diff --git a/package.json b/package.json
index 121adffe67..8ee59c8d9c 100644
--- a/package.json
+++ b/package.json
@@ -36,6 +36,7 @@
 		"quickDiffProvider",
 		"remoteCodingAgents",
 		"shareProvider",
+		"tabInputMultiDiff",
 		"tokenInformation",
 		"treeItemMarkdownLabel",
 		"treeViewMarkdownMessage"
diff --git a/src/@types/vscode.proposed.chatParticipantAdditions.d.ts b/src/@types/vscode.proposed.chatParticipantAdditions.d.ts
index 71520fa1ec..aa7001a3d2 100644
--- a/src/@types/vscode.proposed.chatParticipantAdditions.d.ts
+++ b/src/@types/vscode.proposed.chatParticipantAdditions.d.ts
@@ -105,6 +105,7 @@ declare module 'vscode' {
 		isComplete?: boolean;
 		toolSpecificData?: ChatTerminalToolInvocationData;
 		fromSubAgent?: boolean;
+		presentation?: 'hidden' | 'hiddenAfterComplete' | undefined;
 
 		constructor(toolName: string, toolCallId: string, isError?: boolean);
 	}
diff --git a/src/@types/vscode.proposed.chatSessionsProvider.d.ts b/src/@types/vscode.proposed.chatSessionsProvider.d.ts
index bd4e624430..772fc387b9 100644
--- a/src/@types/vscode.proposed.chatSessionsProvider.d.ts
+++ b/src/@types/vscode.proposed.chatSessionsProvider.d.ts
@@ -95,6 +95,11 @@ declare module 'vscode' {
 		 */
 		description?: string | MarkdownString;
 
+		/**
+		 * An optional badge that provides additional context about the chat session.
+		 */
+		badge?: string | MarkdownString;
+
 		/**
 		 * An optional status indicating the current state of the session.
 		 */
diff --git a/src/@types/vscode.proposed.tabInputMultiDiff.d.ts b/src/@types/vscode.proposed.tabInputMultiDiff.d.ts
new file mode 100644
index 0000000000..242ebf4ada
--- /dev/null
+++ b/src/@types/vscode.proposed.tabInputMultiDiff.d.ts
@@ -0,0 +1,22 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+// https://github.com/microsoft/vscode/issues/206411
+
+declare module 'vscode' {
+
+	export class TabInputTextMultiDiff {
+
+		readonly textDiffs: TabInputTextDiff[];
+
+		constructor(textDiffs: TabInputTextDiff[]);
+	}
+
+	export interface Tab {
+
+		readonly input: TabInputText | TabInputTextDiff | TabInputTextMultiDiff | TabInputCustom | TabInputWebview | TabInputNotebook | TabInputNotebookDiff | TabInputTerminal | unknown;
+
+	}
+}
diff --git a/src/view/reviewManager.ts b/src/view/reviewManager.ts
index b9c31fac14..c5fff04131 100644
--- a/src/view/reviewManager.ts
+++ b/src/view/reviewManager.ts
@@ -675,7 +675,27 @@ export class ReviewManager extends Disposable {
 		}
 	}
 
+	private async _closeOutdatedMultiDiffEditors(pullRequest: PullRequestModel): Promise<void> {
+		// Close any multidiff editors for this PR that may be outdated
+		const multiDiffLabel = vscode.l10n.t('Changes in Pull Request #{0}', pullRequest.number);
+
+		const closePromises: Promise<boolean>[] = [];
+		for (const tabGroup of vscode.window.tabGroups.all) {
+			for (const tab of tabGroup.tabs) {
+				// Check if this is a TabInputTextMultiDiff with matching label
+				if (tab.input instanceof vscode.TabInputTextMultiDiff && tab.label.startsWith(multiDiffLabel)) {
+					Logger.appendLine(`Closing outdated multidiff editor for PR #${pullRequest.number}`, this.id);
+					closePromises.push(Promise.resolve(vscode.window.tabGroups.close(tab)));
+				}
+			}
+		}
+		await Promise.all(closePromises);
+	}
+
 	public async _upgradePullRequestEditors(pullRequest: PullRequestModel) {
+		// Close any outdated multidiff editors first
+		await this._closeOutdatedMultiDiffEditors(pullRequest);
+
 		// Go through all open editors and find pr scheme editors that belong to the active pull request.
 		// Close the editors, and reopen them from the pull request.
 		const reopenFilenames: Set<[PRUriParams, PRUriParams]> = new Set();