fix: prompt caching, conversation length management and token usage display

src/renderer/components/AssistantSidebar/AssistantSidebar.tsx

@@ -123,11 +123,24 @@ export const AssistantSidebar: React.FC = () => {
       }
     });
 
+    const unsubTokenUsage = window.electronAPI?.chat.onTokenUsage((data) => {
+      if (data.conversationId === conversationId) {
+        useAppStore.getState().setChatTokenUsage(conversationId, {
+          inputTokens: data.cumulativeInputTokens,
+          outputTokens: data.cumulativeOutputTokens,
+          cacheReadTokens: data.cumulativeCacheReadTokens,
+          cacheWriteTokens: data.cumulativeCacheWriteTokens,
+          totalTokens: data.cumulativeTotalTokens,
+        });
+      }
+    });
+
     return () => {
       unsubDelta?.();
       unsubToolCall?.();
       unsubToolResult?.();
       unsubTitle?.();
+      unsubTokenUsage?.();
     };
   }, [conversationId, appendStreamDelta, recordToolCall, recordToolResult]);
 

src/renderer/components/ChatPanel/ChatPanel.tsx

@@ -148,11 +148,24 @@ export const ChatPanel: React.FC<ChatPanelProps> = ({ conversationId }) => {
       }
     });
 
+    const unsubTokenUsage = window.electronAPI?.chat.onTokenUsage((data) => {
+      if (data.conversationId === conversationId) {
+        useAppStore.getState().setChatTokenUsage(conversationId, {
+          inputTokens: data.cumulativeInputTokens,
+          outputTokens: data.cumulativeOutputTokens,
+          cacheReadTokens: data.cumulativeCacheReadTokens,
+          cacheWriteTokens: data.cumulativeCacheWriteTokens,
+          totalTokens: data.cumulativeTotalTokens,
+        });
+      }
+    });
+
     return () => {
       unsubDelta?.();
       unsubToolCall?.();
       unsubToolResult?.();
       unsubTitle?.();
+      unsubTokenUsage?.();
     };
   }, [conversationId, loadData, scrollToBottom, checkReady, appendStreamDelta, recordToolCall, recordToolResult]);
 

src/renderer/components/StatusBar/StatusBar.css

@@ -95,6 +95,11 @@
   border-radius: 3px;
 }
 
+.status-bar-item.token-usage {
+  font-variant-numeric: tabular-nums;
+  opacity: 0.85;
+}
+
 .status-bar-item.language-badge {
   border: 1px solid var(--vscode-statusBar-border, transparent);
   border-radius: 3px;

src/renderer/components/StatusBar/StatusBar.tsx

@@ -21,6 +21,9 @@ export const StatusBar: React.FC = () => {
     selectedPostId,
     totalPosts,
     picoTheme,
+    tabs,
+    activeTabId,
+    chatTokenUsage,
   } = useAppStore();
 
   const [selectedPostStatus, setSelectedPostStatus] = useState<string | null>(null);
@@ -39,6 +42,10 @@ export const StatusBar: React.FC = () => {
   const runningTasks = tasks.filter(t => t.status === 'running');
   const activeTheme = getRendererPicoTheme(picoTheme);
 
+  // Detect active chat tab and its token usage
+  const activeTab = tabs.find(tab => tab.id === activeTabId);
+  const activeChatUsage = activeTab?.type === 'chat' ? chatTokenUsage[activeTab.id] : null;
+
   return (
     <div className="status-bar">
       <div className="status-bar-left">
@@ -74,6 +81,17 @@ export const StatusBar: React.FC = () => {
           <span>{t('statusBar.media', { count: media.length })}</span>
         </div>
 
+        {/* Token Usage (visible when chat tab is active) */}
+        {activeChatUsage && (
+          <div className="status-bar-item token-usage">
+            <span>{t('statusBar.tokens', {
+              input: activeChatUsage.inputTokens.toLocaleString(),
+              output: activeChatUsage.outputTokens.toLocaleString(),
+              cached: activeChatUsage.cacheReadTokens.toLocaleString(),
+            })}</span>
+          </div>
+        )}
+
         <div className="status-bar-item theme-badge">
           <span>{t('statusBar.theme', { theme: activeTheme })}</span>
         </div>

