sys-arch

Skill

Skill

Skill

Skill

Comprehensive macOS and iOS development expertise covering Swift best practices, SwiftUI design patterns, Human Interface Guidelines, Apple frameworks, and performance optimization. Use when developing native Apple applications, implementing SwiftUI interfaces, working with Apple frameworks (Foundation, UIKit, AppKit, Core Data, CloudKit, etc.), optimizing app performance, following HIG principles, or writing production-quality Swift code for iOS, macOS, watchOS, or tvOS platforms.

Professional copywriter for SaaS and startups. Expert in landing page copy, positioning, messaging, conversion optimization, and voice-of-customer research. Use when writing compelling copy for SaaS products, landing pages, marketing materials, or when you need help with product positioning and messaging strategy.

Disciplined Go concurrency. ALWAYS use this skill when writing or reviewing Go code that touches goroutines, channels, `context.Context`, `sync.WaitGroup`, `sync.Mutex` / `sync.RWMutex`, `sync.Once`, `errgroup.Group`, worker pools, fan-out/fan-in pipelines, request cancellation, timeouts, deadlines, or any "run this in the background" pattern. Also use when debugging deadlocks, goroutine leaks, race conditions, or channel-related bugs. Pair with go-errors for error propagation across goroutines.

Building command-line tools in Go with the stdlib `flag` package. ALWAYS use this skill when writing or reviewing Go CLI code — top-level flags with `flag.Parse`, subcommands with `flag.NewFlagSet`, exit codes, writing errors to `os.Stderr`, signal handling, environment-variable fallbacks, `-h`/`-help` output, and `cmd/<tool>` project layout. Avoid reaching for cobra/urfave-cli unless the tool clearly needs it (~5+ subcommands with rich help). Pair with go-style for naming and config patterns, go-errors for exit-code mapping, and go-logging for diagnostic output.

Frontend web development with Bun, Astro, React, Preact, Tailwind CSS v4, and Shadcn UI. ALWAYS use this skill when the user's task involves frontend or web UI work — building websites, web apps, landing pages, dashboards, components, or pages. This includes: Astro islands architecture, React or Preact components, Tailwind styling, Shadcn UI setup, frontend testing with Playwright and Lightpanda, accessibility, web performance, forms, data tables, static sites, SSR, View Transitions, content collections, MDX, deployment to Vercel/Netlify/Cloudflare, or any task mentioning .astro/.tsx/.jsx files, CSS utilities, or frontend build tooling. Even if the user just says "build me a page" or "create a website" — use this skill.

Skills that we use to build our software.