diff --git a/frontend/src/app/pages/AgentChat/tool-bubbles/CompactMcpBubble.tsx b/frontend/src/app/pages/AgentChat/tool-bubbles/CompactMcpBubble.tsx
index 606ddbac..6a66afd3 100644
--- a/frontend/src/app/pages/AgentChat/tool-bubbles/CompactMcpBubble.tsx
+++ b/frontend/src/app/pages/AgentChat/tool-bubbles/CompactMcpBubble.tsx
@@ -4,7 +4,7 @@ import Typography from '@mui/material/Typography';
 import Collapse from '@mui/material/Collapse';
 import IconButton from '@mui/material/IconButton';
 import ExpandMoreIcon from '@mui/icons-material/ExpandMore';
-import ExpandLessIcon from '@mui/icons-material/ExpandLess';
+import { COLLAPSE_MS, COLLAPSE_EASE, chevronSx, shimmerTextSx } from './toolRowMotion';
 import ErrorOutlineIcon from '@mui/icons-material/ErrorOutline';
 import BlockIcon from '@mui/icons-material/Block';
 import SearchIcon from '@mui/icons-material/Search';
@@ -101,6 +101,7 @@ export const CompactMcpBubble: React.FC<CompactMcpBubbleProps> = ({
                 fontWeight: isPending ? 600 : 500,
                 flexShrink: 0,
                 transition: 'color 0.25s ease',
+                ...(isPending ? shimmerTextSx(c.accent.primary) : {}),
               }}
             >
               {serviceLabel}
@@ -155,7 +156,7 @@ export const CompactMcpBubble: React.FC<CompactMcpBubbleProps> = ({
           )}
           {canToggleDetails && (
             <IconButton size="small" sx={{ color: c.text.tertiary, p: 0.15, flexShrink: 0, opacity: 0, transition: 'opacity 120ms', '.osw-mcp-row:hover &': { opacity: 1 }, ...(showBody ? { opacity: 1 } : {}) }}>
-              {showBody ? <ExpandLessIcon sx={{ fontSize: 16 }} /> : <ExpandMoreIcon sx={{ fontSize: 16 }} />}
+              <ExpandMoreIcon sx={{ fontSize: 16, ...chevronSx(showBody) }} />
             </IconButton>
           )}
         </Box>
@@ -177,10 +178,11 @@ export const CompactMcpBubble: React.FC<CompactMcpBubbleProps> = ({
         )}
       </Box>
 
-      <Collapse in={showBody && canToggleDetails}>
+      <Collapse in={showBody && canToggleDetails} timeout={COLLAPSE_MS} easing={COLLAPSE_EASE}>
         <Box
           sx={{
             bgcolor: tc.TERM_BG,
+            borderRadius: 1.5,
             maxHeight: '60vh',
             overflowY: 'auto',
             overflowX: 'hidden',
diff --git a/frontend/src/app/pages/AgentChat/tool-bubbles/DefaultToolBubble.tsx b/frontend/src/app/pages/AgentChat/tool-bubbles/DefaultToolBubble.tsx
index b26cc839..7c5df586 100644
--- a/frontend/src/app/pages/AgentChat/tool-bubbles/DefaultToolBubble.tsx
+++ b/frontend/src/app/pages/AgentChat/tool-bubbles/DefaultToolBubble.tsx
@@ -4,7 +4,6 @@ import Typography from '@mui/material/Typography';
 import Collapse from '@mui/material/Collapse';
 import IconButton from '@mui/material/IconButton';
 import ExpandMoreIcon from '@mui/icons-material/ExpandMore';
-import ExpandLessIcon from '@mui/icons-material/ExpandLess';
 import TerminalIcon from '@mui/icons-material/Terminal';
 import ErrorOutlineIcon from '@mui/icons-material/ErrorOutline';
 import BlockIcon from '@mui/icons-material/Block';
@@ -25,6 +24,7 @@ import { domainFromUrl } from './SourceFavicons';
 import { DomainIcon } from './DomainIcon';
 import VendoredToolUi from '@toolui/VendoredToolUi';
 import WidgetCopyChip from '../tool-ui/WidgetCopyChip';
+import { COLLAPSE_MS, COLLAPSE_EASE, chevronSx, shimmerTextSx, railEnterSx } from './toolRowMotion';
 
 interface DefaultToolBubbleProps {
   call: AgentMessage;
@@ -119,6 +119,7 @@ export const DefaultToolBubble: React.FC<DefaultToolBubbleProps> = ({
               fontWeight: isPending ? 600 : 500,
               flexShrink: 0,
               transition: 'color 0.25s ease',
+              ...(isPending ? shimmerTextSx(c.accent.primary) : {}),
             }}
           >
             {(() => {
@@ -197,18 +198,14 @@ export const DefaultToolBubble: React.FC<DefaultToolBubbleProps> = ({
 
