Retrieval-augmented generation (RAG), explained

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Retrieval-augmented generation (RAG) is a technique that gives a model  relevant information from external sources to help  the model generate the most accurate  answer. RAG allows models to use up-to-date , proprietary, and verifiable information rather than relying exclusively on knowledge encoded during training.

This guide explains the enterprise problems RAG solves, the components of a production RAG system, and advanced architectures such as multi-hop, agentic, multimodal, and structured data RAG. It also clarifies how RAG differs from search and fine-tuning and how governed enterprise content platforms can support grounded AI applications.

Key takeaways about RAG

  • RAG  gives AI systems access to proprietary content, current information, and sources that can support citations and audits
  • RAG can reduce hallucinations by grounding responses in retrieved evidence, but retrieval quality, content quality, permissions, and prompt design still affect reliability
  • RAG and fine-tuning are complementary: Fine-tuning changes how a model processes information, while RAG changes which information the model can access
  • Advanced RAG architectures can retrieve across multiple steps, critique draft answers, plan tool use, process multiple content formats, and query structured databases or APIs

What is retrieval-augmented generation?

RAG gives a generative model access to knowledge beyond what it memorized during training. Its central distinction is between two forms of memory:

  • Parametric memory is information encoded in the model’s parameters, or weights, during training
  • Non-parametric memory is stored outside the model and retrieved when it’s needed

A standalone language model generates responses primarily from patterns represented in its weights and information supplied directly in the prompt. A RAG system, by contrast, first searches an external source and selects relevant information, then inserts that information into the model’s context before generation.

A RAG-equipped system doesn’t have to know everything in advance; it can look up relevant information. This shift from exclusively memorized knowledge to retrievable knowledge is particularly valuable in enterprises, where facts, policies, products, and regulations change frequently.

Why RAG matters for enterprise AI

RAG paves the way for  knowledge workers to ask questions about enterprise information without requiring a model to memorize the entire knowledge base. It can surface relevant material at query time, synthesize information from multiple sources, and connect answers to the documents used to produce them.

Traditional search usually returns a ranked list of documents for a person to inspect. RAG, by contrast, sends retrieved information to a generative model which can reason across the material, synthesize  it, and produce a coherent response.

RAG isn’t just a search method . It combines semantic retrieval with generation, providing capabilities that neither a conventional search engine nor a standalone language model offered by itself.

Enterprise knowledge is distributed across:

  • Contracts
  • Policies
  • Wikis
  • Support tickets
  • Source code
  • Collaboration threads
  • Spreadsheets
  • Images
  • Other systems

Public language models generally haven’t been trained on this private material, while information learned during training may be incomplete or outdated. Effective RAG implementations combine retrieval quality with access controls, content governance, retention policies, source attribution, and auditable workflows.

RAG can also improve operational efficiency. Instead of placing an entire repository into a model’s context window for every query, the system retrieves a smaller set of relevant passages. This reduces unnecessary processing and improves the signal available to the model.

Core concepts in retrieval-augmented generation

How the RAG workflow works

Although RAG is often summarized as “retrieve, then generate,” a complete workflow involves several stages:

  1. Enterprise content is ingested from approved sources.
  2. Documents are parsed and divided into usable chunks.
  3. The chunks are converted into searchable representations and indexed.
  4. A user submits a question or request.
  5. The system interprets the query and retrieves likely matches.
  6. A reranker may reorder the results by relevance.
  7. The selected content is assembled into the model’s prompt.
  8. The model generates an answer grounded in that content.
  9. The system may verify the response, attach citations, and apply business formatting.
  10. Quality signals can be fed back into the retrieval process for future improvement.

Every stage affects the final answer. Even a capable language model can’t fully compensate for missing, outdated, inaccessible, or poorly retrieved source content.

Using proprietary enterprise data with RAG

Organizations possess large amounts of internal information that public models haven’t seen, including contracts, wikis, support tickets, source code, and collaboration threads. RAG connects this private knowledge to a generative model, and this access doesn’t require retraining the model whenever a document changes. Instead, an organization can update the underlying repository or index so that subsequent queries retrieve the newer, more accurate information.

How RAG provides current information beyond knowledge cutoffs

Every language model has a cutoff associated with the information that’s available during its training. This creates challenges involving changing regulations, live pricing, product updates, or other time-sensitive facts.

