diff --git a/ckeditor/ckeditor-tests.ts b/ckeditor/ckeditor-tests.ts
index 976b85717..326fe92c6 100644
--- a/ckeditor/ckeditor-tests.ts
+++ b/ckeditor/ckeditor-tests.ts
@@ -251,4 +251,40 @@ function test_dom_window() {
     var size = win.getViewPaneSize();
     alert(size.width);
     alert(size.height);
-}
\ No newline at end of file
+}
+
+function test_adding_dialog_by_path() {
+    CKEDITOR.dialog.add( 'abbrDialog', this.path + 'dialogs/abbr.js' );
+}
+
+function test_adding_dialog_by_definition() {
+    CKEDITOR.dialog.add( 'abbrDialog', function ( editor: CKEDITOR.editor ) {
+        return {
+            title: 'Abbreviation Properties',
+            minWidth: 400,
+            minHeight: 200,
+
+            contents: [
+                {
+                    id: 'tab-basic',
+                    label: 'Basic Settings',
+                    elements: <any[]>[]
+                },
+                {
+                    id: 'tab-adv',
+                    label: 'Advanced Settings',
+                    elements: []
+                }
+            ]
+        };
+    });
+}
+
+function test_adding_plugin() {
+    CKEDITOR.plugins.add( 'abbr', {
+        icons: 'abbr',
+        init: function( editor: CKEDITOR.editor ) {
+            // empty logic
+        }
+    });
+}
diff --git a/ckeditor/ckeditor.d.ts b/ckeditor/ckeditor.d.ts
index a1bb1c481..6a0ed9775 100644
--- a/ckeditor/ckeditor.d.ts
+++ b/ckeditor/ckeditor.d.ts
@@ -619,6 +619,24 @@ declare module CKEDITOR {
             }
         }
 
+        interface IPluginDefinition {
+            hidpi?: boolean;
+            lang?: any; // should be string | string[]
+            requires?: any; // should be string | string[]a
+            afterInit?(editor: editor): any;
+            beforeInit?(editor: editor): any;
+            init?(editor: editor): any;
+            onLoad?(): any;
+        }
+
+        function add(name: string, definition?: IPluginDefinition): void;
+        function addExternal(name: string, path: string, fileName: string): void;
+        function get(name: string): any;
+        function getFilePath(name: string): string;
+        function getPath(name: string): string;
+        function load(name: string, callback: string, scope: any): void;
+        function setLang(pluginName: string, languageCode: string, languageEntries: any): void;
+
     }
 
 
@@ -963,4 +981,35 @@ declare module CKEDITOR {
         addFocusable(element: CKEDITOR.dom.element, index: number): void;
     }
 
+    module tools {
+        var callFunction: Function;
+    }
+
+    module dialog {
+        interface IDialogDefinition {
+            buttons?: any[];
+            contents?: any[];
+            height?: number;
+            minHeight?: number;
+            minWidth?: number;
+            onCancel?: Function;
+            onLoad?: Function;
+            onOk?: Function;
+            onShow?: Function;
+            resizable?: number;
+            title?: string;
+            width?: number;
+        }
+
+        function add(name: string, path: string): void;
+        function add(name: string, dialogDefinition: IDialogDefinition): void;
+        function addIframe(name: string, title: string, minWidth: number,
+            minHeight: number, onContentLoad: Function, userDefinition: any): void;
+        function addUIElement(typeName: string, builder: Function): void;
+        function cancelButton(): void;
+        function exists(name: string): void;
+        function getCurrent(): void;
+        function isTabEnabled(editor: editor, dialogName: string, tabName: string): boolean;
+        function okButton(): void;
+    }
 }