Which has fewer bugs, GPT-5.6 Luna or GPT-5.6 Sol?

GPT-5.6 Sol had 43% fewer counted bugs per line than GPT-5.6 Luna (0.73 vs 1.28). GPT-5.6 Sol ranks #1 of 7 and GPT-5.6 Luna #5.

Which is used more, GPT-5.6 Luna or GPT-5.6 Sol?

GPT-5.6 Sol, with 7.2% of the AI-written code reviewed by cubic in the week of Sep 14, 2026, against 1.7% for GPT-5.6 Luna.

Updated Sep 26, 2026

GPT-5.6 Sol had 43% fewer counted bugs per line than GPT-5.6 Luna (0.73 vs 1.28).

GPT-5.6 Luna and GPT-5.6 Sol compared on relative bug rate, by coding agent, bug type, and language, and on price and usage.
Bug rate
	GPT-5.6 Luna	GPT-5.6 Sol
Relative bug rate	1.28	0.73
Rank	#5 of 7	#1 of 7
By coding agent
Codex	1.32	0.71
Details
Share of AI-written code, week of Sep 14	1.7%	7.2%

1.00 = average · lower is better

Which has fewer bugs, GPT-5.6 Luna or GPT-5.6 Sol?: GPT-5.6 Sol had 43% fewer counted bugs per line than GPT-5.6 Luna (0.73 vs 1.28). GPT-5.6 Sol ranks #1 of 7 and GPT-5.6 Luna #5.
Which is used more, GPT-5.6 Luna or GPT-5.6 Sol?: GPT-5.6 Sol, with 7.2% of the AI-written code reviewed by cubic in the week of Sep 14, 2026, against 1.7% for GPT-5.6 Luna.