SWE Atlas - Test Writing: leaderboard

SWE Atlas Test Writing evaluates coding agents on writing production-grade tests for specific behaviors in real-world software repositories.

Metric: Score. Source: labs.scale.com. Source: scale.com. 24 models tracked.

Top models

#ModelScoreOverall rank
1Claude Fable 5.1 (xHigh)67.04#9 (Claude Fable 5.1)
2Claude Opus 5 (xHigh)62.22#12 (Claude Opus 5)
3Claude Fable 5 (xHigh)55.6#16 (Claude Fable 5)
4Gemini 3.8 Flash53.7#21
5GPT-6 Astra (xHigh)50.74#6 (GPT-6 Astra)
6Claude Opus 4.8 (xHigh)49.63#37 (Claude Opus 4.8)
7GPT-5.6 Sol (xHigh)45.9#19 (GPT-5.6 Sol)
8GPT-5.5 (xHigh)42.59#31 (GPT-5.5)
9GLM-5.241.48#73
10Muse Spark 1.1 (xHigh)41.48#52 (Muse Spark 1.1)
11GPT-5.4 (xHigh)40#79 (GPT-5.4)
12GPT-5.3 Codex (xHigh)38.98#69 (GPT-5.3 Codex)
13Claude Opus 4.738.52#49
14Claude Opus 4.636.08#63
15Claude Sonnet 4.631.76#90

No result here: #3 Claude Opus 5.5, #7 GPT-6.1 Sol, #8 Gemini 4 Argon.

Interactive version: theaggregate.ai/benchmark?slug=swe-atlas-test-writing · How It Works · Data refreshed daily, snapshot 2026-10-20.