# Unused Token Detection

## Objective

Find the design tokens nothing references any more, before they harden into permanent debt.

A report of every theme and design token in the codebase alongside where, or whether, it is still referenced.

## Before You Begin

This feature is being added to an application that already exists and already
works. Do not scaffold a new project, and do not assume a blank slate.

Inspect the codebase first and establish:

- The existing application structure and where code of this kind already lives.
- The framework and version in use.
- The existing design system — colours, spacing, typography, and component conventions.
- Existing UI components you can reuse instead of writing new ones.
- The existing database structure, if this feature needs to persist anything.
- The existing authentication and authorization system, if this feature is user-scoped.
- Dependencies already installed, so you don't add a library that duplicates one.
- The existing test setup and conventions.

Only start writing code once you understand the above. If the application
already implements part of this feature, extend it rather than replacing it.

## Implementation Instructions

1. Find the files that define the app's tokens — colours, spacing, radii, type steps, shadows, motion durations — and treat that set as the authoritative list to check against.
2. Resolve every reference the codebase makes, in stylesheets, component source, inline styles, and any theme configuration, and record the count and the locations against each token.
3. Report three distinct outcomes rather than one: referenced, referenced only by other tokens, and referenced by nothing at all. The middle case is the one people delete by mistake.
4. Make the report a repeatable check that can be run on demand and read in a diff, not a one-off list pasted into an issue that is stale within a week.
5. Do not delete anything as part of this feature. Detection and removal are separate acts, and an automatic sweep that removes a token a customer theme still sets will break that theme silently.

## UI and UX Requirements

Match the application's existing design system exactly. Reuse its components,
spacing, and typography. This feature should look like it was always there.

## Responsive Requirements

Works on mobile, tablet, and desktop. Touch targets are large enough to hit on a
phone, and nothing overflows horizontally at 320px.

## Accessibility Requirements

- Fully keyboard navigable.
- Correct semantic elements and ARIA roles.
- Visible focus states.
- Meets WCAG AA contrast.
- Dynamic changes are announced to screen readers.
- Respects prefers-reduced-motion.

## Edge Cases

- Tokens assembled at runtime — a name built from a variant string, a colour picked by lookup from a data value — will look unused to any scan that only matches literal text. Detect the patterns that build names dynamically and mark everything they could reach as uncertain rather than unused.
- A token that is deliberately deprecated but still shipped for compatibility is not the same as a token nobody ever used. Carry the deprecation status through to the report so the two are never merged into a single number.
- Aliases must be traced to the end of the chain before any judgement is made. A base token referenced only by an alias that is itself referenced by a live component is in active use, and reporting it as dead is the most common way this check causes an outage.
- The scan must cover every theme, every brand, and every package in the repository. A token that is unused in the default theme and load-bearing in the dark or high-contrast one is used.
- Tokens consumed by consumers outside this repository — an embed, a published package, a documented customer theming surface — cannot be judged from this codebase alone and must be flagged as externally visible.
- Tokens referenced only by tests, stories, or documentation fixtures should be reported separately, since that is evidence of abandonment rather than of use.

## Testing

Exercise the feature end to end in the running application. Cover every edge case
above, then run the existing test suite and confirm nothing regressed.

## Acceptance Criteria

- [ ] Every token defined in the app appears in the report with its reference count and locations.
- [ ] Alias chains are resolved to their end before a token is classified.
- [ ] Deprecated, unused, and dynamically referenced tokens are three separate categories in the output.
- [ ] The scan covers all themes and all packages, not only the default theme.
- [ ] The check can be re-run on demand and produces a stable, diffable result.
- [ ] No token is removed by the feature itself.
- [ ] The feature matches the existing design system.
- [ ] No existing functionality is broken.

## Adaptation Rules

- Match the existing design system. Do not introduce a new colour palette,
  spacing scale, or component library.
- Reuse existing components and utilities wherever they fit.
- Follow the naming, file layout, and code style already present.
- Do not upgrade, replace, or remove existing dependencies to make this
  feature fit. Adapt the feature to the app, not the app to the feature.
- Do not break existing functionality. If a change is genuinely required in
  existing code, make the smallest one that works and say so.
- If something in these instructions conflicts with how the application is
  built, follow the application and explain the deviation.

## Final Verification

Before you report the work as done:

1. Re-read the acceptance criteria above and check each one against what you
   actually built.
2. Run the application and exercise the feature end to end.
3. Run the existing test suite and confirm you have broken nothing.
4. Check the feature on mobile, tablet, and desktop widths.
5. Check keyboard navigation and focus handling.
6. Summarize what changed: files added, files modified, and anything you
   deliberately did differently because of how this application is built.

If any acceptance criterion is unmet, fix it before reporting completion.