fix: reveal message actions with timestamps on hover (#642)

Message rows should stay visually quiet until the user needs copy or fork controls. The action row now appears on message hover/focus, uses icon-sized controls, and shows the message timestamp beside the actions with locale-aware recent and historical formats.

Constraint: Desktop chat actions already own copy and fork affordances, so the change keeps that surface instead of adding a separate always-visible timestamp row.
Rejected: Keep text-labeled Copy buttons | the row remained too visually heavy for every message.
Confidence: high
Scope-risk: narrow
Directive: Keep copy, fork, and timestamp as one hover/focus metadata row unless the message layout is redesigned as a whole.
Tested: bun run check:desktop
Not-tested: Live Tauri native packaging

desktop/src/components/chat/AssistantMessage.tsx

@@ -17,11 +17,12 @@ type Props = {
   isStreaming?: boolean
   branchAction?: MessageBranchAction
   sessionId?: string
+  timestamp?: number
 }
 
 const MAX_CARDS = 3
 
-export const AssistantMessage = memo(function AssistantMessage({ content, isStreaming, branchAction, sessionId }: Props) {
+export const AssistantMessage = memo(function AssistantMessage({ content, isStreaming, branchAction, sessionId, timestamp }: Props) {
   const t = useTranslation()
   const workDir = useWorkspacePanelStore((s) => (sessionId ? s.statusBySession[sessionId]?.workDir : undefined))
 
@@ -107,6 +108,7 @@ export const AssistantMessage = memo(function AssistantMessage({ content, isStre
           copyLabel="Copy reply"
           branchAction={branchAction}
           align="start"
+          timestamp={timestamp}
         />
       </div>
     </div>

desktop/src/components/chat/MessageActionBar.tsx

@@ -1,4 +1,7 @@
-import { GitFork } from 'lucide-react'
+import { Check, Copy, GitFork } from 'lucide-react'
+import { useTranslation } from '../../i18n'
+import { useSettingsStore } from '../../stores/settingsStore'
+import { formatExactMessageTimestamp, formatMessageTimestamp } from '../../lib/formatMessageTimestamp'
 import { CopyButton } from '../shared/CopyButton'
 
 export type MessageBranchAction = {
@@ -12,6 +15,7 @@ type Props = {
   copyLabel: string
   branchAction?: MessageBranchAction
   align?: 'start' | 'end'
+  timestamp?: number
 }
 
 export function MessageActionBar({
@@ -19,8 +23,17 @@ export function MessageActionBar({
   copyLabel,
   branchAction,
   align = 'start',
+  timestamp,
 }: Props) {
+  const t = useTranslation()
+  const locale = useSettingsStore((state) => state.locale)
   const hasCopy = Boolean(copyText?.trim())
+  const timeLabel = typeof timestamp === 'number'
+    ? formatMessageTimestamp(timestamp, t, locale)
+    : ''
+  const exactTimeLabel = typeof timestamp === 'number'
+    ? formatExactMessageTimestamp(timestamp, locale)
+    : ''
 
   if (!hasCopy && !branchAction) return null
 
@@ -28,18 +41,18 @@ export function MessageActionBar({
     <div
       data-message-actions
       data-align={align}
-      className={`flex w-full opacity-0 transition-opacity duration-200 group-hover:opacity-100 group-focus-within:opacity-100 ${
+      className={`invisible flex w-full opacity-0 transition-opacity duration-150 group-hover:visible group-hover:opacity-100 group-focus-within:visible group-focus-within:opacity-100 ${
         align === 'end' ? 'justify-end' : 'justify-start'
       }`}
     >
-      <div className="flex items-center gap-1.5">
+      <div className="flex min-h-7 items-center gap-1.5">
         {hasCopy ? (
           <CopyButton
             text={copyText!}
             label={copyLabel}
-            displayLabel="Copy"
-            displayCopiedLabel="Copied"
-            className="inline-flex min-h-7 items-center rounded-full border border-[var(--color-border)]/70 bg-[var(--color-surface-container-low)] px-2.5 text-[11px] font-medium text-[var(--color-text-tertiary)] transition-colors hover:border-[var(--color-brand)]/35 hover:text-[var(--color-text-primary)] focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-[var(--color-brand)]/35"
+            displayLabel={<Copy size={13} strokeWidth={2.2} aria-hidden="true" />}
+            displayCopiedLabel={<Check size={13} strokeWidth={2.4} aria-hidden="true" />}
+            className="inline-flex h-7 w-7 items-center justify-center rounded-full border border-transparent bg-transparent text-[var(--color-text-tertiary)] transition-colors hover:border-[var(--color-brand)]/30 hover:bg-[var(--color-surface-container-low)] hover:text-[var(--color-text-primary)] focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-[var(--color-brand)]/35"
           />
         ) : null}
         {branchAction ? (
@@ -49,11 +62,19 @@ export function MessageActionBar({
             disabled={branchAction.loading}
             aria-label={branchAction.label}
             title={branchAction.label}
-            className="inline-flex h-7 w-7 items-center justify-center rounded-full border border-[var(--color-border)]/70 bg-[var(--color-surface-container-low)] text-[var(--color-text-tertiary)] transition-colors hover:border-[var(--color-brand)]/35 hover:text-[var(--color-text-primary)] focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-[var(--color-brand)]/35 disabled:cursor-wait disabled:opacity-60"
+            className="inline-flex h-7 w-7 items-center justify-center rounded-full border border-transparent bg-transparent text-[var(--color-text-tertiary)] transition-colors hover:border-[var(--color-brand)]/30 hover:bg-[var(--color-surface-container-low)] hover:text-[var(--color-text-primary)] focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-[var(--color-brand)]/35 disabled:cursor-wait disabled:opacity-60"
           >
             <GitFork size={13} strokeWidth={2.2} aria-hidden="true" />
           </button>
         ) : null}
+        {timeLabel ? (
+          <span
+            className="ml-1 inline-flex items-center text-[11px] font-medium tabular-nums text-[var(--color-text-tertiary)]"
+            title={exactTimeLabel || timeLabel}
+          >
+            {timeLabel}
+          </span>
+        ) : null}
       </div>
     </div>
   )

