How to paste from Claude without leaving artifacts
By Claude Watermark Research · Updated
Copying from Claude's web interface puts both plain text and HTML on your clipboard. Rich-text destinations — AO3, Google Docs, WordPress, Notion, most CMS editors — take the HTML version, including provider-specific class names. Pasting through any plain-text surface first, or using Paste as Plain Text, discards all of it. On Windows that is Ctrl+Shift+V, on Mac Cmd+Shift+V in most applications.
What is actually on your clipboard
Two representations of the same content. Plain text destinations take the text flavour and nothing else survives. Rich-text destinations prefer the HTML flavour, which carries tags, class names and data attributes from the page you copied from.
That is why the same copy-paste is invisible in one place and obvious in another. Pasting into a code editor is clean; pasting into a fic editor is not.
The habit that prevents all of it
Use Paste as Plain Text: Ctrl+Shift+V on Windows and Linux, Cmd+Shift+V on macOS in most applications. It is one extra key and it removes the entire category of problem.
If an application does not support it, route through a plain-text editor once. Notepad, TextEdit in plain-text mode, or any code editor works.
What plain-text pasting does not remove
Zero-width characters, non-breaking spaces and typographic punctuation are part of the text itself, not the formatting, so they survive a plain-text paste. They are much weaker signals — they show up in text copied from any website — but they do survive.
Nothing about pasting affects word choice, which is where a statistical watermark would live. That is a separate matter, and currently a theoretical one.
Questions
- Does Paste as Plain Text lose my formatting?
- Yes — italics, bold and links go. That is the trade-off. If you need to keep formatting, strip the class attributes from the HTML instead.
- Is this only a Claude thing?
- No. Every chat interface leaves some markup behind. Claude's happens to be the most specifically named, which is why it became the basis for a detector.
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