diff --git a/packages/ui/src/components/chat/message/MessageBody.tsx b/packages/ui/src/components/chat/message/MessageBody.tsx
index 9def5286..3623d30e 100644
--- a/packages/ui/src/components/chat/message/MessageBody.tsx
+++ b/packages/ui/src/components/chat/message/MessageBody.tsx
@@ -489,6 +489,20 @@ const UserMessageBody = React.memo(({ messageId, parts, messageCreatedAt, isMobi
     const [copyHintVisible, setCopyHintVisible] = React.useState(false);
     const copyHintTimeoutRef = React.useRef<number | null>(null);
 
+    // One expanded state for the whole message: text parts and context cards
+    // collapse and expand together, with a single collapse control up here
+    // instead of one per part.
+    const collapsibleUserMessages = useUIStore((state) => state.collapsibleUserMessages);
+    const [messageExpanded, setMessageExpanded] = React.useState(false);
+    const expandMessage = React.useCallback(() => setMessageExpanded(true), []);
+    const collapseMessage = React.useCallback((event: React.MouseEvent) => {
+        event.stopPropagation();
+        setMessageExpanded(false);
+    }, []);
+    React.useEffect(() => {
+        if (!collapsibleUserMessages) setMessageExpanded(false);
+    }, [collapsibleUserMessages]);
+
     const userContentParts = React.useMemo(() => {
         return parts.filter((part) => {
             if (part.type === 'text') {
@@ -716,6 +730,16 @@ const UserMessageBody = React.memo(({ messageId, parts, messageCreatedAt, isMobi
             style={CONTAIN_LAYOUT_STYLE}
             onTouchStart={isTouchContext && canCopyMessage && hasCopyableText ? revealCopyHint : undefined}
         >
+            {collapsibleUserMessages && messageExpanded && (
+                <button
+                    type="button"
+                    onClick={collapseMessage}
+                    className="absolute top-0 right-0 z-10 flex items-center justify-center rounded-sm bg-[var(--surface-elevated)] p-0.5 text-[var(--surface-mutedForeground)] transition-colors hover:bg-[var(--interactive-hover)] hover:text-[var(--surface-foreground)]"
+                    aria-label={t('chat.message.userText.collapseAria')}
+                >
+                    <Icon name="arrow-up-s" className="h-3.5 w-3.5" />
+                </button>
+            )}
             <div
                 className={cn(
                     'leading-relaxed text-foreground/90 text-base overflow-x-hidden',
@@ -760,6 +784,8 @@ const UserMessageBody = React.memo(({ messageId, parts, messageCreatedAt, isMobi
                                 messageId={messageId}
                                 isMobile={isMobile}
                                 agentMention={mentionForPart}
+                                messageExpanded={messageExpanded}
+                                onExpandMessage={expandMessage}
                             />
                         </React.Fragment>
                     );
diff --git a/packages/ui/src/components/chat/message/parts/UserContextPart.tsx b/packages/ui/src/components/chat/message/parts/UserContextPart.tsx
index 3f1e2cac..4402b243 100644
--- a/packages/ui/src/components/chat/message/parts/UserContextPart.tsx
+++ b/packages/ui/src/components/chat/message/parts/UserContextPart.tsx
@@ -4,16 +4,17 @@ import { Icon } from '@/components/icon/Icon';
 import type { IconName } from '@/components/icon/icons';
 import { useI18n } from '@/lib/i18n';
 import type { ContextPartPayload } from '@/lib/messages/contextParts';
+import { cn } from '@/lib/utils';
 
 /**
  * A context item attached to a user message: an inline code comment, a
  * terminal selection, a browser annotation, or GitHub PR context.
  *
- * Each item renders as one card so the user's comment reads as part of the
- * annotation, not as more message text: a header naming the source (with an
- * expand affordance when captured code/output exists), and the comment text
- * below it inside the same card. A header with nothing to reveal renders
- * without the expand affordance.
+ * The quoted material renders as a messenger-style reply: a source caption and
+ * the quote behind a plain left bar, in muted text, clamped to a few lines
+ * (click toggles the full quote). The user's comment follows below as regular
+ * message text, so the pair reads as "a reply to this quote" instead of a
+ * boxed widget inside the bubble.
  */
 
 const ContextCard: React.FC<{
@@ -23,31 +24,69 @@ const ContextCard: React.FC<{
     title?: string;
     body: string;
     text: string;
-}> = ({ icon, summary, title, body, text }) => {
+    /** Render the quote in the code font (code, terminal output, CI logs). */
+    mono?: boolean;
+    /**
+     * Message-level collapse: with collapsible messages on, the whole user
+     * message (text parts and cards alike) shares one expanded state, so a
+     * collapsed card is a two-line preview and a click asks the message to
+     * expand instead of toggling anything of its own.
+     */
+    collapsed?: boolean;
+    onExpand?: () => void;
+}> = ({ icon, summary, title, body, text, mono, collapsed, onExpand }) => {
+    const [expanded, setExpanded] = React.useState(false);
     const hasBody = body.trim().length > 0;
     const hasText = text.trim().length > 0;
 
