OpenAI Will Watermark ChatGPT Text, But Only in the EU

On October 5, OpenAI announced textGrain, an invisible text watermark that subtly shapes the model's word choices, rolling out to ChatGPT and Codex output in the EU only to comply with EU AI Act transparency rules. API customers worldwide can opt in for select models, but it is off by default. OpenAI's own tests show that replacing 25% of words with synonyms drops detection from about 92% to about 17%, and access to the detector is initially limited to approved researchers and expert organizations.