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The GEO Handbook, Part 3: LLMs, Prompts, Tokens, Chunks and Embeddings Explained

How does a question become an AI answer? Part 3 explains LLMs, prompts, tokens, context windows, chunks, embeddings, grounding and RAG, then connects them to content, testing and cost.

Editorial review:

Reviewed on 13 October 2026 against official documentation and primary sources. Two visuals are unmeasured concept models. Anthropic test results are labelled as external measured data. The Lucerne fiduciary example is fictional; example values are not benchmarks.

GlasBox GEO Handbook Part 3: from a question through sources and context to a generated answer.

GEO becomes easier once you can trace the path from question to answer. Part 3 explains LLMs, prompts, tokens, context windows, chunks, embeddings, grounding and RAG without technical fog. You will then know what your website must do.

By Kacper Ruta · GlasBox Studio, Malters/Lucerne · Reviewed: 13 October 2026.

Part 3 of the GlasBox GEO Handbook builds on the sustainable strategy from Part 2. We now open the machine only as far as your business needs. Part 4 will separate mentions from citations and explain how to measure both.

A model is not a product

An LLM generates language. The chat interface, search, tools and source access belong to the product layer.

Context is not truth

A large context window holds plenty of material. False or conflicting documents remain false.

Structure serves people

Clear sections help readers and may help retrieval. Artificial text fragments are not a GEO shortcut.

Short definition: A generative answer system combines a language model with instructions, context and sometimes retrieved sources to produce a new answer.

01 — Which terms do you actually need for GEO?

GEO requires eight core terms and a clear view of the process. The mathematics can stay in the engine room. You must still recognise where information enters, disappears or gains an unsupported addition.

Imagine a supplier explaining your business with twelve technical terms but no decision path. Ask them to show every term against one real customer question. If the answer stays vague, a polished dashboard will not rescue it.

TermShort meaningRelevance to GEO
large language model (LLM)generates language from learned patternsformulates the answer
promptprovides the task and contextdefines the immediate question
tokenis a processing unitaffects volume and cost
context windowcontains the usable working contextlimits material and output
chunkis a retrieved content passagecarries one piece of information
embeddingrepresents meaning as a number vectorenables similarity search
groundingties an answer to sourcesreduces unsupported additions
RAGretrieves sources before generationbrings current data into the prompt

Google defines these terms in similar ways in its current machine-learning glossary, although products implement them differently. [1] For management, the process matters more than a brand name.

02 — An LLM is the engine, not the whole vehicle

A large language model is a trained model that processes and generates probable token sequences. A product adds the interface, search, file access, tools, rules and source display. Confusing both layers leads to weak GEO conclusions. [1][2]

Suppose one product run uses no web search while another retrieves current sources. The answers may differ even when the technical engines are related. Your brand therefore meets a complete system, not merely a model.

LayerJobExampleGEO question
modelprocess and generate languageselected language or multimodal modelwhich knowledge and context are available?
productcontrol use and toolsChatGPT, Claude, Google Search with AI featuresdoes it search, cite or only generate?
answer runhandle one requesta chat with history and sourceswhat information was available this time?
your sourceprovide a verifiable claimservice page, study, profile or documentis the claim correct, reachable and clear?

Model names and product features change faster than your company information. Anchor the strategy in reliable sources rather than a version number.

03 — How does an AI answer emerge in simple terms?

An AI answer emerges through input, context, possible retrieval, selection and generation. No provider reveals every internal step. The following model therefore maps the parts you can inspect, not a secret algorithm.

Concept model: an AI answer moves through prompt, context, retrieval, selection, generation and verification.
Schematic path to a generated answer; not a measurement of a specific product.

A system splits inputs into tokens and processes them within the available context. When a product retrieves external information, it selects useful passages and adds them to that working context. The model then generates the answer step by step. [3][5][6]

Not every answer run uses the web, the same search or identical sources. A repeated test can therefore return another result. GEO monitoring should record the prompt, product, date, language, location and visible sources.