-    const header = hasBody ? (
-        <details className="min-w-0">
-            <summary className="flex cursor-pointer items-center gap-1.5 px-2.5 py-1.5 text-xs text-[var(--surface-mutedForeground)] hover:text-[var(--surface-foreground)] [&::-webkit-details-marker]:hidden" title={title}>
-                <Icon name="arrow-right-s" className="h-3.5 w-3.5 shrink-0 transition-transform [details[open]_&]:rotate-90" />
+    if (collapsed) {
+        // One line per attachment: the source caption, and the user's comment
+        // after it when there is one ("Quoted from an earlier message: thanks,
+        // that settles it"). Attachments without a comment (terminal output
+        // and the like) collapse to the caption alone.
+        const comment = text.trim();
+        return (
+            <div
+                className="my-1 flex min-w-0 max-w-full cursor-pointer items-center gap-1.5 border-l-2 border-[var(--interactive-border)] pl-3 text-xs text-[var(--surface-mutedForeground)]"
+                onClick={onExpand}
+                title={title}
+            >
                 <Icon name={icon} className="h-3.5 w-3.5 shrink-0" />
-                <span className="truncate">{summary}</span>
-            </summary>
-            <pre className="max-h-48 overflow-auto whitespace-pre-wrap border-t border-[var(--interactive-border)] bg-[var(--surface-background)] px-2.5 py-2 font-mono text-xs text-[var(--surface-foreground)]">{body}</pre>
-        </details>
-    ) : (
-        <div className="flex items-center gap-1.5 px-2.5 py-1.5 text-xs text-[var(--surface-mutedForeground)]" title={title}>
-            <Icon name={icon} className="h-3.5 w-3.5 shrink-0" />
-            <span className="truncate">{summary}</span>
-        </div>
-    );
+                <span className="truncate">
+                    {comment.length > 0 ? `${summary}: ` : summary}
+                    {comment.length > 0 ? (
+                        <span className="text-sm text-[var(--surface-foreground)]">{comment}</span>
+                    ) : null}
+                </span>
+            </div>
+        );
+    }
 
     return (
-        <div className="my-1 max-w-full overflow-hidden rounded-lg border border-[var(--interactive-border)] bg-[var(--surface-elevated)]">
-            {header}
+        <div className="my-1.5 min-w-0 max-w-full">
+            <div
+                className={cn('min-w-0 border-l-2 border-[var(--interactive-border)] pl-3', hasBody && 'cursor-pointer')}
+                onClick={hasBody ? () => setExpanded((value) => !value) : undefined}
+                title={title}
+            >
+                <div className="flex items-center gap-1.5 text-xs text-[var(--surface-mutedForeground)]">
+                    <Icon name={icon} className="h-3.5 w-3.5 shrink-0" />
+                    <span className="truncate">{summary}</span>
+                </div>
+                {hasBody ? (
+                    <div
+                        className={cn(
+                            'mt-1 whitespace-pre-wrap break-words text-[var(--surface-mutedForeground)]',
+                            mono ? 'font-mono text-xs leading-5' : 'text-sm',
+                            !expanded && 'line-clamp-4'
+                        )}
+                    >
+                        {body}
+                    </div>
+                ) : null}
+            </div>
             {hasText ? (
-                <div className="whitespace-pre-wrap break-words border-t border-[var(--interactive-border)] px-2.5 py-2 font-sans text-sm text-[var(--surface-foreground)]">{text}</div>
+                <div className="mt-1.5 whitespace-pre-wrap break-words font-sans text-sm text-[var(--surface-foreground)]">{text}</div>
             ) : null}
         </div>
     );
@@ -58,8 +97,14 @@ const basename = (path: string): string => {
     return segments[segments.length - 1] ?? path;
 };
 
