GA4's AI Assistant Channel: What It Counts, What It Misses, and the Regex for the Rest

GA4's AI Assistant channel counts visits whose referrer Google recognizes as an AI assistant, and nothing else. It is a useful floor, not a total. AI-driven visits also land in Referral (assistants Google doesn't recognize), Organic Search (AI Overviews and AI Mode, by design), and Direct (clicks that lost their referrer). A custom channel group with one regex recovers most of the Referral leak. Nothing in GA4 recovers the other two, so you estimate them and say so.

This guide is for Shopify and DTC merchants, and the agencies reporting for them, who opened GA4 after May 2026, saw a new channel, and want to know whether to trust it. Every rule here comes from Google's Analytics Help and release notes, or Shopify's help center, listed under Sources. It is one part of our guide to AI traffic attribution, which covers the other tools (Shopify Analytics, Search Console, server logs).

AI Assistant channel (GA4)

A channel in GA4's default channel group for visits from AI assistants such as ChatGPT, Gemini, Deepseek, Copilot and Grok. Its rule is that the medium exactly matches ai-assistant. GA4 sets that medium, and the campaign (ai-assistant), when the referrer matches Google's list of AI assistants. Google says the channel excludes its own AI Overviews and AI Mode.

What does GA4's AI Assistant channel actually count?

Google's default channel group definitions give the rule in one line: the medium exactly matches ai-assistant. You don't set that medium. GA4 assigns it, along with the campaign name (ai-assistant), when the visit's referrer matches a list of AI assistants that Google maintains.

Two Google pages name different examples. The channel description lists ChatGPT, Gemini, Deepseek, Copilot and Grok. The May 13, 2026 release note, titled "New AI Assistant traffic measurement", gives ChatGPT, Gemini and Claude. Neither page publishes the full list, and neither names Perplexity. Check where each assistant's sessions actually land in your property before you report a number.

The release note doesn't say whether sessions before May 13, 2026 were reclassified. Before you chart this channel year over year, find the date its first sessions appear in your property. Earlier visits sit in Referral, so the jump is a labelling change, not new traffic.

Default channel group

GA4's built-in set of rules that sorts every session into a channel such as Organic Search, Paid Search, Referral, Direct or AI Assistant, based on source, medium and campaign. Google says you can't edit it. You can copy it into a custom channel group and change the copy.

Where does AI traffic go when the AI Assistant channel misses it?

An AI-driven visit lands in one of five places in GA4, or never reaches it. Which one decides whether you can recover it or only estimate it.

A regex fixes the Referral row. Organic Search and Direct are structural: no GA4 setting moves AI Mode out of Organic Search or gives a visit its referrer back. The last row is the one most reports forget, because the sale is real but the tag never loaded.

Why can't GA4 split out AI Overviews and AI Mode?

Because Google decided they are search. The default channel group's Organic Search description explicitly includes Google's AI Overviews and AI Mode, and the AI Assistant description explicitly excludes them. A visit from an AI Overview link carries a Google referrer, just like a classic blue-link click, so GA4 has nothing to tell them apart.

Search Console doesn't separate them either. Google's AI features documentation says AI Overviews and AI Mode traffic is included in the Performance report under the Web search type, inside your overall search numbers. So any figure for "AI Mode traffic" is an estimate built from patterns, not a count. How AI Mode traffic hides in Organic Search covers the estimation methods and how wide their error bars are.

Why does some ChatGPT traffic show up as Direct?

GA4 puts a session in Direct when the source is exactly (direct) and the medium is (none) or (not set). That is what happens when a visit arrives with no referrer and no campaign tags. A shopper who copies a product link out of an AI answer and pastes it into a browser, or opens it from a desktop or mobile app that doesn't pass a referrer, looks exactly like someone who typed your URL.

The AI Assistant channel can't see these visits, and neither can any custom channel group, because the information that would identify them never reached GA4. The honest move is to say so in your report rather than inflate the AI number. For a directional signal, compare Direct sessions landing on deep product pages with those landing on your homepage. A rise in the first, with no email or offline campaign to explain it, is consistent with AI-driven visits. It isn't proof, and it doesn't belong in a revenue total.

What regex catches the AI traffic GA4's channel misses?

In a custom channel group, add a condition where Source matches regex:

.*(chatgpt|openai|perplexity|gemini\.google|bard\.google|copilot|claude\.ai|deepseek|grok|meta\.ai|chat\.mistral|you\.com|phind|poe\.com).*

Google's regex help page says Analytics uses full regex by default: the pattern has to match the whole value, not just part of it. That is why the pattern starts and ends with .*. Without them, chatgpt would match only a source that is exactly "chatgpt", and miss chatgpt.com. The dots inside domain names are escaped (\.) so they match a literal dot rather than any character.

