Skip to content
Get packs

Guide · Agent skill

How to use the Color Contrast Checker agent skill

Updated · written with AI from the project's own documentation and checked against our catalogue data

The color-contrast skill gives an AI agent a checklist for WCAG minimum contrast rules, so it can review text and interface colors and tell you which ones fail. This guide explains what the skill does, how to install it from the ZIP on this page, how to ask for a review, and where its limits are. No prior experience with agent skills is needed.

Color Contrast Checkerthedaviddias/Front-End-Checklist · MIT

Quick start

  1. 1Download the ZIP. Get the color-contrast skill ZIP from this page and unzip it.
  2. 2Place the folder. Move the unzipped folder into ~/.claude/skills/ for personal use, or into a project's .claude/skills/ folder.
  3. 3Or upload it in the apps. In the Claude apps, go to Settings → Capabilities → Skills and upload the skill.
  4. 4Ask for a contrast review. Describe what to check in plain language, mentioning contrast, accessibility or WCAG, and paste the CSS or component code.
  5. 5Review the failures. Read which elements fail, the ratio the agent reports, and the suggested color changes.
  6. 6Verify with a checker. Confirm the exact ratios with WebAIM's contrast checker or the browser DevTools accessibility panel before release.

What the color-contrast skill makes the agent do

The skill covers the WCAG minimum contrast rules. Normal text needs a contrast ratio of at least 4.5:1. Large text (18pt or larger, or 14pt bold and larger) needs at least 3:1. Non-text parts such as icons, focus indicators and input borders also need at least 3:1 against the adjacent color.

When you ask the agent to review a page or component, the skill directs it to check these ratios, explain which elements fail, and suggest darker or lighter colors that pass. It also reminds the agent to check opacity-based lightening as a blended color, and that disabled controls and purely decorative elements are exempt.

  • Normal text: 4.5:1 (WCAG 2.1 SC 1.4.3, Level AA)
  • Large text: 3:1
  • Icons, focus indicators and input borders: 3:1 (WCAG 2.1 SC 1.4.11, Level AA)
  • AAA reference: 7:1 for normal text is mentioned briefly

Install the skill from the ZIP download

Download the ZIP for the color-contrast skill from this page and unzip it. The skill is a folder containing SKILL.md and references/rule.md.

For a personal install, place the unzipped folder in ~/.claude/skills/. For a single project, place it in that project's .claude/skills/ folder instead.

You can also upload the skill in the Claude apps under Settings → Capabilities → Skills.

  • Personal install: ~/.claude/skills/
  • Project install: the project's .claude/skills/ folder
  • Claude apps: Settings → Capabilities → Skills, then upload

Trigger the skill with a natural request

You do not need a special command. Describe the task in plain language and mention contrast, accessibility or WCAG. The skill's description tells the agent to apply it to visible text, text images, UI component borders, focus indicators and meaningful icons.

Include the thing you want checked. Pasting CSS, a component file or a list of color pairs gives the agent the most to work with.

  • "Check the text contrast in this stylesheet against WCAG AA."
  • "Does this button's border meet the 3:1 non-text contrast rule?"
  • "Review this login form for contrast problems and suggest passing colors."
  • "Can our brand blue #1a73e8 be used for body text on white?"

Read the results and apply fixes

Expect the agent to name the failing elements, state the ratio it found, and propose a fix. Per the skill's fix guidance, the usual approach is to darken the foreground or lighten or darken the background until the minimum is met.

Verify any number the agent gives you with a dedicated tool. The skill itself points to WebAIM's contrast checker and the browser DevTools accessibility panel for exact ratios.

  • For text failing 4.5:1, darken the text or lighten the background
  • For text failing 3:1 as large text, apply the same approach with the lower threshold
  • If you used opacity to lighten text, check the blended color instead

Know what the skill does not cover

The skill gives guidance from WCAG references. It is not a certified audit and does not replace human or specialist review for legal or compliance sign-off. It mainly targets AA. The files reviewed do not include a measurement script, so the agent describes the checks rather than measuring pixels automatically.

The skill has no listed requirements, does not run scripts, and does not use the network, according to the source reviewed.

  • Not a substitute for a certified accessibility audit
  • Targets WCAG AA by default; AAA is only briefly mentioned
  • No built-in pixel measurement script in the files reviewed

What people use it for

  • Quick accessibility pass on a page or component before release
  • Checking whether a brand palette meets WCAG AA for text and UI controls
  • Reviewing a form's input borders and focus indicators for 3:1 contrast
  • Preparing consistent contrast reasoning for an accessibility audit
  • Finding a darker or lighter shade of a grey that passes for body text

Frequently asked questions

Is the color-contrast skill free to use?

The source identifies the skill's license as MIT. The source does not list prices, so check the directory page for any other terms.

What do I need to run the color-contrast skill?

The source lists no requirements. It does not run scripts and does not use the network.

Where do I install an agent skill like this?

Unzip the downloaded folder into ~/.claude/skills/ for personal use or a project's .claude/skills/ folder. You can also upload it in the Claude apps under Settings → Capabilities → Skills.

What contrast ratio do I need for normal text?

Normal text needs at least 4.5:1 under WCAG 2.1 SC 1.4.3 Level AA. Large text, at 18pt or larger or 14pt bold and larger, needs at least 3:1.

Does this skill measure contrast automatically?

No measurement script is included in the files reviewed. The agent checks ratios by reasoning from the rules, so confirm exact values with WebAIM's contrast checker or browser DevTools.

How does this compare with a dedicated contrast checker tool?

The skill adds an AI review that explains failures and suggests fixes. Dedicated tools measure exact ratios from colors you enter, so the source recommends using both.

New agent skills, repos and AI tools — every week

The best new skills and open-source projects, the fastest-growing repos, and one free prompt. Five minutes to read. Unsubscribe anytime.

Our verdict

Use this skill if you are a front-end developer or designer who wants a fast WCAG AA contrast pass on pages, components or brand palettes, with explanations and fix suggestions. Pick a dedicated checker or a specialist audit if you need measured pixel values, AAA-level compliance by default, or formal compliance sign-off.

Download the skill