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AI Bot Strategy: Block Training, Allow Search Crawlers

•9 min read

Smart AI Bot Strategy: Allow Search Bots, Block Training Crawlers

Updated: February 2025 | The balanced approach to AI crawler management

The knee-jerk reaction to AI crawlers is to block everything. But that's not always the smartest move. In 2025, some AI bots can actually drive traffic to your site while others just steal your content. This guide explains the difference and shows you how to implement a selective blocking strategy.

The Three Types of AI Bots

Not all AI crawlers are created equal. Understanding the difference is crucial:

1. Training Bots (Block These)

Purpose: Collect data to train AI models

Examples:

  • GPTBot (OpenAI)
  • ClaudeBot (Anthropic)
  • Google-Extended (Google)
  • Meta-ExternalAgent (Meta)
  • CCBot (Common Crawl)
  • Bytespider (ByteDance)

Why block: They take your content to improve AI models. You get nothing in return.

2. AI Search Bots (Consider Allowing)

Purpose: Index content to answer user queries with citations

Examples:

  • PerplexityBot (Perplexity)
  • OAI-SearchBot (OpenAI)
  • YouBot (You.com)
  • iaskspider (iAsk.Ai)

Why allow: They can send traffic to your site when users ask related questions.

3. AI Assistant Bots (Usually Allow)

Purpose: Fetch pages in real-time when users ask specific questions

Examples:

  • ChatGPT-User (OpenAI)
  • Claude-Web (Anthropic)
  • DuckAssistBot (DuckDuckGo)
  • MistralAI-User (Mistral)
  • Perplexity-User (Perplexity)

Why allow: They cite your content and can drive referral traffic.

Why a Selective Strategy Matters

The Problem with Blocking Everything

If you block ALL AI bots, you:

  • Miss out on AI search engine traffic
  • Prevent AI assistants from citing your content
  • Lose visibility as AI becomes a major discovery channel

The Problem with Allowing Everything

If you allow ALL AI bots, you:

  • Let companies train on your content for free
  • Lose control over how your content is used
  • May face competition from AI-generated content based on yours

The Smart Middle Ground

Block bots that take value (training), allow bots that give value (search/citations).

Traffic Impact Analysis

How different AI bots affect your traffic:

Bot Type Traffic Impact Content Use Recommendation
Training bots Zero Model training Block
AI search bots Potential positive Search results + citations Allow or Monitor
AI assistants Small positive Real-time answers + citations Allow

Real Data from Publishers

Early data from sites implementing selective blocking:

  • Blocking training bots only: No traffic loss, 40-60% bandwidth savings
  • Blocking everything: Some report 5-15% traffic decline from AI search
  • Allowing everything: No immediate impact, but content appears in competitors' AI responses

Implementation: The Selective robots.txt

Strategy 1: Block Training, Allow Search & Assistants

# === BLOCK: AI Training Bots ===
# These bots collect data to train AI models
# You receive no benefit from allowing them

User-agent: GPTBot
Disallow: /

User-agent: ClaudeBot
Disallow: /

User-agent: anthropic-ai
Disallow: /

User-agent: Google-Extended
Disallow: /

User-agent: CCBot
Disallow: /

User-agent: Meta-ExternalAgent
Disallow: /

User-agent: FacebookBot
Disallow: /

User-agent: Bytespider
Disallow: /

User-agent: Baiduspider
Disallow: /

User-agent: Sogou
Disallow: /

User-agent: 360Spider
Disallow: /

User-agent: ChatGLM-Spider
Disallow: /

User-agent: DeepSeekBot
Disallow: /

User-agent: cohere-ai
Disallow: /

User-agent: PanguBot
Disallow: /

User-agent: xAI-Grok
Disallow: /

# === ALLOW: AI Search Bots ===
# These bots index content for AI search engines
# They can drive traffic to your site

User-agent: PerplexityBot
Allow: /

User-agent: OAI-SearchBot
Allow: /

User-agent: YouBot
Allow: /

User-agent: iaskspider
Allow: /

User-agent: Kangaroo Bot
Allow: /

# === ALLOW: AI Assistants ===
# These fetch content in real-time for user queries
# They cite your content and may drive referral traffic

