law-of-common-region

law-of-common-region is a skill for Claude Code from Owl-Listener/designer-skills. It costs 48 tokens per session (591 once invoked), scanned A, original, MIT.

A visual design guideline in which a shared background, border, card, or other container makes elements appear to be one group.

In plain words
What is it for?
Use it to structure cards, panels, sidebars, tab sections, and other contained interface groups.
Why use it?
It clarifies relationships when spacing alone is not strong enough, especially in dense layouts.

Skill for Claude Code

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

Part of the ui-design plugin — 19 skills, 5 commands shipped together

not rated 2.6krepo +89 7d ago A scan Socket: passSnyk: passSkillSpector: pass 48 tokens original MIT

Good fit Use it to structure cards, panels, sidebars, tab sections, and other contained interface groups.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/owl-listener/designer-skills/law-of-common-region
About the project

Owl-Listener/designer-skills is a collection of AI-agent skills, commands, and plugins for design work, covering research, design systems, interfaces, interaction, and delivery. Designers and developers use it inside coding assistants to guide design tasks, and the catalogue entries represent selected parts of that larger collection.

Owl-Listener/designer-skills · 2,619 stars · on GitHub

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 Owl-Listener/designer-skills --skill law-of-common-region
Clone the repo
git clone --depth 1 https://github.com/Owl-Listener/designer-skills

Made for: Claude Code.

Or install ui-design, the plugin that ships this one along with the rest of its 19 skills, 5 commands.

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 law-of-common-region

README.md
[![agentmods](https://agentmods.dev/badge/skills/owl-listener/designer-skills/law-of-common-region/github.svg)](https://agentmods.dev/skills/owl-listener/designer-skills/law-of-common-region)
Your own site
<a href="https://agentmods.dev/skills/owl-listener/designer-skills/law-of-common-region"><img src="https://agentmods.dev/badge/skills/owl-listener/designer-skills/law-of-common-region/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.

agentmods 80×15 button for law-of-common-region

Your own site · 80×15
<a href="https://agentmods.dev/skills/owl-listener/designer-skills/law-of-common-region"><img src="https://agentmods.dev/badge/skills/owl-listener/designer-skills/law-of-common-region.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 48 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 591 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. Third-party audits
  • Socket pass 6 May 2026
  • Snyk pass 6 May 2026
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 $0.00048 $0.00591
Opus 5 $0.00024 $0.00296
Sonnet 5 $0.00010 $0.00118
Haiku 4.5 $0.00005 $0.00059

Measured 9d ago against content hash ccd98110b770, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

law-of-common-region 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 9d 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.

ui-design/skills/law-of-common-region/SKILL.md · 42 lines

How it starts

The opening of the file, as written. The whole thing — 42 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Law of Common Region

You are an expert in Gestalt visual organization and containment-based grouping.

What You Do

You apply the Law of Common Region to create clear groupings using visual boundaries — backgrounds, borders, cards, and surfaces — so users understand which elements belong together.

The Principle

Elements enclosed within a shared boundary or placed on a shared background are perceived as a group, even when they are not especially close together. Containment is one of the strongest grouping signals available:

  • A card with a background creates an unambiguous group
  • A colored section background ties disparate content into a unit
  • A panel border tells users that everything inside belongs together

Common Region vs Proximity

Both signal grouping; they work differently:

Law of Proximity Law of Common Region
Mechanism Spatial closeness Shared boundary or background
Best for Related items already close Items that need a stronger or explicit boundary
Overhead Zero — just spacing Visual weight — a border or background is present
When to prefer Most layout grouping Cards, panels, sidebars, tabbed sections, modals
Use proximity first; add common region when proximity alone is insufficient or when the grouping boundary needs to be explicit (e.g. a card that can be acted on as a unit, a form section within a larger form).

Applications

Pattern Common Region Role
Cards Container clearly delimits a discrete item
Sidebar Background or border separates navigation from content
Modal / sheet Surface elevation signals an isolated task context
Form sections Background or rule divides logical groups within a long form
Table rows Hover/selection background shows a row as a unit
Tag groups Pill background makes each tag a discrete object
Tooltip Container boundary distinguishes overlay from page content

When Containment Is Counterproductive

  • Using cards for everything flattens hierarchy — not every group needs a container
  • Nested common regions create visual noise; limit nesting depth to two levels
  • A border for its own sake adds clutter; if proximity already communicates the grouping, the border is redundant

Read the full file on GitHub · 42 lines

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. 9d ago First seen · 42 lines · 48 tokens per session scan A ccd98110b770

Subscribe to this mod's changes

law-of-common-region is a skill published in the GitHub repository Owl-Listener/designer-skills (2,619 stars, last pushed 7d ago), licensed MIT. It adds 48 tokens to every session and 591 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

ui-review

Review UI code for StyleSeed design-system compliance, accessibility, mobile ergonomics, spacing discipline, and implementation quality.

LiHongwei-cn/lihongwei-cn · 26 tokens

design-system

Use this skill BEFORE writing or restyling ANY user-facing interface in WrongStack. It drives the Design Studio engine: commit to a kit, tune it (radius / density / font / motion), materialize the tokens into a real theme file, build against those tokens, then verify adherence. Trigger it whenever the user asks to…

WrongStack/WrongStack · 248 tokens

tailwind-shadcn

Tailwind CSS utility patterns with shadcn/ui component usage, theming via CSS variables, and responsive design. Use when styling components, installing shadcn components, implementing dark mode, or creating consistent design systems.

BlackBeltTechnology/pi-agent-dashboard · 50 tokens

anti-slop-frontend

A mechanical, countable anti-slop checklist for AI-generated frontend. Catches the specific signatures an undirected model defaults to: AI-purple glows, Inter-everywhere, em-dashes, div-based fake screenshots, eyebrow-on-every-section, beige+brass "premium" palettes, generic Jane Doe / Acme data. Advisory layer that…

BlackBeltTechnology/pi-agent-dashboard · 147 tokens

frontend-mockup-loop-dashboard

Dashboard-specific adapter on the generic frontend-mockup-loop skill: binds the 7-step design loop to pi-agent-dashboard component sources, theme-system tokens, and isolated verification. Use when designing/redesigning any pi-agent-dashboard client surface. Triggers: "design a dashboard screen", "mockup a dashboard…

BlackBeltTechnology/pi-agent-dashboard · 83 tokens

hue

Meta-skill that generates new design language skills. Works on Claude Code and Codex. Use when the user says 'create a design skill', 'generate design language', 'new design system skill', 'design skill inspired by X', 'design skill from this screenshot', '/hue', or 'use hue'. Also triggers for 'remix my design skill'…

dominikmartn/hue · 84 tokens