Why a short explanation of Transformers and self-attention is enough

A Transformer is a neural architecture that processes relationships within token sequences through attention mechanisms. Self-attention estimates which parts of the available context matter for other parts. [1][10]

One practical GEO rule follows: a term needs the right neighbouring context. ‘Payroll’ alone remains open. ‘Payroll administration for a limited company in Lucerne’ joins the task, company form and region.

Test rule: Ask three questions about every claim: which input, which context and which source were present? Without those details, an AI answer is difficult to audit.

04 — How do training, context and live retrieval differ?

Training shapes the model, context supplies one answer run, and retrieval brings in selected external information. Each layer operates at a different time and carries different risks. Separating them makes content planning more realistic.

Training data includes text, code, images or other material from which a model learns patterns. Training does not create a tidy, searchable bibliography inside the model. A later answer cannot automatically identify the training document behind a phrase.

What parameters and self-supervised learning mean

A parameter is a learned numerical value that helps shape model behaviour, not a stored paragraph. Self-supervised learning derives learning signals from the data itself. Neither parameter count nor training method reveals whether a product will retrieve your current page. [1]

LayerTimingWhat it providesTypical risk
trainingbefore uselearned patterns and capabilitiesstale, incomplete or biased patterns
contextduring the requestprompt, history, files and toolsexcessive, conflicting or disordered material
retrievalduring the requestselected external passageswrong source or unsuitable passage
generationduring the answernewly composed outputplausible addition without enough evidence

Inference means using a trained model to produce a specific output. This phase matters most to your SME because the question, product rules, current sources and model behaviour meet here.

05 — Why can a convincing answer still be wrong?

A hallucination is a plausible-sounding output that is factually wrong or unsupported. Confident language does not prove truth. Names, figures, dates, quotations and URLs deserve independent checks. [1][2]

Imagine an answer about forming a limited company in Lucerne. The process and tone sound professional, yet a deadline or authority address is invented. The error hides because the prose raises no alarm.

ClaimRisk without a sourceSafer response
general explanationmediumcheck a representative sample
current price or deadlinehighopen the original source and date
legal or tax obligationvery highrequire review by the responsible expert
verbatim quotationhighlocate the wording in the original
URL or contact detailhighopen the link and inspect the destination

Tokenisation does not automatically cause false URLs. An invented path appears when a model generates a convincing character sequence without reliable retrieval. The slash is innocent; missing verification is not. [2][7]

  • Open every stated URL.

  • Compare figures with the original source.

  • Check the region, date and scope.

  • Require expert approval for legal, financial and health claims.

  • Allow the system to state that information is missing.

  • Store the prompt, answer, sources and review date.

06 — Grounding and RAG reduce risk but cannot remove it

Grounding ties an answer to supplied or retrieved source material. Retrieval-augmented generation, or RAG, first finds relevant information, adds it to the prompt and then produces an answer. [1][6]

Suppose a system must explain your current onboarding list. RAG can retrieve the right page instead of relying only on training patterns. The answer can therefore become fresher and easier to inspect.

StepSystem taskYour task
1understand the requestknow the real customer question
2retrieve sourceskeep the page reachable and unambiguous
3select passageswrite claims with their context
4augment the contextstate date, region and limits
5generate the answerinspect both wording and source
6enable actionprovide a working next step

OpenAI describes semantic retrieval through vector stores, while Google explains RAG as a common grounding technique. Both descriptions expose the same principle: retrieval and generation are separate steps. [5][6]

Why a retrieved source is not yet proof

Grounding can reduce false output but cannot eliminate it. A source may be stale, a passage may lose context, or the answer may summarise it incorrectly. Anthropic therefore recommends uncertainty, supporting passages and further verification. [7]

A displayed source first proves only that a visible relationship exists. Part 4 on mentions and citations will test whether the linked page supports the specific claim.

07 — A good prompt is a brief, not a truth machine

A prompt is the input that sets the task, context and desired response format. A precise prompt improves fit. It cannot repair missing facts or weak sources. [1]

The weak prompt ‘What does a company need for payroll?’ leaves the region, legal form and goal open. A better prompt states the Lucerne company, twelve employees, transition date and required result.

