Project Rules are not respected in Cursor

[aitella]

Describe the Bug

I have project rules set to Always. This is the .mdc file attached to .cursor/files.
When I create new files with Cursor (I mostly use Claude-4-sonnet MAX) or add any new functionality Cursor never respect project rules.
On previous version at least I could explicitly say in a chat “Strictly follow project rules” and some of them (not all) would be respected. Starting with one of the latest version it’s not working at all.

Steps to Reproduce

Open Cursor Settings > Rules
Add a new Project rule > Create a “new rule” (set to “Always”), add a file with rules
Start a new conversation
Ask to create a new component
The component will be created ignoring all the rules

Expected Behavior

Component should be created following every rule in project rules

Operating System

Windows 10/11

Current Cursor Version (Menu → About Cursor → Copy)

Version: 1.2.1 (user setup)
VSCode Version: 1.99.3
Commit: 031e7e0ff1e2eda9c1a0f5df67d44053b059c5d0
Date: 2025-07-03T06:16:02.610Z
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 10.0.22631

Does this stop you from using Cursor

Sometimes - I can sometimes use Cursor

[aitella]

Hey Cursor team and @condor, will this be answered at all? Development become more and more dirty because the rules don’t apply anymore.

Today I explicitly asked agent to read project rules and it didn’t but started changing files with made up rules. I asked it a few times. Only on a forth time after I asked to just read the rules and don’t do anything else - it actually started reading them but didn’t read all of them, just part.
Note: I used claude-sonnet MAX.

[condor]

hi @aitella I just saw your post, it must have gone under in many posts we are handling in the Forum. Sorry about this and thanks for tagging me.

From your post I would say something is confusing the model.

• I suggest keeping rules short and focused. Personally I need only 10 lines of rules to get models to do things the way its needed.
• There is no MDC file mentioned in your screenshot, as the screenshot shows normal handling.

Dan has addressed this quite well in another thread.

Cursor rules - are they still supported by Cursor?

While Cursor always sends your rules to the model and has had some significant work put into ensuring the model respects the rules you give, the models still may choose to ignore them or only partially follow them, especially depending on the contents of the rules. If anyone doesn’t think their rules are being included / followed, we can investigate this with a non-privacy mode request ID, as this will enable me and the team to see what the model was sent and what it’s output was!

[aitella]

Hi @condor , thank you! Yes, our contributing.md is pretty big and was created for both human and AI. I’ll follow your advice and make a smaller version for AI. Hopefully it will help. But it’s still will not be small. The rules are important to keep code base clean. I’ll post my observations.

[condor]

Great, thanks for the update. I’m also using Sonnet 4 with Max.

Happy to chat about what works and how you could adjust things.

Let me know if you want to review more of your process, often a few details can help optimize AI responses.

e.g. with Sonnet 3.5 I had to use more rules so it generates acceptable code. Sonnet 4 actually works better with less as long as your framework and programming language has good best practices, it will use those automatically.