Updated
Claude Fable 5.1 vs GPT-5.5
GPT-5.5 had 60% fewer counted bugs per line than Claude Fable 5.1 (0.47 vs 1.17).
| Claude Fable 5.1 | GPT-5.5 | |
|---|---|---|
| Bug rate | ||
| Relative bug rate | 1.17 | 0.47 |
| Rank | #6 of 9 | #1 of 9 |
| Details | ||
| Provider | Anthropic | OpenAI |
| Released | Sep 1, 2026 | Apr 23, 2026 |
| List price | $10 input / $50 output per 1M tokens | $5 input / $30 output per 1M tokens |
| Share of AI-written code, week of Sep 14 | 19.4% | 0.1% |
1.00 = average · lower is better
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Questions and answers
- Which has fewer bugs, Claude Fable 5.1 or GPT-5.5?
- GPT-5.5 had 60% fewer counted bugs per line than Claude Fable 5.1 (0.47 vs 1.17). GPT-5.5 ranks #1 of 9 and Claude Fable 5.1 #6.
- Which is cheaper, Claude Fable 5.1 or GPT-5.5?
- Claude Fable 5.1 lists at $10 input / $50 output per 1M tokens; GPT-5.5 lists at $5 input / $30 output per 1M tokens. GPT-5.5 has the lower list price.
- Which is used more, Claude Fable 5.1 or GPT-5.5?
- Claude Fable 5.1, with 19.4% of the AI-written code reviewed by cubic in the week of Sep 14, 2026, against 0.1% for GPT-5.5.