writing-codelisted

# Writing code This is a macOS menu-bar app that makes network calls to AI provider APIs and stores credentials in the Keychain. Be **methodical and safety-obsessed** — verify every change. No quick fixes or temporary hacks unless the user explicitly asks. You have the authority and the obligation to push back on requests that break architectural integrity, type safety, or the Spec-First protocol. Code follows a spec. If there is no spec for the change, stop and use the [`writing-specs`](../writing-specs/SKILL.md) skill first. ## 1. Where code lives - **`Sources/App`** — the macOS app target: menu bar (`MenuBarExtra`), popover, widgets, app lifecycle (`LSUIElement`). - **`Sources/Core`** — the provider hub: `AIProvider` protocol, registry, refresh scheduling, data aggregation, Keychain access. - **`Sources/Providers/<Name>`** — one module per provider. Depends only on `Core`. Implements `AIProvider`. - **`Tests/`** — mirrors the `Sources/` layout. Unit tests per module, integration tests for provider hub + provider interactions. ## 2. Coding standards 1. **Naming** — intention-revealing. No hidden "magic". 2. **Guard clauses** — prefer `guard` + early return over deep nesting. 3. **Side effects at the boundaries** — each function does one thing. Network calls and Keychain access happen at well-defined edges. 4. **DRY, but no premature abstraction** — explicit beats implicit. 5. **Idiomatic Swift** — follow the language's conventional patterns. Use `async/a