dat-conventions

Swift patterns, async/await, naming conventions, key types for DAT SDK iOS development

DAT SDK Conventions (iOS)

Architecture

The SDK is organized into four modules:

MWDATCore: Device discovery, registration, permissions, device selectors
MWDATCamera: Stream, VideoFrame, photo capture
MWDATDisplay: Display capability, display UI components, icons, images, buttons, video
MWDATMockDevice: MockDeviceKit for testing without hardware

Swift Patterns

Use async/await for all SDK operations — the SDK is fully async
Use AsyncSequence / publisher .listen {} for observing streams
Annotate UI-updating code with @MainActor
Never block the main thread with frame processing
Handle errors with do/catch — the SDK throws typed errors

Naming Conventions

Type	Convention	Example
Entry point	`Wearables.shared`	`Wearables.shared.startRegistration()`
Device sessions	`*Session`	`DeviceSession`
Capabilities	Named by function	`Stream`
Selectors	`*DeviceSelector`	`AutoDeviceSelector`, `SpecificDeviceSelector`
Config	`*Configuration`	`StreamConfiguration`
Publishers	`*Publisher`	`statePublisher`, `videoFramePublisher`

Imports

import MWDATCore    // Registration, devices, permissions
import MWDATCamera  // Stream, VideoFrame, photo capture
import MWDATDisplay // Display, FlexBox, Text, Button, Image, Icon, VideoPlayer

For testing:

import MWDATMockDevice  // MockDeviceKit, MockGlasses, MockCameraKit

Key Types

Wearables — SDK entry point. Call Wearables.configure() at launch, then use Wearables.shared
Stream — Camera streaming session. Create with config + device selector
Display — Display capability attached to a started DeviceSession
VideoFrame — Individual video frame with .makeUIImage() convenience
AutoDeviceSelector — Automatically selects the best available device
SpecificDeviceSelector — Selects a specific device by identifier
StreamConfiguration — Configure video codec, resolution, frame rate
MockDeviceKit — Factory for creating simulated devices in tests

Error Handling

do {
    try Wearables.configure()
} catch {
    // Handle configuration error
}

do {
    try await Wearables.shared.startRegistration()
} catch {
    // Handle registration error
}

Build and Test

# Install dependencies via Swift Package Manager
# In Xcode: File > Add Package Dependencies > enter repo URL

# Build from command line
xcodebuild -scheme MWDATCore -destination 'platform=iOS Simulator,name=iPhone 16'

# Run tests
xcodebuild test -scheme MWDATCoreTests -destination 'platform=iOS Simulator,name=iPhone 16'

For sample apps:

# Open the sample app workspace
open ExternalSampleApps/CameraAccess/CameraAccess.xcodeproj

# Build and run on simulator (uses MockDeviceKit - no glasses needed)
xcodebuild -scheme CameraAccess -destination 'platform=iOS Simulator,name=iPhone 16'

Development Workflow

Add SDK via Swift Package Manager (SPM) in Xcode
Import modules (MWDATCore, MWDATCamera, MWDATDisplay when rendering Display content)
Configure at app launch: try Wearables.configure()
Build with Xcode or xcodebuild
Test with MockDeviceKit - no physical glasses required
Debug using Xcode console for SDK logs

Live docs search

If your editor supports remote MCP servers, connect https://mcp.developer.meta.com/wearables and use search_dat_docs for current DAT setup, session lifecycle, camera streaming, MockDeviceKit, permissions, and exact API symbols. This public docs server does not require authentication; do not configure tokens, OAuth, or custom authorization headers for it.

Use llms.txt when your tool only supports static reference context.