merge: sync with upstream/main — session reports, cost calculation, Linux title bar, auto-expand AI groups

Brings in upstream changes:
- Session analysis reports (overview, cost, tokens, tools, git, quality)
- Unified cost calculation with LiteLLM pricing data
- Custom title bar for Linux with native toggle
- Auto-expand AI response groups setting
- MoreMenu toolbar component
- Various fixes (window drag, Ctrl+R, notification guard)

All merge conflicts resolved preserving both fork features (team management,
agent language, fullscreen, diff view) and upstream additions.

CHANGELOG.md

@@ -7,6 +7,9 @@ The format is based on Keep a Changelog and this project follows Semantic Versio
 ## [Unreleased]
 
 ### Added
+- `general.autoExpandAIGroups` setting: automatically expands all AI response groups when opening a transcript or when new AI responses arrive in a live session. Defaults to off. Stored in the on-disk config so it persists across restarts.
+
+
 - Strict IPC input validation guards for project/session/subagent/search limits.
 - `get-waterfall-data` IPC endpoint implementation.
 - Cross-platform path normalization in renderer path resolvers.

CONTRIBUTING.md

@@ -23,10 +23,27 @@ pnpm build
 ```
 
 ## Pull Request Guidelines
-- Keep changes focused and small.
+- Keep changes focused and small — one purpose per PR.
 - Add/adjust tests for behavior changes.
 - Update docs when changing public behavior or setup.
 - Use clear PR titles and include a short validation checklist.
+- **Large changes (new features, new dependencies, large data additions) must have a discussion in an Issue first.** Do not open a large PR without prior agreement on the approach.
+- Avoid committing large hardcoded data blobs. If data can be fetched at runtime or generated at build time, prefer that approach.
+
+## AI-Assisted Contributions
+
+AI coding tools are welcome, but **you are responsible for what you submit**:
+
+- **Review before submitting.** Read every line of AI-generated code and understand what it does. Do not submit raw, unreviewed AI output.
+- **Do not commit AI workflow artifacts.** Planning documents, session logs, step-by-step plans, or other outputs from AI tools (e.g. `docs/plans/`, `.speckit/`, etc.) do not belong in the repository.
+- **Test it yourself.** AI-generated code must be manually verified — run the app, confirm the feature works, check edge cases.
+- **Keep it intentional.** Every line in your PR should exist for a reason you can explain. If you can't explain why a piece of code is there, remove it.
+
+## What Does NOT Belong in the Repo
+- Personal planning/workflow artifacts (AI session plans, task lists, etc.)
+- Large static data that could be fetched at runtime
+- Generated files that aren't part of the build output
+- Experimental features without prior discussion
 
 ## Commit Style
 - Prefer conventional commits (`feat:`, `fix:`, `chore:`, `docs:`).

package.json

@@ -20,6 +20,7 @@
   "scripts": {
     "dev": "electron-vite dev",
     "dev:kill": "node bin/kill-dev.js",
+    "prebuild": "tsx scripts/fetch-pricing-data.ts",
     "build": "electron-vite build",
     "dist": "electron-builder --mac --win --linux",
     "dist:mac": "electron-builder --mac --publish always",
@@ -156,6 +157,12 @@
     "asarUnpack": [
       "out/renderer/**"
     ],
+    "extraResources": [
+      {
+        "from": "resources/pricing.json",
+        "to": "pricing.json"
+      }
+    ],
     "npmRebuild": false,
     "extraMetadata": {
       "main": "dist-electron/main/index.cjs"

scripts/fetch-pricing-data.ts

@@ -0,0 +1,113 @@
+#!/usr/bin/env tsx
+
+/**
+ * Fetch latest model pricing from LiteLLM and save to renderer assets.
+ * Filters to Claude models only to reduce bundle size.
+ * Runs automatically during prebuild.
+ */
+
+import * as fs from 'fs';
+import * as path from 'path';
+import { fileURLToPath } from 'url';
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+
+const LITELLM_PRICING_URL =
+  'https://raw.githubusercontent.com/BerriAI/litellm/main/model_prices_and_context_window.json';
+const OUTPUT_PATH = path.join(__dirname, '..', 'resources', 'pricing.json');
+const FETCH_TIMEOUT = 10000; // 10 seconds
+
+interface ModelPricing {
+  input_cost_per_token: number;
+  output_cost_per_token: number;
+  cache_creation_input_token_cost?: number;
+  cache_read_input_token_cost?: number;
+  input_cost_per_token_above_200k_tokens?: number;
+  output_cost_per_token_above_200k_tokens?: number;
+  cache_creation_input_token_cost_above_200k_tokens?: number;
+  cache_read_input_token_cost_above_200k_tokens?: number;
+  [key: string]: unknown;
+}
+
+function isValidModelPricing(entry: unknown): entry is ModelPricing {
+  return (
+    typeof entry === 'object' &&
+    entry !== null &&
+    'input_cost_per_token' in entry &&
+    'output_cost_per_token' in entry &&
+    typeof (entry as ModelPricing).input_cost_per_token === 'number' &&
+    typeof (entry as ModelPricing).output_cost_per_token === 'number'
+  );
+}
+
+function isClaudeModel(modelName: string): boolean {
+  const lower = modelName.toLowerCase();
+  return lower.includes('claude');
+}
+
+async function fetchPricingData(): Promise<Record<string, ModelPricing>> {
+  console.log('Fetching pricing data from LiteLLM...');
+
+  const controller = new AbortController();
+  const timeout = setTimeout(() => controller.abort(), FETCH_TIMEOUT);
+
+  try {
+    const response = await fetch(LITELLM_PRICING_URL, { signal: controller.signal });
+    clearTimeout(timeout);
+
+    if (!response.ok) {
+      throw new Error(`HTTP ${response.status}: ${response.statusText}`);
+    }
+
+    const data = (await response.json()) as Record<string, unknown>;
+    console.log(`Fetched pricing for ${Object.keys(data).length} models`);
+
+    // Filter to Claude models only and validate entries
+    const claudeModels: Record<string, ModelPricing> = {};
+    for (const [modelName, entry] of Object.entries(data)) {
+      if (isClaudeModel(modelName) && isValidModelPricing(entry)) {
+        claudeModels[modelName] = entry;
+      }
+    }
+
+    console.log(`Filtered to ${Object.keys(claudeModels).length} Claude models`);
+    return claudeModels;
+  } catch (error) {
+    clearTimeout(timeout);
+    if (error instanceof Error && error.name === 'AbortError') {
+      throw new Error('Fetch timeout after 10 seconds');
+    }
+    throw error;
+  }
+}
+
+async function main(): Promise<void> {
+  try {
+    console.log('Fetching pricing data for models...');
+    const pricing = await fetchPricingData();
+
+    // Ensure output directory exists
+    const outputDir = path.dirname(OUTPUT_PATH);
+    if (!fs.existsSync(outputDir)) {
+      fs.mkdirSync(outputDir, { recursive: true });
+    }
+
+    // Write formatted JSON
+    fs.writeFileSync(OUTPUT_PATH, JSON.stringify(pricing, null, 2), 'utf-8');
+
+    // Calculate file size
+    const stats = fs.statSync(OUTPUT_PATH);
+    const sizeKB = (stats.size / 1024).toFixed(2);
+
+    console.log(`✓ Wrote pricing data to ${OUTPUT_PATH}`);
+    console.log(`  Bundle size: ${sizeKB} KB`);
+  } catch (error) {
+    console.error('Failed to fetch pricing data:', error);
+    console.error('Build will continue with existing pricing.json if available');
+    // Don't fail the build - allow using existing pricing.json
+    process.exit(0);
+  }
+}
+
+main();

src/main/index.ts

@@ -454,8 +454,8 @@ function syncTrafficLightPosition(win: BrowserWindow): void {
  */
 function createWindow(): void {
   const isMac = process.platform === 'darwin';
-  const isLinux = process.platform === 'linux';
   const iconPath = isMac ? undefined : getWindowIconPath();
+  const useNativeTitleBar = !isMac && configManager.getConfig().general.useNativeTitleBar;
   mainWindow = new BrowserWindow({
     width: DEFAULT_WINDOW_WIDTH,
     height: DEFAULT_WINDOW_HEIGHT,
@@ -466,7 +466,7 @@ function createWindow(): void {
       contextIsolation: true,
     },
     backgroundColor: '#1a1a1a',
-    ...(isLinux ? {} : { titleBarStyle: 'hidden' as const }),
+    ...(useNativeTitleBar ? {} : { titleBarStyle: 'hidden' as const }),
     ...(isMac && { trafficLightPosition: getTrafficLightPositionForZoom(1) }),
     title: 'Claude Agent Teams UI',
   });
@@ -527,7 +527,17 @@ function createWindow(): void {
   const ZOOM_OUT_KEYS = new Set(['-', '_']);
   mainWindow.webContents.on('before-input-event', (event, input) => {
     if (!mainWindow || mainWindow.isDestroyed()) return;
-    if (!input.meta || input.type !== 'keyDown') return;
+    if (input.type !== 'keyDown') return;
+
+    // Prevent Electron's default Ctrl+R / Cmd+R page reload so the renderer
+    // keyboard handler can use it as "Refresh Session" (fixes #58).
+    // Also prevent Ctrl+Shift+R / Cmd+Shift+R (hard reload).
+    if ((input.control || input.meta) && input.key.toLowerCase() === 'r') {
+      event.preventDefault();
+      return;
+    }
+
+    if (!input.meta) return;
 
     const currentLevel = mainWindow.webContents.getZoomLevel();
 

src/main/ipc/configValidation.ts

@@ -204,6 +204,8 @@ function validateGeneralSection(data: unknown): ValidationSuccess<'general'> | V
     'defaultTab',
     'claudeRootPath',
     'agentLanguage',
+    'autoExpandAIGroups',
+    'useNativeTitleBar',
   ];
 
   const result: Partial<GeneralConfig> = {};
@@ -274,6 +276,18 @@ function validateGeneralSection(data: unknown): ValidationSuccess<'general'> | V
         }
         result.agentLanguage = value.trim();
         break;
+      case 'autoExpandAIGroups':
+        if (typeof value !== 'boolean') {
+          return { valid: false, error: `general.${key} must be a boolean` };
+        }
+        result.autoExpandAIGroups = value;
+        break;
+      case 'useNativeTitleBar':
+        if (typeof value !== 'boolean') {
+          return { valid: false, error: `general.${key} must be a boolean` };
+        }
+        result.useNativeTitleBar = value;
+        break;
       default:
         return { valid: false, error: `Unsupported general key: ${key}` };
     }

src/main/ipc/window.ts

@@ -5,9 +5,9 @@
  */
 
 import { createLogger } from '@shared/utils/logger';
+import { app, BrowserWindow, type IpcMain } from 'electron';
 
 const WINDOW_IS_FULLSCREEN = 'window:isFullScreen';
-import { BrowserWindow, type IpcMain } from 'electron';
 
 const logger = createLogger('IPC:window');
 
@@ -47,6 +47,11 @@ export function registerWindowHandlers(ipcMain: IpcMain): void {
     return win != null && !win.isDestroyed() && win.isFullScreen();
   });
 
+  ipcMain.handle('app:relaunch', () => {
+    app.relaunch();
+    app.exit(0);
+  });
+
   logger.info('Window handlers registered');
 }
 
@@ -56,5 +61,6 @@ export function removeWindowHandlers(ipcMain: IpcMain): void {
   ipcMain.removeHandler('window:close');
   ipcMain.removeHandler('window:isMaximized');
   ipcMain.removeHandler(WINDOW_IS_FULLSCREEN);
+  ipcMain.removeHandler('app:relaunch');
   logger.info('Window handlers removed');
 }

src/main/services/infrastructure/ConfigManager.ts

@@ -182,6 +182,8 @@ export interface GeneralConfig {
   defaultTab: 'dashboard' | 'last-session';
   claudeRootPath: string | null;
   agentLanguage: string;
+  autoExpandAIGroups: boolean;
+  useNativeTitleBar: boolean;
 }
 
 export interface DisplayConfig {
@@ -250,6 +252,8 @@ const DEFAULT_CONFIG: AppConfig = {
     defaultTab: 'dashboard',
     claudeRootPath: null,
     agentLanguage: 'system',
+    autoExpandAIGroups: false,
+    useNativeTitleBar: false,
   },
   display: {
     showTimestamps: true,

src/main/services/infrastructure/NotificationManager.ts

@@ -373,8 +373,12 @@ export class NotificationManager extends EventEmitter {
    * Shows a native macOS notification for an error.
    */
   private showNativeNotification(error: DetectedError): void {
-    // Check if Notification is supported
-    if (!Notification.isSupported()) {
+    // Guard against standalone/Docker mode where Electron's Notification API is unavailable
+    if (
+      typeof Notification === 'undefined' ||
+      typeof Notification.isSupported !== 'function' ||
+      !Notification.isSupported()
+    ) {
       logger.warn('Native notifications not supported');
       return;
     }

src/main/types/chunks.ts

@@ -461,6 +461,7 @@ export const EMPTY_METRICS: SessionMetrics = {
   cacheReadTokens: 0,
   cacheCreationTokens: 0,
   messageCount: 0,
+  costUsd: 0,
 };
 
 // =============================================================================

src/main/utils/jsonl.ts

@@ -9,6 +9,7 @@
 
 import { isCommandOutputContent, sanitizeDisplayContent } from '@shared/utils/contentSanitizer';
 import { createLogger } from '@shared/utils/logger';
+import { calculateMessageCost } from '@shared/utils/pricing';
 import * as readline from 'readline';
 
 import { LocalFileSystemProvider } from '../services/infrastructure/LocalFileSystemProvider';
@@ -228,7 +229,6 @@ export function calculateMetrics(messages: ParsedMessage[]): SessionMetrics {
   let outputTokens = 0;
   let cacheReadTokens = 0;
   let cacheCreationTokens = 0;
-  const costUsd = 0;
 
   // Get timestamps for duration (loop instead of Math.min/max spread to avoid stack overflow on large sessions)
   const timestamps = messages.map((m) => m.timestamp.getTime()).filter((t) => !isNaN(t));
@@ -244,12 +244,30 @@ export function calculateMetrics(messages: ParsedMessage[]): SessionMetrics {
     }
   }
 
+  // Calculate cost per-message, then sum (tiered pricing applies per-API-call, not to aggregated totals)
+  let costUsd = 0;
+
   for (const msg of messages) {
     if (msg.usage) {
-      inputTokens += msg.usage.input_tokens ?? 0;
-      outputTokens += msg.usage.output_tokens ?? 0;
-      cacheReadTokens += msg.usage.cache_read_input_tokens ?? 0;
-      cacheCreationTokens += msg.usage.cache_creation_input_tokens ?? 0;
+      const msgInputTokens = msg.usage.input_tokens ?? 0;
+      const msgOutputTokens = msg.usage.output_tokens ?? 0;
+      const msgCacheReadTokens = msg.usage.cache_read_input_tokens ?? 0;
+      const msgCacheCreationTokens = msg.usage.cache_creation_input_tokens ?? 0;
+
+      inputTokens += msgInputTokens;
+      outputTokens += msgOutputTokens;
+      cacheReadTokens += msgCacheReadTokens;
+      cacheCreationTokens += msgCacheCreationTokens;
+
+      if (msg.model) {
+        costUsd += calculateMessageCost(
+          msg.model,
+          msgInputTokens,
+          msgOutputTokens,
+          msgCacheReadTokens,
+          msgCacheCreationTokens
+        );
+      }
     }
   }
 
@@ -261,7 +279,7 @@ export function calculateMetrics(messages: ParsedMessage[]): SessionMetrics {
     cacheReadTokens,
     cacheCreationTokens,
     messageCount: messages.length,
-    costUsd: costUsd > 0 ? costUsd : undefined,
+    costUsd,
   };
 }
 

src/preload/constants/ipcChannels.ts

@@ -178,6 +178,9 @@ export const WINDOW_IS_FULLSCREEN = 'window:isFullScreen';
 /** Event: (isFullScreen: boolean) when window enters or leaves fullscreen */
 export const WINDOW_FULLSCREEN_CHANGED = 'window:fullscreen-changed';
 
+/** Relaunch the application */
+export const APP_RELAUNCH = 'app:relaunch';
+
 // =============================================================================
 // Team API Channels
 // =============================================================================

src/preload/index.ts

@@ -2,6 +2,7 @@ import { WINDOW_ZOOM_FACTOR_CHANGED_CHANNEL } from '@shared/constants';
 import { contextBridge, ipcRenderer } from 'electron';
 
 import {
+  APP_RELAUNCH,
   CONTEXT_CHANGED,
   CONTEXT_GET_ACTIVE,
   CONTEXT_LIST,
@@ -409,6 +410,7 @@ const electronAPI: ElectronAPI = {
     close: () => ipcRenderer.invoke(WINDOW_CLOSE),
     isMaximized: () => ipcRenderer.invoke(WINDOW_IS_MAXIMIZED) as Promise<boolean>,
     isFullScreen: () => ipcRenderer.invoke(WINDOW_IS_FULLSCREEN) as Promise<boolean>,
+    relaunch: () => ipcRenderer.invoke(APP_RELAUNCH),
   },
 
   onFullScreenChange: (callback: (isFullScreen: boolean) => void): (() => void) => {

src/renderer/api/httpClient.ts

@@ -532,6 +532,7 @@ export class HttpAPIClient implements ElectronAPI {
     close: async (): Promise<void> => {},
     isMaximized: async (): Promise<boolean> => false,
     isFullScreen: async (): Promise<boolean> => false,
+    relaunch: async (): Promise<void> => {},
   };
 
   onFullScreenChange =

src/renderer/components/chat/AIChatGroup.tsx

@@ -245,6 +245,9 @@ const AIChatGroupInner = ({
     return null;
   }, [aiGroup.responses]);
 
+  // Get the total cost
+  const costUSD = aiGroup.metrics.costUsd;
+
   // Calculate thinking and text output tokens from assistant message content blocks
   // These are estimated from the actual content, providing breakdown of output token usage
   const { thinkingTokens, textOutputTokens } = useMemo(() => {
@@ -470,6 +473,7 @@ const AIChatGroupInner = ({
                 contextStats={contextStats}
                 phaseNumber={phaseNumber}
                 totalPhases={totalPhases}
+                costUsd={costUSD}
               />
             )}
 

src/renderer/components/chat/ChatHistory.tsx

@@ -1,15 +1,21 @@
 import { useCallback, useEffect, useMemo, useRef, useState } from 'react';
 
-import { useAutoScrollBottom } from '@renderer/hooks/useAutoScrollBottom';
+import { isNearBottom, useAutoScrollBottom } from '@renderer/hooks/useAutoScrollBottom';
 import { useTabNavigationController } from '@renderer/hooks/useTabNavigationController';
 import { useTabUI } from '@renderer/hooks/useTabUI';
 import { useVisibleAIGroup } from '@renderer/hooks/useVisibleAIGroup';
 import { useStore } from '@renderer/store';
 import { useVirtualizer } from '@tanstack/react-virtual';
-import { ChevronRight, Users } from 'lucide-react';
+import { ChevronRight, ChevronsDown, Users } from 'lucide-react';
 import { useShallow } from 'zustand/react/shallow';
 
 import { SessionContextPanel } from './SessionContextPanel/index';
+
+/** Pixels from bottom considered "near bottom" for scroll-button visibility and auto-scroll. */
+const SCROLL_THRESHOLD = 300;
+/** Must match the `w-80` (320px) context panel width used in the layout below. */
+const CONTEXT_PANEL_WIDTH_PX = 320;
+
 import { ChatHistoryEmptyState } from './ChatHistoryEmptyState';
 import { ChatHistoryItem } from './ChatHistoryItem';
 import { ChatHistoryLoadingState } from './ChatHistoryLoadingState';
@@ -60,6 +66,7 @@ export const ChatHistory = ({ tabId }: ChatHistoryProps): JSX.Element => {
     setTabVisibleAIGroup,
     teams,
     openTeamTab,
+    openSessionReport,
   } = useStore(
     useShallow((s) => ({
       searchQuery: s.searchQuery,
@@ -74,6 +81,7 @@ export const ChatHistory = ({ tabId }: ChatHistoryProps): JSX.Element => {
       setTabVisibleAIGroup: s.setTabVisibleAIGroup,
       teams: s.teams,
       openTeamTab: s.openTeamTab,
+      openSessionReport: s.openSessionReport,
     }))
   );
 
@@ -98,6 +106,14 @@ export const ChatHistory = ({ tabId }: ChatHistoryProps): JSX.Element => {
     sessionDetail,
   } = tabData;
 
+  // Compute combined subagent cost from process metrics
+  const subagentCostUsd = useMemo(() => {
+    const processes = sessionDetail?.processes;
+    if (!processes || processes.length === 0) return undefined;
+    const total = processes.reduce((sum, p) => sum + (p.metrics.costUsd ?? 0), 0);
+    return total > 0 ? total : undefined;
+  }, [sessionDetail?.processes]);
+
   // State for Context button hover (local state OK - doesn't need per-tab isolation)
   const [isContextButtonHovered, setIsContextButtonHovered] = useState(false);
 
@@ -355,11 +371,21 @@ export const ChatHistory = ({ tabId }: ChatHistoryProps): JSX.Element => {
     rootRef: scrollContainerRef,
   });
 
+  // Scroll-to-bottom button visibility
+  const [showScrollButton, setShowScrollButton] = useState(false);
+
+  const checkScrollButton = useCallback(() => {
+    const container = scrollContainerRef.current;
+    if (!container) return;
+    const { scrollTop, scrollHeight, clientHeight } = container;
+    setShowScrollButton(!isNearBottom(scrollTop, scrollHeight, clientHeight, SCROLL_THRESHOLD));
+  }, []);
+
   // Auto-follow when conversation updates, but only if the user was already near bottom.
