This is the short list I run through before a design goes to development. It saves a lot of back-and-forth later.
- Every state is designed. Empty, loading, error, success, disabled, and what happens with very long text.
- Components are linked, not detached. If it looks like the button, it should be the button.
- Spacing and colour use tokens. No one-off values that someone has to measure by hand.
- Accessibility is checked. Contrast, focus order, touch targets and alt text notes are in the file.
- The flow is annotated. Where each screen leads, what triggers it, and any logic that isn't obvious from the picture.
Then I walk a developer through it, because the best checklist still misses something a quick conversation catches.