-const UserContextPart: React.FC<{ payload: ContextPartPayload }> = ({ payload }) => {
+const UserContextPart: React.FC<{
+    payload: ContextPartPayload;
+    /** Message-level collapse state, shared with the text parts. */
+    collapsed?: boolean;
+    onExpand?: () => void;
+}> = ({ payload, collapsed, onExpand }) => {
     const { t } = useI18n();
+    const shared = { collapsed, onExpand };
 
     switch (payload.kind) {
         case 'code-comment': {
@@ -70,7 +115,7 @@ const UserContextPart: React.FC<{ payload: ContextPartPayload }> = ({ payload })
             const fullTitle = payload.startLine === payload.endLine
                 ? t('chat.message.context.codeCommentLine', { file: payload.fileLabel, line: payload.startLine })
                 : t('chat.message.context.codeComment', { file: payload.fileLabel, start: payload.startLine, end: payload.endLine });
-            return <ContextCard icon="chat-1" summary={summary} title={fullTitle} body={payload.code} text={payload.text} />;
+            return <ContextCard icon="chat-1" summary={summary} title={fullTitle} body={payload.code} text={payload.text} mono {...shared} />;
         }
         case 'terminal':
             return (
@@ -83,6 +128,8 @@ const UserContextPart: React.FC<{ payload: ContextPartPayload }> = ({ payload })
                     })}
                     body={payload.output}
                     text=""
+                    mono
+                    {...shared}
                 />
             );
         case 'browser-annotation':
@@ -93,6 +140,7 @@ const UserContextPart: React.FC<{ payload: ContextPartPayload }> = ({ payload })
                     title={payload.pageUrl}
                     body={payload.prompt}
                     text={payload.text}
+                    {...shared}
                 />
             );
         case 'pr-comment':
@@ -102,6 +150,7 @@ const UserContextPart: React.FC<{ payload: ContextPartPayload }> = ({ payload })
                     summary={t('chat.message.context.prComment', { label: payload.label })}
                     body={payload.body}
                     text={payload.text}
+                    {...shared}
                 />
             );
         case 'pr-check':
@@ -111,6 +160,8 @@ const UserContextPart: React.FC<{ payload: ContextPartPayload }> = ({ payload })
                     summary={t('chat.message.context.prCheck', { label: payload.label })}
                     body={payload.output}
                     text={payload.text}
+                    mono
+                    {...shared}
                 />
             );
         case 'file-quote': {
@@ -120,7 +171,7 @@ const UserContextPart: React.FC<{ payload: ContextPartPayload }> = ({ payload })
                     ? t('chat.message.context.codeCommentLine', { file, line: payload.startLine })
                     : t('chat.message.context.codeComment', { file, start: payload.startLine, end: payload.endLine }))
                 : t('chat.message.context.fileQuote', { file });
-            return <ContextCard icon="chat-1" summary={summary} title={payload.fileLabel} body={payload.quote} text={payload.text} />;
+            return <ContextCard icon="chat-1" summary={summary} title={payload.fileLabel} body={payload.quote} text={payload.text} {...shared} />;
         }
         case 'chat-quote':
             return (
@@ -129,6 +180,7 @@ const UserContextPart: React.FC<{ payload: ContextPartPayload }> = ({ payload })
                     summary={t('chat.message.context.chatQuote')}
                     body={payload.quote}
                     text={payload.text}
+                    {...shared}
                 />
             );
         case 'github-issue':
diff --git a/packages/ui/src/components/chat/message/parts/UserTextPart.tsx b/packages/ui/src/components/chat/message/parts/UserTextPart.tsx
index 39058b67..8acd64aa 100644
--- a/packages/ui/src/components/chat/message/parts/UserTextPart.tsx
+++ b/packages/ui/src/components/chat/message/parts/UserTextPart.tsx
@@ -25,13 +25,22 @@ type UserTextPartProps = {
     messageId: string;
     isMobile: boolean;
     agentMention?: AgentMentionInfo;
+    /**
+     * Message-level collapse: when provided, all parts of the user message
+     * share one expanded state owned by the message body, expanding any part
+     * expands the whole message, and the message body renders the single
+     * collapse control. When absent the part collapses on its own (legacy
+     * single-part behavior).
+     */
+    messageExpanded?: boolean;
+    onExpandMessage?: () => void;
 };
 
 const normalizeUserMessageRenderingMode = (mode: unknown): 'markdown' | 'plain' => {
     return mode === 'markdown' ? 'markdown' : 'plain';
 };
 
