fix(site/src/pages/AgentsPage/components/ChatConversation): remove attachment copy actions (#25119)

Messages with chat file attachments showed a `Copy message` action even
though the action only copied `parsed.markdown` and omitted the
attachment content.

Hide the message copy action whenever a parsed message contains file
attachments, and add regression coverage for both user and assistant
attachment messages.

Refs
https://linear.app/codercom/issue/CODAGT-344/remove-or-fix-copy-buttons-on-file-attachments

Generated by Coder Agents.

site/src/pages/AgentsPage/components/ChatConversation/ConversationTimeline.stories.tsx

@@ -252,6 +252,20 @@ const findAttachmentTile = async (
 	return tile;
 };
 
+const expectNoCopyMessageButtonForElement = (element: HTMLElement) => {
+	const messageRow = element.closest(
+		'[data-role="user"], [data-role="assistant"]',
+	);
+	expect(messageRow).not.toBeNull();
+	const messageWrapper = messageRow?.parentElement;
+	expect(messageWrapper).not.toBeNull();
+	expect(
+		within(messageWrapper as HTMLElement).queryByRole("button", {
+			name: "Copy message",
+		}),
+	).not.toBeInTheDocument();
+};
+
 const hoverAndExpectTooltip = async (
 	element: HTMLElement,
 	text: RegExp | string,
@@ -366,6 +380,7 @@ export const UserMessageWithSingleImage: Story = {
 		const canvas = within(canvasElement);
 		const images = canvas.getAllByRole("img", { name: "Attached image" });
 		expect(images).toHaveLength(1);
+		expectNoCopyMessageButtonForElement(images[0]);
 	},
 };
 
@@ -403,6 +418,7 @@ export const UserMessageWithMultipleImages: Story = {
 		const canvas = within(canvasElement);
 		const images = canvas.getAllByRole("img", { name: "Attached image" });
 		expect(images).toHaveLength(3);
+		expectNoCopyMessageButtonForElement(images[0]);
 	},
 };
 
@@ -423,6 +439,7 @@ export const UserMessageWithFileIdImage: Story = {
 			"src",
 			getChatFileURL("storybook-test-image"),
 		);
+		expectNoCopyMessageButtonForElement(images[0]);
 	},
 };
 
@@ -443,6 +460,7 @@ export const UserMessageWithExpiredImage: Story = {
 		expect(
 			canvas.queryByRole("button", { name: "View Attached image" }),
 		).not.toBeInTheDocument();
+		expectNoCopyMessageButtonForElement(expiredTile);
 
 		// The tooltip explains the retention policy generically so the
 		// copy survives any operator-chosen retention window.
@@ -482,6 +500,9 @@ export const UserMessageWithRepeatedExpiredImage: Story = {
 		expect(
 			canvas.queryByRole("button", { name: "View Attached image" }),
 		).not.toBeInTheDocument();
+		for (const tile of canvas.getAllByRole("img", { name: "Image expired" })) {
+			expectNoCopyMessageButtonForElement(tile);
+		}
 	},
 };
 
@@ -523,6 +544,7 @@ export const UserMessageWithRepeatedFailedImage: Story = {
 			return t;
 		});
 		for (const tile of tiles) {
+			expectNoCopyMessageButtonForElement(tile);
 			await hoverAndExpectTooltip(tile, FAILED_ATTACHMENT_API_MESSAGE);
 		}
 	},
@@ -540,11 +562,12 @@ export const UserMessageWithFailedRemoteImage: Story = {
 		const canvas = within(canvasElement);
 		const image = canvas.getByRole("img", { name: "Attached image" });
 		fireEvent.error(image);
-		await findAttachmentTile(canvas, "Image failed to load");
+		const failedTile = await findAttachmentTile(canvas, "Image failed to load");
 		expect(canvas.getByText("This image failed to load")).toBeInTheDocument();
 		expect(
 			canvas.queryByRole("button", { name: "View Attached image" }),
 		).not.toBeInTheDocument();
+		expectNoCopyMessageButtonForElement(failedTile);
 
 		// When the probe returns a structured error body, the tooltip
 		// surfaces the API's message so the viewer has something
@@ -572,7 +595,8 @@ export const UserMessageWithUndisplayableRemoteImage: Story = {
 		const canvas = within(canvasElement);
 		const image = canvas.getByRole("img", { name: "Attached image" });
 		fireEvent.error(image);
-		await findAttachmentTile(canvas, "Image failed to load");
+		const failedTile = await findAttachmentTile(canvas, "Image failed to load");
+		expectNoCopyMessageButtonForElement(failedTile);
 		await hoverAndExpectTooltip(
 			await waitForTooltipWrappedAttachmentTile(canvas, "Image failed to load"),
 			UNDISPLAYABLE_REMOTE_ATTACHMENT_MESSAGE,
@@ -592,13 +616,14 @@ export const UserMessageWithInvalidInlineImage: Story = {
 		const canvas = within(canvasElement);
 		const image = canvas.getByRole("img", { name: "Attached image" });
 		fireEvent.error(image);
-		await findAttachmentTile(canvas, "Image failed to load");
+		const failedTile = await findAttachmentTile(canvas, "Image failed to load");
 		expect(
 			canvas.getByText("Inline image data is corrupt"),
 		).toBeInTheDocument();
 		expect(
 			canvas.queryByRole("button", { name: "View Attached image" }),
 		).not.toBeInTheDocument();
+		expectNoCopyMessageButtonForElement(failedTile);
 	},
 };
 
