AI Engine Optimisation

GEO Signals: Reference Guide

AI engines (ChatGPT, Perplexity, Claude, Google AI Overviews) look for specific signals when deciding which page to cite. This guide covers the 23 signals TrustData measures in its Page Structure Audit.

Core Signals

Structural and content signals that apply to every page type.

Core

AI Bot Access via robots.txt

Allowing AI crawlers (GPTBot, ClaudeBot, PerplexityBot) to index and cite your content.

Core

Author Attribution

A visible author byline with name, credentials, and schema markup identifying who wrote the content.

Core

Authority References

Outbound links to high-authority domains (.gov, .edu, Wikipedia, major publishers) that anchor your claims.

Core

Case Studies

Real-world examples showing measurable results that AI engines use to answer "does X work?" queries.

Core

Clear Takeaway / Key Summary

An explicit summary section that surfaces the page's conclusion for AI extraction.

Core

Comparison Content

A section comparing your product to alternatives, addressing "what is the best X" queries directly.

Core

Content Freshness

A visible publication or last-modified date that lets AI engines assess whether the information is current.

Core

Specific Data & Statistics

Concrete numbers, percentages, and measurable claims that give AI engines verifiable facts to cite.

Core

External References

Outbound links to credible external sources that support your claims.

Core

FAQ Blocks for AI Citability

A dedicated question-and-answer section that AI engines can extract and surface directly.

Core

Heading Hierarchy

Using H1 → H2 → H3 to structure content into scannable, topic-segmented sections.

Core

Images with Descriptive Alt Text

Relevant images with alt text that reinforces the page's topic and entities.

Core

Intro Summary

A concise opening paragraph (under 80 words) that states what the page is about and who it's for.

Core

List Formatting

Bullet or numbered lists that present information in a structure AI engines can extract cleanly.

Core

llms.txt

A plain-text file at /llms.txt that tells AI crawlers what your site is about and what they may use.

Core

On-Page Reviews & Ratings

Customer reviews and aggregate ratings directly embedded on the product page.

Core

Pricing Visibility

Clear, machine-readable pricing on the page that AI shopping assistants can extract.

Core

Product Schema

schema.org/Product markup that makes product details machine-readable for AI shopping assistants.

Core

Schema Markup for AI Engines

JSON-LD structured data that tells AI crawlers what type of content a page contains.

Core

Social Proof

Quantified indicators of adoption — customer count, logos, industry recognition — that establish credibility.

Core

Structured Comparison Tables

HTML tables that present comparative or structured data AI engines can extract as facts.

Core

Testimonials

Named client quotes with attribution that provide social proof and human credibility signals.

Core

Use Cases

Explicit statements of who the product is for and what problems it solves.

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