feat(chat): align activity timing UI with hover-only end timestamps (#557)

* feat(chat): add shared activity timestamp formatter

* feat(chat): pass assistant created timestamp to message body

* feat(chat): render footer timestamp beside elapsed time

* feat(chat): pass timing metadata in reasoning text blocks

* feat(chat): propagate justification timing to timeline block

* feat(chat): show thinking duration with hover end time

* feat(chat): reveal tool end time on activity hover

packages/ui/src/components/chat/ChatMessage.tsx

@@ -389,6 +389,11 @@ const ChatMessage: React.FC<ChatMessageProps> = ({
         return typeof timeInfo?.completed === 'number' ? timeInfo.completed : null;
     }, [message.info.time]);
 
+    const messageCreatedAt = React.useMemo(() => {
+        const timeInfo = message.info.time as { created?: number } | undefined;
+        return typeof timeInfo?.created === 'number' ? timeInfo.created : null;
+    }, [message.info.time]);
+
     const isMessageCompleted = React.useMemo(() => {
         if (isUser) return true;
         return Boolean(messageCompletedAt && messageCompletedAt > 0);
@@ -1004,6 +1009,7 @@ const ChatMessage: React.FC<ChatMessageProps> = ({
                                 isMessageCompleted={isMessageCompleted}
                                 messageFinish={messageFinish}
                                 messageCompletedAt={messageCompletedAt ?? undefined}
+                                messageCreatedAt={messageCreatedAt ?? undefined}
                                 syntaxTheme={syntaxTheme}
                                 isMobile={isMobile}
                                 hasTouchInput={hasTouchInput}

packages/ui/src/components/chat/message/MessageBody.tsx

@@ -28,6 +28,7 @@ import { useMessageTTS } from '@/hooks/useMessageTTS';
 import { useConfigStore } from '@/stores/useConfigStore';
 import { TextSelectionMenu } from './TextSelectionMenu';
 import { copyTextToClipboard } from '@/lib/clipboard';
+import { formatTimestampForDisplay } from './timeFormat';
 
 type SubtaskPartLike = Part & {
     type: 'subtask';
@@ -257,6 +258,7 @@ interface MessageBodyProps {
     isMessageCompleted: boolean;
     messageFinish?: string;
     messageCompletedAt?: number;
+    messageCreatedAt?: number;
 
     syntaxTheme: { [key: string]: React.CSSProperties };
 
@@ -508,6 +510,7 @@ const AssistantMessageBody: React.FC<Omit<MessageBodyProps, 'isUser'>> = ({
     isMessageCompleted,
     messageFinish,
     messageCompletedAt,
+    messageCreatedAt,
 
     syntaxTheme,
     isMobile,
@@ -1123,6 +1126,16 @@ const AssistantMessageBody: React.FC<Omit<MessageBodyProps, 'isUser'>> = ({
         return formatTurnDuration(messageCompletedAt - userCreatedAt);
     }, [isLastAssistantInTurn, hasStopFinish, turnGroupingContext?.userMessageCreatedAt, messageCompletedAt]);
 
