diff --git a/src/vs/workbench/api/browser/mainThreadEditorTabs.ts b/src/vs/workbench/api/browser/mainThreadEditorTabs.ts
index af3afd53c47..f8683908975 100644
--- a/src/vs/workbench/api/browser/mainThreadEditorTabs.ts
+++ b/src/vs/workbench/api/browser/mainThreadEditorTabs.ts
@@ -5,7 +5,7 @@
 
 import { DisposableStore } from 'vs/base/common/lifecycle';
 import { URI } from 'vs/base/common/uri';
-import { ExtHostContext, IExtHostEditorTabsShape, MainContext, IEditorTabDto, IEditorTabGroupDto } from 'vs/workbench/api/common/extHost.protocol';
+import { ExtHostContext, IExtHostEditorTabsShape, MainContext, IEditorTabDto, IEditorTabGroupDto, TabKind } from 'vs/workbench/api/common/extHost.protocol';
 import { extHostNamedCustomer, IExtHostContext } from 'vs/workbench/services/extensions/common/extHostCustomers';
 import { EditorResourceAccessor, IUntypedEditorInput, SideBySideEditor, DEFAULT_EDITOR_ASSOCIATION, GroupModelChangeKind } from 'vs/workbench/common/editor';
 import { DiffEditorInput } from 'vs/workbench/common/editor/diffEditorInput';
@@ -48,12 +48,14 @@ export class MainThreadEditorTabs {
 	 */
 	private _buildTabObject(editor: EditorInput, group: IEditorGroup): IEditorTabDto {
 		// Even though the id isn't a diff / sideBySide on the main side we need to let the ext host know what type of editor it is
-		const editorId = editor instanceof DiffEditorInput ? 'diff' : editor instanceof SideBySideEditorInput ? 'sideBySide' : editor.editorId;
+		const editorId = editor.editorId;
+		const tabKind = editor instanceof DiffEditorInput ? TabKind.DIFF : editor instanceof SideBySideEditorInput ? TabKind.SIDEBYSIDE : TabKind.SINGULAR;
 		const tab: IEditorTabDto = {
 			viewColumn: editorGroupToColumn(this._editorGroupsService, group),
 			label: editor.getName(),
 			resource: editor instanceof SideBySideEditorInput ? EditorResourceAccessor.getCanonicalUri(editor, { supportSideBySide: SideBySideEditor.PRIMARY }) : EditorResourceAccessor.getCanonicalUri(editor),
 			editorId,
+			kind: tabKind,
 			additionalResourcesAndViewIds: [],
 			isActive: group.isActive(editor),
 			isDirty: editor.isDirty()
diff --git a/src/vs/workbench/api/common/extHost.api.impl.ts b/src/vs/workbench/api/common/extHost.api.impl.ts
index de7580fc921..86bc738b792 100644
--- a/src/vs/workbench/api/common/extHost.api.impl.ts
+++ b/src/vs/workbench/api/common/extHost.api.impl.ts
@@ -13,7 +13,7 @@ import { OverviewRulerLane } from 'vs/editor/common/model';
 import * as languageConfiguration from 'vs/editor/common/languages/languageConfiguration';
 import { score } from 'vs/editor/common/languageSelector';
 import * as files from 'vs/platform/files/common/files';
-import { ExtHostContext, MainContext, CandidatePortSource, ExtHostLogLevelServiceShape } from 'vs/workbench/api/common/extHost.protocol';
+import { ExtHostContext, MainContext, CandidatePortSource, ExtHostLogLevelServiceShape, TabKind } from 'vs/workbench/api/common/extHost.protocol';
 import { UIKind } from 'vs/workbench/services/extensions/common/extensionHostProtocol';
 import { ExtHostApiCommands } from 'vs/workbench/api/common/extHostApiCommands';
 import { ExtHostClipboard } from 'vs/workbench/api/common/extHostClipboard';
@@ -1249,6 +1249,7 @@ export function createApiFactoryAndRegisterActors(accessor: ServicesAccessor): I
 			SymbolInformation: extHostTypes.SymbolInformation,
 			SymbolKind: extHostTypes.SymbolKind,
 			SymbolTag: extHostTypes.SymbolTag,
+			TabKind: TabKind,
 			Task: extHostTypes.Task,
 			TaskGroup: extHostTypes.TaskGroup,
 			TaskPanelKind: extHostTypes.TaskPanelKind,
diff --git a/src/vs/workbench/api/common/extHost.protocol.ts b/src/vs/workbench/api/common/extHost.protocol.ts
index ea632c99395..f5c4a615e34 100644
--- a/src/vs/workbench/api/common/extHost.protocol.ts
+++ b/src/vs/workbench/api/common/extHost.protocol.ts
@@ -625,6 +625,13 @@ export interface IEditorTabGroupDto {
 	groupId: number;
 }
 
