Who runs it
Anthropic. It names itself with the token Claude-SearchBot. Anthropic doesn't publish a full user agent string for it.
What it does
It navigates the web to improve search result quality for users. Anthropic says blocking it prevents the system from indexing your content for search optimization.
Renders JavaScript
Not yet observed. Anthropic doesn't say whether Claude-SearchBot runs scripts, and this site hasn't recorded a verified visit yet.
How to verify it
Match the visiting address against Anthropic's published list, the same one that covers ClaudeBot and Claude-User.
robots.txt
Rules under User-agent: Claude-SearchBot apply to it, under Anthropic's general statement that its machines honor industry standard robots.txt directives. Anthropic documents no exception.
Questions
If I block ClaudeBot, is Claude-SearchBot blocked too?
No. Each of Anthropic's machines has its own token.