diff --git a/packages/ui/src/components/message-section.tsx b/packages/ui/src/components/message-section.tsx
index 283e4b24..19f611fd 100644
--- a/packages/ui/src/components/message-section.tsx
+++ b/packages/ui/src/components/message-section.tsx
@@ -7,6 +7,8 @@ import { getSessionInfo } from "../stores/sessions"
 import { messageStoreBus } from "../stores/message-v2/bus"
 import { useScrollCache } from "../lib/hooks/use-scroll-cache"
 import { useI18n } from "../lib/i18n"
+import { copyToClipboard } from "../lib/clipboard"
+import { showToastNotification } from "../lib/notifications"
 import type { InstanceMessageStore } from "../stores/message-v2/instance-store"
 
 const SCROLL_SCOPE = "session"
@@ -375,7 +377,9 @@ export default function MessageSection(props: MessageSectionProps) {
     const anchorRect = rects.length > 0 ? rects[0] : range.getBoundingClientRect()
     const shellRect = shell.getBoundingClientRect()
     const relativeTop = Math.max(anchorRect.top - shellRect.top - 40, 8)
-    const maxLeft = Math.max(shell.clientWidth - 180, 8)
+    // Keep the popover within the stream shell. The quote popover currently
+    // renders 3 actions; keep enough horizontal room for the pill.
+    const maxLeft = Math.max(shell.clientWidth - 260, 8)
     const relativeLeft = Math.min(Math.max(anchorRect.left - shellRect.left, 8), maxLeft)
     setQuoteSelection({ text: limited, top: relativeTop, left: relativeLeft })
   }
@@ -394,6 +398,24 @@ export default function MessageSection(props: MessageSectionProps) {
       selection?.removeAllRanges()
     }
   }
+
+  async function handleCopySelectionRequest() {
+    const info = quoteSelection()
+    if (!info) return
+
+    const success = await copyToClipboard(info.text)
+    showToastNotification({
+      message: success ? t("messageSection.quote.copied") : t("messageSection.quote.copyFailed"),
+      variant: success ? "success" : "error",
+      duration: success ? 2000 : 6000,
+    })
+
+    clearQuoteSelection()
+    if (typeof window !== "undefined") {
+      const selection = window.getSelection()
+      selection?.removeAllRanges()
+    }
+  }
  
   function handleContentRendered() {
     if (props.loading) {
@@ -835,6 +857,9 @@ export default function MessageSection(props: MessageSectionProps) {
                   <button type="button" class="message-quote-button" onClick={() => handleQuoteSelectionRequest("code")}>
                     {t("messageSection.quote.addAsCode")}
                   </button>
+                  <button type="button" class="message-quote-button" onClick={() => void handleCopySelectionRequest()}>
+                    {t("messageSection.quote.copy")}
+                  </button>
                 </div>
               </div>
             )}
diff --git a/packages/ui/src/lib/i18n/messages/en/messaging.ts b/packages/ui/src/lib/i18n/messages/en/messaging.ts
index b2c8568a..61783e6f 100644
--- a/packages/ui/src/lib/i18n/messages/en/messaging.ts
+++ b/packages/ui/src/lib/i18n/messages/en/messaging.ts
@@ -20,6 +20,9 @@ export const messagingMessages = {
   "messageSection.scroll.toLatestAriaLabel": "Scroll to latest message",
   "messageSection.quote.addAsQuote": "Add as quote",
   "messageSection.quote.addAsCode": "Add as code",
+  "messageSection.quote.copy": "Copy",
+  "messageSection.quote.copied": "Copied!",
+  "messageSection.quote.copyFailed": "Copy failed",
 
   "messageTimeline.ariaLabel": "Message timeline",
   "messageTimeline.segment.user.label": "You",
diff --git a/packages/ui/src/lib/i18n/messages/es/messaging.ts b/packages/ui/src/lib/i18n/messages/es/messaging.ts
index 1c1da653..dd10f351 100644
--- a/packages/ui/src/lib/i18n/messages/es/messaging.ts
+++ b/packages/ui/src/lib/i18n/messages/es/messaging.ts
@@ -20,6 +20,9 @@ export const messagingMessages = {
   "messageSection.scroll.toLatestAriaLabel": "Desplazarse al último mensaje",
   "messageSection.quote.addAsQuote": "Añadir como cita",
   "messageSection.quote.addAsCode": "Añadir como código",
+  "messageSection.quote.copy": "Copiar",
+  "messageSection.quote.copied": "¡Copiado!",
+  "messageSection.quote.copyFailed": "No se pudo copiar",
 
