In short. Create a custom channel group, add an AI assistants channel with Source conditions, place it before overlapping channels and inspect it in Traffic acquisition.
Definition: An AI assistants channel in Google Analytics 4 (GA4) is a traffic category defined by rules matching assistant sources. It belongs to a custom channel group, where traffic enters the first channel whose rules it matches.
Key facts
- As of 17 October 2026, Google's custom channel groups documentation includes an AI assistants example using a regex condition and channel reordering.
- Google's traffic-source definitions distinguish Source, the referring platform or location, from Medium, the type of traffic such as referral or organic.
- Google's regex documentation specifies full matching by default;
.*allows a pattern to match within a longer value. - Google's Traffic acquisition report provides Session source and Session source / medium for examining session origins.
Where is the channel created?
Google's creation instructions require Editor access or above at property level. The settings path is:
Admin > Data display > Channel groups
Selecting Create new channel group copies the default group. An existing group can also be copied. After naming the group, Add new channel creates the AI assistants category; + Add condition group opens its dimension and value conditions.
Which source rule should it use?
A regular expression, or regex, is a pattern for matching text. Google's AI assistants example uses matches regex and includes alternatives containing chatgpt and perplexity. A reduced Source rule using those alternatives is:
Channel name: AI assistants
Dimension: Source
Condition: matches regex
Value: .*chatgpt.*|.*perplexity.*
This example selects source values containing either name. It covers only those alternatives; additional assistants require additional matching rules.
Google's regex reference defines | as OR and .* as a way to match surrounding characters. These substring patterns also accept longer source values containing the same text. For a list of exact source values, literal periods use \. and alternatives can be grouped between ^ and $, the start and end anchors.
The Source definition includes websites, apps and campaign labels. The rule therefore needs to match the recorded Source value. Google's assistant example also calls for updating the regex when assistant URLs or the intended list change.
Why does channel order matter?
Google's ordering instructions assign traffic to the first matching channel. They place AI assistants above the referral channel and allow placement above Organic Search where needed. A matching category earlier in the list receives the traffic first.
After Save channel, Reorder changes the list position. Apply confirms the ordering, and Save group saves the group configuration.
How is the result checked?
Google's channel reporting instructions allow the custom group as a primary or secondary dimension in acquisition reports. In Reports > Acquisition > Traffic acquisition, selecting the custom group exposes the AI assistants row when matching data exists.
Google's Traffic acquisition documentation defines Session source / medium as the source and medium associated with a new session. Examining that dimension alongside the custom group shows the recorded sources behind the category. The report includes Sessions and Key events metrics.
Related terms
- AI referral traffic
- UTM parameters
- Why does GA4 custom channel rule order affect AI traffic classification?
- Can a GA4 custom channel group classify historical visits?
FAQ
Can I apply the group to historical reports?
Yes. Google's custom channel groups documentation allows retroactive application to reports.
Which report should I use to inspect sources?
You can use Google's Traffic acquisition report, which includes Session source and Session source / medium. Its session dimensions cover new and returning users.
Sources
- Google Analytics Help, "Custom channel groups", undated
- Google Analytics Help, "About traffic-source dimensions", undated
- Google Analytics Help, "About regular expressions (regex)", undated
- Google Analytics Help, "[GA4] Traffic acquisition report", undated
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