   // This preserves manual reading position when the user scrolls up.
   // Disabled during navigation to prevent conflicts with deep-link/search scrolling.
-  useAutoScrollBottom([conversation], {
-    threshold: 150,
+  const { scrollToBottom } = useAutoScrollBottom([conversation], {
+    threshold: SCROLL_THRESHOLD,
     smoothDuration: 300,
     autoBehavior: 'auto',
     disabled: shouldDisableAutoScroll,
@@ -367,6 +393,11 @@ export const ChatHistory = ({ tabId }: ChatHistoryProps): JSX.Element => {
     resetKey: effectiveTabId,
   });
 
+  // Re-check button visibility whenever conversation updates
+  useEffect(() => {
+    checkScrollButton();
+  }, [conversation, checkScrollButton]);
+
   // Callback to register AI group refs (combines with visibility hook)
   const registerAIGroupRefCombined = useCallback(
     (groupId: string) => {
@@ -730,12 +761,13 @@ export const ChatHistory = ({ tabId }: ChatHistoryProps): JSX.Element => {
       className="flex flex-1 flex-col overflow-hidden"
       style={{ backgroundColor: 'var(--color-surface)' }}
     >
-      <div className="flex flex-1 overflow-hidden">
+      <div className="relative flex flex-1 overflow-hidden">
         {/* Chat content */}
         <div
           ref={scrollContainerRef}
           className="flex-1 overflow-y-auto"
           style={{ backgroundColor: 'var(--color-surface)' }}
+          onScroll={checkScrollButton}
         >
           {/* Sticky Context button */}
           {allContextInjections.length > 0 && (
@@ -845,6 +877,30 @@ export const ChatHistory = ({ tabId }: ChatHistoryProps): JSX.Element => {
           </div>
         </div>
 
+        {/* Scroll to bottom button */}
+        {showScrollButton && (
+          <button
+            onClick={() => {
+              scrollToBottom('smooth');
+              setShowScrollButton(false);
+            }}
+            className="absolute bottom-5 z-20 flex items-center gap-1.5 rounded-full px-3 py-1.5 text-xs shadow-lg backdrop-blur-md transition-all"
+            style={{
+              right:
+                isContextPanelVisible && allContextInjections.length > 0
+                  ? `calc(${CONTEXT_PANEL_WIDTH_PX}px + 1rem)`
+                  : '1rem',
+              backgroundColor: 'var(--context-btn-bg)',
+              color: 'var(--color-text-secondary)',
+              border: '1px solid var(--color-border-emphasis)',
+            }}
+            title="Scroll to bottom"
+          >
+            <ChevronsDown className="size-3.5" />
+            <span>Bottom</span>
+          </button>
+        )}
+
         {/* Context panel sidebar */}
         {isContextPanelVisible && allContextInjections.length > 0 && (
           <div className="w-80 shrink-0">
@@ -856,6 +912,9 @@ export const ChatHistory = ({ tabId }: ChatHistoryProps): JSX.Element => {
               onNavigateToTool={handleNavigateToTool}
               onNavigateToUserGroup={handleNavigateToUserGroup}
               totalSessionTokens={lastAiGroupTotalTokens}
+              sessionMetrics={sessionDetail?.metrics}
+              subagentCostUsd={subagentCostUsd}
+              onViewReport={effectiveTabId ? () => openSessionReport(effectiveTabId) : undefined}
               phaseInfo={sessionPhaseInfo ?? undefined}
               selectedPhase={selectedContextPhase}
               onPhaseChange={setSelectedContextPhase}

src/renderer/components/chat/SessionContextPanel/components/SessionContextHeader.tsx

@@ -12,6 +12,7 @@ import {
   COLOR_TEXT_MUTED,
   COLOR_TEXT_SECONDARY,
 } from '@renderer/constants/cssVariables';
+import { formatCostUsd } from '@shared/utils/costFormatting';
 import { ArrowDownWideNarrow, FileText, LayoutList, X } from 'lucide-react';
 
 import { formatTokens } from '../utils/formatting';
@@ -20,12 +21,16 @@ import { SessionContextHelpTooltip } from './SessionContextHelpTooltip';
 
 import type { ContextViewMode } from '../types';
 import type { ContextPhaseInfo } from '@renderer/types/contextInjection';
+import type { SessionMetrics } from '@shared/types';
 
 interface SessionContextHeaderProps {
   injectionCount: number;
   totalTokens: number;
   totalSessionTokens?: number;
+  sessionMetrics?: SessionMetrics;
+  subagentCostUsd?: number;
   onClose?: () => void;
+  onViewReport?: () => void;
   phaseInfo?: ContextPhaseInfo;
   selectedPhase: number | null;
   onPhaseChange: (phase: number | null) => void;
@@ -37,7 +42,10 @@ export const SessionContextHeader = ({
   injectionCount,
   totalTokens,
   totalSessionTokens,
+  sessionMetrics,
+  subagentCostUsd,
   onClose,
+  onViewReport,
   phaseInfo,
   selectedPhase,
   onPhaseChange,
@@ -115,6 +123,46 @@ export const SessionContextHeader = ({
         )}
       </div>
 
+      {/* Session Metrics Breakdown */}
+      {sessionMetrics && (
+        <div
+          className="mt-2 grid grid-cols-2 gap-x-4 gap-y-1 pt-2 text-[10px]"
+          style={{ borderTop: `1px solid ${COLOR_BORDER_SUBTLE}` }}
+        >
+          {/* Cost */}
+          {sessionMetrics.costUsd !== undefined && sessionMetrics.costUsd > 0 && (
+            <div className="col-span-2">
+              <span style={{ color: COLOR_TEXT_MUTED }}>Session Cost: </span>
+              <span className="font-medium tabular-nums" style={{ color: COLOR_TEXT_SECONDARY }}>
+                {formatCostUsd(sessionMetrics.costUsd + (subagentCostUsd ?? 0))}
+              </span>
+              {subagentCostUsd !== undefined && subagentCostUsd > 0 && (
+                <span style={{ color: COLOR_TEXT_MUTED }}>
+                  {' ('}
+                  {formatCostUsd(sessionMetrics.costUsd)}
+                  {' parent + '}
+                  {formatCostUsd(subagentCostUsd)}
+                  {' subagents'}
+                  {onViewReport && (
+                    <>
+                      {' · '}
+                      <button
+                        onClick={onViewReport}
+                        className="underline"
+                        style={{ color: COLOR_TEXT_SECONDARY }}
+                      >
+                        details
+                      </button>
+                    </>
+                  )}
+                  {')'}
+                </span>
+              )}
+            </div>
+          )}
+        </div>
+      )}
+
       {/* Phase selector - only shown when compactions exist */}
       {phaseInfo && phaseInfo.phases.length > 1 && (
         <div

src/renderer/components/chat/SessionContextPanel/index.tsx

@@ -48,6 +48,9 @@ export const SessionContextPanel = ({
   onNavigateToTool,
   onNavigateToUserGroup,
   totalSessionTokens,
+  sessionMetrics,
+  subagentCostUsd,
+  onViewReport,
   phaseInfo,
   selectedPhase,
   onPhaseChange,
@@ -190,7 +193,10 @@ export const SessionContextPanel = ({
         injectionCount={injections.length}
         totalTokens={totalTokens}
         totalSessionTokens={totalSessionTokens}
+        sessionMetrics={sessionMetrics}
+        subagentCostUsd={subagentCostUsd}
         onClose={onClose}
+        onViewReport={onViewReport}
         phaseInfo={phaseInfo}
         selectedPhase={selectedPhase}
         onPhaseChange={onPhaseChange}

src/renderer/components/chat/SessionContextPanel/types.ts

@@ -4,6 +4,7 @@
 
 import type { ClaudeMdSource } from '@renderer/types/claudeMd';
 import type { ContextInjection, ContextPhaseInfo } from '@renderer/types/contextInjection';
+import type { SessionMetrics } from '@shared/types';
 
 // =============================================================================
 // Props Interface
@@ -24,6 +25,12 @@ export interface SessionContextPanelProps {
   onNavigateToUserGroup?: (turnIndex: number) => void;
   /** Total session tokens (input + output + cache) for comparison */
   totalSessionTokens?: number;
+  /** Full session metrics (input, output, cache tokens, cost) */
+  sessionMetrics?: SessionMetrics;
+  /** Combined cost of all subagent processes */
+  subagentCostUsd?: number;
+  /** Open the Session Report to see full cost breakdown */
+  onViewReport?: () => void;
   /** Phase information for phase selector */
   phaseInfo?: ContextPhaseInfo;
   /** Currently selected phase (null = current/latest) */

src/renderer/components/common/TokenUsageDisplay.tsx

@@ -11,6 +11,7 @@ import React, { useEffect, useRef, useState } from 'react';
 import { createPortal } from 'react-dom';
 
 import { COLOR_TEXT_MUTED, COLOR_TEXT_SECONDARY } from '@renderer/constants/cssVariables';
+import { formatCostUsd } from '@shared/utils/costFormatting';
 import { getModelColorClass } from '@shared/utils/modelParser';
 import {
   formatTokensCompact as formatTokens,
@@ -49,6 +50,8 @@ interface TokenUsageDisplayProps {
   phaseNumber?: number;
   /** Total number of phases in the session */
   totalPhases?: number;
+  /** Optional USD cost for this usage */
+  costUsd?: number;
 }
 
 /**
@@ -255,6 +258,7 @@ export const TokenUsageDisplay = ({
   contextStats,
   phaseNumber,
   totalPhases,
+  costUsd,
 }: Readonly<TokenUsageDisplayProps>): React.JSX.Element => {
   const totalTokens = inputTokens + cacheReadTokens + cacheCreationTokens + outputTokens;
   const formattedTotal = formatTokens(totalTokens);
@@ -513,6 +517,19 @@ export const TokenUsageDisplay = ({
                   </span>
                 </div>
 
+                {/* Cost (USD) - if available */}
+                {costUsd !== undefined && costUsd > 0 && (
+                  <div className="mt-1 flex items-center justify-between text-[10px]">
+                    <span style={{ color: COLOR_TEXT_SECONDARY }}>Cost (USD)</span>
+                    <span
+                      className="tabular-nums"
+                      style={{ color: 'var(--color-text-primary, var(--color-text))' }}
+                    >
+                      {formatCostUsd(costUsd)}
+                    </span>
+                  </div>
+                )}
+
                 {/* Visible Context Breakdown - expandable section */}
                 {contextStats &&
                   (contextStats.totalEstimatedTokens > 0 ||

src/renderer/components/dashboard/DashboardView.tsx

@@ -18,6 +18,7 @@ import {
   normalizePath,
   type TaskStatusCounts,
 } from '@renderer/utils/pathNormalize';
+import { formatShortcut } from '@renderer/utils/stringUtils';
 import { createLogger } from '@shared/utils/logger';
 import { useShallow } from 'zustand/react/shallow';
 
@@ -82,7 +83,11 @@ const CommandSearch = ({ value, onChange }: Readonly<CommandSearchProps>): React
         <button
           onClick={() => openCommandPalette()}
           className="flex shrink-0 items-center gap-1 transition-opacity hover:opacity-80"
-          title={selectedProjectId ? 'Search in sessions (⌘K)' : 'Search projects (⌘K)'}
+          title={
+            selectedProjectId
+              ? `Search in sessions (${formatShortcut('K')})`
+              : `Search projects (${formatShortcut('K')})`
+          }
         >
           <kbd className="flex h-5 items-center justify-center rounded border border-border bg-surface-overlay px-1.5 text-[10px] font-medium text-text-muted">
             <Command className="size-2.5" />

src/renderer/components/layout/CustomTitleBar.tsx

@@ -1,33 +1,36 @@
 /**
- * WindowsTitleBar - Conventional title bar for Windows when the native frame is hidden.
+ * CustomTitleBar - Conventional title bar for Windows and Linux when the native frame is hidden.
  *
  * Renders a draggable top strip with window controls (minimize, maximize/restore, close)
- * on the right, matching Windows conventions. Only shown in Electron on Windows (win32).
+ * on the right. Only shown in Electron on Windows or Linux (macOS uses native traffic lights).
  */
 
 import { useEffect, useState } from 'react';
 
 import { isElectronMode } from '@renderer/api';
-import { AppLogo } from '@renderer/components/common/AppLogo';
+import faviconUrl from '@renderer/favicon.png';
+import { useStore } from '@renderer/store';
 import { Minus, Square, X } from 'lucide-react';
 
 const TITLE_BAR_HEIGHT = 32;
 
-function isWindowsDesktop(): boolean {
+function needsCustomTitleBar(): boolean {
   if (!isElectronMode()) return false;
-  return window.navigator.userAgent.includes('Windows');
+  const ua = window.navigator.userAgent;
+  return ua.includes('Windows') || ua.includes('Linux');
 }
 
-export const WindowsTitleBar = (): React.JSX.Element | null => {
+export const CustomTitleBar = (): React.JSX.Element | null => {
   const [isMaximized, setIsMaximized] = useState(false);
-  const isWin = isWindowsDesktop();
+  const useNativeTitleBar = useStore((s) => s.appConfig?.general?.useNativeTitleBar ?? false);
+  const showTitleBar = needsCustomTitleBar() && !useNativeTitleBar;
   const api = typeof window !== 'undefined' ? window.electronAPI?.windowControls : null;
 
   useEffect(() => {
     if (api) void api.isMaximized().then(setIsMaximized);
   }, [api]);
 
-  if (!isWin || !api) return null;
+  if (!showTitleBar || !api) return null;
 
   const { minimize, maximize, close, isMaximized: getIsMaximized } = api;
 
@@ -50,15 +53,9 @@ export const WindowsTitleBar = (): React.JSX.Element | null => {
 
   return (
     <div className="flex shrink-0 select-none items-stretch" style={titleBarStyle}>
-      {/* Draggable area — app title optional */}
-      <div className="flex flex-1 items-center gap-2 pl-3" style={{ minWidth: 0 }}>
-        <AppLogo size={18} className="shrink-0" />
-        <span
-          className="truncate text-sm font-semibold"
-          style={{ color: 'var(--color-text-muted)' }}
-        >
-          Claude Agent Teams UI
-        </span>
+      {/* Draggable area — app icon */}
+      <div className="flex flex-1 items-center pl-3" style={{ minWidth: 0 }}>
+        <img src={faviconUrl} alt="" className="size-5 shrink-0 rounded-sm" draggable={false} />
       </div>
 
       {/* Window controls — no-drag so they receive clicks */}

src/renderer/components/layout/MoreMenu.tsx

@@ -0,0 +1,216 @@
+/**
+ * MoreMenu - Dropdown menu behind a "..." icon for less-frequent toolbar actions.
+ *
+ * Groups: Search, Export (session-only), Analyze (session-only), Settings.
+ * Closes on outside click or Escape.
