Muse Wonder Full low vs Opus 4.8 medium

No clear quality winner: Muse Wonder Full low won 14, Opus 4.8 medium won 5, 1 tied, 4 undecided; Muse Wonder Full low leads on cost and agent time: 2.5× cheaper and 1.1× faster.

24 tasksData from October 29, 2026

Stet score

Muse Wonder Full lowmuse · low reasoningRank 1 of 16

70.495% range 58.6–81.231.2 points higher

Opus 4.8 mediumclaude-code · medium reasoningRank 12 of 16

39.295% range 29.0–49.7

Other setups

GPT 5.6 Luna max

70.3

SWE-2 Max high

64.3

GPT 6.1 Sol medium

62.5

Opus 5 medium

62.3

Grok 4.7 high

60.7

Pareto 26.9 medium

57.1

Haiku 5.5 max

55.5

GPT 6 Sol medium

55.4

GPT 6 Luna max

47.4

DeepSeek V4.1 Flash max

45.9

Haiku 5.5 low

38.9

Muse Spark 1.3 high

31.9

GLM 5.3 Flash high

29.0

GPT 6 Luna low

19.9

Their 95% score ranges don’t overlap.

Cost / task

Muse Wonder Full low$2.852.5× cheaper

Opus 4.8 medium$7.05

Agent time / task

Muse Wonder Full low21.6 min1.1× faster

Opus 4.8 medium23.3 min

Quality

Head-to-head matchups

Muse Wonder Full low won14

Tied14 undecided

Opus 4.8 medium won5

Muse Wonder Full low’s win share 73%, 95% range 53–90%Ties are within judge noise.

Task by task

Muse Wonder Full low solved 2 tasks that Opus 4.8 medium didn’t, and Opus 4.8 medium solved 2 that Muse Wonder Full low didn’t. Both solved 10; neither solved 6.

Muse Wonder Full low only 2

stet-2450ca2dPassed tests
stet-commit-e928166fEquivalent to the merged fix

Opus 4.8 medium only 2

stet-6f84e978Passed tests
stet-commit-60a0e6c2Passed tests

A task counts as solved when its tests passed or a judge found the fix equivalent to the merged change, as in the leaderboard’s Solved column. Stet score also weighs code quality, so it can order the two differently. 4 of the 24 tasks are left out because one of the two has no scored result on them.

All 20 compared tasks

Task by task
Task	Muse Wonder Full low	Opus 4.8 medium	Solved by
`stet-3169aefa`	Passed tests	Passed tests	Both
`stet-89dfbc27`	Passed tests	Passed tests	Both
`stet-b28f4fe7`	Passed tests	Passed tests	Both
`stet-232b50ba`	Passed tests	Passed tests	Both
`stet-5276aa3f`	Passed tests	Passed tests	Both
`stet-commit-bbbbae09`	Passed tests	Passed tests	Both
`stet-66762b4c`	Equivalent to the merged fix	Passed tests	Both
`stet-15439c21`	Passed tests	Passed tests	Both
`stet-commit-5d766dde`	Equivalent to the merged fix	Equivalent to the merged fix	Both
`stet-43493c52`	Passed tests	Passed tests	Both
`stet-6f84e978`	Failed	Passed tests	Opus 4.8 medium only
`stet-2450ca2d`	Passed tests	Failed	Muse Wonder Full low only
`stet-commit-342d0ac0`	Failed	Failed	Neither
`stet-commit-60a0e6c2`	Failed	Passed tests	Opus 4.8 medium only
`stet-commit-5e075641`	Failed	Failed	Neither
`stet-commit-a8716b88`	Failed	Failed	Neither
`stet-commit-e928166f`	Equivalent to the merged fix	Failed	Muse Wonder Full low only
`stet-commit-30506f8e`	Failed	Failed	Neither
`stet-commit-d2ab0c25`	Failed	Failed	Neither
`stet-commit-e41c2e2d`	Failed	Failed	Neither

Side by side

Side by side
Metric	Muse Wonder Full low	Opus 4.8 medium
Harness	muse	claude-code
Reasoning effort	low	medium
Rank	1 of 16	12 of 16
Stet score	70.495% range 58.6–81.2	39.295% range 29.0–49.7
Solved	12/249 passed, 3 judged equivalent	13/2411 passed, 2 judged equivalent
Cost / task	$2.85	$7.05
Agent time / task	21.6 min	23.3 min

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About this data

24 tasks, each a merged change replayed from the repo as it was just before the merge.
Data from October 29, 2026.
Both setups come from the same leaderboard run of 16 setups: bmk_d4ba310fdf50db4ccb2092e3.

See all 16 setups on the leaderboard How Stet measures