+    const footerTimestamp = React.useMemo(() => {
+        const timestamp = typeof messageCompletedAt === 'number' && messageCompletedAt > 0
+            ? messageCompletedAt
+            : (typeof messageCreatedAt === 'number' && messageCreatedAt > 0 ? messageCreatedAt : null);
+        if (timestamp === null) return null;
+
+        const formatted = formatTimestampForDisplay(timestamp);
+        return formatted.length > 0 ? formatted : null;
+    }, [messageCompletedAt, messageCreatedAt]);
+
     const footerButtons = (
          <>
               {onCopyMessage && (
@@ -1259,12 +1272,17 @@ const AssistantMessageBody: React.FC<Omit<MessageBodyProps, 'isUser'>> = ({
                                         <div className="flex items-center gap-1.5">
                                             {footerButtons}
                                         </div>
-                                        {turnDurationText ? (
+                                        <div className="flex items-center gap-1.5">
-                                            <span className="text-sm text-muted-foreground/60 tabular-nums flex items-center gap-1">
+                                            {turnDurationText ? (
-                                                <RiHourglassLine className="h-3.5 w-3.5" />
+                                                <span className="text-sm text-muted-foreground/60 tabular-nums flex items-center gap-1">
-                                                {turnDurationText}
+                                                    <RiHourglassLine className="h-3.5 w-3.5" />
-                                            </span>
+                                                    {turnDurationText}
-                                        ) : null}
+                                                </span>
+                                            ) : null}
+                                            {footerTimestamp ? (
+                                                <span className="text-sm text-muted-foreground/60 tabular-nums">{footerTimestamp}</span>
+                                            ) : null}
+                                        </div>
                                     </div>
                                 )}
                             </div>
@@ -1277,12 +1295,17 @@ const AssistantMessageBody: React.FC<Omit<MessageBodyProps, 'isUser'>> = ({
                         <div className="flex items-center gap-1.5">
                             {footerButtons}
                         </div>
-                        {turnDurationText ? (
+                        <div className="flex items-center gap-1.5">
-                            <span className="text-sm text-muted-foreground/60 tabular-nums flex items-center gap-1">
+                            {turnDurationText ? (
-                                <RiHourglassLine className="h-3.5 w-3.5" />
+                                <span className="text-sm text-muted-foreground/60 tabular-nums flex items-center gap-1">
-                                {turnDurationText}
+                                    <RiHourglassLine className="h-3.5 w-3.5" />
-                            </span>
+                                    {turnDurationText}
-                        ) : null}
+                                </span>
+                            ) : null}
+                            {footerTimestamp ? (
+                                <span className="text-sm text-muted-foreground/60 tabular-nums">{footerTimestamp}</span>
+                            ) : null}
+                        </div>
                     </div>
                 )}
 

packages/ui/src/components/chat/message/parts/AssistantTextPart.tsx

@@ -61,6 +61,7 @@ const AssistantTextPart: React.FC<AssistantTextPartProps> = ({
                 variant="justification"
                 onContentChange={onContentChange}
                 blockId={part.id || `${messageId}-reasoning-text`}
+                time={time}
             />
         );
     }

packages/ui/src/components/chat/message/parts/JustificationBlock.tsx

@@ -3,7 +3,7 @@ import type { Part } from '@opencode-ai/sdk/v2';
 import type { ContentChangeReason } from '@/hooks/useChatScrollManager';
 import { ReasoningTimelineBlock } from './ReasoningPart';
 
-type PartWithText = Part & { text?: string; content?: string };
+type PartWithText = Part & { text?: string; content?: string; time?: { start?: number; end?: number } };
 
 const cleanJustificationText = (text: string): string => {
     if (typeof text !== 'string' || text.trim().length === 0) {
@@ -32,6 +32,7 @@ const JustificationBlock: React.FC<JustificationBlockProps> = ({
     const partWithText = part as PartWithText;
     const rawText = partWithText.text || partWithText.content || '';
     const textContent = React.useMemo(() => cleanJustificationText(rawText), [rawText]);
+    const time = partWithText.time;
 
     // Don't render if there's no text content
     if (!textContent || textContent.trim().length === 0) {
@@ -44,6 +45,7 @@ const JustificationBlock: React.FC<JustificationBlockProps> = ({
             variant="justification"
             onContentChange={onContentChange}
             blockId={part.id || `${messageId}-justification`}
+            time={time}
         />
     );
 };

packages/ui/src/components/chat/message/parts/ReasoningPart.tsx

@@ -3,10 +3,11 @@ import type { ComponentType } from 'react';
 import type { Part } from '@opencode-ai/sdk/v2';
 import { RiArrowDownSLine, RiArrowRightSLine, RiBrainAi3Line, RiChatAi3Line } from '@remixicon/react';
 import { cn } from '@/lib/utils';
+import { formatTimestampForDisplay } from '../timeFormat';
 import type { ContentChangeReason } from '@/hooks/useChatScrollManager';
 import { ScrollableOverlay } from '@/components/ui/ScrollableOverlay';
 
-type PartWithText = Part & { text?: string; content?: string };
+type PartWithText = Part & { text?: string; content?: string; time?: { start?: number; end?: number } };
 
 export type ReasoningVariant = 'thinking' | 'justification';
 
@@ -56,11 +57,37 @@ const getReasoningSummary = (text: string): string => {
     return trimmed.substring(0, cutoff).trim();
 };
 