+ */
+
+import React, { useCallback, useEffect, useRef, useState } from 'react';
+
+import { useStore } from '@renderer/store';
+import { triggerDownload } from '@renderer/utils/sessionExporter';
+import { formatShortcut } from '@renderer/utils/stringUtils';
+import { Activity, Braces, FileText, MoreHorizontal, Search, Settings, Type } from 'lucide-react';
+
+import type { SessionDetail } from '@renderer/types/data';
+import type { Tab } from '@renderer/types/tabs';
+import type { ExportFormat } from '@renderer/utils/sessionExporter';
+
+interface MoreMenuProps {
+  activeTab: Tab | undefined;
+  activeTabSessionDetail: SessionDetail | null;
+  activeTabId: string | null;
+}
+
+interface MenuItem {
+  id: string;
+  label: string;
+  icon: React.ComponentType<{ className?: string }>;
+  shortcut?: string;
+  onClick: () => void;
+}
+
+export const MoreMenu = ({
+  activeTab,
+  activeTabSessionDetail,
+  activeTabId,
+}: Readonly<MoreMenuProps>): React.JSX.Element => {
+  const [isOpen, setIsOpen] = useState(false);
+  const [buttonHover, setButtonHover] = useState(false);
+  const [hoveredId, setHoveredId] = useState<string | null>(null);
+  const containerRef = useRef<HTMLDivElement>(null);
+
+  const openCommandPalette = useStore((s) => s.openCommandPalette);
+  const openSettingsTab = useStore((s) => s.openSettingsTab);
+  const openSessionReport = useStore((s) => s.openSessionReport);
+
+  // Close on outside click
+  useEffect(() => {
+    if (!isOpen) return;
+
+    const handleClickOutside = (event: MouseEvent): void => {
+      if (containerRef.current && !containerRef.current.contains(event.target as Node)) {
+        setIsOpen(false);
+      }
+    };
+
+    document.addEventListener('mousedown', handleClickOutside);
+    return () => document.removeEventListener('mousedown', handleClickOutside);
+  }, [isOpen]);
+
+  // Close on Escape
+  useEffect(() => {
+    if (!isOpen) return;
+
+    const handleEscape = (event: KeyboardEvent): void => {
+      if (event.key === 'Escape') {
+        setIsOpen(false);
+      }
+    };
+
+    document.addEventListener('keydown', handleEscape);
+    return () => document.removeEventListener('keydown', handleEscape);
+  }, [isOpen]);
+
+  const handleExport = useCallback(
+    (format: ExportFormat) => {
+      if (activeTabSessionDetail) {
+        triggerDownload(activeTabSessionDetail, format);
+      }
+      setIsOpen(false);
+    },
+    [activeTabSessionDetail]
+  );
+
+  const isSessionWithData = activeTab?.type === 'session' && activeTabSessionDetail != null;
+
+  // Build menu sections
+  const topItems: MenuItem[] = [
+    {
+      id: 'search',
+      label: 'Search',
+      icon: Search,
+      shortcut: formatShortcut('K'),
+      onClick: () => {
+        openCommandPalette();
+        setIsOpen(false);
+      },
+    },
+  ];
+
+  const sessionItems: MenuItem[] = isSessionWithData
+    ? [
+        {
+          id: 'export-md',
+          label: 'Export as Markdown',
+          icon: FileText,
+          shortcut: '.md',
+          onClick: () => handleExport('markdown'),
+        },
+        {
+          id: 'export-json',
+          label: 'Export as JSON',
+          icon: Braces,
+          shortcut: '.json',
+          onClick: () => handleExport('json'),
+        },
+        {
+          id: 'export-txt',
+          label: 'Export as Plain Text',
+          icon: Type,
+          shortcut: '.txt',
+          onClick: () => handleExport('plaintext'),
+        },
+        {
+          id: 'analyze',
+          label: 'Analyze Session',
+          icon: Activity,
+          onClick: () => {
+            if (activeTabId) openSessionReport(activeTabId);
+            setIsOpen(false);
+          },
+        },
+      ]
+    : [];
+
+  const bottomItems: MenuItem[] = [
+    {
+      id: 'settings',
+      label: 'Settings',
+      icon: Settings,
+      shortcut: formatShortcut(','),
+      onClick: () => {
+        openSettingsTab();
+        setIsOpen(false);
+      },
+    },
+  ];
+
+  const renderItem = (item: MenuItem): React.JSX.Element => (
+    <button
+      key={item.id}
+      onClick={item.onClick}
+      onMouseEnter={() => setHoveredId(item.id)}
+      onMouseLeave={() => setHoveredId(null)}
+      className="flex w-full items-center gap-2.5 px-3 py-2 text-left text-xs transition-colors"
+      style={{
+        color: hoveredId === item.id ? 'var(--color-text)' : 'var(--color-text-secondary)',
+        backgroundColor: hoveredId === item.id ? 'var(--color-surface-raised)' : 'transparent',
+      }}
+    >
+      <item.icon className="size-3.5" />
+      <span className="flex-1">{item.label}</span>
+      {item.shortcut && (
+        <span className="text-[10px]" style={{ color: 'var(--color-text-muted)' }}>
+          {item.shortcut}
+        </span>
+      )}
+    </button>
+  );
+
+  const separator = (
+    <div className="my-0.5" style={{ borderBottom: '1px solid var(--color-border)' }} />
+  );
+
+  return (
+    <div ref={containerRef} className="relative">
+      {/* Trigger button */}
+      <button
+        onClick={() => setIsOpen(!isOpen)}
+        onMouseEnter={() => setButtonHover(true)}
+        onMouseLeave={() => setButtonHover(false)}
+        className="rounded-md p-2 transition-colors"
+        style={{
+          color: buttonHover || isOpen ? 'var(--color-text)' : 'var(--color-text-muted)',
+          backgroundColor: buttonHover || isOpen ? 'var(--color-surface-raised)' : 'transparent',
+        }}
+        title="More actions"
+      >
+        <MoreHorizontal className="size-4" />
+      </button>
+
+      {/* Dropdown menu */}
+      {isOpen && (
+        <div
+          className="absolute right-0 top-full z-50 mt-1 w-52 overflow-hidden rounded-md border shadow-lg"
+          style={{
+            backgroundColor: 'var(--color-surface-overlay)',
+            borderColor: 'var(--color-border)',
+          }}
+        >
+          {topItems.map(renderItem)}
+
+          {sessionItems.length > 0 && (
+            <>
+              {separator}
+              {sessionItems.map(renderItem)}
+            </>
+          )}
+
+          {separator}
+          {bottomItems.map(renderItem)}
+        </div>
+      )}
+    </div>
+  );
+};

src/renderer/components/layout/PaneContent.tsx

@@ -7,6 +7,7 @@ import { TabUIProvider } from '@renderer/contexts/TabUIContext';
 
 import { DashboardView } from '../dashboard/DashboardView';
 import { NotificationsView } from '../notifications/NotificationsView';
+import { SessionReportTab } from '../report/SessionReportTab';
 import { SettingsView } from '../settings/SettingsView';
 import { TeamDetailView } from '../team/TeamDetailView';
 import { TeamListView } from '../team/TeamListView';
@@ -51,6 +52,7 @@ export const PaneContent = ({ pane }: PaneContentProps): React.JSX.Element => {
                 <SessionTabContent tab={tab} isActive={isActive} />
               </TabUIProvider>
             )}
+            {tab.type === 'report' && <SessionReportTab tab={tab} />}
           </div>
         );
       })}

src/renderer/components/layout/SidebarHeader.tsx

@@ -17,7 +17,7 @@ import { isElectronMode } from '@renderer/api';
 import { HEADER_ROW1_HEIGHT, HEADER_ROW2_HEIGHT } from '@renderer/constants/layout';
 import { cn } from '@renderer/lib/utils';
 import { useStore } from '@renderer/store';
-import { truncateMiddle } from '@renderer/utils/stringUtils';
+import { formatShortcut, truncateMiddle } from '@renderer/utils/stringUtils';
 import { Check, ChevronDown, GitBranch, PanelLeft } from 'lucide-react';
 import { useShallow } from 'zustand/react/shallow';
 
@@ -329,7 +329,7 @@ export const SidebarHeader = (): React.JSX.Element => {
               backgroundColor: isCollapseHovered ? 'var(--color-surface-raised)' : 'transparent',
             } as React.CSSProperties
           }
-          title="Collapse sidebar (⌘B)"
+          title={`Collapse sidebar (${formatShortcut('B')})`}
         >
           <PanelLeft className="size-4" />
         </button>

src/renderer/components/layout/SortableTab.tsx

@@ -8,7 +8,17 @@ import { useCallback, useState } from 'react';
 import { useSortable } from '@dnd-kit/sortable';
 import { CSS } from '@dnd-kit/utilities';
 import { useStore } from '@renderer/store';
-import { Bell, FileText, LayoutDashboard, Pin, Search, Settings, Users, X } from 'lucide-react';
+import {
+  Activity,
+  Bell,
+  FileText,
+  LayoutDashboard,
+  Pin,
+  Search,
+  Settings,
+  Users,
+  X,
+} from 'lucide-react';
 import { useShallow } from 'zustand/react/shallow';
 
 import type { Tab } from '@renderer/types/tabs';
@@ -32,6 +42,7 @@ const TAB_ICONS = {
   session: FileText,
   teams: Users,
   team: Users,
+  report: Activity,
 } as const;
 
 export const SortableTab = ({
@@ -62,7 +73,8 @@ export const SortableTab = ({
     },
   });
 
-  const style: React.CSSProperties = {
+  const style = {
+    WebkitAppRegion: 'no-drag',
     transform: CSS.Transform.toString(transform),
     transition: isDragging ? 'none' : transition,
     opacity: isDragging ? 0.3 : 1,

src/renderer/components/layout/TabBar.tsx

@@ -14,11 +14,11 @@ import { horizontalListSortingStrategy, SortableContext } from '@dnd-kit/sortabl
 import { isElectronMode } from '@renderer/api';
 import { HEADER_ROW1_HEIGHT } from '@renderer/constants/layout';
 import { useStore } from '@renderer/store';
-import { Bell, PanelLeft, Plus, RefreshCw, Search, Settings, Users } from 'lucide-react';
+import { formatShortcut } from '@renderer/utils/stringUtils';
+import { Bell, PanelLeft, Plus, RefreshCw, Settings, Users } from 'lucide-react';
 import { useShallow } from 'zustand/react/shallow';
 
-import { ExportDropdown } from '../common/ExportDropdown';
-
+import { MoreMenu } from './MoreMenu';
 import { SortableTab } from './SortableTab';
 import { TabContextMenu } from './TabContextMenu';
 
@@ -41,7 +41,6 @@ export const TabBar = ({ paneId }: TabBarProps): React.JSX.Element => {
     openDashboard,
     fetchSessionDetail,
     fetchSessions,
-    openCommandPalette,
     unreadCount,
     openNotificationsTab,
     openTeamsTab,
@@ -69,7 +68,6 @@ export const TabBar = ({ paneId }: TabBarProps): React.JSX.Element => {
       openDashboard: s.openDashboard,
       fetchSessionDetail: s.fetchSessionDetail,
       fetchSessions: s.fetchSessions,
-      openCommandPalette: s.openCommandPalette,
       unreadCount: s.unreadCount,
       openNotificationsTab: s.openNotificationsTab,
       openTeamsTab: s.openTeamsTab,
@@ -104,7 +102,6 @@ export const TabBar = ({ paneId }: TabBarProps): React.JSX.Element => {
   const [expandHover, setExpandHover] = useState(false);
   const [refreshHover, setRefreshHover] = useState(false);
   const [newTabHover, setNewTabHover] = useState(false);
-  const [searchHover, setSearchHover] = useState(false);
   const [notificationsHover, setNotificationsHover] = useState(false);
   const [teamsHover, setTeamsHover] = useState(false);
   const [settingsHover, setSettingsHover] = useState(false);
@@ -271,8 +268,7 @@ export const TabBar = ({ paneId }: TabBarProps): React.JSX.Element => {
             sidebarCollapsed && isLeftmostPane
               ? 'var(--macos-traffic-light-padding-left, 72px)'
               : '8px',
-          WebkitAppRegion:
-            isElectronMode() && sidebarCollapsed && isLeftmostPane ? 'drag' : undefined,
+          WebkitAppRegion: isElectronMode() && isLeftmostPane ? 'drag' : undefined,
           backgroundColor: 'var(--color-surface)',
           borderBottom: '1px solid var(--color-border)',
           opacity: isFocused || paneCount === 1 ? 1 : 0.7,
@@ -299,15 +295,17 @@ export const TabBar = ({ paneId }: TabBarProps): React.JSX.Element => {
         </button>
       )}
 
-      {/* Tab list with horizontal scroll, sortable DnD, and droppable area */}
+      {/* Tab list with horizontal scroll, sortable DnD, and droppable area.
+          Capped at 75% so the drag spacer always has room to the right. */}
       <div
         ref={(el) => {
           scrollContainerRef.current = el;
           setDroppableRef(el);
         }}
-        className="scrollbar-none flex min-w-0 flex-1 items-center gap-1 overflow-x-auto"
+        className="scrollbar-none flex min-w-0 shrink items-center gap-1 overflow-x-auto"
         style={
           {
+            maxWidth: '75%',
             WebkitAppRegion: 'no-drag',
             outline: isDroppableOver ? '1px dashed var(--color-accent, #6366f1)' : 'none',
             outlineOffset: '-1px',
@@ -342,13 +340,25 @@ export const TabBar = ({ paneId }: TabBarProps): React.JSX.Element => {
             onMouseEnter={() => setRefreshHover(true)}
             onMouseLeave={() => setRefreshHover(false)}
             onClick={handleRefresh}
-            title="Refresh Session (Cmd+R)"
+            title={`Refresh Session (${formatShortcut('R')})`}
           >
             <RefreshCw className="size-4" />
           </button>
         )}
       </div>
 
+      {/* Drag spacer — fills empty space between tab list and action buttons.
+          Gives users a reliable window-drag target regardless of how many tabs are open.
+          Only applied on the leftmost pane in Electron to match the TabBar drag region logic. */}
+      <div
+        className="flex-1 self-stretch"
+        style={
+          {
+            WebkitAppRegion: isElectronMode() && isLeftmostPane ? 'drag' : undefined,
+          } as React.CSSProperties
+        }
+      />
+
       {/* Right side actions */}
       <div
         className="ml-2 flex shrink-0 items-center gap-1"
@@ -369,26 +379,6 @@ export const TabBar = ({ paneId }: TabBarProps): React.JSX.Element => {
           <Plus className="size-4" />
         </button>
 
-        {/* Search button (icon only) */}
-        <button
-          onClick={openCommandPalette}
-          onMouseEnter={() => setSearchHover(true)}
-          onMouseLeave={() => setSearchHover(false)}
-          className="rounded-md p-2 transition-colors"
-          style={{
-            color: searchHover ? 'var(--color-text)' : 'var(--color-text-muted)',
-            backgroundColor: searchHover ? 'var(--color-surface-raised)' : 'transparent',
-          }}
-          title="Search (Cmd+K)"
-        >
-          <Search className="size-4" />
-        </button>
-
-        {/* Export dropdown - show only for session tabs with loaded data */}
-        {activeTab?.type === 'session' && activeTabSessionDetail && (
-          <ExportDropdown sessionDetail={activeTabSessionDetail} />
-        )}
-
         {/* Notifications bell icon */}
         <button
           onClick={openNotificationsTab}
@@ -438,6 +428,13 @@ export const TabBar = ({ paneId }: TabBarProps): React.JSX.Element => {
         >
           <Settings className="size-4" />
         </button>
+
+        {/* More menu (Search, Export, Analyze, Settings) */}
+        <MoreMenu
+          activeTab={activeTab}
+          activeTabSessionDetail={activeTabSessionDetail}
+          activeTabId={activeTabId}
+        />
       </div>
 
       {/* Context menu */}

src/renderer/components/layout/TabContextMenu.tsx

@@ -7,6 +7,8 @@
 
 import { useEffect, useRef } from 'react';
 
+import { formatShortcut } from '@renderer/utils/stringUtils';
+
 interface TabContextMenuProps {
   x: number;
   y: number;
@@ -100,13 +102,17 @@ export const TabContextMenu = ({
           onClick={handleClick(onCloseSelectedTabs)}
         />
       ) : (
-        <MenuItem label="Close Tab" shortcut="⌘W" onClick={handleClick(onCloseTab)} />
+        <MenuItem
+          label="Close Tab"
+          shortcut={formatShortcut('W')}
+          onClick={handleClick(onCloseTab)}
+        />
       )}
       <MenuItem label="Close Other Tabs" onClick={handleClick(onCloseOtherTabs)} />
       <div className="mx-2 my-1 border-t" style={{ borderColor: 'var(--color-border)' }} />
       <MenuItem
         label="Split Right"
-        shortcut="⌘\"
+        shortcut={formatShortcut('\\')}
         onClick={handleClick(onSplitRight)}
         disabled={disableSplit}
       />
@@ -127,7 +133,11 @@ export const TabContextMenu = ({
         />
       )}
       <div className="mx-2 my-1 border-t" style={{ borderColor: 'var(--color-border)' }} />
-      <MenuItem label="Close All Tabs" shortcut="⇧⌘W" onClick={handleClick(onCloseAllTabs)} />
+      <MenuItem
+        label="Close All Tabs"
+        shortcut={formatShortcut('W', { shift: true })}
+        onClick={handleClick(onCloseAllTabs)}
+      />
     </div>
   );
 };

src/renderer/components/layout/TabbedLayout.tsx

@@ -17,9 +17,9 @@ import { UpdateDialog } from '../common/UpdateDialog';
 import { WorkspaceIndicator } from '../common/WorkspaceIndicator';
 import { CommandPalette } from '../search/CommandPalette';
 
+import { CustomTitleBar } from './CustomTitleBar';
 import { PaneContainer } from './PaneContainer';
 import { Sidebar } from './Sidebar';
-import { WindowsTitleBar } from './WindowsTitleBar';
 
 export const TabbedLayout = (): React.JSX.Element => {
   useKeyboardShortcuts();
@@ -38,7 +38,7 @@ export const TabbedLayout = (): React.JSX.Element => {
         { '--macos-traffic-light-padding-left': `${trafficLightPadding}px` } as React.CSSProperties
       }
     >
-      <WindowsTitleBar />
+      <CustomTitleBar />
       <UpdateBanner />
       <div className="flex flex-1 overflow-hidden">
         {/* Command Palette (Cmd+K) */}

src/renderer/components/report/AssessmentBadge.tsx

@@ -0,0 +1,78 @@
+import { useCallback, useEffect, useRef, useState } from 'react';
+import { createPortal } from 'react-dom';
+
+import {
+  assessmentColor,
+  assessmentExplanation,
+  assessmentLabel,
+} from '@renderer/utils/reportAssessments';
+
+import type { MetricKey } from '@renderer/utils/reportAssessments';
+
+interface AssessmentBadgeProps {
+  assessment: string;
+  metricKey?: MetricKey;
+}
+
+export const AssessmentBadge = ({ assessment, metricKey }: AssessmentBadgeProps) => {
+  const color = assessmentColor(assessment);
+  const explanation = metricKey ? assessmentExplanation(metricKey, assessment) : '';
+  const [showTooltip, setShowTooltip] = useState(false);
+  const [tooltipPos, setTooltipPos] = useState({ top: 0, left: 0 });
+  const badgeRef = useRef<HTMLSpanElement>(null);
+  const enterTimer = useRef<ReturnType<typeof setTimeout>>();
+  const leaveTimer = useRef<ReturnType<typeof setTimeout>>();
+
+  const handleMouseEnter = useCallback(() => {
+    if (!explanation) return;
+    clearTimeout(leaveTimer.current);
+    enterTimer.current = setTimeout(() => {
+      if (badgeRef.current) {
+        const rect = badgeRef.current.getBoundingClientRect();
+        setTooltipPos({ top: rect.bottom + 4, left: rect.left + rect.width / 2 });
+      }
+      setShowTooltip(true);
+    }, 200);
+  }, [explanation]);
+
+  const handleMouseLeave = useCallback(() => {
+    clearTimeout(enterTimer.current);
+    leaveTimer.current = setTimeout(() => setShowTooltip(false), 150);
+  }, []);
+
+  useEffect(() => {
+    return () => {
+      clearTimeout(enterTimer.current);
+      clearTimeout(leaveTimer.current);
+    };
+  }, []);
+
+  return (
+    <>
+      <span
+        ref={badgeRef}
+        className="rounded px-2 py-0.5 text-xs font-medium"
+        style={{ backgroundColor: `${color}20`, color }}
+        onMouseEnter={handleMouseEnter}
+        onMouseLeave={handleMouseLeave}
+      >
+        {assessmentLabel(assessment)}
+      </span>
+      {showTooltip &&
+        explanation &&
+        createPortal(
+          <div
+            className="pointer-events-none fixed z-50 max-w-60 rounded border border-border bg-surface-raised px-2.5 py-1.5 text-xs text-text-secondary shadow-lg"
+            style={{
+              top: tooltipPos.top,
+              left: tooltipPos.left,
+              transform: 'translateX(-50%)',
+            }}
+          >
+            {explanation}
+          </div>,
+          document.body
+        )}
+    </>
+  );
+};

src/renderer/components/report/ReportSection.tsx

@@ -0,0 +1,58 @@
+import { useEffect, useRef, useState } from 'react';
+
+import { ChevronDown, ChevronRight } from 'lucide-react';
+
+const sectionId = (title: string) =>
+  `report-section-${title.toLowerCase().replace(/[^a-z0-9]+/g, '-')}`;
+
+interface ReportSectionProps {
+  title: string;
+  icon: React.ComponentType<{ className?: string }>;
+  children: React.ReactNode;
+  defaultCollapsed?: boolean;
+}
+
+export const ReportSection = ({
+  title,
+  icon: Icon,
+  children,
+  defaultCollapsed = false,
+}: ReportSectionProps) => {
+  const [collapsed, setCollapsed] = useState(defaultCollapsed);
+  const ref = useRef<HTMLDivElement>(null);
+
+  useEffect(() => {
+    const el = ref.current;
+    if (!el) return;
+    const handler = () => {
+      setCollapsed(false);
+      el.scrollIntoView({ behavior: 'smooth', block: 'start' });
+    };
+    el.addEventListener('report-section-expand', handler);
+    return () => el.removeEventListener('report-section-expand', handler);
+  }, []);
+
+  return (
+    <div
+      ref={ref}
+      id={sectionId(title)}
+      className="rounded-lg border border-border bg-surface-raised"
+    >
+      <button
+        onClick={() => setCollapsed(!collapsed)}
+        className="flex w-full items-center gap-2 p-4 text-left"
+      >
+        {collapsed ? (
+          <ChevronRight className="size-4 text-text-muted" />
+        ) : (
+          <ChevronDown className="size-4 text-text-muted" />
+        )}
+        <Icon className="size-4 text-text-secondary" />
+        <span className="text-sm font-semibold text-text">{title}</span>
+      </button>
+      {!collapsed && <div className="border-t border-border px-4 pb-4 pt-3">{children}</div>}
+    </div>
+  );
+};
+
+export { sectionId };

src/renderer/components/report/SessionReportTab.tsx

@@ -0,0 +1,99 @@
+import { useMemo } from 'react';
+
+import { useStore } from '@renderer/store';
+import { computeTakeaways } from '@renderer/utils/reportAssessments';
+import { analyzeSession } from '@renderer/utils/sessionAnalyzer';
+
+import { CostSection } from './sections/CostSection';
+import { ErrorSection } from './sections/ErrorSection';
+import { FrictionSection } from './sections/FrictionSection';
+import { GitSection } from './sections/GitSection';
+import { InsightsSection } from './sections/InsightsSection';
+import { KeyTakeawaysSection } from './sections/KeyTakeawaysSection';
+import { OverviewSection } from './sections/OverviewSection';
+import { QualitySection } from './sections/QualitySection';
+import { SubagentSection } from './sections/SubagentSection';
+import { TimelineSection } from './sections/TimelineSection';
+import { TokenSection } from './sections/TokenSection';
+import { ToolSection } from './sections/ToolSection';
+
+import type { Tab } from '@renderer/types/tabs';
+
+interface SessionReportTabProps {
+  tab: Tab;
+}
+
+export const SessionReportTab = ({ tab }: SessionReportTabProps) => {
+  // Find session data from any session tab with matching sessionId
+  const sessionDetail = useStore((s) => {
+    const allTabs = s.paneLayout.panes.flatMap((p) => p.tabs);
+    const sourceTab = allTabs.find((t) => t.type === 'session' && t.sessionId === tab.sessionId);
+    return sourceTab ? s.tabSessionData[sourceTab.id]?.sessionDetail : null;
+  });
+
+  const report = useMemo(
+    () => (sessionDetail ? analyzeSession(sessionDetail) : null),
+    [sessionDetail]
+  );
+
+  const takeaways = useMemo(() => (report ? computeTakeaways(report) : []), [report]);
+
+  if (!report) {
+    return (
+      <div className="flex h-full items-center justify-center text-text-muted">
+        No session data available. Open the session tab first.
