ClaudeBot: what it is, what it does with your content, and what blocking it costs
What ClaudeBot is
ClaudeBot collects pages to train future models. It does not decide whether Anthropic can cite you in an answer today — that is a different crawler with a different token. Blocking ClaudeBot is a decision about your content being learned from, not about your visibility.
Operator: Anthropic
robots.txt token: ClaudeBot
User-agent on the wire: Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko); compatible; ClaudeBot/1.0; [email protected]
Category: Model training
What blocking it actually costs
Your content is excluded from training future Claude models.
How to block ClaudeBot
Add this to your robots.txt:
User-agent: ClaudeBot
Disallow: /
The token must appear on its own User-agent: line. A named group replaces the User-agent: * group rather than adding to it, so anything you also want disallowed for this crawler has to be repeated inside its group.
How to allow ClaudeBot
User-agent: ClaudeBot
Allow: /
An explicit allow is worth writing even when you have no blanket block: it documents the decision, and it survives someone later adding a restrictive User-agent: * rule without thinking about AI crawlers.
robots.txt is not the only thing that can block it
A permissive robots.txt does not mean ClaudeBot can reach you. WAF rules, Cloudflare's bot-management settings, rate limits and country blocks all sit in front of robots.txt and answer first. A site whose robots.txt welcomes ClaudeBot and whose edge returns 403 to it is blocked in every way that matters — and nothing in robots.txt will tell you so.
This is the gap the AI Crawler Access Checker was built to close: it reads robots.txt and sends a real request carrying the crawler's user-agent, so you see what the crawler sees.
Official documentation
Anthropic documents ClaudeBot at https://support.anthropic.com/en/articles/8896518.
Common questions
- What user-agent does ClaudeBot send?
Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko); compatible; ClaudeBot/1.0; [email protected]- How do I block ClaudeBot?
Add a group to robots.txt naming the token exactly:
User-agent: ClaudeBot Disallow: /The group must name
ClaudeBoton its own line. AUser-agent: *group does not combine with a named one — under RFC 9309 the most specific matching group replaces the wildcard entirely, it does not inherit from it.- What does blocking ClaudeBot cost me?
Your content is excluded from training future Claude models.
- Can I tell a real ClaudeBot request from a fake one?
Not reliably. Anthropic does not publish verified IP ranges for ClaudeBot, so the user-agent string is the only signal, and anyone can send it. Treat robots.txt as a statement of policy rather than as enforcement.
Is ClaudeBot blocked on your site right now?
Reading your own robots.txt only answers half of it — a firewall rule can block ClaudeBot while robots.txt says it is welcome. The checker tests both.
Check your site free