google-labs-code/design.md ? reverse-engineered prompt

I want to build a tool that helps me define a visual brand identity for an AI coding assistant to use. The core idea is to create a special markdown file format, let's call it DESIGN.md.

This file should have two parts. At the top, it should contain structured design tokens for things like specific color hex codes, typography details (font family, size, weight), and values for spacing and corner rounding. The second part, the body of the file, should be human-readable markdown prose. This is where I can explain the why behind the design, describing the overall vibe and providing guidance on how to use the different styles.

I also need a command-line utility built in TypeScript that can work with these files. It should be able to 'lint' a file to validate it, checking for broken references and even warning about accessibility issues like bad color contrast. I'd also like it to be able to 'diff' two files to see what design tokens have changed, and 'export' the tokens into other formats like a Tailwind theme.