Control GPTBot, PerplexityBot & Google-Extended — allow crawling or block?

AI Crawlers at a Glance: GPTBot, PerplexityBot, and Google-Extended

Whether you should block AI crawlers like GPTBot, PerplexityBot, or ClaudeBot depends on a central strategic decision: If you want to be cited as a source in generative AI answers, you must grant access to search bots. If, on the other hand, you prioritize the strict protection of your raw data from being used to train large language models (LLMs), then a targeted exclusion via robots.txt is the right approach. The digital landscape has evolved from a purely Google-centric one to a multi-engine ecosystem where various automated systems collect, evaluate, and process information.

To make an informed decision, it is important to understand the different types of web crawlers and their specific tasks. Not every bot operated by an AI company serves the same purpose. Fundamentally, a distinction can be made between crawlers for model training and crawlers for real-time search.

Training vs. Real-Time Search: The Key Players

GPTBot is a web crawler operated by OpenAI. Its primary function is to collect publicly accessible content from the web to expand the training database for future large language models (Source: OpenAI documentation on web crawlers). When this bot crawls your site, the data flows into the fundamental knowledge of the models. A direct link to your website is generally not created as a result.

The situation is different with OAI-SearchBot. This crawler is used by OpenAI to retrieve real-time information for search queries in ChatGPT Search. When a user asks a current question, the system searches for suitable live sources. If you block OAI-SearchBot, you exclude your website as a direct, cited source for current ChatGPT answers. In addition, ChatGPT Search relies on third-party search partners such as Bing, depending on the query. Blocking Bingbot can therefore also reduce visibility in ChatGPT.

PerplexityBot functions similarly to OAI-SearchBot. It retrieves URLs to use them as context for the answers of the AI search engine Perplexity (Source: Perplexity AI documentation on PerplexityBot). Here, too, the rule applies: those who block the bot will not be linked as a source in Perplexity's answers.

The Special Role of Google-Extended

A common misunderstanding concerns Google-Extended. This is not a classic web crawler, but a control token for robots.txt. With the entry "Google-Extended," you prohibit Google from using your content for training generative AI models like Gemini (Source: Google Search Central Blog, article on Google-Extended).

Important for search engine optimization: Blocking Google-Extended has no impact on your visibility in Google AI Overviews (formerly SGE) or classic Google Search. The regular Googlebot is still responsible for indexing and displaying in AI Overviews. AI Overviews use different models and link sets to summarize search results. If you want to be considered as a source in Google AI Overviews, you must allow Googlebot to crawl and provide helpful, indexable content.

Why Blocking AI Crawlers Can Cost Reach

The decision to universally block AI crawlers can have far-reaching implications for a company's digital presence. Many AI search systems today work with retrieval mechanisms that specifically fetch sources, evaluate text passages, and use them as context for the generated answer in response to a user query. This process is often summarized under the term Generative Engine Optimization (GEO).

If you block bots like OAI-SearchBot or PerplexityBot, you deny these systems the ability to check your content in real time. As a result, the probability of your website being cited as a source for current search queries on these platforms drops to zero.

Visibility in the Multi-Engine Ecosystem

Information retrieval is increasingly shifting. Users no longer search exclusively via classic Google Search but use Perplexity, ChatGPT, Claude, or voice assistants. A study on Generative Engine Optimization shows that content with clear facts, statistics, and an easily graspable structure is more readily considered as a source by AI systems (Source: Princeton University, study on Generative Engine Optimization).

Those who block their content from these systems leave the field open to the competition. If a user searches in ChatGPT for the best software solutions for a specific problem and your website blocks OAI-SearchBot, the AI will resort to the sites of your competitors who allow crawling. Presence in AI answers is therefore a relevant factor for brand awareness and future referral traffic.

Traffic Forecasts and Strategic Positioning

Analysts assume that search behavior will continue to change in the coming years. One forecast suggests that traditional search engine volume could decrease by up to 25 percent by 2026 as users increasingly turn to AI chatbots and virtual agents.

For website operators, this means that a sole focus on classic SEO metrics is no longer sufficient. The strategic consideration should be: How can my content be prepared so that it is understood and cited by various engines? Allowing the relevant search bots is the basic technical prerequisite for this.

Before-and-After Example

For AI systems to classify and cite a text as a relevant source, it must be precise, contextually strong, and understandable without prior knowledge. Vague formulations are often ignored by retrieval mechanisms.

Before (Weak Passage, little context for AI systems):
We offer great solutions for blocking bots. You simply enter the name into the file and save it. This helps against data theft and protects the website from unwanted access. Many find this very useful for their daily work.

After (Optimized Passage, increases the likelihood of being considered as a source):
To block OpenAI's GPTBot, website operators adjust the robots.txt file in the root directory. By using the instruction "User-agent: GPTBot" followed by "Disallow: /", the crawler is prohibited from reading website content for training language models. For real-time search in ChatGPT, however, the OAI-SearchBot must be considered and controlled separately.

Technical Implementation: How to Control Crawlers via robots.txt

The control of web crawlers primarily takes place via the robots.txt file. This text file is located in the root directory of your domain and gives bots instructions on which directories or URLs they are allowed to access and which they are not. Reputable AI crawlers strictly respect these guidelines.