@@ -616,6 +641,9 @@ export const UserMessageWithTextAttachment: Story = {
 		});
 		expect(textButton).toBeInTheDocument();
 		expect(textButton).toHaveTextContent(/Pasted text/i);
+		expect(
+			canvas.queryByRole("button", { name: "Copy message" }),
+		).not.toBeInTheDocument();
 		await userEvent.click(textButton);
 		expect(
 			await canvas.findByText(/Quarterly revenue increased 18%/i),
@@ -649,6 +677,9 @@ export const UserMessageWithJSONAttachment: Story = {
 			name: "View report.json",
 		});
 		expect(textButton).toHaveTextContent("report.json");
+		expect(
+			canvas.queryByRole("button", { name: "Copy message" }),
+		).not.toBeInTheDocument();
 		await userEvent.click(textButton);
 		expect(await canvas.findByText(/"status":"ok"/i)).toBeInTheDocument();
 	},
@@ -684,6 +715,9 @@ export const UserMessageWithDownloadableFile: Story = {
 			"/api/experimental/chats/files/storybook-user-deployment-report",
 		);
 		expect(canvas.getByText("deployment-report.pdf")).toBeInTheDocument();
+		expect(
+			canvas.queryByRole("button", { name: "Copy message" }),
+		).not.toBeInTheDocument();
 	},
 };
 
@@ -705,6 +739,7 @@ export const UserMessageWithMultipleTextAttachments: Story = {
 			name: "View text attachment",
 		});
 		expect(textButtons).toHaveLength(3);
+		expectNoCopyMessageButtonForElement(textButtons[0]);
 	},
 };
 
@@ -720,6 +755,7 @@ export const UserMessageWithTextAttachmentOnly: Story = {
 			name: "View text attachment",
 		});
 		expect(textButton).toHaveTextContent(/Pasted text/i);
+		expectNoCopyMessageButtonForElement(textButton);
 		await userEvent.click(textButton);
 		expect(
 			await canvas.findByText(/Runbook note: restart the worker/i),
@@ -739,6 +775,7 @@ export const UserMessageWithExpiredTextAttachment: Story = {
 		const textButton = await canvas.findByRole("button", {
 			name: "View text attachment",
 		});
+		expectNoCopyMessageButtonForElement(textButton);
 		await userEvent.click(textButton);
 		const expiredTile = await findAttachmentTile(canvas, "Attachment expired");
 		expect(
@@ -767,6 +804,7 @@ export const UserMessageWithFailedTextAttachment: Story = {
 		const textButton = await canvas.findByRole("button", {
 			name: "View text attachment",
 		});
+		expectNoCopyMessageButtonForElement(textButton);
 		await userEvent.click(textButton);
 		await findAttachmentTile(canvas, "Attachment failed to load");
 		expect(
@@ -813,6 +851,7 @@ export const UserMessageWithInlineTextAttachment: Story = {
 			name: "View text attachment",
 		});
 		expect(textButton).toHaveTextContent(/Pasted text/i);
+		expectNoCopyMessageButtonForElement(textButton);
 		await userEvent.click(textButton);
 		expect(
 			await canvas.findByText(/Inline deployment note/i),
@@ -850,6 +889,7 @@ export const UserMessageWithFailedTextAttachmentNonJSONBody: Story = {
 		const textButton = await canvas.findByRole("button", {
 			name: "View preview.txt",
 		});
+		expectNoCopyMessageButtonForElement(textButton);
 		await userEvent.click(textButton);
 		await findAttachmentTile(canvas, "Attachment failed to load");
 		expect(
@@ -878,6 +918,7 @@ export const UserMessageWithMixedAttachments: Story = {
 			name: "View text attachment",
 		});
 		expect(textButtons).toHaveLength(1);
+		expectNoCopyMessageButtonForElement(images[0]);
 	},
 };
 
@@ -934,6 +975,9 @@ export const AssistantMessageWithImage: Story = {
 		expect(
 			canvas.queryByRole("link", { name: "Download generated-image.png" }),
 		).not.toBeInTheDocument();
+		expect(
+			canvas.queryByRole("button", { name: "Copy message" }),
+		).not.toBeInTheDocument();
 		const viewButton = canvas.getByRole("button", {
 			name: "View generated-image.png",
 		});
@@ -974,6 +1018,9 @@ export const AssistantMessageWithUnnamedDownloadableFile: Story = {
 		expect(downloadLink).toBeInTheDocument();
 		expect(downloadLink).toHaveAttribute("download", "attachment.pdf");
 		expect(canvas.getByText("Attached file")).toBeInTheDocument();
+		expect(
+			canvas.queryByRole("button", { name: "Copy message" }),
+		).not.toBeInTheDocument();
 	},
 };
 
