Aider

Warnings

• gotcha Aider frequently updates its default model aliases (e.g., `gemini`, `flash`, `sonnet`, `opus`) and provider priorities across releases. This can lead to users unintentionally using different models or providers than expected if they don't explicitly specify their desired model with the `--model` flag.
  Fix: Always explicitly specify your desired model using `aider --model your/model-name ...` to ensure consistent behavior, or regularly check release notes for alias changes.
• gotcha Aider requires API keys for LLM providers (e.g., OpenAI, Anthropic, Google Gemini, OpenRouter) to function. These keys must be configured correctly, typically as environment variables (e.g., `OPENAI_API_KEY`, `ANTHROPIC_API_KEY`, `GEMINI_API_KEY`, `OPENROUTER_API_KEY`). Misconfiguration or missing keys will prevent Aider from communicating with LLMs.
  Fix: Ensure the correct API key environment variable for your chosen provider is set before running Aider. Refer to the official Aider documentation for specific provider setup instructions (aider.chat/docs/llms.html).
• breaking Aider has strict Python version requirements, currently `Python >=3.10, <3.13`. Installing or running Aider with unsupported Python versions (e.g., Python 3.9 or Python 3.13+) will lead to installation failures, dependency conflicts, or runtime errors as indicated by pip's `Requires-Python` metadata.
  Fix: Use a Python environment manager (e.g., `pyenv`, `conda`, `venv`) to ensure you are running Aider with a compatible Python version (e.g., Python 3.10, 3.11, or 3.12). For example, `python3.12 -m pip install aider-chat`.

Install

• pip install aider-chat Install Aider

Quickstart

This quickstart demonstrates how to set up a dummy project with a `main.py` file and a git repository, then launch Aider via the command line. Aider operates interactively in your terminal, acting as an AI pair programmer. You'll need to set an API key for your chosen LLM provider (e.g., OpenAI, Anthropic, Gemini) as an environment variable or pass it via CLI arguments. The example uses a `subprocess.run` call to execute Aider, allowing for direct terminal interaction.

# 1. Set your API key (e.g., OpenAI, Anthropic, Gemini, OpenRouter)
# For OpenAI, set OPENAI_API_KEY. For other providers, check Aider docs.
# export OPENAI_API_KEY="sk-..." (Linux/macOS)
# $env:OPENAI_API_KEY="sk-..." (PowerShell)

import os
import subprocess
import shutil

# Using a dummy key for demonstration; replace with your actual key
openai_api_key = os.environ.get('OPENAI_API_KEY', 'sk-xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx')

if not openai_api_key.startswith('sk-'):
    print("WARNING: OPENAI_API_KEY not set or invalid. Aider will likely fail without a valid key.")

# Create a dummy project directory and a file to edit
project_dir = "aider_quickstart_project"
if os.path.exists(project_dir):
    shutil.rmtree(project_dir) # Clean up previous run
os.makedirs(project_dir)

os.chdir(project_dir)

with open("main.py", "w") as f:
    f.write("def hello_world():\n    print('Hello')\n")

# Initialize a git repo (Aider works best with git)
subprocess.run(["git", "init", "-b", "main"], check=True, capture_output=True)
subprocess.run(["git", "add", "main.py"], check=True, capture_output=True)
subprocess.run(["git", "commit", "-m", "Initial commit"], check=True, capture_output=True)

print(f"\nCreated '{project_dir}/main.py' and initialized git. Now launching Aider...\n")
print("To interact, type your requests into the terminal. E.g., 'Add 'world!' to the print statement.'")
print("Type '/help' for Aider commands, or '/exit' to quit.\n")

# Run Aider. The user will interact with it in the terminal.
# Use a model alias like 'gpt-4o' if OPENAI_API_KEY is set.
# Set environment variables for the subprocess call.
# Note: This will block until Aider exits.
result = subprocess.run(
    ["aider", "--model", "gpt-4o", "main.py"],
    env={**os.environ, 'OPENAI_API_KEY': openai_api_key},
    check=False # Aider might exit with non-zero if user cancels, etc.
)

print(f"\nAider process exited with code {result.returncode}.")
print(f"Check '{os.path.join(project_dir, 'main.py')}' for changes.")

# Clean up (optional)
os.chdir("..")
shutil.rmtree(project_dir)
print(f"Cleaned up '{project_dir}'.")