User says Opus 5 lags Fable on tricky tasks despite still being a strong model
doodlestein · x · 2026-07-27
The author says Opus 5 is not as smart as they first thought. While it is still a good model, it seems meaningfully worse than Fable once tasks get tricky. They initially suspected context rot, but even after accounting for that, they still find Fable stronger.
The main observation is behavioral: Opus 5 often produces a long list of mistakes it made during a session, which is better than being unaware of them, but Fable seems to avoid those mistakes in the first place by thinking longer before acting.
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