Sample CodeiOS, iPadOS, Mac Catalyst, macOS, visionOSReviewed 2026-07-21View on Apple Developer

Adding intelligent app features with generative models

At a glance

Item Summary
Purpose Build robust apps with guided generation and tool calling by adopting the Foundation Models framework.
App architecture A Swift sample with the source-visible chain FoundationModelsTripPlannerAppLandmarksViewFoundationModels APIs.
Main patterns Actor-isolated state
Project style 22 scanned source file(s) across Swift, organized around ranked entry, type, and file boundaries.

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

Reference code

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

@main
struct FoundationModelsTripPlannerApp: App {
    // ...
}

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

Ownership evidence

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

struct HeaderStyle: ViewModifier {
    let landmark: Landmark
    // ...
}
Owner Object or state Relationship Mutation authority
HeaderStyle Landmark (landmark) stores or receives Initialized by the owner; the binding is immutable
ActivityIcon String (symbolName) owns value state Initialized by the owner; the binding is immutable
ActivityIcon CGFloat (iconSize) owns value state App/module collaborators
ItineraryView Landmark (landmark) stores or receives Initialized by the owner; the binding is immutable

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.

Class and protocol design

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

struct FoundationModelsTripPlannerApp: App {
    // ...
}
Type Responsibility Depends on or conforms to
FoundationModelsTripPlannerApp Application entry and top-level composition App
ItineraryView User-interface presentation and input forwarding View
DayView User-interface presentation and input forwarding View
LandmarkTripView User-interface presentation and input forwarding View
LandmarkDescriptionView User-interface presentation and input forwarding View
ItineraryPlanningView User-interface presentation and input forwarding View
MessageView User-interface presentation and input forwarding View
TripPlanningView User-interface presentation and input forwarding View
LandmarkDetailMapView User-interface presentation and input forwarding View
LandmarkFeaturedItemView User-interface presentation and input forwarding View

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

Access control

Symbol Access Verified effect Likely rationale
modelData (FoundationModelsTripPlanner/FoundationModelsTripPlanner/FoundationModelsTripPlannerApp.swift:12) private Use is restricted to the lexical declaration and same-file extensions allowed by Swift. Inference: keep state mutation or dependency lifetime inside the owning implementation.
mapItems (FoundationModelsTripPlanner/FoundationModelsTripPlanner/Model/Itinerary/FindPointsOfInterestTool.swift:55) private Use is restricted to the lexical declaration and same-file extensions allowed by Swift. Inference: hide an implementation step that is not part of the collaboration surface.
itinerary (FoundationModelsTripPlanner/FoundationModelsTripPlanner/Model/Itinerary/ItineraryPlanner.swift:14) private(set) Read access follows the declaration; writes remain in the private scope. Inference: allow observation while reserving invariant-changing writes for the owner.
pointOfInterestTool (FoundationModelsTripPlanner/FoundationModelsTripPlanner/Model/Itinerary/ItineraryPlanner.swift:15) private(set) Read access follows the declaration; writes remain in the private scope. Inference: allow observation while reserving invariant-changing writes for the owner.

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

Logic Owning type or file Placement rationale
Application entry and top-level composition FoundationModelsTripPlannerApp The source’s App suffix makes this role explicit.
User-interface presentation and input forwarding DayView, ItineraryPlanningView, ItineraryView, LandmarkDescriptionView The source’s View suffix makes this role explicit.

Design patterns

Pattern Source evidence Purpose or tradeoff
Actor-isolated state FoundationModelsTripPlanner/FoundationModelsTripPlanner/Model/Itinerary/FindPointsOfInterestTool.swift:18 Actor annotations make the concurrency ownership boundary explicit.

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

Source file Relevant symbols
FoundationModelsTripPlanner/FoundationModelsTripPlanner/FoundationModelsTripPlannerApp.swift FoundationModelsTripPlannerApp
FoundationModelsTripPlanner/FoundationModelsTripPlanner/Views/Itinerary/Effects.swift HeaderStyle, CardModifier, TagStyleModifier, RationaleModifier, ItineraryModifier, BlurredBackgroundModifier, ActivityIcon
FoundationModelsTripPlanner/FoundationModelsTripPlanner/Views/Itinerary/ItineraryView.swift ItineraryView, DayView, ActivityList
FoundationModelsTripPlanner/FoundationModelsTripPlanner/Views/Itinerary/LandmarkTripView.swift LandmarkTripView, ItineraryButton, ItineraryHeader
FoundationModelsTripPlanner/FoundationModelsTripPlanner/Views/Itinerary/LandmarkDescriptionView.swift TaggingResponse, LandmarkDescriptionView
FoundationModelsTripPlanner/FoundationModelsTripPlanner/Model/Itinerary/Itinerary.swift Itinerary, DayPlan, Activity, Kind
FoundationModelsTripPlanner/FoundationModelsTripPlanner/Utils.swift Logging, Padding, ReadabilityRoundedRectangle, Lookup
FoundationModelsTripPlanner/FoundationModelsTripPlanner/Views/Itinerary/ItineraryPlanningView.swift ItineraryPlanningView
FoundationModelsTripPlanner/FoundationModelsTripPlanner/Views/Itinerary/MessageView.swift MessageView
FoundationModelsTripPlanner/FoundationModelsTripPlanner/Views/Itinerary/TripPlanningView.swift TripPlanningView