+      </div>
+    );
+  }
+
+  return (
+    <div className="h-full overflow-y-auto p-6" style={{ backgroundColor: 'var(--color-surface)' }}>
+      <h1 className="mb-6 text-lg font-semibold text-text">Session Analysis Report</h1>
+      <div className="flex flex-col gap-4">
+        {takeaways.length > 0 && <KeyTakeawaysSection takeaways={takeaways} />}
+        <OverviewSection data={report.overview} />
+        <CostSection
+          data={report.costAnalysis}
+          tokensByModel={report.tokenUsage.byModel}
+          commitCount={report.gitActivity.commitCount}
+          linesChanged={report.gitActivity.linesChanged}
+        />
+        <TokenSection data={report.tokenUsage} cacheEconomics={report.cacheEconomics} />
+        <ToolSection data={report.toolUsage} />
+        {report.subagentMetrics.count > 0 && (
+          <SubagentSection data={report.subagentMetrics} defaultCollapsed />
+        )}
+        {report.errors.errors.length > 0 && <ErrorSection data={report.errors} defaultCollapsed />}
+        <GitSection data={report.gitActivity} defaultCollapsed />
+        <FrictionSection
+          data={report.frictionSignals}
+          thrashing={report.thrashingSignals}
+          defaultCollapsed
+        />
+        <TimelineSection
+          idle={report.idleAnalysis}
+          modelSwitches={report.modelSwitches}
+          keyEvents={report.keyEvents}
+          defaultCollapsed
+        />
+        <QualitySection
+          prompt={report.promptQuality}
+          startup={report.startupOverhead}
+          testProgression={report.testProgression}
+          fileReadRedundancy={report.fileReadRedundancy}
+          defaultCollapsed
+        />
+        <InsightsSection
+          skills={report.skillsInvoked}
+          bash={report.bashCommands}
+          lifecycleTasks={report.lifecycleTasks}
+          userQuestions={report.userQuestions}
+          outOfScope={report.outOfScopeFindings}
+          agentTree={report.agentTree}
+          subagentsList={report.subagentsList}
+          defaultCollapsed
+        />
+      </div>
+    </div>
+  );
+};

src/renderer/components/report/sections/CostSection.tsx

@@ -0,0 +1,260 @@
+import { Fragment, useState } from 'react';
+
+import { getPricing } from '@renderer/utils/sessionAnalyzer';
+import { DollarSign } from 'lucide-react';
+
+import { AssessmentBadge } from '../AssessmentBadge';
+import { ReportSection, sectionId } from '../ReportSection';
+
+import type {
+  ModelPricing,
+  ModelTokenStats,
+  ReportCostAnalysis,
+} from '@renderer/types/sessionReport';
+
+const fmt = (v: number) => `$${v.toFixed(4)}`;
+const fmtK = (v: number) => (v >= 1000 ? `${(v / 1000).toFixed(1)}k` : String(v));
+const fmtRate = (v: number) => `$${v}`;
+const lineCost = (tokens: number, ratePerM: number) => (tokens * ratePerM) / 1_000_000;
+
+interface CostSectionProps {
+  data: ReportCostAnalysis;
+  tokensByModel: Record<string, ModelTokenStats>;
+  commitCount: number;
+  linesChanged: number;
+  defaultCollapsed?: boolean;
+}
+
+interface BreakdownLine {
+  label: string;
+  tokens: number;
+  ratePerM: number;
+}
+
+const CostBreakdownCard = ({
+  stats,
+  pricing,
+}: {
+  stats: ModelTokenStats;
+  pricing: ModelPricing;
+}) => {
+  const lines: BreakdownLine[] = [
+    { label: 'Input', tokens: stats.inputTokens, ratePerM: pricing.input },
+    { label: 'Output', tokens: stats.outputTokens, ratePerM: pricing.output },
+    { label: 'Cache Read', tokens: stats.cacheRead, ratePerM: pricing.cache_read },
+    { label: 'Cache Write', tokens: stats.cacheCreation, ratePerM: pricing.cache_creation },
+  ];
+  const total = lines.reduce((sum, l) => sum + lineCost(l.tokens, l.ratePerM), 0);
+
+  return (
+    <div className="rounded-md border border-border bg-surface-raised px-4 py-3">
+      <div className="mb-2 text-[10px] font-medium uppercase tracking-wider text-text-muted">
+        Cost Breakdown (per 1M tokens)
+      </div>
+      <div className="flex flex-col gap-1.5 font-mono text-xs">
+        {lines.map((l) => {
+          const cost = lineCost(l.tokens, l.ratePerM);
+          return (
+            <div key={l.label} className="flex items-baseline justify-between gap-4">
+              <span className="text-text-muted">{l.label}</span>
+              <span className="text-text-secondary">
+                {l.tokens.toLocaleString()} {'\u00D7'} {fmtRate(l.ratePerM)}/M = {fmt(cost)}
+              </span>
+            </div>
+          );
+        })}
+        <div className="mt-1 flex items-baseline justify-between gap-4 border-t border-border pt-1.5">
+          <span className="font-medium text-text">Total</span>
+          <span className="font-medium text-text">{fmt(total)}</span>
+        </div>
+      </div>
+    </div>
+  );
+};
+
+export const CostSection = ({
+  data,
+  tokensByModel,
+  commitCount,
+  linesChanged,
+  defaultCollapsed,
+}: CostSectionProps) => {
+  const [expandedModel, setExpandedModel] = useState<string | null>(null);
+  const modelEntries = Object.entries(data.costByModel).sort((a, b) => b[1] - a[1]);
+  const showStackedBar = data.subagentCostUsd > 0;
+  const parentPct =
+    showStackedBar && data.totalSessionCostUsd > 0
+      ? (data.parentCostUsd / data.totalSessionCostUsd) * 100
+      : 100;
+
+  return (
+    <ReportSection title="Cost Analysis" icon={DollarSign} defaultCollapsed={defaultCollapsed}>
+      <div className="mb-4 text-2xl font-bold text-text">{fmt(data.totalSessionCostUsd)}</div>
+
+      {/* Parent/Subagent stacked bar */}
+      {showStackedBar && (
+        <div className="mb-4">
+          <div className="mb-1.5 flex h-3 w-full overflow-hidden rounded-full">
+            <div
+              className="h-full"
+              style={{ width: `${parentPct}%`, backgroundColor: '#60a5fa' }}
+            />
+            <div
+              className="h-full"
+              style={{ width: `${100 - parentPct}%`, backgroundColor: '#c084fc' }}
+            />
+          </div>
+          <div className="flex gap-4 text-xs">
+            <div className="flex items-center gap-1.5">
+              <span
+                className="inline-block size-2 rounded-full"
+                style={{ backgroundColor: '#60a5fa' }}
+              />
+              <span className="text-text-secondary">Parent: {fmt(data.parentCostUsd)}</span>
+            </div>
+            <div className="flex items-center gap-1.5">
+              <span
+                className="inline-block size-2 rounded-full"
+                style={{ backgroundColor: '#c084fc' }}
+              />
+              <span className="text-text-secondary">Subagent: {fmt(data.subagentCostUsd)}</span>
+            </div>
+          </div>
+        </div>
+      )}
+
+      <div className="mb-4 grid grid-cols-2 gap-3 sm:grid-cols-4">
+        {!showStackedBar && (
+          <>
+            <div>
+              <div className="text-xs text-text-muted">Parent Cost</div>
+              <div className="text-sm font-medium text-text">{fmt(data.parentCostUsd)}</div>
+            </div>
+            <div>
+              <div className="text-xs text-text-muted">Subagent Cost</div>
+              <div className="text-sm font-medium text-text">{fmt(data.subagentCostUsd)}</div>
+            </div>
+          </>
+        )}
+        <div>
+          <div className="text-xs text-text-muted">Per Commit</div>
+          <div className="text-[10px] text-text-muted">
+            {commitCount > 0 ? (
+              <>
+                total cost {'\u00F7'} {commitCount} commit{commitCount !== 1 ? 's' : ''}
+              </>
+            ) : (
+              'no commits'
+            )}
+          </div>
+          <div className="flex items-center gap-2">
+            <span className="text-sm font-medium text-text">
+              {data.costPerCommit != null ? fmt(data.costPerCommit) : 'N/A'}
+            </span>
+            {data.costPerCommitAssessment && (
+              <AssessmentBadge
+                assessment={data.costPerCommitAssessment}
+                metricKey="costPerCommit"
+              />
+            )}
+          </div>
+        </div>
+        <div>
+          <div className="text-xs text-text-muted">Per Line Changed</div>
+          <div className="text-[10px] text-text-muted">
+            {linesChanged > 0 ? (
+              <>
+                total cost {'\u00F7'} {linesChanged.toLocaleString()} line
+                {linesChanged !== 1 ? 's' : ''}
+              </>
+            ) : (
+              'no lines changed'
+            )}
+          </div>
+          <div className="flex items-center gap-2">
+            <span className="text-sm font-medium text-text">
+              {data.costPerLineChanged != null ? `$${data.costPerLineChanged.toFixed(6)}` : 'N/A'}
+            </span>
+            {data.costPerLineAssessment && (
+              <AssessmentBadge assessment={data.costPerLineAssessment} metricKey="costPerLine" />
+            )}
+          </div>
+        </div>
+      </div>
+
+      {modelEntries.length > 0 && (
+        <table className="w-full text-xs">
+          <thead>
+            <tr className="border-b border-border text-left text-text-muted">
+              <th className="pb-2 pr-4">Model</th>
+              <th className="pb-2 pr-4 text-right">Input</th>
+              <th className="pb-2 pr-4 text-right">Output</th>
+              <th className="pb-2 pr-4 text-right">Cache Read</th>
+              <th className="pb-2 pr-4 text-right">Cache Write</th>
+              <th className="pb-2 pr-4 text-right">Cost</th>
+            </tr>
+          </thead>
+          <tbody>
+            {modelEntries.map(([model, cost]) => {
+              const stats = tokensByModel[model];
+              // Don't allow expansion for the synthetic aggregated row — getPricing
+              // would return wrong default rates for a non-model label.
