Agreed, had the same experience. Codex feels lazy - I have to explicitly tell it to research existing code before it stops giving hand-wavy answers. Doc lookup is particularly bad; I even gave it access to a Context7 MCP server for documentation and it barely made a difference. The personality also feels off-putting, even after tweaking the experimental flag settings to make it friendlier.
For people suggesting it’s a skill issue: I’ve been using Claude Code for the past 6 months and I genuinely want to make Codex work - it was highly recommended by peers and friends. I’ve tried different model settings, explicitly instructed it to plan first and only execute after my approval, tested it on both Python and TypeScript backend codebases. Results are consistently underwhelming compared to Claude Code.
Claude Code just works for me out of the box. My default workflow is plan mode - a few iterations to nail the approach, then Claude one-shots the implementation after I approve. Haven’t been able to replicate anything close to that with Codex
+1 to this. Been using Codex the last few months, and this morning I asked it to plan a change. It gave me generic instructions like 'Check if you're using X' or 'Determine if logic is doing Y' - I was like WTF.
Curious, are you doing the same planning with Codex out-of-band or otherwise? In order to have the same measurable outcome you'd need to perhaps use Codex in a plan state (there's experimental settings - not recommended) or other means (explicit detailed -reusable- prompt for planning a change). It's a missing feature if your preference is planning in CLI (I do not prefer this).
You are correct in that this mode isn't "out of the box" as it is with Claude (but I don't use it in Claude either).
My preference is to have smart models generate a plan with provided source. I wrote (with AI) a simple python tool that'll filter a codebase and let me select all files or just a subset. I then attach that as context and have a smart model with large context (usually Opus, GPT-5.2, and Gemini 3 Pro in parallel), give me their version of a plan. I then take the best parts of each plan, slap it into a single markdown and have Codex execute in a phased manner. I usually specify that the plan should be phased.
I prefer out-of-CLI planning because frankly it doesn't matter how good Codex or Claude Code dive in, they always miss something unless they read every single file and config. And if they do that, they tip over. Doing it out of band with specialized tools, I can ensure they give me a high quality plan that aligns with the code and expectations, in a single shot (much faster).
Then Claude/Codex/Gemini implement the phased plan - either all at once - or stepwise with me testing the app at each stage.
But yeah, it's not a skill issue on your part if you're used to Plan -> Implement within Claude Code. The Experimental /collab feature does this but it's not supported and more experimental than even the experimental settings.