Agent skill

energykit

Query grid electricity forecasts and submit load events using EnergyKit to help users optimize home electricity usage. Use when building smart home apps, EV charger controls, HVAC scheduling, or energy management dashboards that guide users to use power during cleaner or cheaper grid periods.

View SKILL.md on GitHub Repository
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npx add-skill https://github.com/dpearson2699/swift-ios-skills/tree/main/skills/energykit

SKILL.md

EnergyKit

Provide grid electricity forecasts to help users choose when to use electricity. EnergyKit identifies times when there is relatively cleaner or less expensive electricity on the grid, enabling apps to shift or reduce load accordingly. Targets Swift 6.3 / iOS 26+.

Beta-sensitive. EnergyKit is new in iOS 26 and may change before GM. Re-check current Apple documentation before relying on specific API details.

Contents

  • Setup
  • Core Concepts
  • Querying Electricity Guidance
  • Working with Guidance Values
  • Energy Venues
  • Submitting Load Events
  • Electricity Insights
  • Common Mistakes
  • Review Checklist
  • References

Setup

Entitlement

EnergyKit requires the com.apple.developer.energykit entitlement. Add it to your app's entitlements file.

Import

swift
import EnergyKit

Platform availability: iOS 26+, iPadOS 26+.

Core Concepts

EnergyKit provides two main capabilities:

  1. Electricity Guidance -- time-weighted forecasts telling apps when electricity is cleaner or cheaper, so devices can shift or reduce consumption
  2. Load Events -- telemetry from devices (EV chargers, HVAC) submitted back to the system to track how well the app follows guidance

Key Types

Type Role
ElectricityGuidance Forecast data with weighted time intervals
ElectricityGuidance.Service Interface for obtaining guidance data
ElectricityGuidance.Query Query specifying shift or reduce action
ElectricityGuidance.Value A time interval with a rating (0.0-1.0)
EnergyVenue A physical location (home) registered for energy management
ElectricVehicleLoadEvent Load event for EV charger telemetry
ElectricHVACLoadEvent Load event for HVAC system telemetry
ElectricityInsightService Service for querying energy/runtime insights
ElectricityInsightRecord Historical energy data broken down by cleanliness/tariff
ElectricityInsightQuery Query for historical insight data

Suggested Actions

Action Use Case
.shift Devices that can move consumption to a different time (EV charging)
.reduce Devices that can lower consumption without stopping (HVAC setback)

Querying Electricity Guidance

Use ElectricityGuidance.Service to get a forecast stream for a venue.

swift
import EnergyKit

func observeGuidance(venueID: UUID) async throws {
    let query = ElectricityGuidance.Query(suggestedAction: .shift)
    let service = ElectricityGuidance.sharedService

    let guidanceStream = service.guidance(using: query, at: venueID)

    for try await guidance in guidanceStream {
        print("Guidance token: \(guidance.guidanceToken)")
        print("Interval: \(guidance.interval)")
        print("Venue: \(guidance.energyVenueID)")

        // Check if rate plan information is available
        if guidance.options.contains(.guidanceIncorporatesRatePlan) {
            print("Rate plan data incorporated")
        }
        if guidance.options.contains(.locationHasRatePlan) {
            print("Location has a rate plan")
        }

        processGuidanceValues(guidance.values)
    }
}

Working with Guidance Values

Each ElectricityGuidance.Value contains a time interval and a rating from 0.0 to 1.0. Lower ratings indicate better times to use electricity.

swift
func processGuidanceValues(_ values: [ElectricityGuidance.Value]) {
    for value in values {
        let interval = value.interval
        let rating = value.rating  // 0.0 (best) to 1.0 (worst)

        print("From \(interval.start) to \(interval.end): rating \(rating)")
    }
}

// Find the best time to charge
func bestChargingWindow(
    in values: [ElectricityGuidance.Value]
) -> ElectricityGuidance.Value? {
    values.min(by: { $0.rating < $1.rating })
}

// Find all "good" windows below a threshold
func goodWindows(
    in values: [ElectricityGuidance.Value],
    threshold: Double = 0.3
) -> [ElectricityGuidance.Value] {
    values.filter { $0.rating <= threshold }
}

