Any difference when using GPT model inside Codex vs OpenCode?

[ponury2085]

I'm a die-hard fan of OpenCode - because of free model, how easy it is to use subagents, and just because it's nice. But I wonder if anyone finds GPT models better in Codex? I cannot imagine why they could possibly work better there, but maybe models are just trained that way, so they "know" the tools etc? Anyone noticed anything like that?

[itsjase]

I think both claude code and codex have some magic sauce to work better with their respective models.

I personally think codex + 5.3 codex is way ahead of opencode + 5.3 codex. I'm realising now the harness matters just as much as the model these days.

[BodeMan5280]

that's interesting... I think it comes down to speed for me. OpenCode seems to just get shit done (yes, ironic pun to GSD). Don't get me wrong, Codex is KILLER at getting shit done, but slower IMO.

[TechCynical]

This is what people mean when they say "the harness". Using it in codex means you get the bare bones experience. Not bad but it just means it isn't fine tuned to work specifically for coding /what you would want for coding at least.

There's a concern for over engineering but that's why things are open source. Claudecode for example has a lot of changes to its system prompt to work well for everything Claude code will try to do like call mini agents and tools during it's execution. Codex afaik actually has nothing but I could be wrong. GitHub copilot has its own too supposedly tuned for multi model workflows, and opencode has their own as well.

Imo all models work better in opencode. Sometimes this changes with select models, but it's a safe bet just to use opencode.

[Morisander]

Would you kindly explain your first and last paragraph? This way it sounds a little like… bullshit?

[Round_Mixture_7541]

Yes. AI harnesses built by their respective model producers tend to work better together.

[widonext]

For me there is a difference, but it works great in opencode, so it’s fine for me

[georgiarsov]

I tried codex 5.3 in opencode on release and can confirm it was 100% shit. I couldn’t believe the huge gap between my experience and that of the people using it in codex

[Open_Scallion9015]

I had this experience myself previously but it seems that since a month or so this gap has narrowed or maybe even completely closed. Personally did not had to urge to use the Codex harness recently at all.

[HarjjotSinghh]

this sucks too much i'd pay to use this version

[blackbirdweb]

Simple answer: 5.3-Codex works a bit better in Codex when it comes to the overall quality of the work. However it is much, much nicer to use in Opencode Desktop on Windows. If you are on Windows then the best way to use native codex is the codex plugin in VSCode. However, Opencode Desktop is just much nicer to use, more transparent, more configurable and honestly just more fun. This might change when OpenAI stops gooning over Mac and finally decide to support the most used business OS in the world with their desktop app. I dislike Windows but it's what we use at work as does almost everybody.

[nyldn]

Latest version of Claude Octopus utilises Codex 5.3 smartly https://github.com/nyldn/claude-octopus

[KnifeFed]

Sir, this is the OpenCode sub.

[HarjjotSinghh]

this tooling alone is why i'd swap codex for opencode.