App Icon Generator Skill

App Icon Generator

Generate an app icon programmatically with a CoreGraphics Swift script, resize it to every required size, and install it into the Xcode asset catalog — with appearance variants (light/dark/tinted).

Read first — the Liquid Glass era (iOS 26 / macOS 26)

Apple icon standards verified as of July 2026 — Icon Composer, Xcode 26, macOS Tahoe 26.4+. This guidance is static (the skill does no per-run web lookup); if that date is well in the past or the OS has moved on, re-verify against the HIG · App icons before trusting the specifics below.

Apple's shippable icon format changed. On iOS 26 / macOS 26 the modern app icon is a layered, light-responsive Liquid Glass icon authored in Icon Composer (free; ships with Xcode 26, needs macOS Tahoe 26.4+). You supply flat artwork in up to four depth groups (background → foreground); the system renders the glass — specular highlights, refraction, translucency, shadows — and masks the rounded-rect shape. One .icon file adapts across iPhone, iPad, Mac, and Apple Watch and across Default / Dark / Mono (tinted) appearances.

So this skill does NOT produce the final iOS 26 icon. Icon Composer is GUI-first; no script can author a true layered .icon. Its two honest roles are:

Placeholder — a fast flat 1024 PNG so early builds, TestFlight, and screenshots feel real before you invest in the real icon.
Layered source art — flat background / midground / foreground PNGs (or SVGs), effect-free, ready to drag into Icon Composer, where you assemble depth and export the .icon.

What changed vs. the classic flow:

Do not bake in lighting. No pre-painted specular highlights, drop shadows, or gradients-used-as-lighting — the system owns those now, and baking them in double-exposes against the system glass. (The drawShine/drawShadow blocks below are legacy-only, off by default for iOS 26+ targets.)
Do not round the corners. Icon Composer / the system apply the shape mask — fill a full square canvas.
SVG for shapes, PNG for effects — vector where you can, raster only where you must.
Provide appearance variants — light (default), dark, and tinted/mono. A single flat PNG only fills the light slot and won't adapt on iOS 18+.

Detect the target first: read the deployment target (IPHONEOS_DEPLOYMENT_TARGET / MACOSX_DEPLOYMENT_TARGET in the pbxproj, or .planning/APP.md). iOS 26+ / macOS 26+ → lead with the Icon Composer handoff and treat the flat PNG as a placeholder. Older targets → the classic flat + appearances path is fine to ship. If the deployment target is newer than the "verified as of" date above, flag it to the user and re-verify the icon rules against the current HIG before generating — the skill won't know about anything Apple shipped after that date.

When This Skill Activates

Use this skill when the user:

Asks to "generate an app icon" or "create an icon"
Wants a "placeholder icon" or "app icon design"
Mentions "icon for my app" or "need an app icon"
Asks to "update the app icon"

Pre-Generation Checks

1. Project Context Detection

Glob: **/Assets.xcassets/AppIcon.appiconset/Contents.json

Identify platform: macOS, iOS, or universal
Check for existing icon files (warn before overwriting)
Read Contents.json to understand required sizes

2. App Context Detection

Gather app information to customize the icon:

Read: .planning/APP.md          (if exists — app definition)
Read: .planning/CODEBASE.md     (if exists — app description)
Grep: "CFBundleName" or app name in project files

If no planning files exist, ask the user.

Configuration Questions

Ask via AskUserQuestion:

Question 1: App Category

"What category best describes your app?"

Productivity — Clean geometric shapes, blues/teals
Creative/Media — Vibrant colors, camera/brush/music motifs
Developer Tools — Dark backgrounds, terminal/code symbols
Utilities — Functional shapes, neutral/system colors

Question 2: Visual Style

"What visual style do you prefer?"

Bold Symbol — Single prominent shape/icon centered (like the record button)
Contained Scene — A scene inside a shape (like a monitor with elements)
Abstract Mark — Geometric/abstract design (like viewfinder brackets)
Gradient Glyph — SF Symbol-style glyph on gradient background

Question 3: Color Palette

"What color palette fits your app?"

Deep Blue/Indigo — Professional, trustworthy (navy #0f0c29 to indigo #302b63)
Teal/Cyan — Fresh, modern (dark teal #0a1628 to blue #1a4a6b)
Purple/Violet — Creative, premium (midnight #1a0533 to violet #4a1a8a)
Warm/Orange — Energetic, friendly (dark red #2d1117 to orange #c0392b)

Question 4: Accent Color

"What accent color for the focal element?"

Red — Attention, recording, alerts (#ff453a to #d63031)
Blue — Trust, communication (#007aff to #0056b3)
Green — Success, nature, health (#34c759 to #248a3d)
Gold/Yellow — Premium, energy (#ffd60a to #c7a600)

Apple HIG Icon Guidelines

Read apple-hig-icons.md before generating.

