diff --git a/src/vs/workbench/api/common/extHost.protocol.ts b/src/vs/workbench/api/common/extHost.protocol.ts
index 6925867c334..2bef4d37752 100644
--- a/src/vs/workbench/api/common/extHost.protocol.ts
+++ b/src/vs/workbench/api/common/extHost.protocol.ts
@@ -620,6 +620,11 @@ export const enum TabInputKind {
 	TerminalEditorInput
 }
 
+export const enum TabModelOperationKind {
+	TAB_OPEN,
+	TAB_CLOSE
+}
+
 export interface UnknownInputDto {
 	kind: TabInputKind.UnknownInput;
 }
@@ -680,6 +685,12 @@ export interface IEditorTabGroupDto {
 	groupId: number;
 }
 
+export interface TabOperation {
+	readonly kind: TabModelOperationKind.TAB_OPEN | TabModelOperationKind.TAB_CLOSE;
+	readonly index: number;
+	readonly tab: IEditorTabDto;
+}
+
 export interface IEditorTabDto {
 	id: string;
 	label: string;