files cant't be seen by LLM, but everything else works.

frontend/src/components/chat/ChatArea.tsx

@@ -105,7 +105,8 @@ export default function ChatArea({ conversationId }: ChatAreaProps) {
           settings.temperature,
           settings.maxTokens,
           systemPrompt,
-          abortControllerRef.current.signal
+          abortControllerRef.current.signal,
+          conversationId
         );
 
         for await (const chunk of stream) {

frontend/src/components/chat/SettingsModal.tsx

@@ -1,10 +1,12 @@
 import { useState, useEffect } from 'react';
-import { X, RefreshCw, Eye, EyeOff } from 'lucide-react';
+import { X, RefreshCw, Eye, EyeOff, BarChart3 } from 'lucide-react';
 import { useChatStore } from '@/stores/chatStore';
 import { fetchModels } from '@/services/api';
+import TokenUsagePanel from './TokenUsagePanel';
 
 export default function SettingsModal() {
   const { settings, updateSettings, toggleSettings, closeSettings } = useChatStore();
+  const [activeTab, setActiveTab] = useState<'settings' | 'tokens'>('settings');
   const [localSettings, setLocalSettings] = useState(settings);
   const [models, setModels] = useState<string[]>([]);
   const [isLoadingModels, setIsLoadingModels] = useState(false);
@@ -52,20 +54,51 @@ export default function SettingsModal() {
         className="absolute inset-0 bg-black/60 backdrop-blur-sm"
         onClick={toggleSettings}
       />
-      <div className="relative bg-[var(--color-surface)] border border-[var(--color-border)] rounded-2xl w-full max-w-lg max-h-[90vh] overflow-y-auto shadow-2xl">
+      <div className="relative bg-[var(--color-surface)] border border-[var(--color-border)] rounded-2xl w-full max-w-lg max-h-[90vh] overflow-y-auto shadow-2xl flex flex-col">
         {/* Header */}
-        <div className="flex items-center justify-between p-6 border-b border-[var(--color-border)]">
-          <h2 className="text-xl font-semibold text-[var(--color-text)]">Settings</h2>
-          <button
-            onClick={toggleSettings}
-            className="p-2 rounded-lg hover:bg-[var(--color-surface-hover)] text-[var(--color-text-secondary)] hover:text-[var(--color-text)] transition-colors"
-          >
-            <X size={20} />
-          </button>
+        <div className="flex-shrink-0">
+          <div className="flex items-center justify-between p-6 border-b border-[var(--color-border)]">
+            <h2 className="text-xl font-semibold text-[var(--color-text)]">Settings</h2>
+            <button
+              onClick={toggleSettings}
+              className="p-2 rounded-lg hover:bg-[var(--color-surface-hover)] text-[var(--color-text-secondary)] hover:text-[var(--color-text)] transition-colors"
+            >
+              <X size={20} />
+            </button>
+          </div>
+
+          {/* Tabs */}
+          <div className="flex gap-1 px-6 pb-2">
+            <button
+              onClick={() => setActiveTab('settings')}
+              className={`flex-1 px-4 py-2 rounded-t-lg text-sm font-medium transition-colors ${
+                activeTab === 'settings'
+                  ? 'bg-[var(--color-bg)] text-[var(--color-text)] border-t-2 border-[var(--color-accent)]'
+                  : 'text-[var(--color-text-muted)] hover:text-[var(--color-text)]'
+              }`}
+            >
+              Configuration
+            </button>
+            <button
+              onClick={() => setActiveTab('tokens')}
+              className={`flex-1 px-4 py-2 rounded-t-lg text-sm font-medium transition-colors ${
+                activeTab === 'tokens'
+                  ? 'bg-[var(--color-bg)] text-[var(--color-text)] border-t-2 border-[var(--color-accent)]'
+                  : 'text-[var(--color-text-muted)] hover:text-[var(--color-text)]'
+              }`}
+            >
+              <div className="flex items-center justify-center gap-1.5">
+                <BarChart3 size={14} />
+                <span>Token Usage</span>
+              </div>
+            </button>
+          </div>
         </div>
 
         {/* Content */}
-        <div className="p-6 space-y-5">
+        <div className="flex-1 overflow-y-auto">
+          {activeTab === 'settings' ? (
+            <div className="p-6 space-y-5">
           {error && (
             <div className="p-3 rounded-lg bg-red-500/10 border border-red-500/20 text-red-400 text-sm">
               {error}
@@ -217,59 +250,67 @@ export default function SettingsModal() {
             />
           </div>
 
