diff --git a/src/vs/vscode.proposed.d.ts b/src/vs/vscode.proposed.d.ts
index 2d7b21802c965..f571826403c3c 100644
--- a/src/vs/vscode.proposed.d.ts
+++ b/src/vs/vscode.proposed.d.ts
@@ -60,7 +60,7 @@ declare module 'vscode' {
 
 		/**
 		 * The [command](#Command) which should be run when the tree item
-		 * is selected
+		 * is selected. This command is called with the model representing this item as first argument.
 		 */
 		readonly command?: Command;