Opus 5 leads on quality: 43.9 points higher; GPT 6 Luna low leads on cost and agent time: 127.0× cheaper and 3.4× faster.
24 tasks · Data from
Stet score
GPT 6 Luna lowRank 14 of 14
21.295% range 12.5–31.2
Opus 5Rank 3 of 14
65.195% range 54.8–74.943.9 points higher
Other setups
20406080even with the field
Their 95% score ranges don’t overlap.
Cost / task
GPT 6 Luna low$0.05127.0× cheaper
Opus 5$6.78
Agent time / task
GPT 6 Luna low6.9 min3.4× faster
Opus 523.2 min
Task by task
GPT 6 Luna low solved 0 tasks that Opus 5 didn’t, and Opus 5 solved 9 that GPT 6 Luna low didn’t. Both solved 5; neither solved 9.
GPT 6 Luna low
Opus 5
Passed tests
Equivalent to the merged fix
Failed
No change made
GPT 6 Luna low only 0
Opus 5 only 9
stet-5276aa3fPassed tests
stet-commit-bbbbae09Passed tests
stet-66762b4cPassed tests
stet-commit-f0caded9Passed tests
stet-commit-5d766ddeEquivalent to the merged fix
stet-43493c52Passed tests
stet-6f84e978Passed tests
stet-2450ca2dPassed tests
stet-commit-2826765eEquivalent to the merged fix
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. 1 of the 24 tasks is left out because one of the two has no scored result on it.
All 23 compared tasks
Task by task
Task
GPT 6 Luna low
Opus 5
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
Failed
Passed tests
Opus 5 only
stet-commit-bbbbae09
No change made
Passed tests
Opus 5 only
stet-15439c21
Passed tests
Passed tests
Both
stet-66762b4c
Failed
Passed tests
Opus 5 only
stet-commit-f0caded9
Failed
Passed tests
Opus 5 only
stet-commit-5d766dde
No change made
Equivalent to the merged fix
Opus 5 only
stet-43493c52
Failed
Passed tests
Opus 5 only
stet-6f84e978
Failed
Passed tests
Opus 5 only
stet-commit-f8ae1177
No change made
Failed
Neither
stet-2450ca2d
Failed
Passed tests
Opus 5 only
stet-commit-342d0ac0
Failed
Failed
Neither
stet-commit-5e075641
Failed
Failed
Neither
stet-commit-2826765e
Failed
Equivalent to the merged fix
Opus 5 only
stet-commit-a8716b88
Failed
Failed
Neither
stet-commit-30506f8e
Failed
Failed
Neither
stet-commit-87814583
Failed
Failed
Neither
stet-commit-d2ab0c25
Failed
Failed
Neither
stet-commit-e41c2e2d
Failed
Failed
Neither
stet-commit-e928166f
Failed
Failed
Neither
Side by side
Side by side
Metric
GPT 6 Luna low
Opus 5
Rank
14 of 14
3 of 14
Stet score
21.295% range 12.5–31.2
65.195% range 54.8–74.9
Solved
5/245 passed, 0 judged equivalent
14/2412 passed, 2 judged equivalent
Passed review
5/204 not recorded
9/231 not recorded
Matched merged change
5/204 not recorded
13/24
Cost / task
$0.05
$6.78
How cost was recorded
reported by its harness
reported by its harness
Agent time / task
6.9 min
23.2 min
Ran in
Daytona sandbox
sandbox not recorded
Where each setup is the better choice
The leaderboard’s readings on groups of tasks. Each group holds fewer tasks than the overall standings, so treat these as leads to test on your repo.
Changes up to 150 lines
11 tasks
11 tasks whose merged change was 2–149 lines in 1–2 files. The 7 small fixes below are among them.
Opus 5 matched the merged change more often: 10 of 11 to GPT 6 Luna low’s 5.
Changes up to 150 lines
GPT 6 Luna low
Opus 5
Matched merged change
5/11
10/11
Passed review
5/11
9/101 not recorded
Cost / task
$0.02
$1.50
Agent time / task
2.1 min
18.4 min
Small fixes
7 tasks
7 tasks whose instructions start with “Fix”. Their merged changes were 4–29 lines in 1–2 files.
Opus 5 matched the merged change more often: 7 of 7 to GPT 6 Luna low’s 5.
Small fixes
GPT 6 Luna low
Opus 5
Matched merged change
5/7
7/7
Passed review
5/7
7/7
Cost / task
$0.01
$0.99
Agent time / task
2.1 min
15.9 min
Larger changes
13 tasks
13 tasks whose merged change ran over 150 lines or more than 3 files: 113–1,420 lines in 2–19 files.
Larger changes
GPT 6 Luna low
Opus 5
Matched merged change
0/94 not recorded
3/13
Passed review
0/94 not recorded
0/13
Cost / task
$0.08
$11.24
Agent time / task
11.0 min
27.2 min
From the leaderboard’s routing advice
Small fix: use Opus 5.
See which setup wins on your repo
Stet replays your merged PRs, scores quality above pass/fail, and delivers comparison reports through your agent.