Run aider with the source code files you want to edit. These files will be “added to the chat session”, so that aider can see their contents and edit them for you. They can be existing files or the name of files you want aider to create for you.

aider <file1> <file2> ...

At the aider > prompt, ask for code changes and aider will edit those files to accomplish your request.

$ aider

Aider v0.37.1-dev
Models: gpt-4o with diff edit format, weak model gpt-3.5-turbo
Git repo: .git with 258 files
Repo-map: using 1024 tokens
Use /help to see in-chat commands, run with --help to see cmd line args
>`Make a program that asks for a number and prints its factorial


Adding files

Just add the files that the aider will need to edit. If you add too many files, the LLM can get overwhelmed and confused (and it costs more tokens). Aider will automatically pull in content from related files so that it can understand the rest of your code base.

You can also run aider without naming any files and use the in-chat /add command to add files.

Or you can skip adding files completely, and aider will try to figure out which files need to be edited based on your requests.


Aider uses GPT-4o by default, but you can connect to many different LLMs. Claude 3 Opus is another model which works very well with aider, which you can use by running aider --opus.

You can run aider --model XXX to launch aider with a specific model. Or, during your chat you can switch models with the in-chat /model command.

Making changes

Ask aider to make changes to your code. It will show you some diffs of the changes it is making to complete you request. Aider will git commit all of its changes, so they are easy to track and undo.

You can always use the /undo command to undo changes you don’t like.

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