Join 5,901+ iOS/macOS developers using Codex and agents to build and ship apps. Expect practical tutorials, repeatable workflows, and hard-earned lessons from 7 shipped apps and time at Apple, Microsoft, and GoPro.
How I Build Apps with Codex and GPT-5.4
|
My iOS and macOS app development workflow has changed since my last GPT-5.2 Workflow video. GPT-5.4 lets me iterate on bug fixes, features, and ideas much faster than before. Watch: How I Build Apps with Codex and GPT-5.4 If you want to build apps with agents, use my app-creator skill. It can scaffold a new Xcode project and teach your agent how to create a Makefile for an existing Xcode project. 2 Tactics You Can Steal#1 Use a Learnings.md File with Your AgentSelf-improvement is one of the holy grails for agents. Give them a place to capture lessons so they can avoid repeated mistakes. Ask your agent: Please create a
Learnings.md file. Add any insights from this session that would help you work with tools, or prevent bad tool calls or buggy code. Please append knowledge as you work so we can be proactive. Create Markdown front matter and a table of contents with guidance on how future agents can update it.
Add an
Agents.md onboarding rule to read and update Learnings.md after any problem or bug that requires extra effort to solve.Periodically, ask the agent to review the conversation and append new learnings. Over time, ask it to reorganize the file for future agents. #2 Just Talk to ItGPT-5.4 and Codex 5.3 work well with a full plan, but they also handle small fixes with very little detail. I prefer a hands-on workflow: request a small change, test it, and steer from there. Skip the big plan. Take a screenshot, draw a sketch, or ask for one small task. You don’t need to be comprehensive. Let Codex plan just-in-time. I want to do XYZ. Please use the TODOs to make a plan and implement the feature. When the request is small, you can test the result in minutes and change direction before you fully know what you want. My Workflow:
This loop is much faster than spending 30 to 60 minutes planning and re-planning a feature. Play testing is more fun than creating a master document. Reserve “Plan mode” for initial app concepts or larger features it can build while you sleep. Pro TipEnable the new Fast mode with the latest Codex CLI (and Codex app). Type It runs about 1.5x faster (and uses 2x tokens). 5 Resources and Links
Community Spotlight
Quick QuestionWhat model do you prefer for coding? GPT-5.4 or GPT-5.3-Codex? Talk soon, Paul Solt P.S. Next week, we’ll talk about how to improve your documentation. |
AI Code Brief - Paul Solt
Join 5,901+ iOS/macOS developers using Codex and agents to build and ship apps. Expect practical tutorials, repeatable workflows, and hard-earned lessons from 7 shipped apps and time at Apple, Microsoft, and GoPro.
Hey Reader, Agents write better code when they can read docs instead of guessing from memory. A 2026 paper found up to a 20% improvement in first-try code accuracy when models were given the right programming context. So what do you do with that? Don’t rely on the agent to know everything from their training set. Instead, provide tools or local docs that they can reference. Your local docs should include sample code so agents can use the code correctly (the first time). If you’ve ever read...
Hey Reader, I’m launching early access for my new app-creator agent skill for iOS/macOS apps today! In this email: 2 Tactics You Can Steal This Weekend 5 Resources and Links Community Spotlight What does app development look like in 2026? Coding has forever changed over the last 3 months. I’m all-in on app development with Codex 5.3. It’s a workhorse. If you’re an idea person still learning the basics, you have a huge opportunity. Gone are the days when you need to know every line of code....
Hey Reader, This week is exciting. GPT-5.3-Codex launched today, so I put together a short video covering the five key updates (and a demo of what it can do). I didn't want to go back to GPT-5.2, after I got early access to GPT-5.3-Codex last week. The 5.3 model is faster and smarter. I can do more in less time. Watch here: GPT-5.3-Codex Launches Today — 5 Things You Need to Know The new Codex App + Plan mode + GPT-5.3-Codex helped make this video possible. Try it out and let me know what you...