CLAUDE WATERMARK REMOVER · MARKDOWN TEST
Why did italic formatting disappear after cleaning pasted Markdown?
Cleanup can make italics disappear: here it leaves ordinary whitespace immediately after the opening asterisk.
What changed in the preview
The original has U+200B directly after the opening asterisk, followed by a space and the word this. In the original render the parser treats the markers as emphasis. Removing the hidden character leaves a visible space next to the opener, and the second render shows both asterisks literally. Compare the delimiter surroundings when formatting changes even though the word itself survives. If the intended result is emphasis on this, place the markers directly around that word and put the normal separating space outside the opening marker.
What this test covers
This tests one asterisk pair. It does not generalize to every combination of punctuation, underscore delimiters or Markdown extensions.
Measured HTML
The first preview contains a literal U+200B, displayed below as \u200B. The HTML is shown as text.
Before cleanup
<p>Check<em>\u200B this</em> today.</p>
After cleanup
<p>Check* this* today.</p>
Reproduce locally
Save reproduce.cjs and tested-app.js together. Run npm install --no-save commonmark@0.31.2, then node reproduce.cjs. Compare with the recorded input, output and HTML. The test uses the homepage callback with a minimal DOM. It does not use Claude output or test statistical watermark detection.
See the CommonMark specification and another measured Markdown case.