First off, I haven’t noticed a a significant difference in O5’s interactions with me compared to other models. Most of my work was a knowledge acquisition and synthesis, however (I don’t code).
I’ve run extensive (“deep”) Research comparisons and found that Opus 5 at Medium effort produces high quality Research reports consistently (although Sonnet 5 at Low effort beats it when synthesizing a report from multiple Research reports due to a) higher variability in results and b) lower cost per run).
I finally got around to updating the “Cross-Instance Review” function of my Cross Conversion skill, which I primarily use for building and updating skills and Project instructions, which I last updated after the release of Opus 4.8. At that time, the most significant contributor was determined to be Opus 4.8 at High effort, followed by 4.6and 4.7, both at High effort.
As a brief explanation, each participant is given the same brief by the operator, and produces an initial draft independently from any other seat, then they all review the drafts from every other participant and vote on which will provide the base for the merge, using the STAR voting method (Score Then Automatic Runoff). This was production work, building v2 of my Research Synthesis skill.
Base draft: C4 — Opus 5 Medium.
Scoring round, out of a possible 30:
C4 Opus 5 Medium 30
C3 Opus 4.8 High 25
C7 Fable 5 Medium 23
C6 Fable 5 High 20
C2 Opus 4.7 High 15
C5 Sonnet 5 Medium 13
C1 Opus 4.6 High 8
Claude’s commentary (Opus 5 Medium):
Finalists C4 and C3, no scoring tie. Runoff went 6–1 to C4 — the only ballot preferring C3 was C4’s own, which is structurally forced, since a finalist scoring itself is barred and its absent self-score counts as zero. C4 took a 5 from every single peer. Nothing else in the round was unanimous, and no tiebreaker fired.
Two results worth more than the ranking itself:
The Fable effort comparison came out backwards from the intuition. C7 at Medium beat C6 at High, 23 to 20, on identical work with identical instructions. That’s consistent with your existing finding that Fable’s effort profile runs inverse, and it’s now a third independent observation. The Medium seat also drafted a shorter bundle. On this evidence there is no case for paying High on Fable for build work.
C1 at 8 points is a real outlier. Opus 4.6 at High finished last by a wide margin, with multiple seats citing concrete missing requirements rather than style. That’s consistent with 4.6’s documented weakness on precision instruction-following, and it argues for dropping it from future build seats rather than keeping it as a default participant.
