Apple's Siri AI Developer Preview Lets Apps Add Custom Intents and Markdown Skills; It Is Testable Only in Developer Builds and Internal TestFlight

Overview

Apple said in a developer news post dated November 3, 2026 that, starting that day, the iOS 27.3, iPadOS 27.3, macOS 27.3 and visionOS 27.3 betas include a Developer Preview that “enables any developer to integrate their app with Siri AI”. Apps bring content and actions to Siri AI through App Intents, and Apple also introduced skills that teach Siri AI how to combine several actions into one experience, according to the same post.

Apple’s documentation lists two ways to test the preview: build with Xcode, sign with a development profile and run on a supported device, or make a build available to internal testers in TestFlight. The page says the preview is not available to external TestFlight testers or to versions published on the App Store. InfoQ, reporting on November 13, 2026, summarises this as access “restricted to developer builds and internal TestFlight testers”. Apple’s documentation page also says that during the preview “the App Intents API and Siri functionality may change”. The documentation pages carry no date; the Herald read them on November 14, 2026.

What an app can expose

Apple’s documentation describes the preview as covering custom actions and information, not only functionality and data that fits the system-defined app schema domains (Apple documentation). 9to5Mac, an Apple-focused outlet, wrote that “the first versions of Siri AI were limited to a much smaller set of supported schemas” (9to5Mac). That is 9to5Mac’s characterisation, not Apple’s.

The mechanics, as Apple’s guide to bringing custom actions and content to Siri lays them out:

• An existing app intent becomes a tool Siri can use when the developer adds the @AppIntent(.tool) Swift macro, which adds conformance to the ToolIntent protocol. An intent that already conforms to a schema in a primary domain does not need the macro.
• Siri relies on a title and a description for each intent, and for each parameter and entity property, to understand what they do.
• To let Siri find custom content, the app makes its entities available to Spotlight; Apple says the system can also retrieve entities from an EnumerableEntityQuery object the app provides.
• An entity can require authentication before Siri presents it, and a property can be given internal visibility so that Siri and other system features do not surface it.
• Custom entities used in cross-app requests need transferable representations.

On when a user must name the app, Apple’s documentation says people do not have to mention an app while it is in the foreground, while one of its Live Activities is active, or when a conversation in the Siri app already mentions it, and that requests need to mention the app while it is in the background (Apple documentation). InfoQ describes the same routing in its own words (InfoQ).

For testing, Apple’s page names the Siri Integration Advisor in Xcode and the Siri Evaluations framework, which “lets you script requests to Siri, measure how Siri handles them, and catch changes in how Siri responds” (Apple documentation).

App skills

Apple’s page on orchestrating complex actions with app skills says each skill is a Markdown file in a Skills.skillsbundle in the Xcode project, in its own folder with a SKILL.md file, and that an app target can contain only one skills bundle. The page says app skills use a subset of the Agent Skills format: the name and description frontmatter fields and a Markdown body, with no other frontmatter fields or supporting files such as scripts or references. The body is free-form instructions limited to 10,000 characters, and Siri reads it only after it decides the skill matches a request.

The same page sets a limit on what a skill does: it says skills cannot enforce deterministic behavior, and that Siri AI does not sequentially perform the tool intents a skill lists. 9to5Mac wrote that app skills “sound very similar to what other LLM-driven AI models offer” (9to5Mac).

What Apple has not settled

Apple said it will follow up with more details about the terms and usage policies for experiences enabled through Siri AI (Apple Developer). The same post says Siri AI is currently unavailable in the EU in iOS, iPadOS and watchOS, a limit InfoQ repeats, and that features relying on server-side models, Siri AI among them, are subject to daily usage limits, with expanded access to be available for a fee in the future.

Two accounts of timing differ in wording, and the Herald does not reconcile them. Apple’s post says the preview provides early access “before first shipping to customers in a few months”, with App Store submission “opening up in the spring”. 9to5Mac wrote that Apple says app skills support “is scheduled to officially roll out in the spring” (9to5Mac).

A separate user control

Separately from the preview, Ars Technica reported on October 26, 2026 that iOS 27.2 added an “Excluded Apps” option to “choose which apps Siri, Search, and suggestions can access”. The Electronic Frontier Foundation, an advocacy organisation rather than a news outlet, wrote on October 28, 2026 that with an app excluded “Siri AI cannot access the contents of the app”, and that doing so can mean losing some features. Neither of those two pages mentions the Developer Preview, and none of the other cited sources discusses the setting, so the cited sources do not say how an excluded app interacts with an app that has adopted the preview.