apple-hig skill
157 condensed Apple HIG references for an agent and a /duo command that adapts an existing iOS app to the folding iPhone
- 830 ★ on the repository
- Last commit
- MIT
Minimal access
Why this level
- The skill holds reference texts and instructions. Enforce mode starts subagents and a scoring script, and `/duo` edits app code only after approval.
Install
- Works in
In your terminal, with SkillFoxx CLI
npx skillfoxx add skills/apple-higDetects the agents on your machine, shows the access level and pins the version.
Other ways to install
Access and checks
How we reviewMinimal accessThe tool runs nothing and makes no network calls.
- The skill holds reference texts and instructions. Enforce mode starts subagents and a scoring script, and `/duo` edits app code only after approval.
This is third-party code. Review the repository files before installing.
What it does
The `apple-hig` skill gives the agent a reference of the Human Interface Guidelines: iOS, iPadOS, macOS, tvOS, visionOS and watchOS. The author cut Apple's source text from 261,621 to 90,027 words while keeping exact values, conditions and recommendation strength. The agent first reads the routing index `routing-index.md` and loads only the needed files from `references/hig/`. The `/duo` command walks an existing iOS app through screen assessment, matching Apple's guidance for the folding iPhone Duo, approval of changes and implementation in SwiftUI or UIKit inside the app's own code. A separate enforce mode is started by name: two independent reviewers score the interface against the HIG, the agent repairs findings and re-reviews for up to three cycles. A pass needs 90 out of 100 and confirmed evidence.
Who it is for. iOS developers and interface designers who need an agent to answer from the HIG with exact values and to prepare an app for iPhone Duo.
Good fit when
- The agent checks a SwiftUI screen against Apple's recommendations on spacing, sizes and element behaviour.
- A shipped iOS app has to be adapted to the folding iPhone: assess screens, agree on changes and put them in code.
- An independent review of an interface by two reviewers is needed, with a score and a re-check after fixes.
- A question concerns a specific component such as action sheets, charts or CarPlay and exact numbers are needed.
Not a fit when
- Apple's official text verbatim is needed: the references are condensed.
- The interface does not target Apple platforms.
- On-device certification is required: source review does not replace it.
Example request
/duo Assess our iOS app's screens for iPhone Duo, propose changes by Apple's rules and, after my approval, make them in SwiftUI.Limitations
The references reflect a snapshot of Apple's pages from 12 September 2026 and a skill release of 27 September 2026. The cut is 65.6 percent rather than the 75 targeted because accuracy took priority. Source review does not prove behaviour in an app and does not replace device tests. Automatic discovery of the skill is not tested in every host, so `/duo` is sometimes copied by hand. Enforce mode needs subagents, Python 3.10 or newer and a way to observe the finished interface. The project is independent and not endorsed by Apple, and rights to Apple's texts stay with Apple.
How to disable. Delete the `apple-hig` folder from the agent's skills directory and the `duo.md` file if you copied it into the custom commands directory.
FAQ
How do I install apple-hig in Claude Code?
Copy the complete `apple-hig/` folder into the agent's skills directory or give the agent the ready request text from the README with the repository address. Then check that `/duo` is available.
What does the /duo command do?
It takes an app through steps: screen assessment, matching Apple's iPhone Duo rules, recommendations for approval and implementation in SwiftUI or UIKit. It draws no web mockups.
Is Python required?
Not for ordinary answers. Python 3.10 or newer is needed for the optional routing helper and required for enforce scoring.
What should be updated when moving from the June version?
Replace the skill folder entirely rather than merging files: the references moved from `distilled/` to `references/hig/`.
How do I start enforce mode?
Ask by name: "Use apple-hig in enforce mode to review and fix this interface". Two reviewers score the interface and the agent fixes findings for up to three cycles.
Discussion
No questions or reviews yet.
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README in short
The README covers the 27 September 2026 release, manual and prompt-based installation, the Duo and enforce modes and the repository layout. Reference size measurements and license terms are given separately.
README badge
Original SKILL.md
--- name: apple-hig description: > Apple Human Interface Guidelines reference, updated for iPhone Duo and OS 27. Provides authoritative platform-specific design rules, component specifications, exact measurements, and interaction patterns for iOS, iPadOS, macOS, tvOS, visionOS, and watchOS. Use when designing, reviewing, auditing, or fixing any Apple platform UI, or when asked about specific HIG components, sizing, system behaviors, frameworks (HealthKit, SiriKit, ARKit, etc.), or platform conventions. Also use when the user is designing any digital interface and could benefit from established design principles, even without an explicit Apple platform context. Includes a guided /duo workflow that adapts an existing iOS app to iPhone Duo, plus opt-in enforce mode with independent review. --- # Apple HIG Skill Use the distilled HIG references in `references/hig/` through `routing-index.md`. The source snapshot and verified release measurements are in README.md. ## Loading Protocol Release **2026-09-27**; Apple source snapshot **2026-09-12**. For help, installation, version or capability questions, read only this entry point and the relevant README section. Do not load the HIG corpus for setup help. Installing or upgrading this skill includes its `/duo` slash command. After the skill folder is in place, check whether the host already offers `/duo`. If it does not, copy `commands/duo.md` into the host's custom slash-command or custom prompt directory (user-level unless the user asks for one project), confirm `/duo` is available, and tell the user if a restart is needed. Work directly in the conversation and the user's project; do not create a browser intake form, onboarding site, dashboard, or browser setup step. Ordinary guidance is the default. Only an explicit request to apply enforce mode activates its procedure. Read `references/enforce.md` first in that case and check reviewer, Python and observation capabilities before loading the design guidance. A leading `/duo`, `Use apple-hig in Duo mode`, or an explicit request to adapt an existing app for iPhone Duo starts Duo mode: read `references/duo.md` and follow its stages. Questions about the command and ordinary Duo design questions stay ordinary guidance. Duo mode works only in the app's native code; it never produces HTML, SVG, or web mockups. Use the available Python 3.10+ interpreter (`python3` or `python`); do not assume the executable name. Ordinary guidance also works without Python. When Python is available, use the standard-library routing helper to resolve