A complete reference
What is AEO?
Answer Engine Optimization makes a website easier for AI retrieval systems to access and understand, then measures whether it appears as a cited source. No implementation can guarantee selection.
- 13technical checks in the current Meridian15 AEO audit
- 66possible audit points before penalties
- 8points assigned to retrieval-agent access
- 2points assigned to optional llms.txt discovery
The 30-second answer
AEO in one paragraph.
AEO (Answer Engine Optimization) makes public content easier for retrieval systems to access and understand, then measures whether that content appears as a cited source. SEO measures rankings and organic traffic. AEO adds retrieval readiness and source monitoring. A sound baseline has crawlable content, accurate structured data where appropriate, accountable authorship, retrieval access, and useful source material. llms.txt is optional, and FAQPage belongs only where matching Q&A is visible. Neither guarantees citations.
If your buyers use ChatGPT, Perplexity, or Google AI Overviews, AEO gives you a way to improve observable source readiness and measure whether your brand appears. The product still decides which sources to select.
01The shift
Search behaviour now spans more products than classic results alone.
For two decades, the way to be found online was simple: rank on Google, get clicks, convert traffic. Search engines returned a list of ten blue links, the user picked one, the site they picked got the visit. The whole industry of SEO was built around moving up that list.
Search now includes classic results, AI summaries, assistants, and research products. Usage and source presentation vary by category, query, location, product, and date. There is no single adoption percentage that describes every commercial search or buyer journey.
When a source citation appears, it creates another discovery path. When it does not, that result is one observation, not proof that a brand is invisible. AEO adds retrieval access, explicit source material, and repeat source monitoring to an SEO foundation. Products may combine indexes, retrieval systems, and language models in different ways, so measure rankings, traffic, citations, and referrals separately.
02Defined
Three layers to audit before citation monitoring.
A useful way to plan AEO is in three practical layers. They organize observable work, but they are not universal source-selection filters and none guarantees a citation.
Layer 01
Machine readability
Can retrieval agents access crawlable page content and can machines identify the page accurately? Blocking access can prevent direct retrieval, but structured data alone is not a selection guarantee.
- Valid JSON-LD schema
- Optional llms.txt discovery file
- Clean sitemap
- Retrieval access checked separately from training policy
- Semantic HTML
JSON-LD: a JavaScript Object Notation format for embedding structured data inside a web page. Search engines and AI parsers read it to understand what the page is about.
Layer 02
Content accountability
Once a page is crawlable, make its ownership, claims, dates, and evidence explicit. These qualities help readers and retrieval systems interpret the source without guaranteeing selection.
- Named author
- FAQPage schema
- Quotable claims
- Publication dates
- Entity coverage
FAQPage: a schema.org type for visible question-and-answer pairs. It must match the page and does not guarantee ranking or citation.
Layer 03
Authority
Third-party evidence can support factual claims and entity consistency. Its effect varies by query and product, so measure outcomes rather than assuming a compounding citation advantage.
- Quality backlinks
- Brand mentions
- Domain age
- Third-party reviews
- Industry coverage
03Citation criteria
Technical factors you can verify before monitoring citations.
Source-selection systems are proprietary and change over time. The factors below are observable content and technical checks, not universal filters or weights.
- 01
Answer the actual buyer question.
Some systems expand or decompose a query during retrieval. Pages should answer the buyer question with clear, factual sections, but no specific content shape guarantees source selection.
- 02
Make content crawlable and explicit.
Crawlable HTML and accurate structured data help machines interpret a page. They do not establish a universal order between parseability and authority, and they do not guarantee that a cleaner page will be cited.
- 03
Keep dates, claims, and evidence accurate.
Use factual publication and modification dates. Time-sensitive queries may need current evidence, but adding a recent date or Article schema does not guarantee ranking or citation.
- 04
FAQ schema must match visible answers.
FAQPage schema describes visible question and answer content in a machine-readable format. It is not a ranking factor, and the Meridian15 audit treats exact visible-to-schema parity as an optional 2-point check out of 66.
- 05
Use accountable claims and consistent entity information.
Keep organization details, author identity, and third-party claims factual and consistent. Avoid keyword stuffing. No universal rule says entity coverage outweighs every other factor in every product.
Want to know how an AI engine reads your site right now? Run our free AEO audit and review 13 observable technical checks totalling 66 possible points. The score is not a citation prediction.
04AEO vs SEO
The two are not in conflict, but they are not the same.
