diff --git a/frontend/src/App.tsx b/frontend/src/App.tsx
index fb5dd5f..99bdf0a 100644
--- a/frontend/src/App.tsx
+++ b/frontend/src/App.tsx
@@ -31,7 +31,6 @@ function App() {
         onSelect={(id) => switchTo(id)}
         onCreate={async () => {
           await createNew()
-          await refresh()
         }}
         onLogout={logout}
       />
diff --git a/frontend/src/components/ChatPanel.tsx b/frontend/src/components/ChatPanel.tsx
index d44d597..16e256e 100644
--- a/frontend/src/components/ChatPanel.tsx
+++ b/frontend/src/components/ChatPanel.tsx
@@ -58,7 +58,7 @@ export function ChatPanel({ messages, isStreaming, onSend, sessionId }: ChatPane
     <div className='chat-panel'>
       <div className='chat-messages'>
         {messages.map(message => (
-          <div key={message.id}>
+          <div key={message.id} className={`chat-message ${message.role}`}>
             {message.role === 'assistant' ? (
               <div>
                 <ReactMarkdown>{message.content}</ReactMarkdown>
diff --git a/frontend/src/components/LoginPage.tsx b/frontend/src/components/LoginPage.tsx
index a5ea3c9..a5d38a3 100644
--- a/frontend/src/components/LoginPage.tsx
+++ b/frontend/src/components/LoginPage.tsx
@@ -28,7 +28,7 @@ export function LoginPage({ onLogin }: LoginPageProps) {
     <div className="login-page">
       <form className="login-card" onSubmit={handleSubmit}>
         <h2>Research Workbench</h2>
-        {error && <div className="login-error">{error}</div>}
+        {error && <div className="error">{error}</div>}
         <label htmlFor="email">Email</label>
         <input
           id="email"
diff --git a/frontend/src/components/MCPAppRenderer.tsx b/frontend/src/components/MCPAppRenderer.tsx
index d6fee2e..0708b66 100644
--- a/frontend/src/components/MCPAppRenderer.tsx
+++ b/frontend/src/components/MCPAppRenderer.tsx
@@ -53,6 +53,7 @@ export function MCPAppRenderer({
   const handleMessage = useCallback(
     (event: MessageEvent) => {
       if (!iframeRef.current?.contentWindow) return
+      if (event.source !== iframeRef.current.contentWindow) return
 
       const msg = event.data
       if (!msg || msg.jsonrpc !== '2.0') return
diff --git a/frontend/src/hooks/useArtifacts.ts b/frontend/src/hooks/useArtifacts.ts
index 10f8fcf..b7dac7d 100644
--- a/frontend/src/hooks/useArtifacts.ts
+++ b/frontend/src/hooks/useArtifacts.ts
@@ -8,8 +8,12 @@ export function useArtifacts(sessionId: string | null) {
 
   async function refresh() {
     if (!sessionId) return
-    const data = await api.listArtifacts(sessionId)
-    setArtifacts(data)
+    try {
+      const data = await api.listArtifacts(sessionId)
+      setArtifacts(data)
+    } catch (err) {
+      console.error('Failed to list artifacts:', err)
+    }
   }
 
   async function loadArtifact(name: string) {