A new generation of web crawlers is visiting your site—not from search engines, but from AI companies training models and powering answer engines. These crawlers raise important questions about control, attribution, and the future of web content.
Understanding who's crawling your content, why, and how to control access through robots.txt has become a critical part of modern content strategy. The decisions you make today will shape how AI systems interact with your content for years to come.
The New Landscape of AI Crawlers
Traditional web crawlers from Google, Bing, and other search engines have been crawling the web for decades. AI crawlers serve different purposes:
Training Crawlers
These crawlers collect vast amounts of web content to train large language models. Examples include:
- GPTBot: OpenAI's crawler for training GPT models
- Google-Extended: Google's crawler for training AI models (separate from search indexing)
- ClaudeBot: Anthropic's crawler for training Claude models
- CCBot: Common Crawl's bot, whose data is used by many AI companies
These crawlers typically operate on a large scale, downloading billions of pages to build training datasets.
Retrieval Crawlers (RAG)
These crawlers access content in real-time to power answer engines. Unlike training crawlers that collect data for static datasets, retrieval crawlers fetch fresh information on-demand to generate current, cited responses.
Examples include crawlers from Perplexity, You.com, and similar AI answer engines that retrieve and cite content dynamically.
Understanding Robots.txt for AI Crawlers
Robots.txt is a file placed at your website's root that tells crawlers which parts of your site they can and cannot access. With AI crawlers, this file has gained new importance.
Basic Structure
A simple robots.txt file might look like:
User-agent: GPTBot
Disallow: /
User-agent: ClaudeBot
Allow: /blog/
Disallow: /
User-agent: *
Allow: /This example blocks GPTBot entirely, allows ClaudeBot to access only the blog section, and allows all other crawlers full access.
Common AI Crawler User-Agents
Here are the most common AI crawler identifiers to use in robots.txt:
- GPTBot - OpenAI (ChatGPT training)
- ChatGPT-User - OpenAI (ChatGPT browsing feature)
- ClaudeBot - Anthropic (Claude training)
- Google-Extended - Google (AI training, separate from search)
- CCBot - Common Crawl (dataset used by many AI companies)
- anthropic-ai - Anthropic (alternative identifier)
- PerplexityBot - Perplexity AI
- YouBot - You.com
The Strategic Decision: Block or Allow?
Deciding whether to allow or block AI crawlers is complex, with valid arguments on both sides:
Reasons to Allow AI Crawler Access
- Visibility and citations: Your content can be discovered and cited by AI answer engines, building brand authority
- Future-proofing: As AI-mediated search grows, blocking crawlers may reduce your visibility in this emerging channel
- Attribution benefits: Many AI systems cite sources, providing brand exposure even without click-through
- Competitive positioning: If competitors allow access and you don't, they may gain citation advantages
Reasons to Block AI Crawler Access
- Zero-click concern: Users may get complete answers without visiting your site, reducing traffic
- Content ownership: You may prefer to control how your content is used in AI training or responses
- Monetization: If your business model depends on ad revenue or conversions, AI-generated answers may bypass your site entirely
- Selective access: You may want to block training crawlers but allow retrieval crawlers
Strategic Approaches to AI Crawler Management
1. The Open Access Approach
Allow all AI crawlers full access to your content. This maximizes visibility in AI-powered systems and positions you for citation and brand recognition.
User-agent: *
Allow: /Best for: Publishers, educational resources, thought leaders, and brands prioritizing awareness over direct traffic.
2. The Selective Access Approach
Allow retrieval crawlers (for real-time citation) but block training crawlers (for dataset building):
# Block training crawlers
User-agent: GPTBot
Disallow: /
User-agent: Google-Extended
Disallow: /
User-agent: CCBot
Disallow: /
# Allow retrieval and search crawlers
User-agent: *
Allow: /Best for: Content creators who want real-time citations but object to their content being used in model training datasets.
3. The Partial Access Approach
Allow access to some content (like blog posts and educational material) but block access to other sections (like proprietary tools or premium content):
User-agent: GPTBot
Allow: /blog/
Allow: /guides/
Disallow: /premium/
Disallow: /tools/
Disallow: /Best for: Businesses with mixed business models who want to balance visibility with content monetization.
4. The Complete Block Approach
Block all AI crawlers while allowing traditional search engines:
User-agent: GPTBot
Disallow: /
User-agent: ClaudeBot
Disallow: /
User-agent: Google-Extended
Disallow: /
User-agent: Googlebot
Allow: /
User-agent: Bingbot
Allow: /Best for: Subscription-based businesses, proprietary content creators, and publishers heavily dependent on ad revenue.
Important Considerations
Robots.txt Is a Request, Not a Law
Robots.txt is a voluntary protocol. Well-behaved crawlers respect it, but there's no legal enforcement mechanism. Some crawlers may ignore robots.txt directives.
Dynamic Nature of AI Crawlers
New AI crawlers emerge regularly. You'll need to monitor and update your robots.txt file as new user-agents appear.
Blocking Doesn't Mean Invisibility
Even if you block crawlers, your content may still end up in AI systems through:
- User-submitted content (people pasting your content into ChatGPT)
- Third-party datasets that previously crawled your site
- Content republished or cited on other sites
Search vs. AI Crawlers
Google-Extended is separate from Googlebot (search crawler). Blocking Google-Extended doesn't affect your search rankings, but it may affect your visibility in Google's AI features like AI Overviews.
Monitoring and Adjustment
Your robots.txt strategy shouldn't be set-and-forget:
- Monitor server logs to see which AI crawlers are accessing your site
- Track referral traffic from AI answer engines to understand citation impact
- Stay informed about new AI crawlers and update your robots.txt accordingly
- Periodically reassess your strategy as the AI landscape evolves
The Bottom Line
There's no one-size-fits-all answer to AI crawler access. Your decision should align with your business model, content strategy, and long-term goals.
If you value brand awareness and authority, allowing access makes sense. If your revenue depends heavily on direct traffic and conversions, blocking may be warranted. Most organizations will benefit from a selective approach that balances visibility with control.
Whatever you choose, make it intentional. Understanding and actively managing AI crawler access is now a core part of content strategy in the AI era.