The most common mistake we see is treating AEO and SEO as alternatives. They are not. They share infrastructure but optimize for different outcomes. We cover the full breakdown in a separate post; here is the short version.
| Compared | SEOOptimizes for being clicked. | AEOOptimizes for being cited. |
|---|---|---|
| Output | Ranked list of blue links | Brand named inside an AI-generated answer |
| Metric | Clicks, sessions, conversions from organic | Citation share across engines, answer placements |
| Optimizes for | Keyword targeting, page speed, internal linking, backlinks | Crawlable content, accurate schema, accountable authors, retrieval access, source monitoring |
| User behaviour | Scans the SERP, picks a result, lands on the site | Reads the answer and may follow a source link |
| Time horizon | Varies by query and competition | No fixed citation timeline |
AEO and SEO share a foundation of useful content, crawlable pages, accurate business information, and credible sources. Google applies the same SEO practices to its AI features. Match each page to a real buyer question and measure search visits, AI citations, and enquiries separately.
If buyer research shows that classic search drives discovery, keep SEO central. If repeated query sampling shows that AI answers affect the category, add source monitoring and answer-focused content. Do not assume AEO weight increases every quarter for every brand.
05Engine quirks
Source presentation differs by product and mode.
ChatGPT, Perplexity, Google AI Overviews, and Claude expose different retrieval agents, training controls, and source interfaces. Treat public access controls separately and measure source selection instead of inventing a universal refresh order or weighting model.
| Engine | Retrieval access | Citation style | Training control | What access means |
|---|---|---|---|---|
| Perplexity | PerplexityBot | Source presentation varies by product and mode | No paired training-control claim in this audit | Retrieval access does not guarantee selection |
| Google AI Overviews | Googlebot for Search indexing | Source presentation varies by query and product | Google-Extended is a separate training control | Google does not use llms.txt |
| ChatGPT | OAI-SearchBot and ChatGPT-User | Source presentation varies by product and mode | GPTBot is a separate training control | Retrieval access does not guarantee selection |
| Claude | Claude-SearchBot and Claude-User | Source presentation varies by product and mode | ClaudeBot is a separate training control | Retrieval access does not guarantee selection |
The practical takeaway: keep content crawlable, structured data accurate, and retrieval access explicit. llms.txt is optional, Google does not use it, and training crawler policy is separate. Measure each product without claiming a fixed weighting or refresh order.
06How we track it
How we track citations.
We do not report a generic citation curve. We fix a set of questions your buyers ask, check each one in ChatGPT, Perplexity and Google AI Overviews, and write down what every answer cites. Then we ask the same questions again and report what changed, and what did not.
| Field | What we write down |
|---|---|
| The question | The exact words a buyer types, the same every time. |
| The product | ChatGPT, Perplexity or Google AI Overviews, and the mode it answered in. |
| The date | The day the question was asked. |
| The sources | Every source the answer cites, in its order. |
| You | Whether your site is cited, and where. |
- Pattern 01
Set the baseline first.
Record the exact query, product, mode, date, cited sources, and answer before implementation. A baseline makes later changes measurable.
- Pattern 02
Keep the query set stable.
Compare like with like. A changing prompt set cannot prove citation growth, and a recurring citation does not establish a permanent source preference.
- Pattern 03
Report uncertainty.
Answers vary across products and over time. Report observed citations without claiming a fixed engine order, training cycle, or guaranteed catch-up.
Curious which engine is actually citing your site? The audit checks 13 observable technical signals. It does not expose proprietary source-selection systems or predict citations.
07What to do
Six baseline checks worth reviewing.
Review these six baseline items against the page and business. They are practical checks, not universal citation levers, and implementation time depends on the site.
- 01
Publish an optional llms.txt file
A curated Markdown discovery file for compatible tools. Support is incomplete, Google does not use it, and it does not guarantee citations. See the full guide.
- 02
Check retrieval access in robots.txt
Check that robots.txt does not block OAI-SearchBot, ChatGPT-User, Claude-SearchBot, Claude-User, or PerplexityBot. Decide training crawler access separately.
- 03
Add accurate Organization JSON-LD sitewide
Accurate structured data makes the brand name, URL, logo, and factual sameAs links explicit. Keep those values consistent with the visible site.
- 04
Add FAQPage schema where you have Q and A content
The schema must match the questions and answers visible on the page, word for word.
- 05
Name the author on every editorial page
Name an accountable author on editorial pages. Authorship is an 8-of-66 audit check, not a citation guarantee. Person schema with bio and credentials is the stronger version when the author is real.
