What it does
ClaudeBot is Anthropic's training crawler. Content is copied into datasets used to train foundation models. Blocking costs you nothing in traffic today; allowing is a donation of your content to model weights with no citation or referral in return.
Anthropic documents robots.txt + Crawl-delay support and no-CAPTCHA-circumvention. Blocking by IP can break the opt-out (impedes robots.txt reads) — prefer robots directives.
Full UA: not captured in our July 2026 roster review — match log hits on the token ClaudeBot (case-insensitive substring) and verify by IP before acting.
How to verify a hit is really ClaudeBot
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 ClaudeBot in robots.txt:
# Block ClaudeBot site-wide
User-agent: ClaudeBot
Disallow: /# Explicitly allow ClaudeBot
User-agent: ClaudeBot
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 ClaudeBot?
ClaudeBot is Anthropic's training crawler. Content is copied into datasets used to train foundation models. Blocking costs you nothing in traffic today; allowing is a donation of your content to model weights with no citation or referral in return.
Does ClaudeBot respect robots.txt?
Yes — Anthropic documents robots.txt compliance for ClaudeBot (vendor docs reviewed July 2026).
How do I block ClaudeBot?
Add 'User-agent: ClaudeBot' followed by 'Disallow: /' to your robots.txt. Use the exact token — substring variants of other tokens will not match.