Foundations
What is Open-Closed Principle?
Design modules so you can add behavior without editing existing code. Extend through new types, not surgery on old ones.
In real work
Open-closed principle: we registered a new export handler instead of editing the core pipeline.
How is this different from Googling it?
Google gives a definition. Prompthaus pairs each term with how it shows up in standups, PRs, prompts, and design reviews—then quizzes you until the word sticks. One term a day on iPhone.