diff --git a/ai-hub/app/api/routes/mcp.py b/ai-hub/app/api/routes/mcp.py
index 895f8e8..6f0f77c 100644
--- a/ai-hub/app/api/routes/mcp.py
+++ b/ai-hub/app/api/routes/mcp.py
@@ -180,14 +180,14 @@
         if isinstance(body, list):
             results = []
             for item in body:
-                results.append(await _handle_single(item, token, services))
+                results.append(await _handle_single(item, user_id, services))
             return JSONResponse(
                 [r for r in results if r is not None],
                 headers={"Access-Control-Allow-Origin": "*", "MCP-Protocol-Version": MCP_VERSION},
             )
 
         # Single request
-        response = await _handle_single(body, token, services)
+        response = await _handle_single(body, user_id, services)
         if response is None:  # notification — no id
             return JSONResponse(
                 None, status_code=202,
@@ -538,9 +538,12 @@
             raise ValueError("node_id and path are required.")
             
         def _execute_write():
-            orchestrator = services.orchestrator
-            res = orchestrator.assistant.write(node_id, path, content, is_dir, session_id=session_id)
-            return res
+            from app.db.session import get_db_session
+            with get_db_session() as db:
+                services.mesh_service.require_node_access(token, node_id, db)
+                orchestrator = services.orchestrator
+                res = orchestrator.assistant.write(node_id, path, content, is_dir, session_id=session_id)
+                return res
                 
         return _ok(await loop.run_in_executor(None, _execute_write))
 
@@ -555,9 +558,12 @@
             raise ValueError("node_id and path are required.")
             
         def _execute_delete():
-            orchestrator = services.orchestrator
-            res = orchestrator.assistant.rm(node_id, path, session_id=session_id)
-            return res
+            from app.db.session import get_db_session
+            with get_db_session() as db:
+                services.mesh_service.require_node_access(token, node_id, db)
+                orchestrator = services.orchestrator
+                res = orchestrator.assistant.rm(node_id, path, session_id=session_id)
+                return res
                 
         return _ok(await loop.run_in_executor(None, _execute_delete))
 
diff --git a/frontend/src/features/chat/components/ChatWindow.js b/frontend/src/features/chat/components/ChatWindow.js
index ca4dff4..30218b1 100644
--- a/frontend/src/features/chat/components/ChatWindow.js
+++ b/frontend/src/features/chat/components/ChatWindow.js
@@ -7,6 +7,7 @@
 // Individual message component
 const ChatMessage = ({ message, index, onSynthesize, featureName = "default", activePlayingId, onPlayStateChange, evaluationMetadata }) => {
   const [isReasoningExpanded, setIsReasoningExpanded] = useState(false);
+  const [isEvalExpanded, setIsEvalExpanded] = useState(false);
   const [audioUrl, setAudioUrl] = useState(null);
   const [isPlaying, setIsPlaying] = useState(false);
   const audioRef = useRef(null);
@@ -135,10 +136,12 @@
           </button>
 
           <div
-            className={`mt-2 text-xs transition-all duration-500 ease-in-out overflow-y-auto thought-panel pl-4 pr-2 py-1 custom-scrollbar ${isReasoningExpanded ? "max-h-[400px] opacity-100 mb-2" : "max-h-0 opacity-0"
+            className={`mt-2 text-xs transition-all duration-500 ease-in-out overflow-y-auto thought-panel pl-4 pr-2 py-1 custom-scrollbar ${isReasoningExpanded ? "max-h-[400px] opacity-100 mb-2 overflow-auto" : "max-h-0 opacity-0 overflow-hidden"
               } text-gray-600 dark:text-gray-400 font-light leading-relaxed markdown-preview max-w-none`}
           >
-            <ReactMarkdown remarkPlugins={[remarkGfm]}>{message.reasoning}</ReactMarkdown>
+            {isReasoningExpanded && (
+              <ReactMarkdown remarkPlugins={[remarkGfm]}>{message.reasoning}</ReactMarkdown>
+            )}
           </div>
         </div>
       )}
@@ -151,7 +154,7 @@
       {/* Per-Answer Evaluation Metadata (Area 4: Quality Rubric / Feedback / History) */}
       {!message.isUser && effectiveEval && (effectiveEval.rubric || effectiveEval.feedback || (effectiveEval.history && effectiveEval.history.length > 0)) && (
         <div className="mt-4 pt-4 border-t border-gray-100 dark:border-gray-800 animate-in fade-in slide-in-from-top-2 duration-500">
-           <details className="group/eval">
+           <details className="group/eval" onToggle={(e) => setIsEvalExpanded(e.target.open)}>
               <summary className="flex items-center cursor-pointer list-none text-[10px] font-black uppercase tracking-widest text-indigo-500 hover:text-indigo-600 dark:hover:text-indigo-400 transition-colors">
                  <div className="flex items-center gap-2">
                     <span className="group-open/eval:rotate-90 transition-transform">▶</span>
@@ -159,55 +162,59 @@
                  </div>
               </summary>
               
