[eric] chat: assistant answers drop the bubble (user-only bubbles); tool-ui cards get skeleton + blur-in entrance

frontend/src/app/pages/AgentChat/tool-ui/ToolUiBubble.tsx

@@ -26,7 +26,22 @@ function ToolUiBubble({ pair, sessionId, isPending, suppressReveal, sessionRunni
     );
   }
   return (
-    <Box sx={{ my: 1, contain: 'layout style' }} data-select-type="tool-ui" data-select-id={pair.id} data-select-meta={JSON.stringify({ component: payload.component })}>
+    <Box
+      sx={{
+        my: 1,
+        contain: 'layout style',
+        // One-shot entrance (assistant-ui's fade + rise + blur-in): the card arrives, it doesn't pop.
+        animation: 'toolUiEnter 240ms cubic-bezier(0.32, 0.72, 0, 1)',
+        '@keyframes toolUiEnter': {
+          from: { opacity: 0, transform: 'translateY(6px)', filter: 'blur(2px)' },
+          to: { opacity: 1, transform: 'translateY(0)', filter: 'blur(0)' },
+        },
+        '@media (prefers-reduced-motion: reduce)': { animation: 'none' },
+      }}
+      data-select-type="tool-ui"
+      data-select-id={pair.id}
+      data-select-meta={JSON.stringify({ component: payload.component })}
+    >
       <ShowUiWidgetView payload={payload} />
     </Box>
   );

frontend/src/toolui/VendoredToolUi.tsx

@@ -60,6 +60,29 @@ function parseLeniently(schema: { safeParse: (v: unknown) => any }, props: Recor
   return { state: 'bad', problem: issues };
 }
 
+// Rough resting height per component family so the loading skeleton reserves believable space
+// (Lobe/Open WebUI pattern: a breathing block where the card will land, not a tiny sliver).
+function skeletonHeightFor(name: string): number {
+  if (/table|chart|gallery|map|carousel|post|terminal/.test(name)) return 180;
+  if (/stats|weather|plan|order|preferences|question/.test(name)) return 110;
+  return 56;
+}
+
+const SkeletonBlock: React.FC<{ name: string }> = ({ name }) => (
+  <div
+    style={{
+      height: skeletonHeightFor(name),
+      width: '100%',
+      maxWidth: 520,
+      borderRadius: 12,
+      background: 'rgba(127,127,127,0.12)',
+      animation: 'toolui-skeleton-pulse 1.4s ease-in-out infinite',
+    }}
+  >
+    <style>{'@keyframes toolui-skeleton-pulse { 0%, 100% { opacity: 0.55; } 50% { opacity: 1; } }'}</style>
+  </div>
+);
+
 /** Validates against the upstream zod contract, then renders the vendored component inside the scoped theme. */
 function VendoredToolUi({ name, props, extraProps }: VendoredToolUiProps): React.ReactElement | null {
   const { mode } = useThemeMode();
@@ -87,13 +110,13 @@ function VendoredToolUi({ name, props, extraProps }: VendoredToolUiProps): React
     );
   }
   if (gate.state === 'pending') {
-    return <div style={{ height: 48, width: 280, borderRadius: 12, background: 'rgba(127,127,127,0.12)' }} />;
+    return <SkeletonBlock name={name} />;
   }
   const Component = entry.Component;
   return (
     <div className={`tool-ui-scope${mode === 'dark' ? ' dark' : ''}`}>
       <ComponentGuard name={name}>
-        <Suspense fallback={<div style={{ height: 48, width: 280, borderRadius: 12, background: 'rgba(127,127,127,0.12)' }} />}>
+        <Suspense fallback={<SkeletonBlock name={name} />}>
           <Component {...gate.parsed} {...(extraProps || {})} />
         </Suspense>
       </ComponentGuard>