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How I built an Apple Watch workout app using Cursor and Xcode (with zero mobile-app experience)

How I built an Apple Watch workout app using Cursor and Xcode (with zero mobile-app experience)

How I AI · Sep 15, 2025

A PM built an AI-powered mobile fitness tracker. Discover his structured workflow using Cursor, Xcode, and even index cards for prototyping.

Treat AI-Generated Code Debt as a Planned "Vibe Refactoring" Phase

Instead of fighting for perfect code upfront, accept that AI assistants can generate verbose code. Build a dedicated "refactoring" phase into your process, using AI with specific rules to clean up and restructure the initial output. This allows you to actively manage technical debt created by AI-powered speed.

How I built an Apple Watch workout app using Cursor and Xcode (with zero mobile-app experience) thumbnail

How I built an Apple Watch workout app using Cursor and Xcode (with zero mobile-app experience)

How I AI·5 months ago

A Second AI Model Can Sanity-Check a PRD Before Coding Begins

To prevent AI coding assistants from hallucinating, developer Terry Lynn uses a two-step process. First, an AI generates a Product Requirements Document (PRD). Then, a separate AI "reviewer" rates the PRD's clarity out of 10, identifying gaps before any code is written, ensuring a higher rate of successful execution.

How I built an Apple Watch workout app using Cursor and Xcode (with zero mobile-app experience) thumbnail

How I built an Apple Watch workout app using Cursor and Xcode (with zero mobile-app experience)

How I AI·5 months ago

Use an AI Assistant to Quiz You on Your Own Generated Codebase

To ensure comprehension of AI-generated code, developer Terry Lynn created a "rubber duck" rule in his AI tool. This prompts the AI to explain code sections and even create pop quizzes about specific functions. This turns the development process into an active learning tool, ensuring he deeply understands the code he's shipping.

How I built an Apple Watch workout app using Cursor and Xcode (with zero mobile-app experience) thumbnail

How I built an Apple Watch workout app using Cursor and Xcode (with zero mobile-app experience)

How I AI·5 months ago

Validate an AI App Idea with Voice Memos, a Python Script, and a Spreadsheet

To validate his fitness tracker idea, developer Terry Lynn first used the Apple Watch's voice memo app to record workouts. He then wrote a simple Python script to process the audio files with GPT-4 and output the structured data into a spreadsheet. This ultra-lean MVP tested the core concept without the overhead of app development.

How I built an Apple Watch workout app using Cursor and Xcode (with zero mobile-app experience) thumbnail

How I built an Apple Watch workout app using Cursor and Xcode (with zero mobile-app experience)

How I AI·5 months ago

Structure Your Codebase for AI Assistants by Keeping Files Under 400 Lines

Human developers may prefer longer files, but AI coding assistants process code in smaller chunks. App developer Terry Lynn intentionally keeps his files small (under 400 lines) to reduce the AI's context window usage, prevent it from getting lost, and improve the speed and accuracy of its code generation.

How I built an Apple Watch workout app using Cursor and Xcode (with zero mobile-app experience) thumbnail

How I built an Apple Watch workout app using Cursor and Xcode (with zero mobile-app experience)

How I AI·5 months ago

Manage AI Coding Risks with Frequent, Automated Git Commits After Each Task

When an AI coding assistant goes off track, it can be hard to undo the damage. Developer Terry Lynn mitigates this risk by programming his AI workflow to make a Git commit before and after each small phase of a task. This creates a trail of "breadcrumbs," allowing him to easily revert to a stable state if the AI makes a mistake.

How I built an Apple Watch workout app using Cursor and Xcode (with zero mobile-app experience) thumbnail

How I built an Apple Watch workout app using Cursor and Xcode (with zero mobile-app experience)

How I AI·5 months ago

Prototype Mobile Apps on Index Cards and Use GPT-4 to Upscale Sketches into Figma

To rapidly iterate on mobile UI, Lynn sketches screens on physical index cards, which have a similar aspect ratio to a phone. He then photographs these low-fidelity mockups and uses GPT-4's image generation to "upscale" them into high-fidelity designs, bridging the gap between physical brainstorming and digital prototyping tools like Figma.

How I built an Apple Watch workout app using Cursor and Xcode (with zero mobile-app experience) thumbnail

How I built an Apple Watch workout app using Cursor and Xcode (with zero mobile-app experience)

How I AI·5 months ago