Give your simulator superpowers

RocketSim: An Essential Developer Tool
as recommended by Apple

Issue 305
Jan 06, 2026

This week's SwiftLee Weekly covers:

  • Codex Skills for iOS Development
  • Replay network requests inside Swift Tests
  • LLM improvements 12 months later

Enjoy this week's SwiftLee Weekly and Happy New Year!

THIS WEEK'S BLOG POST

Icon Composer: Transforming an AI-generated icon

What do you do when you have a custom ChatGPT project for a new app idea and you need an app icon?

You ask it to generate the app icon for you!

I did so too, and I was happy with the result at first. That was until I found out how Michael Flarup (From The App Icon Book) turned it into a much better looking app icon.

video preview

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CURATED FROM THE COMMUNITY

Dimillian/Skills: My Codex Skills

OpenAI recently launched Agent Skills for Codex build on the open agent skills standard. I was happy to see Thomas Ricouard jumping straight on this, offering skills for common iOS development related tasks.
github.com

Intercepting SwiftUI Sheet Dismissal

What if you want to ask for confirmation before a sheet closes? This technique described by Artem Mirzabekian works great as a solution.
livsycode.com

Replay

There are several solutions for mocking network requests in Swift tests, but this one by Mattt is a new approach I haven’t seen before!
nshipster.com

Have LLMs improved for Swift coding in the last 12 months?

12 months these days is a lot when it comes down to AI-generated code improvements. Matt decided to compare year over year, and the results are impressive.
cocoawithlove.com

Versioned Package.swift Files

Did you know you can create versioned Package.swift files? I’ve seen them before, but I never really understood them. Matt is here to share an important notice.
massicotte.org

SWIFT EVOLUTION

An overview of last week's Swift Proposal state changes. Check them out when they're in review, as it's your opportunity to influence the direction of Swift's future.

There have not been any state changes in the past 7 days.

WHAT I'M WORKING ON

Another app idea

It almost feels embarrassing to admit, but I've started another app project. If you asked me a year ago what I'd recommend doing for success, one of the things would be to focus on a single thing.

More than ever, I feel like I'm reinventing myself. I still believe in focus, and I'm still consciously deciding where to spend my time. However, I also find myself developing differently.

I'm embracing AI and I'm doing a lot of development with agents these days. I'm in the process of optimizing my workflow, optimizing it for higher code quality delivery (and yes, I'll share you all about it once I feel like I have a solid one). This also means that I find myself waiting for AI results more and more often. It's not exceptional for Cursor to run minutes before it completes on a large refactor or feature development.

If you know me, you know I want to make the most of my time. Instead of scrolling through socials while waiting for Cursor to complete, I figured it would make more sense to trigger another AI run for another project. At first, and still, I would do this for RocketSim. Yet, spending time on both RocketSim and my 10K MRR idea was not enough to keep me busy.

What's interesting is that historically, I would write down app ideas for later revisitting. I simply didn't have the time to work on them, and I wanted to guard my focus for RocketSim & SwiftLee. Nowadays, however, it's so easy to get a proof of concept done by AI. For that reason, I'm also optimizing my project setup for reusability, so I can really quickly get going with a new project. This means:

  • Copying codex skills
  • Copying Cursor rules
  • Copying AGENTS.md files
  • Copying linter rules

Basically all the things that help me get a solid AI output.

This new reality means I no longer have to schedule an app idea for later revisit: I can simply build it, try it, and evaluate how it feels.

So yes, I've started another app idea. It's early days, and I don't want to share much about it yet. I'm planning on dropping it in one of the future YouTube episodes when it turns out to become an app idea I truly want to release. I mean, nobody said I would build only one app idea towards 10K MRR, right?

UNTIL NEXT TIME

Continue your Swift development journey

I hope you've enjoyed this week's content. You don't have to wait till next Tuesday for more insights, I share every day on these channels:

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Thank you so much for your support, and until next Tuesday,

Antoine