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GPT 6.1 Sol medium vs Opus 5

GPT 6.1 Sol medium leads on quality, cost and agent time: 0.2 points higher, 6.2× cheaper and 2.0× faster.

24 tasksData from

Stet score

GPT 6.1 Sol mediumRank 2 of 14

65.395% range 55.6–74.60.2 points higher

Opus 5Rank 3 of 14

65.195% range 54.8–74.9

A directional read: their 95% score ranges overlap.

Cost / task

GPT 6.1 Sol medium$1.106.2× cheaper
Opus 5$6.78

Agent time / task

GPT 6.1 Sol medium11.8 min2.0× faster
Opus 523.2 min

Task by task

GPT 6.1 Sol medium solved 2 tasks that Opus 5 didn’t, and Opus 5 solved 3 that GPT 6.1 Sol medium didn’t. Both solved 11; neither solved 8.

GPT 6.1 Sol medium only 2

  • stet-commit-f8ae1177Passed tests
  • stet-commit-342d0ac0Equivalent to the merged fix

Opus 5 only 3

  • stet-commit-f0caded9Passed 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.

All 24 compared tasks
Task by task
TaskGPT 6.1 Sol mediumOpus 5Solved by
stet-3169aefaPassed testsPassed testsBoth
stet-89dfbc27Passed testsPassed testsBoth
stet-b28f4fe7Passed testsPassed testsBoth
stet-232b50baPassed testsPassed testsBoth
stet-5276aa3fPassed testsPassed testsBoth
stet-commit-bbbbae09Passed testsPassed testsBoth
stet-15439c21Passed testsPassed testsBoth
stet-66762b4cPassed testsPassed testsBoth
stet-commit-f0caded9FailedPassed testsOpus 5 only
stet-commit-5d766ddeEquivalent to the merged fixEquivalent to the merged fixBoth
stet-43493c52Passed testsPassed testsBoth
stet-6f84e978Equivalent to the merged fixPassed testsBoth
stet-commit-f8ae1177Passed testsFailedGPT 6.1 Sol medium only
stet-2450ca2dFailedPassed testsOpus 5 only
stet-commit-342d0ac0Equivalent to the merged fixFailedGPT 6.1 Sol medium only
stet-commit-60a0e6c2FailedFailedNeither
stet-commit-5e075641FailedFailedNeither
stet-commit-2826765eFailedEquivalent to the merged fixOpus 5 only
stet-commit-a8716b88FailedFailedNeither
stet-commit-30506f8eFailedFailedNeither
stet-commit-87814583FailedFailedNeither
stet-commit-d2ab0c25FailedFailedNeither
stet-commit-e41c2e2dFailedFailedNeither
stet-commit-e928166fFailedFailedNeither

Side by side

Side by side
MetricGPT 6.1 Sol mediumOpus 5
Rank2 of 143 of 14
Stet score65.395% range 55.6–74.665.195% range 54.8–74.9
Solved13/2410 passed, 3 judged equivalent14/2412 passed, 2 judged equivalent
Passed review10/249/231 not recorded
Matched merged change10/2413/24
Cost / task$1.10$6.78
How cost was recordedestimated from tokensreported by its harness
Agent time / task11.8 min23.2 min
Ran inDaytona sandboxsandbox 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 6.1 Sol medium’s 7.

Changes up to 150 lines
GPT 6.1 Sol mediumOpus 5
Matched merged change7/1110/11
Passed review8/119/101 not recorded
Cost / task$0.47$1.50
Agent time / task5.8 min18.4 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 6.1 Sol medium’s 6.

Small fixes
GPT 6.1 Sol mediumOpus 5
Matched merged change6/77/7
Passed review5/77/7
Cost / task$0.42$0.99
Agent time / task5.3 min15.9 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.

Both matched the merged change on 3 of 13.

GPT 6.1 Sol medium passed review more often: 2 of 13 to Opus 5’s 0.

Larger changes
GPT 6.1 Sol mediumOpus 5
Matched merged change3/133/13
Passed review2/130/13
Cost / task$1.63$11.24
Agent time / task16.9 min27.2 min

From the leaderboard’s routing advice

  • Small fix: use Opus 5.
  • Small fix: to spend less, use GPT 6.1 Sol medium.
  • Larger change: use GPT 6.1 Sol medium.
  • Anything else: use GPT 6.1 Sol medium.

See which setup wins on your repo

Stet replays your merged PRs, scores quality above pass/fail, and delivers comparison reports through your agent.

Run it on your repo