User-agent: ChatGPT-User
Allow: /

User-agent: Claude-Web
Allow: /

User-agent: DuckAssistBot
Allow: /

User-agent: MistralAI-User
Allow: /

User-agent: Perplexity-User
Allow: /

User-agent: Amazonbot
Allow: /

Strategy 2: Block Everything Except Assistants

More restrictive approach if you're concerned about AI search:

# Block all AI training bots
User-agent: GPTBot
User-agent: ClaudeBot
User-agent: anthropic-ai
User-agent: Google-Extended
User-agent: CCBot
User-agent: Meta-ExternalAgent
User-agent: Bytespider
User-agent: PerplexityBot
User-agent: YouBot
Disallow: /

# Only allow real-time assistant bots
User-agent: ChatGPT-User
Allow: /

User-agent: Claude-Web
Allow: /

User-agent: DuckAssistBot
Allow: /

Strategy 3: Monitor First, Then Decide

Not sure what to allow? Start by monitoring:

  1. Allow all AI bots for 30 days
  2. Analyze your server logs for AI bot traffic
  3. Check referral traffic from AI services
  4. Then implement blocking based on data

Server-Level Selective Blocking

robots.txt doesn't work for aggressive bots. Use server rules too.

Nginx Configuration

# Block AI training bots at server level
map $http_user_agent $block_ai_training {
    default 0;
    ~*(GPTBot|ClaudeBot|anthropic-ai|Google-Extended|CCBot|Meta-ExternalAgent|Bytespider|Baiduspider|Sogou|360Spider|ChatGLM|DeepSeekBot|cohere-ai|PanguBot|xAI-Grok) 1;
}

# Allow AI search and assistant bots (not in the block list)
# PerplexityBot, YouBot, ChatGPT-User, Claude-Web, etc. will pass through

server {
    # ... your config ...

    if ($block_ai_training) {
        return 403;
    }
}

Apache .htaccess

# Block AI training bots only
<IfModule mod_rewrite.c>
RewriteEngine On

# Training bots - BLOCK
RewriteCond %{HTTP_USER_AGENT} GPTBot [NC,OR]
RewriteCond %{HTTP_USER_AGENT} ClaudeBot [NC,OR]
RewriteCond %{HTTP_USER_AGENT} anthropic-ai [NC,OR]
RewriteCond %{HTTP_USER_AGENT} Google-Extended [NC,OR]
RewriteCond %{HTTP_USER_AGENT} CCBot [NC,OR]
RewriteCond %{HTTP_USER_AGENT} Meta-ExternalAgent [NC,OR]
RewriteCond %{HTTP_USER_AGENT} Bytespider [NC,OR]
RewriteCond %{HTTP_USER_AGENT} Baiduspider [NC,OR]
RewriteCond %{HTTP_USER_AGENT} Sogou [NC,OR]
RewriteCond %{HTTP_USER_AGENT} 360Spider [NC,OR]
RewriteCond %{HTTP_USER_AGENT} ChatGLM [NC,OR]
RewriteCond %{HTTP_USER_AGENT} DeepSeekBot [NC,OR]
RewriteCond %{HTTP_USER_AGENT} cohere-ai [NC,OR]
RewriteCond %{HTTP_USER_AGENT} xAI-Grok [NC]
RewriteRule .* - [F,L]

# Search & Assistant bots pass through automatically
# PerplexityBot, YouBot, ChatGPT-User, etc. are NOT in the list above
</IfModule>

Cloudflare Selective Rules

Custom WAF Rule for Training Bots Only

Rule Name: Block AI Training Crawlers (Allow Search)

Expression:

(http.user_agent contains "GPTBot") or
(http.user_agent contains "ClaudeBot") or
(http.user_agent contains "anthropic-ai") or
(http.user_agent contains "Google-Extended") or
(http.user_agent contains "CCBot") or
(http.user_agent contains "Meta-ExternalAgent") or
(http.user_agent contains "Bytespider") or
(http.user_agent contains "DeepSeekBot") or
(http.user_agent contains "xAI-Grok")

Action: Block

This blocks training bots while allowing PerplexityBot, ChatGPT-User, and other search/assistant bots.