-          <hr className="border-[var(--color-border)]" />
+              <hr className="border-[var(--color-border)]" />
 
-          {/* Embedding Model */}
-          <div className="space-y-2">
-            <label className="text-sm font-medium text-[var(--color-text-secondary)]">
-              Embedding Model
-            </label>
-            <input
-              type="text"
-              value={localSettings.embeddingModel}
-              onChange={(e) =>
-                setLocalSettings((prev) => ({ ...prev, embeddingModel: e.target.value }))
-              }
-              placeholder="text-embedding-3-small"
-              className="input-field"
-            />
-            <p className="text-xs text-[var(--color-text-muted)]">
-              Model used for knowledge base embeddings
-            </p>
-          </div>
+              {/* Embedding Model */}
+              <div className="space-y-2">
+                <label className="text-sm font-medium text-[var(--color-text-secondary)]">
+                  Embedding Model
+                </label>
+                <input
+                  type="text"
+                  value={localSettings.embeddingModel}
+                  onChange={(e) =>
+                    setLocalSettings((prev) => ({ ...prev, embeddingModel: e.target.value }))
+                  }
+                  placeholder="text-embedding-3-small"
+                  className="input-field"
+                />
+                <p className="text-xs text-[var(--color-text-muted)]">
+                  Model used for knowledge base embeddings
+                </p>
+              </div>
 
-          {/* ChromaDB Directory */}
-          <div className="space-y-2">
-            <label className="text-sm font-medium text-[var(--color-text-secondary)]">
-              ChromaDB Directory
-            </label>
-            <input
-              type="text"
-              value={localSettings.chromaDir}
-              onChange={(e) =>
-                setLocalSettings((prev) => ({ ...prev, chromaDir: e.target.value }))
-              }
-              placeholder="./data/chromadb"
-              className="input-field"
-            />
-            <p className="text-xs text-[var(--color-text-muted)]">
-              Path to ChromaDB persistent storage on the server
-            </p>
-          </div>
+              {/* ChromaDB Directory */}
+              <div className="space-y-2">
+                <label className="text-sm font-medium text-[var(--color-text-secondary)]">
+                  ChromaDB Directory
+                </label>
+                <input
+                  type="text"
+                  value={localSettings.chromaDir}
+                  onChange={(e) =>
+                    setLocalSettings((prev) => ({ ...prev, chromaDir: e.target.value }))
+                  }
+                  placeholder="./data/chromadb"
+                  className="input-field"
+                />
+                <p className="text-xs text-[var(--color-text-muted)]">
+                  Path to ChromaDB persistent storage on the server
+                </p>
+              </div>
+            </div>
+          ) : (
+            <div className="p-6">
+              <TokenUsagePanel />
+            </div>
+          )}
         </div>
 
         {/* Footer */}
-        <div className="flex items-center justify-end gap-3 p-6 border-t border-[var(--color-border)]">
-          <button
-            onClick={toggleSettings}
-            className="px-4 py-2 rounded-lg text-[var(--color-text-secondary)] hover:text-[var(--color-text)] hover:bg-[var(--color-surface-hover)] transition-colors"
-          >
-            Cancel
-          </button>
-          <button onClick={handleSave} className="btn-primary">
-            Save Settings
-          </button>
-        </div>
+        {activeTab === 'settings' && (
+          <div className="flex items-center justify-end gap-3 p-6 border-t border-[var(--color-border)] shrink-0">
+            <button
+              onClick={toggleSettings}
+              className="px-4 py-2 rounded-lg text-[var(--color-text-secondary)] hover:text-[var(--color-text)] hover:bg-[var(--color-surface-hover)] transition-colors"
+            >
+              Cancel
+            </button>
+            <button onClick={handleSave} className="btn-primary">
+              Save Settings
+            </button>
+          </div>
+        )}
       </div>
     </div>
   );

