From 62ce16d08f03f6ccc8f031c9b8a1b30f75ef98cc Mon Sep 17 00:00:00 2001
From: Ethan Dickson <ethan@coder.com>
Date: Tue, 18 Aug 2026 05:09:31 +0000
Subject: [PATCH] fix(site/src/pages/AgentsPage): persist empty MCP selection

---
 .../AgentsPage/AgentChatPage.stories.tsx      | 55 ++++++++++++++++++-
 site/src/pages/AgentsPage/AgentChatPage.tsx   |  5 +-
 2 files changed, 54 insertions(+), 6 deletions(-)

diff --git a/site/src/pages/AgentsPage/AgentChatPage.stories.tsx b/site/src/pages/AgentsPage/AgentChatPage.stories.tsx
index cc6b3784b62df..d124f03114e8e 100644
--- a/site/src/pages/AgentsPage/AgentChatPage.stories.tsx
+++ b/site/src/pages/AgentsPage/AgentChatPage.stories.tsx
@@ -26,6 +26,7 @@ import {
 	MockChat,
 	MockChatMessage,
 	MockChatQueuedMessage,
+	MockMCPServerConfig,
 } from "#/testHelpers/chatEntities";
 import { MockChatModelConfig } from "#/testHelpers/chatModels";
 import {
@@ -255,7 +256,10 @@ const buildChatAuthorizationQuery = (
 const buildQueries = (
 	chat: TypesGen.Chat,
 	messagesData: TypesGen.ChatMessagesResponse,
-	opts?: { diffUrl?: string },
+	opts?: {
+		diffUrl?: string;
+		mcpServers?: readonly TypesGen.MCPServerConfig[];
+	},
 ) => {
 	const diffStatus: TypesGen.ChatDiffStatus = {
 		chat_id: CHAT_ID,
@@ -301,7 +305,7 @@ const buildQueries = (
 		},
 		{ key: chatModelsKey, data: mockModelCatalog },
 		{ key: chatModelConfigs().queryKey, data: mockModelConfigs },
-		{ key: mcpServersKey, data: [] },
+		{ key: mcpServersKey, data: opts?.mcpServers ?? [] },
 		buildChatAuthorizationQuery(chat, {
 			canShareChat: {
 				action: "share",
@@ -3217,6 +3221,53 @@ export const SendResponseAfterChatSwitch: Story = {
 	},
 };
 
+export const RemoveLastMCPServer: Story = {
+	parameters: {
+		queries: buildQueries(
+			{
+				id: CHAT_ID,
+				...baseChatFields,
+				title: "Remove last MCP server",
+				status: "waiting",
+				mcp_server_ids: [MockMCPServerConfig.id],
+			},
+			{ messages: [], queued_messages: [], has_more: false },
+			{
+				diffUrl: undefined,
+				mcpServers: [MockMCPServerConfig],
+			},
+		),
+	},
+	beforeEach: () => {
+		spyOn(API.experimental, "getUserSkills").mockResolvedValue([]);
+	},
+	play: async ({ canvasElement }) => {
+		const canvas = within(canvasElement);
+		const sendSpy = spyOn(
+			API.experimental,
+			"createChatMessage",
+		).mockResolvedValue({ queued: false });
+
+		await userEvent.click(
+			await canvas.findByRole("button", { name: "Remove MCP Server" }),
+		);
+		const editor = await canvas.findByTestId("chat-message-input");
+		await userEvent.click(editor);
+		await userEvent.type(editor, "Send without MCP tools");
+		await userEvent.keyboard("{Enter}");
+
+		await waitFor(() => {
+			expect(sendSpy).toHaveBeenCalledTimes(1);
+		});
+		expect(sendSpy).toHaveBeenCalledWith(
+			CHAT_ID,
+			expect.objectContaining({
+				mcp_server_ids: [],
+			}),
+		);
+	},
+};
+
 /**
  * The send flow renders the durable user row once the server accepts the
  * prompt, before the assistant turn produces any output.
diff --git a/site/src/pages/AgentsPage/AgentChatPage.tsx b/site/src/pages/AgentsPage/AgentChatPage.tsx
index da472f7d646b4..efe81b3a18504 100644
--- a/site/src/pages/AgentsPage/AgentChatPage.tsx
+++ b/site/src/pages/AgentsPage/AgentChatPage.tsx
@@ -1799,10 +1799,7 @@ const AgentChatPage: FC = () => {
 			content,
 			model_config_id: selectedModelConfigID,
 			reasoning_effort: effectiveReasoningEffort,
-			mcp_server_ids:
-				effectiveMCPServerIds.length > 0
-					? [...effectiveMCPServerIds]
-					: undefined,
+			mcp_server_ids: [...effectiveMCPServerIds],
 			...(planModeSwitch !== undefined
 				? {
 						plan_mode: