Local LLMs For Coding Workflows: Code Generation, Review, and Testing

Which Models Work Best for Local Coding?

How Do You Generate Code With Local LLMs?

# Prompt design for code generation
prompt = """
Implement the following function:

def merge_sorted_arrays(arr1: List[int], arr2: List[int]) -> List[int]:
    \"\""
    Merge two sorted arrays into a single sorted array.
    Args:
        arr1: First sorted array
        arr2: Second sorted array
    Returns:
        Merged sorted array
    \"\""
    # Implementation:
"""

# Model outputs implementation
# Expected: Two-pointer merge algorithm

How Do You Review Code With Local LLMs?

• Prompt: "Review this code for bugs, security issues, and performance." + code snippet.
• Model identifies: unused variables, potential None errors, inefficient loops.
• Limitations: Cannot understand complex domain logic or architectural patterns.

How Do You Generate Tests?

# Prompt for test generation
prompt = """
Write comprehensive unit tests for this function:

[function code]

Generate tests covering:
- Normal cases
- Edge cases
- Error cases

Use pytest format:
"""

# Model generates test_* functions with assertions

How Do You Set Up IDE Integration?

• VS Code + Continue.dev: Install extension, point to local Ollama server (http://localhost:11434).
• Cursor editor: Built-in support for Ollama. No setup required.
• Inline completions: Ctrl+Shift+\\ (VS Code) or Cmd+Shift+\\ (Mac) triggers local LLM suggestion.

What Are Common Mistakes?

• Trusting generated code without review. Generated code can have bugs. Always review.
• Using models too small. Qwen2.5-Coder 7B is minimum for practical coding. 3B models produce poor code.
• Not providing context. Code quality depends on prompt context. Provide function signature, types, docstrings.
• Expecting it to understand architecture. Local models understand individual functions, not system design.
• Not using a coding-specific model. General-purpose models (Llama 3.1 8B, Mistral 7B) score 15–25% lower on HumanEval than coding models (Qwen2.5-Coder 7B: 72% vs Llama 3.1 8B: 55%). Always use a model trained specifically for code. In Ollama: `ollama pull qwen2.5-coder:7b` — not `ollama pull llama3.1:8b` for coding tasks.

Frequently Asked Questions

Related Reading

• Best AI Coding Assistant for Local LLM — Choose between Cursor, Continue.dev, Cody and other IDE tools for your coding model.
• Local LLMs With VS Code and Cursor — Detailed setup guide for both IDEs
• Prompt Engineering Guide — Master prompting techniques to improve code generation
• Best Local LLMs for Coding — Detailed benchmarks and model comparisons
• Local LLM Hardware Guide 2026 — GPU requirements and cost analysis
• Local RAG for Code Search — Search existing code with semantic understanding
• Private Local AI For Business — Enterprise deployment and compliance

Sources

• HumanEval Benchmark — Official code generation benchmark from OpenAI
• Qwen2.5-Coder Model Card — Qwen2.5-Coder model specs and evaluation results
• Continue.dev IDE Extension — Open-source IDE support for local and cloud LLMs
• Local LLMs excel at code generation, but code quality depends on prompt quality. Learn coding-specific prompt techniques: write better code with AI covers testing, review, and iteration.