agentmods.dev

pixel-perfect

pixel-perfect is a skill for Claude Code from fubits1/svelte-skills. It costs 34 tokens per session (842 once invoked), scanned A, original, MIT.

A visual-checking workflow for CSS and HTML changes that records exact sizes, positions, and rendered styles before and after an edit.

In plain words
What is it for?
Use it when changing CSS, swapping HTML elements, or restructuring the page markup and you need to prove the rendered result stayed aligned.
Why use it?
It helps detect layout changes that screenshots alone may miss, including effects from browser defaults or global styles.

Skill for Claude Code

Written for Claude Code: user-invocable in frontmatter.

Part of the frontend plugin — 13 skills shipped together

not rated 10repo 12d ago A scan 34 tokens original MIT

Good fit Use it when changing CSS, swapping HTML elements, or restructuring the page markup and you need to prove the rendered result stayed aligned.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/fubits1/svelte-skills/pixel-perfect
View source ↗ fubits1/svelte-skills
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 fubits1/svelte-skills --skill pixel-perfect
Clone the repo
git clone --depth 1 https://github.com/fubits1/svelte-skills

Made for: Claude Code.

Or install frontend, the plugin that ships this one along with the rest of its 13 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 pixel-perfect

README.md
[![agentmods](https://agentmods.dev/badge/skills/fubits1/svelte-skills/pixel-perfect/github.svg)](https://agentmods.dev/skills/fubits1/svelte-skills/pixel-perfect)
Your own site
<a href="https://agentmods.dev/skills/fubits1/svelte-skills/pixel-perfect"><img src="https://agentmods.dev/badge/skills/fubits1/svelte-skills/pixel-perfect/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 pixel-perfect

Your own site · 80×15
<a href="https://agentmods.dev/skills/fubits1/svelte-skills/pixel-perfect"><img src="https://agentmods.dev/badge/skills/fubits1/svelte-skills/pixel-perfect.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 34 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 842 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 $0.00034 $0.00842
Opus 5.5 $0.00014 $0.00337
Sonnet 5.5 $0.00007 $0.00168
Haiku 4.5 $0.00003 $0.00084

Measured 2mo ago against content hash 1815f8679696, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

pixel-perfect 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.

plugins/frontend/skills/pixel-perfect/SKILL.md · 82 lines

How it starts

The opening of the file, as written. The whole thing — 82 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Pixel-Perfect: Mandatory Measurement Workflow

When making any CSS change or HTML element swap (e.g. <dl> to <ul>, <div> to <section>), follow this workflow exactly. Screenshots alone prove NOTHING about pixel parity, only measured numbers do.

Step 1: Measure BEFORE (while original code is still in place)

Use browser_evaluate to capture exact values for every affected element:

// Capture dimensions
el.getBoundingClientRect() // width, height, x, y

// Capture computed styles — the ACTUAL rendered values, not what CSS says
getComputedStyle(el).display     // may differ from your CSS (global overrides!)
getComputedStyle(el).gap
getComputedStyle(el).margin
getComputedStyle(el).padding
getComputedStyle(el).lineHeight
getComputedStyle(el).fontSize

Store these numbers. Report them. They are your baseline.

Critical: Measure ACTUAL computed styles, not what you think the CSS does

Global styles, resets, and browser defaults frequently override scoped CSS. A <dl> might render as display: grid; gap: 16px even though scoped CSS says display: flex; gap: 8px. Never assume, always measure.

Step 2: Make the code change

Edit the HTML/CSS.

Step 3: Measure AFTER

Navigate to the same page. Measure the same elements with browser_evaluate. Report the numbers side by side.

Beware HMR staleness

After git stash pop, git checkout, or file restoration, the dev server may serve stale CSS. Touch the file (touch path/to/file) and hard-reload before measuring.

Step 4: Compare and report

Report a table:

| Metric         | Before | After | Diff |
| -------------- | ------ | ----- | ---- |
| footer height  | 396px  | 396px | 0    |
| section height | 98px   | 98px  | 0    |

Step 5: Investigate any diff

If any measurement differs by even 1px:

  1. Do not dismiss it. Do not say "close enough" or "imperceptible."
  2. Investigate the root cause: default margins, line-heights, display mode, gap values, global style overrides.
  3. Fix it to 0px diff.
  4. Measure again to prove the fix.

Read the full file on GitHub · 82 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. 2mo ago First seen · 82 lines · 34 tokens per session scan A 1815f8679696

Subscribe to this mod's changes

pixel-perfect is a skill published in the GitHub repository fubits1/svelte-skills (10 stars, last pushed 12d ago), licensed MIT. It adds 34 tokens to every session and 842 once invoked, about $0.0001 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 2026-08-31.

CSS and stylingDesign and UXFrontend
Related

pixel-perfect compared with skills from other repositories

pixel-perfect next to 6 skills from other repositories
ModTypeStarsLast pushLicenceScanTokensWorks with
pixel-perfectfubits1/svelte-skillsSkill1012d agoMITA34Claude Code
anti-slop-designsickn33/agentic-awesome-skillsSkill49kyesterdayMITA34Claude Code
chakra-ui-builderchakra-ui/chakra-uiSkill41kyesterdayMITA214Claude Code, Codex
visual-ralphYeachan-Heo/oh-my-codexSkill34k4d agoMITA52Codex
frontend-ui-dark-tsmicrosoft/skillsSkill3.2kyesterdayMITA48Claude Code
open-design-setupcompozy/compozySkill2.8kyesterdayMITA67Claude Code, Codex
frontend-visual-qadaymade/claude-code-skillsSkill1.5kyesterdayMITA125Claude Code, Codex