Anthropic
Operated by Anthropic
ClaudeBotAbout this crawler
Anthropic is Anthropic's model training crawler. Collects page content that may be used to train or improve a model. Nobody is waiting on the other end, and nothing is cited back at the time of the visit.
A request from Anthropic usually means the page content is being collected and may be used to train or improve a model, and nobody is reading it right now.
User agent
Match on the token, not the whole header. Operators change version numbers and the surrounding text freely, so a substring match on the token is the only stable rule.
Mozilla/5.0 (compatible; ClaudeBot/1.0; +https://www.anthropic.com/claudebot)
Typical shape. The exact header varies by operator and version.
Blocking it in robots.txt
User-agent: ClaudeBot Disallow: /
robots.txt is a request, not enforcement. Well behaved crawlers honour it; nothing stops one that does not.
Verifying a request really came from Anthropic
Scrapers routinely borrow a well known crawler's user agent to slip past rate limits. Checking takes three pieces.
1. User agent
What the request claims to be. It is a plain header that anyone can set, so on its own it proves nothing.
2. Request IP
The address the request actually arrived from. Your server sees it directly, and it cannot be set by the caller the way a header can.
3. Range check
The operator publishes the IP ranges this crawler uses, as a file anyone can fetch. A request is genuine only if the address it came from falls inside one of those ranges.
Zenovay refreshes the list from the operator's own file and checks each request against it.
Sample published ranges
A sample, not the full list. The operator's file is the authority and it changes.
Published range file: https://claude.com/crawling/bots.json
More from Anthropic
Is Anthropic allowed on your site?
Zenovay reads your robots.txt and llms.txt and shows, crawler by crawler, which AI products you currently allow and which you block. It also tracks the AI assistants that send you real visitors, and ties those visits to revenue.
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