Timeless rules (all eras):

No text in the icon — must be universally recognizable
Single focal point — one clear element the eye is drawn to
Simple shapes — legible at 16×16 (macOS menu bar) and at Home-screen size
Fill a full square canvas — never bake in rounded corners; the system / Icon Composer apply the shape mask
Front-facing — no 3D tilts or dramatic angles
Ensure contrast — the focal element must stand out from the background
Platform-appropriate detail — macOS can be more detailed (displays larger); iOS simpler

Liquid Glass era rules (iOS 26 / macOS 26):

The system owns lighting. No baked specular, drop shadows, or gradients-as-lighting — Icon Composer / the system add depth, refraction, and highlights. Keep artwork flat.
Provide appearance variants — light (default), dark, and tinted/mono. Make sure the mark reads on all three (tinted renders as a monochrome silhouette on a system-tinted background).
Layer, don't flatten (final icon) — organize art into ≤4 depth groups for Icon Composer; SVG for shapes, PNG only for texture.

Designing the Icon (Apple's Rules)

Design-layer guidance from Apple's icon sessions (WWDC25) plus evergreen craft tests. The numbered rules above are the hard constraints; this is how to make the artwork good.

Composition

One 1024×1024 canvas drives every platform — except watchOS, which uses 1088×1088, deliberately overshooting the circular mask so edge-to-edge art survives the crop. Either way the system applies the mask.
Frontal, flat illustration beats realistic 3D/perspective rendering — the glass material supplies the dimensionality, so pre-rendered depth fights it.
Fewer, rounder layers beat dense detail. Avoid sharp edges and thin lines: rounder corners carry the glass lighting; bolder weights survive small sizes.
Soft gradients over flat fills. For backgrounds, prefer the built-in System Light / System Dark gradients to pure white or black.
Colored backgrounds keep light, dark, and tinted modes distinct — a neutral field collapses across appearances.
Translucency and blur are encouraged, not risky: clear mode shows the wallpaper through the glass, so translucent layers are rewarded.

Appearance modes

Author three variants — default, dark, mono — and the system derives six renders: default, dark, clear light/dark, tinted light/dark. Preview all six before shipping.

Icon Composer craft details

Export artwork flat and opaque, each color region split into its own layer; SVG for flat graphics (convert text to outlines first), PNG for gradients and raster; export at canvas size.
Prefix layer filenames with a Z-order number so stacking imports deterministically.
Glass is applied per layer — if a narrow shape turns "pillowy", toggle that layer's specular off.
Tune per appearance: swap any fill that vanishes against black in dark mode; in mono keep one prominent white element and step the rest down to grays.
Choose neutral vs chromatic shadows per layer — chromatic tints the shadow with the layer's color, better for colorful art on light backgrounds.
Test on real wallpapers, with the grid overlay, and at small sizes — then ship the exported .icon into Xcode.

Classic tests (evergreen)

One identifiable metaphor — if you can't name the single thing the icon depicts, users can't either.
Squint test inside a folder: still distinguishable among its neighbors?
Check the Settings-list render, not only the Home Screen (Step 4.6) — it's the smallest surface users see daily.
Align key shapes to the icon grid for optical balance (a guide, not a straitjacket).
An icon is identity with lineage — refine it release over release; don't redesign from scratch every update.

Generation Process

Step 1: Determine Icon Design

Based on the user's answers (or app context), select:

Background: Gradient direction, colors, optional radial glow
Primary Element: The main shape/symbol
Secondary Elements: Optional ring, glow, accent shapes
Style Modifiers: stroke weight (⚠️ skip Shine/shadow for iOS 26+ targets — the system applies Liquid Glass specular and shadow; baking them in double-exposes)

Step 2: Generate Swift Script

Create a self-contained Swift script at scripts/generate-icon.swift that:

Uses import AppKit and CoreGraphics (no dependencies)
Generates 3 variants at 1024x1024
Saves to icon-variants/ directory
Uses the design parameters from Step 1

Script structure:

#!/usr/bin/env swift
import AppKit
import CoreGraphics

let size: CGFloat = 1024
// ... helper functions (gradients, glows, shapes)
// ... variant generation functions
// ... save and output

