A Plain-English Technical Guide Explains How LLMs and AI Agents Work

A comprehensive technical guide published on DEV Community breaks down how large language models (LLMs) such as ChatGPT, Claude, and Llama function under the hood. The guide targets engineers, curious learners, and interview candidates who want a deeper understanding of modern AI beyond surface-level usage. It walks through the full pipeline — from how raw text is split into tokens and converted to numbers, to how attention mechanisms, training, and fine-tuning shape model behavior. The article also covers advanced topics including retrieval-augmented generation (RAG), AI agents, multi-agent systems, safety guardrails, and production deployment. Written in plain English, it aims to serve as a single reference for understanding both the foundational concepts and real-world applications of LLM-based AI systems.