GEO Agency: What Generative Engine Optimisation Buys You

A GEO agency optimises your brand specifically for generative answer engines, ChatGPT, Perplexity, Gemini and Claude, rather than for Google’s search results page. The work covers how those engines retrieve and cite content, not classic keyword ranking, and it moves at different speeds: Perplexity can shift within weeks, ChatGPT typically takes months.

Quick links

• What is GEO, and how does it differ from AEO and SEO?
• What does a GEO agency actually do?
• How long does GEO take to show results?
• What signals mean it’s time to hire a GEO agency?
• How do you choose the right GEO agency?
• FAQ

What is GEO, and how does it differ from AEO and SEO?

GEO is the practice of optimising specifically for the retrieval and citation mechanics behind generative answer engines, rather than for a search results page. It sits inside the broader work we call AEO, which covers every surface an AI might answer from, including Google’s own AI Overviews.

The term has a genuine research pedigree, which is more than most search jargon can claim. Generative Engine Optimization was coined in a 2023 paper by researchers from Princeton, Georgia Tech, the Allen Institute for AI and IIT Delhi, who built a framework for testing which content changes move visibility inside a generated answer. Their headline finding: adding citations, statistics and clearer structure at the passage level, rather than the page level, lifted visibility in generative responses by up to 40% (arXiv:2311.09735).

That distinction between page-level and passage-level matters more than the acronym soup around it. Classic SEO ranks whole pages. AEO, as we use the term day to day, is the umbrella: making a brand the one an AI names across any answer surface. GEO is the sharper, more technical end of that, the specific mechanics of how a generative model selects, weighs and quotes the passages it pulls an answer from. We go deeper on where AEO and SEO diverge in our AEO explainer; this piece is about the GEO-specific slice, and what an agency selling it under that name should be doing for the fee. It is also, in practical terms, what our own GEO service covers, run as a fixed monthly scope rather than a term of art.

In practice, most agencies use “GEO agency” and “AEO agency” to mean roughly the same commercial work. Worth knowing, so you are not paying twice for it under two different names.

What does a GEO agency actually do?

A GEO agency restructures content for passage-level extraction, fixes the access layer so generative crawlers can reach it, and builds the outside citations that make a model confident enough to name you. Skip any one of the three and the other two do less than they should.

Passage-level content work. The Princeton paper’s most practical finding is that generative engines do not reward whole pages so much as they extract and quote specific passages, and adding statistics, direct citations and clear structure to those passages measurably increases the chance a model quotes yours. That means rewriting the paragraphs most likely to answer a buyer’s actual question, not just publishing more content.

Crawler and retrieval access. OpenAI runs three separate crawlers for different jobs: GPTBot for training, OAI-SearchBot for what ChatGPT search cites, and ChatGPT-User for requests made live inside a chat. Perplexity runs its own retrieval pipeline, searching the live web on most queries rather than leaning solely on stored training data, according to Perplexity’s own account of how it works. If any of those cannot reach your key pages, whatever you write is invisible to that engine specifically, and a decent GEO agency checks this before touching a single word of copy.

Entity and citation building. The same off-site work AEO does more broadly, consistent business details, third-party mentions, reviews, feeds directly into whether a generative model trusts what your own site says about you. This is the slow, unglamorous part, and usually the part a cut-price package skips entirely.

Ongoing prompt tracking sits on top of all three: testing the buyer questions that matter across engines every month, rather than a single audit filed away and forgotten.

How long does GEO take to show results?

Perplexity can shift within weeks because it searches the live web on most queries. ChatGPT usually takes months, because a meaningful share of what it knows still comes from a training snapshot rather than a live search.

Honest answer, in full: it depends entirely on which engine you mean, and a GEO agency that quotes one blanket timeline for “AI search” generally is not being straight with you.

Perplexity moves fastest. Most queries trigger a fresh web search, and the model writes its answer from whatever it finds at that moment rather than from a fixed training set, per Perplexity’s own explanation of how it works, linked above. Fix your crawler access and your content, and you can see a shift inside a few weeks.

ChatGPT moves slower. A chunk of what ChatGPT knows still comes from the model’s training data, which OpenAI freezes at a cutoff date well before release, and updating that requires a new training run rather than a page revisit. OpenAI’s own explanation of how the models are developed confirms the model has no access to real-time information unless search is switched on for that session. When search is on, its OAI-SearchBot index behaves more like Perplexity’s. A lot of everyday ChatGPT use still draws on the frozen model underneath it, so expect months, not weeks, for a durable shift.

Google’s AI Overviews sit in between. They draw on the same index as ordinary Google results, so a change that helps you rank tends to help you get cited there on a broadly similar timeline to normal SEO movement.

Any agency promising a fast win everywhere is quietly averaging across three very different systems. Ask which engine a projected timeline actually refers to before you sign anything.

What signals mean it’s time to hire a GEO agency?

The clearest signal is that generative engines are already shaping your buyers’ shortlist, whether or not you have checked. If you have not tested it yet, that is the first move, and it costs nothing.

Gartner predicted in 2024 that traditional search engine volume would fall 25% by 2026, as buyers shift queries to AI chatbots and other assistants instead of typing them into Google, according to the firm’s own press release. Whether the final number lands exactly on 25%, the direction is not in dispute. A meaningful slice of research that used to happen on Google now happens inside a chat window instead.

A few checks worth running before you brief anyone, none of which take long:

• Ask ChatGPT and Perplexity a buyer-style question about your category, and see whether you are named and whether the answer gets your details right.
• Check whether a direct competitor gets named instead, in the same answer, for the same question.
• Look at whether your key pages actually reach those engines: view the page source and see if the content that matters is in the raw HTML, or only appears once JavaScript has run.
• Ask whether anyone on your team currently owns the question “what does AI say about us”, or whether it is nobody’s job.

None of those need an agency to check. They just need doing, and most businesses have not done them yet.

How do you choose the right GEO agency?

Ask what they measure and how they prove it, not what they promise. A programme with no visible method for testing prompts across engines is a report, not a service.

The discipline is young enough that plenty of agencies are still learning it in public, on client budgets. A short list of questions filters out most of the noise fast:

• What exactly do they track? Prompt-level testing by engine, not a single composite “AI visibility score” nobody can explain the maths behind.
• Do they touch the technical layer, or only the writing? Content sitting behind a crawler block or a JavaScript-only render is wasted effort, so ask to see the technical checks, not just the copy.
• Can they show a real result? A site they rebuilt or rewrote, with a before-and-after they will walk you through, beats a deck of intentions. When we rebuilt Hoc Paid Media’s site around structure, schema and a genuinely fast stack, the business had its first inbound lead within 24 hours of launch, detailed in the full case study.
• How do they price it? A fixed monthly scope is easier to hold to account than an open hourly arrangement, because you know upfront what a month of work should include.
• Do they understand where GEO stops and ordinary SEO starts? If the pitch is that GEO replaces SEO entirely, that is a red flag, not a selling point.

Get straight answers to those and you will know within one call whether you are talking to someone who ships this work, or someone who has read the same explainer posts everyone else has.