Design building blocks (combine these based on category/style):

| Building Block | Function | Use For | |---------------|----------|---------| | drawGradientBackground | Linear gradient fill | All icons | | drawRadialGlow | Soft colored glow behind focal element | Adding depth | | drawCircle | Filled/stroked circle | Record buttons, dots, orbs | | drawRoundedRect | Rounded rectangle | Screens, cards, containers | | drawRing | Circle outline | Borders, focus rings | | drawBrackets | Corner bracket marks | Viewfinders, capture | | drawMonitor | Screen + stand shape | Screen/display apps | | drawShield | Shield outline | Security/privacy apps | | drawGear | Gear/cog shape | Settings/utility apps | | drawWaveform | Audio waveform bars | Audio/music apps | | drawDocument | Page with fold corner | Document/writing apps | | drawShine | Elliptical specular highlight | ⚠️ Legacy only — off for iOS 26+ (system paints its own specular) | | drawShadow | Drop shadow beneath element | ⚠️ Legacy only — off for iOS 26+ (system casts its own shadow) |

Step 3: Run Script and Present Variants

swift scripts/generate-icon.swift

Show all 3 variants to the user using the Read tool (Claude can view images). Ask the user to pick one, or request adjustments.

Step 4: Resize and Install

Once the user picks a variant:

Resize using sips (built into macOS):

For macOS (10 sizes):

sips -z 16 16     master.png --out icon_16x16.png
sips -z 32 32     master.png --out icon_16x16@2x.png
sips -z 32 32     master.png --out icon_32x32.png
sips -z 64 64     master.png --out icon_32x32@2x.png
sips -z 128 128   master.png --out icon_128x128.png
sips -z 256 256   master.png --out icon_128x128@2x.png
sips -z 256 256   master.png --out icon_256x256.png
sips -z 512 512   master.png --out icon_256x256@2x.png
sips -z 512 512   master.png --out icon_512x512.png
sips -z 1024 1024 master.png --out icon_512x512@2x.png

For iOS (single 1024x1024):

cp master.png icon_1024x1024.png

Write Contents.json for the asset catalog

For macOS:

{
  "images": [
    { "filename": "icon_16x16.png", "idiom": "mac", "scale": "1x", "size": "16x16" },
    { "filename": "icon_16x16@2x.png", "idiom": "mac", "scale": "2x", "size": "16x16" },
    { "filename": "icon_32x32.png", "idiom": "mac", "scale": "1x", "size": "32x32" },
    { "filename": "icon_32x32@2x.png", "idiom": "mac", "scale": "2x", "size": "32x32" },
    { "filename": "icon_128x128.png", "idiom": "mac", "scale": "1x", "size": "128x128" },
    { "filename": "icon_128x128@2x.png", "idiom": "mac", "scale": "2x", "size": "128x128" },
    { "filename": "icon_256x256.png", "idiom": "mac", "scale": "1x", "size": "256x256" },
    { "filename": "icon_256x256@2x.png", "idiom": "mac", "scale": "2x", "size": "256x256" },
    { "filename": "icon_512x512.png", "idiom": "mac", "scale": "1x", "size": "512x512" },
    { "filename": "icon_512x512@2x.png", "idiom": "mac", "scale": "2x", "size": "512x512" }
  ],
  "info": { "author": "xcode", "version": 1 }
}

For iOS (single size, system generates others):

{
  "images": [
    { "filename": "icon_1024x1024.png", "idiom": "universal", "platform": "ios", "size": "1024x1024" }
  ],
  "info": { "author": "xcode", "version": 1 }
}

Copy files into the asset catalog directory
Build to verify: xcodebuild build -scheme <scheme> -destination 'platform=<platform>' -quiet

Step 4.5: Appearance variants & Icon Composer handoff

Appearance variants (iOS 18+, scriptable). For the flat path, generate three 1024 PNGs — light (default), dark, and a monochrome/tinted mark — and declare them so the icon adapts to the user's Home screen:

{
  "images": [
    { "filename": "icon_light.png",  "idiom": "universal", "platform": "ios", "size": "1024x1024" },
    { "filename": "icon_dark.png",   "idiom": "universal", "platform": "ios", "size": "1024x1024",
      "appearances": [ { "appearance": "luminosity", "value": "dark" } ] },
    { "filename": "icon_tinted.png", "idiom": "universal", "platform": "ios", "size": "1024x1024",
      "appearances": [ { "appearance": "luminosity", "value": "tinted" } ] }
  ],
  "info": { "author": "xcode", "version": 1 }
}

Icon Composer handoff (iOS 26+ / the shippable icon). The flat PNGs above are a placeholder. For the real Liquid Glass icon:

Export the design as flat layers — background, midground, foreground — as SVG (shapes) or PNG (texture), with no baked highlights, shadows, or corners.
Open Icon Composer (Xcode 26 ▸ Open Developer Tool ▸ Icon Composer; needs macOS Tahoe 26.4+). Drag the layers in, organize into ≤4 depth groups, tune specular / refraction / translucency / shadow (don't overdo refraction), and check the Default / Dark / Mono previews.
Export .icon and add it to the target (it replaces the AppIcon set). Icon Composer also exports a flattened 1024 PNG for App Store marketing.

