Added during sampling by adding a bias to token probabilities in places where several tokens are equally likely.
Reading their technical report https://cdn.openai.com/pdf/e9508624-d767-41b6-a26d-e34ca798a... it's a bit more complicated than that, but yes, the watermark is added during sampling.
alt Hacker News
Reading their technical report https://cdn.openai.com/pdf/e9508624-d767-41b6-a26d-e34ca798a... it's a bit more complicated than that, but yes, the watermark is added during sampling.