What is robots.txt for AI?
Robots.txt is a 30-year-old text file sitting at the root of your site. It was designed for search-engine spiders, but AI engines inherited the same protocol. Today it is the front door of your domain for every AI crawler that respects standards — which is most of them.
A bot that is disallowed at the door cannot read your pages, which means it cannot quote, summarize, or recommend them in AI answers. A bot that is allowed gets to read — but reading is still only step one of being cited.
The checker walks every line of your robots.txt against a list of 15 known AI agents and tells you, per bot, whether you currently let them in.
User-agent blocks
Each block targets one crawler. "User-agent: *" applies to anything without a more specific block. Most AI bots will pick up their own named block if present.
Allow / Disallow rules
Allow opens a path, Disallow closes one. Modern crawlers honor the longest, most specific matching rule — so order is less important than precision.
AI bots respect robots.txt (mostly)
Major AI crawlers — GPTBot, ClaudeBot, PerplexityBot, Google-Extended — publicly commit to honoring robots.txt. A small minority ignore it; for those, network-level controls are the only reliable answer.