           {canToggleDetails && (
             <IconButton size="small" sx={{ color: c.text.tertiary, p: mcpCompact ? 0.15 : 0.25, flexShrink: 0, opacity: showBody ? 1 : 0, transition: 'opacity 120ms', '.osw-tool-row:hover &': { opacity: 1 } }}>
-              {showBody ? (
-                <ExpandLessIcon sx={{ fontSize: mcpCompact ? 16 : 18 }} />
-              ) : (
-                <ExpandMoreIcon sx={{ fontSize: mcpCompact ? 16 : 18 }} />
-              )}
+              <ExpandMoreIcon sx={{ fontSize: mcpCompact ? 16 : 18, ...chevronSx(showBody) }} />
             </IconButton>
           )}
         </Box>
 
-        <Collapse in={showBody && canToggleDetails}>
+        <Collapse in={showBody && canToggleDetails} timeout={COLLAPSE_MS} easing={COLLAPSE_EASE}>
         {/* Standalone rows hang their output off the indent rail; compact rows already sit inside the group's rail. */}
-        <Box sx={mcpCompact ? {} : { borderLeft: `2px solid ${c.border.medium}`, ml: 0.8, pl: 0.75, my: 0.25 }}>
+        <Box sx={mcpCompact ? { ...railEnterSx(showBody) } : { borderLeft: `2px solid ${c.border.medium}`, ml: 0.8, pl: 0.75, my: 0.25, ...railEnterSx(showBody) }}>
           {richRender ? (
             <Box sx={{ p: 1, bgcolor: tc.TERM_BG, borderRadius: 1.5, position: 'relative', '&:hover .osw-widget-copy': { opacity: 1 } }}>
               <WidgetCopyChip component={richRender.name} props={richRender.props} containerRef={richWidgetRef} />
diff --git a/frontend/src/app/pages/AgentChat/tool-bubbles/ToolGroupBubble.tsx b/frontend/src/app/pages/AgentChat/tool-bubbles/ToolGroupBubble.tsx
index d7762529..f5baa1a8 100644
--- a/frontend/src/app/pages/AgentChat/tool-bubbles/ToolGroupBubble.tsx
+++ b/frontend/src/app/pages/AgentChat/tool-bubbles/ToolGroupBubble.tsx
@@ -4,11 +4,11 @@ import Typography from '@mui/material/Typography';
 import Collapse from '@mui/material/Collapse';
 import IconButton from '@mui/material/IconButton';
 import ExpandMoreIcon from '@mui/icons-material/ExpandMore';
-import ExpandLessIcon from '@mui/icons-material/ExpandLess';
 import TerminalIcon from '@mui/icons-material/Terminal';
 import CheckIcon from '@mui/icons-material/Check';
 import CircularProgress from '@mui/material/CircularProgress';
 import { summarizeToolGroup } from './summarizeToolGroup';
+import { COLLAPSE_MS, COLLAPSE_EASE, chevronSx, shimmerTextSx, railEnterSx, pressSx } from './toolRowMotion';
 import { AgentMessage, ToolGroupMeta } from '@/shared/state/agentsSlice';
 import { useClaudeTokens } from '@/shared/styles/ThemeContext';
 import { useMountReveal } from './useMountReveal';
@@ -159,11 +159,12 @@ const ToolGroupBubble: React.FC<Props> = React.memo(({ group, isSessionRunning =
               cursor: 'pointer',
               color: c.text.tertiary,
               '&:hover': { color: c.text.secondary },
+              ...pressSx,
             }}
           >
             {!allDone && <CircularProgress size={12} thickness={5} sx={{ color: c.accent.primary, flexShrink: 0 }} />}
             {webDomains && webDomains.length > 0 && <SourceFavicons domains={webDomains} size={16} />}
-            <Typography sx={{ fontSize: '0.8125rem', fontWeight: 500, color: 'inherit' }}>
+            <Typography sx={{ fontSize: '0.8125rem', fontWeight: 500, color: 'inherit', ...(allDone ? {} : shimmerTextSx(c.accent.primary)) }}>
               {allDone ? (restingLabel ?? summarizeToolGroup(toolNames) ?? `Ran ${group.callCount} step${group.callCount === 1 ? '' : 's'}`) : (restingLabel ?? 'Working')}
             </Typography>
             {!allDone && group.callCount > 1 && (
@@ -181,7 +182,7 @@ const ToolGroupBubble: React.FC<Props> = React.memo(({ group, isSessionRunning =
                 {deniedCount} denied
               </Typography>
             )}
-            <ExpandMoreIcon sx={{ fontSize: 15, transform: 'rotate(-90deg)' }} />
+            <ExpandMoreIcon sx={{ fontSize: 15, ...chevronSx(false) }} />
           </Box>
         ) : (
         <Box
@@ -193,6 +194,7 @@ const ToolGroupBubble: React.FC<Props> = React.memo(({ group, isSessionRunning =
             py: 0.4,
             cursor: 'pointer',
             '&:hover': { opacity: 0.85 },
+            ...pressSx,
           }}
         >
           {!allDone ? (
@@ -219,6 +221,7 @@ const ToolGroupBubble: React.FC<Props> = React.memo(({ group, isSessionRunning =
                 fontWeight: 600,
                 flex: 1,
                 transition: 'color 200ms ease',
+                ...(allDone ? {} : shimmerTextSx(c.accent.primary)),
               }}
             >
               {displayName}
@@ -237,12 +240,12 @@ const ToolGroupBubble: React.FC<Props> = React.memo(({ group, isSessionRunning =
             </Typography>
           )}
           <IconButton size="small" sx={{ color: c.text.tertiary, p: 0.15 }}>
-            <ExpandLessIcon sx={{ fontSize: 16 }} />
+            <ExpandMoreIcon sx={{ fontSize: 16, ...chevronSx(true) }} />
           </IconButton>
         </Box>
         )}
 