+              const isAggregateRow = model === 'Subagents (combined)';
+              const isExpanded = expandedModel === model && !!stats && !isAggregateRow;
+              const pricing = isAggregateRow ? null : getPricing(model);
+              return (
+                <Fragment key={model}>
+                  <tr
+                    className={`border-border/50 border-b ${stats ? 'hover:bg-surface-raised/50 cursor-pointer' : ''}`}
+                    onClick={() => {
+                      if (isAggregateRow) {
+                        const el = document.getElementById(sectionId('Subagents'));
+                        if (el) {
+                          el.scrollIntoView({ behavior: 'smooth' });
+                          el.dispatchEvent(new CustomEvent('report-section-expand'));
+                        }
+                      } else if (stats) {
+                        setExpandedModel(isExpanded ? null : model);
+                      }
+                    }}
+                  >
+                    <td className="py-1.5 pr-4 text-text">
+                      {isAggregateRow ? (
+                        <span className="mr-1.5 inline-block w-3 text-text-muted">{'\u2192'}</span>
+                      ) : (
+                        <span className="mr-1.5 inline-block w-3 text-text-muted">
+                          {stats ? (isExpanded ? '\u25BC' : '\u25B6') : ''}
+                        </span>
+                      )}
+                      {model}
+                    </td>
+                    <td className="py-1.5 pr-4 text-right text-text-secondary">
+                      {stats ? fmtK(stats.inputTokens) : '—'}
+                    </td>
+                    <td className="py-1.5 pr-4 text-right text-text-secondary">
+                      {stats ? fmtK(stats.outputTokens) : '—'}
+                    </td>
+                    <td className="py-1.5 pr-4 text-right text-text-secondary">
+                      {stats ? fmtK(stats.cacheRead) : '—'}
+                    </td>
+                    <td className="py-1.5 pr-4 text-right text-text-secondary">
+                      {stats ? fmtK(stats.cacheCreation) : '—'}
+                    </td>
+                    <td className="py-1.5 pr-4 text-right font-medium text-text">{fmt(cost)}</td>
+                  </tr>
+                  {isExpanded && stats && pricing && (
+                    <tr>
+                      <td colSpan={6} className="px-4 pb-3 pt-1">
+                        <CostBreakdownCard stats={stats} pricing={pricing} />
+                      </td>
+                    </tr>
+                  )}
+                </Fragment>
+              );
+            })}
+          </tbody>
+        </table>
+      )}
+    </ReportSection>
+  );
+};

src/renderer/components/report/sections/ErrorSection.tsx

@@ -0,0 +1,103 @@
+import { useState } from 'react';
+
+import { AlertTriangle, ChevronDown, ChevronRight } from 'lucide-react';
+
+import { ReportSection } from '../ReportSection';
+
+import type { ReportErrors, ToolError } from '@renderer/types/sessionReport';
+
+interface ErrorItemProps {
+  error: ToolError;
+}
+
+const ErrorItem = ({ error }: ErrorItemProps) => {
+  const [expanded, setExpanded] = useState(false);
+
+  return (
+    <div className="border-border/50 rounded border bg-surface p-2">
+      <button
+        onClick={() => setExpanded(!expanded)}
+        className="flex w-full items-center gap-2 text-left text-xs"
+      >
+        {expanded ? (
+          <ChevronDown className="size-3 text-text-muted" />
+        ) : (
+          <ChevronRight className="size-3 text-text-muted" />
+        )}
+        <span className="font-medium text-text">{error.tool}</span>
+        {error.isPermissionDenial && (
+          <span
+            className="rounded px-1.5 py-0.5 text-[10px] font-medium"
+            style={{
+              backgroundColor: 'color-mix(in srgb, var(--assess-danger) 15%, transparent)',
+              color: 'var(--assess-danger)',
+            }}
+          >
+            Permission Denied
+          </span>
+        )}
+        <span className="ml-auto text-text-muted">msg #{error.messageIndex}</span>
+      </button>
+      {expanded && (
+        <div className="mt-2 flex flex-col gap-1.5">
+          {error.inputPreview && (
+            <div className="rounded bg-surface-raised p-2">
+              <div className="mb-1 text-[10px] font-medium uppercase tracking-wider text-text-muted">
+                Input
+              </div>
+              <div className="whitespace-pre-wrap break-words font-mono text-xs text-text-secondary">
+                {error.inputPreview}
+              </div>
+            </div>
+          )}
+          <div className="rounded bg-surface-raised p-2">
+            <div className="mb-1 text-[10px] font-medium uppercase tracking-wider text-text-muted">
+              Error
+            </div>
+            <div
+              className="whitespace-pre-wrap break-words text-xs"
+              style={{ color: 'var(--assess-danger)' }}
+            >
+              {error.error}
+            </div>
+          </div>
+        </div>
+      )}
+    </div>
+  );
+};
+
+interface ErrorSectionProps {
+  data: ReportErrors;
+  defaultCollapsed?: boolean;
+}
+
+export const ErrorSection = ({ data, defaultCollapsed }: ErrorSectionProps) => {
+  return (
+    <ReportSection title="Errors" icon={AlertTriangle} defaultCollapsed={defaultCollapsed}>
+      <div className="mb-3 flex items-center gap-3">
+        <span
+          className="rounded px-2 py-0.5 text-xs font-medium"
+          style={{
+            backgroundColor: 'color-mix(in srgb, var(--assess-danger) 15%, transparent)',
+            color: 'var(--assess-danger)',
+          }}
+        >
+          {data.errors.length} error{data.errors.length !== 1 ? 's' : ''}
+        </span>
+        {data.permissionDenials.count > 0 && (
+          <span className="text-xs text-text-muted">
+            {data.permissionDenials.count} permission denial
+            {data.permissionDenials.count !== 1 ? 's' : ''}
+          </span>
+        )}
+      </div>
+
+      <div className="flex flex-col gap-2">
+        {data.errors.map((error, idx) => (
+          <ErrorItem key={idx} error={error} />
+        ))}
+      </div>
+    </ReportSection>
+  );
+};

src/renderer/components/report/sections/FrictionSection.tsx

@@ -0,0 +1,97 @@
+import { severityColor } from '@renderer/utils/reportAssessments';
+import { MessageSquareWarning } from 'lucide-react';
+
+import { AssessmentBadge } from '../AssessmentBadge';
+import { ReportSection } from '../ReportSection';
+
+import type { ReportFrictionSignals, ReportThrashingSignals } from '@renderer/types/sessionReport';
+
+interface FrictionSectionProps {
+  data: ReportFrictionSignals;
+  thrashing: ReportThrashingSignals;
+  defaultCollapsed?: boolean;
+}
+
+export const FrictionSection = ({ data, thrashing, defaultCollapsed }: FrictionSectionProps) => {
+  const frictionSeverity =
+    data.frictionRate <= 0.1 ? 'good' : data.frictionRate <= 0.25 ? 'warning' : 'danger';
+  const frictionColor = severityColor(frictionSeverity);
+
+  return (
+    <ReportSection
+      title="Friction Signals"
+      icon={MessageSquareWarning}
+      defaultCollapsed={defaultCollapsed}
+    >
+      <div className="mb-4 flex items-center gap-3">
+        <span
+          className="rounded px-2 py-0.5 text-xs font-medium"
+          style={{
+            backgroundColor: `color-mix(in srgb, ${frictionColor} 12%, transparent)`,
+            color: frictionColor,
+          }}
+        >
+          Friction Rate: {(data.frictionRate * 100).toFixed(1)}%
+        </span>
+        <span className="text-xs text-text-muted">
+          {data.correctionCount} correction{data.correctionCount !== 1 ? 's' : ''}
+        </span>
+      </div>
+
+      {data.corrections.length > 0 && (
+        <div className="mb-4">
+          <div className="mb-2 text-xs font-medium text-text-muted">Corrections</div>
+          <div className="flex flex-col gap-1">
+            {data.corrections.map((corr, idx) => (
+              <div key={idx} className="flex items-start gap-2 rounded px-2 py-1 text-xs">
+                <span
+                  className="shrink-0 rounded px-1.5 py-0.5 font-mono text-[10px]"
+                  style={{
+                    backgroundColor: 'color-mix(in srgb, var(--assess-warning) 15%, transparent)',
+                    color: 'var(--assess-warning)',
+                  }}
+                >
+                  {corr.keyword}
+                </span>
+                <span className="truncate text-text-secondary">{corr.preview}</span>
+              </div>
+            ))}
+          </div>
+        </div>
+      )}
+
+      {(thrashing.bashNearDuplicates.length > 0 || thrashing.editReworkFiles.length > 0) && (
+        <div>
+          <div className="mb-2 flex items-center gap-2">
+            <span className="text-xs font-medium text-text-muted">Thrashing Signals</span>
+            <AssessmentBadge assessment={thrashing.thrashingAssessment} metricKey="thrashing" />
+          </div>
+
+          {thrashing.bashNearDuplicates.length > 0 && (
+            <div className="mb-2">
+              <div className="mb-1 text-xs text-text-muted">Repeated Bash Commands</div>
+              {thrashing.bashNearDuplicates.map((dup, idx) => (
+                <div key={idx} className="flex items-center gap-2 px-2 py-0.5 text-xs">
+                  <span className="text-text-muted">{dup.count}x</span>
+                  <code className="truncate text-text-secondary">{dup.prefix}</code>
+                </div>
+              ))}
+            </div>
+          )}
+
+          {thrashing.editReworkFiles.length > 0 && (
+            <div>
+              <div className="mb-1 text-xs text-text-muted">Reworked Files (3+ edits)</div>
+              {thrashing.editReworkFiles.map((file, idx) => (
+                <div key={idx} className="flex items-center gap-2 px-2 py-0.5 text-xs">
+                  <span className="text-text-muted">{file.editIndices.length}x</span>
+                  <span className="truncate text-text-secondary">{file.filePath}</span>
+                </div>
+              ))}
+            </div>
+          )}
+        </div>
+      )}
+    </ReportSection>
+  );
+};

src/renderer/components/report/sections/GitSection.tsx

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+import { GitBranch } from 'lucide-react';
+
+import { ReportSection } from '../ReportSection';
+
+import type { ReportGitActivity } from '@renderer/types/sessionReport';
+
+interface GitSectionProps {
+  data: ReportGitActivity;
+  defaultCollapsed?: boolean;
+}
+
+export const GitSection = ({ data, defaultCollapsed }: GitSectionProps) => {
+  return (
+    <ReportSection title="Git Activity" icon={GitBranch} defaultCollapsed={defaultCollapsed}>
+      <div className="mb-4 grid grid-cols-2 gap-3 sm:grid-cols-4">
+        <div>
+          <div className="text-xs text-text-muted">Commits</div>
+          <div className="text-sm font-medium text-text">{data.commitCount}</div>
+        </div>
+        <div>
+          <div className="text-xs text-text-muted">Pushes</div>
+          <div className="text-sm font-medium text-text">{data.pushCount}</div>
+        </div>
+        <div>
+          <div className="text-xs text-text-muted">Lines Added</div>
+          <div className="text-sm font-medium" style={{ color: 'var(--assess-good)' }}>
+            +{data.linesAdded.toLocaleString()}
+          </div>
+        </div>
+        <div>
+          <div className="text-xs text-text-muted">Lines Removed</div>
+          <div className="text-sm font-medium" style={{ color: 'var(--assess-danger)' }}>
+            -{data.linesRemoved.toLocaleString()}
+          </div>
+        </div>
+      </div>
+
+      {data.commits.length > 0 && (
+        <div>
+          <div className="mb-2 text-xs font-medium text-text-muted">Commits</div>
+          <div className="flex flex-col gap-1">
+            {data.commits.map((commit, idx) => (
+              <div
+                key={idx}
+                className="flex items-center gap-2 rounded px-2 py-1 text-xs text-text"
+              >
+                <span className="text-text-muted">#{commit.messageIndex}</span>
+                <span className="truncate">{commit.messagePreview}</span>
+              </div>
+            ))}
+          </div>
+        </div>
+      )}
+
+      {data.branchCreations.length > 0 && (
+        <div className="mt-3">
+          <div className="mb-1 text-xs font-medium text-text-muted">Branches Created</div>
+          <div className="flex flex-wrap gap-1">
+            {data.branchCreations.map((branch, idx) => (
+              <span
+                key={idx}
+                className="rounded bg-surface px-2 py-0.5 text-xs text-text-secondary"
+              >
+                {branch}
+              </span>
+            ))}
+          </div>
+        </div>
+      )}
+    </ReportSection>
+  );
+};

src/renderer/components/report/sections/InsightsSection.tsx

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+import { Lightbulb } from 'lucide-react';
+
+import { ReportSection } from '../ReportSection';
+
+import type {
+  OutOfScopeFindings,
+  ReportAgentTree,
+  ReportBashCommands,
+  SkillInvocation,
+  SubagentBasicEntry,
+  UserQuestion,
+} from '@renderer/types/sessionReport';
+
+interface InsightsSectionProps {
+  skills: SkillInvocation[];
+  bash: ReportBashCommands;
+  lifecycleTasks: string[];
+  userQuestions: UserQuestion[];
+  outOfScope: OutOfScopeFindings[];
+  agentTree: ReportAgentTree;
+  subagentsList: SubagentBasicEntry[];
+  defaultCollapsed?: boolean;
+}
+
+export const InsightsSection = ({
+  skills,
+  bash,
+  lifecycleTasks,
+  userQuestions,
+  outOfScope,
+  agentTree,
+  subagentsList,
+  defaultCollapsed,
+}: InsightsSectionProps) => {
+  return (
+    <ReportSection title="Session Insights" icon={Lightbulb} defaultCollapsed={defaultCollapsed}>
+      {/* Skills invoked */}
+      {skills.length > 0 && (
+        <div className="mb-4">
+          <div className="mb-2 text-xs font-medium text-text-muted">
+            Skills Invoked ({skills.length})
+          </div>
+          <div className="flex flex-col gap-1">
+            {skills.map((s, idx) => (
+              <div key={idx} className="flex items-center gap-2 px-2 py-0.5 text-xs">
+                <span className="font-mono text-text">{s.skill}</span>
+                {s.argsPreview && <span className="truncate text-text-muted">{s.argsPreview}</span>}
+              </div>
+            ))}
+          </div>
+        </div>
+      )}
+
+      {/* Bash commands */}
+      <div className="mb-4">
+        <div className="mb-2 text-xs font-medium text-text-muted">Bash Commands</div>
+        <div className="grid grid-cols-2 gap-3 sm:grid-cols-3">
+          <div>
+            <div className="text-xs text-text-muted">Total</div>
+            <div className="text-sm font-medium text-text">{bash.total}</div>
+          </div>
+          <div>
+            <div className="text-xs text-text-muted">Unique</div>
+            <div className="text-sm font-medium text-text">{bash.unique}</div>
+          </div>
+          <div>
+            <div className="text-xs text-text-muted">Repeated</div>
+            <div className="text-sm font-medium text-text">{Object.keys(bash.repeated).length}</div>
+          </div>
+        </div>
+        {Object.keys(bash.repeated).length > 0 && (
+          <div className="mt-2 flex flex-col gap-1">
+            {Object.entries(bash.repeated)
+              .slice(0, 10)
+              .map(([cmd, count], idx) => (
+                <div key={idx} className="flex items-center gap-2 px-2 py-0.5 text-xs">
+                  <span className="font-mono text-text-muted">{count}x</span>
+                  <span className="truncate font-mono text-text-secondary">{cmd}</span>
+                </div>
+              ))}
+          </div>
+        )}
+      </div>
+
+      {/* Task tool subagent list */}
+      {subagentsList.length > 0 && (
+        <div className="mb-4">
+          <div className="mb-2 text-xs font-medium text-text-muted">
+            Task Dispatches ({subagentsList.length})
+          </div>
+          <div className="flex flex-col gap-1">
+            {subagentsList.map((s, idx) => (
+              <div key={idx} className="flex items-center gap-2 px-2 py-0.5 text-xs">
+                <span className="rounded bg-surface-raised px-1.5 py-0.5 text-text-muted">
+                  {s.subagentType}
+                </span>
+                <span className="truncate text-text">{s.description}</span>
+                {s.runInBackground && <span className="text-text-muted">(background)</span>}
+              </div>
+            ))}
+          </div>
+        </div>
+      )}
+
+      {/* Lifecycle tasks */}
+      {lifecycleTasks.length > 0 && (
+        <div className="mb-4">
+          <div className="mb-2 text-xs font-medium text-text-muted">
+            Tasks Created ({lifecycleTasks.length})
+          </div>
+          <div className="flex flex-col gap-1">
+            {lifecycleTasks.map((task, idx) => (
+              <div key={idx} className="px-2 py-0.5 text-xs text-text-secondary">
+                {task}
+              </div>
+            ))}
+          </div>
+        </div>
+      )}
+
+      {/* User questions */}
+      {userQuestions.length > 0 && (
+        <div className="mb-4">
+          <div className="mb-2 text-xs font-medium text-text-muted">
+            Questions Asked ({userQuestions.length})
+          </div>
+          <div className="flex flex-col gap-2">
+            {userQuestions.map((q, idx) => (
+              <div key={idx} className="rounded-md bg-surface-raised px-3 py-2">
+                <div className="text-xs text-text">{q.question}</div>
+                {q.options.length > 0 && (
+                  <div className="mt-1 flex flex-wrap gap-1">
+                    {q.options.map((opt, optIdx) => (
+                      <span
+                        key={optIdx}
+                        className="rounded px-1.5 py-0.5 text-xs text-text-muted"
+                        style={{ backgroundColor: 'var(--color-surface-overlay)' }}
+                      >
+                        {opt}
+                      </span>
+                    ))}
+                  </div>
+                )}
+              </div>
+            ))}
+          </div>
+        </div>
+      )}
+
+      {/* Agent tree */}
+      {agentTree.agentCount > 0 && (
+        <div className="mb-4">
+          <div className="mb-2 text-xs font-medium text-text-muted">
+            Agent Tree ({agentTree.agentCount} agent{agentTree.agentCount !== 1 ? 's' : ''})
+            {agentTree.hasTeamMode && (
+              <span className="ml-2 rounded px-1.5 py-0.5 text-xs" style={{ color: '#60a5fa' }}>
+                Team Mode
+              </span>
+            )}
+          </div>
+          {agentTree.teamNames.length > 0 && (
+            <div className="mb-2 text-xs text-text-muted">
+              Teams: {agentTree.teamNames.join(', ')}
+            </div>
+          )}
+          <div className="flex flex-col gap-1">
+            {agentTree.agents.map((agent, idx) => (
+              <div key={idx} className="flex items-center gap-2 px-2 py-0.5 text-xs">
+                <span className="rounded bg-surface-raised px-1.5 py-0.5 text-text-muted">
+                  {agent.agentType}
+                </span>
+                <span className="truncate font-mono text-text-secondary">
+                  {agent.agentId.slice(0, 12)}...
+                </span>
+              </div>
+            ))}
+          </div>
+        </div>
+      )}
+
+      {/* Out-of-scope findings */}
+      {outOfScope.length > 0 && (
+        <div>
+          <div className="mb-2 text-xs font-medium text-text-muted">
+            Out-of-Scope Findings ({outOfScope.length})
+          </div>
+          <div className="flex flex-col gap-2">
+            {outOfScope.map((f, idx) => (
+              <div key={idx} className="rounded-md bg-surface-raised px-3 py-2">
+                <span
+                  className="mr-2 rounded px-1.5 py-0.5 text-xs"
+                  style={{
+                    backgroundColor: 'color-mix(in srgb, var(--assess-warning) 12%, transparent)',
+                    color: 'var(--assess-warning)',
+                  }}
+                >
+                  {f.keyword}
+                </span>
+                <span className="text-xs text-text-secondary">{f.snippet}</span>
+              </div>
+            ))}
+          </div>
+        </div>
+      )}
+    </ReportSection>
+  );
+};

src/renderer/components/report/sections/KeyTakeawaysSection.tsx

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+import { severityColor } from '@renderer/utils/reportAssessments';
+import { AlertTriangle, CheckCircle, ChevronRight, Info, XCircle } from 'lucide-react';
+
+import { sectionId } from '../ReportSection';
+
+import type { Severity, Takeaway } from '@renderer/utils/reportAssessments';
+
+const SEVERITY_ICONS: Record<Severity, React.ComponentType<{ className?: string }>> = {
+  danger: XCircle,
+  warning: AlertTriangle,
+  good: CheckCircle,
+  neutral: Info,
+};
+
+const scrollToSection = (sectionTitle: string) => {
+  const el = document.getElementById(sectionId(sectionTitle));
+  if (!el) return;
+  el.dispatchEvent(new CustomEvent('report-section-expand'));
+};
+
+interface KeyTakeawaysSectionProps {
+  takeaways: Takeaway[];
+}
+
+export const KeyTakeawaysSection = ({ takeaways }: KeyTakeawaysSectionProps) => {
+  return (
+    <div className="rounded-lg border border-border bg-surface-raised p-4">
+      <div className="mb-3 text-sm font-semibold text-text">Key Takeaways</div>
+      <div className="flex flex-col gap-2">
+        {takeaways.map((t, idx) => {
+          const Icon = SEVERITY_ICONS[t.severity];
+          const color = severityColor(t.severity);
+          return (
+            <button
+              key={idx}
+              type="button"
+              onClick={() => scrollToSection(t.sectionTitle)}
+              className="flex w-full items-start gap-3 rounded-md border-l-2 bg-surface px-3 py-2 text-left transition-colors hover:bg-surface-raised"
+              style={{ borderLeftColor: color }}
+            >
+              <span className="mt-0.5 shrink-0" style={{ color }}>
+                <Icon className="size-4" />
+              </span>
+              <div className="min-w-0 flex-1">
+                <div className="text-sm font-medium text-text">{t.title}</div>
+                <div className="text-xs text-text-secondary">{t.detail}</div>
+              </div>
+              <ChevronRight className="mt-0.5 size-4 shrink-0 text-text-muted" />
+            </button>
+          );
+        })}
+      </div>
+    </div>
+  );
+};

src/renderer/components/report/sections/OverviewSection.tsx

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+import { assessmentColor } from '@renderer/utils/reportAssessments';
+import { Activity } from 'lucide-react';
+
+import { ReportSection } from '../ReportSection';
+
+import type { ReportOverview } from '@renderer/types/sessionReport';
+
+interface OverviewSectionProps {
+  data: ReportOverview;
+}
+
+export const OverviewSection = ({ data }: OverviewSectionProps) => {
+  return (
+    <ReportSection title="Overview" icon={Activity}>
+      <div className="mb-3 truncate text-xs text-text-muted">{data.firstMessage}</div>
+      <div className="grid grid-cols-2 gap-3 sm:grid-cols-4">
+        <div>
+          <div className="text-xs text-text-muted">Duration</div>
+          <div className="text-sm font-medium text-text">{data.durationHuman}</div>
+        </div>
+        <div>
+          <div className="text-xs text-text-muted">Messages</div>
+          <div className="text-sm font-medium text-text">{data.totalMessages.toLocaleString()}</div>
+        </div>
+        <div>
+          <div className="text-xs text-text-muted">Context Usage</div>
+          <div
+            className="text-sm font-medium"
+            style={{ color: assessmentColor(data.contextAssessment) }}
+          >
+            {data.contextConsumptionPct != null ? `${data.contextConsumptionPct}%` : 'N/A'}
+            {data.contextAssessment && (
+              <span className="ml-1 text-xs">({data.contextAssessment})</span>
+            )}
+          </div>
+        </div>
+        <div>
+          <div className="text-xs text-text-muted">Compactions</div>
+          <div className="text-sm font-medium text-text">{data.compactionCount}</div>
+        </div>
+        <div>
+          <div className="text-xs text-text-muted">Branch</div>
+          <div className="truncate text-sm font-medium text-text">{data.gitBranch}</div>
+        </div>
+        <div>
+          <div className="text-xs text-text-muted">Subagents</div>
+          <div className="text-sm font-medium text-text">{data.hasSubagents ? 'Yes' : 'No'}</div>
+        </div>
+        <div>
+          <div className="text-xs text-text-muted">Project</div>
+          <div className="truncate text-sm font-medium text-text" title={data.projectPath}>
+            {data.projectPath}
+          </div>
+        </div>
+        <div>
+          <div className="text-xs text-text-muted">Session ID</div>
+          <div className="truncate text-sm font-medium text-text" title={data.sessionId}>
+            {data.sessionId.slice(0, 12)}...
