anthropic-ai user agent
Operated by Anthropic
anthropic-ai is an older robots.txt token associated with Anthropic's training data collection.
The anthropic-ai bot at a glance
- anthropic-ai is operated by Anthropic and collects public web pages that may be used to train AI models.
- The robots.txt token for anthropic-ai is anthropic-ai.
- Blocking an AI training crawler has no effect on Google or Bing rankings.
- anthropic-ai robots.txt support: Not documented.
- Recommendation for Generative Engine Optimization (GEO): Your choice.
What is anthropic-ai?
anthropic-ai appears in many robots.txt files from 2023 onward, when it was listed as an Anthropic training token. Anthropic’s current crawler page names ClaudeBot instead.
Keeping an anthropic-ai rule is harmless, but a ClaudeBot rule is what controls Anthropic training today.
Should you block anthropic-ai?
Blocking anthropic-ai is a business decision: it protects your content but can lower how well AI products know your brand.
| Effect on search rankings | Blocking an AI training crawler has no effect on Google or Bing rankings. |
|---|---|
| Effect on AI visibility | Blocking keeps your future pages out of that company's training data, so its models may know less about your brand over time. It does not remove you from that company's AI search, which uses a separate bot. |
| Follows robots.txt | Not documented |
| Recommendation | Your choice |
How to block or allow anthropic-ai
Put the robots.txt rule in the file at the root of every domain and subdomain, for example https://example.com/robots.txt. The token anthropic-ai is matched case-insensitively. robots.txt alone may not stop anthropic-ai, so add the Nginx, Apache or Cloudflare rule as well.
robots.txt: block
# Block anthropic-ai
User-agent: anthropic-ai
Disallow: /robots.txt: allow
# Allow anthropic-ai
User-agent: anthropic-ai
Allow: /robots.txt: partial
# Keep anthropic-ai out of private areas only
User-agent: anthropic-ai
Disallow: /wp-admin/
Disallow: /cart/
Disallow: /checkout/
Disallow: /my-account/
Allow: /Nginx
# Nginx: return 403 to anthropic-ai
if ($http_user_agent ~* "(anthropic\-ai)") {
return 403;
}Apache
# Apache .htaccess: return 403 to anthropic-ai
RewriteEngine On
RewriteCond %{HTTP_USER_AGENT} (anthropic\-ai) [NC]
RewriteRule .* - [F,L]Cloudflare WAF
# Cloudflare > Security > WAF > Custom rule, action: Block
(http.user_agent contains "anthropic-ai")How to verify real anthropic-ai traffic
Anthropic publishes no IP list or reverse DNS pattern for anthropic-ai, so the user agent cannot be verified. Anyone can send the same string. Rate-limit unusual volume instead of trusting the name.
How to find anthropic-ai in your server logs
Search the web server access log for the token. The command below counts anthropic-ai requests per URL on Nginx or Apache.
grep -i "anthropic-ai" access.log | awk '{print $7}' | sort | uniq -c | sort -rn | head -20For a full report per AI bot, upload the log to the AI Log File Analyzer, a free tool by Justin Hà.
anthropic-ai FAQ
anthropic-ai uses the robots.txt token "anthropic-ai". Anthropic does not publish a full user-agent string, so match the token inside the User-Agent header.
Anthropic has not documented how anthropic-ai treats robots.txt. Add a robots.txt rule and back it with a server rule if the traffic matters to you.
Blocking an AI training crawler has no effect on Google or Bing rankings. Blocking keeps your future pages out of that company's training data, so its models may know less about your brand over time. It does not remove you from that company's AI search, which uses a separate bot.
Add two lines to the robots.txt file at the root of each domain and subdomain: "User-agent: anthropic-ai" followed by "Disallow: /". The token is case-insensitive. Changes can take up to 24 hours to be picked up.
Not reliably. Anthropic publishes no IP list or reverse DNS pattern for anthropic-ai, so anyone can send the same user agent. Rate-limit unusual volume instead of trusting the name.
Search your server access log for "anthropic-ai", for example with: grep -i "anthropic-ai" access.log. The AI Log File Analyzer by Justin Hà counts visits per AI bot from an uploaded log file.
Sources: Public bot registry. Last reviewed by Justin Hà.
See which of these bots actually reach your website
The AI Log File Analyzer by Justin Hà counts visits from GPTBot, ClaudeBot, PerplexityBot and other AI crawlers in your server log, for free. The GEO Technical Package sets up robots.txt, llms.txt and crawler access for AI search.
