From 543fb7c5635737852cbb380b317ce685a04d84de Mon Sep 17 00:00:00 2001
From: Rafael Soley <110256307+byrafael@users.noreply.github.com>
Date: Wed, 25 Mar 2026 18:13:03 -0600
Subject: [PATCH 1/2] Add copy button to assistant messages

- Show copy action for non-empty assistant text
- Keep empty responses uncopiable and covered by tests
---
 .../components/chat/MessagesTimeline.test.tsx | 137 ++++++++++++++++++
 .../src/components/chat/MessagesTimeline.tsx  |  26 ++--
 2 files changed, 153 insertions(+), 10 deletions(-)

diff --git a/apps/web/src/components/chat/MessagesTimeline.test.tsx b/apps/web/src/components/chat/MessagesTimeline.test.tsx
index 692438c74a..8877f0eb7c 100644
--- a/apps/web/src/components/chat/MessagesTimeline.test.tsx
+++ b/apps/web/src/components/chat/MessagesTimeline.test.tsx
@@ -140,4 +140,141 @@ describe("MessagesTimeline", () => {
     expect(markup).toContain("Context compacted");
     expect(markup).toContain("Work log");
   });
+
+  it("renders a copy button for assistant messages with text", async () => {
+    const { MessagesTimeline } = await import("./MessagesTimeline");
+    const markup = renderToStaticMarkup(
+      <MessagesTimeline
+        hasMessages
+        isWorking={false}
+        activeTurnInProgress={false}
+        activeTurnStartedAt={null}
+        scrollContainer={null}
+        timelineEntries={[
+          {
+            id: "entry-1",
+            kind: "message",
+            createdAt: "2026-03-17T19:12:28.000Z",
+            message: {
+              id: MessageId.makeUnsafe("message-assistant-1"),
+              role: "assistant",
+              text: "Here is the agent response.",
+              createdAt: "2026-03-17T19:12:28.000Z",
+              completedAt: "2026-03-17T19:12:30.000Z",
+              streaming: false,
+            },
+          },
+        ]}
+        completionDividerBeforeEntryId={null}
+        completionSummary={null}
+        turnDiffSummaryByAssistantMessageId={new Map()}
+        nowIso="2026-03-17T19:12:30.000Z"
+        expandedWorkGroups={{}}
+        onToggleWorkGroup={() => {}}
+        onOpenTurnDiff={() => {}}
+        revertTurnCountByUserMessageId={new Map()}
+        onRevertUserMessage={() => {}}
+        isRevertingCheckpoint={false}
+        onImageExpand={() => {}}
+        markdownCwd={undefined}
+        resolvedTheme="light"
+        timestampFormat="locale"
+        workspaceRoot={undefined}
+      />,
+    );
+
+    expect(markup).toContain("Here is the agent response.");
+    expect(markup).toContain('title="Copy message"');
+  });
+
+  it("does not render a copy button for empty non-streaming assistant messages", async () => {
+    const { MessagesTimeline } = await import("./MessagesTimeline");
+    const markup = renderToStaticMarkup(
+      <MessagesTimeline
+        hasMessages
+        isWorking={false}
+        activeTurnInProgress={false}
+        activeTurnStartedAt={null}
+        scrollContainer={null}
+        timelineEntries={[
+          {
+            id: "entry-1",
+            kind: "message",
+            createdAt: "2026-03-17T19:12:28.000Z",
+            message: {
+              id: MessageId.makeUnsafe("message-assistant-empty"),
+              role: "assistant",
+              text: "",
+              createdAt: "2026-03-17T19:12:28.000Z",
+              completedAt: "2026-03-17T19:12:30.000Z",
+              streaming: false,
+            },
+          },
+        ]}
+        completionDividerBeforeEntryId={null}
+        completionSummary={null}
+        turnDiffSummaryByAssistantMessageId={new Map()}
+        nowIso="2026-03-17T19:12:30.000Z"
+        expandedWorkGroups={{}}
+        onToggleWorkGroup={() => {}}
+        onOpenTurnDiff={() => {}}
+        revertTurnCountByUserMessageId={new Map()}
+        onRevertUserMessage={() => {}}
+        isRevertingCheckpoint={false}
+        onImageExpand={() => {}}
+        markdownCwd={undefined}
+        resolvedTheme="light"
+        timestampFormat="locale"
+        workspaceRoot={undefined}
+      />,
+    );
+
+    expect(markup).toContain("(empty response)");
+    expect(markup).not.toContain('title="Copy message"');
+  });
+
+  it("renders a copy button for streaming assistant messages with buffered text", async () => {
+    const { MessagesTimeline } = await import("./MessagesTimeline");
+    const markup = renderToStaticMarkup(
+      <MessagesTimeline
+        hasMessages
+        isWorking={false}
+        activeTurnInProgress={false}
+        activeTurnStartedAt={null}
+        scrollContainer={null}
+        timelineEntries={[
+          {
+            id: "entry-1",
+            kind: "message",
+            createdAt: "2026-03-17T19:12:28.000Z",
+            message: {
+              id: MessageId.makeUnsafe("message-assistant-streaming"),
+              role: "assistant",
+              text: "Partial streamed output",
+              createdAt: "2026-03-17T19:12:28.000Z",
+              streaming: true,
+            },
+          },
+        ]}
+        completionDividerBeforeEntryId={null}
+        completionSummary={null}
+        turnDiffSummaryByAssistantMessageId={new Map()}
+        nowIso="2026-03-17T19:12:30.000Z"
+        expandedWorkGroups={{}}
+        onToggleWorkGroup={() => {}}
+        onOpenTurnDiff={() => {}}
+        revertTurnCountByUserMessageId={new Map()}
+        onRevertUserMessage={() => {}}
+        isRevertingCheckpoint={false}
+        onImageExpand={() => {}}
+        markdownCwd={undefined}
+        resolvedTheme="light"
+        timestampFormat="locale"
+        workspaceRoot={undefined}
+      />,
+    );
+
+    expect(markup).toContain("Partial streamed output");
+    expect(markup).toContain('title="Copy message"');
+  });
 });
diff --git a/apps/web/src/components/chat/MessagesTimeline.tsx b/apps/web/src/components/chat/MessagesTimeline.tsx
index f3e462f7fe..cab1e192c1 100644
--- a/apps/web/src/components/chat/MessagesTimeline.tsx
+++ b/apps/web/src/components/chat/MessagesTimeline.tsx
@@ -437,6 +437,7 @@ export const MessagesTimeline = memo(function MessagesTimeline({
         row.message.role === "assistant" &&
         (() => {
           const messageText = row.message.text || (row.message.streaming ? "" : "(empty response)");
+          const canCopyMessage = row.message.text.trim().length > 0;
           return (
             <>
               {row.showCompletionDivider && (
@@ -448,7 +449,7 @@ export const MessagesTimeline = memo(function MessagesTimeline({
                   <span className="h-px flex-1 bg-border" />
                 </div>
               )}
-              <div className="min-w-0 px-1 py-0.5">
+              <div className="group min-w-0 px-1 py-0.5">
                 <ChatMarkdown
                   text={messageText}
                   cwd={markdownCwd}
@@ -510,15 +511,20 @@ export const MessagesTimeline = memo(function MessagesTimeline({
                     </div>
                   );
                 })()}
-                <p className="mt-1.5 text-[10px] text-muted-foreground/30">
-                  {formatMessageMeta(
-                    row.message.createdAt,
-                    row.message.streaming
-                      ? formatElapsed(row.durationStart, nowIso)
-                      : formatElapsed(row.durationStart, row.message.completedAt),
-                    timestampFormat,
-                  )}
-                </p>
+                <div className="mt-1.5 flex w-fit items-center gap-2">
+                  <p className="text-[10px] text-muted-foreground/30">
+                    {formatMessageMeta(
+                      row.message.createdAt,
+                      row.message.streaming
+                        ? formatElapsed(row.durationStart, nowIso)
+                        : formatElapsed(row.durationStart, row.message.completedAt),
+                      timestampFormat,
+                    )}
+                  </p>
+                  <div className="flex items-center gap-1.5 opacity-0 transition-opacity duration-200 focus-within:opacity-100 group-hover:opacity-100">
+                    {canCopyMessage && <MessageCopyButton text={row.message.text} />}
+                  </div>
+                </div>
               </div>
             </>
           );

