Traffic from AI tools (ChatGPT, Perplexity, Gemini, Claude, etc.) is one of the fastest-growing source categories for many publishers. Piano Analytics has progressively added support for this traffic type.
The automatic “Generative AI” source
Piano Analytics now recognizes a dedicated "Generative AI" organic source. When a visitor arrives at your site from an AI chatbot or LLM platform that Piano can identify, the visit is automatically classified under this source.
The Generative AI source is one of the six standard organic source categories, alongside Direct Access, Webmails, Social media, Search engines, Portal sites, and Referrer sites. It appears in the same reporting interfaces as the other organic sources, with no special configuration needed once your tagging is in place.
The list of recognized AI platforms is maintained by Piano and updated as new tools emerge. Common entries include:
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ChatGPT (OpenAI)
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Perplexity
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Gemini (Google)
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Claude (Anthropic)
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Microsoft Copilot
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etc.
The full list is visible in Data Management > Sources > Sources lists > Generative IA.
Detection methods
A visit is classified as Generative AI when either of two signals identifies a recognized AI platform:
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Referrer. The visitor arrives with a referrer that belongs to a recognized AI platform. This is the original detection method.
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utm_source query parameter. The landing URL carries a
utm_sourceparameter whose value matches Piano's maintained list of values unique to AI apps, for examplechatgpt.com,perplexity,copilot.com, oropenai. This method has been active since August 5, 2026, so it applies to visits collected from that date onward.
In both cases, the visit is classified under the Generative AI source, and the specific platform behind it is recorded as the source detail.
Because the utm_source parameter travels in the landing URL itself rather than in the referrer header, this second method also catches visits where the referrer is missing or stripped.
Retroactive classification
When Piano Analytics adds a new AI source to its recognized list, visits collected before the addition still bear the previous classification (typically Direct Access or Referrer Sites).
If you need consistent historical classification before and after a platform was added:
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Use a source group (see Source groups) that combines the "old" classification (typically a referrer-site match for the AI domain) with the "new" Generative AI source.
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Apply the source group to your reports for a unified view across the boundary.
The no-referrer limitation
Not every AI tool sends a referrer header when its users click through to your site. Many AI tools use no-referrer or strip the referrer through their own URL redirect, which means:
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The browser arrives at your site without any referrer information.
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If the URL also carries no recognized
utm_source, Piano Analytics has no signal to identify the platform. -
In that case, the visit is classified as Direct Access (out of site), not as Generative AI.
The utm_source match now closes part of this gap. When an AI tool appends a recognized utm_source value to its outbound links, Piano classifies the visit as Generative AI even though no referrer was sent. A visit only falls into Direct Access when it arrives with neither a referrer nor a recognized utm_source.
This is especially relevant for ChatGPT. Many ChatGPT visits historically arrived as Direct Access because the referrer was stripped. Where ChatGPT appends a recognized utm_source (such as chatgpt.com), those visits are now classified as Generative AI. Visits that carry neither signal still land in Direct Access.