AI Code Generation Complete Guide 2026: From Prompt to Production

# Prompt
"""
Write a Python function that:
1. Takes a list of numbers
2. Returns the median value
3. Handles empty lists
"""

# Generated code
def find_median(numbers: list) -> float:
    """Find the median of a list of numbers."""
    if not numbers:
        raise ValueError("Cannot find median of empty list")
    
    sorted_numbers = sorted(numbers)
    n = len(sorted_numbers)
    
    if n % 2 == 0:
        return (sorted_numbers[n//2 - 1] + sorted_numbers[n//2]) / 2
    else:
        return sorted_numbers[n//2]

# Generate a data class with validation
"""
Create a Python class for User with:
- name, email, age fields
- Email validation
- Age must be positive
- __str__ method
"""

class User:
    def __init__(self, name: str, email: str, age: int):
        self.name = name
        self.email = email
        self.age = age
        self._validate()
    
    def _validate(self):
        if not self.name:
            raise ValueError("Name is required")
        
        if "@" not in self.email:
            raise ValueError("Invalid email")
        
        if self.age < 0:
            raise ValueError("Age must be positive")
    
    def __str__(self):
        return f"User(name={self.name}, email={self.email}, age={self.age})"

# Generate unit tests for a function
"""
Write pytest tests for a function that calculates factorial
"""

import pytest
from math import factorial

def test_factorial_zero():
    assert factorial(0) == 1

def test_factorial_positive():
    assert factorial(1) == 1
    assert factorial(5) == 120

def test_factorial_negative():
    with pytest.raises(ValueError):
        factorial(-1)

# Bad
# write code

# Good
"""
Write a Python function that:
- Takes a list of dictionaries with 'name' and 'score' keys
- Returns the highest scorer
- Returns None if list is empty
- Uses type hints
"""

# Include imports, class definitions, etc.
"""
Given this function signature:
def calculate_statistics(data: list[float]) -> dict:

Write the implementation that returns:
- mean, median, mode, std_dev
- Handle empty list
- Use typing
"""

# Use AI as a pair programmer
class AIPairProgrammer:
    def __init__(self, client):
        self.client = client
    
    def review_code(self, code: str) -> str:
        prompt = f"""Review this code for bugs, security issues, 
        and performance improvements:
        
        ```{code}```
        
        Provide specific suggestions."""
        return self.client.generate(prompt)
    
    def refactor(self, code: str, goal: str) -> str:
        prompt = f"""Refactor this code to {goal}:
        
        ```{code}```
        
        Explain the changes made."""
        return self.client.generate(prompt)