Monorepo-Bench
Agents replicate pull-request style contributions in a large internal OpenAI repository. Graded by hidden unit tests as pass@1.
In-house OpenAI AI self-improvement evaluation. The tasks are not public.
- Made by
- OpenAI
- Released
- February 2026
- Kind
- Labs' internal R&D tests
- Level
- Research frontier
- Scored
- Checked automatically
- Answers
- Agent task
- Tasks
- Kept private
- Strongest model tested
- GPT-6 Astra #3 on the capability index
- Last in a system card
- September 2026
- Last model added
- September 2026
GPT-6 Astra leads with 76% among models released by September 2026
Best score per model as labs report them in their own cards. Labs pick their own settings, so these compare less cleanly than independent runs.
The newest model with a score here came out in September 2026, and nobody has reported a newer one. Among the 20 highest-ranked models on the capability index, these have no score yet:
- Claude Fable 5.2
-
Gemini 4 Carbon - Claude Opus 5.5
- GPT-6.1 Sol
- and 14 more
- 1 GPT-6 Astra 76%
- 2 GPT-5.5 60%
- 3 GPT-5.4 59.3%
- 4 GPT-5.3 Codex 56%
- 5 GPT-5.4 Mini 54%
Source: Labs’ model cards
| # | Model | Score | Setting | Date | Source |
|---|---|---|---|---|---|
| 1 | GPT-6 Astra | 76% | Sep 2026 | Lab model card | |
| 2 | GPT-5.5 | 60% | Apr 2026 | Lab model card | |
| 3 | GPT-5.4 | 59.3% | Mar 2026 | Lab model card | |
| 4 | GPT-5.3 Codex | 56% | Feb 2026 | Lab model card | |
| 5 | GPT-5.4 Mini | 54% | Mar 2026 | Lab model card |
4 models have held number one in labs’ own numbers since its release in February 2026
Lab claims count from the day the card came out, independent runs from the model’s release.
Source: Labs’ model cards
Scores over time
All the scores we have, one dot each, so a model tested at several settings appears more than once.
Source: Labs’ model cards
Labs report it only in system cards
We read the headline results of 522 launch posts from 52 labs, and none of them list this benchmark. Some system cards do, below.
5 system cards report it, from 1 lab
Besides launch posts, we read the system cards, model cards and technical reports labs publish with a release. They report far more, including safety and frontier-risk tests.
| Date | Document | Score | As the document writes it | Section |
|---|---|---|---|---|
| Sep 3, 2026 | GPT-6 Astra system card | 76 | OAI-repoBench (Monorepo-Bench) native unit-test pass rate, baseline condition, 50 tasks, medium reasoning effort, printed chart label (Figure 37) | Monitorability |
| Apr 23, 2026 | GPT-5.5 system card | 60 | Monorepo-Bench, pass@1, printed chart label (Figure 18, 9.1.3.1) | AI R&D risk |
| Mar 17, 2026 | GPT-5.4 Mini system card | 54 | Monorepo-Bench, pass@1 (Table 20) | AI R&D risk |
| Mar 5, 2026 | GPT-5.4 system card | 59.3 | Monorepo-Bench, pass@1, printed chart label (Figure 15, 5.1.3.1) | AI R&D risk |
| Feb 5, 2026 | GPT-5.3 Codex system card | 56 | Monorepo-Bench, pass@1, printed chart label (Figure 8, 5.1.3.1) | AI R&D risk |
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