In short. GA4 assigns recognized assistant referrers to AI Assistant, while Google AI Overviews and AI Mode traffic belongs to Organic Search.
Definition: As of 17 October 2026, Google Analytics 4 (GA4) includes an AI Assistant channel in its default channel group, the predefined categories for traffic sources. Recognized assistant referrers receive the medium
ai-assistantand campaign(ai-assistant).
Key facts
- Google's 13 May 2026 announcement introduces AI Assistant traffic measurement and names ChatGPT, Gemini and Claude as examples.
- Google's default channel definitions place non-ad traffic from Google AI Overviews and AI Mode in Organic Search.
- Google's Traffic acquisition report documentation defines Session source / medium as the source and medium associated with a new session.
How does GA4 recognize assistant referrals?
A referrer identifies the site or app that sends a visit. Google's AI Assistant announcement describes automatic assignment when that referrer matches a recognized assistant. The resulting channel is AI Assistant, with these documented field values:
Medium: ai-assistant
Campaign: (ai-assistant)
The announcement names examples of assistants; its automatic assignment depends on recognition of the referrer. The campaign value provides another field to inspect alongside the channel and medium when checking these visits in acquisition reporting.
When do other channel definitions apply?
Google's channel definitions table supplies the following rules for manual traffic. Applying them to assistant visits requires examining the recorded fields:
| Recorded condition | Published channel or value |
|---|---|
Medium exactly matches ai-assistant. | AI Assistant |
Medium is referral, app or link. | Referral |
Source is (direct) and medium is (not set) or (none). | Direct |
| No channel rule matches the event data. | Unassigned |
An assistant source recorded with the medium referral matches the Referral condition. A recognized referrer receiving ai-assistant matches the dedicated assistant condition. Google separately includes AI Overviews and AI Mode in its description of Organic Search. Its channel definitions are case insensitive.
How can the classification be checked in reports?
Google's Traffic acquisition guide gives this report path:
Reports > Acquisition > Traffic acquisition
The report covers both new and returning users. Its session dimensions describe the user's most recent session. Session source identifies the publisher or inventory source, while Session medium describes the acquisition method. Session campaign exposes the campaign name associated with the session. The guide also documents searching for a traffic source in the search bar above the table.
For a separate grouping based on selected assistant sources, Google's custom channel group documentation provides an AI assistants example. Custom groups support Source and Medium conditions and can be used as primary or secondary dimensions in acquisition reports.
Related terms
- GA4 traffic acquisition
- AI referral traffic
- How do I create an AI assistants channel in GA4?
- Why can an AI referral appear as Unassigned in GA4?
FAQ
Does every assistant visit belong to Referral?
Google's published rules include a dedicated AI Assistant channel for the medium ai-assistant. Referral has its own medium conditions, including referral.
Can I change the grouping for my own analysis?
You can create a custom channel group. Google's custom group guide supports Source and Medium rules and applying custom groups to reports retroactively.
Sources
- Google Analytics Help, "Default channel group", undated
- Google Analytics Help, "What's new in Google Analytics", AI Assistant announcement, 13 May 2026
- Google Analytics Help, "[GA4] Traffic acquisition report", undated
- Google Analytics Help, "Custom channel groups", undated
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