+          </div>
+        </div>
+      </div>
+    </ReportSection>
+  );
+};

src/renderer/components/report/sections/QualitySection.tsx

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+import { severityColor } from '@renderer/utils/reportAssessments';
+import { BarChart3 } from 'lucide-react';
+
+import { AssessmentBadge } from '../AssessmentBadge';
+import { ReportSection } from '../ReportSection';
+
+import type {
+  ReportFileReadRedundancy,
+  ReportPromptQuality,
+  ReportStartupOverhead,
+  ReportTestProgression,
+} from '@renderer/types/sessionReport';
+
+interface QualitySectionProps {
+  prompt: ReportPromptQuality;
+  startup: ReportStartupOverhead;
+  testProgression: ReportTestProgression;
+  fileReadRedundancy: ReportFileReadRedundancy;
+  defaultCollapsed?: boolean;
+}
+
+export const QualitySection = ({
+  prompt,
+  startup,
+  testProgression,
+  fileReadRedundancy,
+  defaultCollapsed,
+}: QualitySectionProps) => {
+  return (
+    <ReportSection title="Quality Signals" icon={BarChart3} defaultCollapsed={defaultCollapsed}>
+      {/* Prompt quality */}
+      <div className="mb-4">
+        <div className="mb-2 text-xs font-medium text-text-muted">Prompt Quality</div>
+        <div className="mb-2 flex items-center gap-2">
+          <AssessmentBadge assessment={prompt.assessment} metricKey="promptQuality" />
+        </div>
+        <div className="text-xs text-text-secondary">{prompt.note}</div>
+        <div className="mt-2 grid grid-cols-2 gap-3 sm:grid-cols-4">
+          <div>
+            <div className="text-xs text-text-muted">First Message</div>
+            <div className="text-sm font-medium text-text">
+              {prompt.firstMessageLengthChars.toLocaleString()} chars
+            </div>
+          </div>
+          <div>
+            <div className="text-xs text-text-muted">User Messages</div>
+            <div className="text-sm font-medium text-text">{prompt.userMessageCount}</div>
+          </div>
+          <div>
+            <div className="text-xs text-text-muted">Corrections</div>
+            <div className="text-sm font-medium text-text">{prompt.correctionCount}</div>
+          </div>
+          <div>
+            <div className="text-xs text-text-muted">Friction Rate</div>
+            <div className="text-sm font-medium text-text">
+              {(prompt.frictionRate * 100).toFixed(1)}%
+            </div>
+          </div>
+        </div>
+      </div>
+
+      {/* Startup overhead */}
+      <div className="mb-4">
+        <div className="mb-2 flex items-center gap-2">
+          <span className="text-xs font-medium text-text-muted">Startup Overhead</span>
+          <AssessmentBadge assessment={startup.overheadAssessment} metricKey="startup" />
+        </div>
+        <div className="grid grid-cols-2 gap-3 sm:grid-cols-3">
+          <div>
+            <div className="text-xs text-text-muted">Messages Before Work</div>
+            <div className="text-sm font-medium text-text">{startup.messagesBeforeFirstWork}</div>
+          </div>
+          <div>
+            <div className="text-xs text-text-muted">Tokens Before Work</div>
+            <div className="text-sm font-medium text-text">
+              {startup.tokensBeforeFirstWork.toLocaleString()}
+            </div>
+          </div>
+          <div>
+            <div className="text-xs text-text-muted">% of Total</div>
+            <div className="text-sm font-medium text-text">{startup.pctOfTotal}%</div>
+          </div>
+        </div>
+      </div>
+
+      {/* File read redundancy */}
+      <div className="mb-4">
+        <div className="mb-2 flex items-center gap-2">
+          <span className="text-xs font-medium text-text-muted">File Read Redundancy</span>
+          <AssessmentBadge
+            assessment={fileReadRedundancy.redundancyAssessment}
+            metricKey="fileReads"
+          />
+        </div>
+        <div className="grid grid-cols-2 gap-3 sm:grid-cols-3">
+          <div>
+            <div className="text-xs text-text-muted">Total Reads</div>
+            <div className="text-sm font-medium text-text">{fileReadRedundancy.totalReads}</div>
+          </div>
+          <div>
+            <div className="text-xs text-text-muted">Unique Files</div>
+            <div className="text-sm font-medium text-text">{fileReadRedundancy.uniqueFiles}</div>
+          </div>
+          <div>
+            <div className="text-xs text-text-muted">Reads/Unique File</div>
+            <div className="text-sm font-medium text-text">
+              {fileReadRedundancy.readsPerUniqueFile}x
+            </div>
+          </div>
+        </div>
+      </div>
+
+      {/* Test progression */}
+      <div>
+        <div className="mb-2 text-xs font-medium text-text-muted">Test Progression</div>
+        <div className="mb-2 flex items-center gap-2">
+          <AssessmentBadge assessment={testProgression.trajectory} metricKey="testTrajectory" />
+          <span className="text-xs text-text-muted">
+            {testProgression.snapshotCount} snapshot{testProgression.snapshotCount !== 1 ? 's' : ''}
+          </span>
+        </div>
+        {testProgression.firstSnapshot && testProgression.lastSnapshot && (
+          <div className="grid grid-cols-2 gap-3">
+            <div>
+              <div className="text-xs text-text-muted">First Run</div>
+              <div className="text-sm text-text">
+                <span style={{ color: severityColor('good') }}>
+                  {testProgression.firstSnapshot.passed} passed
+                </span>
+                {' / '}
+                <span style={{ color: severityColor('danger') }}>
+                  {testProgression.firstSnapshot.failed} failed
+                </span>
+              </div>
+            </div>
+            <div>
+              <div className="text-xs text-text-muted">Last Run</div>
+              <div className="text-sm text-text">
+                <span style={{ color: severityColor('good') }}>
+                  {testProgression.lastSnapshot.passed} passed
+                </span>
+                {' / '}
+                <span style={{ color: severityColor('danger') }}>
+                  {testProgression.lastSnapshot.failed} failed
+                </span>
+              </div>
+            </div>
+          </div>
+        )}
+      </div>
+    </ReportSection>
+  );
+};

src/renderer/components/report/sections/SubagentSection.tsx

@@ -0,0 +1,88 @@
+import { severityColor } from '@renderer/utils/reportAssessments';
+import { Users } from 'lucide-react';
+
+import { ReportSection } from '../ReportSection';
+
+import type { ReportSubagentMetrics } from '@renderer/types/sessionReport';
+
+const fmtCost = (v: number) => `$${v.toFixed(4)}`;
+const fmtDuration = (ms: number) => {
+  const s = Math.round(ms / 1000);
+  const m = Math.floor(s / 60);
+  const sec = s % 60;
+  return m > 0 ? `${m}m ${sec}s` : `${sec}s`;
+};
+
+interface SubagentSectionProps {
+  data: ReportSubagentMetrics;
+  defaultCollapsed?: boolean;
+}
+
+export const SubagentSection = ({ data, defaultCollapsed }: SubagentSectionProps) => {
+  return (
+    <ReportSection title="Subagents" icon={Users} defaultCollapsed={defaultCollapsed}>
+      <div className="mb-4 grid grid-cols-2 gap-3 sm:grid-cols-4">
+        <div>
+          <div className="text-xs text-text-muted">Count</div>
+          <div className="text-sm font-medium text-text">{data.count}</div>
+        </div>
+        <div>
+          <div className="text-xs text-text-muted">Total Tokens</div>
+          <div className="text-sm font-medium text-text">{data.totalTokens.toLocaleString()}</div>
+        </div>
+        <div>
+          <div className="text-xs text-text-muted">Total Duration</div>
+          <div className="text-sm font-medium text-text">{fmtDuration(data.totalDurationMs)}</div>
+        </div>
+        <div>
+          <div className="text-xs text-text-muted">Total Cost</div>
+          <div className="text-sm font-medium text-text">{fmtCost(data.totalCostUsd)}</div>
+        </div>
+      </div>
+
+      {data.byAgent.length > 0 && (
+        <div className="overflow-x-auto">
+          <table className="w-full text-xs">
+            <thead>
+              <tr className="border-b border-border text-left text-text-muted">
+                <th className="pb-2 pr-4">Description</th>
+                <th className="pb-2 pr-4">Type</th>
+                <th className="pb-2 pr-4 text-right">Tokens</th>
+                <th className="pb-2 pr-4 text-right">Duration</th>
+                <th className="pb-2 text-right">Cost</th>
+              </tr>
+            </thead>
+            <tbody>
+              {data.byAgent.map((agent, idx) => (
+                <tr key={idx} className="border-border/50 border-b">
+                  <td className="max-w-48 py-1.5 pr-4 text-text">
+                    <div className="truncate" title={agent.description}>
+                      {agent.description}
+                    </div>
+                    {agent.modelMismatch && (
+                      <div
+                        className="mt-0.5 truncate text-[10px]"
+                        style={{ color: severityColor('warning') }}
+                        title={agent.modelMismatch.recommendation}
+                      >
+                        {agent.modelMismatch.recommendation}
+                      </div>
+                    )}
+                  </td>
+                  <td className="py-1.5 pr-4 text-text-secondary">{agent.subagentType}</td>
+                  <td className="py-1.5 pr-4 text-right text-text">
+                    {agent.totalTokens.toLocaleString()}
+                  </td>
+                  <td className="py-1.5 pr-4 text-right text-text">
+                    {fmtDuration(agent.totalDurationMs)}
+                  </td>
+                  <td className="py-1.5 text-right text-text">{fmtCost(agent.costUsd)}</td>
+                </tr>
+              ))}
+            </tbody>
+          </table>
+        </div>
+      )}
+    </ReportSection>
+  );
+};

src/renderer/components/report/sections/TimelineSection.tsx

@@ -0,0 +1,111 @@
+import { assessmentColor, assessmentLabel } from '@renderer/utils/reportAssessments';
+import { Clock } from 'lucide-react';
+
+import { AssessmentBadge } from '../AssessmentBadge';
+import { ReportSection } from '../ReportSection';
+
+import type {
+  KeyEvent,
+  ReportIdleAnalysis,
+  ReportModelSwitches,
+} from '@renderer/types/sessionReport';
+
+interface TimelineSectionProps {
+  idle: ReportIdleAnalysis;
+  modelSwitches: ReportModelSwitches;
+  keyEvents: KeyEvent[];
+  defaultCollapsed?: boolean;
+}
+
+export const TimelineSection = ({
+  idle,
+  modelSwitches,
+  keyEvents,
+  defaultCollapsed,
+}: TimelineSectionProps) => {
+  const idleColor = assessmentColor(idle.idleAssessment);
+
+  return (
+    <ReportSection title="Timeline & Activity" icon={Clock} defaultCollapsed={defaultCollapsed}>
+      {/* Idle stats */}
+      <div className="mb-4">
+        <div className="mb-2 flex items-center gap-2">
+          <span className="text-xs font-medium text-text-muted">Idle Analysis</span>
+          <AssessmentBadge assessment={idle.idleAssessment} metricKey="idle" />
+        </div>
+        <div className="grid grid-cols-2 gap-3 sm:grid-cols-4">
+          <div>
+            <div className="text-xs text-text-muted">Idle Gaps</div>
+            <div className="text-sm font-medium text-text">{idle.idleGapCount}</div>
+          </div>
+          <div>
+            <div className="text-xs text-text-muted">Total Idle</div>
+            <div className="text-sm font-medium text-text">{idle.totalIdleHuman}</div>
+          </div>
+          <div>
+            <div className="text-xs text-text-muted">Active Time</div>
+            <div className="text-sm font-medium text-text">{idle.activeWorkingHuman}</div>
+          </div>
+          <div>
+            <div className="text-xs text-text-muted">Idle %</div>
+            <div className="text-sm font-medium" style={{ color: idleColor }}>
+              {idle.idlePct}%
+            </div>
+          </div>
+        </div>
+      </div>
+
+      {/* Model switches */}
+      {modelSwitches.count > 0 && (
+        <div className="mb-4">
+          <div className="mb-2 flex items-center gap-2">
+            <span className="text-xs font-medium text-text-muted">
+              Model Switches ({modelSwitches.count})
+            </span>
+            {modelSwitches.switchPattern && (
+              <span
+                className="rounded px-2 py-0.5 text-xs font-medium"
+                style={{
+                  backgroundColor: `${assessmentColor(modelSwitches.switchPattern)}20`,
+                  color: assessmentColor(modelSwitches.switchPattern),
+                }}
+              >
+                {assessmentLabel(modelSwitches.switchPattern)}
+              </span>
+            )}
+          </div>
+          <div className="flex flex-col gap-1">
+            {modelSwitches.switches.map((sw, idx) => (
+              <div key={idx} className="flex items-center gap-2 px-2 py-0.5 text-xs">
+                <span className="text-text-secondary">{sw.from}</span>
+                <span className="text-text-muted">&rarr;</span>
+                <span className="text-text">{sw.to}</span>
+                <span className="ml-auto text-text-muted">msg #{sw.messageIndex}</span>
+              </div>
+            ))}
+          </div>
+        </div>
+      )}
+
+      {/* Key events */}
+      {keyEvents.length > 0 && (
+        <div>
+          <div className="mb-2 text-xs font-medium text-text-muted">Key Events</div>
+          <div className="flex flex-col gap-1">
+            {keyEvents.map((event, idx) => (
+              <div key={idx} className="flex items-center gap-2 px-2 py-0.5 text-xs">
+                <span className="shrink-0 text-text-muted">
+                  {event.timestamp.toLocaleTimeString()}
+                </span>
+                <span className="truncate text-text">{event.label}</span>
+                {event.deltaHuman && (
+                  <span className="ml-auto shrink-0 text-text-muted">+{event.deltaHuman}</span>
+                )}
+              </div>
+            ))}
+          </div>
+        </div>
+      )}
+    </ReportSection>
+  );
+};

src/renderer/components/report/sections/TokenSection.tsx

@@ -0,0 +1,116 @@
+import { Coins } from 'lucide-react';
+
+import { AssessmentBadge } from '../AssessmentBadge';
+import { ReportSection } from '../ReportSection';
+
+import type { ReportCacheEconomics, ReportTokenUsage } from '@renderer/types/sessionReport';
+
+const fmt = (v: number) => v.toLocaleString();
+const fmtCost = (v: number) => `$${v.toFixed(4)}`;
+
+interface TokenSectionProps {
+  data: ReportTokenUsage;
+  cacheEconomics: ReportCacheEconomics;
+  defaultCollapsed?: boolean;
+}
+
+export const TokenSection = ({ data, cacheEconomics, defaultCollapsed }: TokenSectionProps) => {
+  const modelEntries = Object.entries(data.byModel).sort((a, b) => b[1].costUsd - a[1].costUsd);
+
+  return (
+    <ReportSection title="Token Usage" icon={Coins} defaultCollapsed={defaultCollapsed}>
+      {/* By-model table */}
+      <div className="mb-4 overflow-x-auto">
+        <table className="w-full text-xs">
+          <thead>
+            <tr className="border-b border-border text-left text-text-muted">
+              <th className="pb-2 pr-4">Model</th>
+              <th className="pb-2 pr-4 text-right">API Calls</th>
+              <th className="pb-2 pr-4 text-right">Input</th>
+              <th className="pb-2 pr-4 text-right">Output</th>
+              <th className="pb-2 pr-4 text-right">Cache Read</th>
+              <th className="pb-2 pr-4 text-right">Cache Create</th>
+              <th className="pb-2 text-right">Cost</th>
+            </tr>
+          </thead>
+          <tbody>
+            {modelEntries.map(([model, stats]) => (
+              <tr key={model} className="border-border/50 border-b">
+                <td className="py-1.5 pr-4 text-text">{model}</td>
+                <td className="py-1.5 pr-4 text-right text-text">{fmt(stats.apiCalls)}</td>
+                <td className="py-1.5 pr-4 text-right text-text">{fmt(stats.inputTokens)}</td>
+                <td className="py-1.5 pr-4 text-right text-text">{fmt(stats.outputTokens)}</td>
+                <td className="py-1.5 pr-4 text-right text-text">{fmt(stats.cacheRead)}</td>
+                <td className="py-1.5 pr-4 text-right text-text">{fmt(stats.cacheCreation)}</td>
+                <td className="py-1.5 text-right text-text">{fmtCost(stats.costUsd)}</td>
+              </tr>
+            ))}
+            {/* Totals row */}
+            <tr className="border-t border-border font-medium">
+              <td className="py-1.5 pr-4 text-text">Total</td>
+              <td className="py-1.5 pr-4 text-right text-text">
+                {fmt(modelEntries.reduce((s, [, st]) => s + st.apiCalls, 0))}
+              </td>
+              <td className="py-1.5 pr-4 text-right text-text">{fmt(data.totals.inputTokens)}</td>
+              <td className="py-1.5 pr-4 text-right text-text">{fmt(data.totals.outputTokens)}</td>
+              <td className="py-1.5 pr-4 text-right text-text">{fmt(data.totals.cacheRead)}</td>
+              <td className="py-1.5 pr-4 text-right text-text">{fmt(data.totals.cacheCreation)}</td>
+              <td className="py-1.5 text-right text-text">
+                {fmtCost(modelEntries.reduce((s, [, st]) => s + st.costUsd, 0))}
+              </td>
+            </tr>
+          </tbody>
+        </table>
+      </div>
+
+      {/* Cache economics */}
+      <div className="grid grid-cols-2 gap-3 sm:grid-cols-4">