+export enum TabKind {
+	SINGULAR = 0,
+	DIFF = 1,
+	SIDEBYSIDE = 2,
+	OTHER = 3
+}
+
 export interface IEditorTabDto {
 	viewColumn: EditorGroupColumn;
 	label: string;
@@ -632,6 +639,7 @@ export interface IEditorTabDto {
 	editorId?: string;
 	isActive: boolean;
 	isDirty: boolean;
+	kind: TabKind;
 	additionalResourcesAndViewIds: { resource?: UriComponents; viewId?: string }[];
 }
 
diff --git a/src/vs/workbench/api/common/extHostEditorTabs.ts b/src/vs/workbench/api/common/extHostEditorTabs.ts
index 1f780100c5e..29a2bfb42ec 100644
--- a/src/vs/workbench/api/common/extHostEditorTabs.ts
+++ b/src/vs/workbench/api/common/extHostEditorTabs.ts
@@ -5,7 +5,7 @@
 
 import type * as vscode from 'vscode';
 import * as typeConverters from 'vs/workbench/api/common/extHostTypeConverters';
-import { IEditorTabDto, IEditorTabGroupDto, IExtHostEditorTabsShape, MainContext, MainThreadEditorTabsShape } from 'vs/workbench/api/common/extHost.protocol';
+import { IEditorTabDto, IEditorTabGroupDto, IExtHostEditorTabsShape, MainContext, MainThreadEditorTabsShape, TabKind } from 'vs/workbench/api/common/extHost.protocol';
 import { URI } from 'vs/base/common/uri';
 import { Emitter, Event } from 'vs/base/common/event';
 import { createDecorator } from 'vs/platform/instantiation/common/instantiation';
@@ -17,6 +17,7 @@ export interface IEditorTab {
 	resource: vscode.Uri | undefined;
 	viewId: string | undefined;
 	isActive: boolean;
+	kind: TabKind;
 	isDirty: boolean;
 	additionalResourcesAndViewIds: { resource: vscode.Uri | undefined; viewId: string | undefined }[];
 	move(index: number, viewColumn: ViewColumn): Promise<void>;
@@ -92,6 +93,7 @@ export class ExtHostEditorTabs implements IExtHostEditorTabs {
 			additionalResourcesAndViewIds: tabDto.additionalResourcesAndViewIds.map(({ resource, viewId }) => ({ resource: URI.revive(resource), viewId })),
 			viewId: tabDto.editorId,
 			isActive: tabDto.isActive,
+			kind: tabDto.kind,
 			isDirty: tabDto.isDirty,
 			move: async (index: number, viewColumn: ViewColumn) => {
 				this._proxy.$moveTab(tabDto, index, typeConverters.ViewColumn.from(viewColumn));
diff --git a/src/vscode-dts/vscode.proposed.tabs.d.ts b/src/vscode-dts/vscode.proposed.tabs.d.ts
index 09fb65e6d7d..3f2ed50f451 100644
--- a/src/vscode-dts/vscode.proposed.tabs.d.ts
+++ b/src/vscode-dts/vscode.proposed.tabs.d.ts
@@ -7,6 +7,13 @@ declare module 'vscode' {
 
 	// https://github.com/Microsoft/vscode/issues/15178
 
+	export enum TabKind {
+		SINGULAR = 0,
+		DIFF = 1,
+		SIDEBYSIDE = 2,
+		OTHER = 3
+	}
+
 	/**
 	 * Represents a tab within the window
 	 */
@@ -55,6 +62,11 @@ declare module 'vscode' {
 		 */
 		readonly isDirty: boolean;
 
+		/**
+		 * Indicates the type of tab it is.
+		 */
+		readonly kind: TabKind;
+
 		/**
 		 * Moves a tab to the given index within the column.
 		 * If the index is out of range, the tab will be moved to the end of the column.