feature

name: feature description: Creates a new feature module with minimal viable structure. Use when bootstrapping a new feature from scratch, scaffolding the Tuist module, Container, Feature entry point, DeepLinkHandler, and initial screen with placeholder Text view. Includes all unit tests, mocks, stubs, and app integration. For adding domain/data layers afterward, use /datasource, /repository, /usecase. For enhancing views, use /view, /viewmodel, /navigator.

Skill: Feature

Create a new feature module with the minimum viable structure: Tuist module, Feature entry point, Container, DeepLinkHandler, and one screen with placeholder Text. Integrates into the app.

Parameters

Gather from user before starting:

Derived: module name = Challenge{Feature}, event prefix = snake_case of Screen.

File Structure

Features/{Feature}/
├── Sources/
│   ├── {Feature}Feature.swift
│   ├── {Feature}Container.swift
│   └── Presentation/
│       ├── Navigation/
│       │   ├── {Feature}IncomingNavigation.swift
│       │   └── {Feature}DeepLinkHandler.swift
│       └── {Screen}/
│           ├── Navigator/
│           │   ├── {Screen}NavigatorContract.swift
│           │   └── {Screen}Navigator.swift
│           ├── Tracker/
│           │   ├── {Screen}TrackerContract.swift
│           │   ├── {Screen}Tracker.swift
│           │   └── {Screen}Event.swift
│           ├── ViewModels/
│           │   ├── {Screen}ViewModelContract.swift
│           │   └── {Screen}ViewModel.swift
│           └── Views/
│               └── {Screen}View.swift
└── Tests/
    ├── Unit/
    │   ├── Feature/
    │   │   └── {Feature}FeatureTests.swift
    │   └── Presentation/
    │       ├── Navigation/
    │       │   └── {Feature}DeepLinkHandlerTests.swift
    │       └── {Screen}/
    │           ├── Navigator/
    │           │   └── {Screen}NavigatorTests.swift
    │           ├── Tracker/
    │           │   ├── {Screen}TrackerTests.swift
    │           │   └── {Screen}EventTests.swift
    │           └── ViewModels/
    │               └── {Screen}ViewModelTests.swift
    └── Shared/
        ├── Mocks/
        │   ├── {Screen}NavigatorMock.swift
        │   └── {Screen}TrackerMock.swift
        └── Stubs/
            └── {Screen}ViewModelStub.swift

Conventions

• No @Observable on minimal ViewModels (no observable state). Only add when ViewModel has private(set) var.
• Container factory methods return some View (not some ViewModelContract). The Container creates both the ViewModel and wraps it in the View. Features call container.make{Screen}View(navigator:) and wrap in AnyView.
• No any keyword on internal protocol types. Only on public protocols from other modules (e.g., any TrackerContract in Container).
• No imports in ViewModel when all types are internal to the module.
• Deep link paths are scoped per host — /list under episode host is independent from /list under character host.
• Deep links use path-based URLs — parameters are embedded in the path (e.g., challenge://character/detail/42), never as query items (?id=42). Use url.pathComponents for parsing.
• Tuist module uses \(appName) string interpolation for target names.
• Features always receive HTTPClientContract as their network dependency — never specific clients like GraphQLClientContract. The Container is responsible for creating specific clients (e.g., GraphQLClient) internally from the HTTPClientContract. This keeps features decoupled from transport details.
• Features that don't need networking only receive tracker: any TrackerContract.
• Features that need networking receive httpClient: any HTTPClientContract, tracker: any TrackerContract.

Workflow

Step 1: Tuist Module

Create Tuist/ProjectDescriptionHelpers/Modules/{Feature}Module.swift:

import ProjectDescription

public let {feature}Module = Module.create(directory: "Features/{Feature}")

Register the module in Modules.swift — Add {feature}Module to the Modules.all array. This single registration automatically includes the module's package in the root project and its test target in the Dev scheme (Framework: via testableTargets, SPM: via Challenge.xctestplan).

Step 2: Source Files

Create all source files from sources.md.

Order: IncomingNavigation → DeepLinkHandler → NavigatorContract → Navigator → TrackerContract → Tracker → Event → ViewModelContract → ViewModel → View → Container → Feature.

Step 3: Test Files

Create all test files from tests.md.

Order: Mocks → Stubs → Unit tests.

Step 4: App Integration

Wire the feature into the app — 4 files to modify:

Tuist/ProjectDescriptionHelpers/Modules/AppKitModule.swift — Add dependency:

{feature}Module.targetDependency,

AppKit/Sources/AppContainer.swift — Three changes:

1. Add import: import Challenge{Feature}
2. Add property: private let {feature}Feature: {Feature}Feature
3. Initialize in init:
   • Without networking: {feature}Feature = {Feature}Feature(tracker: self.tracker)
   • With networking: {feature}Feature = {Feature}Feature(httpClient: self.httpClient, tracker: self.tracker)
4. Add to features array

AppKit/Tests/Unit/AppContainerTests.swift — No changes needed (features is private, tested indirectly).

Step 5: Verify

xcodebuild test \
  -workspace Challenge.xcworkspace \
  -scheme "Challenge (Dev)" \
  -destination 'platform=iOS Simulator,name=iPhone 17 Pro,OS=26.1'

Extending the Feature