+        <div>
+          <div className="text-xs text-text-muted">Cache Efficiency</div>
+          <div className="flex items-center gap-2">
+            <span className="text-sm font-medium text-text">
+              {cacheEconomics.cacheEfficiencyPct}%
+            </span>
+            {cacheEconomics.cacheEfficiencyAssessment && (
+              <AssessmentBadge
+                assessment={cacheEconomics.cacheEfficiencyAssessment}
+                metricKey="cacheEfficiency"
+              />
+            )}
+          </div>
+        </div>
+        <div>
+          <div className="text-xs text-text-muted">R/W Ratio</div>
+          <div className="flex items-center gap-2">
+            <span className="text-sm font-medium text-text">
+              {cacheEconomics.cacheReadToWriteRatio}x
+            </span>
+            {cacheEconomics.cacheRatioAssessment && (
+              <AssessmentBadge
+                assessment={cacheEconomics.cacheRatioAssessment}
+                metricKey="cacheRatio"
+              />
+            )}
+          </div>
+        </div>
+        <div>
+          <div className="text-xs text-text-muted">Cache Read %</div>
+          <div className="text-sm font-medium text-text">{data.totals.cacheReadPct}%</div>
+        </div>
+        <div>
+          <div className="text-xs text-text-muted">Cold Start</div>
+          <div
+            className="text-sm font-medium"
+            style={{
+              color: cacheEconomics.coldStartDetected
+                ? 'var(--assess-warning)'
+                : 'var(--assess-good)',
+            }}
+          >
+            {cacheEconomics.coldStartDetected ? 'Yes' : 'No'}
+          </div>
+        </div>
+      </div>
+    </ReportSection>
+  );
+};

src/renderer/components/report/sections/ToolSection.tsx

@@ -0,0 +1,77 @@
+import { assessmentColor } from '@renderer/utils/reportAssessments';
+import { Wrench } from 'lucide-react';
+
+import { AssessmentBadge } from '../AssessmentBadge';
+import { ReportSection, sectionId } from '../ReportSection';
+
+import type { ReportToolUsage } from '@renderer/types/sessionReport';
+
+interface ToolSectionProps {
+  data: ReportToolUsage;
+  defaultCollapsed?: boolean;
+}
+
+export const ToolSection = ({ data, defaultCollapsed }: ToolSectionProps) => {
+  const toolEntries = Object.entries(data.successRates).sort(
+    (a, b) => b[1].totalCalls - a[1].totalCalls
+  );
+
+  return (
+    <ReportSection title="Tool Usage" icon={Wrench} defaultCollapsed={defaultCollapsed}>
+      <div className="mb-2 flex items-center gap-2">
+        <span className="text-xs text-text-muted">
+          {data.totalCalls.toLocaleString()} total calls across {toolEntries.length} tools
+        </span>
+        <AssessmentBadge assessment={data.overallToolHealth} metricKey="toolHealth" />
+      </div>
+      <div className="overflow-x-auto">
+        <table className="w-full text-xs">
+          <thead>
+            <tr className="border-b border-border text-left text-text-muted">
+              <th className="pb-2 pr-4">Tool</th>
+              <th className="pb-2 pr-4 text-right">Calls</th>
+              <th className="pb-2 pr-4 text-right">Errors</th>
+              <th className="pb-2 pr-4 text-right">Success %</th>
+              <th className="pb-2 text-right">Health</th>
+            </tr>
+          </thead>
+          <tbody>
+            {toolEntries.map(([tool, stats]) => {
+              const color = assessmentColor(stats.assessment);
+              return (
+                <tr key={tool} className="border-border/50 border-b">
+                  <td className="py-1.5 pr-4 text-text">{tool}</td>
+                  <td className="py-1.5 pr-4 text-right text-text">
+                    {stats.totalCalls.toLocaleString()}
+                  </td>
+                  <td className="py-1.5 pr-4 text-right text-text">
+                    {stats.errors > 0 ? (
+                      <button
+                        type="button"
+                        onClick={() => {
+                          const el = document.getElementById(sectionId('Errors'));
+                          if (el) el.dispatchEvent(new CustomEvent('report-section-expand'));
+                        }}
+                        className="text-red-400 underline decoration-red-400/30 underline-offset-2 hover:decoration-red-400"
+                      >
+                        {stats.errors.toLocaleString()}
+                      </button>
+                    ) : (
+                      stats.errors.toLocaleString()
+                    )}
+                  </td>
+                  <td className="py-1.5 pr-4 text-right" style={{ color }}>
+                    {stats.successRatePct}%
+                  </td>
+                  <td className="py-1.5 text-right">
+                    <AssessmentBadge assessment={stats.assessment} metricKey="toolHealth" />
+                  </td>
+                </tr>
+              );
+            })}
+          </tbody>
+        </table>
+      </div>
+    </ReportSection>
+  );
+};

src/renderer/components/settings/hooks/useSettingsConfig.ts

@@ -31,6 +31,8 @@ export interface SafeConfig {
     defaultTab: 'dashboard' | 'last-session';
     claudeRootPath: string | null;
     agentLanguage: string;
+    autoExpandAIGroups: boolean;
+    useNativeTitleBar: boolean;
   };
   notifications: {
     enabled: boolean;
@@ -156,6 +158,8 @@ export function useSettingsConfig(): UseSettingsConfigReturn {
         defaultTab: displayConfig?.general?.defaultTab ?? 'dashboard',
         claudeRootPath: displayConfig?.general?.claudeRootPath ?? null,
         agentLanguage: displayConfig?.general?.agentLanguage ?? 'system',
+        autoExpandAIGroups: displayConfig?.general?.autoExpandAIGroups ?? false,
+        useNativeTitleBar: displayConfig?.general?.useNativeTitleBar ?? false,
       },
       notifications: {
         enabled: displayConfig?.notifications?.enabled ?? true,

src/renderer/components/settings/hooks/useSettingsHandlers.ts

@@ -296,6 +296,8 @@ export function useSettingsHandlers({
           defaultTab: 'dashboard',
           claudeRootPath: null,
           agentLanguage: 'system',
+          autoExpandAIGroups: false,
+          useNativeTitleBar: false,
         },
         display: {
           showTimestamps: true,

src/renderer/components/settings/sections/GeneralSection.tsx

@@ -17,6 +17,7 @@ import { SettingRow, SettingsSectionHeader, SettingsSelect, SettingsToggle } fro
 import type { SafeConfig } from '../hooks/useSettingsConfig';
 import type { ClaudeRootInfo, WslClaudeRootCandidate } from '@shared/types';
 import type { HttpServerStatus } from '@shared/types/api';
+import type { AppConfig } from '@shared/types/notifications';
 
 // Theme options
 const THEME_OPTIONS = [
@@ -28,7 +29,7 @@ const THEME_OPTIONS = [
 interface GeneralSectionProps {
   readonly safeConfig: SafeConfig;
   readonly saving: boolean;
-  readonly onGeneralToggle: (key: 'launchAtLogin' | 'showDockIcon', value: boolean) => void;
+  readonly onGeneralToggle: (key: keyof AppConfig['general'], value: boolean) => void;
   readonly onThemeChange: (value: 'dark' | 'light' | 'system') => void;
   readonly onLanguageChange: (value: string) => void;
 }
@@ -341,6 +342,41 @@ export const GeneralSection = ({
           disabled={saving}
         />
       </SettingRow>
+      <SettingRow
+        label="Expand AI responses by default"
+        description="Automatically expand each response turn when opening a transcript or receiving a new message"
+      >
+        <SettingsToggle
+          enabled={safeConfig.general.autoExpandAIGroups ?? false}
+          onChange={(v) => onGeneralToggle('autoExpandAIGroups', v)}
+          disabled={saving}
+        />
+      </SettingRow>
+      {isElectron && !window.navigator.userAgent.includes('Macintosh') && (
+        <SettingRow
+          label="Use native title bar"
+          description="Use the default system window frame instead of the custom title bar"
+        >
+          <SettingsToggle
+            enabled={safeConfig.general.useNativeTitleBar}
+            onChange={async (v) => {
+              const shouldRelaunch = await confirm({
+                title: 'Restart required',
+                message: 'The app needs to restart to apply the title bar change. Restart now?',
+                confirmLabel: 'Restart',
+              });
+              if (shouldRelaunch) {
+                onGeneralToggle('useNativeTitleBar', v);
+                // Small delay to let config persist before relaunch
+                setTimeout(() => {
+                  void window.electronAPI?.windowControls?.relaunch();
+                }, 200);
+              }
+            }}
+            disabled={saving}
+          />
+        </SettingRow>
+      )}
 
       {isElectron && (
         <>

src/renderer/components/sidebar/SessionContextMenu.tsx

@@ -7,6 +7,7 @@
 import { useEffect, useRef, useState } from 'react';
 
 import { MAX_PANES } from '@renderer/types/panes';
+import { formatShortcut } from '@renderer/utils/stringUtils';
 import { Check, ClipboardCopy, Eye, EyeOff, Pin, PinOff, Terminal } from 'lucide-react';
 
 interface SessionContextMenuProps {
@@ -98,7 +99,11 @@ export const SessionContextMenu = ({
       }}
     >
       <MenuItem label="Open in Current Pane" onClick={handleClick(onOpenInCurrentPane)} />
-      <MenuItem label="Open in New Tab" shortcut="⌘ Click" onClick={handleClick(onOpenInNewTab)} />
+      <MenuItem
+        label="Open in New Tab"
+        shortcut={`${formatShortcut('')}Click`}
+        onClick={handleClick(onOpenInNewTab)}
+      />
       <div className="mx-2 my-1 border-t" style={{ borderColor: 'var(--color-border)' }} />
       <MenuItem
         label="Split Right and Open"

src/renderer/hooks/useAutoScrollBottom.ts

@@ -138,6 +138,8 @@ export function useAutoScrollBottom(
   const disabledRef = useRef(disabled);
   // Track resetKey to detect changes
   const prevResetKeyRef = useRef(resetKey);
+  // Set true when resetKey changes; consumed by the content effect to force scroll on first load
+  const needsInitialScrollRef = useRef(false);
 
   /**
    * Check if the scroll container is at the bottom.
@@ -223,34 +225,47 @@ export function useAutoScrollBottom(
     disabledRef.current = disabled;
   }, [disabled]);
 
-  // Reset isAtBottom state when resetKey changes (e.g., tab/session switch)
-  // This ensures new content will auto-scroll to bottom
+  // Reset isAtBottom state when resetKey changes (e.g., tab/session switch).
+  // Sets needsInitialScrollRef so the content effect scrolls to bottom on first load.
   useEffect(() => {
     if (resetKey !== prevResetKeyRef.current) {
       isAtBottomRef.current = true;
       wasAtBottomBeforeUpdateRef.current = true;
       prevResetKeyRef.current = resetKey;
+      needsInitialScrollRef.current = true;
     }
   }, [resetKey]);
 
   /**
-   * After content updates (dependencies change), scroll to bottom if we were at bottom.
+   * After content updates (dependencies change), scroll to bottom if:
+   * - User was already near the bottom before the update, OR
+   * - This is the first load after a tab/session switch (needsInitialScrollRef)
+   * Uses double-RAF + cleanup so React StrictMode's double-invoke doesn't fire twice.
    */
   useEffect(() => {
     // Skip if disabled (e.g., during navigation) or not enabled
     if (!enabled || disabled) return;
 
-    // Use requestAnimationFrame to ensure DOM has updated
-    requestAnimationFrame(() => {
-      // Re-check disabled state inside RAF - it might have changed between effect and callback
-      // This prevents auto-scroll from firing if navigation started after the effect ran
-      if (disabledRef.current) return;
+    let id1 = 0;
+    let id2 = 0;
 
-      // Only auto-scroll if user was at bottom before the update
-      if (wasAtBottomBeforeUpdateRef.current) {
-        scrollToBottom(autoBehavior);
-      }
+    id1 = requestAnimationFrame(() => {
+      id2 = requestAnimationFrame(() => {
+        // Re-check disabled state — navigation may have started between effect and RAF
+        if (disabledRef.current) return;
+
+        const shouldScroll = needsInitialScrollRef.current || wasAtBottomBeforeUpdateRef.current;
+        if (shouldScroll) {
+          needsInitialScrollRef.current = false;
+          scrollToBottom(autoBehavior);
+        }
+      });
     });
+
+    return () => {
+      cancelAnimationFrame(id1);
+      cancelAnimationFrame(id2);
+    };
     // eslint-disable-next-line react-hooks/exhaustive-deps -- Dynamic dependencies array is intentional design
   }, [...dependencies, enabled, disabled, autoBehavior, scrollToBottom]);
 

src/renderer/index.css

@@ -181,6 +181,12 @@
   --card-text-lighter: #e2e8f0;
   --card-separator: #2a2c38;
 
+  /* Assessment severity colors (badges, health indicators) */
+  --assess-good: #4ade80;
+  --assess-warning: #fbbf24;
+  --assess-danger: #f87171;
+  --assess-neutral: #a1a1aa;
+
   /* Sticky Context button — indigo glass */
   --context-btn-bg: rgba(148, 163, 184, 0.08);
   --context-btn-bg-hover: rgba(148, 163, 184, 0.14);
@@ -206,6 +212,12 @@
   --color-text-secondary: #4d4b46; /* Warm secondary text */
   --color-text-muted: #6d6b65; /* Warm muted text */
 
+  /* Assessment severity colors - darker for light backgrounds */
+  --assess-good: #16a34a;
+  --assess-warning: #d97706;
+  --assess-danger: #dc2626;
+  --assess-neutral: #57534e;
+
   /* Scrollbar colors for light mode */
   --scrollbar-thumb: rgba(0, 0, 0, 0.15);
   --scrollbar-thumb-hover: rgba(0, 0, 0, 0.28);

src/renderer/store/slices/sessionDetailSlice.ts

@@ -416,6 +416,15 @@ export const createSessionDetailSlice: StateCreator<AppState, [], [], SessionDet
         sessionPhaseInfo: phaseInfo,
       });
 
+      // Auto-expand all AI groups if the setting is enabled
+      if (tabId && conversation?.items && get().appConfig?.general?.autoExpandAIGroups) {
+        for (const item of conversation.items) {
+          if (item.type === 'ai') {
+            get().expandAIGroupForTab(tabId, item.group.id);
+          }
+        }
+      }
+
       // Store per-tab session data
       if (tabId) {
         const prev = get().tabSessionData;
@@ -554,6 +563,14 @@ export const createSessionDetailSlice: StateCreator<AppState, [], [], SessionDet
         }
       }
 
+      // Snapshot existing AI group IDs before overwriting state, so the
+      // auto-expand diff below can correctly identify which groups are new.
+      const prevGroupIds = new Set(
+        (latestState.conversation?.items ?? [])
+          .filter((item) => item.type === 'ai')
+          .map((item) => (item as { type: 'ai'; group: { id: string } }).group.id)
+      );
+
       // Update only the data, preserve UI states
       set((state) => ({
         sessionDetail: detail,
@@ -572,6 +589,29 @@ export const createSessionDetailSlice: StateCreator<AppState, [], [], SessionDet
         // so expansion states are preserved
       }));
 
+      // Auto-expand newly arrived AI groups if the setting is enabled.
+      // Uses prevGroupIds snapshotted before set() so the diff is accurate.
+      if (get().appConfig?.general?.autoExpandAIGroups) {
+        const oldGroupIds = prevGroupIds;
+        const newGroupIds = newConversation.items
+          .filter(
+            (item) =>
+              item.type === 'ai' &&
+              !oldGroupIds.has((item as { type: 'ai'; group: { id: string } }).group.id)
+          )
+          .map((item) => (item as { type: 'ai'; group: { id: string } }).group.id);
+
+        if (newGroupIds.length > 0) {
+          for (const tab of latestAllTabs) {
+            if (tab.type === 'session' && tab.sessionId === sessionId) {
+              for (const groupId of newGroupIds) {
+                get().expandAIGroupForTab(tab.id, groupId);
+              }
+            }
+          }
+        }
+      }
+
       // Also update per-tab session data for all tabs viewing this session
       const latestTabSessionData = { ...get().tabSessionData };
       for (const tab of latestAllTabs) {

src/renderer/store/slices/tabSlice.ts

@@ -51,6 +51,7 @@ export interface TabSlice {
   closeTab: (tabId: string) => void;
   setActiveTab: (tabId: string) => void;
   openDashboard: () => void;
+  openSessionReport: (sourceTabId: string) => void;
   getActiveTab: () => Tab | null;
   isSessionOpen: (sessionId: string) => boolean;
   enqueueTabNavigation: (tabId: string, request: TabNavigationRequest) => void;
@@ -423,6 +424,28 @@ export const createTabSlice: StateCreator<AppState, [], [], TabSlice> = (set, ge
     set(syncFromLayout(newLayout));
   },
 
+  // Open a session report tab based on a source session tab
+  openSessionReport: (sourceTabId: string) => {
+    const state = get();
+    const allTabs = getAllTabs(state.paneLayout);
+    const sourceTab = allTabs.find((t) => t.id === sourceTabId);
+    if (sourceTab?.type !== 'session') return;
+    if (!sourceTab.sessionId || !sourceTab.projectId) return;
+
+    const tabData = state.tabSessionData[sourceTabId];
+    const firstMsg = tabData?.sessionDetail?.session.firstMessage;
+    const label = firstMsg
+      ? `Report: ${firstMsg.slice(0, 30)}${firstMsg.length > 30 ? '…' : ''}`
+      : 'Session Report';
+
+    state.openTab({
+      type: 'report',
+      label,
+      projectId: sourceTab.projectId,
+      sessionId: sourceTab.sessionId,
+    });
+  },
+
   // Get the currently active tab (from the focused pane)
   getActiveTab: () => {
     const state = get();

src/renderer/types/sessionReport.ts

@@ -0,0 +1,386 @@
+/**
+ * Session analysis report types.
+ * Output of analyzeSession() — one interface per report section.
