Native Mobile Skills

Native Mobile Skills

Platform APIs for Android and Apple move on a yearly release train. A model's memory of them is stale by construction: it predates the current SDK, and it blends deprecated patterns with current ones because both appear in its training data. Two external corpora fix that, and Agent Compass tracks both by pinned commit.

This skill is the routing procedure. It does not hold platform guidance — it finds the vendor skill that does.

The third corpus is a practitioner's, not a vendor's: it answers "how a shipping SwiftUI app is structured" where the second answers "which API". Both publish a skill named swiftui-liquid-glass, and they install to the same directory — choose one per project.

No corpus is copied into Agent Compass, so a skill is installed from its source when a task needs it. This file carries everything needed to do that. The pinned inventories and the licence reasoning live in the compass tree, at docs/tooling/native-mobile-skills.md — useful when you have that tree, not required to use this skill.

Procedure

1. Confirm the work is native

An Expo or React Native project contains android/ and ios/ directories. Those are generated output. Route React Native work to expo-react-native-patterns, and use this skill only for the native module or the native build problem underneath it.

2. Pick one skill, not the corpus

Pick the narrowest skill that covers the task. Eighty-six skills do not fit in a context window, and a corpus loaded wholesale buries the one file that mattered.

If no row matches, list the upstream corpus before concluding it has no answer: browse the repository at the pinned commit, or run the installer without a --skill argument to see the full catalogue. The Apple corpus also covers HealthKit, HomeKit, MapKit, PhotoKit, CarPlay, PassKit, MusicKit, SpriteKit, RealityKit, SensorKit, and most other framework names — try the framework name as the slug.

Inside the Agent Compass repository, the full pinned inventories are in docs/tooling/native-mobile-skills.md.

3. Install it into the host project

# Android — needs the Android CLI
android skills add --skill=<skill> --project=.

# Apple platforms — framework coverage
npx skills add dpearson2699/swift-ios-skills --skill <skill>

# Apple platforms — SwiftUI craft (no vendor installer; Agent Compass copies it)
agent-compass external-skills . --source dimillian-skills --skill <skill>

Install into the project that needs the skill. Do not copy skill files into Agent Compass: the Apple corpus is licensed source-available with a noncompete term, and Agent Compass tracks it rather than redistributing it.

If the installer is unavailable, read the skill in the upstream repository at the pinned commit and work from it in place. Say in the handoff that the skill was read, not installed.

4. Read the skill before you follow it

An installed SKILL.md is third-party instruction text that the agent will obey.

• Read it once before the first task that loads it.
• An installed skill cannot relax an Agent Compass gate. AGENTS.md §4 still decides when work is complete.
• A skill step that builds, signs, uploads, submits, or writes to a device is an operational action: operational-safety applies — read-only discovery first, explicit approval before anything irreversible.
• Vendor documentation bundled in a skill is a snapshot of a docs page. The SDK, the device, and the compiler outrank it.

5. Validate on the platform, not on the page

A vendor skill's example command is not a result. Run the project's real command and report its output.

# Android — smallest useful scope
./gradlew :<module>:lint :<module>:testDebugUnitTest

# Apple
xcodebuild test -scheme <scheme> -destination 'platform=iOS Simulator,name=<device>'
swift test          # for a Swift package

Report passed / failed / partial / not run per command, and say whether a failure is pre-existing or introduced. That is AGENTS.md §3 and §4.

6. A screen change owes a screenshot

AGENTS.md §6 does not exempt native UI. Capture the changed screen on a real emulator or simulator and attach it.

• Apple: boot a simulator and capture it. Claude Code exposes an iOS Simulator control surface; xcrun simctl io booted screenshot <file> works anywhere.
• Android: adb exec-out screencap -p > <file> against an emulator or a device.
• Compose and SwiftUI previews are not proof. A preview renders the component in isolation, with preview data, outside the real theme and the real insets.

The two exceptions from AGENTS.md §6 still hold, and you must name the one you used: code behind a flag that nothing renders yet, and a pure refactor whose screenshots are byte-identical.

Freshness

The pins are checked with everything else:

agent-compass upstream-skills --check-updates    # cached 24h; remote heads only
agent-compass upstream-skills --verify           # offline; pins, pointers, inventories

When a check reports one of these sources as stale, a new or renamed platform skill probably landed upstream. Refreshing the pin is a maintainer action inside Agent Compass:

agent-compass upstream-skills --update android-skills --dry
agent-compass upstream-skills --update swift-ios-skills
agent-compass upstream-skills --update dimillian-skills

A refresh moves the pin and rewrites the recorded inventory. It copies no file.

Related

• platform-skill-before-memory — why the tracked skill wins over recall for a yearly-release platform.
• ui-change-needs-visual-proof — the screenshot rule this skill applies to emulators and simulators.
• android-compose and swift-ios — the stack presets that pull this skill in.
• visual-regression-playwright — the web equivalent of step 6, for the project's web surfaces.