[thombles]

Today I was a few hours into chasing down a very tricky timing-dependent bug with GPT 5.5 and we were starting to go into circles. I noticed Opus 4.8 had showed up in GitHub Copilot so I switched over and pointed it at my notes so far. Another hour of steady progress and it tracked it down to some missing synchronisation in an upstream library which was occasionally corrupting a linked list. N=1 but worth every one of those rather expensive 15x requests today. 15x... yeah.

[zuzululu]

That is interesting, are you saying that GPT 5.5 could not fix an issue that Opus 4.8 did? Are you sure this is not due to fresh context?

I do notice this tendency for 5.5 to go in endless circles.

[thombles]

That's my initial experience, yes. It's hard to compare these things cleanly of course. I went through several new contexts on GPT and it just couldn't get traction -- it became hard to keep it focused on "yes there's clearly a race but what actual persistent state got broken"? It just wanted to change the thread priorities so that the problem didn't occur and kept doubling down on that as the solution. Opus made some missteps too but it responded well to my corrections - 2 or 3 significant ones along the way - and it was prepared to keep digging on my exact goal until it found the real issue.

[zuzululu]

I think your anecdotes lines up a lot with what I've seen online, I am noticing a lot of codex users in particular appears to have discovered Opus 4.8 seems to make them very happy.

I am going to subscribe to Claude and try this out myself. I'm going to be very honest that I am currently finding codex to be very lacking, not from its generous usage limits but just the sheer number of repeated prompts to prevent its inclinations in getting stuck in a spiral, one which is very hard to get out of once it digs itself into a hole (I've had it refuse instructions despite desperate pleas and starting a new convo appears to fix it and hence why I wasn't sure if this Opus 4.8 issue was of fresh context but it appears to be very capable in ways that codex isn't).

Thanks for sharing your anecdote!

[tornikeo]

GPT 5.5 feels worse than 5.4 for the last few weeks. Again N=1, but would be interested to see how opus 4.8 and gpt 5.4 match

[CamelCaseName]

You know what that means... 5.6 is dropping soon