RAG addresses this limitation by retrieving the information that’s available at query time rather than depending only on information available at training time. Generated answers still depend on the freshness and quality of the connected sources.

How RAG reduces hallucinations through grounding

A hallucination is an AI-generated statement that sounds plausible but is unsupported or incorrect. In customer-facing, financial, legal, or compliance-sensitive work, these errors can create financial and reputational risks.

RAG reduces this risk by giving the model relevant source material on which to base its response. However, RAG doesn’t guarantee accuracy. Irrelevant retrieval results, contradictory documents, weak instructions, or poor source data can still lead to incorrect answers.

Source attribution, citations, and auditability in RAG

Regulated and high-stakes workflows often require users to see the evidence behind an answer. A RAG system can retain links between retrieved passages and their source documents, allowing an interface to display citations or supporting references.

This traceability helps users validate answers and supports review and audit processes. Citation quality depends on preserving source metadata throughout ingestion, retrieval, and generation.

Why RAG improves cost and context efficiency

Large context windows allow models to process more information in a single request, but sending all enterprise content to a model is generally expensive and inefficient. RAG selectively retrieves the information that’s most relevant to the current question.

Even a 10-million-token context window — roughly 7,500 pages of text — is small compared with enterprise knowledge bases that may contain millions of documents. This is closely tied to what Ben Kus, CTO of Box, described as context rot in a recent AI Explainer episode: "Context rot is the phenomenon that the more information that you give to AI, the more you fill up its context window, the more likely it is to give you inaccurate answers, because you've given it too much information... over time, the more details you give it, the more likely it is to have its attention become diluted, and it loses track of certain things."

Models can also experience a “context cliff,” in which retrieval and reasoning quality decline as the amount of supplied context grows, even before the context window is full.

How to ingest and process documents for RAG

Before content can be retrieved, the system must ingest and process source documents such as PDFs, spreadsheets, HTML pages, images, and other enterprise files. Processing usually includes extracting content, normalizing it, preserving metadata, and dividing it into chunks.

Chunking requires balance:

  • Chunks that are too small can lose surrounding meaning
  • Chunks that are too large can contain irrelevant information and reduce retrieval precision
  • Hierarchical chunking can preserve relationships between sections, pages, and full documents
  • Specialized handlers may be needed for tables, code blocks, forms, and images

Metadata such as document title, owner, date, content type, classification, and access permissions can improve both retrieval and governance.

Embeddings and vector databases in RAG

An embedding is a numerical representation that captures the meaning of a piece of content. Documents or chunks are converted into embeddings and stored in a system that supports fast similarity searches.

When a user asks a question, the query is also converted into an embedding. The system compares that query representation with indexed content to identify semantically related results.

The embedding model affects retrieval performance. Domain-specific models typically perform better than generic models in specialized enterprise applications, while the vector store must balance search speed, storage costs, update frequency, and scalability.

How RAG retrieves and interprets queries

Basic semantic retrieval finds content with embeddings that are similar to the user’s question. More advanced systems use hybrid retrieval, which combines semantic similarity with traditional keyword search.

Hybrid retrieval can capture both conceptual relationships and exact terminology. This is useful when queries contain product names, contract clauses, identifiers, technical terms, or acronyms that may require precise matching.

A retrieval system can also improve the query by:

  • Rewriting ambiguous questions
  • Expanding a query with related terms
  • Extracting important entities
  • Identifying the user’s intent
  • Applying metadata or permission filters
  • Breaking a complex question into smaller searches

Reranking results to improve retrieval relevance

The first retrieval pass usually produces a broad candidate set. Reranking applies more computationally intensive analysis, often through cross-attention models, to score those candidates against the query more precisely. The highest-ranked passages are then passed to the language model, and effective reranking keeps useful evidence from being buried beneath loosely related material.

How to integrate context and construct RAG prompts

Retrieved content must be assembled into a prompt the model can use. The prompt should distinguish source material from system instructions and user input so that the model understands what is evidence and what’s an instruction.

Context integration can also define:

  • How the model should handle missing information
  • Whether it should answer only from retrieved sources
  • How citations should be formatted
  • How conflicting sources should be treated
  • What output structure the business requires

Information placement matters, because models may give more attention to some positions in the context than others.