It is important to formulate the instructions precisely to avoid accidentally blocking bots that are essential for your visibility. A blanket blocking of all bots via a wildcard entry is rarely advisable.

Blocking or Allowing Specific Bots

If you want to prevent your content from being used for training OpenAI's models, add the following code block to your robots.txt:

User-agent: GPTBot
Disallow: /

If you also want ChatGPT Search to be able to cite your page as a live source, you must ensure that OAI-SearchBot is not blocked. Since bots are allowed to crawl everything by default that is not explicitly forbidden, it is sufficient not to list OAI-SearchBot in the Disallow list. To be absolutely sure, you can explicitly allow it:

User-agent: OAI-SearchBot
Allow: /

For exclusion from Google training (without affecting Google Search or AI Overviews), you use the Google-Extended token:

User-agent: Google-Extended
Disallow: /

Logfile Analysis as a Technical Early Indicator

To check which bots are actually accessing your website, regular logfile analysis is recommended. Server logs show you exactly which user agent accessed which URL and when. Accesses from AI bots are a technical early indicator that your page is accessible and being crawled by the systems.

Important for classification: A bot access in the logfile is not a guarantee that your content will be cited in an AI answer. It merely proves that technical accessibility is given. Whether the content is ultimately used depends on its relevance, structure, and the specific user query. Therefore, logfile data should always be considered in combination with citation monitoring and referral traffic analyses.

Optimizing Content for AI Systems: Structure and Relevance

If you have decided to allow AI crawlers, the question arises: How do you prepare your content so that it is more easily considered as a source by these systems? AI systems look for clear answers, strong entities, and a logical document structure.

The first step is to understand the actual needs of the target audience. Before writing a text, you should identify relevant user questions from SERP data. SEOlyze supports you in this by aggregating and clearly presenting the most common questions and search intentions of the target audience. This ensures that your text answers exactly the questions that are also asked of AI systems.

Semantic Depth and Entities

Many AI systems evaluate the thematic depth of a document to assess its expertise. A text that only superficially touches on a topic is less likely to be cited than a comprehensive guide. To ensure that all important entities and technical terms are covered, you can use the competitive comparison in SEOlyze. This feature shows you missing terms compared to the top results and helps you close content gaps.

Structure also plays a crucial role. A logical outline with descriptive headings (H2, H3) makes it easier for crawlers to grasp the context of individual paragraphs. With SEOlyze, the structure and outline can be planned data-driven in advance. If you have initial text passages generated or write them yourself, it is also advisable to score and enhance this AI draft in SEOlyze to objectively check the content substance before publication.

Structured Data as a Foundation

Structured data (Schema.org) is not a deterministic silver bullet that guarantees a citation. However, it forms a strong foundation because it makes information machine-readable and easier to verify. For guides and editorial content, the Article or BlogPosting markup is recommended (Source: Schema.org specifications for Article and BlogPosting).

A note on FAQPage: Even if FAQ rich results in Google Search no longer serve as a primary lever for prominent snippets for most pages, the schema markup is by no means outdated. It continues to help search engines and AI systems clearly identify question-answer combinations in the text. It is important that the visible FAQ content is cleanly integrated into the main text. For Google AI Overviews, by the way, there is no special schema markup; here, primarily indexable, visible, and helpful content counts (Source: Google Search Central, documentation on AI Overviews).

Test SEOlyze to optimize your content data-driven for search engines and AI systems and to make your editorial processes more efficient.

Risks and Trade-offs: Data Sovereignty vs. AI Visibility

Despite the potential reach advantages, there are legitimate reasons to block AI crawlers. The decision is often a trade-off between visibility in new channels and the protection of one's own intellectual property.

A central risk is that AI systems may reproduce or heavily paraphrase content without adequately referencing the original source. This can lead to so-called zero-click searches, where the user receives their answer directly in the chat interface and no longer has a reason to visit the actual website. For business models heavily dependent on display advertising or direct traffic, this can lead to revenue losses.

Copyright and Commercialization

Another aspect is data sovereignty. If GPTBot uses your content for training models, your hard-earned information flows into a commercial product of a third-party provider without you being directly compensated for it. Many publishers and content creators view this critically and consistently block training bots to strengthen their negotiating position for potential licensing agreements.

Some AI providers are responding to these concerns. There are initiatives where publishers are involved in advertising revenue if their content is cited in AI answers. An example of this is Perplexity's Publisher Program, which promises revenue sharing for verified partners. Such developments show that the ecosystem is still in an early phase of discovery.

Regular Review of the Strategy

The digital landscape is highly dynamic. A decision that is correct today may be outdated in six months. Website operators should therefore not view their robots.txt configuration as a static document. It is advisable to closely monitor developments in AI search, evaluate your own referral data, and adjust the strategy as needed.

Those who decide to allow crawlers should focus on building a strong brand and creating content that goes beyond mere factual information. Original opinions, proprietary data, expert interviews, and deep analyses are harder for an AI to replace and offer users real added value that justifies clicking on the website.

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