What an FDE Actually Is

This part has five chapters, and together they answer one question: what, exactly, is this role that just exploded onto the scene.

What it is (Chapter 1, setting the title aside to look at the responsibility structure); which roles it resembles, and which it doesn't (Chapter 2, three testable behavioral tests); whether it's just outsourcing in a new coat, or a passing trend (Chapter 3, pulling the hype apart from what's real); why it exploded specifically in 2026 (Chapter 4, a verifiable timeline, not a mood); and whether AI will replace it (Chapter 5, which tasks are being eaten, and which layer isn't).

The five chapters form a single chain of questions: Define → Distinguish → Interrogate → Time It → Ask the Hardest Question. Each chapter creates the problem the next one has to solve. Chapter 1 sets up the definition of a "responsibility structure." Chapter 2 immediately uses it to cut adjacent roles apart. Chapter 3 lets the skeptics test whether this definition is old wine in a new bottle. Chapter 4 asks why, if it isn't hype, it exploded specifically now. Chapter 5 asks the sharpest question of all: what if AI eats it?

This part is written primarily for anyone who wants to see clearly what FDE actually means: engineers about to enter the field, managers writing or reading a job description, and anyone who's turned skeptical after being bombarded with the term. Engineering detail isn't covered here — that's Part Three's job. How the money works isn't covered here either — that's Part Five's job. This part does exactly one thing: turn the three letters "FDE" into something you can pick up and test for yourself.