Xcode Intelligence Chat Agent Changes Overwrite Entire File

I have this local agent using Qwen 3.6 (the version that is ~17 GB). Last time I tried using this a couple months ago it worked ok.

Now the agent frequently does not know how to edit a file. It takes its proposed changes and completely overwrites the entire source file with the change instead of just modifying the portion of the source code. Sometimes the agent thinks it doesn't have permission to make a change and wants me to copy and paste code.

Is there an Xcode skill provided somewhere that I can use with the Agent so it knows how to work in this environment properly? Currently I have it set up via "Chat" with "Tools Enabled" and "Automatically apply changes" is on.

Xcode Intelligence Chat Agent Changes Overwrite Entire File
 
 
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