Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add Pierry/harness-kit --skill designergit clone --depth 1 https://github.com/Pierry/harness-kitWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/pierry/harness-kit/designer)<a href="https://agentmods.dev/skills/pierry/harness-kit/designer"><img src="https://agentmods.dev/badge/skills/pierry/harness-kit/designer/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/pierry/harness-kit/designer"><img src="https://agentmods.dev/badge/skills/pierry/harness-kit/designer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00081 | $0.05612 |
| Opus 5.5 | $0.00032 | $0.02245 |
| Sonnet 5.5 | $0.00016 | $0.01122 |
| Haiku 4.5 | $0.00008 | $0.00561 |
Grade A, and why
designer scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 357 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Designer conventions. Apply when SSE builds something new with a UI (new app, page, feature,
landing). Layers on top of the area skill (web/mobile), does not replace it. Project override:
{repo}/.claude/conventions/web.md wins. Match existing design system if repo already has one; only
green-field gets these defaults.
READ FIRST: Material Design 3 is non-negotiable
Every visual surface this skill touches must be Material Design 3. Not "M3-inspired", not "close enough". M3 is the system: token-driven color roles, the shape scale, tonal elevation, state layers, and motion. If you are about to write a color, a border, a radius, or a callout, it comes from M3, not from instinct or a CMS habit. This rule has been broken before; do not break it again.
Before you ship any surface, self-check against these top offenders. Each one is a hard rule with its own section below; this is the unmissable summary, not the exception list.
- No colored left-border accent bars. A
border-left: 3px/4px solid var(--primary)on a card, hint, callout, banner, or "supporting" box is forbidden. It collides with the shape-scale radius and leaves a colored sliver in the rounded corner (the classic "corzinha no canto"). Color the surface with a tonal container (secondary-container/surface-container-high), never one edge. See "Info, help, and supporting surfaces". - Tonal containers, not ad-hoc borders, carry meaning. Reach for a
*-containerrole + itson-*text + a real shape radius + an MD3infoicon. A stripe is not a design system. - Tokens only, never raw hex in component CSS. Define roles once for light and dark.
- No emoji, ever. Use Material Symbols or a single modern open set. Draw brand marks original.
- No em-dashes or en-dashes anywhere: copy, headings, comments, commits, PRs, docs, all locales.
- Both themes, always. Light and dark, system-preference first, choice persisted.
- Vivid, on-trend color, never a timid grey wash. Saturated modern seed + a second accent + purposeful gradients. A washed-out palette is a build blocker. See "Vivid, on-trend color".
- A real, beautiful typeface, never the raw system stack. Load/embed a current variable face (Geist, Instrument Sans, Bricolage Grotesque, etc.); system-ui as the final look is forbidden.
- Depth and motion on every surface. Layered + tinted shadows, accent glow, highlights/glass,
and animation are always on (with
prefers-reduced-motion). Flat and shadowless is a defect.
When in doubt, open the matching section below and follow it literally. The detailed rules win over any quick instinct, and the "Forbidden" list at the end is exhaustive. Treat a violation of any of these as a build blocker, the same as a failing test.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 1mo ago First seen · 357 lines · 81 tokens per session scan A 709814b6df51
designer is a skill published in the GitHub repository Pierry/harness-kit (4 stars, last pushed 19d ago), licensed MIT. It adds 81 tokens to every session and 5,612 once invoked, about $0.0003 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
Other skills, from other repositories
frontend-enhancer
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generic-design-system
Complete design system reference for any project - colors, typography, spacing, components, animations. Adapts to project theme and tech stack. Use when implementing UI, choosing colors, creating animations, or ensuring brand consistency. For new design systems, use ui-research skill first.
generic-react-design-system
Complete design system reference for React applications. Covers colors, typography, spacing, component patterns, glassmorphism effects, GPU-accelerated animations, and WCAG AA accessibility. Use when implementing UI, choosing colors, applying spacing, creating components, or ensuring brand consistency.
generic-static-design-system
Complete design system reference for static HTML/CSS/JS sites. Covers colors, typography, component patterns, animations, and accessibility. Use when implementing UI, choosing colors, or ensuring brand consistency.
generic-static-ux-designer
Professional UI/UX design expertise for static HTML/CSS/JS sites. Covers design thinking, user psychology, visual hierarchy, minimalist interaction patterns, accessibility, and performance-driven design. Use when designing features, improving UX, or conducting design reviews.
agent-accessibility-expert
Specialist subagent: WCAG compliance, screen reader compatibility, and inclusive design patterns. Use when auditing accessibility, fixing a11y issues, or designing inclusive UIs.