This is a manual GUI step by design — the skill prepares the layers and hands off; it does not author the .icon.

Step 4.6: Validate Before Install (hard checks — do not skip)

An icon that "looks fine" as a 1024px file on a neutral canvas can still fail on a real Home Screen. All three checks below caught real shipped bugs:

Adjacent-element contrast. Any mark element that touches the icon background (a header band, badge ring, tab, outline) must clearly contrast with that background — same-hue-slightly-darker vanishes at Home Screen size, amputating part of the mark. Elements sitting on the card/mark interior only need contrast against the card.
Judge at 60–64 px, not 1024. sips -Z 120 each variant and Read the small render — that's the size users see. Subtle contrast that survives at 1024 dies at 60.
Tinted variant must be strictly grayscale. iOS 18+ overlays the user's tint on the tinted variant; baked-in color renders wrong. Beware colors hardcoded inside shared draw functions — the tinted call site can pass gray arguments while the function paints brand color anyway. Parametrize every color per variant, then verify the exported PNG has zero saturation (e.g. a quick pixel scan).
See it in place (required, not optional). Build to a simulator and screenshot the Home Screen — the icon among other apps on a real wallpaper is the only honest review. Check light, dark, and tinted appearances.

Step 5: Cleanup

Keep scripts/generate-icon.swift for future regeneration
Remove icon-variants/ directory (or add to .gitignore)

Category-Specific Design Recipes

Productivity Apps

Background: Deep blue (#0f1b3d) to teal (#1a4a6b)
Element: Checkmark, list, or document shape in white
Accent: Green checkmark or blue highlight
Style: Clean, minimal, professional

Creative/Media Apps

Background: Dark purple (#1a0533) to magenta (#6b1a5c)
Element: Camera lens, brush stroke, play button, or waveform
Accent: Red record dot, orange/yellow creative spark
Style: Vibrant, expressive

Developer Tools

Background: Near-black (#0d1117) to dark gray (#1a1a2e)
Element: Terminal bracket >_, code braces {}, or gear
Accent: Green (#34c759) or cyan (#00d4ff) terminal glow
Style: Monospace feel, technical

Communication Apps

Background: Blue (#0a2463) to lighter blue (#1e5aa8)
Element: Speech bubble, person silhouette, or connection lines
Accent: White or light blue
Style: Friendly, approachable

Utility Apps

Background: Dark gray (#1a1a2e) to medium gray (#2d2d44)
Element: Gear, wrench, shield, or lightning bolt
Accent: System blue (#007aff) or orange (#ff9500)
Style: Functional, trustworthy

Finance Apps

Background: Dark green (#0a2e1a) to emerald (#1a6b3a)
Element: Chart line, coin, or dollar symbol
Accent: Gold (#ffd60a) or green (#34c759)
Style: Secure, premium

Health/Fitness Apps

Background: Dark red (#2d1117) to pink (#6b1a3a)
Element: Heart, activity ring, or pulse line
Accent: Red (#ff3b30) or green (#34c759)
Style: Energetic, motivating

Education Apps

Background: Deep blue (#0f0c29) to royal blue (#302b63)
Element: Book, graduation cap, or lightbulb
Accent: Yellow (#ffd60a) or white
Style: Inspiring, trustworthy

Output Summary

After completion, report:

Icon installed!

Type:     [placeholder flat icon | classic icon + appearances]
Master:   scripts/generate-icon.swift (re-run to regenerate)
Sizes:    [list] · appearances: [light/dark/tinted]
Location: [path to AppIcon.appiconset]

⚠️ For an iOS 26+ / macOS 26+ target this is a PLACEHOLDER. Finish the real
   Liquid Glass icon in Icon Composer (see the handoff step) before submitting.

Build and run to see it: Home screen (iOS) · menu bar / Finder / Spotlight (macOS).

Iteration

If the user wants changes:

Modify the Swift script parameters (colors, shapes, sizes)
Re-run: swift scripts/generate-icon.swift
Show the updated variants
Resize and reinstall once approved

Common adjustment requests:

"Make the record dot bigger/smaller" → adjust radius parameter
"Different background color" → change gradient hex values
"Add more depth" → add a radial glow (⚠️ not baked shine on iOS 26+ — add depth in Icon Composer instead)
"Too busy, simplify" → remove secondary elements
"Doesn't look good at small size" → increase stroke widths, simplify shapes

Agent Skills: App Icon Generator

Install this agent skill to your local

Skill Files