Guides
What AI watermarking actually is, who does it, and how to check your own text. Written to be accurate rather than alarming.
Anthropic's watermark
Does Anthropic watermark Claude's text? Yes — since August 2026
Anthropic now embeds an invisible watermark in Claude's text output. What it is, what it proves, and what Anthropic itself says degrades it.
4 min readCan you remove Anthropic's text watermark?
An honest answer: what degrades a statistical watermark, what cannot touch it, and why nobody can currently verify the result.
3 min readEU AI Act Article 50: why every provider is watermarking text now
The regulation that became enforceable on 2 August 2026, what it requires, and why Anthropic applied it worldwide instead of only in Europe.
2 min readWhich providers watermark
Does ChatGPT watermark its text?
What OpenAI has researched, what it has actually deployed, and what remains detectable in GPT output.
2 min readWhat SynthID-Text is and how statistical text watermarking works
Google shipped the first text watermark and documented it. Understanding SynthID explains how Anthropic's new Claude mark most likely behaves too.
2 min readHidden characters
Zero-width characters: the invisible marks that really are in your text
ZWSP, ZWNJ, ZWJ, word joiners and the BOM. What they are, why they survive copy-paste, and how to find every one.
2 min readUnicode tag characters: how a whole message hides inside plain text
The U+E0000 block renders as nothing anywhere. It can carry an entire hidden payload attached to ordinary words.
2 min readVariation selectors: the second invisible carrier
U+FE00-FE0F and the supplement block ride invisibly on ordinary letters. A quieter hiding place than zero-width characters.
1 min readHow to audit a document for hidden characters
A practical checklist for checking any text you did not write yourself, and for verifying that cleanup actually worked.
2 min readStylistic markers
Why AI text is full of em dashes
The em dash is the most reliable typographic tell in model output. Why it happens, and why replacing it is safe.
2 min readThe words that give away AI writing
The vocabulary that appears far more in model prose than human writing, why it clusters, and what to do about it.
2 min readDetection
Guides
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