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Haiku 5.5 low vs SWE-2 Max high

No clear quality winner: SWE-2 Max high won 12, Haiku 5.5 low won 5, 7 tied; Haiku 5.5 low leads on agent time: 6.9× faster; SWE-2 Max high’s cost wasn’t recorded.

24 tasksData from

Stet score

Haiku 5.5 lowclaude-code · low reasoningRank 13 of 16

38.995% range 32.6–45.4

SWE-2 Max highdevin · high reasoningRank 3 of 16

64.395% range 54.3–73.925.4 points higher

Their 95% score ranges don’t overlap.

Cost / task

Haiku 5.5 low$0.25
SWE-2 Max highnot recorded

Agent time / task

Haiku 5.5 low9.9 min6.9× faster
SWE-2 Max high68.3 min

Quality

Head-to-head matchups

Haiku 5.5 low won5

Tied7

SWE-2 Max high won12

SWE-2 Max high’s win share 70%, 95% range 55–85%Ties are within judge noise.

Task by task

Haiku 5.5 low solved 1 task that SWE-2 Max high didn’t, and SWE-2 Max high solved 6 that Haiku 5.5 low didn’t. Both solved 10; neither solved 7.

Haiku 5.5 low only 1

  • stet-43493c52Passed tests

SWE-2 Max high only 6

  • stet-6f84e978Passed tests
  • stet-2450ca2dPassed tests
  • stet-commit-342d0ac0Equivalent to the merged fix
  • stet-commit-60a0e6c2Passed tests
  • stet-commit-5e075641Passed tests
  • stet-commit-a8716b88Equivalent 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
TaskHaiku 5.5 lowSWE-2 Max highSolved 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-66762b4cEquivalent to the merged fixPassed testsBoth
stet-15439c21Equivalent to the merged fixEquivalent to the merged fixBoth
stet-commit-5d766ddeEquivalent to the merged fixPassed testsBoth
stet-43493c52Passed testsFailedHaiku 5.5 low only
stet-commit-f0caded9Equivalent to the merged fixPassed testsBoth
stet-6f84e978FailedPassed testsSWE-2 Max high only
stet-2450ca2dFailedPassed testsSWE-2 Max high only
stet-commit-342d0ac0FailedEquivalent to the merged fixSWE-2 Max high only
stet-commit-f8ae1177FailedFailedNeither
stet-commit-60a0e6c2FailedPassed testsSWE-2 Max high only
stet-commit-5e075641FailedPassed testsSWE-2 Max high only
stet-commit-2826765eFailedFailedNeither
stet-commit-a8716b88FailedEquivalent to the merged fixSWE-2 Max high only
stet-commit-e928166fFailedFailedNeither
stet-commit-30506f8eFailedFailedNeither
stet-commit-87814583FailedFailedNeither
stet-commit-d2ab0c25FailedFailedNeither
stet-commit-e41c2e2dFailedFailedNeither

Side by side

Side by side
MetricHaiku 5.5 lowSWE-2 Max high
Harnessclaude-codedevin
Reasoning effortlowhigh
Rank13 of 163 of 16
Stet score38.995% range 32.6–45.464.395% range 54.3–73.9
Solved11/247 passed, 4 judged equivalent16/2413 passed, 3 judged equivalent
Cost / task$0.25not recorded
Agent time / task9.9 min68.3 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 .
  • Both setups come from the same leaderboard run of 16 setups: bmk_d4ba310fdf50db4ccb2092e3.

See all 16 setups on the leaderboardHow Stet measures