Emit runtime deprecation warning from mgt-element

packages/mgt-element/src/components/baseComponent.ts

@@ -11,6 +11,7 @@ import { ProviderState } from '../providers/IProvider';
 import { Providers } from '../providers/Providers';
 import { LocalizationHelper } from '../utils/LocalizationHelper';
 import { PACKAGE_VERSION } from '../utils/version';
+import { emitDeprecationWarning } from '../utils/deprecationWarning';
 
 /**
  * Defines media query based on component width
@@ -128,6 +129,7 @@ export abstract class MgtBaseComponent extends LitElement {
 
   constructor() {
     super();
+    emitDeprecationWarning();
     this.handleDirectionChanged();
     this.handleLocalizationChanged();
   }

packages/mgt-element/src/components/baseTaskComponent.ts

@@ -13,6 +13,7 @@ import { ProviderState } from '../providers/IProvider';
 import { Providers } from '../providers/Providers';
 import { LocalizationHelper } from '../utils/LocalizationHelper';
 import { PACKAGE_VERSION } from '../utils/version';
+import { emitDeprecationWarning } from '../utils/deprecationWarning';
 import { ComponentMediaQuery } from './baseComponent';
 
 /**
@@ -96,6 +97,7 @@ export abstract class MgtBaseTaskComponent extends LitElement {
 
   constructor() {
     super();
+    emitDeprecationWarning();
     this.handleDirectionChanged();
     this.handleLocalizationChanged();
   }

packages/mgt-element/src/utils/deprecationWarning.ts

@@ -0,0 +1,33 @@
+/**
+ * -------------------------------------------------------------------------------------------
+ * Copyright (c) Microsoft Corporation.  All Rights Reserved.  Licensed under the MIT License.
+ * See License in the project root for license information.
+ * -------------------------------------------------------------------------------------------
+ */
+
+let hasWarned = false;
+
+/**
+ * Emits a one-time console warning informing consumers that the
+ * Microsoft Graph Toolkit has been retired.
+ *
+ * The warning is emitted at most once per runtime, and any failure to
+ * write to the console is swallowed so this can never break a host app.
+ */
+export const emitDeprecationWarning = (): void => {
+  if (hasWarned) {
+    return;
+  }
+  hasWarned = true;
+
+  try {
+    console.warn(
+      '🦒: The Microsoft Graph Toolkit was retired on August 28, 2026 and is no longer maintained. ' +
+        'This package will receive no further updates. ' +
+        'If you would like to continue using or maintaining MGT, you are welcome to fork the repository: ' +
+        'https://github.com/microsoftgraph/microsoft-graph-toolkit'
+    );
+  } catch {
+    // Never allow logging to break a host application.
+  }
+};