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How does AI search work? Complete process analysis from retrieval, embedding to answer generation

How does AI search work? This article breaks down the complete process of query understanding, vector embedding, and answer generation from RAG retrieval, explains why being cited by AI depends on paragraph quality rather than traditional ranking, and gives executable GEO content optimization directions.

Tenten GEO TeamPublished 2026-07-125 min read
An abstract cover image that uses cinematic light and shadow as a metaphor for the complete process of AI search from retrieval to answer generation.

AI search won’t read the entire web before answering you. It first uses vector retrieval to grab a dozen of the most relevant paragraphs from the index, and then throws these paragraphs to the language model, allowing the model to generate answers based only on these fragments. This represents a counter-intuitive thing: whether you can be cited by AI depends on whether a certain paragraph can be individually extracted and read, rather than where your web page ranks in the traditional ranking.

An AI search took four steps behind the scenes

From the time you press send to the time the answer appears, there are roughly four stages in between: query understanding, retrieval, rearrangement, and generation. A batch of content will be deleted at each stage. Whether you can survive to the end and be included in the answer is the result of passing all the levels. Most people only focus on what the answer looks like in the last step, but ignore the first three steps that determine whether you are on the candidate list.

  1. Query understanding and rewriting: The model will disassemble, complete, and even rewrite your colloquial questions into multiple subqueries to deal with vague or ambiguous questions.
  2. Retrieval: The system converts the query into a vector and retrieves dozens of text passages with the closest semantic meaning from the index. This step determines the scope of the candidate pool.
  3. Rerank: Use a more sophisticated model to rescore candidate paragraphs and push the paragraphs that are most likely to answer the question to the front.
  4. Generation: The language model only reads the final winning paragraphs, synthesizes them into a paragraph, and marks the source in an interface that supports citations.

Embedding: Turn "meaning" into a set of coordinates

The core of retrieval is embedding. The system will convert each piece of text into a string of numbers, that is, a vector, and put it into a high-dimensional space. The coordinates of content with similar meanings are close together; "unsubscribe plan" and "unsubscribe" have different literal meanings, but their vectors almost overlap. The user's question is also converted into a vector, so the search becomes a geometry problem: find the points closest to the problem in space.

This explains why keyword stuffing has limited effectiveness in AI search. The model compares semantic distance, not whether the strings completely match. What really helps is to explain a topic completely, make the relationship between concepts clear, and let the text fall into a clean and clear position in the semantic space.

RAG: The model answered "what it found," not what it remembered

Nowadays, mainstream AI searches are almost all based on RAG (Retrieval Augmentation Generation). The parameter memory of the model itself will be outdated and fabricated, so the system chooses to retrieve a batch of documents on the fly before answering, insert them into context, and require the model to answer based on this data. This is why Perplexity and AI Overviews include source links - the answers originally grew out of those retrieved documents.

AI search four-step flow chart: query understanding, retrieval, rearrangement, generation
An AI search will go through four stages: query understanding, retrieval, rearrangement, and generation, with each step screening candidate content.

AI Overviews, ChatGPT, and Perplexity are actually different

It’s also RAG, but the implementation is much different. Google AI Overviews is tied to the existing search index. The candidate sources are generally those web pages that are already ranked, and then Gemini summarizes and selects them. Perplexity prefers real-time search and emphasis ranking, with wider sources and more real-time. ChatGPT depends on the situation: when the search is turned on, it searches, and when it is not turned on, it relies on training memory to answer. The latter can easily become outdated or miss you. Only by understanding these differences can you know where to work.

After knowing the process, how to write the content?

Looking at the above four steps in reverse, the optimization direction will be clear. You need to be retrieved and selected for generation at the same time. The former relies on complete semantics and technical crawlability, while the latter relies on self-sufficiency of paragraphs, clear answers, and credible sources. These two things belong to different stages, and the answer cannot be obtained without either one.

  • Each paragraph can be read on its own, independent of context - because when extracted, it is often an isolated paragraph.
  • Directly align the questions and answers: give the conclusion first, then the reasons, so that the model does not have to guess what you want to express.
  • Replace adjectives with specific numbers, definitions, and steps. Verifiable content is easier to trust and quote.
  • Maintain semantic focus, explain a topic clearly on one page, and don’t let vectors fall into vague areas.
  • Ensure that the technical aspects can be read by AI crawlers, and robots, structured data, and rendering methods must be taken into consideration.

Every step of AI search is filtering, and your content must live all the way to the moment it is generated before it is truly seen. Many B2B websites get stuck before being indexed - it's not that the content is bad, it's that the paragraph structure and technical settings prevent the engine from reading them clearly. If you want to know where your content is leaking in this process, you can make an appointment for a 30-minute GEO diagnosis. We use Brand Radar to directly check your citation status in various AI engines.

Frequently asked questions

What is the difference between AI search and traditional SEO?
Traditional SEO competes for ranking position, while AI search competes for answers. The former compares keywords and link weights, while the latter uses vectors to compare semantics, and then the model generates answers from a few paragraphs, so the quality of paragraphs is more critical than the ranking of the entire site.
What is a RAG?
RAG is Retrieval Enhancement Generation. The system searches relevant documents in real time before answering, puts the content into the context of the model, and requires it to answer based on this information, thereby reducing obsolescence and fabrication, and allowing answers to be accompanied by source links.
Why is my content ranking well but not cited by AI?
The ranking means that you have been retrieved, but it does not guarantee that you will be selected for generation. If a passage cannot be read independently, the answer is unclear, or there is a lack of verifiable evidence, the rearrangement and generation stages will skip you and use better extracted sources instead.

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