Displaying Guidance in SwiftUI

swift
import SwiftUI
import EnergyKit

struct GuidanceTimelineView: View {
    let values: [ElectricityGuidance.Value]

    var body: some View {
        List(values, id: \.interval.start) { value in
            HStack {
                VStack(alignment: .leading) {
                    Text(value.interval.start, style: .time)
                    Text(value.interval.end, style: .time)
                        .foregroundStyle(.secondary)
                }
                Spacer()
                RatingIndicator(rating: value.rating)
            }
        }
    }
}

struct RatingIndicator: View {
    let rating: Double

    var color: Color {
        if rating <= 0.3 { return .green }
        if rating <= 0.6 { return .yellow }
        return .red
    }

    var label: String {
        if rating <= 0.3 { return "Good" }
        if rating <= 0.6 { return "Fair" }
        return "Avoid"
    }

    var body: some View {
        Text(label)
            .padding(.horizontal, 8)
            .padding(.vertical, 4)
            .background(color.opacity(0.2))
            .foregroundStyle(color)
            .clipShape(Capsule())
    }
}

Energy Venues

An EnergyVenue represents a physical location registered for energy management.

swift
// List all venues
func listVenues() async throws -> [EnergyVenue] {
    try await EnergyVenue.venues()
}

// Get a specific venue by ID
func getVenue(id: UUID) async throws -> EnergyVenue {
    try await EnergyVenue.venue(for: id)
}

// Get a venue matching a HomeKit home
func getVenueForHome(homeID: UUID) async throws -> EnergyVenue {
    try await EnergyVenue.venue(matchingHomeUniqueIdentifier: homeID)
}

Venue Properties

swift
let venue = try await EnergyVenue.venue(for: venueID)
print("Venue ID: \(venue.id)")
print("Venue name: \(venue.name)")

Submitting Load Events

Report device consumption data back to the system. This helps the system improve future guidance accuracy.

EV Charger Load Events

swift
func submitEVChargingEvent(
    at venue: EnergyVenue,
    guidanceToken: UUID,
    deviceID: String
) async throws {
    let session = ElectricVehicleLoadEvent.Session(
        id: UUID(),
        state: .begin,
        guidanceState: ElectricVehicleLoadEvent.Session.GuidanceState(
            wasFollowingGuidance: true,
            guidanceToken: guidanceToken
        )
    )

    let measurement = ElectricVehicleLoadEvent.ElectricalMeasurement(
        stateOfCharge: 45,
        direction: .imported,
        power: Measurement(value: 7.2, unit: .kilowatts),
        energy: Measurement(value: 0, unit: .kilowattHours)
    )

    let event = ElectricVehicleLoadEvent(
        timestamp: Date(),
        measurement: measurement,
        session: session,
        deviceID: deviceID
    )

    try await venue.submitEvents([event])
}

HVAC Load Events

swift
func submitHVACEvent(
    at venue: EnergyVenue,
    guidanceToken: UUID,
    stage: Int,
    deviceID: String
) async throws {
    let session = ElectricHVACLoadEvent.Session(
        id: UUID(),
        state: .active,
        guidanceState: ElectricHVACLoadEvent.Session.GuidanceState(
            wasFollowingGuidance: true,
            guidanceToken: guidanceToken
        )
    )

    let measurement = ElectricHVACLoadEvent.ElectricalMeasurement(stage: stage)

    let event = ElectricHVACLoadEvent(
        timestamp: Date(),
        measurement: measurement,
        session: session,
        deviceID: deviceID
    )

    try await venue.submitEvents([event])
}

Session States

State When to Use
.begin Device starts consuming electricity
.active Device is actively consuming (periodic updates)
.end Device stops consuming electricity

Electricity Insights

Query historical energy and runtime data for devices using ElectricityInsightService.