desktop/src/components/chat/MessageList.test.tsx

@@ -2665,6 +2665,9 @@ describe('MessageList nested tool calls', () => {
   })
 
   it('keeps user actions anchored to the right bubble and assistant actions to the left bubble', () => {
+    const now = new Date('2026-05-29T16:00:00+08:00').getTime()
+    vi.spyOn(Date, 'now').mockReturnValue(now)
+
     useChatStore.setState({
       sessions: {
         [ACTIVE_TAB]: makeSessionState({
@@ -2673,13 +2676,13 @@ describe('MessageList nested tool calls', () => {
               id: 'user-1',
               type: 'user_text',
               content: '请把这条 prompt 放在右侧',
-              timestamp: 1,
+              timestamp: now - 5 * 60_000,
             },
             {
               id: 'assistant-1',
               type: 'assistant_text',
               content: '这条回复应该停在左侧。',
-              timestamp: 2,
+              timestamp: now - 2 * 60 * 60_000,
             },
           ],
         }),
@@ -2700,6 +2703,10 @@ describe('MessageList nested tool calls', () => {
     expect(assistantShell?.className).not.toContain('ml-10')
     expect(userActions?.getAttribute('data-align')).toBe('end')
     expect(assistantActions?.getAttribute('data-align')).toBe('start')
+    expect(userActions?.className).toContain('invisible')
+    expect(userActions?.className).toContain('group-hover:visible')
+    expect(within(userActions as HTMLElement).getByText('5m ago')).toBeTruthy()
+    expect(within(assistantActions as HTMLElement).getByText('2h ago')).toBeTruthy()
   })
 
   it('uses the document column for markdown-heavy assistant replies', () => {

desktop/src/components/chat/MessageList.tsx

@@ -1948,6 +1948,7 @@ export const MessageBlock = memo(function MessageBlock({
             content={message.content}
             attachments={message.attachments}
             branchAction={branchAction}
+            timestamp={message.timestamp}
           />
         </SelectableChatMessage>
       )
@@ -1959,7 +1960,12 @@ export const MessageBlock = memo(function MessageBlock({
           role="assistant"
           content={message.content}
         >
-          <AssistantMessage content={message.content} branchAction={branchAction} sessionId={sessionId ?? undefined} />
+          <AssistantMessage
+            content={message.content}
+            branchAction={branchAction}
+            sessionId={sessionId ?? undefined}
+            timestamp={message.timestamp}
+          />
         </SelectableChatMessage>
       )
     case 'thinking':

desktop/src/components/chat/UserMessage.tsx

@@ -7,9 +7,10 @@ type Props = {
   content: string
   attachments?: UIAttachment[]
   branchAction?: MessageBranchAction
+  timestamp?: number
 }
 
-export const UserMessage = memo(function UserMessage({ content, attachments, branchAction }: Props) {
+export const UserMessage = memo(function UserMessage({ content, attachments, branchAction, timestamp }: Props) {
   const hasText = content.trim().length > 0
 
   return (
@@ -41,6 +42,7 @@ export const UserMessage = memo(function UserMessage({ content, attachments, bra
             copyLabel="Copy prompt"
             branchAction={branchAction}
             align="end"
+            timestamp={timestamp}
           />
         )}
       </div>

desktop/src/components/shared/CopyButton.tsx

@@ -1,12 +1,12 @@
-import { useEffect, useState } from 'react'
+import { useEffect, useState, type ReactNode } from 'react'
 import { copyTextToClipboard } from '../chat/clipboard'
 
 type Props = {
   text: string
   label?: string
   copiedLabel?: string
-  displayLabel?: string
-  displayCopiedLabel?: string
+  displayLabel?: ReactNode
+  displayCopiedLabel?: ReactNode
   className?: string
 }
 