+const formatDuration = (start: number, end?: number, now: number = Date.now()): string => {
+    const duration = end ? end - start : now - start;
+    const seconds = duration / 1000;
+    const displaySeconds = seconds < 0.05 && end !== undefined ? 0.1 : seconds;
+    return `${displaySeconds.toFixed(1)}s`;
+};
+
+const LiveDuration: React.FC<{ start: number; end?: number; active: boolean }> = ({ start, end, active }) => {
+    const [now, setNow] = React.useState(() => Date.now());
+
+    React.useEffect(() => {
+        if (!active) {
+            return;
+        }
+
+        const timer = window.setInterval(() => {
+            setNow(Date.now());
+        }, 100);
+
+        return () => window.clearInterval(timer);
+    }, [active]);
+
+    return <>{formatDuration(start, end, now)}</>;
+};
+
 type ReasoningTimelineBlockProps = {
     text: string;
     variant: ReasoningVariant;
     onContentChange?: (reason?: ContentChangeReason) => void;
     blockId: string;
+    time?: { start?: number; end?: number };
 };
 
 export const ReasoningTimelineBlock: React.FC<ReasoningTimelineBlockProps> = ({
@@ -68,11 +95,22 @@ export const ReasoningTimelineBlock: React.FC<ReasoningTimelineBlockProps> = ({
     variant,
     onContentChange,
     blockId,
+    time,
 }) => {
     const [isExpanded, setIsExpanded] = React.useState(false);
 
     const summary = React.useMemo(() => getReasoningSummary(text), [text]);
     const { label, Icon } = variantConfig[variant];
+    const timeStart = typeof time?.start === 'number' && Number.isFinite(time.start) ? time.start : undefined;
+    const timeEnd = typeof time?.end === 'number' && Number.isFinite(time.end) ? time.end : undefined;
+    const endedTimestampText = React.useMemo(() => {
+        if (typeof timeEnd !== 'number') {
+            return null;
+        }
+
+        const formatted = formatTimestampForDisplay(timeEnd);
+        return formatted.length > 0 ? formatted : null;
+    }, [timeEnd]);
 
     React.useEffect(() => {
         if (text.trim().length === 0) {
@@ -117,11 +155,30 @@ export const ReasoningTimelineBlock: React.FC<ReasoningTimelineBlockProps> = ({
                     <span className="typography-meta font-medium">{label}</span>
                 </div>
 
-                {summary && (
+                {(summary || typeof timeStart === 'number' || endedTimestampText) ? (
-                    <div className="flex-1 min-w-0 typography-meta text-muted-foreground/70">
+                    <div className="flex items-center gap-1 flex-1 min-w-0 typography-meta text-muted-foreground/70">
-                        <span className="truncate block italic">{summary}</span>
+                        {summary ? <span className="truncate italic">{summary}</span> : null}
+                        {typeof timeStart === 'number' ? (
+                            <span className="text-muted-foreground/80 flex-shrink-0 tabular-nums">
+                                <LiveDuration
+                                    start={timeStart}
+                                    end={timeEnd}
+                                    active={typeof timeEnd !== 'number'}
+                                />
+                            </span>
+                        ) : null}
+                        {endedTimestampText ? (
+                            <span
+                                className={cn(
+                                    'text-muted-foreground/70 flex-shrink-0 tabular-nums transition-opacity duration-150',
+                                    'opacity-0 group-hover/tool:opacity-100'
+                                )}
+                            >
+                                {endedTimestampText}
+                            </span>
+                        ) : null}
                     </div>
-                )}
+                ) : null}
             </div>
 
             {isExpanded && (
@@ -159,6 +216,7 @@ const ReasoningPart: React.FC<ReasoningPartProps> = ({
     const partWithText = part as PartWithText;
     const rawText = partWithText.text || partWithText.content || '';
     const textContent = React.useMemo(() => cleanReasoningText(rawText), [rawText]);
+    const time = partWithText.time;
 
