OpenAI: expanding content provenance to text; EU ChatGPT/Codex watermarking, API opt-in worldwide

OpenAI says it is extending content provenance to text in response to EU regulatory requirements, "while recognizing the significant limitations of current text watermarking technology". It will watermark eligible ChatGPT and Codex text in the EU over the coming weeks, and API customers can turn on text watermarking for select models worldwide from Oct 5, 2026.

We're expanding our approach to content provenance to include text in response to EU regulatory requirements, while recognizing the significant limitations of current text watermarking technology.

Our tools already help verify whether an image or audio file was created with our models. This work builds on those efforts to help people better understand when content may have been generated or edited with an OpenAI model.

In the EU, we’ll start watermarking eligible text from ChatGPT and Codex over the coming weeks to comply with the EU AI Act.

Customers using our API can turn on text watermarking for select models worldwide today.

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Archived 2026-10-05 via fxtwitter (unofficial).