Understanding Google-Extended: AI Training Crawler Guide
Learn about Google-Extended, the AI crawler for Gemini and Vertex AI. How to block it in robots.txt and distinguish it from Googlebot.
What is Google-Extended
Google-Extended is a web crawler that Google utilizes specifically for AI training purposes, collecting data from websites to enhance Google’s AI models like Gemini and Vertex AI. This crawler functions separately from the standard Googlebot, which indexes pages for Google Search.
Web crawlers like Google-Extended are crucial because AI models require massive amounts of text data for training, as detailed in Google’s crawling infrastructure. Companies deploy these bots to gather publicly available content from across the web. For website owners and developers, understanding these crawlers is important because you can control whether your content is used for AI training.
The primary feature of Google-Extended is that it operates independently of search indexing. You can block Google-Extended using the robots.txt file without affecting your site’s visibility in Google Search results. This grants webmasters more control over how their content is utilized. Google launched this crawler to provide transparency and choice to content creators who may not want their work used for AI training purposes.
Why Google-Extended Exists
Google developed Google-Extended to separate AI training activities from search indexing duties. Prior to this crawler, Googlebot conducted both tasks, leaving website owners with no option to opt out of AI training without also removing their sites from Google Search.
The objective is simple. Google needs training data for its AI products. Gemini, Google’s conversational AI, requires billions of text examples to generate human-like responses. Similarly, Vertex AI, Google’s machine learning platform, benefits from diverse training datasets. Licensing all this content or creating it from scratch is impractical, so Google resorts to AI web scraping of publicly available content.
This practice has raised concerns among content creators and publishers. Many sites prefer appearing in search results but don’t want their content feeding AI models. Some publishers argue that their content holds commercial value beyond search indexing. In response to these concerns, Google introduced Google-Extended as a separate user-agent, allowing site owners to make independent choices about search visibility versus AI training participation.
How Google-Extended Works
Google-Extended operates much like other web crawlers. It sends requests to web servers, downloads HTML content, and processes the text. The crawler identifies itself through a specific user-agent string in its HTTP requests.
The user-agent token for Google-Extended is:
Google-Extended vs Googlebot Separation:
Google-ExtendedWhen the crawler visits your site, your server logs will display this identifier. This helps you monitor whether Google-Extended is accessing your content. The crawler respects standard robots.txt directives, which means you can block it the same way you’d block any other bot.
Google uses the collected data to train and improve its AI models. The content is processed, analyzed, and incorporated into training datasets. Unlike search indexing, where Google stores and serves your content directly, AI training involves extracting patterns and information that help models generate new content.
Website owners should note that Google-Extended follows robots.txt rules. If you disallow it, the crawler should stop accessing your site for AI training purposes. However, blocking Google-Extended does not prevent Google from using content it collected before you added the block.
Blocking Google-Extended in Robots.txt
Blocking Google-Extended is straightforward. You add specific directives to your robots.txt file, which resides in your website’s root directory and instructs crawlers on which parts of your site they can access.
To block Google-Extended entirely, add the following lines to your robots.txt:
User-agent: Google-Extended
Disallow: /The first line specifies which crawler the rules apply to. The second line tells it not to crawl any part of your site. The forward slash signifies everything from the root directory down.
If you want to block only specific sections, modify the Disallow path:
User-agent: Google-Extended
Disallow: /blog/
Disallow: /articles/This blocks your blog and articles directories but allows the crawler to access other areas.
You can also block multiple AI crawlers at once. Here’s how to block both Google-Extended and another common AI crawler:
User-agent: Google-Extended
Disallow: /
User-agent: GPTBot
Disallow: /After updating robots.txt, verify that the file is accessible at yoursite.com/robots.txt. The changes take effect immediately, though it may take time for crawlers to see and respect the new rules. Google provides documentation on robots.txt formatting in their Search Central documentation if you need more detailed guidance.
Google-Extended vs Googlebot
Understanding the difference between Google-Extended and Googlebot is crucial for website owners since these two crawlers serve different purposes.
- Googlebot crawls the web to index content for Google Search. When you perform a search on Google, the results are drawn from Googlebot’s index. Blocking Googlebot removes your site from Google Search results, affecting your site’s discoverability and traffic.
Crawler Blocking Process:
- Google-Extended crawls the web specifically for AI training, feeding data to Gemini and Vertex AI. Blocking Google-Extended does not affect your search rankings or visibility. Your site still appears in Google Search results as usual.
