Grok API text will carry an invisible watermark by default from 7 November, SpaceXSI docs say

The developer docs cite the EU AI Act and cover grok-4.7, 4.6, 4.5, 4.3 and the grok-4.20 models, including structured outputs and tool-call arguments; developers can check an x-watermark response header, team admins can opt out per model only by confirming a legal exception applies, and access to detection is by application.