From 36d0c0b8d25b7e7f5f9e326c96488f17c4ace9a4 Mon Sep 17 00:00:00 2001
From: Rafael Soley <110256307+byrafael@users.noreply.github.com>
Date: Wed, 25 Mar 2026 18:30:50 -0600
Subject: [PATCH 2/2] Show assistant copy button on message hover

- scope the assistant message group for hover state
- reveal the copy action only when hovering that message
---
 apps/web/src/components/chat/MessagesTimeline.tsx | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/apps/web/src/components/chat/MessagesTimeline.tsx b/apps/web/src/components/chat/MessagesTimeline.tsx
index cab1e192c1..7b13f4588f 100644
--- a/apps/web/src/components/chat/MessagesTimeline.tsx
+++ b/apps/web/src/components/chat/MessagesTimeline.tsx
@@ -449,7 +449,7 @@ export const MessagesTimeline = memo(function MessagesTimeline({
                   <span className="h-px flex-1 bg-border" />
                 </div>
               )}
-              <div className="group min-w-0 px-1 py-0.5">
+              <div className="group/assistant-message min-w-0 px-1 py-0.5">
                 <ChatMarkdown
                   text={messageText}
                   cwd={markdownCwd}
@@ -521,7 +521,7 @@ export const MessagesTimeline = memo(function MessagesTimeline({
                       timestampFormat,
                     )}
                   </p>
-                  <div className="flex items-center gap-1.5 opacity-0 transition-opacity duration-200 focus-within:opacity-100 group-hover:opacity-100">
+                  <div className="flex items-center gap-1.5 opacity-0 transition-opacity duration-200 focus-within:opacity-100 group-hover/assistant-message:opacity-100">
                     {canCopyMessage && <MessageCopyButton text={row.message.text} />}
                   </div>
                 </div>