diff --git a/vscode.proposed.d.ts b/vscode.proposed.d.ts
index abce892ee3..7b14a50952 100644
--- a/vscode.proposed.d.ts
+++ b/vscode.proposed.d.ts
@@ -143,6 +143,16 @@ declare module 'vscode' {
 		 */
 		lastRunDuration?: number;
 
+		/**
+		 * Whether a code cell's editor is collapsed
+		 */
+		inputCollapsed?: boolean;
+
+		/**
+		 * Whether a code cell's outputs are collapsed
+		 */
+		outputCollapsed?: boolean;
+
 		/**
 		 * Additional attributes of a cell metadata.
 		 */