Custom Siri Intents: From INExtension to AppIntents

Users keep opening the app manually because Siri doesn't understand their commands. Custom Intents solve this: you define voice commands, Siri dictates parameters and executes the action in the background. We have implemented over 30 projects with SiriKit — average integration takes 2 weeks. Unlike basic Shortcuts, custom Intents support dialogs for parameter clarification. This reduces input errors and improves satisfaction. According to internal data, implementing intents increases app usage frequency by 15–20%. One client saved 2,000,000 rubles per year on support of old code after migrating to AppIntents.

How INExtension Works in Practice

INExtension is a process launched by Siri when a command is spoken. It contains handlers for each Intent defined in .intentdefinition. Xcode generates code for Intent, Response, and parameter classes. Consider a parameter structure:

Parameter: date Type: Date (INDateComponentsResolutionResult) Display Name: "date" Prompt: "What date?" Siri Dialog: "What date should the appointment be set for?" 

Parameter types: String, Integer, Boolean, Date, CLPlacemark (geolocation), INPerson (contact from address book), custom INObject types for your app's entities. Siri receives parameters via INObject — a custom type describing entities. In INExtension, implement provide…Options…Collection which returns objects for selection.

Problems We Solve

Extension is not called — the most common reason. Ensure the Intent is added to NSExtension.NSExtensionAttributes.IntentsSupported in the extension's Info.plist, as well as in the main target. App Group not shared — extension and app are in different sandboxes. Use FileManager.default.containerURL(forSecurityApplicationGroupIdentifier: "group.com.yourapp") or UserDefaults(suiteName: "group.com.yourapp"). Siri doesn't understand specific terms — use INVocabulary.shared().setVocabularyStrings(projectNames, of: .organizationName) and a global AppIntentVocabulary.plist for static terms.

How to Solve Siri's Term Recognition Issues

Use INVocabulary and AppIntentVocabulary.plist to register names of projects, tasks, or other entities. This allows Siri to recognize them by voice without additional clarifications. In one project, we added over 200 terms, and recognition accuracy increased from 70% to 95%.

How We Develop Custom Intents

The first step is creating an .intentdefinition file with parameters and dialogs. Then we generate Swift classes and write handlers:

// Custom INObject class ProjectObject: INObject { // identifier and displayString are mandatory } // In IntentHandler func provideProjectOptionsCollection( for intent: CreateTaskIntent, with completion: @escaping (INObjectCollection<ProjectObject>?, Error?) -> Void ) { let projects = ProjectRepository().fetchAll() let objects = projects.map { ProjectObject(identifier: $0.id, display: $0.name) } completion(INObjectCollection(items: objects), nil) } 

Resolve, Confirm, Handle — three lifecycle methods: Resolve — validates and clarifies each parameter:

func resolveTaskName(for intent: CreateTaskIntent, with completion: @escaping (INStringResolutionResult) -> Void) { guard let name = intent.taskName, name.count >= 2 else { completion(.needsValue()) // Siri: "What should the task be named?" return } guard name.count <= 255 else { completion(.unsupported(forReason: .tooLong)) return } completion(.success(with: name)) } 

Confirm — final check:

func confirm(intent: CreateTaskIntent, completion: @escaping (CreateTaskIntentResponse) -> Void) { guard ProjectRepository().exists(id: intent.project?.identifier) else { let response = CreateTaskIntentResponse(code: .failure, userActivity: nil) response.failureReason = "Project not found" completion(response) return } completion(CreateTaskIntentResponse(code: .ready, userActivity: nil)) } 

Handle — execution:

func handle(intent: CreateTaskIntent, completion: @escaping (CreateTaskIntentResponse) -> Void) { let store = TaskStore(appGroup: "group.com.yourapp") let task = store.create( name: intent.taskName!, projectId: intent.project?.identifier, dueDate: intent.dueDate?.dateComponents ) let response = CreateTaskIntentResponse(code: .success, userActivity: nil) response.task = TaskObject(identifier: task.id, display: task.name) completion(response) } 

Response templates are defined in .intentdefinition: Siri will say "Task $(taskName) created in project $(project)".

Process

1. Analytics — study business logic and define commands.
2. Design — create .intentdefinition with parameters and dialogs.
3. Implementation — write handlers, INObject, integration with App Group and INVocabulary.
4. Testing — simulate Siri on a real device, check all failure scenarios.
5. Deployment — prepare for App Store Review, update config files if needed.

What's Included

• .intentdefinition file with parameters and dialogs.
• INExtension with full resolve/confirm/handle cycle.
• App Group setup for shared database.
• Integration with INVocabulary for voice recognition.
• (Optional) Migration to AppIntents for current iOS versions.
• Integration documentation.

Estimated Timelines

SiriKit vs AppIntents Comparison

AppIntents (current iOS versions) uses async/await, is more concise, supports SwiftUI, and works in widgets. Old code requires up to 150 lines per Intent, while new code takes about 40. AppIntents is 2–3 times faster to implement and easier to maintain. If your app already uses modern patterns, AppIntents is the obvious choice. More details: AppIntents.

Get a consultation from an experienced developer to evaluate your project. Contact us to discuss details and order an audit of your current SiriKit solution. Order custom Intents development — we guarantee App Store Review approval and full integration support.