How AI Agents Actually Work: A Practical Walkthrough from Building One | Towards AI

Author(s): Himanshu Sharma

Originally published on Towards AI.

For a long time, the word “AI agent” felt like a buzzword to me. Every other LinkedIn post was about agents. Every newsletter mentioned them. But when I tried to read the actual technical material, things got slippery very quickly. ReAct, tools, observations, system prompts, function calling — the terms kept piling up, and nothing was clicking.

So I did what usually works for me when I am stuck. I picked one small project and built it end to end.

I built TravelMind, a small AI agent that helps users plan trips. You ask it to plan a 5-day trip to Tokyo, and it actually does the work — searches the web for tips, checks the current weather, calculates a realistic budget, and gives you a day-by-day itinerary.