Claude Skills
The open format is called Agent Skills and works in Claude Code, Codex, Cursor and other agents — most people know it as Claude Skills.
Every Agent Skill we could find on GitHub, deduplicated by content. 79 437 files from 1 744 authors, of which 61 785 are unique — the rest is the same skill repackaged into someone else's repository. For each one: what it weighs in tokens, whether it ships runnable scripts, and which MCP servers it needs.
Use when debugging Foundation Models issues — context exceeded, guardrail violations, slow generation, availability problems, unsupported language, or unexpected output. Systematic diagnostics with production crisis defense.
Reference — Complete Foundation Models framework guide covering LanguageModelSession, @Generable, @Guide, Tool protocol, streaming, dynamic schemas, built-in use cases, and all WWDC 2025 code examples
Use when implementing on-device AI with Apple's Foundation Models framework — prevents context overflow, blocking UI, wrong model use cases, and manual JSON parsing when @Generable should be used. iOS 26+, macOS 26+, iPadOS 26+, axiom-visionOS 26+
Use when first installing Axiom, unsure which skill to use, want an overview of available skills, or need help finding the right skill for your situation — interactive onboarding that recommends skills based on your project and current focus
Use when writing raw SQL queries with GRDB, complex joins, ValueObservation for reactive queries, DatabaseMigrator patterns, query profiling under performance pressure, or dropping down from SQLiteData for performance - direct SQLite access for iOS/macOS
Use when app freezes, UI unresponsive, main thread blocked, watchdog termination, or diagnosing hang reports from Xcode Organizer or MetricKit
Use when implementing haptic feedback, Core Haptics patterns, audio-haptic synchronization, or debugging haptic issues - covers UIFeedbackGenerator, CHHapticEngine, AHAP patterns, and Apple's Causality-Harmony-Utility design principles from WWDC 2021
Reference — Comprehensive Apple Human Interface Guidelines covering colors (semantic, custom, patterns), backgrounds (material hierarchy, dynamic), typography (built-in styles, custom fonts, Dynamic Type), SF Symbols (rendering modes, color, axiom-localization), Dark Mode, accessibility, and platform-specific considerations
Use when making design decisions, reviewing UI for HIG compliance, choosing colors/backgrounds/typography, or defending design choices - quick decision frameworks and checklists for Apple Human Interface Guidelines
Use when implementing 'iCloud Drive', 'ubiquitous container', 'file sync', 'NSFileCoordinator', 'NSFilePresenter', 'isUbiquitousItem', 'NSUbiquitousKeyValueStore', 'ubiquitous file sync' - comprehensive file-based iCloud sync reference
Use when implementing in-app purchases, StoreKit 2, subscriptions, or transaction handling - testing-first workflow with .storekit configuration, StoreManager architecture, transaction verification, subscription management, and restore purchases for consumables, non-consumables, and auto-renewable subscriptions
Use when fixing or auditing ANY accessibility issue - VoiceOver, Dynamic Type, color contrast, touch targets, WCAG compliance, App Store accessibility review.
Use when implementing ANY Apple Intelligence or on-device AI feature. Covers Foundation Models, @Generable, LanguageModelSession, structured output, Tool protocol, iOS 26 AI integration.
Use when ANY iOS build fails, test crashes, Xcode misbehaves, or environment issue occurs before debugging code. Covers build failures, compilation errors, dependency conflicts, simulator problems, environment-first diagnostics.
Use when writing ANY code with async, actors, threads, or seeing ANY concurrency error. Covers Swift 6 concurrency, @MainActor, Sendable, data races, async/await patterns, performance optimization.
Use when working with ANY data persistence, database, axiom-storage, CloudKit, migration, or serialization. Covers SwiftData, Core Data, GRDB, SQLite, CloudKit sync, file storage, Codable, migrations.
Use when building ANY 2D or 3D game, game prototype, or interactive simulation with SpriteKit, SceneKit, or RealityKit. Covers scene graphs, ECS architecture, physics, actions, game loops, rendering, SwiftUI integration, SceneKit migration.
Use when working with ANY GPU rendering, Metal, OpenGL migration, shaders, 3D content, RealityKit, AR, or display performance. Covers Metal migration, shader conversion, RealityKit ECS, RealityView, variable refresh rate, ProMotion.
