diff --git a/packages/ui/src/components/chat/multi-task-chat.tsx b/packages/ui/src/components/chat/multi-task-chat.tsx
index e2f5eb1..188a699 100644
--- a/packages/ui/src/components/chat/multi-task-chat.tsx
+++ b/packages/ui/src/components/chat/multi-task-chat.tsx
@@ -634,28 +634,54 @@ export default function MultiTaskChat(props: MultiTaskChatProps) {
           </div>
         </div>
 
-        {/* Message Navigation Sidebar - YOU/ASST labels */}
+        {/* Message Navigation Sidebar - YOU/ASST labels with hover preview */}
         <Show when={selectedTaskId() && filteredMessageIds().length > 0}>
-          <div class="w-12 shrink-0 bg-zinc-900/40 border-l border-white/5 overflow-y-auto py-2 px-1 flex flex-col items-center gap-1">
+          <div class="w-14 shrink-0 bg-zinc-900/40 border-l border-white/5 overflow-y-auto py-2 px-1.5 flex flex-col items-center gap-1">
             <For each={filteredMessageIds()}>
               {(messageId, index) => {
                 const msg = () => messageStore().getMessage(messageId);
                 const isUser = () => msg()?.role === "user";
+                const [showPreview, setShowPreview] = createSignal(false);
+
+                // Get message preview text (first 100 chars)
+                const previewText = () => {
+                  const message = msg();
+                  if (!message) return "";
+                  const content = message.parts?.[0]?.content || message.content || "";
+                  const text = typeof content === "string" ? content : JSON.stringify(content);
+                  return text.length > 100 ? text.substring(0, 100) + "..." : text;
+                };
+
                 return (
-                  <button
-                    onClick={() => {
-                      // Scroll to message
-                      const element = document.getElementById(`msg-${messageId}`);
-                      element?.scrollIntoView({ behavior: "smooth", block: "center" });
-                    }}
-                    class={`w-9 py-1 rounded text-[8px] font-black uppercase transition-all ${isUser()
-                      ? "bg-indigo-500/20 border border-indigo-500/40 text-indigo-400 hover:bg-indigo-500/30"
-                      : "bg-emerald-500/20 border border-emerald-500/40 text-emerald-400 hover:bg-emerald-500/30"
-                      }`}
-                    title={`${isUser() ? "User" : "Assistant"} message ${index() + 1}`}
-                  >
-                    {isUser() ? "YOU" : "ASST"}
-                  </button>
+                  <div class="relative group">
+                    <button
+                      onClick={() => {
+                        // Scroll to message
+                        const element = document.getElementById(`msg-${messageId}`);
+                        element?.scrollIntoView({ behavior: "smooth", block: "center" });
+                      }}
+                      onMouseEnter={() => setShowPreview(true)}
+                      onMouseLeave={() => setShowPreview(false)}
+                      class={`w-10 py-1.5 rounded text-[8px] font-black uppercase transition-all cursor-pointer ${isUser()
+                        ? "bg-indigo-500/20 border border-indigo-500/40 text-indigo-400 hover:bg-indigo-500/40 hover:scale-105"
+                        : "bg-emerald-500/20 border border-emerald-500/40 text-emerald-400 hover:bg-emerald-500/40 hover:scale-105"
+                        }`}
+                    >
+                      {isUser() ? "YOU" : "ASST"}
+                    </button>
+
+                    {/* Hover Preview Tooltip */}
+                    <Show when={showPreview()}>
+                      <div class="absolute right-full mr-2 top-0 w-64 max-h-32 overflow-hidden bg-zinc-900 border border-white/10 rounded-lg shadow-xl p-2 z-50 animate-in fade-in slide-in-from-right-2 duration-150">
+                        <div class={`text-[9px] font-bold uppercase mb-1 ${isUser() ? "text-indigo-400" : "text-emerald-400"}`}>
+                          {isUser() ? "You" : "Assistant"} • Message {index() + 1}
+                        </div>
+                        <p class="text-[11px] text-zinc-300 leading-relaxed line-clamp-4">
+                          {previewText()}
+                        </p>
+                      </div>
+                    </Show>
+                  </div>
                 );
               }}
             </For>