Cursor can't find manual rule

Bug Reports
1

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

I reference a MDC file by tagging it in chat. The chat editor helpfully finds and links the file. Then the agent reports it can’t find any such rule. I know the LLM is non-deterministic but this looks like a tool response that says “No rules found” separate from the regular chat.

This is an Apply Manually rule btw. It does seem to find other rules and use them.

Steps to Reproduce

Make a .mdc file in .cursor/rules/project.
Mark it as Apply Manually in the editor.
Then tag it in a chat with @.
The agent then reports that it can’t find the rule.

Expected Behavior

I expect that tagging in a MDC file will let cursor add the rule to the context so that the LLM will follow the rule.

Screenshots / Screen Recordings

Screenshot 2025-10-24 234509.png
Screenshot 2025-10-24 234509.png535×395 10.8 KB

Operating System

Windows 10/11

Current Cursor Version (Menu → About Cursor → Copy)

Version: 1.7.54 (user setup)
VSCode Version: 1.99.3
Commit: 5c17eb2968a37f66bc6662f48d6356a100b67be0
Date: 2025-10-21T19:07:38.476Z
Electron: 34.5.8
Chromium: 132.0.6834.210
Node.js: 20.19.1
V8: 13.2.152.41-electron.0
OS: Windows_NT x64 10.0.26100

For AI issues: which model did you use?

claude-4.5-sonnet MAX

For AI issues: add Request ID with privacy disabled

21929b90-3c87-4ff7-a647-65c179a540cc

Does this stop you from using Cursor

No - Cursor works, but with this issue

2

Screenshot showing the rule file:

image
image938×441 24.9 KB

3

Hey, thanks for the report. This looks like a potential bug where the UI finds the rule, but the agent’s tool call fails.

A few questions to help diagnose it:

  1. How did you open the project? Via File > Open Folder or via the CLI cursor . / right‑click “Open with Cursor”? There’s a known issue: on Windows, rules may load incorrectly when opened via CLI/right‑click.

  2. Do other manual rules work when @-mentioning, or is it only this file?

  3. If you’re opening via CLI/right‑click, try using File > Open Folder as a temporary workaround and let us know if it still reproduces.

4

Thanks for the quick followup!

  1. I open Cursor first and then open the folder. Additional context I forgot to mention: this is in a dev container.

  2. I made a minimum reproduction and confirmed that it’s not just this one rule.

    image
    image1868×389 30.3 KB

6

Thanks for the info, that’s very helpful.

1 Like