Updated
GPT-5.6 Luna
As of Sep 26, 2026, GPT-5.6 Luna ranks #5 of 7 on Bug Bench with a relative bug rate of 1.28 (28% more counted bugs than average), statistically tied with GPT-6 Astra and Claude Fable 5.1.
- Relative bug rate
- 1.28
- Rank of 7
- #5
- Tied with
- GPT-6 Astra and Claude Fable 5.1
1.00 = average · lower is better
- First seen
- Week of Jul 6
Nearby in the ranking
| Rank | Model | Rate |
|---|---|---|
| 3= (statistically tied) | GPT-6 Astra | 1.16 |
| 4= (statistically tied) | Claude Fable 5.1 | 1.17 |
| 5 | GPT-5.6 Luna | 1.28 |
| 6 | Claude Opus 5 | 1.58 |
| 7 | Claude Sonnet 5 | 2.10 |
Is GPT-5.6 Luna 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 |
|---|---|---|
| 2 | Codex | 1.32 |
How widely GPT-5.6 Luna is used
Share of AI-written code reviewed by cubic
- Latest weekWeek of Sep 14
- 1.7%
- This week so farSince Sep 21
- 0.9%
- Peak weekWeek of Aug 24
- 2.8%
Compare GPT-5.6 Luna
Questions and answers
- Is GPT-5.6 Luna good for coding?
- GPT-5.6 Luna ranks #5 of 7 on Bug Bench, with 28% more counted bugs than average (1.28) from Jun 1 to Sep 20, 2026.
- Is GPT-5.6 Luna getting worse?
- Not enough weekly data yet (0 of 6 weeks).
- Which coding agent has the lowest bug rate with GPT-5.6 Luna?
- Codex, at 1.32.
Embed GPT-5.6 Luna's Bug Bench badge
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