LBPP (Less Basic Python Problems)
DiffusionGemma 26B A4B 81% Only in system cards Models write Python solutions to 161 new problems built to avoid training-set contamination. Hidden tests score pass@1.
The Command A report adds parallel C++, Java, JavaScript, Go and Rust versions.
In the authors’ words
In this paper, we consider contamination by code generation test sets, in particular in their use in modern large language models. We discuss three possible sources of such contamination and show findings supporting each of them: (i) direct data leakage, (ii) indirect data leakage through the use of synthetic data and (iii) overfitting to evaluation sets during model selection. To address this, we release Less Basic Python Problems (LBPP): an uncontaminated new benchmark of 161 prompts with their associated Python solutions. LBPP is released at https://huggingface.co/datasets/CohereForAI/lbpp .
- Level
- University Undergraduates and entry-level professionals
- Scored
- Checked automatically A program checks the result against an answer key, unit tests or the expected final state.
- Answers
- Code A program or patch run against tests.
DiffusionGemma 26B A4B leads with 81%
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.
- 1 DiffusionGemma 26B A4B 81%
- 2
Cohere Command A 51.5%
| # | Model | Score | Setting | Date | Source |
|---|---|---|---|---|---|
| 1 | DiffusionGemma 26B A4B | 81% | Jul 2026 | Model card | |
| 2 | Cohere Command A | 51.5% | Apr 2025 | Model card |
Scores over time
All the scores we have, one dot each, so a model tested at several settings appears more than once.
Labs report it only in system cards
We read the headline results of 479 launch posts from 51 labs, and none of them list this benchmark. Some system cards do, below.
2 system cards report it, from 2 labs
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 |
|---|---|---|---|---|
| 31 Jul 2026 | DiffusionGemma 26B A4B technical report | 81 | LBPP (v2), TD, 68.9 no-think (Table 3) | Capabilities |
| 1 Apr 2025 | Cohere Command A technical report | 51.5 | LBPP (All), six languages (Table 12, Table 26). Python 58.4, Command A Agentic 65.4 | Capabilities |
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