OpenAI adds watermarks to ChatGPT and Codex text to comply with EU rules
Announced October 5, 2026
What happened
OpenAI published its text watermarking policy in response to EU text provenance requirements. The official post explains which text the watermark covers, how detection works, and that researchers will be the first to get access to detection. According to TechCrunch, OpenAI will embed invisible watermarks in ChatGPT and Codex text in the EU to comply with the EU AI Act. OpenAI said editing the text may make the watermark harder to detect.
Provider claims
OpenAI said that editing the text may make the watermark harder to detect.
Why it matters
This is a case of a major LLM provider meeting the EU AI Act's text provenance obligations with actual watermarking. It may set a benchmark for how other providers respond and how widely detection tools are made available.
Sources
- Official Our approach to EU text provenance rules OpenAI
- Press OpenAI will start watermarking ChatGPT’s text in the EU TechCrunch
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