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dpearson2699/swift-ios-skills

Agent skills for iOS, iPadOS, Swift, SwiftUI, and modern Apple framework development.

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SKILL.mdskills/energykit/

name:
energykit
description:
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.

EnergyKit

Provide grid electricity forecasts to help users choose when to use electricity. EnergyKit identifies times when grid electricity is relatively cleaner and, when cost information is available, less expensive. Apps use that guidance to shift or reduce managed device load. 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. Enable the EnergyKit capability in Xcode so the entitlement is added to the app target. Treat this as a top-level setup prerequisite before writing guidance queries, venue lookup, load-event submission, or insight code. Missing permission can surface as EnergyKitError.permissionDenied.

Import

import EnergyKit

Platform availability: Core EnergyKit APIs are iOS 26.0+ and iPadOS 26.0+. Some insight breakdown APIs, including grid cleanliness categories, are iOS 26.1+ / iPadOS 26.1+ and need availability guards.

Core Concepts

EnergyKit provides two main capabilities:

  1. Electricity Guidance -- time-weighted forecasts telling apps when electricity is cleaner and, when rate data is available, less expensive
  2. Load Events -- telemetry from managed devices (EV chargers, HVAC) submitted by the same device/app that requested guidance so EnergyKit can generate insights

Key Types

TypeRole
ElectricityGuidanceForecast data with weighted time intervals
ElectricityGuidance.ServiceInterface for obtaining guidance data
ElectricityGuidance.QueryQuery specifying shift or reduce action
ElectricityGuidance.ValueA time interval with a rating (0.0-1.0)
EnergyVenueA physical location (home) registered for energy management
ElectricVehicleLoadEventLoad event for EV charger telemetry
ElectricHVACLoadEventLoad event for HVAC system telemetry
ElectricityInsightServiceService for querying energy/runtime insights
ElectricityInsightRecordHistorical energy or runtime data, optionally broken down by tariff or 26.1+ grid cleanliness
ElectricityInsightQueryQuery for historical insight data

Suggested Actions

ActionUse Case
.shiftDevices that can move consumption to a different time (EV charging)
.reduceDevices that can lower consumption without stopping (HVAC setback)

Querying Electricity Guidance

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

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.

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

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)
            .padding(.vertical)
            .background(color.opacity(0.2))
            .foregroundStyle(color)
            .clipShape(Capsule())
    }
}

Energy Venues

An EnergyVenue represents a physical location registered for energy management.

// 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

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 generate electricity insights. The same EnergyKit-capable device/app that requested electricity guidance must submit the corresponding load events, using the guidance token returned by EnergyKit. Do not invent a token.

EV Charger Load Events

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

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

StateWhen to Use
.beginDevice starts consuming electricity
.activeDevice is actively consuming (periodic updates)
.endDevice stops consuming electricity

For EV charging, record begin/end, one steady sample about every 15 minutes, and extra samples for user actions, pauses, new guidance, or rapid power changes. For HVAC, submit separate events when equipment starts, when heating or cooling stage changes (heat stage 1 -> 2, heat -> cool, cool -> idle), and when equipment stops. Batch events when practical for performance. Insights are only available for submitted events, and load events for an EnergyVenue are visible to people who share the associated Home in the Home app.

Electricity Insights

Query historical energy and runtime data for devices using ElectricityInsightService. An empty ElectricityInsightQuery.Options option set returns totals only; it does not populate cleanliness or tariff breakdowns. Request .cleanliness and/or .tariff only when the UI needs those breakdowns. Do not substitute MetricKit app power metrics for EnergyKit insights; EnergyKit insights depend on EnergyKit load events submitted for the managed device.

Choose insight granularity from the requested range. For a seven-day view, query .hourly; use .daily only when the query covers at least a calendar month.

func queryEnergyInsights(deviceID: String, venueID: UUID) async throws {
    let sevenDaysAgo = Calendar.current.date(
        byAdding: .day,
        value: -7,
        to: Date()
    )!

    let query = ElectricityInsightQuery(
        options: [.cleanliness, .tariff],
        range: DateInterval(
            start: sevenDaysAgo,
            end: Date()
        ),
        granularity: .hourly,
        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 #available(iOS 26.1, iPadOS 26.1, *),
           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. Choose a range that matches Apple's minimum aggregation windows: hourly for at least a calendar week, daily for at least a calendar month, weekly for at least six months, and monthly or yearly for at least a calendar year. See references/energykit-patterns.md for full insight examples.

Common Mistakes

DON'T: Forget the EnergyKit entitlement

Without the entitlement, EnergyKit APIs can fail with permission errors such as EnergyKitError.permissionDenied. Treat the EnergyKit capability as setup, not as an implementation detail to discover after writing queries.

DON'T: Ignore unsupported regions

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

// 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 was in effect. Store the token returned from EnergyKit on the device that fetched it and pass that real token to load event submissions.

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

// 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.

// 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.

// 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
  • No placeholder or fabricated guidance tokens are used in load events
  • The same EnergyKit-capable device/app that requested guidance submits the corresponding load events
  • Venues discovered via EnergyVenue.venues() before querying guidance
  • Load event sessions follow .begin -> .active -> .end lifecycle
  • EV/HVAC event cadence follows Apple guidance and events are batched when practical
  • ElectricityGuidance.Value.rating interpreted correctly (lower is better)
  • SuggestedAction matches the device type (.shift for EV, .reduce for HVAC)
  • Insight queries use appropriate minimum ranges for their granularity
  • Empty insight query options are treated as totals-only, not as cleanliness or tariff requests
  • MetricKit power telemetry is not used as a substitute for EnergyKit load events or insights
  • Grid cleanliness insight fields are guarded for iOS/iPadOS 26.1+
  • Users understand load events are shared with people who share the Home
  • Rate limiting handled via EnergyKitError.rateLimitExceeded
  • Service unavailability handled with retry logic

References

skills

energykit

SKILL.md

README.md

tile.json