---
language:
- en
license: mit
base_model:
- unsloth/qwen2.5-coder-7b-instruct-bnb-4bit
tags:
- code-review
- grpo
- reinforcement-learning
- lora
- trl
- unsloth
- transformers
- peft
- code
- bugfix
pipeline_tag: text-generation
---

# 🔍 code-review-agent-grpo

A **Qwen2.5-Coder-7B** model fine-tuned with **GRPO (Group Relative Policy Optimization)** to review and fix real-world code bugs across 6 programming languages.

Built for the **Meta × HuggingFace × PyTorch OpenEnv Grand Finale — Bangalore 2026**.

---

## 🏆 Key Result

> **A 7B parameter model, after GRPO training on CodeReviewEnv, outperformed a 70B parameter baseline by 46% on average.**

| Task | Groq llama-3.3-70B (baseline) | Qwen2.5-Coder-7B (GRPO) | Change |
|------|-------------------------------|--------------------------|--------|
| easy | 0.95 | 1.13 | ↑ +0.18 |
| medium | 0.90 | 1.28 | ↑ +0.38 |
| hard | 0.15 | 0.48 | ↑ +0.33 (3x!) |
| api_security | 0.90 | 1.20 | ↑ +0.30 |
| auth_system | 0.00 | 1.13 | ↑ +1.13 (from zero!) |
| **AVERAGE** | **0.58** | **1.04** | **↑ +0.46** |

---

## 🎯 What This Model Does

This model acts as an **AI code reviewer** that can:

1. **Find bugs** — structured comments with line numbers and severity levels
2. **Fix bugs** — suggest correct code patches for each issue found
3. **Issue verdicts** — approve or request changes with clear reasoning
4. **Handle 6 languages** — Python, JavaScript, SQL, React/JSX, Django, Node.js

---

## 🚀 Quick Start

```python
from transformers import pipeline

reviewer = pipeline(
    "text-generation",
    model="lucifer0077/code-review-agent-grpo",
    device_map="auto"
)

code_to_review = """
def process_tasks(queue):
    while queue:
        task = queue.pop(0)  # multiple workers sharing this queue
        handle(task)
"""

prompt = f"""Review this code for bugs. For each bug found, provide:
- Line number
- Severity (critical/major/minor)
- Description
- Suggested fix

Code:
{code_to_review}
"""

output = reviewer(
    [{"role": "user", "content": prompt}],
    max_new_tokens=512,
    return_full_text=False
)[0]

print(output["generated_text"])
```

---

## 🏗️ Training Details

### Environment — CodeReviewEnv

This model was trained inside **CodeReviewEnv**, a custom OpenEnv-compliant RL environment with:

- **13 tasks** across 6 languages
- **Curriculum learning** — automatically promotes agent from easy → medium → hard
- **Anti-reward hacking** — spam detection, duplicate detection, quality checks
- **Dense reward shaping** — rewards at every step, not just episode end

### Reward Function

| Signal | Reward |
|--------|--------|
| ✅ Critical bug found | +0.20 |
| ✅ Major bug found | +0.12 |
| ✅ Minor bug found | +0.05 |
| ❌ False positive | −0.08 |
| ✅ Correct verdict | +0.10 |
| ❌ Wrong verdict | −0.15 |
| ✅ Correct fix (critical) | +0.40 |
| ✅ Correct fix (major) | +0.35 |
| ❌ Wrong fix | −0.10 |
| ⏱️ Step penalty | −0.02/step |

### Hyperparameters

| Parameter | Value |
|-----------|-------|
| Base Model | Qwen2.5-Coder-7B-Instruct |
| GPU | A100 (40GB) |
| Training Steps | 250 |
| Framework | Unsloth + TRL |
| LoRA Rank | 32 |
| Learning Rate | 3e-6 |
| Training Time | 2h 43min |

### Learning Curve

Reward increased from **~0.60 → ~1.15** over 250 training steps, surpassing the Groq llama-3.3-70B baseline (0.58) early in training.

---

## 🌍 Supported Tasks & Languages

| Language | Tasks | Bug Types |
|----------|-------|-----------|
| Python | easy, medium, hard, api_security, auth_system, orm_bugs, data_pipeline | ZeroDivisionError, SQL injection, race conditions, JWT bypass, N+1 queries |
| JavaScript | js_async, node-race | Missing await, callback hell, memory leaks |
| SQL | sql-injection | ORDER BY injection, LIMIT injection |
| React/JSX | react-security | XSS via dangerouslySetInnerHTML, token leaks |
| Django | django-auth | Timing attacks, plaintext comparison |
| Node.js | node-race | Inventory oversell, atomicity bugs |

---

## 🔗 Links

| Resource | Link |
|----------|------|
| 🌐 Live Demo | https://lucifer0077-code-review-env.hf.space |
| 🏋️ Training Space | https://huggingface.co/spaces/lucifer0077/code-review-training |
| 📝 Blog Post | https://huggingface.co/blog/lucifer0077/codereviewenv-grpo-7b-vs-70b |
| 💻 GitHub | https://github.com/Lucifer-cyber007/meta-hackathon-open-env |

---

## 📚 Citation

If you use this model or environment, please cite:

```bibtex
@misc{codereviewenv2026,
  title     = {CodeReviewEnv: A Self-Improving AI Code Review Agent via GRPO},
  author    = {Aditya Sharma},
  year      = {2026},
  publisher = {HuggingFace},
  url       = {https://huggingface.co/lucifer0077/code-review-agent-grpo}
}
```

### Framework Citations

```bibtex
@article{shao2024deepseekmath,
  title  = {DeepSeekMath: Pushing the Limits of Mathematical Reasoning in Open Language Models},
  author = {Zhihong Shao et al.},
  year   = {2024},
  eprint = {arXiv:2402.03300}
}
```

---

*Built at Meta × HuggingFace × PyTorch OpenEnv Grand Finale — April 2026, Bangalore*

*Theme 4: Self-Improving Agent | Theme 3.1: Professional Tasks*