---
title: "Resources: GEO Guides and the AI Search Glossary | Underneath"
description: "Guides on generative engine optimization agencies: what they do, how to choose one, whether one is worth it, and GEO vs SEO, plus the AI search glossary."
canonical: "https://underneath.agency/resources"
published: 2026-09-26
updated: 2026-09-27
publisher: "Underneath (https://underneath.agency/agent)"
entity: "https://underneath.agency/.well-known/entity.json"
---
Resources

# Field notes on how AI assistants *find and choose.*

Guides to generative engine optimization, written from our own measurements of what the AI engines cite. Our figures come from repeated runs, and you can ask us for the data behind any of them.

Featured guide

## [What does a GEO agency do?](https://underneath.agency/resources/what-does-a-geo-agency-do)

A GEO agency gets a brand cited, mentioned and recommended in AI answers. The nine things it does, what it costs in 2026, and how the AI engines themselves describe the job, measured across 22 runs.

Guide · AI search

Key takeaways

1. A GEO agency works on the pages, the structured data, the brand’s entity and the third-party sources the engines cite.
2. Published 2026 price guides put agency retainers between about $1,500 and $50,000 a month; the cheapest useful engagement is a repeated audit.
3. On Google’s AI surfaces, a top-three ranking roughly doubles a page’s chance of a citation compared with positions 7 to 10; on Perplexity and ChatGPT, ranking counts for much less.

Guides

## Four guides to *hiring a GEO agency*

- Guide · AI search

  ### [How to choose a GEO agency](https://underneath.agency/resources/how-to-choose-a-geo-agency)

  Eight criteria, a scorecard, the red flags, and the questions to ask before you sign, benchmarked against how the AI engines answer the same question.

  Underneath team
- Guide · AI search

  ### [Is a GEO agency worth it?](https://underneath.agency/resources/is-a-geo-agency-worth-it)

  When hiring one pays back, when it does not, what it costs, and the three numbers that decide it.

  Underneath team
- Guide · AI search

  ### [GEO agency vs SEO agency](https://underneath.agency/resources/geo-agency-vs-seo-agency)

  What each does, where they overlap, where measurement says they differ, and whether you need one, the other or both.

  Underneath team
- Guide · AI search

  ### [What does a GEO agency do?](https://underneath.agency/resources/what-does-a-geo-agency-do)

  The nine things a generative engine optimization agency does, what it costs, and how the engines describe the job.

  Underneath team

Reference

## The AI search *glossary.*

26 terms, from canonical URLs to query fan-out, defined in a sentence or two each.

[Open the glossary](https://underneath.agency/resources/glossary)

- AEO (Answer Engine Optimization)
- AI Mode
- AI Overviews
- AI share of voice
- AI visibility
- Answer accuracy
- Buyer prompt set
- Canonical URL
- Citation rate
- Crawl budget
- Entity
- Featured snippet
- GEO (Generative Engine Optimization)
- Grounding
- Hallucination
- hreflang
- Knowledge graph
- llms.txt
- LLMO (Large Language Model Optimization)
- Local citation
- People Also Ask
- Query fan-out
- RAG (Retrieval-Augmented Generation)
- Schema markup
- SEO (Search Engine Optimization)
- Zero-click search

Free strategy call

## Some questions are easier to answer about your own business.

Bring the one that matters most. On a free 30-minute call we’ll take a first look at it and send you a short written read afterward.

[Ask about my business](https://underneath.agency/contact)[How we work](https://underneath.agency/approach)

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