Generating and verifying grounded responses

The language model generates a response using both its trained capabilities and the retrieved material. A post-processing layer may then check claims against sources, insert citations, apply templates, or format the response for a business workflow.

More mature implementations measure generation quality and feed the results back into retrieval. This creates an improvement loop in which teams can identify weak queries, missing sources, poor chunks, or ineffective ranking.

How multi-hop RAG connects information across sources

Multi-hop RAG handles questions that require information from more than one source or retrieval step. The result of the first search informs a second search.

For example, to answer, “Where did the CEO who announced our new sustainability initiative go to college?” the system might first find the initiative and identify the CEO. It would then retrieve a different document containing that person’s educational background.

Self-reflective RAG for evaluating and improving answers

Self-reflective RAG evaluates a draft response before delivering it. If the system detects missing evidence, weak coverage, or low confidence, it can run another retrieval step focused on the identified gap. This feedback mechanism can catch blind spots before the answer reaches the user. Its effectiveness depends on how reliably the system evaluates its own evidence and output.

How agentic RAG plans retrieval and tool use

Agentic RAG gives the system more control over the sequence of actions it takes. 

As Kus explains, "Instead of having to specifically give the agent all those tasks ahead of time and tell it exactly what to do, which is hard and complex...you just say, this is the kind of thing I'm looking for, and here's a set of tools, even subagents to go do these things. Then it's able to then go through and accomplish that." 

Rather than following one fixed retrieve-and-generate workflow, the system can decide what to search, rewrite its query, assess the results, and use additional tools when needed.

An agentic system adapts its plan based on what it discovers. This flexibility can support complex tasks, but it also increases the need for permission controls, monitoring, evaluation, and limits on autonomous actions.

Using multimodal RAG with images, audio, and video

Multimodal RAG retrieves information from formats beyond plain text, including images, audio, and video. A manufacturing support application, for example, could retrieve both a wiring diagram and a written troubleshooting guide.

Different media types require specialized parsing and embedding models. The system must also align meaning across formats that don’t naturally share the same representation.

Kus broke down this technical process: "What's interesting is that, if you think about an image, it represents a bunch of pixels. And you can take little groups of these pixels, let's say a 16-by-16 block of pixels, put them into a long sequence with some positional information, then convert them to these tokens and feed them to the AI model." RAG uses processes like this one to parse information from multiple format types.

How structured data RAG works with databases and APIs

Structured data RAG connects a model to databases and APIs rather than relying solely on unstructured documents. It can support precise lookups, filters, calculations, and aggregations over tabular data.

Advanced implementations can interpret database schemas and infer joins, filters, and aggregations from a natural-language question. This allows users to interact with structured information without writing SQL, subject to appropriate controls and validation.

RAG vs. fine-tuning

RAG and fine-tuning solve different problems:

  • Fine-tuning changes how a model processes information or performs a task
  • RAG changes which external information the model can access at query time

The techniques can reinforce each other. For example, a model fine-tuned on legal terminology may interpret legal documents retrieved through RAG more effectively.

How to choose the right RAG architecture

No advanced RAG architecture is universally superior. The appropriate design depends on the organization’s priorities, including:

  • Answer accuracy
  • Response speed
  • Cost per query
  • Source traceability
  • Content freshness
  • Regulatory requirements
  • Supported content formats
  • Workflow complexity
  • Security and permission enforcement

Organizations can assemble RAG components independently or use an integrated platform. Modular components may include document parsing, instruction-following reranking, grounded generation, agentic retrieval, and end-to-end language model evaluation.

How Box approaches enterprise RAG

Box views effective enterprise RAG as both an AI problem and a content management problem. Retrieval quality depends on whether business content is centralized, current, correctly classified, accessible to the right people, and governed throughout its lifecycle. That’s why the Box approach starts with the content layer itself rather than the model.

Box AI applies generative AI directly to content stored in Box while enforcing existing Box permissions on every query. This maps directly to the retrieval methods and permission-filtering concepts described above. Rather than retrieving indiscriminately across a repository, Box AI ensures that only content a given user is already entitled to see can surface in a generated answer. That is the core promise of permission-aware retrieval.

