Which has fewer bugs, Claude Fable 5.1 or GPT-6 Astra?

Claude Fable 5.1 (1.17) and GPT-6 Astra (1.16) are statistically tied on Bug Bench. GPT-6 Astra ranks #3 of 7 and Claude Fable 5.1 #4.

Which is used more, Claude Fable 5.1 or GPT-6 Astra?

GPT-6 Astra, with 19.6% of the AI-written code reviewed by cubic in the week of Sep 14, 2026, against 19.4% for Claude Fable 5.1.

Updated Sep 26, 2026

Claude Fable 5.1 (1.17) and GPT-6 Astra (1.16) are statistically tied on Bug Bench.

Claude Fable 5.1 and GPT-6 Astra compared on relative bug rate, by coding agent, bug type, and language, and on price and usage.
Bug rate
	Claude Fable 5.1	GPT-6 Astra
Relative bug rate(statistically tied)	1.17	1.16
Rank	#4 of 7	#3 of 7
Details
Share of AI-written code, week of Sep 14	19.4%	19.6%

1.00 = average · lower is better · = statistically tied

Which has fewer bugs, Claude Fable 5.1 or GPT-6 Astra?: Claude Fable 5.1 (1.17) and GPT-6 Astra (1.16) are statistically tied on Bug Bench. GPT-6 Astra ranks #3 of 7 and Claude Fable 5.1 #4.
Which is used more, Claude Fable 5.1 or GPT-6 Astra?: GPT-6 Astra, with 19.6% of the AI-written code reviewed by cubic in the week of Sep 14, 2026, against 19.4% for Claude Fable 5.1.