Tutorials ASP.NET Core with Agentic AI Tutorial

RAG Fundamentals — Complete Guide

RAG Fundamentals — Complete Guide: free step-by-step lesson with examples, common mistakes, and interview tips — part of ASP.NET Core with Agentic AI Tutorial on Toolliyo Academy.

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ASP.NET Core with Agentic AI Tutorial · Lesson 41 of 100

RAG Fundamentals

AI basics ✓Agents

Agents · 2 — Build · ~6 min · Module 5: RAG and Vector Databases

What is this?

RAG (retrieval-augmented generation) fetches relevant documents before the LLM answers. AgentNest CRM copilot retrieves account playbooks; hospital assistant pulls protocol PDFs from vector stores.

Why should you care?

Models hallucinate policy without grounding; RAG ties answers to tenant knowledge bases.

See it live — copy this example

Paste into an ASP.NET Core 8+ / AgentNest project, then run with dotnet run (set your API keys in user-secrets).

// AgentNest.Rag/RagPipeline.cs
public sealed class RagPipeline(IEmbeddingGenerator embedder, IVectorStore store, IChatClient chat)
{
    public async Task<string> AskAsync(string tenantId, string question, CancellationToken ct)
    {
        var vector = await embedder.GenerateEmbeddingAsync(question, cancellationToken: ct);
        var hits = await store.SearchAsync(tenantId, vector, topK: 5, ct);
        var context = string.Join("\n---\n", hits.Select(h => h.Text));
        var prompt = $"Use only this context:\n{context}\n\nQuestion: {question}";
        return (await chat.GetResponseAsync([prompt], cancellationToken: ct)).Text;
    }
}

What happened?

  • RagPipeline embeds the question, searches tenant vectors, injects hits into the prompt, then generates the answer.
  • Follow the steps below — typing the code yourself is the fastest way to learn.

Practice next

  1. build IVectorStore abstraction in AgentNest.Rag.
  2. Index CRM PDFs per tenant with embedding batch jobs.
  3. Add RagPipeline to DI and expose POST /api/rag/ask.
  4. Add reranker step after vector search.
  5. Return citations array alongside answer text.

Remember

RAG = retrieve relevant chunks, then generate with context. Always filter vector search by tenantId. Log chunk IDs for traceability in AgentNest.

CRM playbook answers

Reps ask how to handle enterprise discount requests.

Outcome: RAG pulls approved playbook sections instead of inventing pricing policy.

Interview prep for this lesson

Practice these questions aloud after reading—each links to a full structured answer.

Junior Detailed
Explain Concepts in the context of ASP.NET Core with Agentic AI.
Short answer: Interviewers want a crisp definition, a practical example from your projects, and awareness of trade-offs—not textbook dumps. Explain a bit more How to structure your answer (60–90 seconds) Define Concepts…
Mid Detailed
What are common mistakes teams make with LLMs when using ASP.NET Core with Agentic AI?
Short answer: Interviewers want a crisp definition, a practical example from your projects, and awareness of trade-offs—not textbook dumps. Explain a bit more How to structure your answer (60–90 seconds) Define LLMs in p…
Senior Detailed
How would you debug a production issue related to RAG in a ASP.NET Core with Agentic AI application?
Short answer: Interviewers want a crisp definition, a practical example from your projects, and awareness of trade-offs—not textbook dumps. Explain a bit more How to structure your answer (60–90 seconds) Define RAG in pl…
Junior Detailed
Describe a real-world scenario where Production mattered in a ASP.NET Core with Agentic AI project.
Short answer: Interviewers want a crisp definition, a practical example from your projects, and awareness of trade-offs—not textbook dumps. Explain a bit more How to structure your answer (60–90 seconds) Define Productio…
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ASP.NET Core with Agentic AI Tutorial
Course syllabus

ASP.NET Core with Agentic AI Tutorial

Module 1: AI and Agentic AI Foundations
Module 2: ASP.NET Core AI Fundamentals
Module 3: Semantic Kernel
Module 4: AI Agents and Multi-Agent Systems
Module 5: RAG and Vector Databases
Module 6: AI Security and Observability
Module 7: Cloud-Native AI and DevOps
Module 8: AI SaaS and Enterprise Systems
Module 9: AI System Design and Architecture
Module 10: Enterprise AI Projects
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