Claude-Web

Operator

Anthropic PBC

Type

AI Search Crawler

Official page

support.claude.com

robots.txt token

Claude-Web

In Vireo

Excluded, reported under AI crawlers

What it does

Claude-Web is an AI-related agent operated by Anthropic. It's currently unclear exactly what it's used for, since there's no official documentation. If you can provide more detail, please contact us.

ai.robots.txt describes its function as: Undocumented AI Agents

Source: ai.robots.txt.

User agent

Requests from Claude-Web carry a user agent like this:

Mozilla/5.0 (compatible; Claude-Web/1.0; +https://www.anthropic.com)

Device Detector identifies it with this pattern (a case-insensitive regular expression):

Claude-Web

Anyone can put any name in a user agent. Where the operator publishes IP ranges, checking the request's address against them is the way to confirm a visit is genuine.

How to block or allow Claude-Web

Add a group for its token to the robots.txt file at the root of your site. To keep it out of the whole site:

User-agent: Claude-Web
Disallow: /

To let it crawl everything, use an empty Disallow: or Allow: / instead. WordPress serves a virtual robots.txt that many SEO plugins let you edit. A real robots.txt file uploaded to the site root takes its place.

robots.txt is a request, so it only works on crawlers that honour it. A bot that ignores it has to be blocked at the server or firewall, by user agent or IP address.

How Vireo counts Claude-Web

Vireo keeps requests from Claude-Web out of your pageviews and visitors and counts them on its bot report under AI crawlers, so you can see how much it left out rather than wonder why your server logs show more traffic.

Because it's an AI crawler, its requests also count toward the pages AI crawlers took, which Vireo shows next to the readers AI assistants sent back. See how the AI assistants card works.

Checked by running Vireo Analytics' own bot filter over Claude-Web's user agents.

Sources

• Claude-Web information page (support.claude.com)
• Matomo Device Detector, bots.yml (LGPL-3.0)
• ai.robots.txt (MIT)