A design system declares a type scale: display is 64px at lg, heading-1 is 40px there, body text is 16px at 1.5. Six months later a pricing card title is 40px because somebody needed it to look right, and it is still marked up as heading-2. Nothing is broken, nothing warns, and the scale has quietly acquired a sixth size.
This walkthrough uses the tool's public README and checked-in example files. Run the command from a repository checkout with Node.js 22+.
Run the checked-in example
node bin/typography-scale-checker.mjs --root examplesRead the result
stdout carries the JSON report and nothing else, so it pipes straight into a parser. stderr carries the human summary and diagnostics.
Scope
Every bound is enforced and reachable from the command line. Exceeding one is an incomplete result with a finding naming the limit — never a silent truncation and never a pass.