Build a Working AI Agent Without the Frameworks

👉 Frontend System Design Essentials — Course: https://icodeit.thinkific.com/courses/frontend-system-design-essentials 👉 Frontend System Design Essentials — Book: https://leanpub.com/frontend-system-design-essentials/ Intro If “AI agents” sound abstract, this walkthrough makes the mechanics concrete. We start with a tiny Node.js REPL—read input, act, repeat—then swap the echo for a local model via Ollama (Gemma), and finally add a real tool (get_weather) so the program can fetch live weather instead of guessing. The point isn’t a fancy framework. It’s to see the loop: model proposes, your code runs tools, results go back into the transcript, model answers again. You'll Learn - Why a minimal read–decide–act loop is the skeleton of an agent - How Ollama fits in as a local model server and chat API - How to keep a message transcript (system / user / assistant) so context isn’t lost - Why tools matter: the model doesn’t fetch the web—your runtime does - How structured tool calls work: request → execute → tool message → second model call - How to separate responsibilities: Ollama vs model vs Node runtime vs tools --- 00:00 Introduction 01:18 About the channel 01:39 Step 1 — The smallest loop 04:46 Step 2 — Replace echo with a model call 10:33 Why tools matter 11:04 Step 3 — Add a real tool and the tool loop 18:57 Who does what 20:05 Recap — three steps 20:32 Takeaway and closing --- Final Takeaway An LLM alone is text in, text out. An agent is the orchestration loop that decides when to use tools and wires real actions to grounded answers. Once you see that loop in a small program, bigger agent setups are much easier to parse. 📘 MY BOOKS & COURSES 👉 Frontend System Design Essentials (Course): https://icodeit.thinkific.com/courses/frontend-system-design-essentials 👉 Frontend System Design Essentials (Book): https://leanpub.com/frontend-system-design-essentials/ 👉 React Anti-Patterns (Amazon): https://www.amazon.com/dp/1805123971 👉 More Tutorials on Advanced Patterns: https://icodeit.com.au/tutorials/advanced-network-patterns-react 📩 STAY CONNECTED 🧠 Newsletter (system design & clean code): https://juntao.substack.com 🌐 Website & Blog: https://icodeit.com.au 🐦 Twitter / X: http://twitter.com/JuntaoQiu 📺 YouTube (subscribe): https://www.youtube.com/@icodeit.juntao 💬 Question for You What’s the first non-demo tool you’d add after weather—calendar, search, your own API—and what would break in your loop if the tool failed or timed out? Hashtags #ai #systemdesign #agenticcoding #frontend #systemdesign