1 The shift: Code is free now. Understanding isn't.

AI made writing code 10x easier and understanding code 10x harder, at the same time. The 10x easier part already happened. There’s a name for it: vibe coding. You describe what you want, let an AI build it, and ship it without reading every line. It sounds like a joke. It’s how a growing share of production software gets built. GitHub Copilot now generates nearly half of all code written by its users. The creator of Claude Code landed 259 PRs in 30 days, every line written by AI. Even Andrej Karpathy felt the ground shift so fast he went from 80% manual coding to 80% AI-assisted agent coding in a few months.

1.1 The problem: Comprehension debt is the silent killer

1.2 The reframe: From reading code to architectural thinking

1.2.1 The 90% skill is a commodity. The 10% is your muscle.

1.2.2 The 10% muscle: Use it or lose it

1.3 The multiplier: How to "work out" with AI

1.3.1 The coder gets code. The engineer gets stronger.

1.3.2 What an engineering rep looks like

1.4 "But AI hallucinates..."

1.4.1 Even the skeptics are using AI

1.4.2 How the engineer catches the bluff

1.5 The promise and the path

1.5.1 What you'll get from this book

1.5.2 How this book works

1.6 Summary