frontend/src/components/chat/TokenUsagePanel.tsx

@@ -0,0 +1,282 @@
+import { useState, useEffect } from 'react';
+import { RefreshCw, Trash2, BarChart3 } from 'lucide-react';
+
+interface TokenUsageSummary {
+  promptTokens: number;
+  completionTokens: number;
+  totalTokens: number;
+  requestCount: number;
+}
+
+interface ModelBreakdown {
+  [key: string]: {
+    promptTokens: number;
+    completionTokens: number;
+    totalTokens: number;
+    requestCount: number;
+  };
+}
+
+interface TokenUsageHistory {
+  timestamp: number;
+  conversationId: string;
+  model: string;
+  promptTokens: number;
+  completionTokens: number;
+  totalTokens: number;
+}
+
+interface TokenUsageData {
+  summary: TokenUsageSummary;
+  modelBreakdown: ModelBreakdown;
+  history: TokenUsageHistory[];
+}
+
+type TimePeriod = 'all' | 'today' | 'week';
+
+export default function TokenUsagePanel() {
+  const [data, setData] = useState<TokenUsageData | null>(null);
+  const [loading, setLoading] = useState(false);
+  const [period, setPeriod] = useState<TimePeriod>('all');
+  const [expandedModel, setExpandedModel] = useState<string | null>(null);
+
+  const fetchData = async () => {
+    setLoading(true);
+    try {
+      const res = await fetch(`/api/token-usage?period=${period}`);
+      const result = await res.json();
+      setData(result);
+    } catch (err) {
+      console.error('Failed to fetch token usage:', err);
+    } finally {
+      setLoading(false);
+    }
+  };
+
+  useEffect(() => {
+    fetchData();
+  }, [period]);
+
+  const handleClear = async () => {
+    if (!confirm('Clear all token usage data?')) return;
+    try {
+      await fetch('/api/token-usage', { method: 'DELETE' });
+      setData(null);
+      fetchData();
+    } catch (err) {
+      console.error('Failed to clear token usage:', err);
+    }
+  };
+
+  const formatNumber = (n: number) => n.toLocaleString();
+
+  const formatTime = (timestamp: number) => {
+    const date = new Date(timestamp);
+    return date.toLocaleTimeString('ru-RU', { hour: '2-digit', minute: '2-digit' });
+  };
+
+  return (
+    <div className="space-y-4">
+      {/* Header */}
+      <div className="flex items-center justify-between">
+        <div className="flex items-center gap-2 text-[var(--color-text)]">
+          <BarChart3 size={20} className="text-[var(--color-accent)]" />
+          <h3 className="text-sm font-medium">Token Usage</h3>
+        </div>
+        <div className="flex items-center gap-2">
+          <button
+            onClick={fetchData}
+            disabled={loading}
+            className="p-2 rounded-lg hover:bg-[var(--color-surface-hover)] text-[var(--color-text-secondary)] hover:text-[var(--color-text)] transition-colors disabled:opacity-50"
+          >
+            <RefreshCw size={16} className={loading ? 'animate-spin' : ''} />
+          </button>
+          <button
+            onClick={handleClear}
+            disabled={!data || data.summary.requestCount === 0}
+            className="p-2 rounded-lg hover:bg-[var(--color-surface-hover)] text-[var(--color-text-secondary)] hover:text-red-400 transition-colors disabled:opacity-50 disabled:pointer-events-none"
+          >
+            <Trash2 size={16} />
+          </button>
+        </div>
+      </div>
+
+      {/* Period filter */}
+      <div className="flex gap-1 p-1 rounded-lg bg-[var(--color-bg)] border border-[var(--color-border)]">
+        {(['all', 'today', 'week'] as TimePeriod[]).map((p) => {
+          const labels = { all: 'All', today: 'Today', week: 'Week' };
+          return (
+            <button
+              key={p}
+              onClick={() => setPeriod(p)}
+              className={`flex-1 px-3 py-1.5 rounded-md text-xs font-medium transition-colors ${
+                period === p
+                  ? 'bg-[var(--color-accent)] text-white'
+                  : 'text-[var(--color-text-muted)] hover:text-[var(--color-text)]'
+              }`}
+            >
+              {labels[p]}
+            </button>
+          );
+        })}
+      </div>
+
+      {/* Summary */}
+      {data && data.summary.requestCount > 0 ? (
+        <div className="grid grid-cols-2 gap-3">
+          <div className="p-3 rounded-lg bg-[var(--color-bg)] border border-[var(--color-border)]">
+            <p className="text-xs text-[var(--color-text-muted)] mb-1">Total Tokens</p>
+            <p className="text-lg font-semibold text-[var(--color-text)]">
+              {formatNumber(data.summary.totalTokens)}
+            </p>
+          </div>
+          <div className="p-3 rounded-lg bg-[var(--color-bg)] border border-[var(--color-border)]">
+            <p className="text-xs text-[var(--color-text-muted)] mb-1">Requests</p>
+            <p className="text-lg font-semibold text-[var(--color-text)]">
+              {data.summary.requestCount}
+            </p>
+          </div>
+          <div className="p-3 rounded-lg bg-[var(--color-bg)] border border-[var(--color-border)]">
+            <p className="text-xs text-[var(--color-text-muted)] mb-1">Prompt Tokens</p>
+            <p className="text-sm font-medium text-[var(--color-text)]">
+              {formatNumber(data.summary.promptTokens)}
+            </p>
+          </div>
+          <div className="p-3 rounded-lg bg-[var(--color-bg)] border border-[var(--color-border)]">
+            <p className="text-xs text-[var(--color-text-muted)] mb-1">Completion Tokens</p>
+            <p className="text-sm font-medium text-[var(--color-text)]">
+              {formatNumber(data.summary.completionTokens)}
+            </p>
+          </div>
+        </div>
+      ) : (
+        <div className="text-center py-8 text-[var(--color-text-muted)]">
+          {loading ? 'Loading...' : 'No token usage data yet'}
+        </div>
+      )}
+
+      {/* Model breakdown */}
+      {data && Object.keys(data.modelBreakdown).length > 0 && (
+        <div className="space-y-2">
+          <p className="text-sm font-medium text-[var(--color-text)]">By Model</p>
