AI crawlers are automated bots run by AI companies that fetch web pages so their systems can learn from them, index them for AI search, or read them live when a user asks a question. GPTBot, OAI-SearchBot, ClaudeBot and PerplexityBot are common examples.
For a business, these bots decide whether your content can show up, and get cited, in tools like ChatGPT, Claude and Perplexity. Knowing which bot does what lets you make deliberate choices instead of blocking or allowing everything by accident.
What are AI crawlers?
A crawler is a program that visits URLs, downloads the content and follows links to find more pages. Search engines have used them for decades (see crawling). AI crawlers do the same job for AI products, and each one identifies itself with a user agent name in its requests.
As of October 2026, most major AI companies split their bots by purpose. That split matters because blocking one bot does not block the others.
- Training crawlers collect public content that may be used to train future models. OpenAI's GPTBot and Anthropic's ClaudeBot fall here.
- Search or indexing crawlers build the index an AI search product pulls answers from. Examples include OAI-SearchBot, Claude-SearchBot and PerplexityBot.
- User-triggered fetchers visit a page only when a person asks the assistant something that needs it. ChatGPT-User, Claude-User and Perplexity-User work this way.
Google handles this differently. Gemini and Google's AI features draw on content Googlebot already crawls for Search. Google offers a separate robots.txt token, Google-Extended, that controls whether that content is used to train Gemini models and to ground Gemini answers. Google says Google-Extended does not affect inclusion or ranking in Google Search.
Why AI crawlers matter for visibility
If an AI search bot can't reach a page, that page is unlikely to be retrieved and cited in that product's answers. OpenAI states plainly that sites which opt out of OAI-SearchBot won't appear in ChatGPT search answers, though they may still show up as navigational links.
Training crawlers affect something slower: what a model "knows" about your brand from its training data. Search and user-triggered bots affect what an assistant can look up right now and link to, which is where an AI citation comes from.
There is also a cost side. AI bots add server load, and some publishers object to their content training models without payment. In July 2025, Cloudflare announced it was changing its default to block AI crawlers unless they pay for content, which means some sites may block AI bots without realizing it.
How AI crawlers work
Discovery and fetching
AI crawlers find URLs through links, sitemaps and, for user-triggered fetchers, the page a user or a search step points them to. They request the page and read the HTML the server returns.
Reading robots.txt
Reputable crawlers check your robots.txt file before crawling. OpenAI, Anthropic and Perplexity all document user agent names you can allow or disallow. Anthropic also says it honors the non-standard Crawl-delay directive for ClaudeBot. Keep in mind that, as Google's robots.txt guide notes, compliance is voluntary and not every bot obeys.
User-triggered fetchers are the main exception. OpenAI says robots.txt rules may not apply to ChatGPT-User, and Perplexity says Perplexity-User generally ignores robots.txt because a person requested the fetch.
Rendering, or not
Googlebot renders JavaScript. Many AI crawlers do not. In a December 2024 analysis of its network, Vercel found that none of the major AI crawlers it studied, including GPTBot, ClaudeBot and PerplexityBot, executed JavaScript. Gemini, which uses Google's infrastructure, was an exception. Behavior may have changed since, but content that only appears after client-side rendering remains a real risk (see JavaScript SEO).
An example of AI crawler rules in practice
Imagine a regional accounting firm that wants to be recommended in AI search but doesn't want its in-depth guides used to train models. A reasonable robots.txt setup would allow OAI-SearchBot, Claude-SearchBot and PerplexityBot, while disallowing GPTBot and ClaudeBot and adding a Google-Extended disallow if it also wants to opt out of Gemini training and grounding.
The trade-off is worth spelling out. Blocking training bots may mean future models know less about the firm, and blocking Google-Extended also affects Gemini grounding. There is no single right answer. The point is to choose on purpose, per bot.
How to manage AI crawlers
- Audit what you block today. Read your live robots.txt and check CDN or firewall settings, such as bot management rules, that may block AI user agents before robots.txt even matters.
- Decide per purpose. Treat training, search and user-triggered bots as separate decisions. Most businesses that want AI visibility allow the search and user bots at a minimum.
- Use the documented user agent names. Copy names from each company's official docs, since they change over time. OpenAI notes robots.txt changes for search can take about 24 hours to apply.
- Serve key content in the initial HTML. Use server-side rendering or static generation for pages you want AI tools to read, including prices, product details and FAQs.
- Check your server logs. Look for AI user agents to confirm they are reaching important pages and not hitting errors or redirect loops.
- Don't rely on robots.txt for privacy. Anything sensitive should sit behind a login, not just a disallow rule.
Common mistakes with AI crawlers
- Blocking everything "AI" at once. Many copy-paste blocklists remove you from AI search along with training.
- Assuming Google-Extended controls AI Overviews. Google's documentation ties Google-Extended to Gemini training and grounding, not to Search features. AI Overviews draw on the regular Search index.
- Forgetting the CDN. A firewall or default bot setting can override a welcoming robots.txt.
- Hiding content behind JavaScript. If the answer only loads in the browser, many AI bots never see it.
How Butter approaches AI crawlers
At Butter, AI crawler access is one of the first things we check, because no amount of great content helps if the bots that power AI search can't read it. In our GEO plan, monthly AI prompt testing and indexing strategy include reviewing which AI user agents your robots.txt and hosting setup allow, and flagging pages that rely on client-side rendering. On the GEO+SEO plan, our technical SEO fixes cover crawl issues like broken links and blocked resources. We don't make the training opt-out decision for you. We explain the trade-offs and let you choose. You can see how this fits our broader GEO service.
Frequently asked questions
Should I block AI crawlers?
It depends on your goals. If you want to appear in AI search answers, allow the search and user-triggered bots. Blocking training crawlers like GPTBot or ClaudeBot is a separate choice that mainly affects future model training.
Does blocking GPTBot remove me from ChatGPT search?
No. OpenAI uses OAI-SearchBot for ChatGPT search and GPTBot for training. To opt out of ChatGPT search results, you would need to disallow OAI-SearchBot.
Do AI crawlers follow robots.txt?
The major AI companies say their automated crawlers respect robots.txt. User-triggered fetchers, like ChatGPT-User and Perplexity-User, may not, because a person asked for the page. Some lesser-known bots ignore robots.txt entirely.
Can AI crawlers read JavaScript content?
Many cannot. Vercel's 2024 analysis found major AI crawlers fetched JavaScript files without executing them. Putting important content in the server-rendered HTML is the safest approach.