Updated
Which AI model writes the most business-logic bugs?
As of Nov 14, 2026, Claude Opus 5.5 had the highest rate of business-logic bugs (1.53, 53% above the all-model rate), statistically tied with Claude Sonnet 5.5. GPT-6.1 Sol had the lowest (0.60, 40% below average), statistically tied with GPT-6 Astra, Claude Fable 5.1, and Claude Sonnet 5.5.
| Rank | Model | Rate |
|---|---|---|
| 1= (statistically tied) | GPT-6.1 Sol | 0.60 |
| 2= (statistically tied) | GPT-6 Astra | 0.75 |
| 3= (statistically tied) | Claude Fable 5.1 | 0.79 |
| 4= (statistically tied) | Claude Sonnet 5.5 | 1.19 |
| 5= (statistically tied) | Claude Opus 5.5 | 1.53 |
1.00 = all-model rate · lower is better · = statistically tied