Most validation code is one giant function that walks a tree and appends to an error array through a forest of if statements. OpenAPIKit showed me a better way, a validation is a small composable value, the description states the correct state, and every error already knows where it lives
Mihaela Mihaljević Jakić is a Senior iOS and macOS engineer who builds AI powered developer tools for the Apple ecosystem. Her main project is Cupertino, an open source local MCP server that gives AI agents including Claude, Cursor, VS Code, Zed, and others offline access to over 302,000 pages across 307 Apple frameworks. It runs on your machine, answers in under 100 milliseconds, and sends nothing to the cloud. Before AI tooling, Mihaela spent over 15 years shipping iOS, macOS, and cross platform apps for clients across Europe, with a focus on architecture, Swift concurrency, and modular Swift Package layouts. She is currently writing a three book series on production Swift architecture including Extreme Packaging AI Ready Swift Architecture, OpenAPI First Swift Client Server and Everything Between, and UI Patterns in Swift covering SwiftUI, UIKit, and AppKit. Her work now includes Swift server backends with OpenAPI driven type safe APIs, MCP server design and AI agent integration for Apple platform workflows, senior iOS and macOS architecture with Swift 6 strict concurrency, technical writing, podcast appearances, and open source maintenance.
