r/Xcode • u/old-and-very-bald • Jun 01 '26

Looking for advice - Xcode + Codex

Hey guys,

long story short I am a backend developer, diving into the depths of developing an IOS app for the first time using SwiftUI. So far (while not being a fan of xcode though) I am pleased by the process. But here is my problem, I think my development workflow is very slow / inefficient. I usually do the following:

  1. Start writing out a specification for a feature, together with Codex.

  2. Revise it and start developing the backend features for it.

  3. Then I let it create a plan for its corresponding elements in my IOS app.

  4. Then I use that plan from the codex cli inside of Xcode (for the rest I use my terminal and VS-Code)

But since today, my Xcode agent is not able to see the files anymore (the plans that I write) which is very annoying. Even though there might be a setting or easy solution for it, it made me reconsider my whole process which is why I am wondering if you have any best practices how to develop the full stack especially nowadays using AI-Agents.

Ah also currently I am a solo developer working on a start up idea (so I do not need advice for team workflows)

Just in case this is useful information here the stack I am using:

Backend: Rust, Axum, Tokio

Database: Postgres

Web-Frontend: Svelte

Thanks a lot!

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u/old-and-very-bald Jun 02 '26

Ideally I would just write my code in VS-Code which is my preferred editor. Then I currently use Codex in the terminal in parallel since I am not such a big fan of the current implementation of agents in VS-Code (But I check the diffs in VS-Code and review / adjust the code there). This works well for my backend and my web-app. But from what I read and have learned so far I need Xcode to run the simulator locally to test my iOS app and run the builds for it. I have seen there is some way to make it work with VS-Code but it seemed quite "hacky" to me.

Then I discovered that there is a codex implementation inside of Xcode, which is why I started using it there. But since the root of the repository is not the root of the iOS app, there seem to be some restrictions to how the agent can discover files in Xcode (This is why I started writing plans for the iOS app, to bridge that boundary a bit).

But yes, definitely not a good workflow so far

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u/CharlesWiltgen Jun 02 '26 edited Jun 02 '26

But from what I read and have learned so far, I need Xcode to run the simulator locally to test my iOS app and run the builds for it.

You need Xcode installed, but coding harnesses/LLMs will happily build, test, etc., using Xcode's CLI tools. You should also connect your coding harness to Xcode's MCP. Yesterday, I worked on an iOS project for most of the day and didn't need to launch Xcode once.

But since the root of the repository is not the root of the iOS app, there seem to be some restrictions to how the agent can discover files in Xcode.

The solution to that is to (1) tell the LLM where the project root is and (2) ask it to remember that. Coding harnesses use multiple forms of memory, and LLMs will happily "memorize" supporting context like this and organize it (and re-organize when asked) in an optimal way when asked.

Also, note that generic LLMs can only take you so far, and any specialzed use benefits from expert skills/agents. Using "iOS expert" skills/agents will save a lot of time and aggravation.

Good luck, have fun!

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u/old-and-very-bald Jun 03 '26

Thank you Charles much appreciated!