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Claude-Web user agent

Operated by Anthropic · Live answers · Answering you

robots.txt token
Claude-Web

Claude-Web identifies itself with the token Claude-Web. That is the case-insensitive substring to grep for in access logs, and the exact name to put after User-agent: in robots.txt. It fetches a page live, at the moment a user asks something.

Allow or block Claude-Web in robots.txt

Robots.txt applies the most specific matching group, so a group naming Claude-Web overrides your User-agent: * rules for this bot alone.

Allow
User-agent: Claude-Web
Allow: /
Block
User-agent: Claude-Web
Disallow: /

What blocking costs you: Claude.ai can't fetch your pages when users share or ask about a URL.

To see which AI crawlers your robots.txt allows right now, run your domain through the AI crawler access checker. To check whether AI answers actually cite you, use the AI citation checker.

Anthropic's other crawlers

Blocking one Anthropic bot does not block the others — each token is a separate group.

Anthropic's own documentation: https://support.anthropic.com/en/articles/8896518

FAQ

What is the Claude-Web user agent?
Claude-Web announces itself with the User-Agent token "Claude-Web". That token is the case-insensitive substring to match in server logs and the exact name to put after "User-agent:" in robots.txt. Anthropic does not publish one fixed full string, so match on the token rather than the whole line.
Who operates Claude-Web and what does it collect?
Claude-Web is run by Anthropic and fetches a page live, at the moment a user asks something. In the AI picture that puts it under "Answering you": A live user prompt made an AI fetch your page to answer.
How do I block Claude-Web?
Add a robots.txt group naming the token exactly: User-agent: Claude-Web followed by Disallow: /. Robots.txt matches the most specific group, so a Claude-Web group overrides whatever your User-agent: * group says. Claude.ai can't fetch your pages when users share or ask about a URL.
Should I block Claude-Web?
That depends on what you lose. Claude.ai can't fetch your pages when users share or ask about a URL. Sites chasing AI citations usually keep the live-answer and AI-search bots open and make a separate decision about the training crawlers. Run your domain through the AI crawler access checker to see which ones your robots.txt lets in today.
Can Claude-Web be spoofed?
Yes. A User-Agent header is self-reported, so any scraper can claim to be Claude-Web. The token is fine for reporting and for robots.txt, but if you are rate-limiting or firewalling on it, verify the request IP against Anthropic's published ranges before you trust the name.

Paste a full User-Agent line and identify any crawler with the AI bot user agent list and lookup, or see every token side by side.