AI Crawlers Explained: GPTBot, ClaudeBot, and More

Alongside Googlebot and Bingbot, a growing list of crawlers operated by AI companies now regularly visit most websites, each with its own name, purpose, and robots.txt rules. Understanding what they actually do — and that they don't all do the same thing — matters if you're trying to make a deliberate decision about AI visibility rather than leaving it to default settings you've never looked at. This guide covers the major ones, the real distinction between what they're used for, and how to manage access sensibly.

Two different jobs AI crawlers do

The most important distinction to understand isn't which company runs which bot — it's what the crawl is for. Broadly, AI crawlers do one or both of two different jobs:

• Training data collection — gathering large volumes of web content used to train or improve an underlying language model. This happens periodically, in bulk, and isn't tied to any specific user's question in real time.
• Live retrieval and citation — fetching a page in real time (or from a recent index) specifically to answer a specific user's question, often with a direct citation or link back to the source. This is the crawl activity most directly tied to being mentioned in an AI-generated answer.

Some companies run entirely separate crawlers for each purpose, with separate user-agent names, so you can choose to allow one without the other — for instance, opting out of having your content used for model training while still allowing your site to be cited in live, retrieval-based answers. This distinction is exactly why it's worth knowing the specific crawlers by name rather than treating "AI bots" as one undifferentiated category.

The major crawlers and what they're generally for

User-agent names and their exact purposes are set by each company and do change over time as products evolve — treat the following as a reliable general map, and verify current specifics against each company's published crawler documentation if you need precision.

• GPTBot (OpenAI) — crawls web content used to train and improve OpenAI's models. A separate crawler, OAI-SearchBot, handles retrieval for ChatGPT's search and browsing features, and ChatGPT-User fetches a specific page in real time when a user asks ChatGPT to look at a URL directly.
• ClaudeBot (Anthropic) — Anthropic's general-purpose crawler, used to gather content that supports Claude's models and features, including web search and browsing capabilities.
• PerplexityBot (Perplexity) — crawls and indexes content used to generate Perplexity's answers, with a companion agent that fetches specific pages in real time when a user's query points to them.
• Google-Extended (Google) — a separate, opt-out-able token controlling whether your content can be used for Google's generative AI features (like Gemini and AI Overviews' underlying model training). This is distinct from Googlebot, which handles ordinary Search indexing — disallowing Google-Extended does not remove you from regular Google Search.
• Applebot-Extended (Apple) — similarly, a distinct token controlling use of your content in Apple's generative AI features, separate from the standard Applebot that supports Siri and Spotlight search.
• CCBot (Common Crawl) — not run by an AI company directly, but by the nonprofit Common Crawl project, whose large public web archive has been used as training data by numerous AI labs. Worth knowing about even though it's not a household name.
• Bytespider (ByteDance) and Amazonbot (Amazon) — crawlers run by companies with their own AI initiatives, generally used for training data collection.

How to check which crawlers are actually reaching your site

Your robots.txt file states your intended rules, but it doesn't tell you whether crawlers are actually visiting or whether your site is even structured in a way they can process (a page that requires JavaScript to render its content can be technically "allowed" and still fail to deliver anything readable to a crawler that doesn't execute JavaScript). Checking your raw server logs or a log-analysis feature from your host for these user-agent strings is the most direct way to confirm actual activity — see how to check if AI bots can actually crawl your site for a step-by-step approach.

Should you block them?

There's no universally correct answer — it depends on your actual goal, and it's worth deciding deliberately rather than by default.

• If your goal is being found and cited by AI assistants when prospective customers ask relevant questions — true for most local service businesses — allowing the major retrieval-oriented crawlers (OAI-SearchBot, ChatGPT-User, PerplexityBot, ClaudeBot, Google-Extended) supports that goal directly.
• If your business model depends on gated or subscription content that you don't want reused elsewhere for free, blocking training-oriented crawlers (GPTBot, CCBot, Bytespider) is a reasonable, defensible choice — this is a much more common consideration for publishers and content businesses than for local service sites.
• Blocking everything indiscriminately, often the accidental result of a restrictive robots.txt template applied without review, removes you from consideration for AI-driven visibility entirely — worth auditing rather than assuming your current setup is intentional.

Setting the rules in robots.txt

Crawler access is controlled the same way traditional search crawler access is — with Allow and Disallow rules in your site's robots.txt file, scoped to a specific crawler's user-agent name. A block explicitly disallowing one crawler while leaving others untouched looks like:

• User-agent: GPTBot followed by Disallow: / blocks that one crawler entirely, while leaving every other crawler's rules (including Googlebot's) completely unaffected.
• Omitting a crawler from robots.txt entirely means the default behavior applies — generally, no restriction — so an intentional "allow" is often just the absence of a block, not a rule you need to write explicitly.

Building this correctly by hand is easy to get subtly wrong — a misplaced rule can accidentally block Googlebot while trying to block an AI crawler, which would hurt regular search visibility. The robots.txt generator builds a valid file with explicit AI crawler rules without that risk.