What is AI Crawlers?
AI crawlers are automated agents operated by AI companies that fetch web content either to build training corpora or to retrieve sources at the moment a user asks a question. The two purposes use different user agents and are controlled separately in robots.txt.
Also known as: AI bots, GPTBot, ClaudeBot, PerplexityBot
The distinction between the two families is the part most sites get wrong, and it has real consequences. Training crawlers — GPTBot, ClaudeBot, Google-Extended, Applebot-Extended — determine whether a brand exists in a model's background knowledge. Retrieval crawlers — OAI-SearchBot, ChatGPT-User, Claude-User, PerplexityBot — determine whether a page can be cited in a specific answer today.
A site that blocks the training family but allows retrieval can still be cited live. A site that blocks the retrieval family cannot be cited in answers at all, regardless of how well known the brand is otherwise. Blanket-blocking "AI bots" without separating the two usually removes citation eligibility as an unintended side effect.
Crawler visits are observable in server logs, which makes them one of the few directly measurable signals in this area — a leading indicator that arrives before citations do.
Why AI Crawlers matters
Robots.txt decides eligibility. Content quality is irrelevant to an engine that was never permitted to fetch the page.
Training agents
GPTBot, ClaudeBot, Google-Extended, Applebot-Extended, CCBot, Amazonbot — these shape whether the model knows the brand at all.
Retrieval agents
OAI-SearchBot, ChatGPT-User, Claude-User, Claude-SearchBot, PerplexityBot, Perplexity-User — these decide live citation eligibility.
Log analysis is the ground truth
Crawler hits in server logs confirm access is working, and typically move before citation rates do.
Blocking is a business decision
Publishers with licensing leverage may reasonably block training crawlers. Blocking retrieval crawlers forfeits citation with no comparable upside.
Common questions
It depends which family and what your business is. If you sell access to content, blocking training crawlers is a defensible negotiating position. Blocking retrieval crawlers is a different decision: it removes you from AI answers entirely, which for most businesses forfeits visibility without protecting anything.
Direct AEO AnswerBlocking training crawlers can be reasonable for publishers protecting licensable content. Blocking retrieval crawlers removes eligibility for citation in AI answers and is rarely advantageous.