The common reason is that Prettier, ESLint, Biome, EditorConfig, or project scripts are triggered when saving, causing the diff just written by the agent to be rearranged by another set of tools. Pause autosave and autoformat before letting the agent make minor changes.
First, confirm who is modifying the file
See if the file changes immediately after it is saved. If the order of indentation, quotation marks, line breaks, and import has changed, it is mostly formatter; If the logic code is also modified, it could be a save hook, lint fix, code generation script, or other extension.
Don't blame Cursor Agent right away. First, check the VS Code/Cursor settings for 'format on save', default formatter, and code actions when saving.
Temporarily turn off automatic actions
When dealing with complex AI modifications, it is recommended to temporarily turn off autosave and save formatting. Let the agent complete the changes before manually running 'format', 'lint --fix', and tests. This makes the diff clearer and easier to locate the problem.
If the team must enable formatting, at least tell the agent: "Don't format manually, output by existing formatter, and finally run the formatting command." ”
Check for multiple formatter conflicts
There are Prettier, ESLint fix, Biome, and built-in formatter in one project at the same time, making it easy to compete with each other. The manifestation is that the file is saved one time at a time, and the content read by the agent is constantly changing.
The solution is to specify a unique default formatter and converge the save action to a set of tools. Team projects are best written in a README or rules file.
The most stable process
Turn off auto-save first, and limit the agent to only modify the target file. After changing it, look at diff; Then manually format; Finally, run the test. If the logic is broken after formatting, it means that there is a conflict between the original changes or the formatter configuration, and then deal with it separately.
AI writing code is not afraid of formatting, but is afraid of being modified by another set of tools while writing. Divide "generate" and "format" into two steps, and Cursor will be much more stable to modify.
