Why My Cursor Project Rules Stopped Working in 1.0.0 and How I Fixed It

After updating my Cursor IDE to version 1.0.0, I hit a major roadblock: my project rules completely stopped applying. As a developer who relies on these rules for team consistency and AI guidance, this bug made coding sessions chaotic and inefficient. I spent days digging into solutions, and here’s what I learned.

The Core Problem

In the new version, project rules set to “Always” weren’t being included in conversations, even when I manually added them via the @ symbol. For instance, a debugging rule designed to list all applied rules at the start of chats wasn’t showing up. This was most noticeable in Agent mode, where critical instructions—like using specific commands for running tests—were ignored, leading to wasted credits and confusion.

How I Diagnosed the Issue

I tested various scenarios to pinpoint the problem. First, I verified that rules were correctly set in Cursor settings but saw no evidence they were being loaded. Then, I reproduced it by adding a simple rule and starting a new conversation—consistently, nothing appeared. What surprised me was how flaky it felt; sometimes rules worked after a restart, but not always, and it varied across different codebases.

Solutions That Worked for Me

Through experimentation, I found several reliable fixes. Here’s a step-by-step breakdown of what resolved the issue:

• Restart Cursor or Your Computer: Often, a full restart of the app or system cleared cached errors. For example, shutting down my laptop and rebooting brought rules back to life immediately.
• Delete the .cursor Folder: Navigate to your project directory, delete the hidden .cursor folder, restart Cursor, and re-add your rules. This reset the configuration and fixed cases where rules weren’t loading at all.
• Ensure You’re in Agent Mode: Project rules only apply in Agent mode. Double-check your mode settings before expecting rules to work—Ask and Manual modes ignore them entirely.
• Add a Blank Rule as a Trigger: In settings, create a new rule with dummy content (e.g., name it “asdf”). This often forces Cursor to recognize and load existing rules again.
• Adjust Model Settings: Switching the AI model in Agent mode (e.g., to Claude-3.7-Sonnet) improved consistency for some users. Try this if rules are spotty.
• Update or Rollback Versions: If on 1.0.0, upgrading to the latest version (like 1.1.3) or briefly downgrading and re-upgrading resolved issues. Always check for updates in Cursor’s settings.

Key Takeaways for Smooth Sailing

From my journey, this bug stems from initialization glitches in newer Cursor versions. To avoid headaches, make restarting your first troubleshooting step, confirm you’re in Agent mode, and keep your IDE updated. These workarounds saved my workflow, and now my project rules apply reliably, boosting productivity in AI-assisted coding.