diff --git a/src/vscode-dts/vscode.proposed.terminalShellIntegration.d.ts b/src/vscode-dts/vscode.proposed.terminalShellIntegration.d.ts
index aad16bf615297..c2cb186395330 100644
--- a/src/vscode-dts/vscode.proposed.terminalShellIntegration.d.ts
+++ b/src/vscode-dts/vscode.proposed.terminalShellIntegration.d.ts
@@ -25,6 +25,7 @@ declare module 'vscode' {
 		 * - It may contain line continuation characters and/or parts of the right prompt.
 		 * - It may be inaccurate if the shell integration does not support command line reporting.
 		 */
+		// TODO@API undefined makes using this hard?
 		readonly commandLine: string | undefined;
 
 		/**