Every few months a new AI term drops and everyone scrambles to sound smart about it. Context engineering. RAG. Agent memory. MCP.
Tal Raviv and Aman Khan, writing for Lenny’s Newsletter, built an interactive piece that has you learn these concepts by doing them inside Cursor. It’s part article, part hands-on tutorial. But the best parts are when they strip the terms down to what they actually are:
Let that sink in: memory is just a text file prepended to every conversation. There’s no magic here.
That’s it. Agent memory, the thing that sounds like science fiction, is a text file that gets pasted at the top of every chat. Once you know that, you can design for it. You can think about what belongs in that file and what doesn’t, what’s worth the context window space and what’s noise.
They do the same with RAG:
RAG is a fancy term for “Before I start talking, I gotta go look everything up and read it first.” Despite the technical name, you’ve been doing it your whole life. Before answering a hard question, you look things up. Agents do the same.
Tool calling gets the same treatment. The agent reads a file, decides what to change, and uses a tool to make the edit. As Raviv and Khan point out, you’ve done search-and-replace in Word a hundred times.
Their conclusion ties it together:
Cursor is just an AI product like any other, composed of text, tools, and results flowing back into more text—except Cursor runs locally on our computer, so we can watch it work and learn. Once we were able to break down any AI product into these same building blocks, our AI product sense came naturally.
This matters for designers. You can’t design well for systems you don’t understand, and you can’t understand systems buried under layers of jargon. The moment someone tells you “memory is just a text file,” you can start asking the right design questions: what goes in it? Who controls it? How does the user know it’s working?
The whole piece is a step-by-step tutorial for PMs, but the underlying lesson is universal. Strip the mystique, see the mechanics, design for what’s actually there.