desktop/src/lib/formatMessageTimestamp.test.ts

@@ -0,0 +1,29 @@
+import { describe, expect, it } from 'vitest'
+import { translate, type Locale } from '../i18n'
+import { formatMessageTimestamp } from './formatMessageTimestamp'
+
+const t = (locale: Locale) => (
+  key: Parameters<typeof translate>[1],
+  params?: Parameters<typeof translate>[2],
+) => translate(locale, key, params)
+
+describe('formatMessageTimestamp', () => {
+  const now = new Date(2026, 4, 29, 16, 0).getTime()
+
+  it('uses relative labels for recent messages', () => {
+    expect(formatMessageTimestamp(now - 5 * 60_000, t('zh'), 'zh', now)).toBe('5分钟前')
+    expect(formatMessageTimestamp(now - 2 * 60 * 60_000, t('en'), 'en', now)).toBe('2h ago')
+  })
+
+  it('uses weekday and clock time for recent history', () => {
+    const value = new Date(2026, 4, 24, 15, 50).getTime()
+
+    expect(formatMessageTimestamp(value, t('zh'), 'zh', now)).toBe('星期日15:50')
+  })
+
+  it('includes the calendar date for older messages', () => {
+    const value = new Date(2026, 3, 20, 9, 30).getTime()
+
+    expect(formatMessageTimestamp(value, t('zh'), 'zh', now)).toBe('4月20日 09:30')
+  })
+})

desktop/src/lib/formatMessageTimestamp.ts

@@ -0,0 +1,100 @@
+import type { Locale, TranslationKey } from '../i18n'
+
+type Translator = (key: TranslationKey, params?: Record<string, string | number>) => string
+
+const MINUTE_MS = 60_000
+const HOUR_MS = 60 * MINUTE_MS
+const DAY_MS = 24 * HOUR_MS
+
+export function formatMessageTimestamp(
+  value: number | string | Date,
+  t: Translator,
+  locale: Locale,
+  now = Date.now(),
+): string {
+  const date = coerceDate(value)
+  if (!date) return ''
+
+  const timestamp = date.getTime()
+  const diff = now - timestamp
+
+  if (diff >= 0 && diff < MINUTE_MS) return t('session.timeJustNow')
+  if (diff >= MINUTE_MS && diff < HOUR_MS) {
+    return t('session.timeMinutes', { n: Math.floor(diff / MINUTE_MS) })
+  }
+  if (diff >= HOUR_MS && diff < DAY_MS) {
+    return t('session.timeHours', { n: Math.floor(diff / HOUR_MS) })
+  }
+  if (diff >= DAY_MS && diff < 7 * DAY_MS) {
+    return formatWeekdayTime(date, locale)
+  }
+
+  return isSameLocalYear(date, new Date(now))
+    ? formatMonthDayTime(date, locale)
+    : formatYearMonthDayTime(date, locale)
+}
+
+export function formatExactMessageTimestamp(value: number | string | Date, locale: Locale): string {
+  const date = coerceDate(value)
+  if (!date) return ''
+  return new Intl.DateTimeFormat(localeToIntl(locale), {
+    year: 'numeric',
+    month: 'numeric',
+    day: 'numeric',
+    hour: '2-digit',
+    minute: '2-digit',
+  }).format(date)
+}
+
+function coerceDate(value: number | string | Date): Date | null {
+  const date = value instanceof Date ? value : new Date(value)
+  return Number.isFinite(date.getTime()) ? date : null
+}
+
+function localeToIntl(locale: Locale): string {
+  return locale === 'zh' ? 'zh-CN' : 'en-US'
+}
+
+function formatWeekdayTime(date: Date, locale: Locale): string {
+  const intlLocale = localeToIntl(locale)
+  const weekday = new Intl.DateTimeFormat(intlLocale, { weekday: locale === 'zh' ? 'long' : 'short' }).format(date)
+  const time = formatClockTime(date, intlLocale)
+  return locale === 'zh' ? `${weekday}${time}` : `${weekday} ${time}`
+}
+
+function formatMonthDayTime(date: Date, locale: Locale): string {
+  const intlLocale = localeToIntl(locale)
+  if (locale === 'zh') {
+    return `${date.getMonth() + 1}月${date.getDate()}日 ${formatClockTime(date, intlLocale)}`
+  }
+  const day = new Intl.DateTimeFormat(intlLocale, {
+    month: 'short',
+    day: 'numeric',
+  }).format(date)
+  return `${day} ${formatClockTime(date, intlLocale)}`
+}
+
+function formatYearMonthDayTime(date: Date, locale: Locale): string {
+  const intlLocale = localeToIntl(locale)
+  if (locale === 'zh') {
+    return `${date.getFullYear()}年${date.getMonth() + 1}月${date.getDate()}日 ${formatClockTime(date, intlLocale)}`
+  }
+  const day = new Intl.DateTimeFormat(intlLocale, {
+    year: 'numeric',
+    month: 'short',
+    day: 'numeric',
+  }).format(date)
+  return `${day} ${formatClockTime(date, intlLocale)}`
+}
+
+function formatClockTime(date: Date, locale: string): string {
+  return new Intl.DateTimeFormat(locale, {
+    hour: '2-digit',
+    minute: '2-digit',
+    hour12: false,
+  }).format(date)
+}
+
+function isSameLocalYear(a: Date, b: Date): boolean {
+  return a.getFullYear() === b.getFullYear()
+}