Agent Skill
Break UI skill
break-uiemilkowalski/skillsskills/break-ui/SKILL.md
Try to break a piece of UI by feeding it worst-case data — long names, unbreakable emails, one-letter names, missing fields, huge counts, zero items, long labels, non-Latin text, emoji, extreme numbers — then render it behind a "Demo data / Worst case" toggle and report everything that broke, with the fix for each. Use when the user asks to stress-test, break, or find edge cases in a component or screen, or to "try the worst case". For visual design critique use emil-design-eng; for motion use review-animations.
always on
122 tokname + description
once used
3,314 tokSKILL.md body
bundled files
18 KB
repo stars
48kGitHub
Install the Break UI skill
Skills CLI (Claude Code, Codex, Cursor and others)
npx skills add https://github.com/emilkowalski/skills --skill break-ui
Claude Code, by hand (all projects)
git clone --depth 1 https://github.com/emilkowalski/skills.git /tmp/skills mkdir -p ~/.claude/skills cp -R /tmp/skills/skills/break-ui ~/.claude/skills/break-ui
For one project only, copy the folder into .claude/skills/ in that project instead. The agent picks it up when a task matches its description.
What it costs your context
Agent Skills load in three steps. Tokens counted with the o200k tokenizer; your model's count will differ a little.
| When | What loads | Cost |
|---|---|---|
| Every session | Name and description | 122 tok |
| When the agent uses it | The SKILL.md instructions | 3,314 tok |
| Only if opened | 1 bundled files (8 KB) | varies |
Until it is used, break-ui costs about 11× less than the median MCP server we measured (1,362 tokens on every turn). Installing all 15 skills from emilkowalski/skills would load 1,400 tokens of descriptions. Skills vs MCP study
Checks
Our checks found nothing to flag: it follows the Agent Skills specification's naming and size guidelines and doesn't pipe downloads into a shell.
Checked 2026-10-22 · method
What's inside
The headings of its SKILL.md. Read the full file on GitHub.
- Breaking UI
- Initial Response
- Operating Posture
- Hard Rules
- Workflow
- Phase 1 — Map the surface
- Phase 2 — Build the worst case
- Phase 3 — Wire the toggle
- Phase 4 — Break it
- Phase 5 — Report and stop
- Phase 6 — Fix on request
- Required Output Format
- Part 1 — What broke
- Part 2 — Decisions for you
- Part 3 — What held up
- Invocation Variants
- Tone
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This skill encodes Emil Kowalski's philosophy on UI polish, component design, animation decisions, and the invisible details that make software feel great.
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Reverse-lookup glossary that turns a vague description of a web animation or motion effect into its exact term ("the bouncy thing when a popover opens" → Pop in; "the iOS rubber-band scroll" → Rubber-banding). Use when the user asks "what's it called when…", or describes a motion effect without knowing its name and wants the right word to prompt an AI or designer with. For naming an effect, not designing or building one.
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Survey a codebase's animation and motion code as a senior motion advisor, then produce a prioritized audit and self-contained implementation plans for other agents (or cheaper models) to execute. Read-only on source code — it plans improvements, it does not apply them. Use when the user asks to "improve the animations", "audit the motion", "make this app feel better", or wants a roadmap of animation fixes rather than a review of a single diff.
214k97 tok idle · 1,748 in use - find-animation-opportunitiesemilkowalski/skills
Search a codebase or UI for places that don't animate but should, and reject everything that shouldn't. Read-only; it proposes motion with exact values, it does not implement it. Use when the user asks "what could be animated here?" or wants to "make this feel more alive". For fixing existing animations, use improve-animations or review-animations instead.
199k78 tok idle · 2,206 in use - pick-ui-libraryemilkowalski/skills
Pick the right library for a given frontend task from a curated, opinionated list — numbers, OTP inputs, charts, command menus, virtualization, drag and drop, toasts, state, styling, and more. Only runs when explicitly invoked; it does not trigger on its own.
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Build multiple genuinely different versions of a UI piece you describe, rendered behind a visual picker so you can flip through them live and promote the one that feels right. Only runs when explicitly invoked; it does not trigger on its own.
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