AI Crawlers: The Complete Guide to GPTBot, ClaudeBot, and the Rest

AI crawlers are the bots that gather the content AI engines train on and cite from, and right now most site owners have no idea which ones they are allowing or blocking. During the scraping debates of recent years, a wave of sites added aggressive AI-bot blocks to robots.txt and forgot about it. Many of those same teams now wonder why ChatGPT, Claude, and Perplexity never mention them. The answer is often sitting in a file they have not opened in two years.

This guide names every major AI crawler, explains what each one does, separates the crawlers that gather training data from the ones that fetch live citations, and walks through how to control them in robots.txt. The allow-versus-block decision is genuinely strategic, so by the end you will be able to make a deliberate choice rather than an accidental one.

AI Crawlers You Need to Know by Name

Different operators run different bots, and several operators run more than one for different purposes. Knowing the names is the prerequisite to controlling them.

GPTBot (OpenAI). Gathers content used to improve OpenAI's models. This is primarily a training crawler.

OAI-SearchBot (OpenAI). Powers ChatGPT search results and live citations. Blocking this can keep you out of ChatGPT's live answers even if GPTBot is allowed, so treat the two separately.

ClaudeBot (Anthropic). Anthropic's main crawler, gathering content Claude can draw on. If you want Claude citations, this one needs access.

Claude-SearchBot (Anthropic). Associated with Claude's live search and citation behaviour, distinct from the broader training crawl.

Google-Extended (Google). Not a separate bot but a robots.txt token that controls whether your content is used for Gemini and other Google AI training, independent of normal Googlebot indexing.

PerplexityBot (Perplexity). Crawls for Perplexity's retrieval-first answer engine. Given how citation-heavy Perplexity is, access here maps closely to visibility.

Bytespider (ByteDance). ByteDance's aggressive crawler, associated with TikTok's parent company. Known for heavy crawl volume, which leads some sites to rate-limit or block it.

Meta crawlers (Meta-ExternalAgent and related). Meta operates crawlers gathering content for its AI products. Expect more of these as Meta AI expands across its apps.

Training Crawlers Versus Search Crawlers

The most important distinction in this whole topic is purpose, because it changes what blocking actually costs you.

Training crawlers feed the model's frozen knowledge. GPTBot, ClaudeBot in its broad role, and Google-Extended gather text that may shape what a model knows in general. Blocking these is a stance about training use; it does not directly remove you from live, cited answers.

Search crawlers feed live citations. OAI-SearchBot, Claude-SearchBot, and PerplexityBot fetch content for answers generated right now, with sources shown. Blocking these directly removes you from the citations users see, which is usually the opposite of what an SEO team wants.

Why the difference matters: a team can reasonably decide to opt out of training while staying eligible for live citations, but only if it understands which token does which. A blanket "block all AI bots" rule throws away live visibility along with training, and that is the accidental own-goal so many sites have committed. Getting this right is foundational to how to optimise for AI search.

Controlling AI Crawlers in robots.txt

robots.txt is the primary lever, and it works the same way for AI crawlers as for any other: user-agent blocks followed by allow or disallow rules.

Audit what you currently allow. Open your robots.txt today and list every user-agent rule. Look specifically for blanket User-agent: * disallows and any explicit AI-bot blocks added in the past. You cannot make a good decision until you know your starting point.

Be precise per bot. Because operators run separate training and search crawlers, you can allow OAI-SearchBot while having a different stance on GPTBot, or allow ClaudeBot while using Google-Extended to opt out of Gemini training. Write rules per user-agent rather than swinging a blanket block.

Remember robots.txt is advisory. Reputable crawlers honour it, but it is not an access control. For bots you genuinely need to stop, such as an abusive crawler hammering your origin, server-level rate limiting or blocking is more reliable than a polite directive.

Re-check after migrations. Site moves, CDN changes, and new security tooling can silently reintroduce blanket blocks. Add an AI-crawler check to your launch checklist.

Allow or Block: Making the Strategic Call

There is no universally correct answer, but there is a framework.

Allow if you want AI visibility. If your goal is to be cited by ChatGPT, Claude, Perplexity, and Gemini, the default should be to allow the search crawlers at minimum. You cannot be cited from content the engine was never allowed to fetch.

Consider training separately. Some publishers with valuable proprietary content opt out of training while staying open to live citation, balancing protection against discoverability. That is a legitimate, deliberate position, not a contradiction.

Watch for cost and abuse. Crawlers like Bytespider can generate heavy load. Rate-limiting an aggressive bot is reasonable even when you allow the engines you care about. Distinguish "this bot is expensive" from "this bot brings me visibility."

Measure the result. After you adjust access, track whether your citation rate actually moves. This is where AI citation tracking closes the loop on a robots.txt change.

Frequently Asked Questions

Q: Will blocking GPTBot remove me from ChatGPT entirely? Not entirely. GPTBot is primarily a training crawler, while OAI-SearchBot fetches content for live ChatGPT search citations. Blocking GPTBot is a stance on training; to stay in live answers you need to keep OAI-SearchBot allowed.

Q: Does allowing AI crawlers hurt my normal Google ranking? No. Google-Extended is a separate token from Googlebot, so opting in or out of Gemini training has no effect on standard Google indexing or ranking. They are controlled independently in robots.txt.

Q: How do I block an aggressive crawler like Bytespider? You can disallow it in robots.txt, but because robots.txt is advisory, server-level or CDN-level rate limiting and blocking are more reliable for a bot generating heavy load. Reserve hard blocks for genuine abuse rather than blanket AI-bot fear.

Q: Should a small business allow all the AI crawlers? In most cases yes, because the upside is being discoverable in AI answers and the downside is minimal for typical marketing content. The main exception is proprietary or paywalled content where you may want to allow live search but opt out of training. See does ChatGPT use Google for which crawler backs which engine.

The Bottom Line

AI crawlers fall into two camps: training crawlers like GPTBot, ClaudeBot's broad role, and Google-Extended that shape what models know, and search crawlers like OAI-SearchBot, Claude-SearchBot, and PerplexityBot that fetch the content shown in live citations. Blocking the wrong ones quietly erases your AI visibility, which is exactly what so many sites did by accident. Audit your robots.txt today, write per-bot rules that match your strategy, and then verify the result. bing.ly makes that verification simple for small teams by tracking your mention rate across the major engines so you can see whether opening up to a crawler actually earned you citations.