Use when integrating ANY iOS system feature - Siri, Shortcuts, Apple Intelligence, widgets, IAP, camera, photo library, photos picker, audio, axiom-haptics, axiom-localization, privacy, alarms. Covers App Intents, WidgetKit, StoreKit, AVFoundation, PHPicker, PhotosPicker, Core Haptics, App Shortcuts, Spotlight, AlarmKit.
Use when deploying ANY machine learning model on-device, converting models to CoreML, compressing models, or implementing speech-to-text. Covers CoreML conversion, MLTensor, model compression (quantization/palettization/pruning), stateful models, KV-cache, multi-function models, async prediction, SpeechAnalyzer, SpeechTranscriber.
Use when implementing or debugging ANY network connection, API call, or socket. Covers URLSession, Network.framework, NetworkConnection, deprecated APIs, connection diagnostics, structured concurrency networking.
Use when app feels slow, memory grows, battery drains, or diagnosing ANY performance issue. Covers memory leaks, profiling, Instruments workflows, retain cycles, performance optimization.
Use when writing ANY test, debugging flaky tests, making tests faster, or asking about Swift Testing vs XCTest. Covers unit tests, UI tests, fast tests without simulator, async testing, test architecture.
Use when building, fixing, or improving ANY iOS UI including SwiftUI, UIKit, layout, navigation, animations, design guidelines. Covers view updates, layout bugs, navigation issues, performance, architecture, Apple design compliance.
Use when implementing ANY computer vision feature - image analysis, object detection, pose detection, person segmentation, subject lifting, hand/body pose tracking.
Use when SecItem calls fail — errSecDuplicateItem from unexpected uniqueness, errSecItemNotFound despite item existing, errSecInteractionNotAllowed in background, keychain items disappearing after app update, access group entitlement errors, or Mac keychain shim issues. Covers systematic error diagnosis with decision trees.
Use when needing SecItem function signatures, keychain attribute constants, item class uniqueness constraints, accessibility level details, SecAccessControlCreateFlags, kSecReturn behavior per class, LAContext keychain integration, or OSStatus error codes. Covers complete keychain API surface.
Use when storing credentials, tokens, or secrets securely, debugging SecItem errors (errSecDuplicateItem, errSecItemNotFound, errSecInteractionNotAllowed), managing keychain access groups, or choosing accessibility classes. Covers SecItem API mental model, uniqueness constraints, data protection, biometric access control, sharing between apps, and Mac keychain differences.
Use when planning comprehensive Liquid Glass adoption across an app, auditing existing interfaces for Liquid Glass compatibility, implementing app icon updates, or understanding platform-specific Liquid Glass behavior - comprehensive reference guide covering all aspects of Liquid Glass adoption from WWDC 2025
Use when implementing Liquid Glass effects, reviewing UI for Liquid Glass adoption, debugging visual artifacts, optimizing performance, or requesting expert review of Liquid Glass implementation - provides comprehensive design principles, API patterns, and troubleshooting guidance from WWDC 2025. Includes design review pressure handling and professional push-back frameworks
Complete LLDB command reference — variable inspection, breakpoints, threads, expression evaluation, process control, memory commands, and .lldbinit customization
Use when ANY runtime debugging is needed — setting breakpoints, inspecting variables, evaluating expressions, analyzing threads, or reproducing crashes interactively with LLDB
Use when localizing apps, using String Catalogs, generating type-safe symbols (Xcode 26+), handling plurals, RTL layouts, locale-aware formatting, or migrating from .strings files - comprehensive i18n patterns for Xcode 15-26
MapKit troubleshooting — annotations not appearing, region jumping, clustering not working, search failures, overlay rendering issues, user location problems
MapKit API reference — SwiftUI Map, MKMapView, Marker, Annotation, MKLocalSearch, MKDirections, Look Around, MKMapSnapshotter, clustering, overlays, GeoToolbox PlaceDescriptor, geocoding
Use when implementing maps, annotations, search, directions, or debugging MapKit display/performance issues - SwiftUI Map, MKMapView, MKLocalSearch, clustering, Look Around
Use when you see memory warnings, 'retain cycle', app crashes from memory pressure, or when asking 'why is my app using so much memory', 'how do I find memory leaks', 'my deinit is never called', 'Instruments shows memory growth', 'app crashes after 10 minutes' - systematic memory leak detection and fixes for iOS/macOS
Use when ANY Metal porting issue occurs - black screen, rendering artifacts, shader errors, wrong colors, performance regressions, GPU crashes
Use when converting shaders or looking up API equivalents - GLSL to MSL, HLSL to MSL, GL/DirectX to Metal mappings, MTKView setup code
Use when porting OpenGL/DirectX to Metal - translation layer vs native rewrite decisions, migration planning, anti-patterns
MetricKit API reference for field diagnostics - MXMetricPayload, MXDiagnosticPayload, MXCallStackTree parsing, crash and hang collection
Reference — Comprehensive Network.framework guide covering NetworkConnection (iOS 26+), NWConnection (iOS 12-25), TLV framing, Coder protocol, NetworkListener, NetworkBrowser, Wi-Fi Aware discovery, and migration strategies
Use when debugging connection timeouts, TLS handshake failures, data not arriving, connection drops, performance issues, or proxy/VPN interference - systematic Network.framework diagnostics with production crisis defense
This skill should be used when working with NWConnection patterns for iOS 12-25, supporting apps that can't use async/await yet, or maintaining backward compatibility with completion handler networking.
