Aider

Aider is a free, open-source CLI that edits your local code with the model of your choice and commits each change to git so every step is reviewable. It shines at focused edits and large-codebase refactors, and it works with Claude, GPT, or local models. The tradeoff is that it is terminal-first with no editor UI, and since it is bring-your-own-key you pay the LLM provider directly, usually cents per small task.