Use it to build a responsive testing matrix and verify breakpoints, readable fonts, usable touch controls, and pages that fit within the screen.

It helps find layouts that are hard to use on particular devices before users encounter them.

How dev-lou/PixelPilot configures GitHub Copilot

Q: What is PixelPilot uiux-responsive-tester.instructions.md?

A checklist for checking how a website behaves at different screen sizes, from small phones to large monitors. It includes touch targets, text scaling, and horizontal overflow checks.

Reuse

Borrowing it

Nothing to install: this file belongs to dev-lou/PixelPilot. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/dev-lou/PixelPilot/main/vscode/.github/instructions/uiux-responsive-tester.instructions.md

Clone the repo

git clone --depth 1 https://github.com/dev-lou/PixelPilot

Made for: GitHub Copilot.

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.

README.md

[![agentmods](https://agentmods.dev/badge/instructions/dev-lou/pixelpilot/uiux-responsive-tester/github.svg)](https://agentmods.dev/instructions/dev-lou/pixelpilot/uiux-responsive-tester)

Your own site

<a href="https://agentmods.dev/instructions/dev-lou/pixelpilot/uiux-responsive-tester"><img src="https://agentmods.dev/badge/instructions/dev-lou/pixelpilot/uiux-responsive-tester/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.

Your own site · 80×15

<a href="https://agentmods.dev/instructions/dev-lou/pixelpilot/uiux-responsive-tester"><img src="https://agentmods.dev/badge/instructions/dev-lou/pixelpilot/uiux-responsive-tester.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 2,866 This file is loaded in full into every session.

When invoked 2,866 The same file — it is already loaded in full.

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.

Model	Per session	Once invoked
Fable 5.1	$0.02866	$0.02866
Opus 5.5	$0.01146	$0.01146
Sonnet 5.5	$0.00573	$0.00573
Haiku 4.5	$0.00287	$0.00287

Measured 2mo ago against content hash e55f0d182226, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

PixelPilot uiux-responsive-tester.instructions.md 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 2mo 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.

vscode/.github/instructions/uiux-responsive-tester.instructions.md · 465 lines

How it starts

The opening of the file, as written. The whole thing — 465 lines — stays where its author put it; the contents beside it link to each section on GitHub.

UI/UX Responsive Testing Skill

Systematic responsive design verification across viewports. Ensures touch targets, overflow handling, and font scaling.

OVERVIEW

This skill generates comprehensive responsive testing checklists covering:

Viewport breakpoint testing
Touch target size verification (≥44px)
Horizontal overflow detection
Font scaling and readability
Device-specific considerations

STANDARD VIEWPORTS

Primary Test Breakpoints

Name	Width	Device Example	Priority
Mobile S	320px	iPhone SE	🟡
Mobile M	375px	iPhone 12/13	🔴
Mobile L	390px	iPhone 14/15	🔴
Mobile XL	428px	iPhone 14 Plus	🟡
Tablet	768px	iPad Mini	🔴
Tablet L	1024px	iPad Pro 11"	🟡
Desktop	1280px	Laptop	🔴
Desktop L	1440px	Desktop	🟡
Desktop XL	1920px	Large monitor	🟡

Breakpoint Tokens

:root {
  --breakpoint-sm: 640px;
  --breakpoint-md: 768px;
  --breakpoint-lg: 1024px;
  --breakpoint-xl: 1280px;
}

/* Usage */
@media (min-width: 768px) { /* md and up */ }
@media (min-width: 1024px) { /* lg and up */ }

TESTING MATRIX TEMPLATE

Page: [Page Name]

Viewport	Layout OK	Touch Targets	No Overflow	Font Readable
390px	✅ / ❌	✅ / ❌	✅ / ❌	✅ / ❌
768px	✅ / ❌	✅ / ❌	✅ / ❌	✅ / ❌
1280px	✅ / ❌	✅ / ❌	✅ / ❌	✅ / ❌

TOUCH TARGET REQUIREMENTS

Minimum Sizes

Element	Minimum Size	WCAG Level
Interactive elements	44×44px	AAA (recommended)
Links in text	24×24px	AA (minimum)
Dense UI (technical)	32×32px	Context-dependent

CSS Implementation

/* Base interactive element */
.btn,
.link,
.clickable {
  min-height: 44px;
  min-width: 44px;
  padding: var(--space-3) var(--space-4); /* 12px 16px */
}

/* Touch-friendly spacing for links */
.nav-link {
  padding: var(--space-3);
  margin: calc(var(--space-1) * -1); /* Negative margin to maintain visual spacing */
}

/* Icon buttons */
.btn--icon {
  width: 44px;
  height: 44px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

/* Form inputs */
input,
select,
textarea {
  min-height: 44px;
  padding: var(--space-3);
}

Read the full file on GitHub · 465 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.

2mo ago First seen · 465 lines · 2,866 tokens per session scan A e55f0d182226

Subscribe to this mod's changes

PixelPilot uiux-responsive-tester.instructions.md is an instructions file published in the GitHub repository dev-lou/PixelPilot (2 stars, last pushed 7mo ago), licensed MIT. It adds 2,866 tokens to every session, about $0.0115 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 2026-09-03.

CSS and styling E2E testing Frontend Testing ai-prompts copilot cursor-rules design-system developer-tools

PixelPilot uiux-responsive-tester.instructions.md next to 6 instructions from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
PixelPilot uiux-responsive-tester.instructions.mddev-lou/PixelPilot	Instructions file	2	7mo ago	MIT	A	2,866	GitHub Copilot
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vscode copilot-instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	3,093	GitHub Copilot
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PixelPilot: Instructions file for GitHub Copilot