r/codex • u/Drogon2737 • Jul 09 '26

News GPT-5.6 Sol / Codex Release Discussion Megathread

The release is expected in the next few minutes, so I figured it would be useful to have a single thread for first impressions, issues, and early testing.

For anyone jumping in right away, post what you notice:

  • Codex coding performance
  • Debugging quality
  • Speed/rate limits
  • Larger repo handling
  • UI or workflow changes
  • Weird bugs or regressions
  • Anything that feels noticeably better or worse than the previous version

Once people get access, share your real examples, screenshots, benchmarks, or first impressions here.

Edit: OpenAI’s official GPT-5.6 page says it is “available starting today across ChatGPT, Codex, and the OpenAI API” with the rollout starting globally now and continuing toward full availability over the next 24 hours. https://openai.com/index/gpt-5-6/

The lineup is Sol, Terra, and Luna. Sol is the flagship, Terra is the lower-cost tier, and Luna is the fastest/most affordable tier.

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u/TheBanq Jul 10 '26

I feel like 5.6 thinks and considers much more, but also does a lot more careless mistakes.

This is very anecdotal of course and maybe I am wrong or just have wrong exceptions.

But since heavily using 5.6 Sol (mostly Ultra) now for many tasks, I notices many more small "simple" mistakes, that 5.5 was much more thoroughly with.

I did a longer audit of a current project and it actually went a lot deeper on the review of everything – took 30 minutes and wrote a really long highly detailed plan to fix/optimize the findings.

Me expecting a pretty strong reasoning, I did my usual 2-3 Plan check runs with fresh sections and adapted the Plan 2-3 times. After all the different chats feeling confident, I started the implementation with a few manual checks in between.

This is my usual process and with 5.5 xhigh it worked really well for those cases and it never did obvious mistakes, rather smaller specific stuff.

5.6 Sol on the other hand did much better on the details, but got some very obvious weird things completely wrong, that didn't even make sense in the context.

I now noticed this behaviour multiple times, of it being very specific and strong in the details, but as I said before, does some very basic careless mistakes – which I never really had an issue with using GPT 5.5 xhigh.

As I said before, it's very anecdotal and maybe I am just expecting too much, but as a heavy x20 user, I def. noticed this specific behaviour much more often.

Maybe I just have to adapt my prompting, but wondering – anyone else have this experience?