Here’s a comparison:
| Feature | Googlebot | Google-Extended |
|---|---|---|
| Purpose | Search indexing | AI training |
| Affects search rankings | Yes | No |
| User-agent | Googlebot | Google-Extended |
| Can be blocked separately | Yes | Yes |
| Launched | 1996 | 2023 |
You can block one, both, or neither, depending on your needs. Many sites block Google-Extended while allowing Googlebot. This maintains search visibility while opting out of AI training.
The robots.txt directives work independently:
User-agent: Googlebot
Disallow: /private/
User-agent: Google-Extended
Disallow: /
Google Crawler Comparison:
This example blocks Google-Extended from everything but only blocks Googlebot from the private directory.
Comparing AI Crawlers
Google-Extended isn’t the only AI training crawler out there. Several companies deploy similar bots to gather training data, so understanding the landscape helps you make informed decisions about which crawlers to allow.
Here’s a comparison of major AI crawlers:
| Crawler | Company | Purpose | User-Agent Token | Launched |
|---|---|---|---|---|
| Google-Extended | Gemini and Vertex AI training | Google-Extended | 2023 | |
| GPTBot | OpenAI | ChatGPT and GPT model training | GPTBot | 2023 |
| CCBot | Common Crawl | Dataset for various AI researchers | CCBot | 2011 |
| anthropic-ai | Anthropic | Claude AI training | anthropic-ai | 2023 |
| ClaudeBot | Anthropic | Claude AI training | N/A | N/A |
Each crawler serves a specific company’s AI products. GPTBot collects data for OpenAI’s language models. CCBot creates the Common Crawl dataset used by many AI researchers. Anthropic runs multiple crawlers for Claude.
Blocking strategies vary by website. News publishers often block all AI crawlers to protect their content’s commercial value. Personal blogs might allow some crawlers but not others. E-commerce sites typically focus on blocking crawlers from accessing product descriptions and reviews.
To block multiple AI crawlers, add separate directives:
User-agent: Google-Extended
Disallow: /
User-agent: GPTBot
Disallow: /
User-agent: CCBot
Disallow: /Some webmasters create a group blocking strategy; however, robots.txt doesn’t support grouping directly, so separate entries are needed for each user-agent.
Official Documentation and Resources
Google provides official documentation about Google-Extended. The primary resource is Google Search Central, where Google publishes guidelines for webmasters and developers.
You can find information about Google-Extended in the Google Search Central documentation. The docs explain the crawler’s purpose, how to identify it in server logs, and blocking methods. Google updates this documentation as policies evolve.
For robots.txt syntax and best practices, consult the robots.txt specifications. Google Search Central includes a robots.txt guide that covers formatting, common mistakes, and testing tools. The robots.txt tester in Google Search Console helps verify that your directives work correctly.
Key resources include:
- Google Search Central Help Community for asking questions
- Robots.txt specifications at robotstxt.org for technical details
- Google’s official blog for announcements about crawler changes
- Server log analysis tools to monitor which crawlers access your site
Webmasters should regularly check Google’s official channels for updates. AI crawler policies evolve as the technology and legal landscape change. What’s allowed today might require different handling tomorrow.
If you’re managing multiple sites, consider creating a standard robots.txt template to ensure consistent AI crawler blocking across your properties. Document your choices so team members understand why certain crawlers are blocked.
Privacy and Data Usage Considerations
When you permit Google-Extended to crawl your site, your content becomes part of Google’s AI training datasets. This has implications for privacy, copyright, and data usage.
Google’s AI models learn patterns from the text they’re trained on. Your content doesn’t get stored verbatim in most cases, but the models learn from it. This means phrases, facts, writing styles, and information from your site can influence how Gemini responds to users.
For sites with user-generated content, this raises questions. Comments, forum posts, and reviews might contain personal information. While publicly visible, users may not expect their words to train AI models. Some sites add privacy notices explaining that public content might be crawled for AI training.
Commercial considerations also matter. Publishers invest in creating quality content. When AI models train on this content and then generate similar information, it potentially reduces the original content’s value. This is why many news sites and content platforms block AI crawlers.
If you decide to block Google-Extended, document this decision. Add a comment in your robots.txt explaining the rationale:
# Blocking AI training crawlers to protect user privacy and content value
User-agent: Google-Extended
Disallow: /Review your decision periodically. AI companies sometimes offer compensation or partnership programs for training data. Google might introduce options beyond simple blocking or allowing in the future.
Technical Implementation Tips
Implementing Google-Extended blocking requires careful attention to technical details. Small mistakes in robots.txt can accidentally block crawlers you want to allow or fail to block those you aim to stop.
First, verify your robots.txt file is properly formatted. Syntax errors can cause the entire file to be ignored. Use a robots.txt validator to check for issues. The file must be plain text, not HTML or another format.