Network framework migration guides. Use when migrating from BSD sockets to NWConnection, NWConnection to NetworkConnection (iOS 26+), or URLSession StreamTask to NetworkConnection.
Use when implementing Network.framework connections, debugging connection failures, migrating from sockets/URLSession streams, or adopting structured concurrency networking patterns - prevents deprecated API usage, reachability anti-patterns, and thread-safety violations with iOS 12-26+ APIs
CarPlay Now Playing integration patterns. Use when implementing CarPlay audio controls, CPNowPlayingTemplate customization, or debugging CarPlay-specific issues.
MusicKit Now Playing integration patterns. Use when playing Apple Music content with ApplicationMusicPlayer and understanding automatic vs manual Now Playing info updates.
Use when Now Playing metadata doesn't appear on Lock Screen/Control Center, remote commands (play/pause/skip) don't respond, artwork is missing/wrong/flickering, or playback state is out of sync - provides systematic diagnosis, correct patterns, and professional push-back for audio/video apps on iOS 18+
Use when debugging memory leaks from blocks, blocks assigned to self or properties, network callbacks, or crashes from deallocated objects - systematic weak-strong pattern diagnosis with mandatory diagnostic rules
Use when optimizing large value type performance, working with noncopyable types, reducing ARC traffic, or using InlineArray/Span for zero-copy memory access. Covers borrowing, consuming, inout modifiers, consume operator, ~Copyable types, InlineArray, Span, value generics.
Use when implementing passkey sign-in, replacing passwords with WebAuthn, configuring ASAuthorizationController, setting up AutoFill-assisted requests, adding automatic passkey upgrades, or migrating from password-based authentication. Covers passkey creation, assertion, cross-device sign-in, credential managers, and the Passwords app.
Use when app feels slow, memory grows over time, battery drains fast, or you want to profile proactively - decision trees to choose the right Instruments tool, deep workflows for Time Profiler/Allocations/Core Data, and pressure scenarios for misinterpreting results
Reference — PHPickerViewController, PHPickerConfiguration, PhotosPicker, PhotosPickerItem, Transferable, PHPhotoLibrary, PHAsset, PHAssetCreationRequest, PHFetchResult, PHAuthorizationStatus, limited library APIs
PHPicker, PhotosPicker, photo selection, limited library access, presentLimitedLibraryPicker, save to camera roll, PHPhotoLibrary, PHAssetCreationRequest, Transferable, PhotosPickerItem, photo permissions
Use when implementing privacy manifests, requesting permissions, App Tracking Transparency UX, or preparing Privacy Nutrition Labels - covers just-in-time permission requests, tracking domain management, and Required Reason APIs from WWDC 2023
Use when push notifications fail to arrive, token registration errors occur, notifications work in development but not production, silent push does not wake app, rich notification media is missing, or Live Activity stops updating via push. Covers APNs errors, environment mismatches, Focus mode filtering, service extension failures, FCM diagnostics.
Use when needing APNs HTTP/2 transport details, JWT authentication setup, payload key reference, UNUserNotificationCenter API, notification category/action registration, service extension lifecycle, local notification triggers, Live Activity push headers, or broadcast push format. Covers complete push notification API surface.
Use when implementing remote or local push notifications, requesting notification permission, managing APNs device tokens, adding notification actions/categories, building service extensions, or debugging push delivery failures. Covers APNs, FCM, Live Activity push transport, broadcast push, communication notifications, Focus interaction.
Use when RealityKit entities not visible, anchors not tracking, gestures not responding, performance drops, materials wrong, or multiplayer sync fails
Claude Skills — questions
Answers built from the skills we actually parsed.