No assistant sends both signals yet, on any surface we have tested.
Anthropic
Referrer: Partial
UTM: Missing
Referrer: Reported missing
UTM: Reported missing
Referrer: Missing
Google
Referrer: Works
OpenAI
UTM: Works
UTM: Reported works
UTM: Partial
chatgpt.com
Reported means a third-party report we have not yet verified first-hand. Select a status to see the evidence on the lab page.