From bbeff0d4b5e0c35106dc8760ef195cb537961fbb Mon Sep 17 00:00:00 2001
From: Mathias Fredriksson <mafredri@gmail.com>
Date: Thu, 2 Apr 2026 11:58:00 +0300
Subject: [PATCH] fix(site/src/pages/AgentsPage): hide copy button during
 active turn (#23962)

The copy button on the last assistant message was showing even while the
turn was still in progress (agent streaming or running tool calls). The
content is not final at that point, so the button should be suppressed
until the turn completes.

The `lastAssistantPerTurnIds` computation unconditionally included the
trailing assistant message. Now it checks a new `isTurnActive` prop
derived from `isActiveChatStatus(chatStatus) || hasStreamState` and
skips the trailing ID when the turn is active. Completed turns (those
followed by a user message) are unaffected.
---
 .../ConversationTimeline.stories.tsx          | 33 +++++++++++++++++++
 .../ChatConversation/ConversationTimeline.tsx | 10 +++++-
 .../AgentsPage/components/ChatPageContent.tsx |  5 +++
 3 files changed, 47 insertions(+), 1 deletion(-)

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}