What Anthropic has published
Anthropic says supported Claude models embed a watermark directly into generated text. The mark travels with copied text and may persist through some editing. The company also describes signed provenance metadata for supported generated files.
What remains unpublished
Anthropic says technical details about detection mechanisms are forthcoming. Without that mechanism and an official detector interface, an independent browser tool cannot honestly declare text fully detected or fully clean.
Why hidden Unicode is different
Zero-width spaces, byte order marks, unusual spaces, and directional controls are concrete Unicode code points. They can be introduced by editors, websites, language-specific typography, clipboard transformations, or generated output. Their presence is not proof of Claude authorship, and their absence is not proof that no statistical watermark exists.
Detection has stated limits
Anthropic notes that a detected mark is a signal, not complete proof of provenance. It also says a missing detectable mark does not prove the content was not AI-generated or processed. Heavy editing, paraphrasing, translation, mixing, or very short passages can weaken reliable detection.
Use a Unicode inspector for text hygiene. Use official detection tools, once released, for supported Claude marks. Treat either result as evidence with limits—not a complete authorship verdict.
Source: Claude Help Center: How Claude marks AI-generated content. Continue with the detection explanation, the careful removal guide, or the Claude Code answer.
Clear answers, narrow claims
Claude text watermark FAQ
Which Claude models watermark text?
Anthropic says marking applies to supported Claude models and that it is still adding support to earlier models. Availability depends on whether the model, product surface, platform, and marking type support it; check the official article for current coverage.
Does copying and pasting remove the Claude text watermark?
Anthropic says the watermark is part of the text, travels with copied text, and may persist through some editing. It is not described as clipboard metadata or a single hidden character.
Does Claude watermark text outside the EU?
Anthropic says marking applies wherever supported Claude models are offered, worldwide, including Claude Platform, Claude, Claude Code, Claude Cowork, Claude Tag, and supported cloud partners.
Can this site detect Claude’s official text watermark?
No. Anthropic says detection details are forthcoming. This site checks exact hidden Unicode and formatting artifacts only, without assigning an official or invented watermark score.
Inspect the observable layer
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