{"slug": "apple-opens-siri-ai-to-every-app-ios-27-3-developer-guide", "title": "Apple Opens Siri AI to Every App: iOS 27.3 Developer Guide", "summary": "Apple opened Siri AI to all third-party developers on November 3 through the iOS 27.3 beta, letting any app expose actions to Siri by adding the single Swift macro @AppIntent(.tool) to an existing AppIntent struct, which makes it conform to the new ToolIntent protocol. Apps can ship to end users only when App Store submissions open in Spring 2027, and Apple says the API can still change; the company has not published usage terms for Siri AI experiences and has signaled that heavier cloud-based Siri use will eventually require paid expanded access. Apple deprecated SiriKit at WWDC 2026, and since iOS 27 shipped to users in September, apps still relying on SiriKit are already invisible to Siri AI on users' iPhones.", "body_md": "Apple opened Siri AI to all third-party developers on November 3 via the iOS 27.3 beta. A single Swift macro — `@AppIntent(.tool)` — is now all it takes to turn any existing app action into a tool Siri can call by name. Apps cannot reach end-users until spring, but the developers who start building today will ship first. The ones who wait will be scrambling when App Store submissions open.\n\n## One Macro, Instant Siri Tool\n\nThe core change is surgical. Add `@AppIntent(.tool)` to any existing `AppIntent` struct and it conforms to the new `ToolIntent` protocol — Apple’s signal that Siri can now invoke it on a user’s behalf.\n\n``` js\n@AppIntent(.tool)\nstruct AddToCart: AppIntent {\n    static var title: LocalizedStringResource = \"Add item to cart\"\n    static var description = IntentDescription(\n        \"Adds the specified item to the user’s shopping cart.\"\n    )\n\n    @Parameter(title: \"Item Name\", description: \"The name of the product to add\")\n    var itemName: String\n\n    func perform() async throws -> some IntentResult { ... }\n}\n```\n\nTwo details matter more than the macro itself. First, your intent’s `title` and `description` are what Siri reads to understand what the action does — treat them as documentation, not boilerplate. Second, every `@Parameter` needs its own title and description. Siri uses them to map natural language to the correct parameter. Skip them and Siri will guess wrong.\n\nTwo cases don’t need the annotation: intents already conforming to a supported primary domain schema (such as Messages’ `sendMessage`), and intents with no custom action in `perform()` like widget configuration intents. Everything else needs the macro.\n\n## SKILL.md: The Detail Nobody Expected\n\nThe more interesting discovery is how Apple handles multi-step workflows. Apps can ship a `Skills.skillsbundle` inside their app target — a bundle Xcode validates and compiles — and each skill inside it is a folder containing a `SKILL.md` file.\n\nYes, a Markdown file. If you’ve used Claude Code’s `CLAUDE.md` or any [agent skill format](https://dev.to/gabrielanhaia/siri-ai-opens-to-every-app-in-the-ios-273-beta-its-app-skills-are-skillmd-files-4dc5), the pattern is immediately familiar. Apple’s version is minimal: only `name` and `description` in the frontmatter, with the body used to describe how Siri should chain your tool intents together.\n\n```\n---\nname: Shopping Workflow\ndescription: Handles product search, cart management, and checkout\n---\n\nUse AddToCart when the user wants to buy a specific item.\nUse CheckInventory before adding to confirm the item is available.\nUse StartCheckout only after the user has confirmed the cart contents.\n```\n\nApple adopting the same markdown-based skill format emerging across the agentic ecosystem suggests these patterns are converging faster than expected. Your SKILL.md is the difference between Siri completing a three-step workflow and Siri stopping after the first action to ask for clarification. [Apple’s App Skills documentation](https://developer.apple.com/documentation/appintents/orchestrating-complex-actions-with-app-skills) covers the full spec.\n\n## The Timeline: Build Now, Ship in Spring\n\nThe preview is open now for development-signed builds and internal TestFlight. App Store submissions open in Spring 2027. The API can still change — Apple says so explicitly — so build and test, but don’t hardcode anything that isn’t documented as stable.\n\nTwo additional caveats worth noting: usage terms for Siri AI experiences haven’t been published yet, and Apple has signaled that heavier cloud-based Siri use will eventually require paid expanded access. Plan for that before building a workflow that makes dozens of Siri calls per session.\n\n## SiriKit Is Already Gone on iOS 27\n\nThis is the part many developers have missed. Apple deprecated SiriKit at WWDC 2026. iOS 27 shipped to users in September. If your app uses SiriKit, it is already invisible to Siri AI on the iPhones in your users’ pockets right now.\n\nSiriKit code still compiles in Xcode 27 — it emits deprecation warnings and does nothing on iOS 27 devices. You need a dual-framework strategy: keep SiriKit for the iOS 26 install base and add App Intents for iOS 27 and beyond. For most apps using one or two SiriKit domains, the migration is measured in days. Xcode provides automatic conversion tooling. [SoftwareSeni has a solid breakdown of what the deprecation means in practice.](https://www.softwareseni.com/why-apple-is-retiring-sirikit-and-what-app-intents-means-for-developers/)\n\n## Apple Is Behind, but the API Is Clean\n\nTo be honest about where Apple stands: Google’s Gemini on Galaxy S26 already ships multi-step app actions to end-users. Windows Copilot has VS Code and GitHub Copilot integration Apple can’t match in Xcode yet. Apple is playing catch-up at the OS-level AI layer, and it’s doing so while outsourcing its AI to Google’s Gemini under a deal revealed at WWDC 2026.\n\nWhat Apple has that competitors don’t: a billion iPhones where Siri is the default assistant, system-level access to Mail, Messages, Calendar, and Photos, and genuine on-device privacy. The App Intents API design is also cleaner than competing approaches — a struct-based intent model with explicit descriptions is more auditable than loose natural language tool definitions.\n\n## What to Do This Week\n\n- Install iOS 27.3 beta on a test device\n- Audit existing SiriKit code and begin the migration\n- Add `@AppIntent(.tool)` to your top three to five user-facing actions\n- Write descriptions for every parameter — treat them like API docs\n- Create a `SKILL.md` for any workflow involving more than one action\n- Watch [WWDC 2026 session 240](https://developer.apple.com/videos/play/wwdc2026/240/) and session 295\n\nSpring is closer than it looks.", "url": "https://wpnews.pro/news/apple-opens-siri-ai-to-every-app-ios-27-3-developer-guide", "canonical_source": "https://byteiota.com/apple-opens-siri-ai-every-app-ios-273-developer-guide/", "published_at": "2026-11-04 11:06:48+00:00", "updated_at": "2026-11-04 11:27:27.484319+00:00", "lang": "en", "topics": ["ai-agents", "ai-products", "developer-tools", "large-language-models"], "entities": ["Apple", "Siri", "iOS 27.3", "SiriKit", "ToolIntent", "AppIntent", "WWDC 2026"], "also_reported_by": [], "alternates": {"html": "https://wpnews.pro/news/apple-opens-siri-ai-to-every-app-ios-27-3-developer-guide", "markdown": "https://wpnews.pro/news/apple-opens-siri-ai-to-every-app-ios-27-3-developer-guide.md", "text": "https://wpnews.pro/news/apple-opens-siri-ai-to-every-app-ios-27-3-developer-guide.txt", "jsonld": "https://wpnews.pro/news/apple-opens-siri-ai-to-every-app-ios-27-3-developer-guide.jsonld"}}