Which Claude model is best for coding?

Claude Fable 5.1 had the lowest relative bug rate of the 4 ranked Anthropic models from Jun 22 to Oct 11, 2026 (1.09, 9% more counted bugs than the all-model average), statistically tied with Claude Sonnet 5.5.

Which Claude model writes the most bugs?

As of Oct 13, 2026, Claude Opus 5.5 had the highest relative bug rate among Anthropic models (1.50, 50% more counted bugs than the all-model average).

Updated Oct 13, 2026

Anthropic models for coding, ranked

As of Oct 13, 2026, Claude Fable 5.1 had the lowest relative bug rate of the 4 ranked Anthropic models (1.09, 9% more counted bugs than the all-model average), statistically tied with Claude Sonnet 5.5.

Ranking window Jun 22 to Oct 11, 2026

Anthropic models ranked by relative bug rate, where 1.00 is the all-model average. Lower values are better. Models without a rate are listed with their status.
Rank	Model	Rate
1= (statistically tied)	Claude Fable 5.1	1.09
2= (statistically tied)	Claude Sonnet 5.5	1.27
3= (statistically tied)	Claude Opus 5	1.33
4	Claude Opus 5.5	1.50
–	Claude Haiku 5.5	Not ranked yet
–	Claude Fable 5	No longer ranked
–	Claude Opus 4.8	No longer ranked

1.00 = all-model average · lower is better · = statistically tied

Full Bug Bench ranking →Methodology →

Anthropic vs OpenAI

OpenAI's top-ranked model is GPT-5.6 Sol. GPT-5.6 Sol had 40% fewer counted bugs per line than Claude Fable 5.1 (0.65 vs 1.09). Claude Fable 5.1 vs GPT-5.6 Sol

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Questions and answers

Which Claude model is best for coding?: Claude Fable 5.1 had the lowest relative bug rate of the 4 ranked Anthropic models from Jun 22 to Oct 11, 2026 (1.09, 9% more counted bugs than the all-model average), statistically tied with Claude Sonnet 5.5.
Which Claude model writes the most bugs?: As of Oct 13, 2026, Claude Opus 5.5 had the highest relative bug rate among Anthropic models (1.50, 50% more counted bugs than the all-model average).