Platform design skills (ehmo) review: verdict, safety and alternatives

Platform Design Skills is ehmo's bundle of eight Agent Skills for Apple HIG, Material Design 3 and WCAG 2.2. We rate it Conditional, 63/100, because it predates Liquid Glass. The safety grade is A, and the core numbers match Apple and Google.

Get the skill: platform-design-skills repository on GitHub · macOS SKILL.md at the reviewed commit · skills.sh listing

What are ehmo's platform design skills?

Ehmo's platform design skills are eight MIT-licensed Agent Skills for coding agents. They turn Apple HIG for six platforms, Material Design 3 and WCAG 2.2 into numbered rules. Each skill adds code examples and a review checklist.

An Agent Skill is a folder with a SKILL.md file that an agent loads when a task matches it. Our page on how Agent Skills work covers the format. Ehmo ships one such folder per platform. Apple's Human Interface Guidelines (HIG) set the rules for iOS, iPadOS, macOS, watchOS, tvOS and visionOS. Google's Material Design 3 sets the Android rules. WCAG 2.2, the W3C accessibility standard, anchors the web skill.

Installs on skills.sh, the directory behind the npx skills installer, totalled 12.6K at review. Eight SKILL.md files run from 17 to 39 KB each, about 237 KB in all. The README says 450+ rules since v1.1.0, while agenticskills.io still shows 300+. The CHANGELOG says v1.1.1, and SKILL.md metadata says 1.0.0.

Are Platform Design Skills worth installing?

Yes, but only for baseline reviews. Platform Design Skills scores 63/100, Conditional, at Moderate confidence. Core numbers such as 44pt iOS targets check out, but Liquid Glass and Material 3 Expressive are missing.

The worst failure is an agent that confidently enforces superseded rules as official guidance. We weighted the score toward that failure. Safety and setup score high, but missing Liquid Glass and M3 Expressive coverage pulls the result into Conditional.

Our notes on how the 63 was scored explain the weights.

Tessl, which runs a skill registry, scored structure in PR #1, not output quality. Our ranking of design skills ranked by verdict places this bundle against the other design verdicts.

How many tokens do Platform Design Skills use?

Each of the Platform Design Skills loads whole, at about 4,000 to 10,000 tokens; the macOS file measures 9,430. Our estimate for a typical one-screen HIG review is 14,000 input and 2,000 output tokens.

Our task estimate and our cost estimate differ. Five macOS reviews a week load about 47,150 skill tokens.

What changed since our review?

Nothing changed in Platform Design Skills since our 2026-09-30 review. The repository's last commit is still dated March 2026. The Liquid Glass gap stands, and the verdict stays Conditional, 63.

• 2026-10-21: GitHub compare shows commit dc2be82 identical to HEAD, with zero commits ahead.
• 2026-10-21: stars rose from 603 to 617. Open PR #2 deletes files and stays unmerged.

Are Platform Design Skills safe to install?

Yes, Platform Design Skills are safe to install, with safety grade A. The bundle holds Markdown skills, metadata files and rule indexes only. It has no scripts, hooks, network calls or credentials.

The grade comes from a static read of all 39 files at commit dc2be82. The main findings:

• Files: 8 SKILL.md, 8 AGENTS.md, 8 metadata.json and 8 rule indexes.
• Executables: none, and nothing carries the executable bit.
• PDF: a 2.4 MB Apple_HIG.pdf sits at the root, unused by any skill.
• Network and secrets: no network access, environment variables or credentials.
• Prompt injection: no surface, because the skills fetch no remote content.

On skills.sh, the macOS and iOS skills pass Gen Agent Trust Hub, Socket and Snyk audits. Our guide to vetting a skill before install lists the same checks for any skill.

What does the community report about Platform Design Skills?

The community reports on Platform Design Skills are file-level, not measured. Tessl's PR #1 scored structure at 70-89%. Our line checks confirm correct core numbers beside outdated iPadOS, Android and WCAG rules.

The table lists all 11 evidence items, six of them strong.

What are Platform Design Skills' known failures?

Platform Design Skills has four known failures at commit dc2be82. It lacks Liquid Glass and keeps replaced iPadOS Split View ratios. It prescribes a deprecated Android drawer and misstates two WCAG criteria.

The worst case is an agent redesigning an iPad app around removed Split View ratios. These problems sit in the files at the pinned commit:

1. No Liquid Glass. Liquid Glass is Apple's design language for iOS 26 and macOS 26. The newest API cited is iOS 17 (ios/SKILL.md#L19).
2. Replaced iPadOS windowing. The skill mandates 1/3, 1/2 and 2/3 Split View and Slide Over (ipados/SKILL.md#L74). iPadOS 26 windowing replaced them.
3. Deprecated Android drawer. The skill prescribes a permanent navigation drawer (android/SKILL.md#L192). Material 3 Expressive deprecated it.
4. Misstated WCAG criteria. The web skill treats SC 2.4.13 Focus Appearance, an AAA rule, as a WCAG 2.2 requirement. It misreads SC 2.5.8 target spacing as 24px (web/SKILL.md#L128).

