Re:Is Opus 5.5 nerfed? Thinking patterns changed on November 3
by seizethecheese on Monday November 09, 2026 @01:34PM
(#50429556)
We do, but it’s not definitive. We are building a battle system on top of OpenCode [1] and Opus 5.5 seems to have dropped since Nov 3rd.
If you calculate Elo only before 11/3 and compare to only after 11/3, the Elo is 52 points lower after. Unfortunately we are still in beta so this isn’t conclusive (confidence interval of -160 to +40).
If we do this calculation on all our models, Opus 5.5 is first in apparent drop. (Again, not definitive, but supports the conclusion.
If you calculate Elo only before 11/3 and compare to only after 11/3, the Elo is 52 points lower after. Unfortunately we are still in beta so this isn’t conclusive (confidence interval of -160 to +40).
If we do this calculation on all our models, Opus 5.5 is first in apparent drop. (Again, not definitive, but supports the conclusion.
[1]: https://agentduel.com/leaderboard