diff --git a/types/observer-mixin.d.ts b/types/observer-mixin.d.ts
index 769a00bc5..6a020e6cd 100644
--- a/types/observer-mixin.d.ts
+++ b/types/observer-mixin.d.ts
@@ -5,7 +5,11 @@
 
 import {Callback, PromiseOrVoid} from './common';
 
-export type Listener = (ctx: object, next: (err?: any) => void) => void;
+export interface OperationHookContext {
+  [property: string]: any;
+}
+
+export type Listener = (ctx: OperationHookContext, next: (err?: any) => void) => void;
 
 export interface ObserverMixin {
   /**
diff --git a/types/persisted-model.d.ts b/types/persisted-model.d.ts
index a5e1b5cb1..dd4af1ad8 100644
--- a/types/persisted-model.d.ts
+++ b/types/persisted-model.d.ts
@@ -5,6 +5,7 @@
 
 import {Callback, Options, PromiseOrVoid} from './common';
 import {ModelBase, ModelData} from './model';
+import {Listener} from './observer-mixin';
 import {Filter, Where} from './query';
 
 /**
@@ -519,6 +520,10 @@ export declare class PersistedModel extends ModelBase {
    * @returns {String} The `id` property name
    */
   static getIdName(): string;
+
+  definePersistedModel<T>(entityClass: T): PersistedModel;
+
+  static observe(operation: string, handler: Listener): void;
 }
 
 export type PersistedModelClass = typeof PersistedModel;