diff --git a/PROJECT_GUIDELINES.md b/PROJECT_GUIDELINES.md
index 478c36f..0da0f26 100644
--- a/PROJECT_GUIDELINES.md
+++ b/PROJECT_GUIDELINES.md
@@ -55,6 +55,7 @@
   - Run `git push` and wait for completion
   - Never use `&&` to chain git commands together
 - ✅ **Make good organized git commits for the entire project (not just what you changed) and push - run git add, commit, push sequentially as separate commands, no need to repeatedly check status**
+- ✅ **Indentation is always 2 spaces unless the language prohibits it**
 
 ### Cascading Fix-up Pattern (PROHIBITED)