Liquid Glass

Liquid Glass — the material

Composed 2026-08 and verified against developer.apple.com and SDK interfaces. Every rule carries an availability floor and a confidence tag: [verified] (checked against Apple docs/SDK this composition), [apple] (Apple doc, unverified), [multi] (corroborated by multiple independent accounts), [single] (one account — verify before relying), [version-pinned] (bug workaround tied to OS versions; recheck on updates).

Operating rules

1. ALWAYS read references/availability-and-sdk27.md before generating or reviewing glass

code. It corrects availability errors present in most published material, including Apple's.

1. Load other references on demand via the router below — one topic, one file.
2. Glass belongs on the functional layer (controls, chrome) floating above the content layer.

When asked to add glass to content (lists, media, text), first ask whether it should be glass at all.

1. Prefer standard components (toolbars, search, sheets, tab bars) that adopt glass

automatically; custom glassEffect surfaces are for distinctive elements only.

1. Never present simulator rendering or exact screenshot pixels as evidence a glass change is

correct — see references/known-bugs-and-testing.md.

1. Animation of glass (morphing, transitions, reduce-motion gating, performance) is owned by

the companion liquid-glass-motion skill, installed alongside this one. Read its references when the task involves motion; do not improvise glass animation from here.

Workflows

• Review existing glass → references/review-checklist.md (diff-checkable items +

known-bad API table). Also flag where glass should NOT be used.

• Adopt / migrate an app → references/fallback-and-migration.md (deletion-first audit,

5 phases), then per-surface references.

• Implement from scratch → references/material-and-variants.md +

references/containers-and-sampling.md, then the platform file for your framework.

Hard rules (the short list)

1. Availability-gate every glass API per platform with its real floor; fall back to Materials

below 26. [verified]

1. Never wrap glassEffect in a .if conditional-modifier helper — ternary with .identity

or a ViewModifier gate instead. [apple]

1. Apply glassEffect after layout and appearance modifiers. [multi]
2. Two or more glass views near each other → one GlassEffectContainer. Glass cannot sample

other glass; the container is visual correctness, not just performance. [multi]

1. interactive() only on surfaces that actually respond to interaction; buttons already

have it. [multi]

1. Never set opacity < 1 on a glass view or any ancestor — refraction silently collapses.

[multi]

1. Glass needs content to refract: over a flat single-color background it reads as a flat

tinted rectangle. Give it a gradient/image/dynamic content, or don't use glass. [multi]

1. Never stack glass on glass. [multi]
2. Custom-shape glass buttons need contentShape or only the glyph hit-tests.

[version-pinned]

1. Glass ignores .allowsHitTesting(false); only .disabled(true) suppresses its visual

reaction. [verified]

1. The system adapts the material for Reduce Transparency / Increase Contrast — don't

fight it, and don't remove glass manually where the system would frost it. [multi]

1. Dark/muddy glass over bright backgrounds in Dark Mode is by design; fix the background

colors, not the glass. [verified]

Topic router

| Topic | Reference | |---|---| | Availability, SDK-27 breakages, renames, compat flag | references/availability-and-sdk27.md (always) | | Variants, tint, shapes, interactive, when-to-use | references/material-and-variants.md | | Containers, sampling, spacing, glass-on-glass | references/containers-and-sampling.md | | Toolbars, scroll edge, tab bar, WWDC26 toolbar APIs | references/toolbars-and-scroll-edge.md | | UIKit (UIGlassEffect, corners, hosting) | references/uikit-glass.md | | AppKit, NSGlassEffectView, Mac windows, Tahoe chrome | references/appkit-and-mac-windows.md | | Accessibility (transparency, contrast, hit targets) | references/accessibility.md | | Fallbacks below 26, migration workflow | references/fallback-and-migration.md | | Version-pinned bugs, testing/screenshot policy | references/known-bugs-and-testing.md | | Review audit + known-bad (hallucinated) APIs | references/review-checklist.md | | Morphing, glassEffectID, transitions, motion, Metal, profiling | liquid-glass-motion skill |

Scope

SwiftUI first; UIKit and AppKit covered; WidgetKit briefly in platform files. visionOS excluded — the SDK marks Liquid Glass unavailable there [verified]. watchOS/tvOS excluded — no reliable source material exists; do not improvise.

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: YordiLorenzo
• Source: YordiLorenzo/liquid-glass-skills
• License: MIT

Install and usage instructions live in the source repository linked above.