At the end of September, Google began adding UTM parameters to the links Gemini cites in its answers. The change was not announced, it surfaced in a Reddit thread on r/SEO, where Google’s John Mueller replied that he could see the tags too – Search Engine Journal reported it on 1st October.
Most of the coverage has treated this as a fix. Gemini traffic that used to disappear into Direct can now be attributed. That is true, but for brands using GA4’s new AI Assistant channel, a tracking tag may also change where Gemini sessions are classified. It also does nothing for the Google AI surfaces that generate most AI citations.
The question worth asking is whether the number in their dashboard means what they think it means.
What actually changed
UTM parameters are short tags added to the end of a URL that tell analytics tools where a visit came from. Gemini now appends utm_source=gemini to the links it cites. Google has not documented the behaviour, so it is not yet known which Gemini surfaces apply it or under what conditions.
The change also lands on top of another one. On 13th May 2026, Google added an AI Assistant channel to GA4’s Default Channel Group, covering sources such as ChatGPT, Gemini, DeepSeek, Copilot and Grok. Google’s documentation explicitly excludes AI Overviews and AI Mode, which are counted as Organic Search.
Why this should be on your agenda
Your Gemini numbers may move
GA4 currently places Gemini visits in its AI Assistant channel by reading the referrer, but some users have reported inconsistencies across device types. Whilst this update should help, it’s worth noting that if GA4 reads the tag and finds no medium value, Gemini visits could land in Unassigned.
That could make Gemini traffic look like it is falling when it is actually growing. Before reporting on Gemini traffic since late September, check which channel it is landing in.
Most AI citations still can’t be tracked
ChatGPT and Gemini, the two engines that tag their links, supplied only 18% of AI citations in the same study. Most of the rest came from AI Overviews and AI Mode and GA4 counts those clicks as ordinary organic or paid search. A brand can look as though AI sends it little traffic when most of it is hidden inside organic.
What to do about it
- Audit Gemini sessions since late September. In GA4, look at session source gemini without filtering by medium or channel and compare it with gemini.google.com referral sessions before the change.
- Build a custom channel group for AI traffic. The default channel group cannot be edited. A custom group can catch both referrer-based and UTM-based AI sources, so Gemini is reported consistently however the session arrived.
- Separate AI Overviews and AI Mode from organic. Neither GA4 nor this change isolates them. Track which priority queries trigger an AI Overview that cites the brand and read Search Console trends for those pages next to organic sessions.
- Report brand mentions alongside clicks. On Gemini in particular, a large share of visibility will probably never produce a session. Mention and citation tracking across engines and markets fills the part of the picture that click data cannot.
Google has made one of its AI surfaces easier to count. The surfaces it controls most closely, AI Overviews and AI Mode, remain folded into organic search. Until that changes, the AI line in most dashboards will mostly reflect which engines tag their links.
If you would like to understand where your AI traffic is really landing in GA4, get in touch with our team.
Sources
- Search Engine Journal: Google Gemini Adds UTM Parameters For Referral Attribution (1st October 2026)
- Google Analytics Help: Default channel group
- Google Analytics Help: Traffic-source dimensions, manual tagging, and auto-tagging
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