@@ -1009,6 +1056,7 @@ export const UserMessageWithImagesAndFileRefs: Story = {
 		const images = canvas.getAllByRole("img", { name: "Attached image" });
 		expect(images).toHaveLength(1);
 		expect(canvas.getByText(/main\.go/)).toBeInTheDocument();
+		expectNoCopyMessageButtonForElement(images[0]);
 	},
 };
 

site/src/pages/AgentsPage/components/ChatConversation/messageHelpers.test.ts

@@ -0,0 +1,60 @@
+import { describe, expect, it } from "vitest";
+import type { ChatMessage, ChatMessagePart } from "#/api/typesGenerated";
+import { deriveMessageDisplayState } from "./messageHelpers";
+import { parseMessageContent } from "./messageParsing";
+
+const buildMessage = (
+	content: ChatMessagePart[],
+	role: "user" | "assistant" = "user",
+): ChatMessage => ({
+	id: 1,
+	chat_id: "chat-1",
+	created_at: "2026-05-11T00:00:00.000Z",
+	role,
+	content,
+});
+
+const getDisplayState = (message: ChatMessage) =>
+	deriveMessageDisplayState({
+		message,
+		parsed: parseMessageContent(message.content),
+		hideActions: false,
+	});
+
+describe("deriveMessageDisplayState", () => {
+	it("marks text-only user messages as copyable", () => {
+		const message = buildMessage([{ type: "text", text: "Copy this" }]);
+
+		expect(getDisplayState(message).hasCopyableContent).toBe(true);
+	});
+
+	it("marks text-only assistant messages as copyable", () => {
+		const message = buildMessage(
+			[{ type: "text", text: "Here is my answer." }],
+			"assistant",
+		);
+
+		expect(getDisplayState(message).hasCopyableContent).toBe(true);
+	});
+
+	it("does not mark user messages with file attachments as copyable", () => {
+		const message = buildMessage([
+			{ type: "text", text: "Copy should not omit this file." },
+			{ type: "file", media_type: "text/plain", file_id: "file-1" },
+		]);
+
+		expect(getDisplayState(message).hasCopyableContent).toBe(false);
+	});
+
+	it("does not mark assistant messages with file attachments as copyable", () => {
+		const message = buildMessage(
+			[
+				{ type: "text", text: "Generated file attached." },
+				{ type: "file", media_type: "image/png", file_id: "image-1" },
+			],
+			"assistant",
+		);
+
+		expect(getDisplayState(message).hasCopyableContent).toBe(false);
+	});
+});

site/src/pages/AgentsPage/components/ChatConversation/messageHelpers.ts

@@ -5,12 +5,12 @@ export type UserInlineRenderBlock =
 	| Extract<RenderBlock, { type: "response" }>
 	| Extract<RenderBlock, { type: "file-reference" }>;
 
-type UserFileRenderBlock = Extract<RenderBlock, { type: "file" }>;
+type FileRenderBlock = Extract<RenderBlock, { type: "file" }>;
 
 export type MessageDisplayState = {
 	shouldHide: boolean;
 	userInlineContent: UserInlineRenderBlock[];
-	userFileBlocks: UserFileRenderBlock[];
+	userFileBlocks: FileRenderBlock[];
 	hasUserMessageBody: boolean;
 	hasFileBlocks: boolean;
 	hasCopyableContent: boolean;
@@ -22,9 +22,8 @@ const isUserInlineRenderBlock = (
 ): block is UserInlineRenderBlock =>
 	block.type === "response" || block.type === "file-reference";
 
-const isUserFileRenderBlock = (
-	block: RenderBlock,
-): block is UserFileRenderBlock => block.type === "file";
+const isFileRenderBlock = (block: RenderBlock): block is FileRenderBlock =>
+	block.type === "file";
 
 const isProviderToolResultOnlyMessage = (
 	parts: readonly TypesGen.ChatMessagePart[],
@@ -53,13 +52,13 @@ export const deriveMessageDisplayState = ({
 	const userInlineContent = isUser
 		? parsed.blocks.filter(isUserInlineRenderBlock)
 		: [];
-	const userFileBlocks = isUser
-		? parsed.blocks.filter(isUserFileRenderBlock)
-		: [];
+	const userFileBlocks = isUser ? parsed.blocks.filter(isFileRenderBlock) : [];
+	const hasFileAttachments = parsed.blocks.some(isFileRenderBlock);
 	const hasUserMessageBody =
 		userInlineContent.length > 0 || Boolean(parsed.markdown.trim());
 	const hasFileBlocks = userFileBlocks.length > 0;
-	const hasCopyableContent = Boolean(parsed.markdown.trim());
+	const hasCopyableContent =
+		Boolean(parsed.markdown.trim()) && !hasFileAttachments;
 	const hasRenderableContent =
 		parsed.blocks.length > 0 ||
 		parsed.tools.length > 0 ||