Box Hubs lets teams curate a defined set of content, such as a project, policy area, or deal room, into a focused collection that AI can search. In RAG terms, a Hub narrows the retrieval domain before a query is issued. This reduces the number of irrelevant candidates entering the retrieval pass and improves the odds that reranking surfaces the right evidence, reflecting the chunking and query-understanding principles above.

As Jon Herstein, Chief Customer Officer at Box, describes, Box itself uses this pattern internally — "centralizing a lot of your support documentation to a Box Hub and then promoting that to users as a way for people to get more support in a self-service model." In RAG terms, a Box Hub narrows the retrieval domain before a query is issued.

Box Shield and Box Governance extend this control across the content lifecycle. Classification, retention schedules, and legal holds ensure that whatever a retrieval system can reach remains subject to the same security and disposition rules as the rest of the enterprise, addressing the auditability and access control requirements central to grounded AI.

For attribution and traceability, Box preserves metadata, version history, and ownership alongside the content itself. A citation traced back to a Box file points to a verifiable, permissioned source rather than an orphaned fragment. 

Box exposes this same secure content layer through the Box MCP Server and Box Platform APIs, allowing organizations to connect Box-governed content to third-party models and agents, including Claude, Copilot, Gemini, and others, without re-uploading files or duplicating the retrieval and permission logic for each new AI tool.

Once an answer is generated, Box Automate and Box Sign can carry that grounded output into a business workflow by routing an extracted or generated document for review, approval, or signature. Retrieval-augmented generation can then produce a well-cited response and a completed transaction.

From the Box perspective, an enterprise RAG strategy shouldn’t stop at selecting an embedding model or vector database. It should establish how content is created, secured, classified, retrieved, cited, reviewed, retained, and ultimately used in business workflows.

Frequently asked questions about RAG

What does RAG mean in artificial intelligence?

Retrieval-augmented generation is an AI architecture that retrieves relevant information from external sources before a language model generates a response. It combines the model’s trained knowledge with current or proprietary information supplied at query time.

How are parametric and non-parametric memory different?

Parametric memory is information encoded in a model’s weights during training. Non-parametric memory exists outside the model, such as in documents, databases, or APIs, and is retrieved when a query requires it.

Can RAG eliminate AI hallucinations?

No. RAG can reduce hallucinations by grounding responses in retrieved evidence, but it can’t guarantee accuracy. Poor source data, weak retrieval, conflicting documents, or incorrect interpretation can still produce unsupported answers.

How is RAG different from enterprise search?

Enterprise search generally returns documents or links for a user to review, while RAG feeds retrieved content into a generative model that synthesizes an answer. Search is a component of RAG, but RAG also includes context construction and response generation.

Can large context windows replace RAG?

No. Enterprise repositories can contain far more information than even very large context windows can hold, and processing all content for every query is costly and inefficient. Retrieval also filters noise so the model receives a smaller, more relevant evidence set.

Should organizations use RAG, fine-tuning, or both?

The choice isn’t necessarily either-or. Fine-tuning changes how a model performs a task or processes information, while RAG supplies the model with external information. Organizations can use both when a use case requires specialized behavior and current enterprise knowledge.

Can RAG retrieve information from images, audio, video, and databases?

Yes. Multimodal RAG can retrieve images, audio, and video using content-specific processing and embedding models, while structured data RAG can query databases and APIs. The general retrieve-and-generate pattern remains consistent, but indexing and context integration differ by data type.

Which part of a RAG system matters most?

No single component determines success because ingestion, chunking, embeddings, retrieval, reranking, prompting, generation, and governance all affect answer quality. In enterprise environments, content quality and permission enforcement are as important as model performance.

How can enterprises secure a RAG system?

Enterprises should enforce existing access permissions during retrieval, protect data in transit and at rest, preserve source metadata, and apply retention and legal hold requirements to indexed content. They should also monitor queries and outputs, evaluate answer quality, and limit agentic actions to approved tools and data.

When should organizations use basic vs. advanced RAG?

Basic RAG is appropriate when questions can be answered from a small number of clearly relevant sources. Multi-hop, self-reflective, agentic, multimodal, or structured data approaches become useful when questions require several retrieval steps, additional validation, multiple content types, or interaction with databases and tools.