ComponentWeakBetter
roleno guidancefor a managing director without jargon
task‘explain payroll’prepare a payroll-administration handover
contextno detailsLucerne limited company, twelve employees
boundaryunrestricted answerstate any missing facts clearly
formatunspecifiedchecklist with sources and next step
freshnessunclearverify as of 13 October 2026

Anthropic recommends clear structure, relevant examples and distinct source sections for complex tasks. [7] The same principle applies internally: give colleagues a sound brief before polishing the prompt.

  • Name the audience, task and required decision.

  • Provide the region, date and relevant starting point.

  • Separate instructions, sources and examples visibly.

  • Request evidence for verifiable claims.

  • Allow an honest ‘not enough information’ response.

  • Define the format, length and next step.

Your internal template prompt is not the real GEO target. The many questions asked by real people matter more. Your content must remain useful even when nobody uses your perfect briefing.

08 — Tokens and context windows govern space, cost and focus

A token is a unit into which a model splits inputs and outputs. The context window is the complete working space available for one answer run. Both vary across models and products. [3][4]

Concept model: the context window holds instructions, conversation, documents, retrieved evidence and room for the answer.
Concept model of a context window; size and use depend on the product.

A token may represent a character, word part, word or punctuation mark. Word count and token count are therefore different. Language, spelling, encoding, images and tool data change usage. [3]

A context window works like a desk, not an unlimited company archive. System instructions, conversation history, files, search results, tool output and the new answer share the available space. [4]

ComponentUses context?Management consequence
system instructionsyeskeep rules short and clear
conversation historyusuallyold branches can distract
uploaded documentsyesprovide only relevant versions
retrieved chunksyesrecord selection and origin
tool resultsyeslimit and structure raw data
generated answeryesleave enough output space

API costs may price input, output, cached and reasoning tokens separately. Current rates change and do not belong in a permanent GEO rule. Measure total consumption on representative tasks instead of comparing only list prices. [3]

Why more context does not guarantee more quality

A larger window allows longer documents, but irrelevant context can obscure important evidence. Anthropic calls this quality loss as context grows ‘context rot’. Selection still matters more than raw volume. [4]

Do not provide an entire drive when preparing a proposal. Supply the current service description, valid pricing, exclusions and two suitable examples. The AI needs a clear desk, not a digital attic.

09 — A useful chunk carries meaning and boundaries together

A chunk is a coherent content passage that a retrieval system can store or select. Useful chunks contain enough context for correct interpretation. The product still controls the exact boundaries.

Suppose a passage says only ‘The deadline is 30 days’. Without an event, region and date, the figure is useless. A robust section states what the deadline covers and where the authoritative source sits.

PassageRetrieval valueReason
‘The deadline is 30 days.’weakevent and scope are missing
‘For this internal handover plan, allow 30 days.’betterpurpose and example status are clear
heading plus self-contained answerstrongtopic and claim stay connected
table without an introduction or unitweakcolumns lose meaning outside the page
figure with region, period and sourcestrongclaim remains verifiable

Anthropic showed in its own retrieval tests that missing document context can weaken chunks. The following table reproduces its published failure rates for retrieval within the top 20 results. [8]

Tested methodTop-20 retrieval failureRelative reduction
embeddings5.7%baseline
contextual embeddings plus BM252.9%49%
additional reranking1.9%67%

The figures come from the domains and configurations tested by Anthropic. They document that retrieval experiment, not a general GEO effect or an expected value for your website.

Why you should not cut your website into artificial mini-chunks

Google does not require artificial micro-passages for its generative Search features. Its systems can understand several topics on one page. Page and section length should therefore follow the audience and subject. [9]

Good structure still matters because people need headings, paragraphs and tables. Keep one central thought per section, while retaining its definition, scope and limitation together.

  • Open each section with a complete core claim.

  • State the subject, region and period when they alter meaning.

  • Keep a heading beside its corresponding answer.

  • Explain abbreviations at first use.

  • Give tables an introduction, unit and conclusion.

  • Avoid pronoun-heavy paragraphs without a clear referent.