     // Show reasoning even if time.end isn't set yet (during streaming)
     // Only hide if there's no text content
@@ -172,6 +230,7 @@ const ReasoningPart: React.FC<ReasoningPartProps> = ({
             variant="thinking"
             onContentChange={onContentChange}
             blockId={part.id || `${messageId}-reasoning`}
+            time={time}
         />
     );
 };

packages/ui/src/components/chat/message/parts/ToolPart.tsx

@@ -4,6 +4,7 @@ import { RuntimeAPIContext } from '@/contexts/runtimeAPIContext';
 import { RiAiAgentLine, RiArrowDownSLine, RiArrowRightSLine, RiBookLine, RiExternalLinkLine, RiFileEditLine, RiFileList2Line, RiFileSearchLine, RiFileTextLine, RiFolder6Line, RiGitBranchLine, RiGlobalLine, RiListCheck2, RiListCheck3, RiMenuSearchLine, RiPencilLine, RiSurveyLine, RiTaskLine, RiTerminalBoxLine, RiToolsLine } from '@remixicon/react';
 import { File as PierreFile, PatchDiff } from '@pierre/diffs/react';
 import { cn } from '@/lib/utils';
+import { formatTimestampForDisplay } from '../timeFormat';
 import { SimpleMarkdownRenderer } from '../../MarkdownRenderer';
 import { getToolMetadata, getLanguageFromExtension, isImageFile, getImageMimeType } from '@/lib/toolHelpers';
 import type { ToolPart as ToolPartType, ToolState as ToolStateUnion } from '@opencode-ai/sdk/v2';
@@ -1419,6 +1420,15 @@ const ToolPart: React.FC<ToolPartProps> = ({
     const effectiveTimeStart = isTaskTool ? (pinnedTaskTime.start ?? time?.start) : time?.start;
     const effectiveTimeEnd = isTaskTool ? (pinnedTaskTime.end ?? time?.end) : time?.end;
 
+    const endedTimestampText = React.useMemo(() => {
+        if (typeof effectiveTimeEnd !== 'number' || !Number.isFinite(effectiveTimeEnd)) {
+            return null;
+        }
+
+        const formatted = formatTimestampForDisplay(effectiveTimeEnd);
+        return formatted.length > 0 ? formatted : null;
+    }, [effectiveTimeEnd]);
+
     const taskOutputString = React.useMemo(() => {
         return typeof stateWithData.output === 'string' ? stateWithData.output : undefined;
     }, [stateWithData.output]);
@@ -1667,7 +1677,7 @@ const ToolPart: React.FC<ToolPartProps> = ({
                         </span>
                     )}
                     {typeof effectiveTimeStart === 'number' && (
-                        <span className="text-muted-foreground/80 flex-shrink-0">
+                        <span className="text-muted-foreground/80 flex-shrink-0 tabular-nums">
                             <LiveDuration
                                 start={effectiveTimeStart}
                                 end={typeof effectiveTimeEnd === 'number' ? effectiveTimeEnd : undefined}
@@ -1675,6 +1685,16 @@ const ToolPart: React.FC<ToolPartProps> = ({
                             />
                         </span>
                     )}
+                    {endedTimestampText ? (
+                        <span
+                            className={cn(
+                                'text-muted-foreground/70 flex-shrink-0 tabular-nums transition-opacity duration-150',
+                                'opacity-0 group-hover/tool:opacity-100'
+                            )}
+                        >
+                            {endedTimestampText}
+                        </span>
+                    ) : null}
                 </div>
             </div>
 

packages/ui/src/components/chat/message/timeFormat.ts

@@ -0,0 +1,34 @@
+const pad2 = (value: number): string => String(value).padStart(2, '0');
+
+const isSameDay = (left: Date, right: Date): boolean => {
+    return (
+        left.getFullYear() === right.getFullYear() &&
+        left.getMonth() === right.getMonth() &&
+        left.getDate() === right.getDate()
+    );
+};
+
+const isValidTimestamp = (timestamp: number): boolean => {
+    return Number.isFinite(timestamp) && !Number.isNaN(new Date(timestamp).getTime());
+};
+
+export const formatTimestampForDisplay = (timestamp: number): string => {
+    if (!isValidTimestamp(timestamp)) {
+        return '';
+    }
+
+    const date = new Date(timestamp);
+    const now = new Date();
+
+    const timePart = `${pad2(date.getHours())}:${pad2(date.getMinutes())}:${pad2(date.getSeconds())}`;
+
+    if (isSameDay(date, now)) {
+        return timePart;
+    }
+
+    const yearPart = String(date.getFullYear()).slice(-2);
+    const monthPart = pad2(date.getMonth() + 1);
+    const dayPart = pad2(date.getDate());
+
+    return `${yearPart}-${monthPart}-${dayPart} ${timePart}`;
+};