# [You Don't Have a Design System](https://mattrothenberg.com/notes/you-dont-have-a-design-system/)

Published: Wed, Aug 26, 2026
Source: [mattrothenberg.com](https://mattrothenberg.com/notes/you-dont-have-a-design-system/)

> That is the difference. A component library gives builders reusable parts; a design system makes recurring decisions about structure, behavior, and user interaction canonical. When those decisions live only in a shipped screen or somebody’s head, agents expose the gap quickly: they build from what you encoded and make reasonable but different inferences everywhere else.