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Citlyze Team

GPTBot, ClaudeBot, PerplexityBot: A Marketer's Guide to AI Crawlers

Which AI crawlers visit your site, what each one does, when to allow or block them, and how to see their activity without reading server logs.

CrawlersGEO

AI companies run multiple crawlers with different jobs, and the difference decides your visibility. Some bots collect training data, some build search indexes, and some fetch pages live while a user waits for an answer. Blocking the wrong one quietly removes you from AI answers; allowing them all without measurement leaves you blind to a growing share of your real traffic.

This guide covers the major crawlers, the allow-or-block decision, and how a marketing team can see the activity without becoming log-file archaeologists.

The crawlers that matter

OpenAI operates three, documented in its crawler overview:

  • GPTBot collects training data for future models.
  • OAI-SearchBot builds the index behind ChatGPT's search.
  • ChatGPT-User fetches pages live during conversations, on a user's behalf.

Anthropic mirrors the pattern with three agents, per its support documentation: ClaudeBot for training, Claude-SearchBot for search indexing, and Claude-User for live fetches. Trade coverage at Search Engine Journal walks through what the split means for robots decisions.

Perplexity documents two in its crawler docs: PerplexityBot for indexing and Perplexity-User for live retrieval.

Google complicates the picture usefully: regular Googlebot feeds search and the AI surfaces built on it, while Google-Extended is a separate control for Gemini training, per Google's crawler documentation. Blocking Googlebot removes you from search itself; blocking Google-Extended only opts out of model training.

Others worth knowing: Bytespider (ByteDance), Meta-ExternalAgent, Amazonbot, and CCBot (Common Crawl, whose corpus feeds many models).

Allow or block: an actual framework

The decision is per-crawler-type, and it is written in robots.txt under the rules of RFC 9309:

  • Search and live-fetch bots (OAI-SearchBot, ChatGPT-User, Claude-SearchBot, Claude-User, PerplexityBot, Perplexity-User): allow these if you want AI visibility. They are the retrieval layer; blocking them removes you from answers and citations. For most brands this is the entire growth surface.
  • Training bots (GPTBot, ClaudeBot, Google-Extended, CCBot): a genuine policy choice. Allowing them builds your presence into future models, the slow layer of visibility. Blocking them protects content from training use at the cost of that future presence. Media companies often block; most B2B brands benefit from allowing.

A visibility-first robots.txt keeps it simple:

# Allow AI search and live retrieval
User-agent: OAI-SearchBot
Allow: /

User-agent: ChatGPT-User
Allow: /

User-agent: PerplexityBot
Allow: /

# Training crawlers: your policy call
User-agent: GPTBot
Allow: /

Two caveats keep expectations honest. Robots.txt is voluntary compliance, and enforcement gaps are real: Cloudflare documented undeclared crawling behavior that bypassed no-crawl directives. And your CDN or firewall may be blocking AI crawlers right now without anyone deciding to, one of the most common findings in a GEO audit.

What AI crawlers can and cannot read

Most AI fetchers read your HTML as delivered and do not execute JavaScript the way Googlebot's rendering pipeline does. Sites that render their substance client-side can serve these bots an empty shell. The checklist:

  • Core content present in the initial HTML response.
  • Key pages fast, public, and not gated behind interstitials the bots cannot pass.
  • Clean structure: headings, lists, and schema.org markup that make extraction unambiguous.

Watching crawler activity without server logs

Crawler visits are real behavioral data: which pages AI systems fetch, how often, and which company's bots are active on your site. Historically that meant log-file analysis, which is why the data mostly went unwatched by marketing teams. The lightweight alternative is edge-level capture: a small snippet at your CDN or middleware identifies AI user agents, verifies them, and records the visit. That yields a live readout of GPTBot, ClaudeBot, and PerplexityBot activity, per page and per day, plus the human visits that arrive from AI answers via referrers, without touching raw logs. This is precisely what AI crawler tracking provides, with install snippets for Cloudflare, Vercel, and WordPress documented in the setup guide.

One discipline note: a crawl is an input, never the outcome. Fetch activity tells you the pipeline's first stage is working; it does not guarantee citations, a distinction we treat fully in a crawler visit is not a citation.

FAQ

Should I block GPTBot? Only if opting out of model training is worth reduced presence in future models. Blocking GPTBot does not remove you from ChatGPT search; that is OAI-SearchBot and ChatGPT-User.

Do AI crawlers respect robots.txt? The major documented crawlers state they do, with documented exceptions in the wild. Treat robots.txt as your policy statement and verify behavior by watching actual visits.

How do I know if AI crawlers visit my site? Server logs, or edge-level tracking that identifies and verifies bot user agents. If you have never looked, expect more activity than you assumed.

See the bots on your site this week

Citlyze's crawler analytics show which AI bots visit, what they fetch, and how it trends, alongside the human visits AI answers send you. Install takes minutes with the tracking snippet, included on every plan at citlyze.com/pricing.