A_M
December 23, 2025, 3:14am
1
Cursor IDE
Updating the project rules to match the new format in the documentation says that the new file should be RULE.md, however Cursor doesn’t detect this as a project rule. Changing the extension back to .mdc allows Cursor to detect the rule.
Currently on Cursor v2.3.1, which I updated to after it wasn’t working on 2.2.x
https://cursor.com/docs/context/rules#project-rules
Create a directory inside .cursor/rules with a rule file name RULE.md to match the format provided in the new documentation (Rules | Cursor Docs )
Go to Cursor → Settings → Cursor Settings → Rules and Commands
See that Project Rules does not pick up the rule
Change file extension to .mdc
See that Project Rules does pick the rule up (May require closing and reopening Cursor Settings)
MacOS
Version: 2.3.2
No - Cursor works, but with this issue
deanrie
December 23, 2025, 5:56am
2
Hey, thanks for the report.
This is a known issue that was fixed recently. Here are a couple things to try:
Reload Window: Command Palette → “Reload Window”
Create a rule via the UI: Settings → Rules → + Add Rule, then check whether new rules use the RULE.md folder format
If you’re still on 2.3.1 or 2.3.2 and it’s not working, the fix may land in the next build. As a workaround, .mdc files work reliably for now.
Related thread with more context: Project Rules: Documented RULE.md folder format not working, only undocumented .mdc format works
Let me know if Reload Window helps, or if the issue still persists after creating a rule via the UI.
This issue is still persistent on the newest releases:
Version: 2.2.43
A_M
December 23, 2025, 10:58pm
4
Hi Dean,
I’m on version 2.3.4 as of this morning and the RULE.md files still aren’t detected after trying Reload Window. When I use the Add Rule button via the UI it’s also still creating the .mdc files.
I converted my rules back to .mdc for now so not a major blocker
Thanks!
Version: 2.3.4
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