User-triggered fetchers · Anthropic

Claude-User

Fetches a page when a Claude user asks about it. It does not crawl on its own.

Operator: Anthropic
Purpose: Live user request. Fetchers that load a page because a person asked an assistant about it. Blocking one means the assistant can’t open your pages on request.
robots.txt token: Claude-User
User agent: Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; Claude-User/1.0; +Claude-User@anthropic.com)
Documentation: support.claude.com/en/articles/8896518

Block Claude-User

Add a group naming it to /robots.txt. Compliant crawlers stop before requesting any page. A firewall rule on the user agent is the only way to enforce it against crawlers that ignore robots.txt.

User-agent: Claude-User
Disallow: /

Allow Claude-User when everything else is blocked

A group naming the bot wins over User-agent: *, so an explicit allow lets it in while your catch-all rules stay in place.

User-agent: Claude-User
Allow: /

User-agent: *
Disallow: /

Does Claude-User reach your site?

The checker applies your robots.txt the way Claude-User does, then requests your page with the user agent above, alongside 29 other bots.

Also run by Anthropic: Claude-SearchBot, ClaudeBot.

Other user-triggered fetchers: ChatGPT-User, Perplexity-User, MistralAI-User, Meta-ExternalFetcher.

Build a complete file with the robots.txt generator.