# Apple opens Siri AI to every app developer: how App Intents and SKILL.md skills work, and why you can't ship until spring

> With the 27.3 betas, Apple opened a Siri AI Developer Preview that lets any app expose actions, content and multi-step "skills" to its new assistant. You can build and test now. You can't ship to the App Store until spring, iPhone users in the EU can't use Siri AI yet, and server-side usage has daily limits Apple hasn't quantified.

Published Nov 4, 2026 by TechMeasured Staff · AI · Canonical: https://techmeasured.com/ai/apple-siri-ai-developer-preview-app-intents-skills-what-developers-need-to-know

**Apple** opened a **Siri AI Developer Preview** to all developers on November 3. With it, any app can make its actions and content available to the new Siri AI assistant that shipped with iOS 27. The preview arrives with the iOS, iPadOS, macOS and visionOS 27.3 betas. Apple's own apps already use it. Apple lists 15 of them, including Mail, Maps, Messages, Notes, Photos, Reminders and Safari.

Why it matters: this is how third-party apps get into Apple's agent. Users will be able to ask Siri AI in their own words to check a delivery, book a reservation or place an order (Apple's examples), and Siri carries out the steps using the app. For developers, the more important point is the timeline. You can build now, but your users won't see it for months.

## What you can expose

Apple's post describes three pieces, all built on **App Intents**:

- **Custom actions.** Developers can expose app actions as tools Siri can call. According to the developer documentation summarized by PPC Land and DEV Community, you mark an intent with `@AppIntent(.tool)`, which makes it conform to a new `ToolIntent` protocol. Siri uses each intent's title and description, and each parameter's, to decide what to call. Write them for a model to read, not for a settings screen.
- **Skills.** Apple says skills teach Siri AI how to combine several actions into one experience for complex requests.
- **Content.** Apple says any entity in the Spotlight semantic index can now be surfaced to Siri AI, not just the ones that fit an existing schema.

Exposure is opt-in, action by action. Siri can only reach what an app explicitly makes available.

## Skills are SKILL.md files

Both PPC Land and DEV Community report that Apple's app skills use a cut-down version of the open Agent Skills format (agentskills.io):

- Each app target has one skills bundle, with one folder per skill containing a single `SKILL.md`.
- Front matter is limited to `name` and `description`. The name is 1–64 lowercase letters, digits and hyphens, and it must match the folder name. The description is one line of up to 1,024 characters, and it is the only part Siri reads when deciding whether a skill applies.
- The body is free-form Markdown, capped at 10,000 characters. Scripts and reference files aren't allowed.
- Xcode validates and compiles the bundle at build time. If two skills share a name, which one the system uses is undefined.

Both write-ups also stress a caveat from Apple's docs: skills are guidance, not deterministic programs. Siri decides what to do in each conversation, so any action that needs protecting still needs checks in your code.

## How to test it today

- Install a 27.3 beta on a device that supports Apple Intelligence, set to a supported language. Siri AI currently supports English, French, Japanese, Korean, Portuguese and Spanish. Apple says Traditional Chinese, Norwegian, Turkish and Vietnamese are coming soon.
- According to the reports on Apple's docs, integrations work only in **development-signed builds** and for **internal TestFlight** testers. External TestFlight testers and App Store users get nothing for now.
- Skills can be verified only on a device, not in the Simulator.
- Xcode includes a **Siri Integration Advisor** that reviews App Intents code. A new **Siri Evaluations** framework, in beta, lets you script conversations and check which intents, entities and skills Siri chose. Responses can vary between runs, so repeat your test sets.
- Apple is holding Apple Intelligence Group Labs for Q&A with its engineers on November 4 (9–10 a.m. PT) and November 5 (6–7 p.m. PT).

## The catches

| Issue | What Apple says |
|---|---|
| Shipping | First integrations reach customers in a few months. App Store submission opens in the spring. No exact dates. |
| EU | Siri AI is unavailable in the EU on iOS, iPadOS and watchOS. Apple says it is "working constructively with the EU." |
| Age | Not available to users under 13 |
| Usage limits | Server-side features, including Siri AI, have daily limits that vary by feature, request complexity and system demand. Apple hasn't published the numbers. |
| Cost | Apple says expanded access to those server-side features will be offered for a fee later. No price yet. |
| Terms | Terms and usage policies for Siri AI experiences are still to come |
| Stability | The API and Siri's behavior may change during the preview |

PPC Land points out an open question Apple hasn't answered: whether requests that go through a third-party app's tools count against a user's daily allowance. It also notes that EU Mac and Vision Pro users have had Siri AI since September. For now, an iPhone integration simply can't reach iPhone users in the EU.

## What to do

If your app has clear, repeatable tasks like ordering, booking, tracking or searching your own content, start now. Mark those intents as tools, write descriptions that are precise and meant for a model, and draft one or two skills for your most common multi-step flows. The spring App Store opening gives you a few months to tune behavior with Siri Evaluations before users see it. Hold off on building a business model around Siri AI usage until Apple publishes its limits, fees and terms.


## Sources

1. [Apple Developer — Siri AI is now open to all developers](https://developer.apple.com/news/?id=gdk2umrf)
2. [PPC Land — Apple opens Siri AI to all developers, but apps can't ship it until spring](https://ppc.land/apple-opens-siri-ai-to-all-developers-but-apps-cant-ship-it-until-spring/)
3. [The Next Web — Apple opens Siri AI to all developers, with daily limits and a fee](https://thenextweb.com/news/apple-siri-ai-developer-preview-app-intents-usage-limits-fee)
4. [DEV Community (Gabriel Anhaia) — Siri AI opens to every app in the iOS 27.3 beta. Its app skills are SKILL.md files](https://dev.to/gabrielanhaia/siri-ai-opens-to-every-app-in-the-ios-273-beta-its-app-skills-are-skillmd-files-4dc5)