diff --git a/site/src/pages/AgentsPage/components/ChatActionsMenuItems.tsx b/site/src/pages/AgentsPage/components/ChatActionsMenuItems.tsx
index 84b35e4208..7cc0055150 100644
--- a/site/src/pages/AgentsPage/components/ChatActionsMenuItems.tsx
+++ b/site/src/pages/AgentsPage/components/ChatActionsMenuItems.tsx
@@ -1,6 +1,7 @@
 import {
 	ArchiveIcon,
 	ArchiveRestoreIcon,
+	GitForkIcon,
 	PinIcon,
 	PinOffIcon,
 	SquarePenIcon,
@@ -41,6 +42,9 @@ interface ChatActionsMenuItemsProps {
 	readonly isChildChat: boolean;
 	readonly hasWorkspace: boolean;
 	readonly isArchiving?: boolean;
+	readonly subagentCount?: number;
+	readonly isSubagentsExpanded?: boolean;
+	readonly onToggleSubagents?: () => void;
 	readonly onPinAgent?: () => void;
 	readonly onUnpinAgent?: () => void;
 	readonly onArchiveAgent: () => void;
@@ -58,6 +62,9 @@ export const ChatActionsMenuItems: FC<ChatActionsMenuItemsProps> = ({
 	isChildChat,
 	hasWorkspace,
 	isArchiving = false,
+	subagentCount = 0,
+	isSubagentsExpanded = false,
+	onToggleSubagents,
 	onPinAgent,
 	onUnpinAgent,
 	onArchiveAgent,
@@ -67,10 +74,20 @@ export const ChatActionsMenuItems: FC<ChatActionsMenuItemsProps> = ({
 	Item,
 	Separator,
 }) => {
+	const showSubagentsToggle = Boolean(onToggleSubagents) && subagentCount > 0;
 	const showPinAction =
 		!isArchived && !isChildChat && Boolean(onPinAgent && onUnpinAgent);
 	const showArchiveActions = !isArchived && !isChildChat;
 
+	const subagentToggle = showSubagentsToggle ? (
+		<Item onSelect={onToggleSubagents}>
+			<GitForkIcon className="size-3.5 rotate-180" />
+			{isSubagentsExpanded
+				? "Hide subagents"
+				: `Show subagents (${subagentCount})`}
+		</Item>
+	) : null;
+
 	return (
 		<>
 			{showPinAction && (
@@ -90,10 +107,13 @@ export const ChatActionsMenuItems: FC<ChatActionsMenuItemsProps> = ({
 			)}
 			{isArchived ? (
 				!isChildChat && (
-					<Item disabled={isArchiving} onSelect={onUnarchiveAgent}>
-						<ArchiveRestoreIcon className="size-3.5" />
-						Unarchive agent
-					</Item>
+					<>
+						<Item disabled={isArchiving} onSelect={onUnarchiveAgent}>
+							<ArchiveRestoreIcon className="size-3.5" />
+							Unarchive agent
+						</Item>
+						{subagentToggle}
+					</>
 				)
 			) : (
 				<>
@@ -103,9 +123,12 @@ export const ChatActionsMenuItems: FC<ChatActionsMenuItemsProps> = ({
 							Rename chat
 						</Item>
 					)}
+					{subagentToggle}
 					{showArchiveActions && (
 						<>
-							{(onOpenRenameDialog || showPinAction) && <Separator />}
+							{(onOpenRenameDialog || showPinAction || showSubagentsToggle) && (
+								<Separator />
+							)}
 							<Item
 								className="text-content-destructive focus:text-content-destructive"
 								disabled={isArchiving}
diff --git a/site/src/pages/AgentsPage/components/ChatsSidebar/ChatsSidebar.stories.tsx b/site/src/pages/AgentsPage/components/ChatsSidebar/ChatsSidebar.stories.tsx
index 958dc6f6cf..cbcbd3b35f 100644
--- a/site/src/pages/AgentsPage/components/ChatsSidebar/ChatsSidebar.stories.tsx
+++ b/site/src/pages/AgentsPage/components/ChatsSidebar/ChatsSidebar.stories.tsx
@@ -2007,6 +2007,86 @@ export const AgentWithWorkspaceMenuFull: Story = {
 	},
 };
 
