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Haiku 5.5 max vs SWE-2 Max

SWE-2 Max leads on quality: 7.8 points higher; Haiku 5.5 max leads on agent time: 1.2× faster; SWE-2 Max’s cost wasn’t recorded.

24 tasksData from

Stet score

Haiku 5.5 maxRank 6 of 14

58.695% range 47.5–69.0

SWE-2 MaxRank 1 of 14

66.495% range 56.8–75.47.8 points higher

A directional read: their 95% score ranges overlap.

Cost / task

Haiku 5.5 max$3.85
SWE-2 Maxnot recorded

Agent time / task

Haiku 5.5 max58.4 min1.2× faster
SWE-2 Max68.3 min

Task by task

Haiku 5.5 max solved 1 task that SWE-2 Max didn’t, and SWE-2 Max solved 4 that Haiku 5.5 max didn’t. Both solved 11; neither solved 7.

Haiku 5.5 max only 1

  • stet-commit-f8ae1177Passed tests

SWE-2 Max only 4

  • stet-232b50baPassed tests
  • stet-66762b4cPassed 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. 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
TaskHaiku 5.5 maxSWE-2 MaxSolved by
stet-3169aefaPassed testsPassed testsBoth
stet-89dfbc27Passed testsPassed testsBoth
stet-b28f4fe7Passed testsPassed testsBoth
stet-232b50baFailedPassed testsSWE-2 Max only
stet-5276aa3fPassed testsPassed testsBoth
stet-commit-bbbbae09Passed testsPassed testsBoth
stet-15439c21Passed testsEquivalent to the merged fixBoth
stet-66762b4cFailedPassed testsSWE-2 Max only
stet-commit-f0caded9Passed testsPassed testsBoth
stet-commit-5d766ddeEquivalent to the merged fixPassed testsBoth
stet-43493c52FailedFailedNeither
stet-6f84e978Equivalent to the merged fixPassed testsBoth
stet-commit-f8ae1177Passed testsFailedHaiku 5.5 max only
stet-2450ca2dPassed testsPassed testsBoth
stet-commit-342d0ac0Equivalent to the merged fixEquivalent to the merged fixBoth
stet-commit-5e075641FailedPassed testsSWE-2 Max only
stet-commit-2826765eFailedFailedNeither
stet-commit-a8716b88FailedEquivalent to the merged fixSWE-2 Max only
stet-commit-30506f8eFailedFailedNeither
stet-commit-87814583FailedFailedNeither
stet-commit-d2ab0c25FailedFailedNeither
stet-commit-e41c2e2dFailedFailedNeither
stet-commit-e928166fFailedFailedNeither

Side by side

Side by side
MetricHaiku 5.5 maxSWE-2 Max
Rank6 of 141 of 14
Stet score58.695% range 47.5–69.066.495% range 56.8–75.4
Solved12/249 passed, 3 judged equivalent16/2413 passed, 3 judged equivalent
Passed review9/222 not recorded8/24
Matched merged change10/222 not recorded13/24
Cost / task$3.85not recorded
How cost was recordedreported by its harness on 23, estimated from tokens on 1not recorded
Agent time / task58.4 min68.3 min
Ran inDaytona sandboxDaytona sandbox

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.

Changes up to 150 lines
Haiku 5.5 maxSWE-2 Max
Matched merged change7/101 not recorded8/11
Passed review7/101 not recorded7/11
Cost / task$1.18not recorded
Agent time / task36.3 min22.1 min

Small fixes

7 tasks

7 tasks whose instructions start with “Fix”. Their merged changes were 4–29 lines in 1–2 files.

Both matched the merged change on 5 of 7.

Small fixes
Haiku 5.5 maxSWE-2 Max
Matched merged change5/75/7
Passed review5/75/7
Cost / task$1.15not recorded
Agent time / task34.6 min21.5 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
Haiku 5.5 maxSWE-2 Max
Matched merged change3/121 not recorded5/13
Passed review2/121 not recorded1/13
Cost / task$6.11not recorded
Agent time / task77.1 min107.3 min

See which setup wins on your repo

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