Updated

Claude Fable 5 vs Claude Sonnet 5

Claude Fable 5 had 67% fewer counted bugs per line than Claude Sonnet 5 (0.70 vs 2.10).

Claude Fable 5 and Claude Sonnet 5 compared on relative bug rate, by coding agent, bug type, and language, and on price and usage.
Claude Fable 5Claude Sonnet 5
Bug rate
Relative bug rate0.702.10
Rank#2 of 9#9 of 9
By coding agent
Claude Code0.722.12
Details
ProviderAnthropicAnthropic
ReleasedJun 9, 2026Jun 30, 2026
List price$10 input / $50 output per 1M tokens$2 input / $10 output per 1M tokens
Share of AI-written code, week of Sep 140.9%4.0%

1.00 = average · lower is better

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Questions and answers

Which has fewer bugs, Claude Fable 5 or Claude Sonnet 5?
Claude Fable 5 had 67% fewer counted bugs per line than Claude Sonnet 5 (0.70 vs 2.10). Claude Fable 5 ranks #2 of 9 and Claude Sonnet 5 #9.
Which is cheaper, Claude Fable 5 or Claude Sonnet 5?
Claude Fable 5 lists at $10 input / $50 output per 1M tokens; Claude Sonnet 5 lists at $2 input / $10 output per 1M tokens. Claude Sonnet 5 has the lower list price.
Which is used more, Claude Fable 5 or Claude Sonnet 5?
Claude Sonnet 5, with 4.0% of the AI-written code reviewed by cubic in the week of Sep 14, 2026, against 0.9% for Claude Fable 5.