-        <Collapse in={expanded}>
+        <Collapse in={expanded} timeout={COLLAPSE_MS} easing={COLLAPSE_EASE}>
           <Box
             sx={{
               // ChatGPT's indent rail: detail hangs off a thin rule under the row, no enclosing box.
@@ -250,8 +253,9 @@ const ToolGroupBubble: React.FC<Props> = React.memo(({ group, isSessionRunning =
               ml: 0.8,
               pl: 0.75,
               my: 0.25,
+              ...railEnterSx(expanded),
               '& > *': {
-                animation: 'toolRowFadeIn 140ms ease-out backwards',
+                animation: `toolRowFadeIn ${COLLAPSE_MS}ms ${COLLAPSE_EASE} backwards`,
               },
               // Staggered entrance (assistant-ui's tool-group treatment): rows cascade instead of popping at once.
               '& > *:nth-of-type(2)': { animationDelay: '40ms' },
diff --git a/frontend/src/app/pages/AgentChat/tool-bubbles/toolRowMotion.ts b/frontend/src/app/pages/AgentChat/tool-bubbles/toolRowMotion.ts
new file mode 100644
index 00000000..909be423
--- /dev/null
+++ b/frontend/src/app/pages/AgentChat/tool-bubbles/toolRowMotion.ts
@@ -0,0 +1,51 @@
+// The motion vocabulary every tool disclosure shares, copied value-for-value from the best open
+// implementations: assistant-ui's 200ms cubic-bezier(0.32,0.72,0,1) height choreography with a
+// parallel fade + slide + 2px blur-in on the content, and open-webui's text shimmer
+// (110deg sweep, 1.5s cubic-bezier(0.7,0,1,0.4)) for labels of tools still running.
+
+export const COLLAPSE_MS = 200;
+export const COLLAPSE_EASE = 'cubic-bezier(0.32, 0.72, 0, 1)';
+
+// Chevron spec: ONE glyph that rotates with the panel (never an icon swap): -90deg points right at
+// rest, 0 when open, on the same duration/curve as the height so they move as a single object.
+export function chevronSx(open: boolean): Record<string, unknown> {
+  return {
+    transform: open ? 'rotate(0deg)' : 'rotate(-90deg)',
+    transition: `transform ${COLLAPSE_MS}ms ${COLLAPSE_EASE}`,
+  };
+}
+
+export function shimmerTextSx(color: string): Record<string, unknown> {
+  return {
+    WebkitTextFillColor: 'transparent',
+    background: `linear-gradient(110deg, color-mix(in srgb, ${color} 55%, transparent) 43%, ${color} 50%, color-mix(in srgb, ${color} 55%, transparent) 57%) 0 0 / 200% 100%`,
+    WebkitBackgroundClip: 'text',
+    backgroundClip: 'text',
+    animation: 'oswToolShimmer 1.5s cubic-bezier(0.7, 0, 1, 0.4) infinite',
+    '@keyframes oswToolShimmer': {
+      from: { backgroundPosition: '100% 0' },
+      to: { backgroundPosition: '-100% 0' },
+    },
+    '@media (prefers-reduced-motion: reduce)': { animation: 'none', WebkitTextFillColor: 'unset', background: 'none', color },
+  };
+}
+
+// Content entrance layered over the height animation; the 2px blur-in is the expensive-feeling detail.
+export function railEnterSx(open: boolean): Record<string, unknown> {
+  if (!open) return {};
+  return {
+    animation: `oswRailEnter ${COLLAPSE_MS}ms ${COLLAPSE_EASE}`,
+    '@keyframes oswRailEnter': {
+      from: { opacity: 0, transform: 'translateY(-4px)', filter: 'blur(2px)' },
+      to: { opacity: 1, transform: 'none', filter: 'none' },
+    },
+    '@media (prefers-reduced-motion: reduce)': { animation: 'none' },
+  };
+}
+
+// assistant-ui's free win: triggers acknowledge the press with a tiny origin-left squeeze.
+export const pressSx: Record<string, unknown> = {
+  transformOrigin: 'left center',
+  transition: 'transform 100ms ease',
+  '&:active': { transform: 'scale(0.98)' },
+};