Before an AI system can ever cite your content, a crawler has to find and index it. Blocking the wrong bot in robots.txt means no AI citations, no matter how well-optimized your content is. Here's how to get it right.
R
Rowan
Founder, GEOBoost ·
5 min read
Why AI crawlers are different from Googlebot
Every major AI platform operates its own web crawler, separate from Google's. When you update robots.txt, you're not choosing between "search engines" and "everyone else" — you're making individual decisions about each crawler by name.
Googlebot indexes your site for traditional search rankings. GPTBot indexes it for ChatGPT. ClaudeBot for Claude. PerplexityBot for Perplexity. Block any of them specifically and that platform cannot cite your content, even if all the others can access it freely.
Many sites accidentally block AI crawlers through overly broad rules — for example, blocking all unknown user agents — without realizing the impact on AI search visibility.
The major AI crawlers
GPTBot
OpenAI (ChatGPT)
Used by OpenAI to index web content for ChatGPT's knowledge base and real-time web search. Blocking GPTBot prevents your content from appearing in ChatGPT answers. Officially documented by OpenAI at platform.openai.com.
ClaudeBot
Anthropic (Claude)
Anthropic's crawler for indexing content used in Claude's web-aware responses. Respects robots.txt by default. Documented at support.anthropic.com.
PerplexityBot
Perplexity AI
Powers Perplexity's real-time web answers and citation system. Perplexity AI actively cites sources in its answers, making PerplexityBot access particularly valuable for content discoverability.
Google-Extended
Google (AI Overviews)
A separate robots.txt token from Googlebot, used specifically for Google's AI products including AI Overviews and Gemini. Blocking Google-Extended does not affect regular Google search rankings — only AI-generated answer inclusion.
meta-externalagent
Meta AI
Meta's crawler for indexing content used in Meta AI (integrated into WhatsApp, Instagram, and Facebook). A newer addition to watch as Meta AI grows in usage.
How to check your robots.txt
Your robots.txt file lives at the root of your domain: yourdomain.com/robots.txt. Open it in a browser and look for any rules that might affect AI crawlers. The two patterns to watch for:
# This blocks ALL bots — including all AI crawlers
User-agent: *
Disallow: /
# This specifically blocks OpenAI's crawler
User-agent: GPTBot
Disallow: /
A broad User-agent: * rule with Disallow: / blocks every bot that doesn't have its own explicit allow rule — including every AI crawler.
The correct robots.txt setup for GEO
To allow all AI crawlers while keeping Googlebot rules intact, your robots.txt should explicitly allow each crawler. Here's a clean starting point:
Quick win: After fixing robots.txt, check whether your site also has an llms.txt file. This emerging standard lets you provide AI systems with a structured summary of your site's content and permissions — GEOBoost checks for it automatically on every scan.
GEOBoost checks your robots.txt automatically on every scan and flags any blocked AI crawlers under the AI Crawler Access category.
02
Check the AI Crawler Access score
A score below 100 in this category means at least one major AI crawler is being blocked. GEOBoost lists exactly which ones.
03
Update robots.txt and re-scan
After making changes, run a new scan to confirm all crawlers are allowed. AI indexing typically takes a few days after the block is lifted.
Frequently asked questions
Common questions about AI crawlers and robots.txt.
Should I block AI crawlers to protect my content?
Blocking AI crawlers means your content cannot be cited in AI-generated answers. If your goal is to drive brand awareness or be recognized as a source in AI search, you want crawlers to access your content. If you have proprietary data you want to keep private, selective blocking by folder is an option — but blocking all AI crawlers will make you invisible in AI search.
Does blocking GPTBot affect my Google ranking?
No. GPTBot is OpenAI's crawler and is completely separate from Googlebot. Blocking GPTBot does not affect your Google search rankings. However, blocking Google-Extended (a separate token used for AI Overviews) does reduce your chance of appearing in Google's AI-generated answers.
What is the difference between GPTBot and Google-Extended?
GPTBot is OpenAI's crawler, used to train ChatGPT and power real-time web search in ChatGPT. Google-Extended is a separate robots.txt token that controls whether Google can use your content for AI Overviews and Gemini. You can block one without affecting the other.