diff --git a/.voidrules b/.voidrules
index 59586971..6c655134 100644
--- a/.voidrules
+++ b/.voidrules
@@ -10,3 +10,5 @@ In typescript, do NOT cast to types if not neccessary. NEVER lazily cast to 'any
 Do not add or remove semicolons to any of my files. Just go with convention and make the least number of changes.
 
 Never modify files outside src/vs/workbench/contrib/void without consulting with the user first.
+
+All types that map from a value A to B should be called bOfA. For example, if you create a hashmap that goes from toolId to toolName, it should be called toolNameOfToolId, etc.