Claude-User
Anthropic · Live retrieval · robots.txt token claude-user
2% of 30,177 measured domains disallow claude-user in robots.txt at the site root. Separately, and independently of robots.txt, 17.4% of 30,187 reachable domains refuse an AI crawler user agent at the network edge on two consecutive probes from different locations - a refusal the site's own robots.txt does not declare and its owner often has not chosen.
Measured 2026-10-06 by direct request to every domain in the corpus. Method: how this is measured. Reuse under CC BY 4.0 with attribution.
Cite as: Crawl Census, "Claude-User blocking rate", measured 2026-10-06. https://crawlcensus.com/bot/claude-user
What it is definition
Retrieves pages on demand when a Claude user's question needs live web content.
Claude-User is operated by Anthropic and classified here as live retrieval. These agents fetch a single URL because a user asked about it. Disallowing one means the assistant answers from an older copy or from someone else's summary instead of the live page. Several are documented as not bound by robots.txt, because the request is user-initiated rather than a crawl.
Disallowing claude-user stops the fetch that happens when a user asks Claude about one of your URLs. The answer still gets written, from an older copy or from a third party's description of the page, and you no longer control what it says.
- robots.txt token
- claude-user
- Operator
- Anthropic
- Purpose
- Live retrieval
- Honors robots.txt
- yes
- Documentation
- https://support.claude.com/en/articles/8896518-does-anthropic-crawl-data-from-the-web-and-how-can-site-owners-block-the-crawler
Identity on the wire exact string
Mozilla/5.0 (compatible; Claude-User/1.0; +Claude-User@anthropic.com)curl -A 'Mozilla/5.0 (compatible; Claude-User/1.0; +Claude-User@anthropic.com)' https://example.com/Replace the host with your own. A 403, a challenge page or an empty body means the edge is blocking the agent whatever robots.txt says.
How to allow it, how to block it robots.txt
User-agent: claude-user
Allow: /Absent any rule, the agent is already allowed, so this group only matters when your * group disallows something. Naming the agent replaces the * group for it entirely, so repeat here every disallow you still want to apply to it.
User-agent: claude-user
Disallow: /Disallowing claude-user stops the fetch that happens when a user asks Claude about one of your URLs. The answer still gets written, from an older copy or from a third party's description of the page, and you no longer control what it says.
Sites that block it 60 shown
See every measured domain that blocks Claude-User
This list is served from a cache rebuilt just now. It is discarded the moment a rescan records a policy change for this agent, so a site that has just changed its robots.txt will drop off it within one scan rather than waiting for the cache to expire.
Compare Anthropic
Anthropic runs 4 agents in this registry, and they do different jobs. Blocking one says nothing about the others.
Common questions answered
Does blocking Claude-User remove me from Claude?
Partly. Claude-User fetches a page only when a user asks about it, so disallowing it does not delist you from Claude. It does mean the answer is composed without your live page, from a stale copy or a third-party summary.
How do I verify Claude-User requests are genuine?
Anthropic publishes the address ranges its crawlers fetch from, linked from its crawler support article. Compare the source address of the request against that list. There is no reverse DNS name to check.
Check your own site free
See whether your robots.txt admits Claude-User today, and whether your edge agrees with it.