  • Write for readers, not a guessed chunk length.

10 — Embeddings find meaning, not automatic truth

An embedding is a numerical representation that lets systems compare content for similarity. Related meanings may sit close together despite sharing few words. Proximity signals relevance, not accuracy or quality. [1][5]

A query for ‘payroll handover for a small Lucerne limited company’ may retrieve payroll-onboarding content. The exact phrase need not appear. Domain, legal form, region and working step jointly shape meaning.

TermWhat it isWhat it does not prove
embeddingnumerical representation of contentsubject-matter accuracy
vectorthe resulting number sequencemeaning that humans can read
vector spacecomparison space for representationsa public map of the system
vector storeindex for those representationsautomatic source quality
similarity scorecomputed proximity to a queryapproval or recommendation

Multimodal systems can also turn images, audio or video into processable representations. [1] GEO needs no special rule in response: the image, caption and surrounding text should carry the same real claim.

OpenAI describes semantic search as a method that can find suitable content despite few shared keywords. Its search results include relevant chunks, similarity scores and the source file. [5]

Why keywords remain useful

Semantic search does not replace clear wording. Names, product codes, places, standards and specialist terms often supply decisive precision. A system can expand meaning, but it should not need to guess your company name.

Write naturally and precisely. State the service, audience, Lucerne, language and boundaries where they belong. Do not repeat terms mechanically; add useful information instead.

11 — Conversation turns a keyword into a decision path

Conversational systems retain parts of the earlier exchange as context and answer follow-up questions from it. One chat can therefore move a customer from orientation through comparison to action. [1][4]

Imagine a managing director who first asks about payroll administration. She then adds twelve employees, two cross-border workers and a January transition. Every follow-up changes the suitable answer and potential source selection.

Conversation stageExample promptRequired information
understand‘What does outsourced payroll cover?’scope and definitions
narrow‘Does it suit twelve employees in Lucerne?’audience, region and limits
compare‘What remains in-house?’roles and handover points
verify‘Which documents are needed to begin?’current checklist and source
act‘How does an initial meeting start?’contact route, preparation and appointment

A classic keyword list captures only part of this path. Build a prompt panel containing opening questions, follow-ups and objections. Use it for testing, not for producing dozens of near-duplicate pages.

Why local Lucerne details must appear early

Local suitability often depends on small facts: service area, language, meeting format, travel and responsibility. Do not bury them in the footer. Connect each detail with the relevant service and action.

Google names maintained business details and a Google Business Profile as foundations for local visibility. [9] A profile cannot replace a clear service page; both must describe the same real business.

12 — Lucerne example: From thin copy to a reliable answer source

This fictional example continues the Lucerne fiduciary firm from Parts 1 and 2. Example values are not benchmarks. The team rebuilds its ‘Payroll administration’ page without promising an AI recommendation.

The starting point

The existing page contains a sales paragraph and a contact form. It states no audience, handover process, required documents, exclusions, responsible expert or review date. People must ask, and retrieval systems find few self-contained claims.

Reviewed fieldStarting value in the exampleRisk
clear core claims2 of 12answer remains generic
claim with a region0 of 12local suitability remains open
claim with a visible source1 of 12freshness is hard to inspect
defined next step1 of 3action path breaks
named responsible person0maintenance remains unclear

The baseline covers only twelve predefined claims and three action paths. It does not measure a GEO ranking. The team can still compare the page cleanly after the revision.

The revised page structure

The new page opens with an answer: who the service fits, what it includes and where it applies. Handover, documents, limits, expert contact, sources and booking follow. Each section resolves one customer question.

SectionOpening claimRequired detail
suitabilitywhich firms the service fitsregion, size and language
scopewhich tasks are coveredinclusions and exclusions
handoverhow the transition workssteps and responsible people
documentswhat the firm must providelist, format and timing
limitswhen further advice is neededclear escalation point
contacthow the first meeting startsperson, channel and preparation

The structure is not a secret ranking factor. It reduces information loss for people and creates complete sections for different retrieval paths.

