macOS Golden Gate 27.3 beta 1 shows Markdown in Quick Look with its formatting applied, so a .md file previews as headings, lists and links instead of raw syntax. Apple’s new Siri AI app skills are Markdown files too, which means developers testing the beta write their Siri instructions in the same format.
Apple released the beta to developers on November 3, and the Siri AI developer preview that supports app skills runs in it. Notes already uses the format, with Markdown copy and paste in iOS 27.
Markdown in Quick Look replaces raw syntax with formatted text
Before this beta, Quick Look showed a .md file as plain text with its raw Markdown syntax in view. The first macOS Golden Gate 27.3 beta renders the same file with headings, bold text, lists and links, so you can read it without opening an editor. Markdown is a plain-text format that converts to HTML, and it was designed so a file stays readable even when nothing renders it.
Notes has handled Markdown since iOS 26, when it started importing and exporting .md files. iOS 27 added automatic conversion of pasted Markdown and a Copy as Markdown option.
Siri AI app skills are Markdown files that teach Siri how an app works
A skill is a SKILL.md file with a name, a one-line description and a Markdown body of up to 10,000 characters. Siri AI reads only the description at first to decide whether the skill fits a request, and it opens the body after a match.
Developers add a skills bundle in Xcode, and each skill goes in its own folder named with lowercase letters, numbers and hyphens. An app target can hold only one bundle, and if the bundle is missing from the target or has compile errors, the app gives Siri no skills.
Skills use a subset of the Agent Skills format, so only the name and description fields and the Markdown body work. Scripts and reference files are not supported.
A shopping app, for example, can use a skill to explain how to search items, add them to a cart, pick payment and delivery, review the cart and confirm the purchase. Skills can also tell Siri which action to prefer when several could apply and what to avoid.
These are some of the actual skills Apple is using for Siri AI in iOS 27.3
– there’s a skill to teach Siri how to select and insert text in Notes
– they made a skill to tell Siri about file types supported in the Files app
– a lot of examples of what NOT to do (sign of an old model)— Federico Viticci (@viticci) November 4, 2026
Siri AI reads skills as guidance and does not follow them step by step
Skills do not force a fixed order. Siri AI treats them as extra context and does not run the listed actions one after another, so a skill cannot enforce fixed behavior. They work best when they name actions by what they do, such as calling the get weather tool first, and skip details the app’s code already covers.
Testing happens on a real device, since the Simulator does not work for it, or through TestFlight with internal testers. The Siri AI developer preview needs a device that supports Apple Intelligence, and App Store apps cannot use it until submissions open in the spring.
A known issue affects Siri on the Mac in the macOS Golden Gate 27.3 beta. Siri cannot find app entities that third-party apps donate to Spotlight unless the entities conform to a schema. Apple says Siri AI can surface any entity in the Spotlight semantic index, so the Mac beta currently falls short of that.
