U+FEFF guide · October 25, 2026

Does Claude Text Cleaner Remove U+FEFF From Pasted Text?

Yes. When pasted text contains U+FEFF, this browser cleaner deletes that character and counts it under “Zero-width characters.” For A + U+FEFF + B, the cleaning rule produces AB: three code points become two, with one removal in one category. This is character cleanup in pasted text; it does not inspect a file's bytes or repair its encoding.

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Before · 3 code pointsA + U+FEFF + BThe middle character is invisible in ordinary text.

After · 2 code pointsABZero-width characters: 1. No replacement is inserted.

The code-point label exposes a change that the rendered letters alone do not show.

Is this the same as removing a file's BOM?

U+FEFF can represent a byte order mark at the start of an encoded stream. Unicode's BOM FAQ explains that role and its use as a zero width no-break space. This tool only receives text pasted into its input box. If a decoding step has already turned a leading BOM into a U+FEFF character in that text, the cleaner removes the character. It cannot examine the original file bytes or decide how they should be decoded.

A public Java question about a number that fails to parse shows why an invisible leading U+FEFF can matter. A separate HTML question asks how to locate an unexpected U+FEFF in page content. Those are examples of the character causing confusion, not evidence that it marks AI-generated text.

Check the right layer

Keep a copy of the original. Paste text into the cleaner and review the output and “Zero-width characters” count.
If you need to fix a source file, inspect its encoding and leading bytes in a suitable editor. The cleaner's report cannot diagnose the file itself.
Copy the cleaned text only after checking that removing any intentional format characters is acceptable.

The report counts matched code points, not their origin. It does not detect a watermark or predict an AI detector's result. See how removal counts work and why U+00A0 behaves differently.