HOW AI CRAWLERS READ YOUR SITE, AND HOW TO LET THEM

AI answers are built by crawlers, automated readers like OpenAI's GPTBot, Anthropic's ClaudeBot and Perplexity's PerplexityBot, that fetch pages from the open web so the models can learn from and cite them. Whether those crawlers can read your site is controlled mostly by one small file, your robots.txt, plus the same crawlability basics that have always governed Google. If you accidentally block them, or your site is slow and messy to crawl, you can be invisible to AI answers no matter how good your content is. This is the technical layer of AI SEO, and it is simpler than it sounds.

Who is actually reading your site

A handful of named crawlers do most of the AI reading, and they identify themselves in your server logs by a user-agent string. The main ones worth knowing:

• GPTBot, OpenAI's crawler, feeds ChatGPT. OpenAI documents it and its IP ranges publicly.
• OAI-SearchBot, OpenAI's crawler for its search features, distinct from the training crawler.
• ClaudeBot, Anthropic's crawler.
• PerplexityBot, Perplexity's crawler.
• Google-Extended, a control token that governs whether Google may use your content for its AI products, separate from normal Googlebot indexing.

You do not need to memorise every one. You need to know they exist, that they announce themselves, and that you can see them in your logs and decide, per crawler, whether they are welcome.

The file that decides everything: robots.txt

robots.txt is a plain text file at the root of your domain that tells crawlers what they may and may not fetch. It has governed Googlebot for decades, and the AI crawlers respect it too. This is where a lot of businesses accidentally shoot themselves in the foot.

The trap is this. Plenty of sites, worried about AI "stealing" their content, added rules to block GPTBot and the rest. That is a legitimate choice for some publishers. But understand the trade. Blocking every AI crawler does not just stop them training on you. It removes you from the answers your buyers increasingly rely on to shortlist suppliers. You cannot be cited in an answer built from a page the engine was never allowed to read.

So decide deliberately, not by default or by copying someone's paranoid config. If being named in AI answers is worth more to you than the content-protection concern, and for most service and B2B businesses trying to get found, it is, then let the answer-building crawlers in. Check your robots.txt actually allows them, because a surprising number of sites are blocking the very engines they want to appear in without realising it.

llms.txt: the new convention, in perspective

You may have heard of llms.txt. It is an emerging proposal for a file, also at your domain root, that points AI tools to your most important, cleanest content in a simple, machine-friendly form, a curated map of what matters on your site.

Here is the honest status. It is a sensible idea and adoption is growing, but it is a convention, not a rule the major engines universally obey yet. Treat it as a low-cost nice-to-have: if you can add a clean llms.txt pointing at your key pages, do, it cannot hurt and may increasingly help. Do not treat it as the thing that makes or breaks your AI visibility, because today it is not. The fundamentals matter far more.

The fundamentals still decide it

Under the new acronyms, the boring truth is that a site which is easy for Google to crawl is easy for AI crawlers to read, because they work the same way. So the old technical SEO checklist is most of the AI-crawler checklist too.

Be fast and reachable. A crawler on a budget will not wait around for a slow site or fight through errors. Speed and uptime are crawlability.

Render your content in HTML, not just JavaScript. Content that only appears after heavy client-side scripting is harder for crawlers to read reliably. The important text should be in the page a crawler fetches, not assembled only in a browser.

Keep a clean sitemap and sane internal links. Help crawlers find everything that matters and understand how it connects. A clear structure is as useful to a machine as to a reader.

Do not hide your best facts in images or PDFs. A model reads text. A key claim trapped in a picture with no caption, alt text or table is invisible to it. This ties straight into making your facts machine-liftable, which I cover in structured data for AI search.

None of that is new work if your SEO house is already in order. That is the point. The technical layer of AI SEO is largely the technical layer of SEO, pointed at a new set of readers who happen to be stricter about clarity.

Where this sits in the bigger picture

Crawlability is necessary but not sufficient. Letting the crawlers in gets you read. Being answer-first, specific and genuinely authoritative gets you cited. You need both, and the full four-lever picture is in what is AI SEO. Think of crawler access as the door: it does not guarantee you win, but if it is locked, nothing else you do matters.

Start by checking you are even readable

Most businesses have never looked at whether AI crawlers can reach them, let alone whether they get cited. So start concrete. Check your robots.txt is not quietly blocking the engines you want to appear in, then get a baseline of how often AI actually names you against your competitors.

That baseline is where our AI Search product begins, with a free scan. It is the honest first step: confirm the machines can read you, see how often they name you today, and then decide what closing the gap is worth.