The tvOS 250x150pt card minimum and the iOS 8pt grid have no HIG source. Some examples use .tabItem, a pre-iOS 18 pattern.

Which agents do Platform Design Skills work with?

Platform Design Skills has no verified agent. The publisher claims Claude Code and any agent that installs through npx skills. Its web skill shares the name web-design-guidelines with Vercel's skill.

Verified means public evidence shows the skill loading and working in that agent. Claimed means the publisher or a directory lists the agent.

Both ehmo's web skill and Vercel's skill use the frontmatter name web-design-guidelines. The two can collide when both sit in one agent. Our Vercel's Web Design Guidelines review covers the other skill.

How do you install Platform Design Skills?

Install Platform Design Skills with npx skills add ehmo/platform-design-skills, then keep the platforms you need. Add --skill ios-design-guidelines to install one platform skill alone. The bundle needs no dependencies or configuration.

1. Run the full install:

npx skills add ehmo/platform-design-skills

1. Install one platform instead, using its skills.sh name:

npx skills add ehmo/platform-design-skills --skill ios-design-guidelines

1. Clone the repository by hand, then copy one skills/<platform> folder into your agent's skills directory:

git clone https://github.com/ehmo/platform-design-skills.git

1. Skip the web skill when Vercel's web-design-guidelines is already installed.

Our guide to installing skills in Claude Code covers folder and plugin paths.

How do you use Platform Design Skills?

Use Platform Design Skills by asking the agent to review one SwiftUI, Compose or web screen. The agent applies the matching checklist. Name the target OS version, because the rules predate iOS 26.

Three example tasks fit the bundle well:

• Review a SwiftUI or UIKit iPhone screen for targets, Dynamic Type and navigation.
• Audit a Mac app's menu bar, toolbar, windows and keyboard shortcuts.
• Check a Compose screen against Material 3 colour roles, type scale and navigation.

The first two are the primary jobs. The Compose check is secondary.

Test it yourself:

• Load the iPadOS and iOS skills in your agent.
• Ask it to review a SwiftUI iPad app that targets iOS 26.
• See whether it demands Split View ratios.
• See whether it flags Liquid Glass tab bars as violations.

Is Platform Design Skills a good Claude skill for Apple design?

Yes for Apple design basics, no for current Apple design. Platform Design Skills covers six Apple platforms, and its 44pt, 11pt, 60pt and 29pt values match Apple. Liquid Glass and iPadOS 26 windowing are absent.

Pair the macOS skill with a current Liquid Glass source for macOS 26 work.

Do Platform Design Skills cover Material Design 3 for Android?

Yes, Platform Design Skills covers Material Design 3 baselines for Android. Its 48dp targets and M3 type scale match Google. It still prescribes a permanent navigation drawer and omits M3 Expressive components.

Material 3 Expressive is Google's 2025 update to Material Design 3. The android skill checks these values:

• 48dp minimum touch targets, matching Google.
• bodyLarge at 16sp, matching the M3 type scale.
• titleLarge at 22sp, matching the M3 type scale.
• Permanent navigation drawer, deprecated in M3 Expressive per 9to5google (2025-05).

Expressive components such as the expanded nav rail, docked toolbar and flexible nav bar are missing.

Where are Platform Design Skills on GitHub?

Platform Design Skills lives on GitHub at ehmo/platform-design-skills, under MIT. We reviewed commit dc2be82, which holds 39 files and an unused Apple HIG PDF. No commits have landed since March 2026.

• Repository: github.com/ehmo/platform-design-skills, MIT license, created 2026-02-01.
• Reviewed commit: dc2be825d8b439caea78e9eaa8fb3ac23b0ff3e9, dated 2026-03-18.
• Last push: 2026-03-19, with no releases or tags.
• Stars and forks: 603 and 48 at review; 617 and 48 on 2026-10-21.
• Forks elsewhere: trendshift shows 52 forks on 2026-10-21.
• Copies: GitHub code search found 2, including the original.
• Hash: the macOS SKILL.md sha256 starts with 9fa44a38.

What are the alternatives to Platform Design Skills?

The closest alternatives to Platform Design Skills are two evaluated skills. Ibelick's UI Skills (72, Recommended with caveats) reviews React and Tailwind work. Vercel's Web Design Guidelines (66, Conditional) checks web UI files.

Expo's skills (expo/skills) are another alternative, which we have not evaluated.

Common questions

Does the Apple HIG PDF in the repo load into context?

No. The 2.4 MB Apple_HIG.pdf sits at the repo root, and no skill references it.

Is Emil Kowalski's apple-design skill the same thing?

No. It is a separate skill from a different publisher, and we have not evaluated it.

Are Platform Design Skills free?

Yes. They are MIT-licensed.

Which platform skill is installed most?

The macOS skill, with 4.0K skills.sh installs at review.