The three-layer test

LayerTestPass condition
sourcereview twelve core claims on the pageevery claim correct, dated and approved
answerrun a fixed prompt panel in defined productsclaim and boundary reproduced correctly
actionopen visible links and contact pathsdestination works on mobile in DE-CH and EN

The team tests ten documented conversation paths under identical starting conditions. Ten is a GlasBox example size, not an industry standard. Each run stores the prompt, product, language, date, answer and visible sources.

Nobody can guarantee that a product will use the page. The team can guarantee that its own source is correct, understandable and reviewable. Responsible GEO begins there.

Result after testingDecision
source correct, answer correctobserve and repeat regularly
source correct, answer wronginvestigate retrieval, context and product limits
source unclear, answer wrongrepair the source first
answer correct, action brokenrepair the contact or conversion path
result variesincrease the sample and claim no effect

The result table blocks one comfortable excuse: a correct answer cannot repair a broken contact path. GEO ends with verifiable customer utility, not with polished prose.

13 — What should you do on Monday morning?

On Monday, choose one important service and follow one customer question through to action. One morning is enough for an initial diagnosis. Do not produce twenty new pages yet.

  • Choose one revenue-relevant service with clear responsibility.

  • Write down five real opening questions and five follow-ups.

  • Mark the answer, region, date, boundary and contact path on the page.

  • Open every cited original source and every link.

  • Rewrite the first paragraph as a self-contained answer.

  • Review every section for complete context.

  • Test three documented conversation paths in one defined product.

  • Store errors as tasks with a responsible person and deadline.

Then allow one week for expert approval, technical checks and the English adaptation. A wider prompt panel becomes worthwhile only after the core source is sound.

GlasBox working rule: Repair the source first, retrieval second and presentation last. Otherwise you are polishing an answer on uncertain foundations.

14 — Frequently asked questions

The recurring questions concern practical boundaries more than mathematics. These answers deliberately separate the technology, source and business effect.

Must I understand how a neural network is trained?

No. For GEO, you need the path through input, context, retrieval and answer. Model training matters when you build or assess the systems themselves.

Is ChatGPT the same as GPT?

No. ChatGPT is a product, while GPT names a model family. The product can add search, tools, rules and interfaces.

Does RAG prevent every hallucination?

No. RAG can supply current, reviewable information, but retrieval and summarisation can still fail. Critical claims require checking against the original.

Does every page need short chunks?

No. Google does not require artificial micro-sections for its generative Search features. Write complete, clearly organised answers at the length people need. [9]

Are embeddings a new ranking factor?

No. Embeddings are a representation and similarity-search technique. Their use proves neither a confirmed ranking factor nor a guarantee of a mention.

How long should a good prompt be?

As long as necessary and as short as possible. The goal, context, boundaries, sources and format must be clear. Repetition without new information only consumes attention and tokens.

Can a large context window replace our knowledge base?

No. A large window holds more material but manages neither validity nor responsibility. Your knowledge base still needs versions, sources, access rules and review cycles.

Why do identical prompts produce different answers?

Several factors may change: model, product, conversation history, search results, selection, system rules and generation. Record every test run in full.

15 — Conclusion: GEO starts with the path to an answer

GEO becomes manageable when you separate the model, product, context, retrieval and source. An LLM generates language, grounding supplies material, chunks carry passages and embeddings help retrieval. No single component proves truth.

You cannot open the platform, but your source remains reviewable. Verify claims, boundaries and dates, then document every answer run. Part 4 will show when a brand is merely mentioned and when a source receives a genuine citation.

The rule for Part 3: Do not optimise for a guessed algorithm. Build complete, current and verifiable information for people, then test how systems retrieve and reproduce it.

Sources and editorial basis

Technical definitions and product claims use the following primary sources, reviewed on 13 October 2026. The process model, Monday checklist and Lucerne example are GlasBox methods. Two diagrams are unmeasured concept models; the sole results table uses clearly bounded Anthropic test data.

The next step

Are your pages understandable, retrievable and verifiable?

We clarify your starting point, the most important sources and the next verifiable step. We agree the scope and deliverables of any audit in the proposal.

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