The latest articles on DEV Community by Kamil Tustanowski (@kamil_tustanowski_8d33739). https://dev.to/kamil_tustanowski_8d33739 https://media2.dev.to/dynamic/image/width=90,height=90,fit=cover,gravity=auto,format=auto/https:%2F%2Fdev-to-uploads.s3.amazonaws.com%2Fuploads%2Fuser%2Fprofile_image%2F3766744%2Fa32bf4cc-bf79-48c2-8c20-9b0f1884516c.jpg https://dev.to/kamil_tustanowski_8d33739 en Kamil Tustanowski Wed, 11 Feb 2026 16:16:47 +0000 https://dev.to/kamil_tustanowski_8d33739/ai-agents-101-from-concept-to-code-no-frameworks-required-5cgd https://dev.to/kamil_tustanowski_8d33739/ai-agents-101-from-concept-to-code-no-frameworks-required-5cgd <p>Most tutorials about AI agents rely heavily on frameworks.<br> LangChain.<br> AutoGen.<br> CrewAI.</p> <p>They’re powerful — but they abstract away the most important part:<br> How an AI agent actually works under the hood.</p> <p>So I decided to build one from scratch.</p> <p>No frameworks.<br> Just Python, an LLM, and a clear decision loop.</p> <p>What This Article Covers<br> In this write-up, I walk through:</p> <ul> <li>What makes an AI agent different from a plain LLM</li> <li>The core “Think → Act → Observe” loop</li> <li>How tool calling works conceptually</li> <li>How to structure a simple agent controller</li> <li>How to let an agent browse and retrieve information</li> <li>A fully working example at the end</li> </ul> <p>The goal wasn’t to build something production-ready.</p> <p>The goal was to understand the mechanics deeply.</p> <p>Why Build Without Frameworks?<br> Frameworks are great for speed.<br> But if you:</p> <ul> <li>Want to customize behavior</li> <li>Need fine-grained control</li> <li>Are debugging weird agent decisions</li> <li>Or simply want to understand what's happening</li> </ul> <p>Then building one manually is incredibly valuable.<br> Once you understand the loop, frameworks make much more sense.</p> <p>If you're interested in how AI agents really work and want a practical, code-first explanation, you can read the full article here:</p> <p>👉 <a href="https://medium.com/@kamil.tustanowski/ai-agents-101-from-concept-to-code-no-frameworks-required-2dfdaf66b6c1" rel="noopener noreferrer">https://medium.com/@kamil.tustanowski/ai-agents-101-from-concept-to-code-no-frameworks-required-2dfdaf66b6c1</a></p> <p>Would love feedback — especially from people building agent systems in real-world projects.</p> ai python opensource machinelearning