src/renderer/i18n/locales/de.json

@@ -817,6 +817,7 @@
   "statusBar.posts": "{count} Beiträge",
   "statusBar.media": "{count} Medien",
   "statusBar.more": "+{count} weitere",
+  "statusBar.tokens": "Token: {input} ein / {output} aus ({cached} zwischengesp.)",
   "statusBar.theme": "Theme: {theme}",
   "statusBar.ui": "UI",
   "statusBar.uiLanguage": "UI-Sprache",

src/renderer/i18n/locales/en.json

@@ -817,6 +817,7 @@
   "statusBar.posts": "{count} posts",
   "statusBar.media": "{count} media",
   "statusBar.more": "+{count} more",
+  "statusBar.tokens": "Tokens: {input} in / {output} out ({cached} cached)",
   "statusBar.theme": "Theme: {theme}",
   "statusBar.ui": "UI",
   "statusBar.uiLanguage": "UI language",

src/renderer/i18n/locales/es.json

@@ -817,6 +817,7 @@
   "statusBar.posts": "Publicaciones",
   "statusBar.media": "Medios",
   "statusBar.more": "+{count} más",
+  "statusBar.tokens": "Tokens: {input} entr. / {output} sal. ({cached} en caché)",
   "statusBar.theme": "Tema: {theme}",
   "statusBar.ui": "UI",
   "statusBar.uiLanguage": "Idioma de la interfaz",

src/renderer/i18n/locales/fr.json

@@ -815,6 +815,7 @@
   "statusBar.posts": "Articles",
   "statusBar.media": "Médias",
   "statusBar.more": "+{count} en plus",
+  "statusBar.tokens": "Tokens : {input} entr. / {output} sort. ({cached} en cache)",
   "statusBar.theme": "Thème : {theme}",
   "statusBar.ui": "UI",
   "statusBar.uiLanguage": "Langue de l’interface",

src/renderer/i18n/locales/it.json

@@ -815,6 +815,7 @@
   "statusBar.posts": "Articoli",
   "statusBar.media": "Media",
   "statusBar.more": "+{count} in più",
+  "statusBar.tokens": "Token: {input} ingr. / {output} usc. ({cached} in cache)",
   "statusBar.theme": "Tema: {theme}",
   "statusBar.ui": "UI",
   "statusBar.uiLanguage": "Lingua interfaccia",

src/renderer/store/appStore.ts

@@ -100,6 +100,15 @@ interface AppState {
   isLoading: boolean;
   error: string | null;
 
+  // Chat token usage (keyed by conversationId, ephemeral - not persisted)
+  chatTokenUsage: Record<string, {
+    inputTokens: number;
+    outputTokens: number;
+    cacheReadTokens: number;
+    cacheWriteTokens: number;
+    totalTokens: number;
+  }>;
+
   // Project Actions
   setProjects: (projects: ProjectData[]) => void;
   setActiveProject: (project: ProjectData | null) => void;
@@ -160,6 +169,16 @@ interface AppState {
   // Loading Actions
   setLoading: (loading: boolean) => void;
   setError: (error: string | null) => void;
+
+  // Chat token usage actions
+  setChatTokenUsage: (conversationId: string, usage: {
+    inputTokens: number;
+    outputTokens: number;
+    cacheReadTokens: number;
+    cacheWriteTokens: number;
+    totalTokens: number;
+  }) => void;
+  clearChatTokenUsage: (conversationId: string) => void;
 }
 
 export const useAppStore = create<AppState>()(
@@ -212,6 +231,9 @@ export const useAppStore = create<AppState>()(
       isLoading: false,
       error: null,
 
+      // Chat token usage (ephemeral, not persisted)
+      chatTokenUsage: {},
+
       // Project Actions
       setProjects: (projects) => set({ projects }),
       setActiveProject: (activeProject) => set({ activeProject }),
@@ -388,6 +410,15 @@ export const useAppStore = create<AppState>()(
       // Loading Actions
       setLoading: (isLoading) => set({ isLoading }),
       setError: (error) => set({ error }),
+
+      // Chat token usage actions
+      setChatTokenUsage: (conversationId, usage) => set((state) => ({
+        chatTokenUsage: { ...state.chatTokenUsage, [conversationId]: usage },
+      })),
+      clearChatTokenUsage: (conversationId) => set((state) => {
+        const { [conversationId]: _, ...rest } = state.chatTokenUsage;
+        return { chatTokenUsage: rest };
+      }),
     }),
     {
       name: STORAGE_KEY,