+          {Object.entries(data.modelBreakdown)
+            .sort((a, b) => b[1].totalTokens - a[1].totalTokens)
+            .map(([model, stats]) => (
+              <div
+                key={model}
+                className="rounded-lg border border-[var(--color-border)] bg-[var(--color-bg)] overflow-hidden"
+              >
+                <button
+                  onClick={() => setExpandedModel(expandedModel === model ? null : model)}
+                  className="w-full px-4 py-3 flex items-center justify-between text-left hover:bg-[var(--color-surface-hover)] transition-colors"
+                >
+                  <div className="min-w-0">
+                    <p className="text-sm font-medium text-[var(--color-text)] truncate">
+                      {model}
+                    </p>
+                    <p className="text-xs text-[var(--color-text-muted)]">
+                      {formatNumber(stats.totalTokens)} tokens · {stats.requestCount} requests
+                    </p>
+                  </div>
+                  <div className="text-right shrink-0 ml-4">
+                    <p className="text-xs text-[var(--color-text-secondary)]">
+                      {formatNumber(stats.promptTokens)} / {formatNumber(stats.completionTokens)}
+                    </p>
+                  </div>
+                </button>
+
+                {expandedModel === model && (
+                  <div className="px-4 pb-3 border-t border-[var(--color-border)] pt-3">
+                    {/* Simple bar chart */}
+                    <div className="space-y-2">
+                      <div className="flex items-center gap-2">
+                        <span className="text-xs text-[var(--color-text-muted)] w-16">Prompt</span>
+                        <div className="flex-1 h-3 rounded bg-[var(--color-surface)] overflow-hidden">
+                          <div
+                            className="h-full rounded bg-[var(--color-accent)] transition-all"
+                            style={{
+                              width: `${
+                                stats.totalTokens > 0
+                                  ? (stats.promptTokens / stats.totalTokens) * 100
+                                  : 0
+                              }%`,
+                            }}
+                          />
+                        </div>
+                        <span className="text-xs text-[var(--color-text)] w-16 text-right">
+                          {formatNumber(stats.promptTokens)}
+                        </span>
+                      </div>
+                      <div className="flex items-center gap-2">
+                        <span className="text-xs text-[var(--color-text-muted)] w-16">Completion</span>
+                        <div className="flex-1 h-3 rounded bg-[var(--color-surface)] overflow-hidden">
+                          <div
+                            className="h-full rounded bg-green-500 transition-all"
+                            style={{
+                              width: `${
+                                stats.totalTokens > 0
+                                  ? (stats.completionTokens / stats.totalTokens) * 100
+                                  : 0
+                              }%`,
+                            }}
+                          />
+                        </div>
+                        <span className="text-xs text-[var(--color-text)] w-16 text-right">
+                          {formatNumber(stats.completionTokens)}
+                        </span>
+                      </div>
+                    </div>
+
+                    {/* Show recent history for this model */}
+                    {data.history.filter((h) => h.model === model).length > 0 && (
+                      <div className="mt-3 pt-3 border-t border-[var(--color-border)]">
+                        <p className="text-xs text-[var(--color-text-muted)] mb-2">Recent requests</p>
+                        <div className="space-y-1 max-h-32 overflow-y-auto">
+                          {data.history
+                            .filter((h) => h.model === model)
+                            .slice(-5)
+                            .reverse()
+                            .map((entry, i) => (
+                              <div
+                                key={i}
+                                className="flex items-center justify-between text-xs px-2 py-1 rounded bg-[var(--color-surface)]"
+                              >
+                                <span className="text-[var(--color-text-muted)]">{formatTime(entry.timestamp)}</span>
+                                <span className="text-[var(--color-text)]">
+                                  {formatNumber(entry.totalTokens)} tokens
+                                </span>
+                              </div>
+                            ))}
+                        </div>
+                      </div>
+                    )}
+                  </div>
+                )}
+              </div>
+            ))}
+        </div>
+      )}
+
+      {/* History timeline */}
+      {data && data.history.length > 0 && (
+        <div className="space-y-2">
+          <p className="text-sm font-medium text-[var(--color-text)]">Recent History</p>
+          {data.history.slice(-10).reverse().map((entry, i) => (
+            <div
+              key={i}
+              className="flex items-center gap-3 text-xs px-3 py-2 rounded-lg bg-[var(--color-bg)] border border-[var(--color-border)]"
+            >
+              <span className="text-[var(--color-text-muted)] w-12 shrink-0">
+                {formatTime(entry.timestamp)}
+              </span>
+              <span className="text-[var(--color-text)] truncate flex-1">{entry.model}</span>
+              <span className="text-[var(--color-text-secondary)] shrink-0">
+                {formatNumber(entry.totalTokens)}
+              </span>
+            </div>
+          ))}
+        </div>
+      )}
+    </div>
+  );
+}

