A few years ago, most site owners only had to think about one crawler, Googlebot. Now your server logs may show a long list of unfamiliar bots from OpenAI, Anthropic, Perplexity, and others. Each one has a different purpose, and the choices you make about them affect whether AI tools can find and cite your content.
This guide explains the main types of AI crawlers, what the well-known ones are called, and how to decide which to allow.
- AI crawlers do three different jobs: training, search, and fetching pages on request.
- Blocking one bot doesn’t block the others. Each company has several.
- Allowing search bots can help you get cited in AI answers. Blocking training bots is a separate business decision.
- robots.txt is a request, not a lock. Bad bots ignore it.
Why AI Crawlers Matter for SEO
- Visibility. If a search bot can’t reach your pages, AI tools may not cite you in their answers.
- Control. You decide whether your content can be used to train models.
- Server load. Heavy bot traffic can slow a site, especially a small one, and eat into your crawl budget.
- Measurement. Knowing who visits helps you understand where your content is being used.
The Three Jobs AI Crawlers Do
- Training crawlers collect content to teach AI models. Blocking them keeps your pages out of future training data.
- Search crawlers build the index that an AI search tool uses to find and cite pages. Blocking them can remove you from that tool’s answers.
- User-triggered fetchers load a page in real time because someone asked an assistant about it. They represent an actual reader, and many follow looser rules about robots.txt.
Common AI Crawlers
Names and details change, so always check each company’s current documentation. As a guide, these are the ones you’re most likely to see.
- OpenAI: GPTBot for training, OAI-SearchBot for the ChatGPT search index, and ChatGPT-User for pages fetched on request.
- Anthropic: ClaudeBot for training, Claude-SearchBot for search, and Claude-User for requests made by users.
- Perplexity: PerplexityBot for its search results, and Perplexity-User for page fetches triggered by users.
- Google: Googlebot does the crawling. Google-Extended is a robots.txt token, not a separate crawler, and it controls whether your content is used for Gemini training.
- Apple: Applebot, with Applebot-Extended as the control for AI training use.
- Others: CCBot from Common Crawl, Bytespider from ByteDance, and Meta’s meta-externalagent.
Should You Block or Allow AI Crawlers?
There’s no single right answer, but this framework helps.
- Search and citation bots. For most businesses, allowing these is a sensible default. They’re how AI tools discover your pages and link back to you.
- User-triggered fetchers. These are real people reading your page through an assistant, so blocking them mostly just hurts your readers.
- Training bots. This is the real judgment call. Publishers who worry about their content being used without payment often block them. Others accept training as the price of broader visibility.
One point confuses a lot of people: blocking Google-Extended doesn’t remove you from Google Search or from AI Overviews. Those depend on Googlebot and on the normal snippet controls, such as nosnippet and noindex. Blocking Googlebot would also remove you from regular search, which is almost never what you want.
What AI Crawlers Mean for Your Content
Crawlers read text, so pages that state facts clearly, use headings and lists, and keep key information in plain HTML are easiest for them to use. Some AI crawlers don’t run JavaScript as fully as Googlebot does, so content that only appears after scripts load may be missed. If your site relies on client-side rendering, consider server-side rendering, or at least make sure the most important text is present in the page’s HTML.
How to Control AI Crawlers With robots.txt
Your robots.txt file accepts a rule for each bot. Here’s a simple example that blocks two training bots and welcomes a search bot:
User-agent: GPTBot
Disallow: /
User-agent: ClaudeBot
Disallow: /
User-agent: OAI-SearchBot
Allow: /Remember that each user agent needs its own rule. Blocking GPTBot doesn’t affect OAI-SearchBot or ChatGPT-User, and a subdomain needs its own robots.txt file.
How to See Which AI Crawlers Visit You
- Server logs. Filter your logs by user agent to see which bots visit and how often. See log file analysis.
- CDN or firewall dashboards. Services such as Cloudflare show bot traffic in their analytics.
- Verification. Anyone can fake a user agent. Where it matters, check the visiting IP address against the ranges the company publishes.
How to Manage AI Crawlers: Five Steps
- Decide your goal. Do you want to be cited in AI answers, keep your content out of training, or both?
- List the bots you care about. Use each company’s official documentation, not an old list.
- Write your robots.txt rules. Allow what helps you and disallow what doesn’t.
- Check your logs. Confirm that bots respond to the changes, and watch for new ones.
- Review every few months. New crawlers and renamed ones appear often.
Common AI Crawler Mistakes
- Blocking one bot and assuming you’ve blocked a whole company. Each company runs several.
- Copying an old block list. Names change, and you can end up blocking the wrong things.
- Blocking search bots by accident. That can quietly remove you from AI answers.
- Treating robots.txt as security. It doesn’t protect private content, and bad actors ignore it.
- Forgetting server load. If bots slow your site, use rate limits as well as robots.txt.
Example: A Sensible Setup for a Business Site
Picture a services company that wants to show up in AI answers but doesn’t want its articles used to train models. A sensible setup would allow Googlebot and the search bots, allow user-triggered fetchers, and disallow the main training bots in robots.txt. It would also check server logs monthly for new bots and set a rate limit at the firewall for anything that crawls too hard. That takes under an hour to set up, and a quick review every few months keeps it current.
AI Crawlers and llms.txt
You may have heard about a file called llms.txt. It’s a proposed text file that gives AI tools a tidy summary of your site’s most useful pages. It doesn’t control access the way robots.txt does, and support from AI companies varies, so treat it as a low-cost extra and not a replacement for good content and clean crawling rules.
AI Crawler FAQs
Do AI crawlers follow robots.txt?
Reputable ones generally do, although user-triggered fetchers sometimes work differently because a person asked for the page. Unidentified scrapers often ignore it, so use firewall rules or rate limits for those.
Will blocking AI crawlers hurt my Google rankings?
Blocking training bots such as GPTBot or Google-Extended doesn’t affect your Google rankings. Blocking Googlebot would, so don’t do that.
Should I allow AI search crawlers?
For most sites, yes. Search crawlers are how AI tools find and cite your pages. If you want visibility in AI answers, you need them to be able to reach your content.
Is llms.txt the same as robots.txt?
No. robots.txt controls access. An llms.txt file is a proposed way to point AI tools to your most useful content. They do different jobs, and support for llms.txt varies.
Not Sure Which Bots to Allow?
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