design-principles

design-principles is a skill for Claude Code from HermeticOrmus/LibreUIUX-Claude-Code. It costs 43 tokens per session (1,885 once invoked), scanned A, original, MIT.

A guide to the basic rules of visual communication, including how layout, color, type, and spacing affect what people notice and understand.

In plain words
What is it for?
Use it when making or reviewing interface and visual design decisions, teaching design basics, or finding the cause of a design problem.
Why use it?
It replaces guesswork with ways to explain why a design feels unclear or unbalanced. It helps evaluate visual choices against established principles.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the design-mastery plugin — 4 skills shipped together

Good fit Use it when making or reviewing interface and visual design decisions, teaching…

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/hermeticormus/libreuiux-claude-code/design-principles
Install

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.

Any agent
npx skills add HermeticOrmus/LibreUIUX-Claude-Code --skill design-principles
Clone the repo
git clone --depth 1 https://github.com/HermeticOrmus/LibreUIUX-Claude-Code

Made for: Claude Code.

Or install design-mastery, the plugin that ships this one along with the rest of its 4 skills.

Wrote 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.

agentmods badge for design-principles

README.md
[![agentmods](https://agentmods.dev/badge/skills/hermeticormus/libreuiux-claude-code/design-principles.svg)](https://agentmods.dev/skills/hermeticormus/libreuiux-claude-code/design-principles)
Your own site
<a href="https://agentmods.dev/skills/hermeticormus/libreuiux-claude-code/design-principles"><img src="https://agentmods.dev/badge/skills/hermeticormus/libreuiux-claude-code/design-principles.svg" alt="Measured on agentmods" height="20"></a>
Per session 43 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,885 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce 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

Measured 3d ago against content hash 4606f6cc24b8, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

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 3d 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.

Origin

Copies of this mod

1 near-identical copy found in the catalogue:

plugins/design-mastery/skills/design-principles/SKILL.md · 278 lines

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) or divide-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

Read the full file on GitHub · 278 lines

Files

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.

Changes

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.

  1. 3d ago First seen · 278 lines · 43 tokens per session scan A 4606f6cc24b8

Subscribe to this mod's changes

design-principles is a skill published in the GitHub repository HermeticOrmus/LibreUIUX-Claude-Code (101 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. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

Related

Other skills, from other repositories