diff --git a/lib/command/definitions.js b/lib/command/definitions.js
index 8a4a9bbca..20f0be26c 100644
--- a/lib/command/definitions.js
+++ b/lib/command/definitions.js
@@ -38,6 +38,46 @@ interface ILocator {
   ios?: string;
 }
 
+declare class Helper {
+  /** Abstract method to provide required config options */
+  static _config(): any;
+  /** Abstract method to validate config */
+  _validateConfig<T>(config: T): T;
+  /** Sets config for current test */
+  _setConfig(opts: any): void;
+  /** Hook executed before all tests */
+  _init(): void
+  /** Hook executed before each test. */
+  _before(): void
+  /** Hook executed after each test */
+  _after(): void
+  /**
+   * Hook provides a test details
+   * Executed in the very beginning of a test
+   */
+  _test(test): void
+  /** Hook executed after each passed test */
+  _passed(test: () => void): void
+  /** Hook executed after each failed test */
+  _failed(test: () => void): void
+  /** Hook executed before each step */
+  _beforeStep(step: () => void): void
+  /** Hook executed after each step */
+  _afterStep(step: () => void): void
+  /** Hook executed before each suite */
+  _beforeSuite(suite: () => void): void
+  /** Hook executed after each suite */
+  _afterSuite(suite: () => void): void
+  /** Hook executed after all tests are executed */
+  _finishTest(suite: () => void): void
+  /**Access another configured helper: `this.helpers['AnotherHelper']` */
+  get helpers(): any
+  /** Print debug message to console (outputs only in debug mode) */
+  debug(msg: string): void
+
+  debugSection(section: string, msg: string): void
+}
+
 declare class Locator implements ILocator {
   xpath?: string;
   css?: string;
@@ -64,8 +104,12 @@ declare class Locator implements ILocator {
 
 declare function actor(customSteps?: {}): CodeceptJS.{{I}};
 declare function Feature(title: string, opts?: {}): FeatureConfig;
-declare function Scenario(title: string, callback: ICodeceptCallback): ScenarioConfig;
-declare function Scenario(title: string, opts: {}, callback: ICodeceptCallback): ScenarioConfig;
+declare const Scenario: {
+	(title: string, callback: ICodeceptCallback): ScenarioConfig;
+	(title: string, opts: {}, callback: ICodeceptCallback): ScenarioConfig;
+	only(title: string, callback: ICodeceptCallback): ScenarioConfig;
+	only(title: string, opts: {}, callback: ICodeceptCallback): ScenarioConfig;
+}
 declare function xScenario(title: string, callback: ICodeceptCallback): ScenarioConfig;
 declare function xScenario(title: string, opts: {}, callback: ICodeceptCallback): ScenarioConfig;
 declare function Data(data: any): any;