Updated

Claude Sonnet 5.5 vs GPT-6 Luna

GPT-6 Luna had 58% fewer counted bugs per line than Claude Sonnet 5.5 (0.45 vs 1.07).

Claude Sonnet 5.5 and GPT-6 Luna compared on relative bug rate, by language, and on price and usage.
Claude Sonnet 5.5GPT-6 Luna
Bug rate
Relative bug rate1.070.45
Rank#4 of 7#1 of 7
By language
TypeScript(statistically tied)0.760.73
Details
ProviderAnthropicOpenAI
ReleasedSep 28, 2026Sep 22, 2026
List price$2 input / $10 output per 1M tokens$0.10 input / $0.50 output per 1M tokens
Share of AI-written code, week of Oct 124.8%1.4%

1.00 = average · lower is better · = statistically tied

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Questions and answers

Which has fewer bugs, Claude Sonnet 5.5 or GPT-6 Luna?
GPT-6 Luna had 58% fewer counted bugs per line than Claude Sonnet 5.5 (0.45 vs 1.07). GPT-6 Luna ranks #1 of 7 and Claude Sonnet 5.5 #4.
Which is cheaper, Claude Sonnet 5.5 or GPT-6 Luna?
Claude Sonnet 5.5 lists at $2 input / $10 output per 1M tokens; GPT-6 Luna lists at $0.10 input / $0.50 output per 1M tokens. GPT-6 Luna has the lower list price.
Does it depend on the programming language?
In TypeScript, they were statistically tied (0.76 and 0.73).
Which is used more, Claude Sonnet 5.5 or GPT-6 Luna?
Claude Sonnet 5.5, with 4.8% of the AI-written code reviewed by cubic in the week of Oct 12, 2026, against 1.4% for GPT-6 Luna.