GA4's AI Assistant channel: what it tracks and what it misses.
Since May 2026, GA4 sorts AI referrals into their own channel automatically. It is a big improvement. It is also incomplete, not retroactive, and blind to most app traffic.
For two years, tracking AI traffic in GA4 meant a regex in a custom channel group. In May, Google built it in. Here is what that does and doesn't change.
What changed
On 13 May 2026 Google added an "AI Assistant" channel to GA4's Default Channel Group. When a session's referrer matches a recognised AI assistant, three things happen automatically: the medium becomes ai-assistant, the session is grouped under the AI Assistant channel, and the campaign dimension gets the reserved (ai-assistant) label. Coverage reports say the channel took until around mid-June to appear in many properties.
Which assistants it recognises
Google hasn't published the full list. Its announcement, as reported by Search Engine Journal, named ChatGPT, Gemini and Claude as examples. Terminus, reading Google's channel documentation, lists ChatGPT, Gemini, DeepSeek, Copilot and Grok, and reports Claude and Perplexity landing in Referral. The sources conflict, so check your own data.
Quick test: in Traffic acquisition, filter Session source to claude.ai and perplexity.ai and look at the Session medium. If it says "referral", the native channel isn't catching them in your property.
What it misses
| Gap | Why | Fix |
|---|---|---|
| History before May 2026 | The change is not retroactive | A custom channel group, which applies to historical data |
| Assistants not on Google's list | The list is unpublished and changes | Custom group with your own regex |
| Mobile app clicks | Apps often send no referrer, so sessions land in Direct | Watch utm_source=chatgpt.com, which ChatGPT adds to many links |
| Which question was asked | Referrers carry the domain, not the prompt | A prompt panel, not analytics |
Set up a custom channel group
- Admin → Data display → Channel groups → Create new channel group (copy the default).
- Add a channel called "AI assistants" with the condition Session source matches regex.
- Paste a regex covering the assistants you care about. Our free GA4 AI traffic regex generator builds it and splits it if it passes GA4's 256-character limit.
- Move the channel above Referral and save. Switch Traffic acquisition to your custom group.
Use the native channel for quick reads and the custom group for anything you report on. Then compare AI sessions with organic search sessions on the same landing pages, and you will see which pages AI assistants send people to.
Questions people ask
Does GA4 have an AI traffic channel?
Yes. Since 13 May 2026, GA4's Default Channel Group includes an AI Assistant channel and sets the medium to "ai-assistant" for recognised AI referrers.
Is GA4's AI Assistant channel retroactive?
No. Sessions before the change are not reclassified. A custom channel group, which does apply to historical data, can show AI traffic from before May 2026.
Does GA4's AI channel include Claude and Perplexity?
Sources disagree and Google hasn't published the full list. Check your own Traffic acquisition report for claude.ai and perplexity.ai and add a custom channel group if they show as referral.
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