Book Tracker: Using Evaluations to evaluate an intelligent feature

At a glance

Project structure

Source bundle/
├── DatasetExtractor/
│   └── main.swift
├── BookTracker/
│   ├── BookTrackerApp.swift
│   ├── Services/
│   │   ├── BookSearchTools.swift
│   │   └── BookTaggingService.swift
│   ├── Views/
│   │   ├── BookDetailView.swift
│   │   ├── LibraryView.swift
│   │   ├── SearchView.swift
│   │   └── AddBookView.swift
│   └── ContentView.swift
├── BookSampleGenerator/
│   └── main.swift
├── HillClimbingEvaluations/
│   └── ModelJudgeAlignmentEvaluation.swift
└── BookTrackerEvaluations/
    └── SearchBooks.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 3 project/configuration file(s) and 47 source declaration(s).

Overall architecture

flowchart LR
    N1["BookTrackerApp"]
    N2["ContentView"]
    N3["BookTaggingService"]
    N4["Evaluations APIs"]
    N1 --> N2
    N2 --> N3
    N3 --> N4

Reference code

BookTracker/BookTrackerApp.swift:12 — architecture anchor

@main
struct BookTrackerApp: App {
    let container: ModelContainer = {
        do {
            let container = try ModelContainer(for: Book.self)
            addSampleBooks(in: container.mainContext)
            return container
        } catch {
            fatalError("Failed to create ModelContainer: \(error)")
        }
    }()

    var body: some Scene {
        WindowGroup {
            ContentView()
        }
        .modelContainer(container)
    }
}

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 Evaluations.

Ownership and state

classDiagram
    BookTrackerApp o-- ModelContainer : container
    BookSearchCollector *-- Array : orderedIDs
    BookSearchCollector *-- Set : seen
    BookSnapshot *-- String : id

Ownership evidence

BookTracker/BookTrackerApp.swift:14 — stored dependency or nearest verified ownership anchor

    let container: ModelContainer = {
        // ...
            let container = try ModelContainer(for: Book.self)
        // ...
    }()

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

BookSampleGenerator/main.swift:67 — representative execution boundary

for try await sample in generator.run() {
    // Access results during iteration.
    expandedDataset.append(sample)
}

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

BookTracker/BookTrackerApp.swift:13 — representative type boundary

@main
struct BookTrackerApp: App {
    // ...
            let container = try ModelContainer(for: Book.self)
    // ...
}

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

Access control

Reference code

BookTracker/BookTrackerApp.swift:34 — representative boundary

@MainActor
private func addSampleBooks(in context: ModelContext) {
    let existing = (try? context.fetch(FetchDescriptor<Book>())) ?? []
    // ...
}

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: BookTrackerApp; Command: DatasetExtractorCommand; Service: BookTaggingService; View: AddBookView, BookDetailView, BookTagsView, ContentView, LibraryView.
• Protocols: no local protocol declaration in the scanned source.
• Methods: run, extractPairs, extractPrompt, resolvedOutputURL, defaultOutputURL, addSampleBooks, add, call.
• Files: BookTracker/BookTrackerApp.swift, BookTracker/Views/BookDetailView.swift, BookTracker/Services/BookTaggingService.swift, BookTracker/ContentView.swift, BookTracker/Views/LibraryView.swift, BookTracker/Views/SearchView.swift.

Architecture takeaways

• BookTrackerApp is the main source-visible entry or composition anchor for this sample.
• Framework work reaches SwiftUI, FoundationModels, SwiftData, Evaluations 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