iOS 27 Siri Extensions: What iOS Developers Should Build Before WWDC 2026

Apple is expected to announce iOS 27 at WWDC 2026 on June 8-12, and the biggest feature for iOS developers is the rumored Siri Extensions API. If the reporting is accurate (AppleInsider and MacRumors have both covered it), iOS 27 will finally let Siri hand off to third-party AI models like Claude, Gemini, Grok, and Perplexity, with indie apps sitting in the middle as the action-execution layer via App Intents. This post is the indie iOS developer playbook for preparing your app so you get a distribution lift on day one.

Short version: if your app has any natural voice- or command-shaped interactions, you need to ship robust App Intents before WWDC 2026. Apps with well-designed App Intents get automatically surfaced by Siri Extensions when it ships. Apps without have to scramble for months to catch up. Preparation window is now.

What Siri Extensions is expected to do

Based on AppleInsider's March 2026 reporting and MacRumors' April 19 WWDC graphic analysis, the Siri Extensions API has four components:

• User picks a preferred AI model in Settings. Default is Apple Intelligence (Foundation Models). Alternatives likely include Claude, Gemini, ChatGPT, Grok, Perplexity. Possibly opt-in per query.
• Siri hands the raw query to the chosen model. Siri itself handles routing, authentication, and UI. The third-party model returns structured intent.
• The model can call your app's App Intents. Instead of the model saying "To add a task, open your todo app and..." it calls theAddTaskIntent directly via App Intents and executes.
• Your app handles the action natively. The user sees your UI confirm. No model lock-in; your same App Intents work whether Siri is powered by Claude, Gemini, or Foundation Models.

Why this matters for indie developers

Three reasons Siri Extensions is potentially the biggest distribution lift since widgets:

• Zero new marketing cost. If your app has good App Intents, it shows up in every Siri interaction that matches. No ad spend, no App Store optimization, no content marketing. Pure distribution through Apple's own UI.
• Power users drive revenue. The users most likely to use Siri Extensions are the most engaged, highest-intent segment of the iPhone user base. They are also the users most likely to convert to paid tiers.
• Competitor lock-out via first-mover advantage. Apps that ship high-quality App Intents early become the default answer Siri picks for common tasks. Apps that ship later have to prove they are meaningfully better.

What App Intents actually are (quick refresher)

App Intents have existed since iOS 16 but most indie developers never shipped them seriously because the discovery surface was limited (Shortcuts app, Spotlight). Siri Extensions dramatically expands discovery.

An App Intent is a Swift struct that declares a named action your app can perform. It has typed parameters, a description, and a perform() method.

import AppIntents

struct AddTaskIntent: AppIntent {
    static let title: LocalizedStringResource = "Add a task"
    static let description = IntentDescription("Add a new task to your list")

    @Parameter(title: "Task title")
    var title: String

    @Parameter(title: "Due date")
    var dueDate: Date?

    func perform() async throws -> some IntentResult {
        let task = Task(title: title, dueDate: dueDate)
        try await TaskRepository.shared.save(task)
        return .result(value: task.id, dialog: "Added \(title) to your list")
    }
}

That one struct registers a named action with the system. Siri, Spotlight, Shortcuts, and (starting iOS 27) third-party AI models all discover and can invoke it.

The five App Intent categories indie apps should ship

Not every intent makes sense for every app. But every indie app should think through these five categories and ship at least two or three.

Rule of thumb: if your app has a "+" button anywhere, that's an Add intent. If your app has a search bar, that's a Query intent. If your app has a primary action, that is an Action intent.

Entities: the other half of a good App Intent

Parameters alone are not enough for a good Siri Extensions experience. Your app needs to expose its data as App Entities so Siri can reference specific items by name.

struct HabitEntity: AppEntity {
    static let typeDisplayRepresentation: TypeDisplayRepresentation = "Habit"
    static let defaultQuery = HabitQuery()

    let id: UUID
    let name: String
    let streak: Int

    var displayRepresentation: DisplayRepresentation {
        DisplayRepresentation(title: "\(name)", subtitle: "\(streak)-day streak")
    }
}

struct HabitQuery: EntityQuery {
    func entities(for identifiers: [HabitEntity.ID]) async throws -> [HabitEntity] {
        try await HabitRepository.shared.fetch(ids: identifiers)
    }

    func suggestedEntities() async throws -> [HabitEntity] {
        try await HabitRepository.shared.fetchAll()
    }
}

With HabitEntity, Siri can now understand "mark meditation complete" because it can resolve "meditation" to a specific HabitEntity via your HabitQuery, pass it to your CheckInIntent, and execute. Without entities, Siri cannot reference specific items by name.

Tips for writing intents that work well with LLM routing

Siri Extensions routes the query through a third-party model. LLMs prefer intents that look like good API designs. Five rules:

• Use natural English in title and description. "Add a task" not "addTaskV2". The LLM reads these strings to decide which intent to call.
• Keep parameter counts small. 1-4 parameters per intent. More than 4 and LLMs frequently guess wrong or ask too many follow-ups.
• Use typed parameters, not strings. Date, Duration, Measurement, and Entity types let the LLM infer correctly. Strings leave too much ambiguity.
• Provide concrete examples in the description. "Add a task to your todo list" is less useful than "Add a task, like 'call Mom at 5pm' or 'pick up groceries'."
• Return meaningful dialog. The dialog: parameter in IntentResult is what Siri reads back. Make it specific, not generic.

What to ship before WWDC 2026

A realistic preparation timeline for April-June 2026:

• Week of April 22-28. Audit your app and list every user action that would be a candidate for an App Intent. Pick 5-10.
• Week of April 29-May 5. Ship the 2-3 most-used intents. Focus on Add, Query, and Action types. Include App Entities where relevant.
• Week of May 6-19. Add 2-3 more intents. Ensure full Siri Shortcut testing on iPhone 16 Pro and iPad Pro M4.
• Week of May 20-June 7. Polish copy on intent titles, descriptions, and dialog responses. Test against the current Siri for regression.
• WWDC week June 8-12. Watch the keynote live. If Siri Extensions ships, update your App Intents for any new patterns announced.
• Post-WWDC. Ship a build targeting iOS 27 that leverages any new Extensions-specific APIs Apple ships.

Apps most likely to win with Siri Extensions

Testing your App Intents today

• Run the Shortcuts app on your iPhone. Your intents should appear under "All Shortcuts" in the app action picker.
• Test with Siri directly. Say "[App Name] add a task" to invoke your AddTask intent. Siri will fill parameters conversationally.
• Test entity resolution. Say "[App Name] mark meditation complete" and verify Siri resolves "meditation" to the right habit.
• Test parameter disambiguation. If you say an ambiguous parameter, Siri should ask a clarifying question, not guess.

What The Swift Kit ships

The Swift Kit includes example App Intents for common productivity patterns (AddItem, CompleteItem, QueryList) along with matching App Entities. When Siri Extensions ships at WWDC 2026, the starter's intents already match the shape the API is expected to favor. You adapt to your specific product, and you get the Siri lift on iOS 27 launch day.

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Final recommendation

If there is any reasonable chance Siri Extensions ships at WWDC 2026 (and multiple sources suggest there is a strong one), the opportunity cost of not preparing App Intents is high. Even if the API ships later, App Intents already help with Shortcuts, Spotlight, and Focus filters. Spending 10-20 hours between now and June 8 to ship 3-5 well-designed intents is one of the highest-leverage things you can do for your indie iOS app this quarter.