What it does
Claude-User is Anthropic's user action crawler. A live fetch made because a human asked the assistant about your page right now. Closest thing to a real visitor; several of these (Perplexity-User, meta-externalfetcher) ignore robots.txt by design because the request is user-initiated.
Fetches pages when an individual Claude user asks a question.
Full UA: not captured in our July 2026 roster review — match log hits on the token Claude-User (case-insensitive substring) and verify by IP before acting.
How to verify a hit is really Claude-User
Verification method (July 2026): Published IP list: https://claude.com/crawling/bots.json (fetched live 2026-07-19)
User-agent strings are freely spoofed, so a UA match alone proves nothing. Confirm the source IP belongs to Anthropic — published IP-range JSON where available, otherwise RDAP/rDNS on the IP. Full method: verify by IP.
Allow or block in robots.txt
Match the exact token Claude-User in robots.txt:
# Block Claude-User site-wide
User-agent: Claude-User
Disallow: /# Explicitly allow Claude-User
User-agent: Claude-User
Allow: /For the allow-search-block-training combined pattern (and the Allow-directive gotcha that silently kills carve-outs), see the robots.txt guide.
Vendor documentation: https://support.claude.com/en/articles/8896518-does-anthropic-crawl-data-from-the-web-and-how-can-site-owners-block-the-crawler
Frequently asked questions
What is Claude-User?
Claude-User is Anthropic's user action crawler. A live fetch made because a human asked the assistant about your page right now. Closest thing to a real visitor; several of these (Perplexity-User, meta-externalfetcher) ignore robots.txt by design because the request is user-initiated.
Does Claude-User respect robots.txt?
Anthropic claims Claude-User respects robots.txt, but compliance is not independently confirmed.
How do I block Claude-User?
Add 'User-agent: Claude-User' followed by 'Disallow: /' to your robots.txt. Use the exact token — substring variants of other tokens will not match.