Cursor Rules not being followed

Bug Reports
1

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

I have defined a set of instructions in my rules.md file inside .cursor/rules folder. One of the items i had mentioned is to never mock data. There are few other rules, but cursor seems to add mock data when the real server/integration is not working.

Isnt every chat session in the cursor IDE follow the rules defined in .cursor/rules folder

Steps to Reproduce

Create a rule.md file inside .cursor/rules folder. Set an instruction stating that no mock data be used/generated

Expected Behavior

No mock data being created

Operating System

MacOS

Current Cursor Version (Menu → About Cursor → Copy)

Version: 1.7.54 (Universal)
VSCode Version: 1.99.3
Commit: 5c17eb2968a37f66bc6662f48d6356a100b67be0
Date: 2025-10-21T19:07:38.476Z (2 days ago)
Electron: 34.5.8
Chromium: 132.0.6834.210
Node.js: 20.19.1
V8: 13.2.152.41-electron.0
OS: Darwin arm64 24.1.0

Does this stop you from using Cursor

No - Cursor works, but with this issue

2

Hey, thanks for the report. Lately, we’ve seen several reports that rules aren’t being applied correctly.

To help narrow it down, please share:

  • Which model you’re using in chat (Claude Sonnet, GPT, Cheetah, etc.)?
  • Where this happens: Chat, Agent, custom mode, or Background Agent?

What to do:

  • Use the .mdc extension: in .cursor/rules/rules.mdc add conditions with alwaysApply: true or autoAttach: true. Rules | Cursor Docs
  • Check whether the rules show as active in the Agent sidebar when you’re in a chat session

Temporary workarounds:

  • Reference your rules with @Rules in each chat
  • Add a “no mock data” instruction directly to your request
  • Set “Always Apply” in the rule if it’s not already

There are known issues with rules not loading in Background Agent and some other contexts, so this info will help determine if it’s the same issue or something different.

3

Thanks @deanrie

  1. I have set it to Auto which i think was using Claude Sonnet.
  2. This happens in the Chat
4

This topic was automatically closed 22 days after the last reply. New replies are no longer allowed.