-              <div className="mt-4 grid grid-cols-1 md:grid-cols-2 gap-4">
-                 {/* Rubric snippet */}
-                 {effectiveEval.rubric && (
-                   <div className="flex flex-col p-4 rounded-xl bg-gray-50 dark:bg-black/40 border border-gray-100 dark:border-gray-800 shadow-sm">
-                      <div className="text-[10px] font-black text-gray-400 uppercase mb-3 flex items-center gap-2">
-                         <div className="w-1.5 h-1.5 bg-gray-300 dark:bg-gray-700 rounded-full"></div> 📝 Quality Rubric
-                      </div>
-                      <div className="text-xs text-gray-700 dark:text-gray-300 overflow-y-auto max-h-64 custom-scrollbar pr-1 leading-relaxed">
-                         <ReactMarkdown remarkPlugins={[remarkGfm]}>{effectiveEval.rubric}</ReactMarkdown>
-                      </div>
-                   </div>
-                 )}
-                 
-                 {/* Feedback snippet */}
-                 {effectiveEval.feedback && (
-                   <div className="flex flex-col p-4 rounded-xl bg-indigo-50/40 dark:bg-indigo-500/5 border border-indigo-100/50 dark:border-indigo-500/10 shadow-sm">
-                      <div className="text-[10px] font-black text-indigo-500 uppercase mb-3 flex items-center gap-2">
-                         <div className="w-1.5 h-1.5 bg-indigo-500 rounded-full animate-pulse"></div> 🤖 Co-Worker Feedback
-                      </div>
-                      <div className="text-xs text-indigo-900/80 dark:text-indigo-200/70 overflow-y-auto max-h-64 custom-scrollbar pr-1 leading-relaxed">
-                         <ReactMarkdown remarkPlugins={[remarkGfm]}>{effectiveEval.feedback}</ReactMarkdown>
-                      </div>
-                   </div>
-                 )}
-              </div>
+              {isEvalExpanded && (
+                <>
+                  <div className="mt-4 grid grid-cols-1 md:grid-cols-2 gap-4">
+                     {/* Rubric snippet */}
+                     {effectiveEval.rubric && (
+                       <div className="flex flex-col p-4 rounded-xl bg-gray-50 dark:bg-black/40 border border-gray-100 dark:border-gray-800 shadow-sm">
+                          <div className="text-[10px] font-black text-gray-400 uppercase mb-3 flex items-center gap-2">
+                             <div className="w-1.5 h-1.5 bg-gray-300 dark:bg-gray-700 rounded-full"></div> 📝 Quality Rubric
+                          </div>
+                          <div className="text-xs text-gray-700 dark:text-gray-300 overflow-y-auto max-h-64 custom-scrollbar pr-1 leading-relaxed">
+                             <ReactMarkdown remarkPlugins={[remarkGfm]}>{effectiveEval.rubric}</ReactMarkdown>
+                          </div>
+                       </div>
+                     )}
+                     
+                     {/* Feedback snippet */}
+                     {effectiveEval.feedback && (
+                       <div className="flex flex-col p-4 rounded-xl bg-indigo-50/40 dark:bg-indigo-500/5 border border-indigo-100/50 dark:border-indigo-500/10 shadow-sm">
+                          <div className="text-[10px] font-black text-indigo-500 uppercase mb-3 flex items-center gap-2">
+                             <div className="w-1.5 h-1.5 bg-indigo-500 rounded-full animate-pulse"></div> 🤖 Co-Worker Feedback
+                          </div>
+                          <div className="text-xs text-indigo-900/80 dark:text-indigo-200/70 overflow-y-auto max-h-64 custom-scrollbar pr-1 leading-relaxed">
+                             <ReactMarkdown remarkPlugins={[remarkGfm]}>{effectiveEval.feedback}</ReactMarkdown>
+                          </div>
+                       </div>
+                     )}
+                  </div>
 
