responsive-checker

responsive-checker is a skill for Claude Code, Codex from codebygarv/Ai-skills. It costs 41 tokens per session (517 once invoked), scanned A, original, MIT.

A review guide for checking whether an interface adapts correctly to mobile, tablet, and desktop screen sizes. It looks at resizing, content overflow, touch targets, and how layouts rearrange at different widths.

In plain words
What is it for?
Use it before shipping responsive interfaces or when debugging a page that looks broken on a phone or tablet.
Why use it?
It finds layout problems that may be hidden when a page is tested at only one screen size.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/codebygarv/ai-skills/responsive-checker
Any agent
npx skills add codebygarv/Ai-skills --skill responsive-checker
Clone the repo
git clone --depth 1 https://github.com/codebygarv/Ai-skills

Made for: Claude Code, Codex.

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 responsive-checker

README.md
[![agentmods](https://agentmods.dev/badge/skills/codebygarv/ai-skills/responsive-checker.svg)](https://agentmods.dev/skills/codebygarv/ai-skills/responsive-checker)
Your own site
<a href="https://agentmods.dev/skills/codebygarv/ai-skills/responsive-checker"><img src="https://agentmods.dev/badge/skills/codebygarv/ai-skills/responsive-checker.svg" alt="Measured on agentmods" height="20"></a>
Per session 41 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 517 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00041 $0.00517
Opus 5 $0.00020 $0.00259
Sonnet 5 $0.00008 $0.00103
Haiku 4.5 $0.00004 $0.00052

Measured yesterday against content hash 49c5b077368f, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

responsive-checker 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 yesterday.

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.

skills/ui-ux/responsive-checker/SKILL.md · 36 lines

How it starts

The opening of the file, as written. The whole thing — 36 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Purpose

Determine whether a UI implementation will actually hold up across mobile, tablet, and desktop viewports — not just at whatever single width it was built and eyeballed at.

When to Use

  • Reviewing layout code (CSS/Tailwind/styled-components/etc.) meant to be responsive.
  • Before shipping any UI intended to be used on multiple device classes.
  • Debugging a specific "looks broken on mobile/tablet" report.

What to Analyze

  1. Breakpoint coverage — are there defined behaviors at common breakpoints (mobile ~375–428px, tablet ~768–1024px, desktop 1280px+), or does the layout only really work at one width?
  2. Fixed vs. fluid sizing — hardcoded pixel widths/heights that won't adapt, versus relative units (%, fr, rem, vw/vh used appropriately) that do.
  3. Overflow handling — content that will overflow, get clipped, or force horizontal scroll at narrow widths (long text, wide tables, fixed-width images).
  4. Touch target sizing — interactive elements meeting a reasonable minimum touch target size (~44x44px) on mobile, not just sized for mouse precision.
  5. Layout reflow — does a multi-column desktop layout collapse sensibly on mobile (stacking, hiding secondary content, or reflowing), or does it just shrink until unreadable?
  6. Text scaling — font sizes and line lengths that stay readable at mobile widths, not desktop-sized text crammed into a narrow viewport.

Output Format

  • Findings organized by viewport class (Mobile / Tablet / Desktop) where the issue manifests, or "All viewports" if it's breakpoint-independent.
  • Each finding: what breaks, at roughly what width, and the fix (a specific CSS/layout change).
  • If reviewing code without a live render, note explicitly which findings are code-inferred vs. would benefit from an actual visual check at that width.

Avoid

  • Assuming a specific breakpoint strategy the codebase doesn't use — check existing breakpoint conventions first and match them.
  • Flagging a deliberately mobile-hidden or desktop-only element as broken when it's an intentional responsive choice.
  • Recommending a full layout rewrite when a targeted breakpoint fix solves the actual issue.

Read the full file on GitHub · 36 lines

Files

What ships with it

2 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. yesterday First seen · 36 lines · 41 tokens per session scan A 49c5b077368f

Subscribe to this mod's changes

responsive-checker is a skill published in the GitHub repository codebygarv/Ai-skills (25 stars, last pushed 16d ago), licensed MIT. It adds 41 tokens to every session and 517 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.

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