langchain-rag-overview

Document the two-step and agentic approaches to Retrieval-Augmented Generation with LangChain for building Q&A systems over documents.

3|1|Updated Jan 31, 2026
One-click install
npx skills add https://github.com/christian-bromann/langchain-skills --skill langchain-rag-overview
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: langchain-rag-overview
Source: https://github.com/christian-bromann/langchain-skills/tree/main/skills/langchain-rag-overview/python
Command: npx skills add https://github.com/christian-bromann/langchain-skills --skill langchain-rag-overview

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

Retrieval Augmented Generation enables building QA systems that access external data sources to augment model responses, addressing limited context and stale knowledge.

Core Features & Use Cases

  • Two-Step RAG: retrieve then generate, suitable for straightforward QA over documents.
  • Agentic RAG: interactive, tool-assisted retrieval for complex, multi-step queries.
  • Use Case: Build Q&A systems over internal documents, websites, and knowledge bases with traceable sources.

Quick Start

Configure a basic RAG QA workflow over your document corpus.

Frequently Asked Questions about langchain-rag-overview

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
What is retrieval augmented generation in LangChain?

RAG solves limited context windows and stale model knowledge by enabling LLMs to access and cite traceable sources from internal documents, websites, and knowledge bases during generation.

How do I build a Q&A system over internal documents using LangChain?

LangChain supports implementing RAG for custom data sources by providing architectures for both Two-Step and Agentic patterns, allowing you to retrieve context and generate responses over your document corpus.

When should I use Agentic RAG instead of a Two-Step RAG pattern?

You should choose Agentic RAG over Two-Step RAG when your queries require interactive, multi-step reasoning and tool-assisted retrieval, rather than simple linear document retrieval and generation.

Does LangChain RAG support querying custom websites and knowledge bases?

LangChain RAG can query custom websites and knowledge bases by retrieving data from these external sources to augment model responses, ensuring answers are grounded in your specific corpus.

What are the limitations of using retrieval augmented generation for Q&A?

RAG limitations depend on the retrieval quality from your vector store and the chosen architecture; Two-Step RAG handles straightforward queries but may struggle with complex multi-step questions better suited for Agentic RAG.