-              {/* History Timeline snippet */}
-              {effectiveEval.history && effectiveEval.history.length > 0 && (
-                <div className="mt-4 p-4 rounded-xl bg-emerald-50/20 dark:bg-emerald-500/5 border border-emerald-100/30 dark:border-emerald-500/10 shadow-sm">
-                   <div className="text-[10px] font-black text-emerald-500 uppercase mb-3 flex items-center gap-2">
-                      <div className="w-1.5 h-1.5 bg-emerald-500 rounded-full"></div> 🕒 Rework History Timeline
-                   </div>
-                   <div className="flex flex-col gap-3 max-h-64 overflow-y-auto pr-2 custom-scrollbar">
-                      {effectiveEval.history.map((h, i) => (
-                        <div key={i} className="flex justify-between items-start text-xs border-l-2 border-emerald-500/20 pl-3 py-1 last:pb-0 transition-all hover:bg-emerald-500/5 rounded-r">
-                           <div className="flex flex-col gap-0.5">
-                              <span className="font-bold text-gray-800 dark:text-gray-200">
-                                {h.type === 'attempt' ? `Attempt ${h.round}` : h.name}
-                                {h.score !== undefined && <span className="ml-3 px-1.5 py-0.5 bg-emerald-500 text-white dark:text-emerald-100 rounded-md text-[10px] font-bold shadow-sm">Score: {h.score}%</span>}
-                              </span>
-                              <span className="text-gray-500 dark:text-gray-400 italic text-[11px] leading-snug">{h.reason || h.message || h.details}</span>
-                           </div>
-                           <span className="text-gray-400 dark:text-gray-600 font-mono text-[10px]">
-                              {h.timestamp ? new Date(h.timestamp * (h.timestamp < 2000000000 ? 1000 : 1)).toLocaleTimeString([], { hour: '2-digit', minute: '2-digit' }) : 'Recent'}
-                           </span>
-                        </div>
-                      ))}
-                   </div>
-                </div>
+                  {/* History Timeline snippet */}
+                  {effectiveEval.history && effectiveEval.history.length > 0 && (
+                    <div className="mt-4 p-4 rounded-xl bg-emerald-50/20 dark:bg-emerald-500/5 border border-emerald-100/30 dark:border-emerald-500/10 shadow-sm">
+                       <div className="text-[10px] font-black text-emerald-500 uppercase mb-3 flex items-center gap-2">
+                          <div className="w-1.5 h-1.5 bg-emerald-500 rounded-full"></div> 🕒 Rework History Timeline
+                       </div>
+                       <div className="flex flex-col gap-3 max-h-64 overflow-y-auto pr-2 custom-scrollbar">
+                          {effectiveEval.history.map((h, i) => (
+                            <div key={i} className="flex justify-between items-start text-xs border-l-2 border-emerald-500/20 pl-3 py-1 last:pb-0 transition-all hover:bg-emerald-500/5 rounded-r">
+                               <div className="flex flex-col gap-0.5">
+                                  <span className="font-bold text-gray-800 dark:text-gray-200">
+                                    {h.type === 'attempt' ? `Attempt ${h.round}` : h.name}
+                                    {h.score !== undefined && <span className="ml-3 px-1.5 py-0.5 bg-emerald-500 text-white dark:text-emerald-100 rounded-md text-[10px] font-bold shadow-sm">Score: {h.score}%</span>}
+                                  </span>
+                                  <span className="text-gray-500 dark:text-gray-400 italic text-[11px] leading-snug">{h.reason || h.message || h.details}</span>
+                               </div>
+                               <span className="text-gray-400 dark:text-gray-600 font-mono text-[10px]">
+                                  {h.timestamp ? new Date(h.timestamp * (h.timestamp < 2000000000 ? 1000 : 1)).toLocaleTimeString([], { hour: '2-digit', minute: '2-digit' }) : 'Recent'}
+                               </span>
+                            </div>
+                          ))}
+                       </div>
+                    </div>
+                  )}
+                </>
               )}
            </details>
         </div>