Blocking AI Training Is Not the Same as Blocking AI Search

When website owners decide whether to allow AI crawlers, the discussion often starts with a deceptively simple question: should AI systems be allowed to access the website?

But this question hides an important distinction. Not every crawler accesses content for the same reason.

Some crawlers collect information that may be used to train or improve models. Others discover pages that can be retrieved in response to a user’s search query. These activities are related, but they are not interchangeable.

And blocking one does not automatically mean blocking the other.

Training and search are different processes

A language model’s training data and the information retrieved during a live search belong to different stages of how AI systems work.

Training involves collecting and processing data that may contribute to the development of a model. Once a model has been trained, its stored parameters are not a live index of every website it encountered.

Search-based systems work differently. When someone asks a question, the system may retrieve current information from external sources, process relevant pages and use them to construct an answer. This is commonly described as retrieval-augmented generation or search-grounded generation.

A website can therefore be excluded from certain training-related data collection while remaining available for real-time search retrieval.

The reverse distinction matters too: allowing a training crawler does not guarantee that a website will be discovered, retrieved or cited in a search response.

The distinction exists in actual crawler configurations

This is not merely a theoretical difference. Major AI platforms document separate crawler identities and purposes.

OpenAI distinguishes between GPTBot, associated with collecting content that may be used to train generative AI models, and OAI-SearchBot, which is used to surface websites in ChatGPT search.1

Google distinguishes Google-Extended, a control related to the use of content for certain AI training and grounding purposes, from Googlebot, which crawls websites for Google Search. Google explicitly states that Google-Extended does not affect inclusion in Google Search.2

Perplexity documents its own PerplexityBot for search-related crawling and describes how it interacts with robots.txt.3 Its search infrastructure can also involve third-party crawlers.4

The implementation differs between providers, but the underlying lesson is consistent: crawler access needs to be considered according to its purpose, not treated as one universal permission.

What happens when you block the wrong crawler?

Imagine a publisher who wants to prevent their articles from being used for model training but still wants those articles to appear as sources in AI-generated search answers.

If that publisher blocks every bot associated with AI companies without checking what each one does, they may unintentionally restrict access needed for search discovery.

The result is not necessarily an immediate disappearance from every AI product. Some systems can discover URLs through alternative sources or retrieve pages through other infrastructure. But blocking a relevant search crawler can impair the system’s ability to access the page’s full content.

That matters because technical accessibility is one of the basic conditions for a page to be used by search-grounded AI systems.

It is not a guarantee of visibility. It is a prerequisite for certain forms of visibility.

What website owners should check

Before changing crawler permissions, identify what each crawler actually does.

GPTBot

Review its role in OpenAI’s model-training data collection.

OAI-SearchBot

Review whether you want to allow ChatGPT search discovery.

Googlebot

Check that Google Search crawling remains available if you want eligibility for Google’s AI search features.5

Google-Extended

Understand its separate role in Google’s AI-related data use.

PerplexityBot

Review its search-crawling purpose and documented robots.txt behaviour.

Do not assume that blocking a training-related crawler blocks search, or that allowing a search crawler grants permission for every other use of your content.

Also remember that robots.txt is a crawler instruction mechanism, not an access-control or security system. It does not prevent every possible third party from accessing a publicly available page.

Visibility begins before optimisation

GEO and AEO discussions often focus on how content should be written: its structure, factual clarity, use of sources, entity references and other characteristics that might make it useful to generative search systems.

Those questions matter, but they come after a more basic one.

Can the system access the information in the first place?

A page can be exceptionally well written, carefully structured and full of useful information. None of those qualities can compensate for a crawler being unable to retrieve its content through the relevant discovery channel.

This does not mean website owners should allow every crawler unrestricted access. Decisions about training, search discovery, licensing and data use are legitimate and separate considerations.

It means those decisions should be made deliberately.

Before optimising a website for AI search, understand which AI systems are allowed to find it, which are allowed to use it, and for what purpose.

Because blocking AI training and blocking AI search are not the same decision.