diff --git a/src/vs/workbench/contrib/chat/browser/attachments/promptInstructions/promptInstructionsCollectionWidget.ts b/src/vs/workbench/contrib/chat/browser/attachments/promptInstructions/promptInstructionsCollectionWidget.ts
index a6cbf93700a8a..7c0fb3d96d212 100644
--- a/src/vs/workbench/contrib/chat/browser/attachments/promptInstructions/promptInstructionsCollectionWidget.ts
+++ b/src/vs/workbench/contrib/chat/browser/attachments/promptInstructions/promptInstructionsCollectionWidget.ts
@@ -93,7 +93,7 @@ export class PromptInstructionsAttachmentsCollectionWidget extends Disposable {
 		this.render = this.render.bind(this);
 
 		// when a new attachment model is added, create a new child widget for it
-		this.model.onAdd((attachment) => {
+		this._register(this.model.onAdd((attachment) => {
 			const widget = this.initService.createInstance(
 				InstructionsAttachmentWidget,
 				attachment,
@@ -114,7 +114,7 @@ export class PromptInstructionsAttachmentsCollectionWidget extends Disposable {
 
 			// fire the event to notify about the change in the number of attachments
 			this._onAttachmentsCountChange.fire();
-		});
+		}));
 	}
 
 	/**
diff --git a/src/vs/workbench/contrib/chat/browser/chatAttachmentModel.ts b/src/vs/workbench/contrib/chat/browser/chatAttachmentModel.ts
index ac4e1c5ab33bb..223c4d5b4ddab 100644
--- a/src/vs/workbench/contrib/chat/browser/chatAttachmentModel.ts
+++ b/src/vs/workbench/contrib/chat/browser/chatAttachmentModel.ts
@@ -42,9 +42,19 @@ export class ChatAttachmentModel extends Disposable {
 
 		this.promptInstructions = this._register(
 			this.initService.createInstance(ChatPromptAttachmentsCollection),
-		).onUpdate(() => {
-			this._onDidChange.fire({ added: [], deleted: [], updated: [] });
-		});
+		);
+
+		this._register(
+			this.promptInstructions.onAdd(() => {
+				this._onDidChange.fire({ added: [], deleted: [], updated: [] });
+			}),
+		);
+
+		this._register(
+			this.promptInstructions.onRemove(() => {
+				this._onDidChange.fire({ added: [], deleted: [], updated: [] });
+			}),
+		);
 	}
 
 	private _attachments = new Map<string, IChatRequestVariableEntry>();
diff --git a/src/vs/workbench/contrib/chat/browser/chatAttachmentModel/chatPromptAttachmentsCollection.ts b/src/vs/workbench/contrib/chat/browser/chatAttachmentModel/chatPromptAttachmentsCollection.ts
index a1817f40e41ef..f88086c5f0e87 100644
--- a/src/vs/workbench/contrib/chat/browser/chatAttachmentModel/chatPromptAttachmentsCollection.ts
+++ b/src/vs/workbench/contrib/chat/browser/chatAttachmentModel/chatPromptAttachmentsCollection.ts
@@ -86,6 +86,37 @@ export const toChatVariable = (
  * See {@linkcode ChatPromptAttachmentModel} for individual attachment.
  */
 export class ChatPromptAttachmentsCollection extends Disposable {
+	/**
+	 * Event that fires then this model is updated.
+	 *
+	 * See {@linkcode onUpdate}.
+	 */
+	protected _onUpdate = this._register(new Emitter<void>());
+	/**
+	 * Subscribe to the `onUpdate` event.
+	 */
+	public onUpdate = this._onUpdate.event;
+
+	/**
+	 * Event that fires when a new prompt instruction attachment is added.
+	 * See {@linkcode onAdd}.
+	 */
+	protected _onAdd = this._register(new Emitter<ChatPromptAttachmentModel>());
+	/**
+	 * The `onAdd` event fires when a new prompt instruction attachment is added.
+	 */
+	public onAdd = this._onAdd.event;
+
+	/**
+	 * Event that fires when a new prompt instruction attachment is removed.
+	 * See {@linkcode onRemove}.
+	 */
+	protected _onRemove = this._register(new Emitter<ChatPromptAttachmentModel>());
+	/**
+	 * The `onRemove` event fires when a new prompt instruction attachment is removed.
+	 */
+	public onRemove = this._onRemove.event;
+
 	/**
 	 * List of all prompt instruction attachments.
 	 */
@@ -154,38 +185,6 @@ export class ChatPromptAttachmentsCollection extends Disposable {
 		);
 	}
 
-	/**
-	 * Event that fires then this model is updated.
-	 *
-	 * See {@linkcode onUpdate}.
-	 */
-	protected _onUpdate = this._register(new Emitter<void>());
-	/**
-	 * Subscribe to the `onUpdate` event.
-	 * @param callback Function to invoke on update.
-	 */
-	public onUpdate(callback: () => unknown): this {
-		this._register(this._onUpdate.event(callback));
-
-		return this;
-	}
-
-	/**
-	 * Event that fires when a new prompt instruction attachment is added.
-	 * See {@linkcode onAdd}.
-	 */
-	protected _onAdd = this._register(new Emitter<ChatPromptAttachmentModel>());
-	/**
-	 * The `onAdd` event fires when a new prompt instruction attachment is added.
-	 *
-	 * @param callback Function to invoke on add.
-	 */
-	public onAdd(callback: (attachment: ChatPromptAttachmentModel) => unknown): this {
-		this._register(this._onAdd.event(callback));
-
-		return this;
-	}
-
 	constructor(
 		@IInstantiationService private readonly initService: IInstantiationService,
 		@IConfigurationService private readonly configService: IConfigurationService,
@@ -214,6 +213,7 @@ export class ChatPromptAttachmentsCollection extends Disposable {
 				//       alternative results in an infinite loop of calling this callback
 				this.attachments.deleteAndLeak(uri.path);
 				this._onUpdate.fire();
+				this._onRemove.fire(instruction);
 			});
 
 		this.attachments.set(uri.path, instruction);