Location is important. The robots.txt file must be at your domain’s root:
- Correct: example.com/robots.txt
- Incorrect: example.com/blog/robots.txt
- Incorrect: example.com/files/robots.txt
Subdomains require their own robots.txt files. If you have blog.example.com, create a separate robots.txt there.
Case sensitivity applies to paths, but not user-agent names. These are equivalent:
User-agent: Google-Extended
User-agent: google-extended
User-agent: GOOGLE-EXTENDEDBut these paths are different:
Disallow: /Blog/
Disallow: /blog/Test your robots.txt before deployment. Visit it in a browser to confirm it’s accessible. Check for typos in the user-agent name. A misspelled “Google-Extended” won’t block anything.
Monitor your server logs after implementing blocks. Look for the Google-Extended user-agent in access logs. If you still see it after blocking, investigate whether your robots.txt is being read correctly.
For content management systems like WordPress, some plugins manage robots.txt. Ensure your manual edits do not conflict with plugin settings. Some hosting providers also inject robots.txt rules that might override yours.
Impact on SEO and Site Performance
Blocking Google-Extended has minimal impact on traditional SEO. Your search rankings remain unchanged because the crawler doesn’t affect indexing, but indirect considerations exist.
Server load slightly decreases when you block crawlers. Fewer bot requests mean less bandwidth usage and processing. For high-traffic sites, blocking multiple AI crawlers can reduce costs. The impact is usually small unless you’re dealing with aggressive crawling patterns.
SEO strategy might evolve as AI becomes more important for discovery. Google’s AI Overviews and SGE (Search Generative Experience) currently use different systems than Google-Extended. Blocking the AI training crawler doesn’t affect these search features today, but future combination is possible.
Some SEO professionals debate whether participating in AI training provides indirect benefits. The theory suggests that if your content trains Google’s AI well, the AI might reference or recommend your site more often. This remains speculative, with no confirmed evidence showing that allowing Google-Extended improves rankings or AI-generated recommendations.
Content distribution strategies should consider AI crawlers. If you syndicate content across multiple domains, decide whether to block AI crawlers on all properties or just primary ones. Some sites permit crawling on older content while blocking newer premium articles.
From a performance perspective, robots.txt adds negligible overhead. The file is small and cached by crawlers. Adding Google-Extended blocks doesn’t slow down your site or create technical issues.
Conclusion
Google-Extended is Google’s dedicated crawler for AI training purposes, collecting web content to train Gemini and Vertex AI models. Unlike Googlebot, which handles search indexing, Google-Extended focuses solely on gathering training data. Website owners can block this crawler without affecting their Google Search visibility.
Blocking Google-Extended involves adding simple directives to your robots.txt file. The process is straightforward and takes only minutes to implement. You maintain full control over whether your content participates in AI training, aligning with your privacy policies, content strategy, and business goals.
The landscape of AI crawlers continues expanding. Google-Extended joins GPTBot, CCBot, and other similar crawlers in requesting access to web content. Understanding these tools helps you make informed choices about your content’s usage. Regular monitoring and policy updates ensure your preferences are respected as technology evolves.
Frequently Asked Questions
What type of content can Google-Extended access?
Google-Extended can access publicly available content from websites that do not block it through their `robots.txt` file. This includes text, images, and other forms of web content that are not restricted by any directives.
How can I check if Google-Extended has crawled my site?
You can monitor your server logs to see if requests are made by the Google-Extended user-agent. Look for entries that include the token "Google-Extended" in the user-agent string to confirm its activity on your website.
Will blocking Google-Extended affect my website's visibility in search results?
No, blocking Google-Extended will not affect your site's visibility or ranking in Google Search results. Googlebot and Google-Extended operate independently, so you can choose to block one without impacting the other.
Can I selectively block certain parts of my site from Google-Extended?
Yes, you can specify which parts of your site to block from Google-Extended in your `robots.txt` file. Use the `Disallow` directive to restrict access to specific directories or pages while allowing others.
What happens to my content if I block Google-Extended?
If you block Google-Extended, it will stop accessing your content moving forward. However, content that was previously accessed can still be used for training AI models, as blocking does not retroactively apply to data already collected.
Are there any legal implications of allowing Google-Extended to crawl my content?
Allowing Google-Extended to crawl your content may raise questions regarding copyright and data usage, especially if user-generated content is involved. It's advisable to review your site's privacy policy and consider informing users about the potential use of their contributions for AI training.
How often does Google-Extended visit websites?
The frequency of Google-Extended's visits can vary based on numerous factors, including site popularity and the volume of new content. Like other crawlers, it operates on a schedule that may change over time as content and data needs evolve.
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