- 06
Audit and iterate
Once the baseline is shipped, measure a stable query set and record what changes. Iteration does not guarantee reliable citation.
Try it now
See where your site stands.
Type a URL. We will fetch the page, run the same 13 technical checks our audit tool runs, and show you a real score in seconds. No email required.
08Mistakes to avoid
What not to do, because doing it makes things worse.
Bad implementation can make content inaccurate, inconsistent, or inaccessible. These are common technical and editorial mistakes, not a universal engine penalty list.
- Mistake 01
Faking FAQ schema with no visible Q&A.
FAQPage JSON-LD must represent matching visible questions and answers. The Meridian15 audit penalizes schema-only FAQ markup. FAQPage is not a ranking factor or citation guarantee.
- Mistake 02
Blocking AI crawlers in robots.txt.
Separate retrieval access from training policy. Check OAI-SearchBot, ChatGPT-User, Claude-SearchBot, Claude-User, and PerplexityBot for retrieval. GPTBot, ClaudeBot, and Google-Extended are separate training controls.
- Mistake 03
Walls of marketing prose with no quotable claims.
“We are a leading provider of innovative solutions” gives readers little evidence. Specific, verifiable details give people and retrieval systems clearer source material.
- Mistake 04
Hiding answers inside accordions only.
Accordions are fine for design, but keep answer text crawlable in the delivered HTML. JavaScript support varies, so do not make essential content depend on an interaction.
- Mistake 05
Stuffing keyword density.
Repeating a keyword does not create useful evidence. Write factual coverage for people, keep language natural, and evaluate search performance separately.
- Mistake 06
Skipping author attribution because “we are a brand.”
Use a factual named author or accountable organization where appropriate. Authorship is worth 8 of 66 audit points, but a meta author tag alone is not the single biggest E-E-A-T signal and does not guarantee citation.
09 · FAQ
Frequently asked.
What does AEO stand for?
AEO stands for Answer Engine Optimization. It makes website content easier for AI retrieval systems to access and understand, then measures whether the site appears as a cited source. It does not guarantee selection.
Is AEO different from SEO?
Yes. SEO measures rankings and organic traffic from search results. AEO adds retrieval readiness and monitors whether a brand appears as a source in AI-generated answers, which may or may not drive a click. They share infrastructure, but the outcomes are measured separately.
Does AEO replace SEO?
No. The two can run in parallel because they share work such as crawlability, useful content, structured data, and accountable authorship. Shared inputs can support both programs, but rankings, traffic, citations, and referrals still need separate measurement.
How do AI engines decide who to cite?
AI products use changing retrieval and source-selection systems. Crawlability, accurate structured data, accountable authorship, factual content, and retrieval access are observable inputs worth checking. Their exact weights are proprietary, and no single markup file or schema type guarantees a citation.
What is llms.txt?
llms.txt is an optional Markdown discovery file at the root of a site. Compatible tools may use it to find selected public pages, but support is incomplete, Google does not use it, and it does not guarantee citations.
What is FAQPage schema and why does it matter?
FAQPage is a JSON-LD schema type for visible question and answer pairs. The schema must match the visible text exactly. It can clarify page structure, but it is not a ranking factor and does not guarantee that an answer will be quoted.
How long does AEO take to work?
No fixed timeline. Citation timing varies by product, query, access, relevance, and source selection. Establish a baseline and monitor a stable query set. Do not promise an engine order, a 60-to-90-day result, or six-month share of voice.
Can I do AEO without an agency?
Yes for the foundational layer. A competent developer can make content crawlable, add accurate Organization and Article schema where appropriate, name authors, maintain the sitemap, and check retrieval access in robots.txt. llms.txt is optional, and training crawler policy is a separate decision.
Keep reading
Three deeper dives, one click away.
- Referencellms.txt Explained: What It Does, Who Uses It, and What It Does Not DoWhat llms.txt does, which tools may use it, and why the optional file does not guarantee citations.
- StrategyAEO vs SEO: What’s Actually Different, and What to Do About ItAEO and SEO sound similar but optimize for different outcomes. What changed, what overlaps, and what to do now.
- LocalAEO for Calgary Businesses: Why Local Brands Need to Be Cited by AI SearchAI search is reshaping how Calgary buyers find services. What AEO means for local businesses, and how to start.
Measure source visibility
Audit your site, then build the plan.
See where you stand in seconds. Then either ship the baseline yourself, or talk to us about doing it for you. If budget is the open question, here is what AEO costs, and here is what an AEO service actually includes.