aider/aider/website/docs/troubleshooting/edit-errors.md

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Troubleshooting	10

File editing problems

Sometimes the LLM will reply with some code changes that don't get applied to your local files. In these cases, aider might say something like "Failed to apply edit to filename" or other error messages.

This usually happens because the LLM is disobeying the system prompts and trying to make edits in a format that aider doesn't expect. Aider makes every effort to get the LLM to conform, and works hard to deal with LLMM edits that are "almost" correctly formatted.

But sometimes the LLM just won't cooperate. In these cases, here are some things you might try.

Use a capable model

If possible try using GPT-4o, Claude 3.5 Sonnet or Claude 3 Opus, as they are the strongest and most capable models.

Weaker models are more prone to disobeying the system prompt instructions. Most local models are just barely capable of working with aider, so editing errors are probably unavoidable.

Reduce distractions

Many LLM now have very large context windows, but filling them with irrelevant code or conversation can confuse the model.

• Don't add too many files to the chat, just add the files you think need to be edited. Aider also sends the LLM a map of your entire git repo, so other relevant code will be included automatically.
• Use /drop to remove files from the chat session which aren't needed for the task at hand. This will reduce distractions and may help GPT produce properly formatted edits.
• Use /clear to remove the conversation history, again to help GPT focus.

More help

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