Claude-User fetches a page when a person using Claude asks about it or Claude searches the web to answer them. Fetches a page because a person asked the assistant about it right now; blocking it makes you unreadable at the moment it matters.
Claude-User fetches a page when a person using Claude asks about it or Claude searches the web to answer them. It is the read that happens at the moment a buyer is asking.
User-initiated fetch: fetches a page because a person asked the assistant about it right now; blocking it makes you unreadable at the moment it matters.
User-agent string:
Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; Claude-User/1.0; +Claude-User@anthropic.com)robots.txt token: Claude-User. Documented: fetches on a user's behalf.
Anthropic documents its outbound range — 160.79.104.0/21 and 2607:6bc0::/48 — at https://platform.claude.com/docs/en/api/ip-addresses. A request from outside it is not Claude-User.
AI bot verifier → checks an IP and user-agent against the published ranges and reverse DNS, free.
Blocking Claude-User makes your site unreadable to Claude exactly when someone is asking about you. Allow it if you want Claude to describe you from your own pages.
Check your site: the AI Crawler Access Check reads your robots.txt for Claude-User and the other AI crawlers and fetches your homepage with each one's real user-agent — the CDN challenge that robots.txt cannot show.
Blocking Claude-User makes your site unreadable to Claude exactly when someone is asking about you. Allow it if you want Claude to describe you from your own pages.
Add a group for it: User-agent: Claude-User on one line and Allow: / on the next. If a User-agent: * group has a Disallow, the named group takes precedence for Claude-User.
User-agent: Claude-User then Disallow: /. Documented: fetches on a user's behalf.
Anthropic documents its outbound range — 160.79.104.0/21 and 2607:6bc0::/48 — at https://platform.claude.com/docs/en/api/ip-addresses. A request from outside it is not Claude-User.
The free crawler check reads your robots.txt per bot and fetches your homepage with each one's real user-agent.