Claude-User
Anthropic •
Since 2024
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What is Claude-User?
Claude-User is the user agent employed when Anthropic's Claude assistant fetches web pages in real-time during user conversations. This bot is triggered by explicit user requests for current web information and does not perform bulk crawling or data collection for training purposes. It respects robots.txt directives and operates transparently, allowing website owners to distinguish between user-initiated browsing and training data collection by Anthropic's other crawlers.
User Agent String
Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; Claude-User/1.0; [email protected])
How to Control Claude-User
Block Completely
To prevent Claude-User from accessing your entire website, add this to your robots.txt file:
# Block Claude-User
User-agent: Claude-User
Disallow: /
Block Specific Directories
To restrict access to certain parts of your site while allowing others:
User-agent: Claude-User
Disallow: /admin/
Disallow: /private/
Disallow: /wp-admin/
Allow: /public/
Set Crawl Delay
To slow down the crawl rate (note: not all bots respect this directive):
User-agent: Claude-User
Crawl-delay: 10
How to Verify Claude-User
Verification Method:
Verify requests originate from Anthropic IP ranges
Verify requests originate from Anthropic IP ranges
Learn more in the official documentation.
⚠️ AI Training Notice
This bot may collect and use your website content for AI model training. Consider whether you want your content used for this purpose before allowing access.
This bot may collect and use your website content for AI model training. Consider whether you want your content used for this purpose before allowing access.
Detection Patterns
Multiple ways to detect Claude-User in your application:
Basic Pattern
/Claude\-User/iStrict Pattern
/^Mozilla/5\.0 AppleWebKit/537\.36 \(KHTML, like Gecko; compatible; Claude\-User/1\.0; \+Claude\-User@anthropic\.com\)$/Flexible Pattern
/Claude\-User[\s\/]?[\d\.]*?/iVendor Match
/.*Anthropic.*Claude\-User/iImplementation Examples
// PHP Detection for Claude-User
function detect_claude_user() {
$user_agent = $_SERVER['HTTP_USER_AGENT'] ?? '';
$pattern = '/Claude\\-User/i';
if (preg_match($pattern, $user_agent)) {
// Log the detection
error_log('Claude-User detected from IP: ' . $_SERVER['REMOTE_ADDR']);
// Set cache headers
header('Cache-Control: public, max-age=3600');
header('X-Robots-Tag: noarchive');
// Optional: Serve cached version
if (file_exists('cache/' . md5($_SERVER['REQUEST_URI']) . '.html')) {
readfile('cache/' . md5($_SERVER['REQUEST_URI']) . '.html');
exit;
}
return true;
}
return false;
}
# Python/Flask Detection for Claude-User
import re
from flask import request, make_responsedef detect_claude_user():
user_agent = request.headers.get('User-Agent', '')
pattern = r'Claude-User'
if re.search(pattern, user_agent, re.IGNORECASE):
# Create response with caching
response = make_response()
response.headers['Cache-Control'] = 'public, max-age=3600'
response.headers['X-Robots-Tag'] = 'noarchive'
return True
return False# Django Middleware
class ClaudeUserMiddleware:
def __init__(self, get_response):
self.get_response = get_response
def __call__(self, request):
if self.detect_bot(request):
# Handle bot traffic
pass
return self.get_response(request)
// JavaScript/Node.js Detection for Claude-User
const express = require('express');
const app = express();// Middleware to detect Claude-User
function detectClaudeUser(req, res, next) {
const userAgent = req.headers['user-agent'] || '';
const pattern = /Claude-User/i;
if (pattern.test(userAgent)) {
// Log bot detection
console.log('Claude-User detected from IP:', req.ip);
// Set cache headers
res.set({
'Cache-Control': 'public, max-age=3600',
'X-Robots-Tag': 'noarchive'
});
// Mark request as bot
req.isBot = true;
req.botName = 'Claude-User';
}
next();
}app.use(detectClaudeUser);
# Apache .htaccess rules for Claude-User# Block completely
RewriteEngine On
RewriteCond %{HTTP_USER_AGENT} Claude\-User [NC]
RewriteRule .* - [F,L]# Or redirect to a static version
RewriteCond %{HTTP_USER_AGENT} Claude\-User [NC]
RewriteCond %{REQUEST_URI} !^/static/
RewriteRule ^(.*)$ /static/$1 [L]# Or set environment variable for PHP
SetEnvIfNoCase User-Agent "Claude\-User" is_bot=1# Add cache headers for this bot
<If "%{HTTP_USER_AGENT} =~ /Claude\-User/i">
Header set Cache-Control "public, max-age=3600"
Header set X-Robots-Tag "noarchive"
</If>
# Nginx configuration for Claude-User# Map user agent to variable
map $http_user_agent $is_claude_user {
default 0;
~*Claude\-User 1;
}server {
# Block the bot completely
if ($is_claude_user) {
return 403;
}
# Or serve cached content
location / {
if ($is_claude_user) {
root /var/www/cached;
try_files $uri $uri.html $uri/index.html @backend;
}
try_files $uri @backend;
}
# Add headers for bot requests
location @backend {
if ($is_claude_user) {
add_header Cache-Control "public, max-age=3600";
add_header X-Robots-Tag "noarchive";
}
proxy_pass http://backend;
}
}
Should You Block This Bot?
Recommendations based on your website type:
| Site Type | Recommendation | Reasoning |
|---|---|---|
| E-commerce | Limit Access | Protect pricing and inventory data from AI training |
| Blog/News | Consider Blocking | Your content may be used for AI training without compensation |
| SaaS Application | Block | No benefit for application interfaces; preserve resources |
| Documentation | Selective | Allow for public docs, block for internal docs |
| Corporate Site | Limit | Allow for public pages, block sensitive areas like intranets |
Advanced robots.txt Configurations
E-commerce Site Configuration
User-agent: Claude-User
Crawl-delay: 5
Disallow: /cart/
Disallow: /checkout/
Disallow: /my-account/
Disallow: /api/
Disallow: /*?sort=
Disallow: /*?filter=
Disallow: /*&page=
Allow: /products/
Allow: /categories/
Sitemap: https://example.com/sitemap.xml
Publishing/Blog Configuration
User-agent: Claude-User
# Blocking AI training bot
Disallow: /
SaaS/Application Configuration
User-agent: Claude-User
Disallow: /app/
Disallow: /api/
Disallow: /dashboard/
Disallow: /settings/
Allow: /
Allow: /pricing/
Allow: /features/
Allow: /docs/
Quick Reference
User Agent Match
Claude-UserRobots.txt Name
Claude-UserCategory
aiRespects robots.txt
Yes
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