Problem
I’ve tried to make Cursor to write it’s own rules. In theory it should’ve worked like:
- You solve a task in agent mode
- Ask him to update related rules to keep it updated
It just does not work. Cursor seems like does not know what “rules” is. Ok, fine, understandable. Next try.
I just write prompt like “Update @global.mdc according to what we just did”. Where global.mdc is .cursor/rules/global.mdc
Cursor sees the file, can read it and even tries to apply to the file, but in fact it silently fails. In the chat it looks like an usual file apply, but it hadn’t been applied to the actual file.
Even if I click “Apply” it doesn’t work. No errors, nothing, like it worked, but it didn’t.
Ok, i can copy the new content to the file, but would it be much better it Cursor could apply to it’s rules. Even more, seems like it cannot apply to *.mdc at all.
Example
I created an empty project with only global.mdc file (in the root, not in .cursor folder). And ask the agent to add info. It did, but it didn’t.
As you can see, there is no “new line” in the file. I had clicked the “apply” too.
Checking in the terminal:
Sys info:
Version: 0.46.11
VSCode Version: 1.96.2
Commit: ae378be9dc2f5f1a6a1a220c6e25f9f03c8d4e10
Date: 2025-03-07T06:43:50.208Z
Electron: 32.2.6
Chromium: 128.0.6613.186
Node.js: 20.18.1
V8: 12.8.374.38-electron.0
OS: Darwin arm64 24.3.0