A guide to building apps for watchOS, Apple's operating system for Apple Watch, with SwiftUI, Watch Connectivity, and watch complications. Complications are small pieces of app information shown on a watch face.

Use it to build or review watch apps, sync data between an iPhone and Watch, create complications and widgets, track workouts, and support watch accessibility features.

It explains watch-specific interaction, display, syncing, background, health, widget, and accessibility concerns instead of treating the watch like a small phone.

watchOS — Skill for Claude Code by rshankras/claude-code-apple-skills

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent

npx skills add rshankras/claude-code-apple-skills --skill watchos

Clone the repo

git clone --depth 1 https://github.com/rshankras/claude-code-apple-skills

Made for: Claude Code.

Or install apple-skills, the plugin that ships this one along with the rest of its 182 skills.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/skills/rshankras/claude-code-apple-skills/watchos/github.svg)](https://agentmods.dev/skills/rshankras/claude-code-apple-skills/watchos)

Your own site

<a href="https://agentmods.dev/skills/rshankras/claude-code-apple-skills/watchos"><img src="https://agentmods.dev/badge/skills/rshankras/claude-code-apple-skills/watchos/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/rshankras/claude-code-apple-skills/watchos"><img src="https://agentmods.dev/badge/skills/rshankras/claude-code-apple-skills/watchos.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 39 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 3,551 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits

Socket pass 21 Oct 2026
Snyk pass 21 Oct 2026

How audits are shown

Origin original No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.00039	$0.03551
Opus 5.5	$0.00016	$0.01420
Sonnet 5.5	$0.00008	$0.00710
Haiku 4.5	$0.00004	$0.00355

Measured 2d ago against content hash 347376d31d4b, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

watchOS scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/watchos/SKILL.md · 459 lines

How it starts

The opening of the file, as written. The whole thing — 459 lines — stays where its author put it; the contents beside it link to each section on GitHub.

watchOS Development

Comprehensive guidance for watchOS app development with SwiftUI, Watch Connectivity, and complications.

When This Skill Activates

Use this skill when the user:

Is building a watchOS app or Watch extension
Asks about Watch Connectivity (iPhone ↔ Watch sync)
Needs help with complications or ClockKit
Wants to implement watch-specific UI patterns
Asks about WidgetKit complications or migrating from ClockKit to WidgetKit
Wants to build watch face complications (accessoryCircular, accessoryRectangular, accessoryCorner, accessoryInline)
Asks about HealthKit on watchOS, workout sessions, heart rate, or fitness tracking
Needs Extended Runtime sessions for background workout tracking
Wants to build watchOS widgets or Smart Stack widgets
Asks about widget relevance, Smart Stack ordering, or widget suggestions
Needs to share widgets cross-platform between iOS and watchOS
Asks about watchOS accessibility — VoiceOver, AssistiveTouch, or Dynamic Type on the Watch

Key Principles

1. Watch-First Design

Glanceable content - users look for seconds, not minutes
Quick interactions - 2 seconds or less
Essential information only - no scrolling walls of text
Large touch targets - minimum 38pt height

2. Independent vs Companion

Prefer independent Watch apps when possible
Use Watch Connectivity for data sync, not as dependency
Cache data locally for offline access
Handle connectivity failures gracefully

3. Performance

Minimize background work (battery)
Use complication updates sparingly
Prefer timeline-based content over live updates
Keep views lightweight

watchOS Design Rules (WWDC20/23)

The Ten-Second Test

Design for roughly ten seconds of attention: "if you had ten seconds of someone's attention, which information would you surface?" Launch directly into that detail view — chosen by location, recency, or frequency — and make it so unmistakable it needs no title.

Read the full file on GitHub · 459 lines

Files

What ships with it

4 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

2d ago First seen · 459 lines · 39 tokens per session scan A 347376d31d4b

Subscribe to this mod's changes

watchOS is a skill published in the GitHub repository rshankras/claude-code-apple-skills (864 stars, last pushed 2d ago), licensed MIT. It adds 39 tokens to every session and 3,551 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-11-05.

Kotlin and Swift Languages Mobile agent-skills anthropic app-store apple aso claude

watchOS next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
watchOSrshankras/claude-code-apple-skills	Skill	864	2d ago	MIT	A	39	Claude Code
swift-expertpersonamanagmentlayer/pcl	Skill	44	11d ago	Apache-2.0	A	76	Claude Code
ios-expertpersonamanagmentlayer/pcl	Skill	44	11d ago	Apache-2.0	A	64	Claude Code
ios-swiftui-productJasonColapietro/ios-app-dev-skills	Skill	9	2mo ago	MIT	A	67	Codex
swiftui-maxDev869/swift-tothemax	Skill	7	4mo ago	MIT	A	271	Claude Code
apple-dev-conductorDev869/swift-tothemax	Skill	7	4mo ago	MIT	A	156	Claude Code
kotlin-patternssoftspark/ai-toolkit	Skill	179	10d ago	Apache-2.0	A	51	Claude Code