Apple Text

Agent Skills for Apple's text stack: TextKit 1 and 2, UITextView, NSTextView, AttributedString, Core Text, Writing Tools, and the iOS 26 SwiftUI TextEditor.

Install

# Any agent (Vercel skills CLI)
npx skills add sitapix/apple-text

# Claude Code
/plugin marketplace add sitapix/apple-text
/plugin install apple-text@apple-text

For Claude Code installs, prefix slash commands with apple-text: (e.g., /apple-text:txt-audit).

Skills

Diagnostics

Skill	Covers
txt-audit	Severity-ranked code review
txt-textkit-debug	Symptom-driven diagnosis
txt-fallback-triggers	TextKit 2→1 fallback catalog
txt-snippets	Quick recipes

Picking an API

Skill	Covers
txt-view-picker	Which text view to use
txt-textkit-choice	TextKit 1 vs 2
txt-attributed-string	AttributedString vs NSAttributedString
txt-appkit-vs-uikit	NSTextView vs UITextView
txt-swiftui-texteditor	iOS 26 SwiftUI TextEditor

TextKit & layout

Skill	Covers
txt-textkit1	TextKit 1 reference
txt-textkit2	TextKit 2 reference
txt-nstextstorage	NSTextStorage subclassing
txt-viewport-rendering	Viewport, fragments, rendering attributes
txt-layout-invalidation	The invalidation model
txt-exclusion-paths	Wrapping around shapes, multi-column
txt-line-breaking	Hyphenation, truncation, paragraph spacing
txt-measurement	boundingRect, sizeThatFits
txt-core-text	Glyph-level access

Attributes & content

Skill	Covers
txt-attribute-keys	NSAttributedString.Key catalog
txt-attachments	Inline images, Genmoji
txt-markdown	Markdown in SwiftUI Text and AttributedString
txt-colors	Text colors, dark mode, HDR
txt-detectors-tagger	NSDataDetector, NLTagger, NLTokenizer

Editing & input

Skill	Covers
txt-uitextinput	UITextInput / NSTextInputClient
txt-selection-menus	Selection UI, edit menus, gestures
txt-find-replace	UIFindInteraction, NSTextFinder
txt-spell-autocorrect	UITextChecker, NSSpellChecker
txt-undo	NSUndoManager grouping
txt-pasteboard	Copy/cut/paste, format stripping
txt-drag-drop	UITextDraggable, UITextDroppable
txt-bidi	RTL, bidirectional text
txt-regex	Swift Regex vs NSRegularExpression

SwiftUI bridging

Skill	Covers
txt-swiftui-interop	What crosses the SwiftUI/TextKit boundary
txt-wrap-textview	UIViewRepresentable around UITextView/NSTextView

Modern & maintenance

Skill	Covers
txt-writing-tools	UIWritingToolsCoordinator, behavior, ignored ranges
txt-dynamic-type	UIFontMetrics, adjustsFontForContentSizeCategory
txt-accessibility	VoiceOver, accessibilityTextualContext
txt-apple-docs	Sosumi + xcrun mcpbridge
txt-refresh-against-sosumi	Refresh latest-apis.md after Xcode releases

Example prompts

Phrasings that route to the right skill, including ones that don't name the API.

Diagnose a bug

Prompt	Triggers
"Writing Tools stopped showing the inline rewrite animation — only the floating panel opens now. Started after we added a custom NSTextStorage."	txt-fallback-triggers
"Lines in our editor sometimes render half-drawn — descenders chopped, characters bleeding into the next paragraph."	txt-textkit-debug
"Cursor jumps to the end every time my SwiftUI binding pushes new text into the wrapped UITextView."	txt-wrap-textview
"Cmd-Z undoes one character at a time after a paste — should be one step."	txt-undo
"Diacritics get clipped at the top of my custom NSTextLayoutFragment."	txt-viewport-rendering
"boundingRect returns a single-line size for multi-line text."	txt-measurement
"Cursor jumps unpredictably when I type Arabic mixed with English."	txt-bidi
"VoiceOver skips punctuation in our code editor."	txt-accessibility

Pick an API

Prompt	Triggers
"Starting a new code editor — TextKit 1 or TextKit 2?"	txt-textkit-choice
"AttributedString or NSAttributedString for a notes-app model?"	txt-attributed-string
"Multi-line search box in SwiftUI — TextField or TextEditor?"	txt-view-picker
"Porting our Mac editor to iPad — what AppKit features have no UIKit equivalent?"	txt-appkit-vs-uikit

Build a feature

Prompt	Triggers
"How do I add a placeholder to UITextView?"	txt-snippets
"Wrap article text around an inline circular thumbnail."	txt-exclusion-paths
"Add cmd-F find UI to my UITextView with replace-all."	txt-find-replace
"Drop an image into my editor as an inline attachment."	txt-drag-drop
"Rewrite is mangling code blocks in our doc editor — protect them from Writing Tools."	txt-writing-tools
"Bind AttributedString to TextEditor on iOS 26 with a formatting toolbar."	txt-swiftui-texteditor
"Building a canvas-based code editor and the keyboard / autocorrect / magnifier are wrong."	txt-uitextinput

Audit and maintenance

Prompt	Triggers
"Review our text-editor module before we ship — flag fallback risks and deprecated APIs."	txt-audit
"Refresh the skills against current Apple docs now that Xcode 26.4 is out."	txt-refresh-against-sosumi
"Look up the current AttributedString(markdown:) initializer signature."	txt-apple-docs

Contributing

AGENTS.md covers authoring rules, anti-patterns, and the freshness contract. references/topic-boundaries.md explains sibling splits. Skill content links to sosumi.ai instead of developer.apple.com (the latter renders with JavaScript and returns a stub to non-browser fetches).