+// A collapsed parent chat exposes a "Show subagents (N)" action in its
+// actions menu; selecting it expands the children and the label flips to
+// "Hide subagents". Leaf chats never show the toggle.
+export const SubagentsMenuToggle: Story = {
+	args: {
+		chats: [
+			buildChat({
+				id: "root-subagents",
+				title: "Parent with subagents",
+				workspace_id: "workspace-1",
+				updated_at: recentTimestamp,
+				children: [
+					buildChat({
+						id: "subagent-1",
+						title: "Subagent one",
+						parent_chat_id: "root-subagents",
+						root_chat_id: "root-subagents",
+					}),
+					buildChat({
+						id: "subagent-2",
+						title: "Subagent two",
+						parent_chat_id: "root-subagents",
+						root_chat_id: "root-subagents",
+					}),
+					buildChat({
+						id: "subagent-3",
+						title: "Subagent three",
+						parent_chat_id: "root-subagents",
+						root_chat_id: "root-subagents",
+					}),
+				],
+			}),
+		],
+	},
+	parameters: {
+		reactRouter: reactRouterParameters({
+			// Route to the parent (not a child) so the tree starts collapsed and
+			// the menu reads "Show subagents (3)".
+			location: {
+				path: "/agents/root-subagents",
+				pathParams: { agentId: "root-subagents" },
+			},
+			routing: agentsRouting,
+		}),
+	},
+	play: async ({ canvasElement }) => {
+		const canvas = within(canvasElement);
+		await waitFor(() => {
+			expect(canvas.getByText("Parent with subagents")).toBeInTheDocument();
+		});
+		// Collapsed by default: children are not rendered yet.
+		expect(canvas.queryByText("Subagent one")).not.toBeInTheDocument();
+
+		const trigger = canvas.getByLabelText(
+			"Open actions for Parent with subagents",
+		);
+		await userEvent.click(trigger);
+		const body = within(document.body);
+		await waitFor(() => {
+			expect(body.getByText("Show subagents (3)")).toBeInTheDocument();
+		});
+
+		// Selecting the toggle closes the menu and expands the children.
+		await userEvent.click(body.getByText("Show subagents (3)"));
+		await waitFor(() => {
+			expect(canvas.getByText("Subagent one")).toBeInTheDocument();
+		});
+
+		// Reopening the menu now offers the inverse action.
+		await userEvent.click(
+			canvas.getByLabelText("Open actions for Parent with subagents"),
+		);
+		await waitFor(() => {
+			expect(
+				within(document.body).getByText("Hide subagents"),
+			).toBeInTheDocument();
+		});
+	},
+};
+
 export const ArchivedChildChatRowHasNoActionsMenu: Story = {
 	args: {
 		chats: [
diff --git a/site/src/pages/AgentsPage/components/ChatsSidebar/tree/ChatTreeNode.tsx b/site/src/pages/AgentsPage/components/ChatsSidebar/tree/ChatTreeNode.tsx
index be0480ca49..04ed47cc7a 100644
--- a/site/src/pages/AgentsPage/components/ChatsSidebar/tree/ChatTreeNode.tsx
+++ b/site/src/pages/AgentsPage/components/ChatsSidebar/tree/ChatTreeNode.tsx
@@ -1,4 +1,5 @@
 import {
+	BotIcon,
 	ChevronDownIcon,
 	ChevronRightIcon,
 	EllipsisVerticalIcon,
@@ -150,6 +151,9 @@ export const ChatTreeNode: FC<ChatTreeNodeProps> = ({ chat, isChildNode }) => {
 		isChildChat: isChildNode,
 		hasWorkspace: Boolean(workspaceId),
 		isArchiving,
+		subagentCount: childIDs.length,
+		isSubagentsExpanded: isExpanded,
+		onToggleSubagents: () => toggleExpanded(chatID),
 		onPinAgent: () => onPinAgent(chat.id),
 		onUnpinAgent: () => onUnpinAgent(chat.id),
 		onArchiveAgent: () => onArchiveAgent(chat.id),
@@ -174,8 +178,6 @@ export const ChatTreeNode: FC<ChatTreeNodeProps> = ({ chat, isChildNode }) => {
 							"group relative flex min-w-0 select-none [@media(pointer:coarse)]:[-webkit-touch-callout:none] items-start gap-1.5 rounded-md pl-1 pr-1.5 text-content-secondary",
 							"transition-none [@media(hover:hover)]:hover:bg-surface-tertiary/50 [@media(hover:hover)]:hover:text-content-primary has-[[data-state=open]]:bg-surface-tertiary",
 							"has-[[aria-current=page]]:bg-surface-quaternary/25 has-[[aria-current=page]]:text-content-primary [@media(hover:hover)]:has-[[aria-current=page]]:hover:bg-surface-quaternary/50",
-							isChildNode &&
-								"before:absolute before:-left-2.5 before:top-[17px] before:h-px before:w-2.5 before:bg-border-default/70",
 						)}
 					>
 						<div
@@ -240,6 +242,17 @@ export const ChatTreeNode: FC<ChatTreeNodeProps> = ({ chat, isChildNode }) => {
 										)}
 									</div>
 									<div className="flex min-w-0 items-center gap-1.5">
+										{hasChildren && (
+											<span
+												className="inline-flex shrink-0 items-center gap-0.5 text-[13px] leading-4 tabular-nums text-content-secondary"
+												title={`${childIDs.length} ${
+													childIDs.length === 1 ? "subagent" : "subagents"
+												}`}
+											>
+												{childIDs.length}
+												<BotIcon className="size-3.5" aria-hidden="true" />
+											</span>
+										)}
 										{hasLinkedDiffStatus && hasLineStats && (
 											<span
 												className="inline-flex shrink-0 items-center gap-0.5 text-[13px] leading-4 tabular-nums"
@@ -349,7 +362,7 @@ export const ChatTreeNode: FC<ChatTreeNodeProps> = ({ chat, isChildNode }) => {
 			</ContextMenu>
 
 			{hasChildren && isExpanded && (
-				<div className="relative ml-4 flex flex-col border-l border-border-default/60 pl-2.5">
+				<div className="relative ml-4 flex flex-col pl-2.5">
 					{childIDs.map((childID) => {
 						const childChat = chatById.get(childID);
 						if (!childChat) return null;