Where do these coding results come from?

Both coding agents worked the same 24 merged changes from the private Stet-AI/stet repository, each in the real repo as it was before the change. The repo’s tests and judges graded every patch against the merged change; no public benchmark scores are used.

Are reasoning settings combined into one model score?

No. Each effort pairing keeps its own recorded quality call, head-to-head record, cost and agent time. Incompatible scores are never averaged.

Haiku 5.5 vs SWE-2 Max

Haiku 5.5 faster in both pairings. SWE-2 Max leads on quality in every pairing; directional at this sample size. 2 pairings; 24 merged changes in Stet-AI/stet. Compare the individual calls below to choose which setup to investigate.

What this comparison is

1 real repositoryStet-AI/stet, private; not public benchmark scores
24 merged changeseach run end to end by the coding agent from the repo as it was before the change
Graded against the merged changeby the repo’s own tests and by judges comparing each patch with it
Quality, cost and timea smaller sample than public benchmarks, but real agent work on a real codebase

Compare coding models Low vs high vs xhigh/max reasoning for coding agents

Recorded setup pairings

Each row is a separate recorded comparison. Scores are not pooled or averaged across effort settings. W/D/L means wins, draws and losses; undecided judgments remain undecided.

Stet score: A setup’s average chance of beating another setup on a task, from 0 to 100; 50 is even with the field.

Setup pairing	Recorded quality call and record	Quality evidence	Cost per task	Agent time per task
Haiku 5.5 max vs SWE-2 Max highHaiku 5.5 max · max reasoningSWE-2 Max high · high reasoning23/24 tasks observed by both setups.	SWE-2 Max high leads on quality, 5–2 head to head with 15 tied and 2 undecided (directional at this sample size); Haiku 5.5 max leads on agent time: 1.2× faster; SWE-2 Max high’s cost wasn’t recorded.Head to head, SWE-2 Max high won 5, tied 15 and lost 2 against Haiku 5.5 max, with 2 undecided.	Directional lead at this sample size 5–2 head to head, 15 tiedHaiku 5.5 max: 48.2 (95% range 38.8–58.1)SWE-2 Max high: 58.0 (95% range 49.7–66.8)	Haiku 5.5 max: $0.78 SWE-2 Max high: not recorded	Haiku 5.5 max: 58.4 min SWE-2 Max high: 68.3 min
Haiku 5.5 low vs SWE-2 Max highHaiku 5.5 low · low reasoningSWE-2 Max high · high reasoning24/24 tasks observed by both setups.	SWE-2 Max high leads on quality: won 7, tied 15, lost 1, 1 undecided head to head; Haiku 5.5 low leads on agent time: 6.9× faster; SWE-2 Max high’s cost wasn’t recorded.Head to head, SWE-2 Max high won 7, tied 15 and lost 1 against Haiku 5.5 low, with 1 undecided.Not yet conclusive across all 136 comparisons on the board.	Clear lead 7–1 head to head, 15 tiedHaiku 5.5 low: 44.7 (95% range 39.5–49.1)SWE-2 Max high: 58.0 (95% range 49.7–66.8)	Haiku 5.5 low: $0.06 SWE-2 Max high: not recorded	Haiku 5.5 low: 9.9 min SWE-2 Max high: 68.3 min

Setup pairing

Recorded quality call and record

Quality evidence

Cost per task

Agent time per task

Haiku 5.5 max vs SWE-2 Max highHaiku 5.5 max · max reasoningSWE-2 Max high · high reasoning23/24 tasks observed by both setups.

SWE-2 Max high leads on quality, 5–2 head to head with 15 tied and 2 undecided (directional at this sample size); Haiku 5.5 max leads on agent time: 1.2× faster; SWE-2 Max high’s cost wasn’t recorded.Head to head, SWE-2 Max high won 5, tied 15 and lost 2 against Haiku 5.5 max, with 2 undecided.

Directional lead at this sample size
5–2 head to head, 15 tiedHaiku 5.5 max: 48.2 (95% range 38.8–58.1)SWE-2 Max high: 58.0 (95% range 49.7–66.8)

Haiku 5.5 max: $0.78

SWE-2 Max high: not recorded

Haiku 5.5 max: 58.4 min

SWE-2 Max high: 68.3 min

Haiku 5.5 low vs SWE-2 Max highHaiku 5.5 low · low reasoningSWE-2 Max high · high reasoning24/24 tasks observed by both setups.

SWE-2 Max high leads on quality: won 7, tied 15, lost 1, 1 undecided head to head; Haiku 5.5 low leads on agent time: 6.9× faster; SWE-2 Max high’s cost wasn’t recorded.Head to head, SWE-2 Max high won 7, tied 15 and lost 1 against Haiku 5.5 low, with 1 undecided.Not yet conclusive across all 136 comparisons on the board.

Clear lead
7–1 head to head, 15 tiedHaiku 5.5 low: 44.7 (95% range 39.5–49.1)SWE-2 Max high: 58.0 (95% range 49.7–66.8)

Haiku 5.5 low: $0.06

SWE-2 Max high: not recorded

Haiku 5.5 low: 9.9 min

SWE-2 Max high: 68.3 min

Questions about these results

Which is better for coding, Haiku 5.5 or SWE-2 Max?: Haiku 5.5 faster in both pairings. SWE-2 Max leads on quality in every pairing; directional at this sample size. 2 pairings; 24 merged changes in Stet-AI/stet. Compare the individual calls below to choose which setup to investigate.
Where do these coding results come from?: Both coding agents worked the same 24 merged changes from the private Stet-AI/stet repository, each in the real repo as it was before the change. The repo’s tests and judges graded every patch against the merged change; no public benchmark scores are used.
Are reasoning settings combined into one model score?: No. Each effort pairing keeps its own recorded quality call, head-to-head record, cost and agent time. Incompatible scores are never averaged.