Describe the Bug
When attempting to edit .mdc files within the .cursor/rules/ directory, the changes are not applied as expected. It cannot apply the rule on “rule creation” correctly, eventhough it read and to acknowledged the template which it needs to use. The editing tool consistently fails to correctly modify the file content, leading to malformed files, duplicated content, or no changes at all. This issue prevents the creation and modification of custom rules for the assistant.
This is true for all auto models, for claude 4 sonnet and for gemini 2.5.
Gemini was the only model that managed to explain that it wants to use the template, but editing the mdc rule file according to it doesn’t work.
Steps to Reproduce
1 create a rule about how to create compliant rules (‘description:’ and the other stuff at the top)
2 AI acknowledges the provided template but fails to apply it correctly (‘description:’ and the other stuff missing or at the bottom).
3 AI acknowledges its failure to put the ■■■■ globs and description etc at the top of the document, but can’t help it even when retrying 3 times with user input help.
4 AI says sorry.
Expected Behavior
put the ■■■■ globs at the start of the document
Operating System
Windows 10/11
Current Cursor Version (Menu → About Cursor → Copy)
Version: 1.2.4 (user setup)
VSCode Version: 1.99.3
Commit: a8e95743c5268be73767c46944a71f4465d05c90
Date: 2025-07-10T17:09:01.383Z
Electron: 34.5.1
Chromium: 132.0.6834.210
Node.js: 20.19.0
V8: 13.2.152.41-electron.0
OS: Windows_NT x64 10.0.26100
Additional Information
AI:
I have the rule files. I’ll check terminal-command-separator.mdc and user-discovered-a-problem.mdc for template compliance, starting with the former. rules.mdc is the template, so I’ll begin there.
The previous edit failed. I will try again to add the required header to the terminal-command-separator.mdc file to make it compliant with the rule template
I am still having trouble creating this file correctly. It seems to be duplicating content. I will try to create the file from scratch one more time.
The edits are not being applied as expected. It seems there is an issue with the editing tool.
All of these attempts have failed to apply the edits as intended. Given the repeated failures, I am unable to fulfill your request at this time. It appears there is a problem with the tool that applies file edits. I recommend you contact support or try the operation again later.
Does this stop you from using Cursor
No - Cursor works, but with this issue