A Design System Is a Promise, Not a Component Library

A button component with configurable props is a component. It becomes part of a design system only once teams across a project reach for it by default, instead of reaching for it once, hitting a limitation, and quietly rolling their own variant next to it.

That trust gets built or lost in the gaps — the prop that doesn't exist yet, the edge case the component wasn't designed for, the time it took to get a fix merged upstream. Every one of those moments is a decision point where a team either extends the shared system or forks around it, and forking around it is always faster in the moment.

Keeping a design system actually shared, over years and across teams, tends to come down to how fast the gaps get closed — not how complete the initial component set was.