Google and ChatGPT are fundamentally different systems. A website can rank on page one of Google and score in the bottom 20% on AI search visibility. Fixing your Google rankings doesn't fix your ChatGPT visibility. They require different signals.
The good news: the reasons are well-understood. Most sites are invisible to ChatGPT for one or more of the following nine reasons – and each one has a clear fix. The free audit at the top of this page identifies which apply to your site in 60 seconds.
| # | Reason | Impact | Fix time |
|---|---|---|---|
| 1 | AI crawlers blocked in robots.txt | Critical | 1 hour |
| 2 | No llms.txt file | Critical | 1–2 hours |
| 3 | Missing schema markup | Critical | 1–3 days |
| 4 | Content not formatted for AI extraction | High | 1–2 weeks |
| 5 | No answer-first content structure | High | 1–2 weeks |
| 6 | Weak authority signals | High | Ongoing |
| 7 | No named author or credentials | High | 1–2 days |
| 8 | Inconsistent business information | Medium | 1 day |
| 9 | No third-party citations or mentions | Medium | Ongoing |
| 10 | Slow or inaccessible site | Medium | Variable |
AI crawlers are blocked in your robots.txt
ChatGPT uses a crawler called GPTBot to read websites. Perplexity uses PerplexityBot. Claude uses ClaudeBot. If any of these are blocked in your robots.txt file – which happens commonly after a security update, a CMS migration, or a plugin that sets aggressive crawl rules – AI engines literally cannot read your site. You can have the best content in the world and be completely invisible.
This is the single most common reason businesses are invisible to ChatGPT, and the easiest to fix. Check your robots.txt file at yourdomain.com/robots.txt right now. If you see Disallow: / under GPTBot, ClaudeBot or PerplexityBot – that's the problem.
You don't have an llms.txt file
llms.txt is a plain-text file placed at the root of your website – yourdomain.com/llms.txt – that tells AI engines what your site is, what it does, and which pages matter most. It works similarly to robots.txt, but specifically for AI systems rather than search engine crawlers.
Without an llms.txt file, AI engines have to guess what your site is about from whatever they can scrape. They'll often guess wrong, assign you to the wrong category, or skip you entirely in favour of sites that have clearly declared their purpose. 63% of websites don't have one – which means fixing this alone puts you ahead of most of your competitors.
/llms.txt that states: what your business does, your key services, your location(s), and links to your most important pages. Keep it under 500 words. Update it when your services change.Your site has no schema markup
Schema markup is structured data – code added to your pages that tells AI engines (and Google) what your content means, not just what it says. Without schema, AI engines have to infer what your business is from your text, which is unreliable. With schema, you explicitly state your business type, services, credentials, location, and opening hours in a machine-readable format.
The most important schema types for AI visibility are: Organisation (who you are), LocalBusiness (where you operate), Service (what you offer), Person (named practitioners), and FAQ (questions and answers on your pages). Each one adds a layer of structured information that AI engines can reliably extract and cite.
Your content isn't structured for AI extraction
ChatGPT cites content it can extract as a direct, self-contained answer. Most websites are written for humans scanning a page – long paragraphs, buried information, SEO-optimised but answer-light. AI engines struggle to extract a citable response from this format.
The format AI engines prefer is "answer-first": the direct answer stated in the first sentence, followed by supporting detail. "How long does conveyancing take? The process typically takes 8 to 12 weeks" is citable. "At our firm, we pride ourselves on handling conveyancing with care" is not. The most reliably cited content type is the FAQ – a question as a heading, followed by a direct 2–4 sentence answer. Combined with FAQ schema markup (reason 3), a well-structured FAQ section becomes explicitly machine-readable and one of the strongest citation targets on any page.
Your website has no named author or practitioner
For content touching health, finance, legal or professional advice, AI engines apply a higher credibility threshold – known in SEO as E-E-A-T (Experience, Expertise, Authoritativeness, Trustworthiness). Content published anonymously, without a named author or verifiable credentials, is significantly less likely to be cited in AI responses.
This affects professional service businesses disproportionately. A therapy practice without a named therapist, an accounting firm without named qualified accountants, a law firm without named solicitors – all of these look less credible to AI than the same businesses with clear professional attribution. The fix is fast and the impact is meaningful.
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Weak or missing authority signals
AI engines don't just look at your website in isolation. They evaluate how credible your site is across the web. The signals they weight most heavily are: third-party mentions (other websites citing or referencing you), consistent presence across authoritative platforms (industry directories, professional associations, press coverage), and brand co-citations (your name appearing alongside trusted names in your category).
A site with strong Google rankings but no third-party mentions will often underperform in AI search. AI engines treat verifiability as a proxy for trustworthiness. If no other credible source mentions you, AI hedges its bets and cites a source that has been mentioned.
Inconsistent business information across the web
AI engines cross-reference your business information across multiple sources. If your business name, address, phone number or description is inconsistent between your website, Google Business Profile, social profiles and directory listings, AI engines treat this as a credibility signal against you. Inconsistency implies unreliability.
This is a more significant issue than it sounds for businesses that have moved premises, changed names, rebranded, or have multiple trading names. Every inconsistency is a small reduction in AI credibility score.
No third-party citations or brand mentions
Being mentioned by name on credible third-party websites is one of the strongest signals AI engines use. It's the online equivalent of a reference – another source vouching for your existence and credibility. Press coverage, guest posts, podcast appearances, award listings, case study features – all of these generate citations that AI engines read and weight.
The contrast with Google SEO is important here. Google cares about backlinks (links pointing to you). AI engines care more about citations – your name and description appearing in context, even without a link. A mention in a relevant industry article carries weight even if it doesn't link to your site.
Your site is slow, broken or hard to access
AI crawlers are less patient than human visitors. A site that takes more than a few seconds to load, returns server errors, has a large proportion of broken internal links, or blocks crawlers with CAPTCHA or JavaScript-heavy rendering is partially or completely invisible to AI engines.
Core Web Vitals – the speed and stability metrics Google uses – also affect AI crawlability. A slow site doesn't just rank lower on Google; it gets crawled less completely, which means less of your content is available to AI engines for citation.
The short version
To get your website to appear in ChatGPT recommendations, you need five things in place:
- AI crawlers allowed – GPTBot, ClaudeBot and PerplexityBot must be permitted in your robots.txt
- llms.txt file – declaring what your site is and which pages matter
- Schema markup – structured data describing your business, services and credentials
- Answer-first content – pages that directly answer the questions your customers ask
- Authority signals – third-party mentions, consistent information, named practitioners
Most sites are missing at least three of these. The free SearchScore audit identifies which ones apply to yours in 60 seconds.
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