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Design Token Inspector

Show which design token produced any value on screen, instead of guessing at computed CSS.

moderate Developer Experience

What it adds

A development-only inspector that reports, for a selected element, the tokens behind its colour, spacing, typography, radius, and shadow.

What your agent is told to do

5
  1. 1

    Find the app's existing token definitions and build the inspector on top of them, so the tool reports the same names the design system publishes rather than a second vocabulary invented for the tool.

  2. 2

    Let a developer point at any element and see, per property, the token name, its resolved value, and where it came from — the element itself, an ancestor, or the theme default.

  3. 3

    Resolve alias chains all the way down and display the whole path, so a surface colour that points at a semantic token that points at a palette primitive shows all three steps rather than only the last.

  4. 4

    Report honestly when a value has no token behind it. An unmatched raw value is the most useful thing the inspector can surface, and it must be labelled as unmatched rather than approximated to the nearest token.

  5. 5

    Do not ship the inspector to production users. Gate it behind a development build or an explicit internal flag, and confirm the code is absent from the production bundle rather than merely unreachable.

Edge cases it handles

7
  • Alias chains must be traced to their source token, and a circular or broken alias must be reported as broken rather than silently rendering the last value it happened to resolve to.
  • Inherited values and locally declared values must be visually distinguished — a developer chasing a wrong colour needs to know whether to edit this element or its ancestor.
  • The inspector must re-resolve when the active theme or breakpoint changes, because the same element can be driven by different tokens in light and dark, or at different widths.
  • Leaving the tool in the production bundle leaks the internal token vocabulary and adds weight for every user; verify its absence in a built artefact, not just in configuration.
  • Values produced by calculation or interpolation will not match any token exactly; show the expression and its inputs rather than claiming no token is involved.
  • The inspector's own panel must not appear in its own readings, and hovering it must not change what is being inspected.
  • Reporting which token is behind a value is this feature's job; deciding that an untokenised value is a defect and failing a check on it belongs to Design Token Linter — the inspector observes, the linter enforces.

Definition of done

8
  • Selecting any element reports the token behind each of its colour, spacing, typography, radius, and shadow values.
  • Alias chains are shown in full, from semantic name to source primitive.
  • Inherited values are labelled differently from locally declared ones.
  • Readings update correctly after a theme change and at every defined breakpoint.
  • Values with no matching token are labelled as unmatched rather than rounded to the nearest one.
  • The inspector is absent from production builds, verified against the built output.
  • The feature matches the existing design system.
  • No existing functionality is broken.

Related features

How it works

  1. 1

    Copy the link

    Grab the Markdown instruction URL for this feature.

  2. 2

    Give it to your AI

    Paste it into Claude Code, Cursor, v0, Lovable — whatever you build with.

  3. 3

    It inspects, then implements

    Your agent reads your existing app first, then adds the feature to fit it.

Works with your stack

These instructions are written to adapt. They tell the agent to detect your framework, match your existing design system, and reuse what you already have — rather than assuming a particular stack.

Need it tighter than that? Customize the feature and tell it exactly what you're running.