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 HermeticOrmus/design-mastery-claude-code --skill design-principlesgit clone --depth 1 https://github.com/HermeticOrmus/design-mastery-claude-codeWrote 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/hermeticormus/design-mastery-claude-code/design-principles)<a href="https://agentmods.dev/skills/hermeticormus/design-mastery-claude-code/design-principles"><img src="https://agentmods.dev/badge/skills/hermeticormus/design-mastery-claude-code/design-principles.svg" alt="Measured on agentmods" 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 | $0.00043 | $0.01885 |
| Opus 5 | $0.00022 | $0.00942 |
| Sonnet 5 | $0.00009 | $0.00377 |
| Haiku 4.5 | $0.00004 | $0.00188 |
Grade A, and why
design-principles 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 8d 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.
This is a copy
100% identical to design-principles — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 278 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Design Principles
The fundamental laws governing visual perception and communication. These principles are not opinions—they're observations about how human vision and cognition work.
When to Use This Skill
- Making visual design decisions
- Evaluating whether a design "works"
- Explaining why something feels off
- Teaching design fundamentals
- Debugging design problems
Core Principles
1. Visual Hierarchy
The Law: Not all elements are equally important. Design must guide the eye.
Establishing Hierarchy:
| Tool | What It Does | Example |
|---|---|---|
| Scale | Larger = more important | Hero headlines vs. body text |
| Weight | Heavier = more important | Bold headings vs. light body |
| Color | Saturated/contrasting = attention | Primary CTA vs. secondary |
| Position | Top-left (in LTR) = first seen | Logo placement |
| Space | More space = more importance | Generous padding around CTAs |
| Depth | Shadows/elevation = prominence | Floating action buttons |
Testing Hierarchy: Blur the design at 50%. Can you still identify:
- The primary focal point?
- The secondary information?
- The action you should take?
2. Gestalt Principles
The Law: The brain organizes visual elements into meaningful groups.
Proximity
Elements near each other are perceived as related.
Good: [Label] [Label]
[Input] [Input]
(8px gap) (8px gap)
(32px gap between groups)
[Label] [Label]
[Input] [Input]
Bad: [Label] [Label] [Label] [Label]
[Input] [Input] [Input] [Input]
(equal spacing destroys grouping)
In Tailwind:
- Related items:
space-y-2(8px) - Unrelated groups:
space-y-8(32px) ordivide-y
Similarity
Elements that look alike appear grouped.
When multiple card types exist, make categories visually distinct:
- Same category: same border-radius, shadow, padding
- Different category: different color, icon style, or layout
What ships with it
3 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 8d ago First seen · 278 lines · 43 tokens per session scan A 4606f6cc24b8
design-principles is a skill published in the GitHub repository HermeticOrmus/design-mastery-claude-code (12 stars, last pushed 3mo ago), licensed MIT. It adds 43 tokens to every session and 1,885 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to design-principles, differing in 0 lines, and is treated as a copy.
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