Google Tests URL Tracking in AI Overviews

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Glowing chain links and a Chrome puzzle piece symbolizing AI overview tracking by Google

By NewSunSEO October 5, 2026

Site owners who want to see exactly which clicks come from Google AI Overviews and which come from the standard web results may soon get that answer in their analytics. Links inside AI Overviews and AI Mode are being spotted with an appended parameter that tags the source, giving a clearer read on AI-driven traffic.

The behavior was first noticed on a number of link URLs that carried ?st_source=ai_overview at the end, including links in the citation list that AI Overviews show beneath their generated answers. If the behavior rolls out broadly, anyone running analytics can finally separate a click that arrived through the AI summary from a click that came through the regular blue-link results below it.

What the parameter looks like

The parameter in question is ?st_source=ai_overview, and it appears on the destination URL rather than on the Google domain. The same parameter has been seen on links inside AI Mode, the conversational search experience, not only on the inline citations inside an AI Overview.

In practice this means a server access log or a referral report could show requests with that exact query string attached, which makes it possible to filter and count visits that originated from an AI surface in Google Search.

What this would tell site owners

Until now, traffic from AI Overviews has been hard to separate from regular Google Search traffic. Both arrive as direct or unbranded visits, and the only hint is the page itself, which is often not a clean landing page. A dedicated parameter gives three concrete gains:

It pinpoints when a visit came from an AI Overview or AI Mode, not from the ten blue links below it.
It lets analytics filters segment AI-referred sessions, so conversion rate, bounce rate, and engagement can be compared side by side with standard organic traffic.
It shows which pages AI Overviews cite most often, which pages get the most AI-driven clicks, and which topics drive the largest share of AI traffic.

For publishers and SEO teams uncertain about the value of AI Overview visibility, that level of clarity is the main appeal.

Was this really Google?

The observation did not reproduce in several other browsers when tested, and a follow-up explanation pointed to a different source: a Chrome browser extension that was rewriting link URLs inside AI Overviews and AI Mode to include the parameter, then passing the rewritten traffic on, likely to data brokers.

That explanation matters because the same symptoms can come from two very different places. If the parameter comes from a user-side extension, any site that sees it in its logs has a visitor with that extension installed, not a Google-driven AI Overview click. If the parameter comes from Google itself, every visitor who clicks an AI Overview link will carry the tag.

Until Google confirms or denies the behavior at the search level, anyone seeing the parameter in their logs should treat it as a signal worth investigating rather than a confirmed Google rollout.

How to check whether the parameter is real in your own data

A few practical checks can separate a Google-issued parameter from a browser extension artifact.

Open an AI Overview in a clean browser profile with no extensions, and inspect the link target before clicking. If ?st_source=ai_overview is already on the URL before the click, the source is Google. If it appears only after the click, an extension is rewriting the link in flight.
Compare server logs across visits. A Google-issued parameter will show on every AI Overview visit from a given query. An extension-only parameter will only show on visitors who have the extension installed.
Check the referrer header on the resulting request. AI Overview clicks from Google typically carry a referrer from google.com. Extension-rewritten links can carry any referrer or none at all.

For teams that already run a technical audit on their site, behavior like this is a useful reason to revisit the audit checklist: link rewriting, query parameter handling, and referrer headers all sit inside a standard technical SEO review. SEOScanPRO’s technical audit walks through each of these checks and shows the measured result behind them.

Why Google would want to add the parameter itself

From Google’s side, tagging AI Overview links at the source would be a small but useful move. It would let the company measure click-through rate from AI Overviews separately from regular results, which in turn would help tune how often AI Overviews appear, how many citations they show, and which kinds of queries they answer. The same data would also be valuable to the publishers whose pages are being linked, and to advertisers who want to understand the path a user took before converting.

It is also the kind of change Google has made before on other surfaces. Regular search ads have carried gclid for years, and many other Google products append their own parameters to outbound links. Adding a parameter to AI Overview links would follow that same pattern.

What to watch next

The key open question is whether Google is actually testing this at the search level, or whether every reported sighting so far is from a browser extension rewriting the URL. Until Google comments, anyone analyzing AI Overview traffic should log sightings of the parameter, note the browser and extension setup of the visitor, and report back when more is known.

For now, the practical step is to instrument analytics to recognize ?st_source=ai_overview as its own channel, so that the moment the behavior does roll out, the data is already clean and segmented.

FAQ

What is the ?st_source=ai_overview parameter?

It is a query string that has been seen appended to the end of link URLs inside Google AI Overviews and AI Mode. Its purpose is to mark the link as having come from an AI surface in Google Search.

Is Google really adding this parameter to AI Overview links?

That is not confirmed. The original sightings were not reproducible across other browsers, and a follow-up pointed to a Chrome browser extension rewriting the URLs rather than Google itself.

How can site owners tell real AI Overview traffic from extension noise?

Test in a clean browser with no extensions and inspect the link before clicking, compare server logs across many visitors to see if the parameter is universal or rare, and check the referrer header on the resulting request.

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