Agentic AI Crash Course using LangChain | LangChain Crash Course
At a glance
- Length
- 2 hr 24 min
- Channel
- codebasics
- Video from
- May 2026
- Rating
- ⭐⭐ Great video · 2/2
- Best for
- Developers learning to build autonomous AI agents and multi-model systems.
What this video answers
- What's the difference between a traditional AI system and an agentic AI system?
- Do I need to be an expert in transformers to follow along?
- Which LLMs does the course use?
- Can I apply this to my own business problem immediately?
- What tools do I need to install to code along?
Understanding Agentic AI and LangChain Fundamentals
This crash course explores the intersection of generative AI and agentic systems, building from theoretical foundations to working implementations. The video walks through what makes modern large language models tick—covering transformer architecture, how LLM parameters shape output, and why these concepts matter—before diving into practical code using LangChain. Rather than staying abstract, the instructor demonstrates each concept hands-on, starting with basic API calls and progressing to multi-agent systems.
The scope is substantial: foundational theory occupies the first half, while the second half focuses on two complete projects that mirror real-world use cases. A shopping agent and a telecom customer support chatbot serve as the capstone, each combining multiple tools and techniques taught earlier. The course emphasizes that understanding the "why" behind agentic behavior—particularly the ReAct loop that governs agent decision-making—is essential before building with it.
Key Moments
Key Strengths and Technical Coverage
- Layered progression: Moves logically from generative AI basics through transformer architecture and LLM mechanics before introducing agents, so viewers build mental models step by step rather than jumping into complexity.
- Hands-on vector database and RAG work: Vector database setup and retrieval-augmented generation are demonstrated practically, not just explained theoretically, using ChromaDB and sentence transformers to show retrieval in action.
- Multi-modal and multi-agent examples: The video goes beyond single-model setups, covering how to work with multiple LLMs (Qwen, Gemini, Llama Vision) and how agents coordinate with one another in real workflows.
- Guardrails and evaluation sections: Addresses production concerns—not just how to build agents, but how to evaluate them and add safety guardrails that prevent unintended behavior.
- Real project implementations: Two complete projects (shopping agent and telecom RAG chatbot) use a practical stack (Streamlit, SQLite, HuggingFace) that learners can adapt to their own work.
- No-code alternative included: Acknowledges that not everyone codes; a no-code agent segment and linked resources let non-developers explore agentic AI concepts.

Who Should Take This Course
This course suits developers and data professionals who want to move beyond simple chatbots into autonomous AI systems. If you've used basic LLM APIs or played with prompt engineering but don't yet understand how agents decide what to do next—or how to combine multiple models into a cohesive system—this provides the bridge. It's also relevant for product managers or technical leads evaluating whether agentic AI fits a business problem, since the theoretical groundwork makes the trade-offs clear.
The prerequisite is comfort with Python and some familiarity with APIs; the course doesn't teach programming basics. If you're new to AI entirely, the generative AI overview helps, but you'll benefit most if you've already experimented with an LLM or two. The no-code section makes a small portion accessible to non-programmers interested in the concepts.
Common Questions About This Agentic AI Training
What's the difference between a traditional AI system and an agentic AI system?
Traditional AI follows pre-defined rules and paths; it does what it was explicitly programmed to do. Agentic AI observes its environment, reasons about possible actions, and chooses what to do next—often iterating based on results. The video explains this distinction early and shows how the ReAct loop (reasoning, acting, observing) enables autonomous decision-making.
Do I need to be an expert in transformers to follow along?
No. The video includes an explainer on transformer architecture and uses an analogy-based explanation to make the concept accessible. You don't need to implement transformers yourself; understanding what they do and why LLM parameters matter is sufficient for building agents.
Which LLMs does the course use?
The projects leverage multiple models: Gemini, Qwen, and Llama Vision. Using different models shows how to swap LLMs without redesigning your agent, a practical skill since model availability and pricing change frequently.
Can I apply this to my own business problem immediately?
Yes, if your problem involves information retrieval, decision-making, or multi-step workflows. The shopping agent and telecom RAG chatbot are realistic enough to adapt; the shopping agent logic transfers to e-commerce or inventory systems, while the RAG chatbot pattern applies to customer support, internal knowledge bases, or FAQ automation.
What tools do I need to install to code along?
The stack includes LangChain, ChromaDB for vector storage, Streamlit for interfaces, SQLite for data, HuggingFace models, and sentence transformers for embeddings. API keys for at least one LLM provider (Gemini, OpenRouter, or similar) are required. The video covers API setup early so you're not blocked.

Key Terms
- Generative AI
- Machine learning systems trained to generate new content—text, images, or other outputs—based on patterns learned from training data.
- Transformer Architecture
- A neural network design that uses attention mechanisms to process and understand relationships between words or tokens in a sequence.
- Retrieval-Augmented Generation (RAG)
- A technique where an AI system retrieves relevant information from a database or knowledge base before generating a response, improving accuracy.
- Vector Database
- A database optimized for storing and searching high-dimensional numerical representations of data, enabling fast semantic similarity lookups.
- ReAct Loop
- The reasoning, acting, and observing cycle that allows an AI agent to think about a problem, take an action, and learn from the result.
- Multi-Agent System
- A setup where multiple AI agents work together, each handling different tasks or domains, coordinating to solve larger problems.
- LLM Parameters
- Configuration values in a language model that control behavior like creativity, response length, and determinism of outputs.
Sources: Generative AI · Transformer Architecture · Retrieval-Augmented Generation (RAG) · Vector Database · ReAct Loop · Multi-Agent System · LLM Parameters — definitions cross-referenced with Wikipedia
Video by codebasics on YouTube. If you enjoyed it, please subscribe to their channel and show your support for the great video.
Description
A complete crash course on agentic ai using langchain. This is also a course on generative AI. In this video, we will discuss theoratical foundations of generative AI and agentic AI. Langchain will be used for hands on programming. We will then build two projects (1) shopping agent (2) telecom RAG chatbot using langchain, chromadb, llama vision model, Qwen, gemini LLMs, streamlit, sqlite, huggingface and sentence transformers.
Download the resources here: https://codebasics.io/resources/agentic-ai-crash-course
No code agents: https://codebasics.io/ - Check "Our Live Cohorts" section
Langgraph tutorial: https://youtu.be/CnXdddeZ4tQ
Customer care support: https://youtu.be/Jekzc6BM5_w
Workflow automation: https://youtu.be/QBI5bmbgL38
Check out OpenRouter: https://openrouter.plug.dev/6QpCcgh
Codebasics AI Pro keeps you ahead of it: weekly tool tests, live build sessions, and AI you can actually apply at work: https://codebasics.io/ai-learning-for-professionals
⭐️ Timestamps ⭐️
0:00:00 Intro
0:01:53 What is Gen AI
0:03:10 Traditional AI
0:05:41 Transformer Architecture
0:11:13 LLM Parameters
0:13:28 LLM Analogy Based Explanation
0:18:41 API Key Setup
0:21:01 Simple LLM call using LangChain
0:41:50 RAG Theory
0:47:52 Vector DB - Hands On
0:53:50 Rag - Hands On
1:02:54 AI Agent Intro
1:03:31 What is an AI Agent
1:10:18 ReAct Loop
1:10:49 AI Agent Hands on
1:21:28 Multi-Agent system
1:21:48 Multi-Model Agent theory
1:23:31 Multi-modal agent – hands on
1:29:28 Evaluation
1:34:07 Guardrails
1:36:41 Project 1 – Shopping Agent
2:06:57 Project 2 – Telecom RAG
2:22:46 No Code Agents
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