   "messageTimeline.ariaLabel": "Línea de tiempo de mensajes",
   "messageTimeline.segment.user.label": "Tú",
diff --git a/packages/ui/src/lib/i18n/messages/fr/messaging.ts b/packages/ui/src/lib/i18n/messages/fr/messaging.ts
index ef8fecf1..6bb886ae 100644
--- a/packages/ui/src/lib/i18n/messages/fr/messaging.ts
+++ b/packages/ui/src/lib/i18n/messages/fr/messaging.ts
@@ -20,6 +20,9 @@ export const messagingMessages = {
   "messageSection.scroll.toLatestAriaLabel": "Aller au dernier message",
   "messageSection.quote.addAsQuote": "Ajouter en citation",
   "messageSection.quote.addAsCode": "Ajouter en code",
+  "messageSection.quote.copy": "Copier",
+  "messageSection.quote.copied": "Copié !",
+  "messageSection.quote.copyFailed": "Impossible de copier",
 
   "messageTimeline.ariaLabel": "Chronologie des messages",
   "messageTimeline.segment.user.label": "Vous",
diff --git a/packages/ui/src/lib/i18n/messages/ja/messaging.ts b/packages/ui/src/lib/i18n/messages/ja/messaging.ts
index 25823eb9..456d9f4b 100644
--- a/packages/ui/src/lib/i18n/messages/ja/messaging.ts
+++ b/packages/ui/src/lib/i18n/messages/ja/messaging.ts
@@ -20,6 +20,9 @@ export const messagingMessages = {
   "messageSection.scroll.toLatestAriaLabel": "最新のメッセージへスクロール",
   "messageSection.quote.addAsQuote": "引用として追加",
   "messageSection.quote.addAsCode": "コードとして追加",
+  "messageSection.quote.copy": "コピー",
+  "messageSection.quote.copied": "コピーしました",
+  "messageSection.quote.copyFailed": "コピーできませんでした",
 
   "messageTimeline.ariaLabel": "メッセージタイムライン",
   "messageTimeline.segment.user.label": "あなた",
diff --git a/packages/ui/src/lib/i18n/messages/ru/messaging.ts b/packages/ui/src/lib/i18n/messages/ru/messaging.ts
index 3fe9e15d..4021c18b 100644
--- a/packages/ui/src/lib/i18n/messages/ru/messaging.ts
+++ b/packages/ui/src/lib/i18n/messages/ru/messaging.ts
@@ -20,6 +20,9 @@ export const messagingMessages = {
   "messageSection.scroll.toLatestAriaLabel": "Прокрутить к последнему сообщению",
   "messageSection.quote.addAsQuote": "Добавить как цитату",
   "messageSection.quote.addAsCode": "Добавить как код",
+  "messageSection.quote.copy": "Копировать",
+  "messageSection.quote.copied": "Скопировано!",
+  "messageSection.quote.copyFailed": "Не удалось скопировать",
 
   "messageTimeline.ariaLabel": "Таймлайн сообщений",
   "messageTimeline.segment.user.label": "Вы",
diff --git a/packages/ui/src/lib/i18n/messages/zh-Hans/messaging.ts b/packages/ui/src/lib/i18n/messages/zh-Hans/messaging.ts
index 93f7a15d..e8a252af 100644
--- a/packages/ui/src/lib/i18n/messages/zh-Hans/messaging.ts
+++ b/packages/ui/src/lib/i18n/messages/zh-Hans/messaging.ts
@@ -20,6 +20,9 @@ export const messagingMessages = {
   "messageSection.scroll.toLatestAriaLabel": "滚动到最新消息",
   "messageSection.quote.addAsQuote": "作为引用添加",
   "messageSection.quote.addAsCode": "作为代码添加",
+  "messageSection.quote.copy": "复制",
+  "messageSection.quote.copied": "已复制！",
+  "messageSection.quote.copyFailed": "无法复制",
 
   "messageTimeline.ariaLabel": "消息时间线",
   "messageTimeline.segment.user.label": "你",