diff --git a/.cursor/rules/no-useless-duplication.mdc b/.cursor/rules/no-useless-duplication.mdc
new file mode 100644
index 0000000..e2dee36
--- /dev/null
+++ b/.cursor/rules/no-useless-duplication.mdc
@@ -0,0 +1,6 @@
+---
+description: 
+globs: 
+alwaysApply: true
+---
+Do not duplicate code unless you have a very good reason to do so. It is important that the same logic is not duplicated multiple times
\ No newline at end of file
diff --git a/AI_INSTRUCTIONS.md b/AI_INSTRUCTIONS.md
index 72e06ac..97e84f9 100644
--- a/AI_INSTRUCTIONS.md
+++ b/AI_INSTRUCTIONS.md
@@ -2,3 +2,4 @@
 
 - If you want to run tests, only ever run them as "pnpm format && pnpm lint && pnpm test".
 - Don't leave comments that don't add value
+- Do not duplicate code unless you have a very good reason to do so. It is important that the same logic is not duplicated multiple times