Updated
Claude Fable 5.1
As of Nov 9, 2026, Claude Fable 5.1 ranks #3 of 7 on Bug Bench with a relative bug rate of 0.88 (12% fewer counted bugs than average), statistically tied with GPT-6 Astra.
- Relative bug rate
- 0.88
- Rank of 7
- #3
- Tied with
- GPT-6 Astra
1.00 = average · lower is better
- Provider
- Anthropic
- Released
- Sep 1, 2026
- Price per 1M tokens
- $10 in · $50 out
- First seen
- Week of Aug 31
Nearby in the ranking
| Rank | Model | Rate |
|---|---|---|
| 1 | GPT-6 Luna | 0.31 |
| 2 | GPT-6.1 Sol | 0.74 |
| 3 | Claude Fable 5.1 | 0.88 |
| 4= (statistically tied) | GPT-6 Astra | 0.95 |
| 5 | Claude Sonnet 5.5 | 1.04 |
Is Claude Fable 5.1 getting worse?
Not enough weekly data yet (0 of 6 weeks).
Where it does better or worse
# = rank among models
By coding agent
| Rank | Agent | Rate |
|---|---|---|
| 1 | Claude Code | 0.88 |
How widely Claude Fable 5.1 is used
Share of AI-written code reviewed by cubic
- Latest weekWeek of Nov 2
- 2.8%
- Peak weekWeek of Sep 14
- 19.0%
Compare Claude Fable 5.1
Questions and answers
- Is Claude Fable 5.1 good for coding?
- Claude Fable 5.1 ranks #3 of 7 on Bug Bench, with 12% fewer counted bugs than average (0.88) from Jul 20 to Nov 8, 2026.
- Is Claude Fable 5.1 getting worse?
- Not enough weekly data yet (0 of 6 weeks).
- Which coding agent has the lowest bug rate with Claude Fable 5.1?
- Claude Code, at 0.88.
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