Adding intelligent app features with generative models

At a glance

Project structure

Source bundle/
└── FoundationModelsTripPlanner/
    └── FoundationModelsTripPlanner/
        ├── FoundationModelsTripPlannerApp.swift
        ├── Views/
        │   ├── Itinerary/
        │   │   ├── Effects.swift
        │   │   ├── ItineraryView.swift
        │   │   ├── LandmarkTripView.swift
        │   │   ├── LandmarkDescriptionView.swift
        │   │   ├── ItineraryPlanningView.swift
        │   │   ├── MessageView.swift
        │   │   └── TripPlanningView.swift
        │   └── Landmarks/
        │       ├── LandmarkDetailMapView.swift
        │       └── LandmarkFeaturedItemView.swift
        ├── Model/
        │   └── Itinerary/
        │       └── Itinerary.swift
        └── Utils.swift

Structure observations

• Architecturally prominent files are ranked from entry points and role-named declarations; resource-only paths are omitted.
• Primary languages: Swift.
• The verified tree contains 5 project/configuration file(s) and 42 source declaration(s).

Overall architecture

flowchart LR
    N1["FoundationModelsTripPlannerApp"]
    N2["LandmarksView"]
    N3["FoundationModels APIs"]
    N1 --> N2
    N2 --> N3

Reference code

FoundationModelsTripPlanner/FoundationModelsTripPlanner/FoundationModelsTripPlannerApp.swift:10 — architecture anchor

@main
struct FoundationModelsTripPlannerApp: App {
    private var modelData = ModelData.shared

    var body: some Scene {
        WindowGroup {
            LandmarksView()
                .environment(modelData)
        }
    }
}

Interpretation

The arrows summarize the source-visible entry, role-named types or folders, and framework direction; when nodes come from structural folders, the sequence is a high-level interpretation rather than proof that every adjacent node calls the next. Ownership is claimed only where the next section cites a stored property or assignment. The diagram is intentionally limited to the dominant path into Foundation Models.

Ownership and state

classDiagram
    HeaderStyle o-- Landmark : landmark
    ActivityIcon *-- String : symbolName
    ActivityIcon *-- CGFloat : iconSize
    ItineraryView o-- Landmark : landmark

Ownership evidence

FoundationModelsTripPlanner/FoundationModelsTripPlanner/Views/Itinerary/Effects.swift:11 — stored dependency or nearest verified ownership anchor

struct HeaderStyle: ViewModifier {
    let landmark: Landmark
    // ...
}

Composition arrows indicate a source-visible construction expression or locally owned value state; aggregation means the owner stores or receives a dependency without proving exclusive lifetime ownership.

Concurrency, scheduling, and thread safety

Evidence limit: actor isolation, async/await, or Task creation does not by itself prove background-thread execution; Sendable conformance alone does not prove thread-safe mutation.

@MainActor/MainActor.run, DispatchQueue.main, and RunLoop.main are reported as distinct isolation, queue, and event-loop mechanisms. A plain Task is kept separate from Task.detached; neither is labeled as a background thread.

Reference code

FoundationModelsTripPlanner/FoundationModelsTripPlanner/Model/Itinerary/FindPointsOfInterestTool.swift:18 — representative execution boundary

@Observable
final class FindPointsOfInterestTool: Tool {
    // ...
    @MainActor var lookupHistory: [Lookup] = []
    // ...
}

State propagation, frameworks, and dependencies

Evidence limit: an import proves a source-level compilation dependency at the cited line; it does not prove runtime use, architectural adoption, or whether a Swift package is a direct application dependency.

receive(on:) describes downstream delivery scheduling, while subscribe(on:) describes upstream subscription/request/cancel scheduling. An import Combine alone establishes neither behavior nor a Store, reducer, Redux, or other application architecture.

Class and protocol design

FoundationModelsTripPlanner/FoundationModelsTripPlanner/FoundationModelsTripPlannerApp.swift:11 — representative type boundary

@main
struct FoundationModelsTripPlannerApp: App {
    private var modelData = ModelData.shared
    // ...
}

No local protocol conformance is claimed as protocol-oriented design; external framework conformances are listed only as dependencies.

Access control

Reference code

FoundationModelsTripPlanner/FoundationModelsTripPlanner/FoundationModelsTripPlannerApp.swift:12 — representative boundary

@main
struct FoundationModelsTripPlannerApp: App {
    private var modelData = ModelData.shared
    // ...
}

Swift declarations without a modifier are internal; explicit private, fileprivate, private(set), public, or open entries above are interpreted by language semantics. Objective-C/C samples instead rely on header and implementation boundaries, which are not equivalent to Swift lexical privacy.

Logic ownership and placement

Design patterns

Naming conventions

• Types: App: FoundationModelsTripPlannerApp; View: DayView, ItineraryPlanningView, ItineraryView, LandmarkDescriptionView, LandmarkDetailMapView.
• Protocols: no local protocol declaration in the scanned source.
• Methods: body, rationaleStyle, itineraryStyle, card, tagStyle, blurredBackground, headerStyle, requestItinerary.
• Files: FoundationModelsTripPlanner/FoundationModelsTripPlanner/FoundationModelsTripPlannerApp.swift, FoundationModelsTripPlanner/FoundationModelsTripPlanner/Views/Itinerary/ItineraryView.swift, FoundationModelsTripPlanner/FoundationModelsTripPlanner/Views/Itinerary/LandmarkTripView.swift, FoundationModelsTripPlanner/FoundationModelsTripPlanner/Views/Itinerary/LandmarkDescriptionView.swift, FoundationModelsTripPlanner/FoundationModelsTripPlanner/Model/Itinerary/Itinerary.swift, FoundationModelsTripPlanner/FoundationModelsTripPlanner/Views/Itinerary/ItineraryPlanningView.swift.

Architecture takeaways

• FoundationModelsTripPlannerApp is the main source-visible entry or composition anchor for this sample.
• Framework work reaches SwiftUI, FoundationModels, MapKit, WeatherKit through a deliberately small high-level chain; the detailed API graph remains inside the cited implementation files.
• Stored-property evidence identifies lifecycle collaboration; it does not by itself prove exclusive object ownership.
• Access-control conclusions separate verified language visibility from the likely design rationale.
• The source does not justify labeling the design protocol-oriented.

Source map

• Official Apple documentation