AI SEO: What It Is and What Actually Works

AI SEO is the work of making your website easy for AI search tools to find, understand and cite, alongside the use of AI tools to do SEO tasks. The first half is often called generative engine optimisation, or SEO for AI. The second is AI for SEO.

This guide sets out what Google, OpenAI, Perplexity and Anthropic have published, what one piece of research found, and what we saw when we tested our own site. We promise no citations, because nobody can.

What is AI SEO?

“AI SEO” is used for two different jobs, and mixing them up causes confusion.

AI in SEO, or AI for SEO, means using AI tools to help with the work: drafting briefs, summarising data, checking pages. The tool is a helper, and you still own the result.

SEO for AI, or AI search optimisation, means shaping your site so that AI search products can find it and use it in answers. That covers Google’s AI Overviews and AI Mode, ChatGPT search, Perplexity and Claude. People also call this generative engine optimisation. When people search “seo ai”, they usually mean one of these two, and it helps to know which before you read advice.

The rest of this guide is mostly about the second job, because that is where most of the confusion and most of the sales claims sit. If you want help with it, our AI SEO agency page explains what we do.

What Google says about AI Overviews and AI Mode

Google’s AI features documentation, updated 10 December 2025, is blunt. It says there are no extra requirements or special optimisations needed to appear in AI Overviews or AI Mode. It also says no special schema.org structured data is needed.

Three practical points follow from that page:

• Snippet controls still apply. The controls nosnippet, data-nosnippet, max-snippet and noindex apply to these AI features, so if you use them you are also limiting what AI features can show from your pages.
• There is no separate AI report. Google says traffic from AI features is counted in the Search Console Performance report under “Web”. You can’t pull out an “AI Overviews” line.
• Normal SEO is where we start. With no AI-specific requirements published, our view is that sound ordinary SEO is the sensible place to begin. Our SEO Cornwall page covers those basics for local businesses.

Do you need structured data or an llms.txt file?

Not according to Google. Its AI optimisation guide, updated 10 July 2026, says structured data isn’t required for generative AI search, and that you don’t need special AI text files, markup or Markdown.

That matters because llms.txt gets sold as a quick win. It is a proposal by Jeremy Howard from September 2024 for a markdown file that helps agents use a site. No provider has officially said its search uses it. Adding one is cheap and harmless, but you shouldn’t pay for it as if it were a ranking factor.

The AI crawlers and your robots.txt

This is the one place where a technical setting really can change whether you appear. The AI companies publish separate bots for different jobs, and you can treat them differently.

• OpenAI (bot documentation): OAI-SearchBot surfaces sites in ChatGPT search, and a site that opts out won’t be shown in ChatGPT search answers. GPTBot is for training. ChatGPT-User acts on user requests, and robots.txt may not apply to it. Each bot is controlled separately in robots.txt.
• Perplexity (bot documentation): PerplexityBot surfaces and links sites in results, isn’t used for training and obeys robots.txt. Perplexity-User generally ignores robots.txt.
• Anthropic (crawler help article): there are three bots. ClaudeBot is for training, Claude-User handles user requests and Claude-SearchBot relates to search quality. All can be controlled via robots.txt.

The practical lesson is that “block AI” is not one decision. Many site owners will want to stay out of training while staying visible in search. If you block a search bot, the documentation above says you shouldn’t expect to be shown by that product. Open your robots.txt, read what it says about each bot name, and make a deliberate choice for each.

What the research says about generative engine optimisation

The best-known study is Aggarwal et al. (arXiv 2311.09735). The authors built GEO-bench, a set of 10,000 queries, and tested methods on a GPT-3.5-turbo-based engine and on Perplexity. They report that adding citations, quotations and statistics improved visibility by over 40%, while keyword stuffing gave little or no improvement.

Treat that with care. It tested engines from 2023 and 2024, inside the authors’ own setup. It doesn’t tell you how today’s ChatGPT, Gemini or Claude behave on your queries. What it does support is a habit we’d follow anyway: say something specific, show where it comes from, and don’t repeat keywords for the sake of it.

What we saw when we tested ourselves

On 2 October 2026 we ran 10 UK buyer prompts, such as “best digital marketing agencies in Cornwall”, across ChatGPT, Claude, Perplexity and Gemini. Outcome was named in 4 of 40 answers: Perplexity 2, ChatGPT 1, Claude 1 and Gemini 0.

One result stood out. In a single Gemini answer, our restaurant marketing article was cited as a source 16 times, yet Gemini did not name us as an agency to hire. Being a cited source and being recommended are different things. A page can be used as reading material while the answer still sends the buyer elsewhere.

This is a small snapshot, not a study. Ten prompts on one day, from one business, can’t tell you how AI engines behave in general. We share it because it shows the shape of the problem honestly, and it is why we don’t promise citations to anyone.

AI SEO tools: what to check

We haven’t benchmarked any AI SEO tools, so we won’t name or rank any. What we can do is describe the categories and the questions to ask.

Writing and briefing tools help draft or outline content. Check whether they show their sources, and whether a person with real knowledge of your business reviews what they produce. Content with no sourced facts is the opposite of what the research above supports.

AI visibility trackers report whether your brand appears in AI answers. Check which prompts they run, how often, on which engines, and whether you can repeat a result yourself. Answers vary, so a single reading proves little. Our own test above is a good reminder of that.

AI features inside existing SEO suites add summaries or suggestions to tools you may already use. Check whether they change your site or only report on it, and what they cost to run repeatedly.

Whatever you choose, remember Google’s statement that AI feature traffic sits inside the normal “Web” report in Search Console. A tool that claims a separate, precise AI traffic number is working from its own method, not from Google’s data.

Where AI helps SEO work, and where it doesn’t

Used as a helper, AI is useful for the dull parts of SEO: tidying a spreadsheet of page titles, summarising a long export, or turning rough notes into a first draft you then rewrite. Those are low-risk jobs because you can see the output and correct it.

It is a poor substitute for knowing your own business. A model has no idea which of your services earns you money, which towns you actually cover, or what a customer told you last week. Those details are what make a page worth citing, and only you can supply them. If AI wrote the page and nobody added a real fact, a real example or a real source, you have added to the pile of generic pages, not stood out from it.

What to do instead

You don’t need a new discipline. You need the existing one done well, with a few specific checks:

1. Open your robots.txt and decide, bot by bot, which search crawlers you want to allow.
2. Keep key pages indexable and check you haven’t set snippet limits you didn’t mean to.
3. Answer the question first, then back it up with facts you can source. That matches what the GEO research found helped, within its limits.
4. Make it clear who you are and where you work. For local businesses, a complete Google Business Profile and consistent details help every search product.
5. Test it yourself. Run a few real buyer prompts on the main engines, note what is named and what is cited, and repeat now and then. Treat it as a snapshot.

For a plain-English answer on the local side, see our FAQ on getting cited by ChatGPT as a local business. If you’re in Cornwall, our AI SEO Cornwall page explains how we fold this into our SEO work. If you’d rather have someone do the checking for you, that is what our AI SEO agency service is for.