When a brand was mentioned in an AI answer, the same question on the same engine mentioned it again the next day 57.9% of the time. That comes from 8,740 answers Zumi collected over 11 days. On ChatGPT alone, the figure was 54.7%.
An AEO checker, short for answer engine optimization checker, usually reports one run. The figure above is how often a yes from such a run held a day later. A readiness score from the same kind of tool mixes items the engines document with items no engine has asked for.
This guide sets out what each kind of check can support, using Zumi's own answers and the engines' own documentation.
Key takeaways
- In Zumi's run of 304 beauty-category questions, a brand mentioned in one answer was mentioned again in the next day's answer 57.9% of the time. ChatGPT: 54.7%. Perplexity: 58.1%. Google AI Overviews: 62.3%.
- Only 6.3% of brands that appeared for a question on an engine appeared in every answer to it. A single day's yes or no disagreed with the brand's result on most days 21.2% of the time.
- OpenAI, Anthropic, and Perplexity each name the crawler that reads sites for their AI search, and Google requires a page to be indexed in Search. None of their crawler pages says the crawlers read llms.txt.
- Google states that no new "AI text files, or markup" are needed to appear in AI Overviews or AI Mode. A readiness score that rewards them is rewarding work no engine asked for.
- A brand's standing in AI answers shows in how often it returns across repeated answers, which a single check cannot measure.
What does an AEO checker check?
Two different things share the name. A readiness check scans a website and returns a score. It looks at items such as crawler access, structured data (code that labels page content for search engines), and llms.txt, a proposed text file meant to summarize a site for AI tools.
An answer check, often sold as a ChatGPT visibility checker, asks one or more AI engines a few buyer questions. It reports whether the brand was mentioned.
Either way, the result is a snapshot of one day. The sections below measure how much that matters for each kind.
A separate search, "ChatGPT citation checker", mostly leads to academic tools that test whether references ChatGPT wrote are real. That is a different job from checking whether ChatGPT mentions a brand.
How often does a yes from a checker hold the next day?
Zumi asked 304 questions about beauty and personal care in India every day from 23 July to 2 August 2026, on ChatGPT, Perplexity, and Google AI Overviews. For every brand mentioned in an answer, the next day's answer to the same question on the same engine was checked for the same brand.
Across 39,894 such cases, the brand returned in 57.9%:
| Engine | Mentioned again the next day | Cases |
|---|---|---|
| ChatGPT | 54.7% | 17,873 |
| Perplexity | 58.1% | 9,715 |
| Google AI Overviews | 62.3% | 12,306 |
| All three | 57.9% | 39,894 |
Steady presence was rare. Of 12,359 pairings of a brand with a question on one engine, where the brand appeared at least once, 776 (6.3%) appeared in every answer across the run.
| Run detail | Value |
|---|---|
| Answers | 8,740 |
| Questions | 304, beauty and personal care, India |
| Dates | 23 July to 2 August 2026, 11 days |
| Engines with daily repeats | ChatGPT, Perplexity, Google AI Overviews |
This is one category in one market. Other categories may hold steadier or move more. Nothing in the method is specific to beauty.
What does a single check get wrong?
Both a yes and a no are unreliable. Each brand has a usual result on each question: present or absent, whichever held on most days of the run. A single day's result disagreed with that usual result 21.2% of the time.
A yes on the day of the check shows that the engine can mention the brand. A no shows that it did not, that day. Neither describes the brand's standing.
The whole brand list moves too. The guide to evaluating AI visibility tools found that only 7.3% of back-to-back answers in the same run mentioned exactly the same brands. Two checkers that each ask once can disagree on the same brand and both be accurate for the moment they ran.
Which readiness items do the engines ask for?
Each engine documents which crawler reads sites for its AI answers. OpenAI names OAI-SearchBot, and Anthropic names Claude-SearchBot. Perplexity names PerplexityBot, and Google requires a page to be indexed and able to show a snippet, the short text preview under a search result.
Google is direct about the rest: "You don't need to create new machine readable files, AI text files, or markup to appear in these features. There's also no special schema.org structured data that you need to add." None of the four crawler pages says its crawlers read llms.txt.
| Readiness item | Documented by an engine? | Weight in a score |
|---|---|---|
| Search crawler allowed in robots.txt, the file that tells crawlers what they may read | Yes, by OpenAI, Anthropic, Perplexity, and Google | Pass or fail; the first fix |
| Pages indexed and snippet-eligible in Google Search | Yes, by Google, for AI Overviews and AI Mode | Pass or fail |
| llms.txt and similar AI text files | No | None as a lever |
| Schema markup added to win AI answers | No; Google says none is needed | None as a lever |
A readiness score that blends these rows into one number hides the only items with a documented effect. The useful output of a readiness check is the pass or fail on the first two rows.
What should replace a single check?
Repetition, on a fixed set of questions. The manual AI visibility baseline sets out how to run one by hand: fixed questions, fixed engines and conditions, raw answers kept, and the same run repeated.
When the questions or engines outgrow a spreadsheet, the tool evaluation guide covers what to ask a vendor first. The key question is how often each question is asked, and how many answers stand behind each figure.
Zumi, an AI Search Intelligence Platform, refreshes each tracked question daily and reports how often a brand is mentioned across those answers, engine by engine. Book a demo to see a brand's own questions tracked over time.
Sources
- Zumi, India beauty and personal care answer run: 8,740 answers, 304 questions, ChatGPT, Perplexity, and Google AI Overviews, 23 July to 2 August 2026.
- Google Search Central, "AI features and your website", last updated December 2025.
- OpenAI, "Overview of OpenAI crawlers", checked 12 October 2026.
- Anthropic, "Does Anthropic crawl data from the web, and how can site owners block the crawler?", checked 12 October 2026.
- Perplexity, "Perplexity crawlers", checked 12 October 2026.