frontend/src/components/knowledge/KnowledgePanel.tsx

@@ -1,7 +1,15 @@
-import { useState, useEffect } from 'react';
-import { X, Plus, Trash2, Upload, BookOpen, FileText, Database, ChevronDown, ChevronUp } from 'lucide-react';
+import { useState, useEffect, useRef } from 'react';
+import { X, Plus, Trash2, Upload, BookOpen, FileText, Database, ChevronDown, ChevronUp, FolderOpen, AlertCircle } from 'lucide-react';
 import { useChatStore } from '@/stores/chatStore';
 
+interface FileResult {
+  id: string;
+  originalName: string;
+  size: number;
+  chunkCount?: number;
+}
+
+
 export default function KnowledgePanel() {
   const { settings, toggleKnowledge, isKnowledgeOpen, setKnowledgeBases, knowledgeBases, removeKnowledgeBase } = useChatStore();
   const [newName, setNewName] = useState('');
@@ -10,6 +18,10 @@ export default function KnowledgePanel() {
   const [expandedBase, setExpandedBase] = useState<string | null>(null);
   const [uploadingBase, setUploadingBase] = useState<string | null>(null);
   const [loading, setLoading] = useState(false);
+  const [folderLoading, setFolderLoading] = useState(false);
+  const [error, setError] = useState<string | null>(null);
+  const fileInputRef = useRef<HTMLInputElement>(null);
+  const folderInputRef = useRef<HTMLInputElement>(null);
 
   useEffect(() => {
     if (isKnowledgeOpen) loadBases();
@@ -17,11 +29,15 @@ export default function KnowledgePanel() {
 
   const loadBases = async () => {
     try {
+      setError(null);
       const res = await fetch('/api/knowledge');
+      if (!res.ok) throw new Error('Failed to load');
       const data = await res.json();
       setKnowledgeBases(data.bases || []);
     } catch (err) {
       console.error('Failed to load knowledge bases:', err);
+      setError('Could not connect to knowledge base service. Is the backend running?');
+      setKnowledgeBases([]);
     }
   };
 
@@ -35,12 +51,13 @@ export default function KnowledgePanel() {
         body: JSON.stringify({ name: newName.trim(), description: newDesc.trim() }),
       });
       const base = await res.json();
+      if (base.error) throw new Error(base.error);
       setKnowledgeBases([...knowledgeBases, base]);
       setNewName('');
       setNewDesc('');
       setIsCreating(false);
-    } catch (err) {
-      alert('Failed to create knowledge base');
+    } catch (err: any) {
+      setError(err.message || 'Failed to create knowledge base');
     } finally {
       setLoading(false);
     }
@@ -52,7 +69,7 @@ export default function KnowledgePanel() {
       await fetch(`/api/knowledge/${id}`, { method: 'DELETE' });
       removeKnowledgeBase(id);
     } catch (err) {
-      alert('Failed to delete knowledge base');
+      setError('Failed to delete knowledge base');
     }
   };
 
