diff --git a/site/src/pages/AgentsPage/components/ChatConversation/ConversationTimeline.stories.tsx b/site/src/pages/AgentsPage/components/ChatConversation/ConversationTimeline.stories.tsx
index aa8df60931..458418ba31 100644
--- a/site/src/pages/AgentsPage/components/ChatConversation/ConversationTimeline.stories.tsx
+++ b/site/src/pages/AgentsPage/components/ChatConversation/ConversationTimeline.stories.tsx
@@ -64,6 +64,7 @@ const defaultArgs: Omit<
 	"parsedMessages"
 > = {
 	subagentTitles: new Map(),
+	isTurnActive: false,
 };
 
 const meta: Meta<typeof ConversationTimeline> = {
@@ -766,6 +767,38 @@ export const CopyButtonWritesToClipboard: Story = {
 	},
 };
 
+/**
+ * When the turn is still active (isTurnActive=true), the trailing
+ * assistant message should NOT show a copy button because the
+ * content is not yet final.
+ */
+export const NoCopyButtonDuringActiveTurn: Story = {
+	args: {
+		...defaultArgs,
+		isTurnActive: true,
+		parsedMessages: buildMessages([
+			{
+				...baseMessage,
+				id: 1,
+				role: "user",
+				content: [{ type: "text", text: "Fix the bug" }],
+			},
+			{
+				...baseMessage,
+				id: 2,
+				role: "assistant",
+				content: [{ type: "text", text: "Let me look at the code." }],
+			},
+		]),
+	},
+	play: async ({ canvasElement }) => {
+		const canvas = within(canvasElement);
+		expect(
+			canvas.queryByTestId("assistant-copy-button"),
+		).not.toBeInTheDocument();
+	},
+};
+
 /**
  * Regression: copy button appears only on the last assistant message
  * in a turn that includes tool calls. The isLastAssistantMessage
diff --git a/site/src/pages/AgentsPage/components/ChatConversation/ConversationTimeline.tsx b/site/src/pages/AgentsPage/components/ChatConversation/ConversationTimeline.tsx
index f080e111a1..7caff5e8ed 100644
--- a/site/src/pages/AgentsPage/components/ChatConversation/ConversationTimeline.tsx
+++ b/site/src/pages/AgentsPage/components/ChatConversation/ConversationTimeline.tsx
@@ -1009,6 +1009,11 @@ interface ConversationTimelineProps {
 	mcpServers?: readonly TypesGen.MCPServerConfig[];
 	computerUseSubagentIds?: Set<string>;
 	showDesktopPreviews?: boolean;
+	// When true the current turn is still in progress (the agent
+	// is streaming or a tool call is running). The copy button on
+	// the trailing assistant message is suppressed because the
+	// content is not yet final.
+	isTurnActive: boolean;
 }
 
 export const ConversationTimeline = memo<ConversationTimelineProps>(
@@ -1022,6 +1027,7 @@ export const ConversationTimeline = memo<ConversationTimelineProps>(
 		mcpServers,
 		computerUseSubagentIds,
 		showDesktopPreviews,
+		isTurnActive,
 	}) => {
 		if (parsedMessages.length === 0) {
 			return null;
@@ -1055,7 +1061,9 @@ export const ConversationTimeline = memo<ConversationTimelineProps>(
 							lastAsstId = null;
 						}
 					}
-					if (lastAsstId != null) lastAssistantPerTurnIds.add(lastAsstId);
+					if (lastAsstId != null && !isTurnActive) {
+						lastAssistantPerTurnIds.add(lastAsstId);
+					}
 					return parsedMessages.map(({ message, parsed }) =>
 						message.role === "user" ? (
 							<StickyUserMessage
diff --git a/site/src/pages/AgentsPage/components/ChatPageContent.tsx b/site/src/pages/AgentsPage/components/ChatPageContent.tsx
index f3e945946f..0a9511cf55 100644
--- a/site/src/pages/AgentsPage/components/ChatPageContent.tsx
+++ b/site/src/pages/AgentsPage/components/ChatPageContent.tsx
@@ -13,6 +13,7 @@ import {
 import { ConversationTimeline } from "./ChatConversation/ConversationTimeline";
 import { getLatestContextUsage } from "./ChatConversation/chatHelpers";
 import {
+	isActiveChatStatus,
 	selectChatStatus,
 	selectHasStreamState,
 	selectMessagesByID,
@@ -64,6 +65,9 @@ export const ChatPageTimeline: FC<ChatPageTimelineProps> = ({
 }) => {
 	const messagesByID = useChatSelector(store, selectMessagesByID);
 	const orderedMessageIDs = useChatSelector(store, selectOrderedMessageIDs);
+	const chatStatus = useChatSelector(store, selectChatStatus);
+	const hasStreamState = useChatSelector(store, selectHasStreamState);
+	const isTurnActive = isActiveChatStatus(chatStatus) || hasStreamState;
 
 	const messages = orderedMessageIDs
 		.map((messageID) => messagesByID.get(messageID))
@@ -91,6 +95,7 @@ export const ChatPageTimeline: FC<ChatPageTimelineProps> = ({
 					mcpServers={mcpServers}
 					computerUseSubagentIds={computerUseSubagentIds}
 					showDesktopPreviews={false}
+					isTurnActive={isTurnActive}
 				/>
 				<LiveStreamTail
 					store={store}