First check whether the rule was loaded at all. Project rules under .cursor/rules/ use the .mdc extension. An ordinary .md file in that folder is not equivalent. Cursor also supports AGENTS.md for plain-text instructions. 1
Reduce the test to one rule
Create the rule through Cursor’s settings or inspect its metadata. For a diagnostic test, use one harmless instruction that always applies:
---
description: Project test command
alwaysApply: true
---
Use the existing test command from package.json.
Save it as something like .cursor/rules/tests.mdc and test in a fresh conversation, without several long, competing rule files.
For a rule intended only for selected files, check the file pattern and the folder opened as the workspace. File-scoped rules, description-based selection and manually selected rules have different activation conditions. 12
Loading is not the same as compliance
A visible rule that was ignored is a different problem from an instruction the agent never received. Check for contradictory legacy files rather than adding another copy of the same rule. Do not disable privacy protections as a troubleshooting shortcut.
Finish with an observable test and inspect the actual command or diff. Rules guide the agent; they do not replace automated checks or code review.
