual character in context before removing it; some are legitimate language or formatting characters.
3. Use the cleaned-copy preview only when you have confirmed that the selected invisible characters are unwanted.

WordPress publishing

## Need a clearer review and publishing process?

I can help implement WordPress editorial roles, review steps and custom publishing features. Describe the problem and your website; we can agree a practical scope. This checker does not prove who wrote a passage.

[Explore WordPress development →](https://maksut.net/services/wordpress/) [Discuss your publishing workflow →](https://maksut.net/contact/?svc=WordPress&intent=tool-claude_checker#contact-form)

## Frequently asked questions

Clear boundaries for a privacy-first local inspection.

**Can this tool verify an official Claude watermark?**

Not today. Anthropic has announced a Claude watermark detection API, but it is not yet publicly available. This tool therefore reports official verification as unavailable instead of inferring authorship from hidden characters, punctuation, or writing style.

**Does Claude currently watermark generated text?**

Anthropic says Claude models launched in the EU on or after August 2, 2026 support machine-readable marking at launch, while support for earlier models is being added progressively. A missing or unavailable verification result therefore cannot prove that text is human-written.

**Is the Claude watermark hidden Unicode or SynthID?**

Anthropic says Claude uses a version of Google DeepMind's SynthID-Text approach. Nothing is added as a secret character: the statistical signal is created through otherwise-valid word choices during generation. Hidden Unicode is a separate text-integrity issue.

**How can I detect Claude's official text watermark today?**

You need Anthropic's compatible detector and watermark key. Anthropic says a detection API is coming soon, but no public production API is available for this checker yet. Until that changes, third-party Unicode scans and generic AI scores are not official verification.

**Can this tool remove Claude's statistical watermark?**

No. The cleaned-copy option removes only selected invisible Unicode characters. Anthropic says Claude's watermark is a statistical pattern in generated word choices, so Unicode cleanup must not be described as watermark removal.

**Does hidden Unicode prove that text came from Claude?**

No. Zero-width characters, non-breaking spaces, bidirectional controls, and variation selectors can come from copy-paste workflows, editors, languages, accessibility tools, or malicious manipulation. They are inspection signals, not proof of source or authorship.

**Does my pasted text leave my browser?**

No. The scanner, counts, suitability heuristic, cleaning preview, and copy action run in your browser. This page has no text-analysis API endpoint and does not store pasted content.

**What does sample suitability mean?**

It is a transparent structural heuristic based on length, prose continuity, repetition, and code-like content. It only indicates whether text could be useful to inspect if an official statistical method becomes available; it is not a watermark result.

## Continue with the AEO Toolkit

Use the local text inspection alongside page-readiness and structured-data checks.

- [Toolkit hub AEO Toolkit](https://maksut.net/ai-search-optimization-tools/)
- [On-page AEO Readiness Checker](https://maksut.net/aeo-visibility-checker/)
- [Structured data JSON-LD @graph Generator](https://maksut.net/json-ld-graph-generator/)

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```