A11y Colours
Give it one colour and get a full, accessible palette back: 50–950 ramps for nine hues and two greys, lined up so every colour in a column has the same lightness and the same contrast.
That gives you one rule for the whole palette — how many steps apart two colours must be to pass 4.5:1 for text and 3:1 for icons. Export as CSS, JSON, or a design.md of light and dark mode rules for your AI builder.