Glossary
AEO and Agentic Commerce Glossary: 39 Terms
Plain definitions of the 39 terms you meet when making a store visible and usable for AI systems – from GPTBot and llms.txt to UCP, AP2 and AI share of voice. One line each, with a link to the full page.
In one sentence
Every AEO and agentic commerce term on one page, one line each.
Sections: Basics · Crawlers and access · Content for AI · Structured data · Agentic commerce · Measurement
Every term links to its own page with the full definition, examples, sources and a verification date. Start with the Magento AEO checklist if you want the order of work rather than the words.
Basics
- AEO (Answer Engine Optimization)
- Making a store readable and usable for AI assistants such as ChatGPT, Claude, Perplexity and Gemini.
- GEO (Generative Engine Optimization)
- The same work under another name: being included and cited in AI-generated answers.
- LLMO (LLM Optimization)
- A third name for it, focused on how language models ingest a catalogue.
- SEO vs GEO vs AEO
- How the three disciplines differ in practice.
- AI Commerce Visibility
- Whether AI systems discover, trust and select a store for a recommendation.
- AI Commerce Stack
- The five layers from structured data up to an AI-completed purchase.
- AEO score
- A weighted 0-100 score of 20 signals: how ready a store is for AI systems.
Crawlers and access
- GPTBot vs OAI-SearchBot
- OpenAI's training crawler and its search crawler: two jobs, two robots.txt rules.
- Google-Extended
- A robots.txt token for Gemini training and grounding. Not a crawler, and not an AI Overviews switch.
- Web Bot Auth
- Bots prove who they are by signing their HTTP requests.
- Content Signals and RSL
- Machine-readable statements of what AI may do with content after fetching it.
- AI crawlers reference
- Every AI user agent that matters for a store, with what blocking it does.
Content for AI
- llms.txt
- A short Markdown map of a site's key pages, served at the root.
- llms-full.txt
- The full text of a site in one file. A convention, not part of the llms.txt spec.
- Markdown mirror
- A clean Markdown copy of a page at the same URL with .md added (llms.txt v2).
- llms.jsonl
- One JSON object per line, one per product: the catalogue in machine form.
- AGENTS.md
- Instructions for AI agents – for coding agents in a repository, for shopping agents on a store.
Structured data
- offers.availability
- The schema.org field that says whether a product can be bought right now.
- Entity @id
- The JSON-LD identifier that links organization, products and authors into one graph.
- Return and shipping schema
- hasMerchantReturnPolicy, shippingDetails and hasShippingService, store-wide and per product.
- FAQPage after May 2026
- What FAQ markup still does now that Google shows no FAQ rich results.
Agentic commerce
- Agentic commerce protocols
- ACP, UCP, AP2 and MCP side by side: who leads each and what it does.
- ACP (Agentic Commerce Protocol)
- OpenAI and Stripe's standard, now mainly the route to ChatGPT product discovery.
- ACP product feed
- The catalogue file sent to OpenAI: nine required fields, one row per item.
- UCP (Universal Commerce Protocol)
- Google's protocol for discovery and transaction, through a profile the store publishes.
- /.well-known/ucp
- The UCP business profile: version, services, capabilities and public keys.
- UCP authority binding
- The check that a UCP schema URL is served from a host the namespace owner controls.
- AP2 (Agent Payments Protocol)
- Signed mandates that prove a person approved an agent's purchase.
- MCP for commerce
- Using the Model Context Protocol to expose catalogue and checkout as tools.
- Agentic checkout
- A purchase completed by an AI agent while the store stays the seller.
- Commerce agent
- AI that acts on catalogue, cart and order data for shoppers or for staff.
- Merchant of record
- The company that legally sells: payment, tax, refunds and the customer contract.
- Shared Payment Token
- A single-use ACP payment token limited to one merchant, one checkout and one amount.
- A2A Agent Card
- The public profile of an A2A agent at /.well-known/agent-card.json.
- MCP and agentic commerce glossary
- Implementation terms: JSON-RPC, Streamable HTTP, PKCE, RFC 8707, tool annotations.
Measurement
- AI share of voice
- How often assistants name your brand, compared with competitors, on fixed questions.
- Grounding
- Whether an AI answer uses content fetched for the question or only training data.
- GA4 AI Assistant channel
- GA4's automatic channel for AI-referred visits since May 2026, and what it misses.
- Measuring AI visibility
- Three layers: can AI read the store, does it name you, do people arrive and buy.
Questions
- What does this glossary cover?
- 39 terms for making an online store readable and usable by AI systems: crawlers, llms.txt, structured data, agentic commerce protocols and measurement. Each links to a full definition.
- Where is the MCP implementation vocabulary?
- In the separate MCP and agentic commerce glossary under /docs/mcp-glossary/, which covers JSON-RPC, transports and OAuth terms.
- How current are the definitions?
- Each definition page states when it was last checked against its sources. Protocol versions and crawler names change, so check that date.