Challenges With Codex - Comparison with GitHub Copilot and Cursor

Codex
1

I’m having some trouble developing code with Codex. I am using Codex in VS Code Insiders.

The primary issue is Codex tends to insert /r/n characters throughout code files. Then the code will not build.

Is there a way to get it to stop doing this?

Also, I think there needs to be a middle-ground between Agent mode and Agent (full access).

With agent mode, I am prompted for every single command to run. This would have me clicking “Approve” all day long. For Agent (full access), it’s almost too much access. I need a solution that is somewhere in between the two.

Finally, no matter which Codex model I pick, the editing capability seems to be about 10% as efficient as GitHub Copilot or Cursor using the premium models within those IDEs.

I want to be able to use Codex, but each time I give it a shot it is inefficiently making edits that are off and don’t even compile. For example, I waited 30 minutes for Codex to struggle through making edits that didn’t compile - malformed html tags, erroneous \r\n characters. GitHub Copilot and Cursor are able to make the same changes correctly in 10% of the time that Codex is taking on low, medium or high models.

At this point, Codex isn’t usable. Please help.

2

I am having same issue. It likely an issue with the powershell commands, I’m not sure what it’s like on mac os but i’m having issue on windows 11.

And then it was putting like alien characters in code like ‘aaaaAAaaaaAaaAaaAA” but different variants of “a” or something.

3

Which IDE are you using @Jack_Devoy ?

I am also on Windows 11.

4

I am using cursor. With codex extension. i’ve also tested in terminal and i think there was thge same issue.

I am usign vscode for another project atm but i don’t think i’ve seen it yet but i’m still building out react nativie app. So it may be due to it searching through large codebase and a tool call it uses to search and edit.

It could also be how cursor ide wraps vscode but i can’t confirm if issue is just on cursor yet.

5

I’m having the issues in VS Code, so it isn’t only Cursor.

6

I am on Windows 10 with Cursor, and usually the errors lie also in the Power Shell Terminal Commands, although not quite as often as you described

7

Did you say, Windows….. Of course you mean Linux right? No one would willfully subject themselves to Windows. I assume that your Linux machine is temporarily broken, and you’ve been forced to borrow a non-developer friends computer?

I had a lot of similar problems with it running powershell commands that all went away when I took Linux’s hand and sailed off into the developer sunset.

1 Like
8

Same here. My experience so far comparing Visual Studio Code with the Codex Extension vs. Visual Studio Code with GitHub Copilot:

  • Codex is noticeably slower.

  • There’s no way to preview or track changes made by the agent (no Undo/Apply workflow like in Copilot), which makes it hard to see what actually changed between prompts.
    → Edited: This seems to be working now.

  • I also ran into issues with \r\n characters (as mentioned earlier) in Codex.

  • I tested with gpt-5-codex-medium.

Overall, given these issues, it doesn’t feel usable in its current state. Would be great to see some improvements in the near future.

Now that we can also use the new Codex model within GitHub Copilot:

Has anyone tried Visual Studio Code + GitHub Copilot (with gpt-5-codex) and compared it directly to using Codex itself (same model)?strong text

9

Yes GPT-5-codex in GitHub Copilot or Cursor works quite well. Give that a try.