Some thoughts about GPT-5.6-Sol after ~30B tokens:
Sol is the most OCD model Iโve used thus far. It very frequently gets one-shotted by random nits in the codebase and writes a bunch of tests to fix it. Even with fast mode, itโs incredibly slow to do this kind of iterative development, especially when builds take really long. This by itself is not a bad thing, but the worst part is that after 2 compactions, itโs chasing the nitpick / useless goals I never told it to accomplish, rather than the main task. This behavior is so bad, I thought I was messing something up and tried codex, pi, and opencode to figure out if itโs a harness issue, but there is no meaningful difference between the three, which leads me to believe this is a model problem.
AI code has this weird delayed release effect. Youโll only notice slop code 2 dev cycles into a codebase when you spend more time fighting with the code and on refactors than on shipping features. Itโs possible that sol is better than 5.5 a couple cycles in, but tbd.
My file deletion experience has also been similar to others: this is a dangerous model to let loose without guardrails. For instance, when performing a routine container upgrade, it accidentally printed out an env secret, then panicked and rotated ALL secrets (this is internal so not public facing, which was also documented), and proceeded to break everything, spending an extra hour fixing everything and redeploying everything else to use the new secrets. It also gets rid of files it doesnโt like. I have no idea why this is, but I think something about the reward model rewarded bookkeeping.
Writing is another problem. 5.6 has a huge context bleed effect. It does not know how to write documentation and starts putting the specs in the documentation. If I ask it to develop a user sandbox for isolation, and also ask it to write documentation, it starts talking about specs and sandboxes in user-facing docs, which makes no sense. Fable is somehow much, much smarter in this regard. Frontend design has also not gotten better. Fable is still one generation ahead here.
Overall, as a huge 5.5 user, I am not convinced that sol is a meaningful upgrade. Itโs possible my practices need to change, but unfortunately it feels like Iโm spending longer fighting with 5.6 than I did with 5.5. Itโs like the model is so SO smart, but so hard to work with, compared to fable and even grok4.5 surprisingly. Itโs clearly intelligent, but also just doesnโt care about what I ask it to do? (Is this supposed to be AGI feels like?) I hope the codex team fixes what possibly is a bad harness setup, because the benchmark numbers show a very different story from what Iโm seeing while using the model.
@pvncher Why don't you just let the users customize their sub agent like in opencode?
I don't understand why codex and cc limit sub agents like that, you already have the blueprint from the @opencode project. We can write our own "scout"/"advisor"/"playwright driver" etc
@pvncher I told it to run tests and commit when it's done, and it failed. 5.6 sol is the first model that struggles to follow explicit instructions.
I also told it to add "don't use the new browser ever" (the one that asks for approvals) to memories. It took 4 tries!
@pvncher My system instructions are short and include clear and explicit instructions to run tests and commit changes.
Every model including 5.5 complies.
5.6 is the first one that didnt, plus, it scope creeped the task and made things worse.
Most disappointing model ever
@DavidOndrej1 Most disappointing model release ever for me. Sol completely ignores clear instructions, starts every side quest ever, generally annoying and lame.