@@ -60,6 +77,7 @@ export default function KnowledgePanel() {
     if (!e.target.files?.[0]) return;
     const file = e.target.files[0];
     setUploadingBase(baseId);
+    setError(null);
 
     try {
       const formData = new FormData();
@@ -76,7 +94,6 @@ export default function KnowledgePanel() {
       if (!res.ok) throw new Error('Upload failed');
       const data = await res.json();
 
-      // Update local state
       const updated = knowledgeBases.map((b) =>
         b.id === baseId
           ? { ...b, files: [...b.files, data.file], documentCount: (b.documentCount || 0) + data.chunks }
@@ -84,13 +101,68 @@ export default function KnowledgePanel() {
       );
       setKnowledgeBases(updated);
     } catch (err) {
-      alert('Failed to upload file. Make sure API settings are configured.');
+      setError('Failed to upload file. Make sure API settings are configured.');
     } finally {
       setUploadingBase(null);
       e.target.value = '';
     }
   };
 
+  const handleUploadFolder = async (baseId: string, e: React.ChangeEvent<HTMLInputElement>) => {
+    const files = e.target.files;
+    if (!files || files.length === 0) return;
+
+    setFolderLoading(true);
+    setError(null);
+
+    // For browser folder upload, we can't get the actual folder path.
+    // Instead, upload all files from the file picker using webkitdirectory.
+    const formData = new FormData();
+    Array.from(files).forEach((f) => formData.append('files', f));
+    formData.append('apiUrl', settings.apiUrl);
+    formData.append('apiKey', settings.apiKey);
+    formData.append('embeddingModel', settings.embeddingModel);
+
+    try {
+      // Use a batch upload approach — upload files one by one
+      const uploaded: FileResult[] = [];
+      const errors: string[] = [];
+
+      for (const file of Array.from(files)) {
+        const singleForm = new FormData();
+        singleForm.append('file', file);
+        singleForm.append('apiUrl', settings.apiUrl);
+        singleForm.append('apiKey', settings.apiKey);
+        singleForm.append('embeddingModel', settings.embeddingModel);
+
+        try {
+          const res = await fetch(`/api/knowledge/${baseId}/files`, {
+            method: 'POST',
+            body: singleForm,
+          });
+          if (!res.ok) throw new Error('Failed');
+          const data = await res.json();
+          uploaded.push(data.file);
+        } catch {
+          errors.push(file.name);
+        }
+      }
+
+      if (uploaded.length > 0) {
+        await loadBases();
+      }
+
+      if (errors.length > 0) {
+        setError(`${errors.length} files failed to upload out of ${files.length}`);
+      }
+    } catch (err) {
+      setError('Folder upload failed');
+    } finally {
+      setFolderLoading(false);
+      e.target.value = '';
+    }
+  };
+
   const handleDeleteFile = async (baseId: string, fileId: string) => {
     try {
       await fetch(`/api/knowledge/${baseId}/files/${fileId}`, { method: 'DELETE' });
@@ -105,7 +177,7 @@ export default function KnowledgePanel() {
       );
       setKnowledgeBases(updated);
     } catch (err) {
-      alert('Failed to delete file');
+      setError('Failed to delete file');
     }
   };
 
@@ -131,6 +203,17 @@ export default function KnowledgePanel() {
 
         {/* Content */}
         <div className="flex-1 overflow-y-auto p-5 space-y-4">
+          {/* Error */}
+          {error && (
+            <div className="flex items-center gap-2 px-4 py-3 rounded-lg bg-red-500/10 border border-red-500/20 text-red-400 text-sm">
+              <AlertCircle size={16} />
+              {error}
+              <button onClick={() => setError(null)} className="ml-auto text-red-400 hover:text-red-300">
+                <X size={14} />
+              </button>
+            </div>
+          )}
+
           {/* Create new */}
           {!isCreating ? (
             <button
@@ -203,7 +286,7 @@ export default function KnowledgePanel() {
                           {base.name}
                         </p>
                         <p className="text-xs text-[var(--color-text-muted)]">
-                          {base.documentCount || 0} chunks · {base.files.length} files
+                          {base.documentCount || 0} chunks · {base.files?.length || 0} files
                         </p>
                       </div>
                     </button>
@@ -222,7 +305,7 @@ export default function KnowledgePanel() {
                       )}
 
