As of July 31, audio generated with GPT-Live through ChatGPT Voice and the OpenAI API carries SynthID, the invisible watermark technology developed by Google DeepMind, embedded in the sound itself so it survives compression and editing. OpenAI's public verification tool now detects provenance signals in audio as well as images, and a new verification API lets companies build the check into their own products. It extends the C2PA-plus-SynthID stack OpenAI adopted for images in May.