Updated
Claude Fable 5.1 vs GPT-6 Astra
Claude Fable 5.1 (0.88) and GPT-6 Astra (0.95) are statistically tied on Bug Bench.
| Claude Fable 5.1 | GPT-6 Astra | |
|---|---|---|
| Bug rate | ||
| Relative bug rate(statistically tied) | 0.88 | 0.95 |
| Rank | #3 of 7 | #4 of 7 |
| By language | ||
| TypeScript(statistically tied) | 1.05 | 1.08 |
| JavaScript | 1.09 | 1.63 |
| Python | 0.83 | 1.18 |
| Go | 1.27 | 0.88 |
| Rust | 1.34 | 0.36 |
| Ruby | 0.41 | 1.25 |
| SQL(statistically tied) | 1.12 | 0.94 |
| Shell(statistically tied) | 0.69 | 0.67 |
| Vue(statistically tied) | 0.40 | 0.69 |
| Terraform(statistically tied) | 0.82 | 0.44 |
| Details | ||
| Provider | Anthropic | OpenAI |
| Released | Sep 1, 2026 | Sep 4, 2026 |
| List price | $10 input / $50 output per 1M tokens | $10 input / $50 output per 1M tokens |
| Share of AI-written code, week of Nov 2 | 2.8% | 4.5% |
1.00 = average · lower is better · = statistically tied
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Questions and answers
- Which has fewer bugs, Claude Fable 5.1 or GPT-6 Astra?
- Claude Fable 5.1 (0.88) and GPT-6 Astra (0.95) are statistically tied on Bug Bench. Claude Fable 5.1 ranks #3 of 7 and GPT-6 Astra #4.
- Which is cheaper, Claude Fable 5.1 or GPT-6 Astra?
- Both list at $10 input / $50 output per 1M tokens.
- Does it depend on the programming language?
- In TypeScript, they were statistically tied (1.05 and 1.08); in JavaScript, Claude Fable 5.1 had the lower rate (1.09 vs 1.63); in Python, Claude Fable 5.1 had the lower rate (0.83 vs 1.18); in Go, GPT-6 Astra had the lower rate (0.88 vs 1.27); in Rust, GPT-6 Astra had the lower rate (0.36 vs 1.34); in Ruby, Claude Fable 5.1 had the lower rate (0.41 vs 1.25); in SQL, they were statistically tied (1.12 and 0.94); in shell scripts, they were statistically tied (0.69 and 0.67); in Vue, they were statistically tied (0.40 and 0.69); in Terraform, they were statistically tied (0.82 and 0.44).
- Which is used more, Claude Fable 5.1 or GPT-6 Astra?
- GPT-6 Astra, with 4.5% of the AI-written code reviewed by cubic in the week of Nov 2, 2026, against 2.8% for Claude Fable 5.1.