swift
func queryEnergyInsights(deviceID: String, venueID: UUID) async throws {
    let query = ElectricityInsightQuery(
        options: [.cleanliness, .tariff],
        range: DateInterval(
            start: Calendar.current.date(byAdding: .day, value: -7, to: Date())!,
            end: Date()
        ),
        granularity: .daily,
        flowDirection: .imported
    )

    let service = ElectricityInsightService.shared
    let stream = try await service.energyInsights(
        forDeviceID: deviceID, using: query, atVenue: venueID
    )

    for await record in stream {
        if let total = record.totalEnergy { print("Total: \(total)") }
        if let cleaner = record.dataByGridCleanliness?.cleaner {
            print("Cleaner: \(cleaner)")
        }
    }
}

Use runtimeInsights(forDeviceID:using:atVenue:) for runtime data instead of energy. Granularity options: .hourly, .daily, .weekly, .monthly, .yearly. See references/energykit-patterns.md for full insight examples.

Common Mistakes

DON'T: Forget the EnergyKit entitlement

Without the entitlement, all EnergyKit calls fail silently or throw errors.

swift
// WRONG: No entitlement configured
let service = ElectricityGuidance.sharedService  // Will fail

// CORRECT: Add com.apple.developer.energykit to entitlements
// Then use the service
let service = ElectricityGuidance.sharedService

DON'T: Ignore unsupported regions

EnergyKit is not available in all regions. Handle the .unsupportedRegion and .guidanceUnavailable errors.

swift
// WRONG: Assume guidance is always available
for try await guidance in service.guidance(using: query, at: venueID) {
    updateUI(guidance)
}

// CORRECT: Handle region-specific errors
do {
    for try await guidance in service.guidance(using: query, at: venueID) {
        updateUI(guidance)
    }
} catch let error as EnergyKitError {
    switch error {
    case .unsupportedRegion:
        showUnsupportedRegionMessage()
    case .guidanceUnavailable:
        showGuidanceUnavailableMessage()
    case .venueUnavailable:
        showNoVenueMessage()
    case .permissionDenied:
        showPermissionDeniedMessage()
    case .serviceUnavailable:
        retryLater()
    case .rateLimitExceeded:
        backOff()
    default:
        break
    }
}

DON'T: Discard the guidance token

The guidanceToken links load events to the guidance that influenced them. Always store and pass it through to load event submissions.

swift
// WRONG: Ignore the guidance token
for try await guidance in guidanceStream {
    startCharging()
}

// CORRECT: Store the token for load events
for try await guidance in guidanceStream {
    let token = guidance.guidanceToken
    startCharging(followingGuidanceToken: token)
}

DON'T: Submit load events without a session lifecycle

Always submit .begin, then .active updates, then .end events.

swift
// WRONG: Only submit one event
let event = ElectricVehicleLoadEvent(/* state: .active */)
try await venue.submitEvents([event])

// CORRECT: Full session lifecycle
try await venue.submitEvents([beginEvent])
// ... periodic active events ...
try await venue.submitEvents([activeEvent])
// ... when done ...
try await venue.submitEvents([endEvent])

DON'T: Query guidance without a venue

EnergyKit requires a venue ID. List venues first and select the appropriate one.

swift
// WRONG: Use a hardcoded UUID
let fakeID = UUID()
service.guidance(using: query, at: fakeID)  // Will fail

// CORRECT: Discover venues first
let venues = try await EnergyVenue.venues()
guard let venue = venues.first else {
    showNoVenueSetup()
    return
}
let guidanceStream = service.guidance(using: query, at: venue.id)

Review Checklist

  • com.apple.developer.energykit entitlement added to the project
  • EnergyKitError.unsupportedRegion handled with user-facing message
  • EnergyKitError.permissionDenied handled gracefully
  • Guidance token stored and passed to load event submissions
  • Venues discovered via EnergyVenue.venues() before querying guidance
  • Load event sessions follow .begin -> .active -> .end lifecycle
  • ElectricityGuidance.Value.rating interpreted correctly (lower is better)
  • SuggestedAction matches the device type (.shift for EV, .reduce for HVAC)
  • Insight queries use appropriate granularity for the time range
  • Rate limiting handled via EnergyKitError.rateLimitExceeded
  • Service unavailability handled with retry logic

References

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