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Handfish Design

A Claude Code plugin for the Handfish Design System. Handfish provides Web Components and OKLCH design tokens for Noisedeck, Tetra, and other Noise Factor products.

The plugin teaches light-DOM style injection, --hf-* token use, form-associated components, and the 17-theme system. It prevents common mistakes with hardcoded colors, !important, Shadow DOM workarounds, and event semantics.

What it does

• Loads handfish conventions on demand: Claude loads relevant references when you work on an app that imports handfish or uses --hf-*.
• Enforces token discipline: catches hardcoded colors, spacings, radii, and shadows. Rewrites them to design tokens.
• Knows the component catalog: 21 custom elements, the AboutDialog class, and the toast, tooltip, escape, and keyboard-shortcut utilities. The references cover tag names, events, attributes, and form-association behavior. Tests check the catalog against handfish. See "Staying current" below.
• Guides theme switching: 17 theme stylesheets covering 20 data-theme values (some files declare both dark/light variants), plus the two default modes. The skill knows how each one re-skins the token layer.
• Models the styling layer correctly: handfish injects styles into the document head — components participate in the global cascade. The skill teaches override-by-specificity instead of !important or Shadow DOM hacks.
• Bridges color spaces: directs Claude to existing utilities for RGB / HSV / OkLab / OKLCH / hex conversion.
• Walks contributors through adding a new component: directory layout, style injection pattern, exports, examples page, visual regression baselines.

Install

/plugin marketplace add noisefactorllc/handfish-design
/plugin install handfish-design@noisefactor

Or require it for your team by adding to .claude/settings.json:

{
  "extraKnownMarketplaces": {
    "noisefactor": {
      "source": {
        "source": "github",
        "repo": "noisefactorllc/handfish-design"
      }
    }
  },
  "enabledPlugins": {
    "handfish-design@noisefactor": true
  }
}

When it activates

The skill triggers whenever Claude is doing web work that touches:

• Imports from handfish or @noisedeck/handfish
• --hf-* CSS variables in stylesheets or inline styles
• Any handfish custom element: <toggle-switch>, <slider-value>, <select-dropdown>, <dropdown-menu>, <dropdown-item>, <color-picker>, <color-wheel>, <color-swatch>, <gradient-stops>, <vector2d-picker>, or <vector3d-picker>. This also includes <justify-button-group>, <code-editor>, <image-magnifier>, <knob-dial>, <led-matrix>, <tempo-bar>, <menu-bar>, <seance-dialog>, <session-status>, and <join-session-dialog>.
• The AboutDialog JS class (constructed with new AboutDialog({...}), then .show())
• Toast helpers (showToast, showSuccess, showError, showWarning, showInfo)
• Tooltip initialization (initializeTooltips, class="tooltip" + data-title attribute)
• The escape stack (registerEscapeable, unregisterEscapeable, initEscapeHandler)
• Keyboard-shortcut formatting (formatShortcut, isMacPlatform)
• Color conversion utilities (rgbToHex, parseHex, rgbToHsv, OkLab/OKLCH math)
• Right-to-left / bidi work: dir="rtl" on a handfish page, data-language="industrial", or overriding a component's built-in strings
• Frontend code in any Noisemaker-based app (Noisedeck, Tetra, Foundry, Polymorphic, Layers, Shade, Blaster, ShuffleSet, Sleeve, Remap, Handfish itself)

Reference docs

The plugin includes domain-specific reference documents that Claude loads contextually:

Reference	Covers
setup.md	CDN URLs, importmap pattern, three pinning levels (/0, /0.10, /0.10.1), font preloading, base styles, the industrial.css typeface opt-in, RTL setup
tokens.md	The full --hf-* token catalog, OKLCH color format, semantic vs. primitive tokens, the --hf-led-* readout palette, why hardcoding breaks themes
theming.md	The 17 built-in themes, data-theme switching, building a custom theme, dark/light variants, preventing FOUC, and the theme / language / direction axes
components.md	Hand-written prose for the 21 custom elements + AboutDialog class + helper utility families: usage patterns, examples, gotchas, anti-patterns
api-canonical.md	Machine-generated source-of-truth reference — attribute names, event types, event detail payloads, form-association status, toast defaults. Generated deterministically from handfish source, checked by npm run check. Wins when it disagrees with components.md.
styling.md	Light-DOM style injection model, overriding component styles by specificity, logical vs. physical CSS for RTL, why !important and Shadow DOM workarounds are banned
i18n.md	Bidi/RTL support, dir, overridable strings, logical CSS, and <bdi> isolation. Handfish provides component support. Apps provide translations.
color.md	Color conversion utilities (rgbToHex, parseHex, OkLab/OKLCH math), the 0–255 vs OKLCH conventions
utilities.md	Toasts (defaults, real options, dismissLabel), the stack-based escape handler, tooltip initialization (class="tooltip" + data-title), platform-aware shortcut formatting (formatShortcut)
contributing.md	Adding a new component to handfish itself + the canonical-reference regeneration workflow for skill maintainers

Staying current

The last API audit was 2026-08-12, against handfish 0.10 at HEAD commit 9bbb287. It covered all industrial components (knob-dial, led-matrix, tempo-bar), menu-bar, and the Seance components (seance-dialog, session-status, join-session-dialog). It also covered code-editor collaboration APIs, bidi/RTL support, and shortcuts utilities. The generated references/api-canonical.md records separate provenance. Its JSON last changed at commit d8d350c on 2026-07-28, when the extracted API last changed.

handfish ships components independently of this repo. This repo does not update automatically when handfish ships, so the plugin can teach Claude a catalog missing a third of the library. Checks cover both surfaces that can drift:

• references/api-canonical.md — generated from handfish's machine-extracted docs/component-api.json.
• The description frontmatter in skills/handfish-design/SKILL.md — the activation trigger. A tag missing here means nobody working on that component gets handfish guidance at all.

npm test          # both drift checks, plus the generator's own behaviour
npm run check     # is api-canonical.md current? (read-only, exits non-zero if not)
npm run regenerate

The drift checks need a sibling handfish checkout at ../handfish. Without one, they skip, so the suite still runs standalone. The CI test job gates changes to this repo with the drift checks skipped. Thus, a handfish release cannot fail an unrelated PR. A separate weekly drift job clones handfish and runs the checks live.

The generator produces byte-identical output for the same input. Provenance comes from git rather than a wall clock. An empty diff therefore means nothing changed, which makes the check possible.

When handfish ships something new:

1. cd ../handfish && git pull && node scripts/generate-component-api.js
2. Run npm run regenerate here. Review the diff.
3. Add any new tags to the description in SKILL.md (npm test names the missing ones).
4. Update prose in components.md for anything whose API changed.

See skills/handfish-design/references/contributing.md § "Maintaining this skill" for the full workflow.

License

MIT