Updated
Claude Fable 5 vs Claude Fable 5.1
Claude Fable 5 had 40% fewer counted bugs per line than Claude Fable 5.1 (0.70 vs 1.17).
| Claude Fable 5 | Claude Fable 5.1 | |
|---|---|---|
| Bug rate | ||
| Relative bug rate | 0.70 | 1.17 |
| Rank | #2 of 9 | #6 of 9 |
| By coding agent | ||
| Claude Code | 0.72 | 1.17 |
| Details | ||
| Provider | Anthropic | Anthropic |
| Released | Jun 9, 2026 | Sep 1, 2026 |
| List price | $10 input / $50 output per 1M tokens | $10 input / $50 output per 1M tokens |
| Share of AI-written code, week of Sep 14 | 0.9% | 19.4% |
1.00 = average · lower is better
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Questions and answers
- Which has fewer bugs, Claude Fable 5 or Claude Fable 5.1?
- Claude Fable 5 had 40% fewer counted bugs per line than Claude Fable 5.1 (0.70 vs 1.17). Claude Fable 5 ranks #2 of 9 and Claude Fable 5.1 #6.
- Which is cheaper, Claude Fable 5 or Claude Fable 5.1?
- Both list at $10 input / $50 output per 1M tokens.
- Which is used more, Claude Fable 5 or Claude Fable 5.1?
- Claude Fable 5.1, with 19.4% of the AI-written code reviewed by cubic in the week of Sep 14, 2026, against 0.9% for Claude Fable 5.