Chat Checkpoints don't revert code properly

Support Bug Reports
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1

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

When I revert changes an agent has made via the undo button, they don’t actually undo the changes the agent made to those files. It’s also strange because I don’t see the normal approve/decline UI for each of the changes the agent has made to the file. Making me think that something related to the state of the file has been broken. This is reproduced in 2.5 and 2.6 and 2.7.

Steps to Reproduce

Ask agent to edit a file (can be big or small), a bigger edit shows the headache it is when reverting because there’s no easy way of cleaning up. But ask it to edit a file, then wait for it to complete, then click the undo btn. It should properly undo the chat message, but not the actual code in the file.

Expected Behavior

The expected behavior should be to revert the code edits to the previous state.

Operating System

Windows 10/11

Version Information

Cursor IDE, Version 2.5.25

For AI issues: which model did you use?

Opus 4.6 Max, but isn’t an AI issue it seems more state related.

For AI issues: add Request ID with privacy disabled

8610ffdd-4760-4fd6-918f-43631bd21df9

Additional Information

I emailed cursor support with video, video’s too long to upload to this apparently. So here’s a onedrive link.

https://clinicknet-my.sharepoint.com/:v:/g/personal/ethan_clinick_net/IQDPXKc2oQT5SrDW58juugC9AZ-I4vCM8tNd8d1dLHyTFNE

Does this stop you from using Cursor

Yes - Cursor is unusable

3

Hey, thanks for the report. This is a known bug with diff rendering. When the agent makes edits and the diff doesn’t show correctly, the Keep and Undo buttons don’t appear, and reverting to a checkpoint breaks. The chat looks reverted, but the files stay modified.

More details and the main thread: Keep / Undo buttons missing and “Discard to checkpoint” not reverting changes

Workaround: make a git commit before big agent sessions. If checkpoint revert doesn’t work, you can always roll back with git checkout -- . or git stash.