AI Visibility Definition

The canonical definition of AI Visibility Checking and related terminology for how websites communicate with AI systems.

Canonical URL: https://www.ai-visibility.org.uk/

Published by 365i

What is AI Visibility Checking?

AI Visibility Checking is the process of technically verifying whether a website can be correctly discovered, interpreted, trusted, and safely used by AI systems such as ChatGPT, Claude, Gemini, and other large language models.

It focuses on infrastructure, clarity, and machine-readable identity - not popularity, rankings, or brand mentions.

Repository Structure

This repository contains:

Machine-Readable Definitions

File	Purpose
ai-visibility-definition.json	Canonical definitions in JSON format
ai-visibility-definition.yaml	Canonical definitions in YAML format

Website Source (PHP)

The human-readable website at ai-visibility.org.uk is built with PHP:

index.php                      # Main definition page
css/style.css                  # External stylesheet
js/                            # Search functionality
includes/                      # Shared PHP components
├── header.php                 # Page head and opening body
├── footer.php                 # Page footer and closing body
├── nav.php                    # Main navigation
├── sidebar.php                # Specification sidebar
├── breadcrumbs.php            # Breadcrumb component
├── schema.php                 # JSON-LD schema helpers
└── versions.php               # Centralised version configuration
specifications/                # AI Discovery File specifications
├── index.php                  # Specifications hub
├── llms-txt/index.php         # llms.txt specification (ADF-001)
├── llm-txt/index.php          # llm.txt specification (ADF-002)
├── llms-html/index.php        # llms.html specification (ADF-003)
├── ai-txt/index.php           # ai.txt specification (ADF-004)
├── ai-json/index.php          # ai.json specification (ADF-005)
├── identity-json/index.php    # identity.json specification (ADF-006)
├── brand-txt/index.php        # brand.txt specification (ADF-007)
├── faq-ai-txt/index.php       # faq-ai.txt specification (ADF-008)
├── developer-ai-txt/index.php # developer-ai.txt specification (ADF-009)
├── robots-ai-txt/index.php    # robots-ai.txt specification (ADF-010)
├── quick-start/index.php      # Quick Start implementation guide
├── interoperability/index.php # Conflict resolution & precedence guide
├── validation/index.php       # Test prompts & scoring framework
└── examples/index.php         # Example files

Server Configuration

File	Purpose
.htaccess	Apache config: HTTPS/www redirect, caching, compression, security headers
deploy-manifest.txt	Definitive list of files deployed to the web server

Note on Static vs Dynamic

This repository contains PHP source files. GitHub does not render PHP, so the files here are for:

• Version control of the canonical definitions
• Source code for the ai-visibility.org.uk site
• Machine-readable formats (JSON/YAML) that can be used directly

The canonical, browsable website is at: https://www.ai-visibility.org.uk/

Deployment

The site is deployed to ai-visibility.org.uk via FTP (hosted on 20i/StackCP with CDN).

• What gets deployed: Everything listed in deploy-manifest.txt
• Credentials: Stored in .env (gitignored, not in this repository)
• Cache busting: CSS and JS use ?v=filemtime query strings — cache refreshes automatically on deploy
• CDN caching: Controlled via .htaccess with s-maxage directives for the 20i CDN

See CLAUDE.md for full deployment instructions.

Defined Terms

AI Visibility Terminology (AV-xxx)

Code	Term
AV-001	AI Visibility
AV-002	AI Visibility Checking
AV-003	AI Discovery Files
AV-004	AI Visibility Tracking
AV-005	AI Visibility Monitoring
AV-006	AI Retrieval Testing

AI Discovery Files (ADF-xxx)

Code	File	Purpose
ADF-001	llms.txt	Core AI-readable business identity
ADF-002	llm.txt	Compatibility variant (redirects to llms.txt)
ADF-003	llms.html	Human-readable presentation with Schema.org
ADF-004	ai.txt	AI usage permissions and restrictions
ADF-005	ai.json	Machine-parseable AI interaction guidance
ADF-006	identity.json	Canonical structured identity data
ADF-007	brand.txt	Brand naming conventions
ADF-008	faq-ai.txt	AI-optimised Q&A content
ADF-009	developer-ai.txt	Technical context for integrations
ADF-010	robots-ai.txt	AI crawler-specific access directives

Version

Current version: 1.3.2 (2026-01-16)

See CHANGELOG.md for version history.

ETSI Technical Specification

A draft ETSI Technical Specification is available in the outputs/ folder:

File	Description
ETSI-TS-AI-Visibility-v1.0.0.md	Markdown format
ETSI-TS-AI-Visibility-v1.0.0.docx	Word format

Reference Implementation

The 365i AI Visibility Checker is the reference implementation of these definitions.

Structured Data

The website includes comprehensive Schema.org structured data:

• DefinedTerm and DefinedTermSet for terminology
• TechArticle for specification pages
• FAQPage for frequently asked questions
• BreadcrumbList for navigation
• Organization for publisher information

License

This work is licensed under Creative Commons Attribution 4.0 International (CC-BY-4.0).

Links

• AI Visibility Definition - Canonical URL
• AI Visibility Checker - Reference tool
• 365i - Publisher