A guide to building advanced layouts and scrolling containers in SwiftUI, Apple's user-interface framework for Swift apps. It covers custom layouts, grids, reusable containers, and lazy scrolling, which loads list content as needed.

Use it when creating custom SwiftUI containers, equal-width controls, grids, carousels, paging, programmatic scrolling, or long scrolling lists.

It helps avoid common layout, sizing, scrolling, and performance problems when basic stacks are not enough.

layout — Skill for Claude Code by rshankras/claude-code-apple-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 rshankras/claude-code-apple-skills --skill layout

Clone the repo

git clone --depth 1 https://github.com/rshankras/claude-code-apple-skills

Made for: Claude Code.

Or install apple-skills, the plugin that ships this one along with the rest of its 182 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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/rshankras/claude-code-apple-skills/layout/github.svg)](https://agentmods.dev/skills/rshankras/claude-code-apple-skills/layout)

Your own site

<a href="https://agentmods.dev/skills/rshankras/claude-code-apple-skills/layout"><img src="https://agentmods.dev/badge/skills/rshankras/claude-code-apple-skills/layout/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/rshankras/claude-code-apple-skills/layout"><img src="https://agentmods.dev/badge/skills/rshankras/claude-code-apple-skills/layout.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 78 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,716 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.

Model	Per session	Once invoked
Fable 5.1	$0.00078	$0.01716
Opus 5.5	$0.00031	$0.00686
Sonnet 5.5	$0.00016	$0.00343
Haiku 4.5	$0.00008	$0.00172

Measured 2d ago against content hash b25bce8fc57b, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

layout 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 2d 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.

skills/swiftui/layout/SKILL.md · 118 lines

How it starts

The opening of the file, as written. The whole thing — 118 lines — stays where its author put it; the contents beside it link to each section on GitHub.

SwiftUI Layout & Containers

The layer between "stacks and spacers" and "it scrolls like butter with 100k rows" — Apple's Layout protocol, container composition, and the lazy-stack rules from the WWDC26 deep dive. View identity/data-flow questions route to swiftui/data-flow.

When This Skill Activates

"Make these buttons equal width" / measurement-dependent layout
Building a reusable container (custom List/board/carousel) that should accept ForEach + sections
Lazy stack jank, memory growth, scroll-position bugs, broken scroll targeting
Programmatic scrolling, paging/snapping, scroll-linked effects
GeometryReader causing layout loops or mangled sizing

Custom Layout protocol (not GeometryReader)

Reach for a custom Layout whenever you must measure subviews and feed the measurement back into layout — GeometryReader only measures its container and can't influence the engine. Canonical case: equal-width buttons.

sizeThatFits: propose .unspecified to read each subview's ideal size (subviews.map { $0.sizeThatFits(.unspecified) }); guard empty subviews; replacingUnspecifiedDimensions() for nil proposal dimensions.
placeSubviews: never assume origin (0,0) — use bounds.minX/midX (non-zero origins are what make layouts composable); place(at:anchor:proposal:) with a proposal that may differ from the ideal size (that's how equal widths happen).
Respect spacing preferences: subviews[i].spacing.distance(to:along:), taking the larger of conflicting preferences — matching built-in containers. No hardcoded 8s.
Per-subview data via LayoutValueKey (+ a layoutValue convenience modifier), read as subview[Key.self].
Cache only after Instruments shows layout cost — it's an optimization, not a requirement.
Switch layouts without killing identity: AnyLayout(HStackLayout()) ↔ custom layout with .animation(_:value:) — SwiftUI sees one changing view, so state survives and it animates.
Don't build fallbacks into the layout — wrap alternatives in ViewThatFits.

Read the full file on GitHub · 118 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.

2d ago First seen · 118 lines · 78 tokens per session scan A b25bce8fc57b

Subscribe to this mod's changes

layout is a skill published in the GitHub repository rshankras/claude-code-apple-skills (864 stars, last pushed 2d ago), licensed MIT. It adds 78 tokens to every session and 1,716 once invoked, about $0.0003 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 2026-11-05.

Kotlin and Swift Languages Mobile agent-skills anthropic app-store apple aso claude

layout next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
layoutrshankras/claude-code-apple-skills	Skill	864	2d ago	MIT	A	78	Claude Code
swift-expertpersonamanagmentlayer/pcl	Skill	44	11d ago	Apache-2.0	A	76	Claude Code
ios-expertpersonamanagmentlayer/pcl	Skill	44	11d ago	Apache-2.0	A	64	Claude Code
ios-swiftui-productJasonColapietro/ios-app-dev-skills	Skill	9	2mo ago	MIT	A	67	Codex
swiftui-maxDev869/swift-tothemax	Skill	7	4mo ago	MIT	A	271	Claude Code
apple-dev-conductorDev869/swift-tothemax	Skill	7	4mo ago	MIT	A	156	Claude Code
kotlin-patternssoftspark/ai-toolkit	Skill	179	10d ago	Apache-2.0	A	51	Claude Code