Aider

Aider is an AI-assisted pair programming tool that integrates directly with your local codebase through a command-line interface. It connects to large language models and uses your actual repository files as context, allowing the AI to propose and apply code changes grounded in your existing architecture. Aider can create new files, modify existing ones, and refactor code while preserving project structure and style. It works with Git, automatically generating diffs for each change so you can review, edit, and commit with full transparency.

Key capabilities include implementing new features from natural language prompts, fixing bugs based on error messages or failing tests, and assisting with code migrations or framework upgrades. Aider understands multi-file changes, can follow references across the codebase, and supports iterative development where you refine behavior through conversation. It supports multiple programming languages and common frameworks, making it useful for greenfield projects and legacy systems alike.