Bot Classification Reference

Training Bots (18 bots) - Recommended: BLOCK

Bot Company Why Block
GPTBot OpenAI Trains GPT models
ClaudeBot Anthropic Trains Claude models
anthropic-ai Anthropic Bulk training crawler
Google-Extended Google Trains Gemini
CCBot Common Crawl Data sold to AI companies
Meta-ExternalAgent Meta Trains Llama
FacebookBot Meta AI training
Bytespider ByteDance Aggressive, ignores robots.txt
Baiduspider Baidu Trains Chinese LLMs
DeepSeekBot DeepSeek Trains DeepSeek models
cohere-ai Cohere Trains Cohere models
PanguBot Huawei Trains PanGu models
360Spider 360 Ignores robots.txt
Sogou Sogou Ignores robots.txt
ChatGLM-Spider Zhipu AI Ignores robots.txt
xAI-Grok xAI May disguise user agent
ImgBot OpenAI Image training
Applebot-Extended Apple Apple Intelligence training

AI Search Bots (6 bots) - Recommended: ALLOW

Bot Company Why Allow
PerplexityBot Perplexity AI search with citations
OAI-SearchBot OpenAI ChatGPT search feature
YouBot You.com AI search engine
iaskspider iAsk.Ai AI Q&A with sources
Kangaroo Bot Jina AI Multimodal AI search

AI Assistants (6 bots) - Recommended: ALLOW

Bot Company Why Allow
ChatGPT-User OpenAI Real-time browsing, cites sources
Claude-Web Anthropic Real-time citations
DuckAssistBot DuckDuckGo DuckDuckGo AI answers
MistralAI-User Mistral Le Chat citations
Perplexity-User Perplexity Real-time search
Amazonbot Amazon Alexa answers

Measuring Success

Key Metrics to Track

After implementing selective blocking:

  1. Bandwidth usage - Should decrease 30-50%
  2. Server load - CPU/memory should drop
  3. AI search referrals - Monitor for new traffic sources
  4. Content citations - Check if AI assistants cite you

Tools for Monitoring

  • Server logs: Look for bot user agents
  • Google Analytics: Check referral traffic from perplexity.ai, you.com
  • CheckAIBots: Verify your robots.txt configuration
  • Cloudflare Analytics: See blocked vs allowed bots

Common Questions

Should I allow PerplexityBot?

Pros:

  • Perplexity is growing as an AI search engine
  • They cite sources prominently
  • Can drive traffic to your site

Cons:

  • Some reports of aggressive crawling
  • Content used to generate AI answers that may reduce clicks

Verdict: Allow with monitoring. If you see aggressive behavior, switch to block.

Is ChatGPT-User different from GPTBot?

Yes, completely different:

Bot Purpose Your Benefit
GPTBot Train GPT models None
ChatGPT-User Fetch pages for user questions Traffic + citations

Block GPTBot, allow ChatGPT-User.

What about Google-Extended vs Googlebot?

Bot Purpose SEO Impact
Googlebot Search indexing Critical - never block
Google-Extended Train Gemini AI None - safe to block

Always allow Googlebot, consider blocking Google-Extended.

Will AI search engines become as important as Google?

Early signs suggest yes:

  • Perplexity growing 50%+ monthly
  • ChatGPT search feature expanding
  • Users increasingly prefer AI answers

Blocking all AI search now could hurt you later.

Strategy by Website Type

News Sites

Recommended: Block training, allow search

  • Training bots compete with your journalism
  • AI search can drive breaking news traffic

E-commerce

Recommended: Allow most AI bots

  • Product discovery via AI is growing
  • AI assistants can recommend your products

Personal Blogs

Recommended: Block training bots only

  • Your content shouldn't train commercial AI
  • AI search citations can boost visibility

SaaS/Documentation

Recommended: Allow assistants, consider blocking training

  • Users search for help via AI
  • Your docs appearing in AI answers helps users find you

Future Considerations

The AI bot landscape is evolving rapidly:

  • New bots emerge monthly - Review your rules quarterly
  • Regulations may change - EU AI Act and others may affect crawling
  • Business models shift - Some AI companies may start paying for content

Stay flexible. What's right today may change tomorrow.

Conclusion

A smart AI bot strategy isn't about blocking everything—it's about choosing what to allow based on value:

  1. Block training bots - They take without giving
  2. Allow search bots - They can drive traffic
  3. Allow assistants - They cite and can refer users

Use the configurations in this guide to implement selective blocking via robots.txt, server rules, or Cloudflare.

Check your current AI bot exposure with our free crawler checker and see exactly which bots can access your site.

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