---
id: existential-birds/beagle/watchos-code-review
version: "35c1b33f"
license: Apache-2.0
install: manual
updated: 2026-07-21
---

# watchos-code-review — This skill audits watchOS applications against framework-specific patterns for app lifecycle management, scene handling, and delegate setup. It checks complications using WidgetKit or ClockKit, WatchConnectivity message passing and file transfers, and enforces memory and battery constraints for background execution.

Publisher: existential-birds · Stars: 74 · Updated: 2026-07-21

Install (manual): `git clone https://github.com/existential-birds/beagle`

## SKILL.md

# watchOS Code Review

## Quick Reference

| Issue Type | Reference |
|------------|-----------|
| App lifecycle, scenes, background modes, extended runtime | [references/lifecycle.md](references/lifecycle.md) |
| ClockKit, WidgetKit, timeline providers, Smart Stack | [references/complications.md](references/complications.md) |
| WCSession, message passing, file transfer, reachability | [references/connectivity.md](references/connectivity.md) |
| Memory limits, background refresh, battery optimization | [references/performance.md](references/performance.md) |

## Review Checklist

- [ ] SwiftUI App protocol used with `@WKApplicationDelegateAdaptor` for lifecycle events
- [ ] `scenePhase` read from root view (not sheets/modals where it's always `.active`)
- [ ] `WKExtendedRuntimeSession` started only while app is active (not from background)
- [ ] Workout sessions recovered in `applicationDidFinishLaunching` (not just delegate)
- [ ] Background tasks scheduled at least 5 minutes apart; next scheduled before completing current
- [ ] `URLSessionDownloadTask` (not `DataTask`) used for background network requests
- [ ] WidgetKit used instead of ClockKit for watchOS 9+ complications
- [ ] Timeline includes future entries (not just current state); gaps avoided
- [ ] `TimelineEntryRelevance` implemented for Smart Stack prioritization
- [ ] WCSession delegate set before `activate()`; singleton pattern used
- [ ] `isReachable` checked before `sendMessage`; `transferUserInfo` for critical data
- [ ] Received files moved synchronously before delegate callback returns

## When to Load References

- Reviewing app lifecycle, background modes, or extended sessions -> lifecycle.md
- Reviewing complications, widgets, or timeline providers -> complications.md
- Reviewing WCSession, iPhone-Watch communication -> connectivity.md
- Reviewing memory, battery, or performance issues -> performance.md

## Output Format

Report issues using: `[FILE:LINE] ISSUE_TITLE`

Examples:

- `[WatchApp.swift:18] WKExtendedRuntimeSession started while app not active`
- `[ConnectivityManager.swift:42] WCSession.activate() before delegate assignment`
- `[ComplicationTimeline.swift:67] Timeline has no future entries`

## Hard gates (before reporting)

Complete **in order** for each finding you intend to report. Do not advance until the pass condition is satisfied.

1. **Location artifact** — The finding includes `[FILE:LINE]` (or a line range) copied from the current file contents; the path resolves in this repo.
2. **Scope read** — You read the full surrounding unit: the `View` body, `WKApplicationDelegate` / scene method, `TimelineProvider` implementation, `WCSessionDelegate` callback, or workout/background task handler that owns the behavior—not only a diff hunk.
3. **watchOS or pairing claim** (only if the finding depends on background modes, complication/timeline contracts, `WCSession` reachability or transfer semantics, workout or extended runtime rules, or device-specific limits) — You name one concrete artifact you inspected (for example `Info.plist` / target capabilities for background modes, the `WK*` / `WCSession` call order in source, entitlements, or a subsection you read in the matching doc from [Quick Reference](#quick-reference)) **or** you downgrade the item to an open question in [Review Questions](#review-questions).
4. **Protocol** — Pre-report steps in [review-verification-protocol](../review-verification-protocol/SKILL.md) are satisfied for this item (no finding if they are not).

Use the issue format `[FILE:LINE] ISSUE_TITLE` for each reported finding. Hard gate 4 is the full pre-report checklist for this skill’s review type.

## Review Questions

1. Is the app using modern SwiftUI lifecycle with delegate adaptor?
2. Are background tasks completing properly (calling `setTaskCompletedWithSnapshot`)?
3. Is UI update frequency reduced when `isLuminanceReduced` is true?
4. Are WatchConnectivity delegate callbacks dispatching to main thread?
5. Is `TabView` nested within another `TabView`? (Memory leak on watchOS)


[View on SkillFed](https://skillfed.io/existential-birds/beagle/watchos-code-review) · [View on GitHub](https://github.com/existential-birds/beagle)