diff --git a/src/@types/vscode.proposed.chatParticipantAdditions.d.ts b/src/@types/vscode.proposed.chatParticipantAdditions.d.ts
index 772d2fdf90..a07171f511 100644
--- a/src/@types/vscode.proposed.chatParticipantAdditions.d.ts
+++ b/src/@types/vscode.proposed.chatParticipantAdditions.d.ts
@@ -164,10 +164,10 @@ declare module 'vscode' {
 	/**
 	 * A specialized progress part for displaying thinking/reasoning steps.
 	 */
-	export class ChatResponseThinkingProgressPart extends ChatResponseProgressPart {
-		value: string;
+	export class ChatResponseThinkingProgressPart {
+		value: string | string[];
 		id?: string;
-		metadata?: string;
+		metadata?: { readonly [key: string]: any };
 		task?: (progress: Progress<LanguageModelThinkingPart>) => Thenable<string | void>;
 
 		/**
@@ -175,7 +175,7 @@ declare module 'vscode' {
 		 * @param value An initial progress message
 		 * @param task A task that will emit thinking parts during its execution
 		 */
-		constructor(value: string, id?: string, metadata?: string, task?: (progress: Progress<LanguageModelThinkingPart>) => Thenable<string | void>);
+		constructor(value: string | string[], id?: string, metadata?: { readonly [key: string]: any }, task?: (progress: Progress<LanguageModelThinkingPart>) => Thenable<string | void>);
 	}
 
 	export class ChatResponseReferencePart2 {
@@ -328,18 +328,18 @@ declare module 'vscode' {
 	}
 
 	export type ThinkingDelta = {
-		text?: string;
+		text?: string | string[];
 		id: string;
-		metadata?: string;
+		metadata?: { readonly [key: string]: any };
 	} | {
-		text?: string;
+		text?: string | string[];
 		id?: string;
-		metadata: string;
+		metadata: { readonly [key: string]: any };
 	} |
 	{
-		text: string;
+		text: string | string[];
 		id?: string;
-		metadata?: string;
+		metadata?: { readonly [key: string]: any };
 	};
 
 	export enum ChatResponseClearToPreviousToolInvocationReason {
diff --git a/src/@types/vscode.proposed.chatParticipantPrivate.d.ts b/src/@types/vscode.proposed.chatParticipantPrivate.d.ts
index 5e8b337772..66ae4a6310 100644
--- a/src/@types/vscode.proposed.chatParticipantPrivate.d.ts
+++ b/src/@types/vscode.proposed.chatParticipantPrivate.d.ts
@@ -183,6 +183,8 @@ declare module 'vscode' {
 		isQuotaExceeded?: boolean;
 
 		level?: ChatErrorLevel;
+
+		code?: string;
 	}
 
 	export namespace chat {
diff --git a/src/@types/vscode.proposed.languageModelDataPart.d.ts b/src/@types/vscode.proposed.languageModelDataPart.d.ts
index d2cd676400..4d491a66ca 100644
--- a/src/@types/vscode.proposed.languageModelDataPart.d.ts
+++ b/src/@types/vscode.proposed.languageModelDataPart.d.ts
@@ -42,7 +42,7 @@ declare module 'vscode' {
 		 * A string or heterogeneous array of things that a message can contain as content. Some parts may be message-type
 		 * specific for some models.
 		 */
-		content: Array<LanguageModelTextPart | LanguageModelToolResultPart2 | LanguageModelToolCallPart | LanguageModelDataPart>;
+		content: Array<LanguageModelTextPart | LanguageModelToolResultPart2 | LanguageModelToolCallPart | LanguageModelDataPart | LanguageModelThinkingPart>;
 
 		/**
 		 * The optional name of a user for this message.
@@ -56,7 +56,7 @@ declare module 'vscode' {
 		 * @param content The content of the message.
 		 * @param name The optional name of a user for the message.
 		 */
-		constructor(role: LanguageModelChatMessageRole, content: string | Array<LanguageModelTextPart | LanguageModelToolResultPart2 | LanguageModelToolCallPart | LanguageModelDataPart>, name?: string);
+		constructor(role: LanguageModelChatMessageRole, content: string | Array<LanguageModelTextPart | LanguageModelToolResultPart2 | LanguageModelToolCallPart | LanguageModelDataPart | LanguageModelThinkingPart>, name?: string);
 	}
 
 	/**