Implement HTTP handlers that parse requests, invoke use cases, and format responses following REST conventions.
Centralize all configuration constants — environment variables, cache keys — in the constants/ directory with strict naming and export conventions
Handle errors across the three tiers — HTTP/Drizzle layer rejection, service factory validation failure, and component-level try/catch with toast notifications
Implement the functional factory method pattern used across all service layers — the single most important architectural convention in this project
Build forms using TanStack Form with Zod — `formOptions`, `useForm` with `validators`, render-prop `form.Field`, and try/catch submission with toast errors
Apply functional dependency injection where dependencies are passed as function parameters instead of constructor injection — enables trivial testability and loose coupling
Use @repo/api-client SDK hooks (preferred) or raw fetch directly in domain-specific HTTP implementations (extension app only) — no generic HTTP wrapper layer needed
Use when writing, refactoring, or reviewing React components inside a TanStack Start application. Focuses on SOLID component design, composition, and correct use of loaders, server functions, and React Query for client-side state.