Operated by Anthropic
The main crawler for Anthropic. It scrapes the web to build the training dataset for the Claude family of AI models.
The main crawler for Anthropic. It scrapes the web to build the training dataset for the Claude family of AI models.
ClaudeBot is an AI data-collection crawler operated by Anthropic. It harvests web content to build or expand training datasets for large language models (LLMs). Unlike search crawlers, ClaudeBot does NOT influence your page ranking in any search engine. The user-agent string ClaudeBot can be safely blocked via robots.txt, meta tags (noai), or the emerging llms.txt standard without any SEO penalty. Robots.txt is voluntary; for hard enforcement, combine it with server-level IP blocking.
User-agent: ClaudeBot / Disallow: / without any SEO penalty. This is the recommended approach if you want to opt out of Anthropic's LLM training datasets.<code>User-agent: ClaudeBot</code> — Matching is case-insensitive. Robots.txt is fetched from the root of each subdomain separately.
ClaudeBot is verifiable via reverse-DNS lookup on the crawling IP addresses. You can safely allow it unless you have a specific reason to block (e.g., AI training opt-out or SEO tool visibility).Understanding ClaudeBot's purpose helps you decide whether to allow or block it.
ClaudeBot. This is the exact string you must use in robots.txt, Nginx, Apache, or Cloudflare firewall rules to target this bot. User-agent matching in robots.txt is case-insensitive, but the string must be spelled correctly. You can verify that a request genuinely comes from ClaudeBot by performing a reverse-DNS lookup on the source IP — legitimate bots resolve back to their operator's domain.ClaudeBot is verifiable via reverse-DNS lookup on the crawling IP addresses. You can safely allow it unless you have a specific reason to block (e.g., AI training opt-out or SEO tool visibility).User-agent: ClaudeBot / Disallow: / without any SEO penalty. This is the recommended approach if you want to opt out of Anthropic's LLM training datasets./robots.txt file:
User-agent: ClaudeBot Disallow: /This instructs ClaudeBot not to crawl any path on your site. The Disallow: / directive covers the entire domain including subfolders. To only block specific sections, replace / with the path (e.g.,
Disallow: /blog/). Note: robots.txt is publicly readable — any bot or human can inspect it at yourdomain.com/robots.txt.ClaudeBot (case-insensitive grep: grep -i "ClaudeBot" /var/log/nginx/access.log). You can also check Google Search Console → Coverage → Crawl Stats for Googlebot variants. For ClaudeBot specifically, filter by user-agent in your log analysis tool (GoAccess, AWStats, etc.).User-agent: ClaudeBot Crawl-delay: 10(10 second delay between requests).
Disallow: / you can restrict ClaudeBot to specific paths:
User-agent: ClaudeBot Disallow: /private/ Disallow: /staging/ Allow: /This allows ClaudeBot everywhere except the listed paths. Path matching in robots.txt uses prefix matching —
Disallow: /private/ blocks /private/page.html but NOT /public/private/.<meta name="ClaudeBot" content="noai, noimageai, noindex"> to your pages.
2. Add a llms.txt file at your domain root (emerging standard).
3. Use Cloudflare WAF or Nginx to return 403 for this user-agent.
4. Consider IP blocklists for Anthropic's known crawler IP ranges.<meta name="ClaudeBot" content="noindex">
• **X-Robots-Tag HTTP header**: X-Robots-Tag: noai, noimageai
• **llms.txt**: Add a /llms.txt file (similar to robots.txt but for LLMs)
• **Server block**: Return 403 or 429 for this user-agent via WAF or Nginx
Using multiple layers provides the strongest protection.