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.

Production-grade SQLite for web, mobile, and CLI projects. Use this skill when designing schemas, tuning PRAGMAs (WAL, busy_timeout, mmap, optimize), modeling writer concurrency (single-writer pool, BEGIN IMMEDIATE, busy retry), building indexes (covering, partial, expression, STRICT, WITHOUT ROWID), paginating with keyset cursors, implementing job queues via `UPDATE ... RETURNING`, full-text search with FTS5 + sqlite-vec, replicating with Litestream / Turso / Cloudflare D1, picking a driver (better-sqlite3, modernc.org/sqlite, GRDB, Room, SQLDelight, expo-sqlite, SQLCipher), or running the 12-step `ALTER TABLE` rewrite. Pair with go-sql for sqlc + goose against SQLite, apple-dev for GRDB on iOS, and front-dev for in-browser SQLite via OPFS.

Writing, reviewing, refactoring, debugging, or designing Go code — backends, microservices, APIs, CLI tools, daemons, workers, data pipelines, libraries. Umbrella router that delegates to focused sibling Go skills.

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.

Skills that we use to build our software.

Idiomatic Go testing with the stdlib `testing` package and the go-testdeep assertion library. ALWAYS use this skill when writing or reviewing Go tests — table-driven tests with `map[string]testCase`, `t.Run` subtests, `t.Helper()` for assertion helpers, `t.Cleanup`, `t.Parallel`, integration test gating with environment variables, benchmarks (`testing.B`), fuzz tests, go-testdeep operators (`td.Cmp`, `td.CmpError`, `td.CmpNoError`, `td.Struct`, `td.Smuggle`, `td.Between`, `td.Re`, `td.Require`), and the third-party-frameworks debate (go-testdeep when deps are allowed, stdlib-only for dependency-free projects, never testify). Pair with go-sql for testing DB code with sqlc's `Querier` interface, go-http for `httptest` patterns, and go-concurrency for race-detector usage.