The alternatives cover ChatGPT and OpenAI, Perplexity, Gemini and the old Bard domain, Microsoft Copilot, Claude, Deepseek, Grok, Meta AI, Mistral's Le Chat, You.com, Phind and Poe. It is the pattern our report template ships with, so the two will agree.

Google publishes its own example on the custom channel groups page: a channel called "AI assistants" with a matches-regex condition covering ChatGPT, Gemini, Copilot, Perplexity and Bard. It is broader than ours. Its .*gpt.* alternative catches any source containing "gpt", and another alternative catches any source ending in "ai". Ours names domains instead, which trades a little coverage for fewer false positives. Either is defensible. Pick one, write it down, and don't switch mid-year.

Custom channel group

A copy of GA4's default channel group that you can edit: add channels, change conditions and reorder them. Traffic goes to the first channel whose definition it matches. Standard properties can have two custom groups, 360 properties five, each with up to 50 channels. Google says custom groups can be applied to reports retroactively.

How do I set up an AI channel in GA4, step by step?

These steps follow Google's custom channel groups help page as of October 2026. You need the Editor role or above on the property.

1. 01

   Open Channel groups

   Go to Admin, then under Data display, click Channel groups.

2. 02

   Create a group from the default

   Click Create new channel group. GA4 starts you with a copy of the default group, so the AI Assistant channel is already in the list. Name it something your team will recognize, such as "Channels with AI".

3. 03

   Add the AI channel

   Click Add new channel and name it, for example "AI (all referrers)". Click + Add condition group, choose Source as the dimension, select matches regex, and paste the pattern above. Click Save channel. Google notes channel definitions aren't case sensitive.

4. 04

   Move it above Referral

   Click Reorder, drag the new channel above Referral, and click Apply. Order matters because a session goes to the first channel it matches. If the AI channel sits below Referral, Referral takes the traffic first. Google's own AI example gives the same instruction.

5. 05

   Decide where it sits relative to AI Assistant

   Above AI Assistant gives you one combined AI line. Below it keeps Google's channel intact, and your channel shows only what Google missed. The next section helps you choose.

6. 06

   Save and check the report

   Click Save group. Then go to Reports, Acquisition > Traffic acquisition, and select your new group as the primary dimension. Add Session source as a secondary dimension to see which assistants are in it.

7. 07

   Book the quarterly review

   Put a recurring date in the calendar to read the channel's top sources, add new assistants and prune false positives. Note every change to the pattern, with its date, in the report itself.

Should the custom channel sit above or below GA4's AI Assistant channel?

Both work. They answer different questions.

If you're unsure, start below AI Assistant for a quarter. The second line shows how much Google's list misses for your traffic. If it's small, the built-in channel is enough. If it's large, move your channel to the top and report one line.

Which method should I use: the built-in channel, a regex channel or Source group?

There are three ways to see AI referrals in GA4 in October 2026, and most stores will use all three: the built-in channel as a check, a custom channel for reporting, and Source group for history.

What about sales that close inside the AI assistant?

Some AI channels can take the order without sending the shopper to your site. For Shopify stores, Shopify's help center says Google Analytics and custom pixels won't fire in the direct checkout inside Microsoft Copilot, or inside Google AI Mode and Gemini. Only server-to-server pixels fire, for checkout started and checkout completed. Those orders never become GA4 sessions, so no channel rule can count them.

ChatGPT works differently for Shopify merchants. Shopify's agentic storefronts send the ChatGPT shopper to your own online store checkout, in ChatGPT's in-app browser or a new tab, so the visit does reach your site. Whether that visit carries a referrer GA4 recognizes is something to check in your own data. How to track ChatGPT traffic and revenue on Shopify walks through that check, and the AI shopping channels guide maps where the sale closes on each channel.

How should I report AI traffic once it's split out?

Report the counted layers as numbers and the estimated layers as notes. A monthly AI line that mixes a GA4 count with a guess about Direct can't be audited.

• AI sessions and AI share of sessions from your custom channel, with the date of the last regex change.
• AI key events, AI purchase revenue and AI conversion rate against the site average, from the same channel. Whether AI traffic converts better is still an open question, so measure your own rather than borrowing a benchmark.
• AI revenue per session, which keeps a small channel's revenue in proportion.
• A standing caveat that Organic Search includes AI Overviews and AI Mode, and that Direct includes some AI visits GA4 can't identify.
• Orders from in-chat checkouts, counted from Shopify's Agentic reports and shown on their own line, never added into the GA4 total.

The monthly AI-attributed revenue report walks through each of those rows, how to read month-over-month moves, and what to say when the number is small.