-const UserTextPart: React.FC<UserTextPartProps> = ({ part, messageId, agentMention }) => {
+const UserTextPart: React.FC<UserTextPartProps> = ({ part, messageId, agentMention, messageExpanded, onExpandMessage }) => {
     // Structured context (inline comments, terminal selections, annotations,
     // PR context) renders as a dedicated block instead of raw prompt text.
     const contextPayload = React.useMemo(() => readContextPart(part), [part]);
@@ -51,7 +60,9 @@ const UserTextPart: React.FC<UserTextPartProps> = ({ part, messageId, agentMenti
     const effectiveDirectory = useEffectiveDirectory();
     const { t } = useI18n();
     const normalizedRenderingMode = normalizeUserMessageRenderingMode(userMessageRenderingMode);
-    const isCollapsed = collapsibleUserMessages && !isExpanded;
+    const isControlled = messageExpanded !== undefined;
+    const effectiveExpanded = messageExpanded ?? isExpanded;
+    const isCollapsed = collapsibleUserMessages && !effectiveExpanded;
     const textRef = React.useRef<HTMLDivElement>(null);
     const skillByName = React.useMemo(() => new Map(skills.map((skill) => [skill.name, skill])), [skills]);
 
@@ -78,7 +89,7 @@ const UserTextPart: React.FC<UserTextPartProps> = ({ part, messageId, agentMenti
     React.useEffect(() => {
         const el = textRef.current;
         if (!el) return;
-        if (!collapsibleUserMessages || isExpanded) return;
+        if (!collapsibleUserMessages || effectiveExpanded) return;
 
         const checkTruncation = () => {
             setIsTruncated(el.scrollHeight > el.clientHeight);
@@ -118,7 +129,7 @@ const UserTextPart: React.FC<UserTextPartProps> = ({ part, messageId, agentMenti
             mutationObserver.disconnect();
             resizeObserver.disconnect();
         };
-    }, [collapsibleUserMessages, textContent, isExpanded]);
+    }, [collapsibleUserMessages, textContent, effectiveExpanded]);
 
     React.useEffect(() => {
         if (!collapsibleUserMessages) {
@@ -151,11 +162,15 @@ const UserTextPart: React.FC<UserTextPartProps> = ({ part, messageId, agentMenti
         // Measure at click time instead of trusting the observed flag: whether
         // the text is clipped right now is what decides if expanding does
         // anything, and the flag can still be catching up on a fresh message.
-        if (collapsibleUserMessages && !isExpanded && element.scrollHeight > element.clientHeight) {
+        if (collapsibleUserMessages && !effectiveExpanded && element.scrollHeight > element.clientHeight) {
             setIsTruncated(true);
-            setIsExpanded(true);
+            if (isControlled) {
+                onExpandMessage?.();
+            } else {
+                setIsExpanded(true);
+            }
         }
-    }, [collapsibleUserMessages, hasActiveSelectionInElement, isExpanded, openSkill]);
+    }, [collapsibleUserMessages, effectiveExpanded, hasActiveSelectionInElement, isControlled, onExpandMessage, openSkill]);
 
     const handleCollapse = React.useCallback((event: React.MouseEvent) => {
         event.stopPropagation();
@@ -231,7 +246,13 @@ const UserTextPart: React.FC<UserTextPartProps> = ({ part, messageId, agentMenti
     }, [agentMention, openSkill, skillByName, textContent]);
 
     if (contextPayload) {
-        return <UserContextPart payload={contextPayload} />;
+        return (
+            <UserContextPart
+                payload={contextPayload}
+                collapsed={isCollapsed}
+                onExpand={isControlled ? onExpandMessage : () => setIsExpanded(true)}
+            />
+        );
     }
 
     if ((!textContent || textContent.trim().length === 0) && terminalContextState.contexts.length === 0) {
@@ -240,7 +261,7 @@ const UserTextPart: React.FC<UserTextPartProps> = ({ part, messageId, agentMenti
 
     return (
         <div className="relative" key={part.id || `${messageId}-user-text`}>
-            {collapsibleUserMessages && isExpanded && (
+            {collapsibleUserMessages && !isControlled && isExpanded && (
                 <button
                     type="button"
                     onClick={handleCollapse}
@@ -253,10 +274,10 @@ const UserTextPart: React.FC<UserTextPartProps> = ({ part, messageId, agentMenti
             <div
                 className={cn(
                     "break-words font-sans typography-markdown-body",
-                    isExpanded && "pb-3",
+                    !isControlled && isExpanded && "pb-3",
                     normalizedRenderingMode === 'plain' && 'whitespace-pre-wrap',
                     isCollapsed && "line-clamp-2",
-                    collapsibleUserMessages && isTruncated && !isExpanded && "cursor-pointer"
+                    collapsibleUserMessages && isTruncated && !effectiveExpanded && "cursor-pointer"
                 )}
                 ref={textRef}
                 onClick={handleClick}