macos-patterns

A reference for native macOS development patterns that web developers may not know. It explains menu-bar apps, windows, keyboard shortcuts, file pickers, clipboard access, drag and drop, and screen-related features.

In plain words
What is it for?
Use it when building native macOS apps, especially menu-bar apps, floating panels, custom windows, keyboard shortcuts, file interactions, clipboard features, or drag-and-drop behavior.
Why use it?
It helps prevent web-development assumptions from producing macOS code that behaves incorrectly or does not follow the platform's conventions.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/recomposesh/recompose/macos-patterns
Any agent
npx skills add recomposesh/recompose --skill macos-patterns
Clone the repo
git clone --depth 1 https://github.com/recomposesh/recompose

Made for: Claude Code, Codex.

Per session 159 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,346 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 100% copy Near-identical to another mod 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.

ModelPer sessionOnce invoked
Fable 5 $0.00159 $0.04346
Opus 5 $0.00079 $0.02173
Sonnet 5 $0.00032 $0.00869
Haiku 4.5 $0.00016 $0.00435

Measured 2d ago against content hash b1dd249b315a, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

macos-patterns 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.

Origin

This is a copy

100% identical to macos-patterns — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

.agents/skills/macos-patterns/SKILL.md · 591 lines

How it starts

The opening of the file, as written. The whole thing — 591 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Native macOS Patterns for Web Developers

This is a reference guide for the macOS-specific patterns that have no web equivalent. When building a native macOS app, these are the things that trip up everyone coming from web development. The AI should consult this before generating macOS code to avoid confidently producing patterns that don't work.

There are two approaches. Use MenuBarExtra for simple menus, NSStatusItem for full control.

SwiftUI MenuBarExtra (simple)

@main
struct MyApp: App {
    var body: some Scene {
        MenuBarExtra("MyApp", image: "MenuBarIcon") {
            MenuBarView()
        }
    }
}

This creates a menu-bar-only app. The menu content is a standard SwiftUI view. For a popover-style menu bar app (richer UI than a plain menu), use the .window style:

MenuBarExtra("MyApp", image: "MenuBarIcon") {
    PopoverContentView()
}
.menuBarExtraStyle(.window)

AppKit NSStatusItem (full control)

For custom menus, dynamic icons, or complex interactions:

let statusItem = NSStatusBar.system.statusItem(withLength: NSStatusItem.squareLength)
if let button = statusItem.button {
    let icon = NSImage(named: "MenuBarIcon")!
    icon.size = NSSize(width: 18, height: 18)
    icon.isTemplate = true  // CRITICAL: adapts to dark/light mode automatically
    button.image = icon
}

let menu = NSMenu()
menu.addItem(NSMenuItem(title: "Settings...", action: #selector(openSettings), keyEquivalent: ","))
statusItem.menu = menu

isTemplate = true is essential. Without it, your icon will be invisible in light mode or look wrong in dark mode.

NSPopover for Rich Menu Bar Content

For a popover attached to the menu bar icon (like Bartender, iStatMenus):

let popover = NSPopover()
popover.contentSize = NSSize(width: 300, height: 400)
popover.behavior = .transient  // auto-closes when clicking outside
popover.contentViewController = NSHostingController(rootView: MyPopoverView())

// Show from the status item button:
if let button = statusItem.button {
    popover.show(relativeTo: button.bounds, of: button, preferredEdge: .minY)
}

Read the full file on GitHub · 591 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.

  1. 2d ago First seen · 591 lines · 159 tokens per session scan A b1dd249b315a

Subscribe to this mod's changes

macos-patterns is a skill published in the GitHub repository recomposesh/recompose (25 stars, last pushed 5d ago), licensed MIT. It adds 159 tokens to every session and 4,346 once invoked, about $0.0008 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to macos-patterns, differing in 0 lines, and is treated as a copy.

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