Claude-User
Fetches a site when a person asks Claude a question that needs web retrieval, so Claude can answer from the page and cite it.
Where this comes from
- Documented by the vendor. Source: support.claude.com
- Honours robots.txt. Published addresses: claude.com/crawling/bots.json.
- Counted in the readiness score. It can keep a site out of AI search or answers, so a block costs points.
In the top 1,000 websites
- 12% block it in robots.txt (68 of the 569 sites with a robots.txt), as of 2026-10-12.
- Method, limits and the full data: the October 2026 study of the top 1,000 websites.
What blocking it costs
A rule may not stop it: Claude-User fetches a page because a person asked about it, and its vendor says such fetches can bypass robots.txt. Where it does honour the rule, the assistant cannot read your page when asked. The score counts it, so a block costs points.
The robots.txt lines
To let it in (a group that names the crawler replaces any wildcard rules for it, so this also lifts a User-agent: * block):
User-agent: Claude-User
Allow: /To keep it out:
User-agent: Claude-User
Disallow: /A rule in robots.txt is a request. Anthropic says this crawler honours it. The robots.txt generator writes a whole file with the same split: block the training crawlers, keep the search and answer crawlers.
Also from Anthropic
ClaudeBot· Training onlyClaude-SearchBot· AI search indexClaude-Web· Retired tokenanthropic-ai· Retired token
Does Claude-User get through on your site?
Run the free check: it reads your robots.txt against all 51 crawlers and tells you which ones can read you, and what to change.