Day 9: Real-World Agentic Systems

Welcome to Day 9 of Building Agentic AI Applications!

​Missed previous days’ posts? Find them here

So far, we’ve covered all the ingredients that make up an agent: tools, planning, RAG, memory, structure, and even coordination in multi-agent setups.

But you might be thinking:
“Where does all this actually show up in the real world?”

Let’s walk through a few public-facing systems that exhibit agentic behavior — as far as we can tell.

⚠️ A quick note:
These aren’t open source. We don’t know their exact internals. What follows is an informed simplification based on how they behave externally — just enough to understand how the agentic stack might show up in practice.