Which has fewer bugs, Claude Fable 5.1 or GPT-5.6 Sol?

GPT-5.6 Sol had 37% fewer counted bugs per line than Claude Fable 5.1 (0.73 vs 1.17). GPT-5.6 Sol ranks #1 of 7 and Claude Fable 5.1 #4.

Which is used more, Claude Fable 5.1 or GPT-5.6 Sol?

Claude Fable 5.1, with 19.4% of the AI-written code reviewed by cubic in the week of Sep 14, 2026, against 7.2% for GPT-5.6 Sol.

Updated Sep 26, 2026

GPT-5.6 Sol had 37% fewer counted bugs per line than Claude Fable 5.1 (0.73 vs 1.17).

Claude Fable 5.1 and GPT-5.6 Sol compared on relative bug rate, by coding agent, bug type, and language, and on price and usage.
Bug rate
	Claude Fable 5.1	GPT-5.6 Sol
Relative bug rate	1.17	0.73
Rank	#4 of 7	#1 of 7
Details
Share of AI-written code, week of Sep 14	19.4%	7.2%

1.00 = average · lower is better

Which has fewer bugs, Claude Fable 5.1 or GPT-5.6 Sol?: GPT-5.6 Sol had 37% fewer counted bugs per line than Claude Fable 5.1 (0.73 vs 1.17). GPT-5.6 Sol ranks #1 of 7 and Claude Fable 5.1 #4.
Which is used more, Claude Fable 5.1 or GPT-5.6 Sol?: Claude Fable 5.1, with 19.4% of the AI-written code reviewed by cubic in the week of Sep 14, 2026, against 7.2% for GPT-5.6 Sol.