                       {/* Files */}
-                      {base.files.length > 0 && (
+                      {base.files && base.files.length > 0 && (
                         <div className="space-y-1.5">
                           {base.files.map((file) => (
                             <div
@@ -235,7 +318,7 @@ export default function KnowledgePanel() {
                                   {file.originalName}
                                 </span>
                                 <span className="text-[var(--color-text-muted)] shrink-0">
-                                  ({file.chunkCount} chunks)
+                                  ({file.chunkCount || 0} chunks)
                                 </span>
                               </div>
                               <button
@@ -249,25 +332,47 @@ export default function KnowledgePanel() {
                         </div>
                       )}
 
-                      {/* Upload */}
-                      <div className="relative">
-                        <label className={`flex items-center justify-center gap-2 w-full px-3 py-2 rounded-lg border border-dashed border-[var(--color-border)] text-xs text-[var(--color-text-muted)] hover:border-[var(--color-accent)] hover:text-[var(--color-accent)] transition-colors cursor-pointer ${uploadingBase === base.id ? 'opacity-50' : ''}`}>
+                      {/* Upload buttons */}
+                      <div className="flex gap-2">
+                        <label className={`flex-1 flex items-center justify-center gap-2 px-3 py-2 rounded-lg border border-dashed border-[var(--color-border)] text-xs text-[var(--color-text-muted)] hover:border-[var(--color-accent)] hover:text-[var(--color-accent)] transition-colors cursor-pointer ${uploadingBase === base.id ? 'opacity-50' : ''}`}>
                           {uploadingBase === base.id ? (
                             <span className="animate-pulse">Processing...</span>
                           ) : (
                             <>
                               <Upload size={14} />
-                              <span>Upload document</span>
+                              <span>Upload file</span>
                             </>
                           )}
+                          <input
+                            type="file"
+                            ref={fileInputRef}
+                            accept=".txt,.md,.pdf,.docx,.json,.csv,.js,.ts,.html,.css"
+                            onChange={(e) => handleUploadFile(base.id, e)}
+                            disabled={uploadingBase === base.id || folderLoading}
+                            className="hidden"
+                          />
+                        </label>
+                        <label className={`flex-1 flex items-center justify-center gap-2 px-3 py-2 rounded-lg border border-dashed border-[var(--color-border)] text-xs text-[var(--color-text-muted)] hover:border-green-500 hover:text-green-500 transition-colors cursor-pointer ${folderLoading ? 'opacity-50' : ''}`}>
+                          {folderLoading ? (
+                            <span className="animate-pulse">Scanning folder...</span>
+                          ) : (
+                            <>
+                              <FolderOpen size={14} />
+                              <span>Upload folder</span>
+                            </>
+                          )}
+                          <input
+                            type="file"
+                            ref={folderInputRef}
+                            // @ts-ignore — webkitdirectory is non-standard but widely supported
+                            webkitdirectory=""
+                            directory=""
+                            multiple
+                            onChange={(e) => handleUploadFolder(base.id, e)}
+                            disabled={uploadingBase === base.id || folderLoading}
+                            className="hidden"
+                          />
                         </label>
-                        <input
-                          type="file"
-                          accept=".txt,.md,.pdf,.docx"
-                          onChange={(e) => handleUploadFile(base.id, e)}
-                          disabled={uploadingBase === base.id}
-                          className="hidden"
-                        />
                       </div>
                     </div>
                   )}

frontend/src/services/api.ts

@@ -8,7 +8,8 @@ export async function* streamChatCompletion(
   temperature: number,
   maxTokens: number,
   systemPrompt: string,
-  abortSignal: AbortSignal
+  abortSignal: AbortSignal,
+  conversationId?: string
 ): AsyncGenerator<OpenAIStreamChunk, void, unknown> {
   const formattedMessages: OpenAIMessage[] = [
     { role: 'system', content: systemPrompt },
@@ -28,6 +29,7 @@ export async function* streamChatCompletion(
       max_tokens: maxTokens,
       messages: formattedMessages,
       stream: true,
+      conversationId,
     }),
     signal: abortSignal,
   });