+ */
+
+import type {
+  CacheAssessment,
+  CostAssessment,
+  IdleAssessment,
+  ModelMismatch,
+  OverheadAssessment,
+  RedundancyAssessment,
+  SubagentCostShareAssessment,
+  SwitchPattern,
+  ThrashingAssessment,
+  ToolHealthAssessment,
+} from '@renderer/utils/reportAssessments';
+
+// =============================================================================
+// Pricing
+// =============================================================================
+
+export type { DisplayPricing as ModelPricing } from '@shared/utils/pricing';
+
+// =============================================================================
+// Report Sections
+// =============================================================================
+
+export interface ReportOverview {
+  sessionId: string;
+  projectId: string;
+  projectPath: string;
+  firstMessage: string;
+  messageCount: number;
+  hasSubagents: boolean;
+  contextConsumption: number;
+  contextConsumptionPct: number | null;
+  contextAssessment: 'critical' | 'high' | 'moderate' | 'healthy' | null;
+  compactionCount: number;
+  gitBranch: string;
+  startTime: Date | null;
+  endTime: Date | null;
+  durationSeconds: number;
+  durationHuman: string;
+  totalMessages: number;
+}
+
+export interface ModelTokenStats {
+  apiCalls: number;
+  inputTokens: number;
+  outputTokens: number;
+  cacheCreation: number;
+  cacheRead: number;
+  costUsd: number;
+}
+
+export interface TokenTotals {
+  inputTokens: number;
+  outputTokens: number;
+  cacheCreation: number;
+  cacheRead: number;
+  grandTotal: number;
+  cacheReadPct: number;
+}
+
+export interface ReportTokenUsage {
+  byModel: Record<string, ModelTokenStats>;
+  totals: TokenTotals;
+}
+
+export interface ReportCostAnalysis {
+  parentCostUsd: number;
+  subagentCostUsd: number;
+  totalSessionCostUsd: number;
+  costByModel: Record<string, number>;
+  costPerCommit: number | null;
+  costPerLineChanged: number | null;
+  costPerCommitAssessment: CostAssessment | null;
+  costPerLineAssessment: CostAssessment | null;
+  subagentCostSharePct: number | null;
+  subagentCostShareAssessment: SubagentCostShareAssessment | null;
+}
+
+export interface ReportCacheEconomics {
+  cacheRead: number;
+  cacheEfficiencyPct: number;
+  coldStartDetected: boolean;
+  cacheReadToWriteRatio: number;
+  cacheEfficiencyAssessment: CacheAssessment | null;
+  cacheRatioAssessment: CacheAssessment | null;
+}
+
+export interface ToolSuccessRate {
+  totalCalls: number;
+  errors: number;
+  successRatePct: number;
+  assessment: ToolHealthAssessment;
+}
+
+export interface ReportToolUsage {
+  counts: Record<string, number>;
+  totalCalls: number;
+  successRates: Record<string, ToolSuccessRate>;
+  overallToolHealth: ToolHealthAssessment;
+}
+
+export interface SubagentEntry {
+  description: string;
+  subagentType: string;
+  model: string;
+  totalTokens: number;
+  totalDurationMs: number;
+  totalToolUseCount: number;
+  costUsd: number;
+  costNote?: string;
+  modelMismatch: ModelMismatch | null;
+}
+
+export interface ReportSubagentMetrics {
+  count: number;
+  totalTokens: number;
+  totalDurationMs: number;
+  totalToolUseCount: number;
+  totalCostUsd: number;
+  byAgent: SubagentEntry[];
+}
+
+export interface ToolError {
+  tool: string;
+  inputPreview: string;
+  error: string;
+  messageIndex: number;
+  isPermissionDenial: boolean;
+}
+
+export interface ReportErrors {
+  errors: ToolError[];
+  permissionDenials: {
+    count: number;
+    denials: ToolError[];
+    affectedTools: string[];
+  };
+}
+
+export interface GitCommit {
+  messagePreview: string;
+  messageIndex: number;
+}
+
+export interface ReportGitActivity {
+  commitCount: number;
+  commits: GitCommit[];
+  pushCount: number;
+  branchCreations: string[];
+  linesAdded: number;
+  linesRemoved: number;
+  linesChanged: number;
+}
+
+export interface FrictionCorrection {
+  messageIndex: number;
+  keyword: string;
+  preview: string;
+}
+
+export interface ReportFrictionSignals {
+  correctionCount: number;
+  corrections: FrictionCorrection[];
+  frictionRate: number;
+}
+
+export interface ReportThrashingSignals {
+  bashNearDuplicates: { prefix: string; count: number }[];
+  editReworkFiles: { filePath: string; editIndices: number[] }[];
+  thrashingAssessment: ThrashingAssessment;
+}
+
+export interface ReportConversationTree {
+  totalNodes: number;
+  maxDepth: number;
+  sidechainCount: number;
+  branchPoints: number;
+  branchDetails: {
+    parentUuid: string;
+    childCount: number;
+    parentMessageIndex: number | undefined;
+  }[];
+}
+
+export interface IdleGap {
+  gapSeconds: number;
+  gapHuman: string;
+  afterMessageIndex: number;
+}
+
+export interface ReportIdleAnalysis {
+  idleThresholdSeconds: number;
+  idleGapCount: number;
+  totalIdleSeconds: number;
+  totalIdleHuman: string;
+  wallClockSeconds: number;
+  activeWorkingSeconds: number;
+  activeWorkingHuman: string;
+  idlePct: number;
+  longestGaps: IdleGap[];
+  idleAssessment: IdleAssessment;
+}
+
+export interface ModelSwitch {
+  from: string;
+  to: string;
+  messageIndex: number;
+  timestamp: Date | null;
+}
+
+export interface ReportModelSwitches {
+  count: number;
+  switches: ModelSwitch[];
+  modelsUsed: string[];
+  switchPattern: SwitchPattern | null;
+}
+
+export interface ReportWorkingDirectories {
+  uniqueDirectories: string[];
+  directoryCount: number;
+  changes: { from: string; to: string; messageIndex: number }[];
+  changeCount: number;
+  isMultiDirectory: boolean;
+}
+
+export interface TestSnapshot {
+  messageIndex: number;
+  passed: number;
+  failed: number;
+  total: number;
+  raw: string;
+}
+
+export interface ReportTestProgression {
+  snapshotCount: number;
+  snapshots: TestSnapshot[];
+  trajectory: 'improving' | 'regressing' | 'stable' | 'insufficient_data';
+  firstSnapshot: TestSnapshot | null;
+  lastSnapshot: TestSnapshot | null;
+}
+
+export interface ReportStartupOverhead {
+  messagesBeforeFirstWork: number;
+  tokensBeforeFirstWork: number;
+  pctOfTotal: number;
+  overheadAssessment: OverheadAssessment;
+}
+
+export interface ReportTokenDensityTimeline {
+  quartiles: { q: number; avgTokens: number; messageCount: number }[];
+}
+
+export interface ReportPromptQuality {
+  firstMessageLengthChars: number;
+  userMessageCount: number;
+  correctionCount: number;
+  frictionRate: number;
+  assessment: 'underspecified' | 'verbose_but_unclear' | 'well_specified' | 'moderate_friction';
+  note: string;
+}
+
+export interface ThinkingBlockAnalysis {
+  messageIndex: number;
+  preview: string;
+  charLength: number;
+  signals: Record<string, boolean>;
+}
+
+export interface ReportThinkingBlocks {
+  count: number;
+  analyzedCount: number;
+  signalSummary: Record<string, number>;
+  notableBlocks: ThinkingBlockAnalysis[];
+}
+
+export interface KeyEvent {
+  timestamp: Date;
+  label: string;
+  deltaSeconds?: number;
+  deltaHuman?: string;
+}
+
+export interface ReportFileReadRedundancy {
+  totalReads: number;
+  uniqueFiles: number;
+  readsPerUniqueFile: number;
+  redundantFiles: Record<string, number>;
+  redundancyAssessment: RedundancyAssessment;
+}
+
+// =============================================================================
+// Missing Sections (ported from Python analyzer)
+// =============================================================================
+
+export interface SkillInvocation {
+  skill: string;
+  argsPreview: string;
+}
+
+export interface ReportBashCommands {
+  total: number;
+  unique: number;
+  repeated: Record<string, number>;
+}
+
+export interface UserQuestion {
+  question: string;
+  options: string[];
+}
+
+export interface OutOfScopeFindings {
+  keyword: string;
+  messageIndex: number;
+  snippet: string;
+}
+
+export interface AgentTreeNode {
+  agentId: string;
+  agentType: string;
+  teamName: string;
+  parentToolUseId: string;
+  messageIndex: number;
+}
+
+export interface ReportAgentTree {
+  agentCount: number;
+  agents: AgentTreeNode[];
+  hasTeamMode: boolean;
+  teamNames: string[];
+}
+
+export interface ReportCompaction {
+  count: number;
+  compactSummaryCount: number;
+  note: string;
+}
+
+export interface SubagentBasicEntry {
+  description: string;
+  subagentType: string;
+  model: string;
+  runInBackground: boolean;
+}
+
+// =============================================================================
+// Combined Report
+// =============================================================================
+
+export interface SessionReport {
+  overview: ReportOverview;
+  tokenUsage: ReportTokenUsage;
+  costAnalysis: ReportCostAnalysis;
+  cacheEconomics: ReportCacheEconomics;
+  toolUsage: ReportToolUsage;
+  subagentMetrics: ReportSubagentMetrics;
+  subagentsList: SubagentBasicEntry[];
+  errors: ReportErrors;
+  gitActivity: ReportGitActivity;
+  frictionSignals: ReportFrictionSignals;
+  thrashingSignals: ReportThrashingSignals;
+  conversationTree: ReportConversationTree;
+  idleAnalysis: ReportIdleAnalysis;
+  modelSwitches: ReportModelSwitches;
+  workingDirectories: ReportWorkingDirectories;
+  testProgression: ReportTestProgression;
+  startupOverhead: ReportStartupOverhead;
+  tokenDensityTimeline: ReportTokenDensityTimeline;
+  promptQuality: ReportPromptQuality;
+  thinkingBlocks: ReportThinkingBlocks;
+  keyEvents: KeyEvent[];
+  messageTypes: Record<string, number>;
+  fileReadRedundancy: ReportFileReadRedundancy;
+  compaction: ReportCompaction;
+  gitBranches: string[];
+  skillsInvoked: SkillInvocation[];
+  bashCommands: ReportBashCommands;
+  lifecycleTasks: string[];
+  userQuestions: UserQuestion[];
+  outOfScopeFindings: OutOfScopeFindings[];
+  agentTree: ReportAgentTree;
+}

src/renderer/types/tabs.ts

@@ -76,7 +76,7 @@ export interface Tab {
   id: string;
 
   /** Type of content displayed in this tab */
-  type: 'session' | 'dashboard' | 'notifications' | 'settings' | 'teams' | 'team';
+  type: 'session' | 'dashboard' | 'notifications' | 'settings' | 'teams' | 'team' | 'report';
 
   /** Session ID (required when type === 'session') */
   sessionId?: string;

src/renderer/utils/reportAssessments.ts

@@ -0,0 +1,555 @@
+/**
+ * Centralized assessment severity/color utilities for session reports.
+ *
+ * Maps raw assessment values to severity levels and colors,
+ * replacing duplicated assessmentColor() functions across report sections.
+ */
+
+// =============================================================================
+// Types
+// =============================================================================
+
+export type Severity = 'good' | 'warning' | 'danger' | 'neutral';
+
+// =============================================================================
+// Colors
+// =============================================================================
+
+const SEVERITY_CSS_VAR: Record<Severity, string> = {
+  good: '--assess-good',
+  warning: '--assess-warning',
+  danger: '--assess-danger',
+  neutral: '--assess-neutral',
+};
+
+const SEVERITY_FALLBACKS: Record<Severity, string> = {
+  good: '#4ade80',
+  warning: '#fbbf24',
+  danger: '#f87171',
+  neutral: '#a1a1aa',
+};
+
+export function severityColor(severity: Severity): string {
+  if (typeof document === 'undefined') return SEVERITY_FALLBACKS[severity];
+  const value = getComputedStyle(document.documentElement)
+    .getPropertyValue(SEVERITY_CSS_VAR[severity])
+    .trim();
+  return value || SEVERITY_FALLBACKS[severity];
+}
+
+// =============================================================================
+// Assessment → Severity Mapping
+// =============================================================================
+
+const ASSESSMENT_SEVERITY: Record<string, Severity> = {
+  // Context
+  healthy: 'good',
+  moderate: 'warning',
+  high: 'danger',
+  critical: 'danger',
+
+  // Cost / subagent share
+  efficient: 'good',
+  normal: 'good',
+  expensive: 'warning',
+  red_flag: 'danger',
+  very_high: 'danger',
+
+  // Cache
+  good: 'good',
+  concerning: 'warning',
+
+  // Tool health
+  degraded: 'warning',
+  unreliable: 'danger',
+
+  // Idle ('moderate' already mapped above under Context)
+  high_idle: 'danger',
+
+  // File read
+  wasteful: 'warning',
+
+  // Startup
+  heavy: 'warning',
+
+  // Thrashing
+  none: 'good',
+  mild: 'warning',
+  severe: 'danger',
+
+  // Prompt quality
+  well_specified: 'good',
+  moderate_friction: 'warning',
+  underspecified: 'danger',
+  verbose_but_unclear: 'danger',
+
+  // Test trajectory
+  improving: 'good',
+  stable: 'warning',
+  regressing: 'danger',
+  insufficient_data: 'neutral',
+
+  // Model switch
+  opus_plan_mode: 'good',
+  manual_switch: 'neutral',
+};
+
+export function assessmentSeverity(assessment: string | null | undefined): Severity {
+  if (!assessment) return 'neutral';
+  return ASSESSMENT_SEVERITY[assessment] ?? 'neutral';
+}
+
+export function assessmentColor(assessment: string | null | undefined): string {
+  return severityColor(assessmentSeverity(assessment));
+}
+
+// =============================================================================
+// Label Formatting
+// =============================================================================
+
+export function assessmentLabel(value: string): string {
+  return value
+    .split('_')
+    .map((w) => w.charAt(0).toUpperCase() + w.slice(1))
+    .join(' ');
+}
+
+// =============================================================================
+// Threshold Constants
+// =============================================================================
+
+export const THRESHOLDS = {
+  costPerCommit: {
+    efficient: 0.5,
+    normal: 2,
+    expensive: 5,
+  },
+  costPerLine: {
+    efficient: 0.01,
+    normal: 0.05,
+    expensive: 0.2,
+  },
+  subagentCostShare: {
+    normal: 30,
+    high: 60,
+    veryHigh: 80,
+  },
+  cacheEfficiency: {
+    good: 95,
+  },
+  cacheRwRatio: {
+    good: 20,
+  },
+  toolSuccess: {
+    healthy: 95,
+    degraded: 80,
+  },
+  idle: {
+    efficient: 20,
+    moderate: 50,
+  },
+  fileReadsPerUnique: {
+    normal: 2.0,
+  },
+  startupOverhead: {
+    normal: 5,
+  },
+} as const;
+
+// =============================================================================
+// Metric Keys & Explanations
+// =============================================================================
+
+export type MetricKey =
+  | 'costPerCommit'
+  | 'costPerLine'
+  | 'subagentCostShare'
+  | 'cacheEfficiency'
+  | 'cacheRatio'
+  | 'toolHealth'
+  | 'idle'
+  | 'fileReads'
+  | 'startup'
+  | 'thrashing'
+  | 'promptQuality'
+  | 'testTrajectory';
+
+const EXPLANATIONS: Record<string, Record<string, string>> = {
+  costPerCommit: {
+    efficient: `Under $${THRESHOLDS.costPerCommit.efficient}/commit`,
+    normal: `$${THRESHOLDS.costPerCommit.efficient}\u2013$${THRESHOLDS.costPerCommit.normal}/commit`,
+    expensive: `$${THRESHOLDS.costPerCommit.normal}\u2013$${THRESHOLDS.costPerCommit.expensive}/commit`,
+    red_flag: `Over $${THRESHOLDS.costPerCommit.expensive}/commit`,
+  },
+  costPerLine: {
+    efficient: `Under $${THRESHOLDS.costPerLine.efficient}/line`,
+    normal: `$${THRESHOLDS.costPerLine.efficient}\u2013$${THRESHOLDS.costPerLine.normal}/line`,
+    expensive: `$${THRESHOLDS.costPerLine.normal}\u2013$${THRESHOLDS.costPerLine.expensive}/line`,
+    red_flag: `Over $${THRESHOLDS.costPerLine.expensive}/line`,
+  },
+  subagentCostShare: {
+    normal: `Under ${THRESHOLDS.subagentCostShare.normal}% of total cost`,
+    high: `${THRESHOLDS.subagentCostShare.normal}\u2013${THRESHOLDS.subagentCostShare.high}% of total cost`,
+    very_high: `${THRESHOLDS.subagentCostShare.high}\u2013${THRESHOLDS.subagentCostShare.veryHigh}% of total cost`,
+    red_flag: `Over ${THRESHOLDS.subagentCostShare.veryHigh}% of total cost`,
+  },
+  cacheEfficiency: {
+    good: `${THRESHOLDS.cacheEfficiency.good}%+ cache hit rate`,
+    concerning: `Below ${THRESHOLDS.cacheEfficiency.good}% cache hit rate`,
+  },
+  cacheRatio: {
+    good: `${THRESHOLDS.cacheRwRatio.good}x+ read-to-write ratio`,
+    concerning: `Below ${THRESHOLDS.cacheRwRatio.good}x read-to-write ratio`,
+  },
+  toolHealth: {
+    healthy: `Over ${THRESHOLDS.toolSuccess.healthy}% success rate`,
+    degraded: `${THRESHOLDS.toolSuccess.degraded}\u2013${THRESHOLDS.toolSuccess.healthy}% success rate`,
+    unreliable: `Below ${THRESHOLDS.toolSuccess.degraded}% success rate`,
+  },
+  idle: {
+    efficient: `Under ${THRESHOLDS.idle.efficient}% idle time`,
+    moderate: `${THRESHOLDS.idle.efficient}\u2013${THRESHOLDS.idle.moderate}% idle time`,
+    high_idle: `Over ${THRESHOLDS.idle.moderate}% idle time`,
+  },
+  fileReads: {
+    normal: `${THRESHOLDS.fileReadsPerUnique.normal}x or fewer reads per unique file`,
+    wasteful: `Over ${THRESHOLDS.fileReadsPerUnique.normal}x reads per unique file`,
+  },
+  startup: {
+    normal: `${THRESHOLDS.startupOverhead.normal}% or less of tokens before first work`,
+    heavy: `Over ${THRESHOLDS.startupOverhead.normal}% of tokens before first work`,
+  },
+  thrashing: {
+    none: 'No repeated commands or reworked files',
+    mild: '1\u20132 thrashing signals detected',
+    severe: '3+ thrashing signals detected',
+  },
+  promptQuality: {
+    well_specified: 'Clear first message with low friction rate',
+    moderate_friction: 'Some corrections needed mid-session',
+    underspecified: 'Short initial prompt led to many corrections',
+    verbose_but_unclear: 'Long initial prompt but still high friction',
+  },
+  testTrajectory: {
+    improving: 'Test failures decreased over the session',
+    stable: 'Test results stayed roughly the same',
+    regressing: 'Test failures increased over the session',
+    insufficient_data: 'Not enough test runs to determine trend',
+  },
+};
+
+export function assessmentExplanation(metricKey: MetricKey, assessment: string): string {
+  return EXPLANATIONS[metricKey]?.[assessment] ?? '';
+}
+
+// =============================================================================
+// Assessment Computers
+// =============================================================================
+
+export type CostAssessment = 'efficient' | 'normal' | 'expensive' | 'red_flag';
+export type CacheAssessment = 'good' | 'concerning';
+export type ToolHealthAssessment = 'healthy' | 'degraded' | 'unreliable';
+export type IdleAssessment = 'efficient' | 'moderate' | 'high_idle';
+export type RedundancyAssessment = 'normal' | 'wasteful';
+export type OverheadAssessment = 'normal' | 'heavy';
+export type ThrashingAssessment = 'none' | 'mild' | 'severe';
+export type SubagentCostShareAssessment = 'normal' | 'high' | 'very_high' | 'red_flag';
+export type SwitchPattern = 'opus_plan_mode' | 'manual_switch' | 'none';
+
+export function computeCostPerCommitAssessment(costPerCommit: number): CostAssessment {
+  if (costPerCommit < THRESHOLDS.costPerCommit.efficient) return 'efficient';
+  if (costPerCommit < THRESHOLDS.costPerCommit.normal) return 'normal';
+  if (costPerCommit < THRESHOLDS.costPerCommit.expensive) return 'expensive';
+  return 'red_flag';
+}
+
+export function computeCostPerLineAssessment(costPerLine: number): CostAssessment {
+  if (costPerLine < THRESHOLDS.costPerLine.efficient) return 'efficient';
+  if (costPerLine < THRESHOLDS.costPerLine.normal) return 'normal';
+  if (costPerLine < THRESHOLDS.costPerLine.expensive) return 'expensive';
+  return 'red_flag';
+}
+
+export function computeSubagentCostShareAssessment(pct: number): SubagentCostShareAssessment {
+  if (pct < THRESHOLDS.subagentCostShare.normal) return 'normal';
+  if (pct < THRESHOLDS.subagentCostShare.high) return 'high';
+  if (pct < THRESHOLDS.subagentCostShare.veryHigh) return 'very_high';
+  return 'red_flag';
+}
+
+export function computeCacheEfficiencyAssessment(pct: number): CacheAssessment {
+  return pct >= THRESHOLDS.cacheEfficiency.good ? 'good' : 'concerning';
+}
+
+export function computeCacheRatioAssessment(ratio: number): CacheAssessment {
+  return ratio >= THRESHOLDS.cacheRwRatio.good ? 'good' : 'concerning';
+}
+
+export function computeToolHealthAssessment(successPct: number): ToolHealthAssessment {
+  if (successPct > THRESHOLDS.toolSuccess.healthy) return 'healthy';
+  if (successPct >= THRESHOLDS.toolSuccess.degraded) return 'degraded';
+  return 'unreliable';
+}
+
+export function computeIdleAssessment(idlePct: number): IdleAssessment {
+  if (idlePct < THRESHOLDS.idle.efficient) return 'efficient';
+  if (idlePct < THRESHOLDS.idle.moderate) return 'moderate';
+  return 'high_idle';
+}
+
+export function computeRedundancyAssessment(readsPerUnique: number): RedundancyAssessment {
+  return readsPerUnique <= THRESHOLDS.fileReadsPerUnique.normal ? 'normal' : 'wasteful';
+}
+
+export function computeOverheadAssessment(pctOfTotal: number): OverheadAssessment {
+  return pctOfTotal <= THRESHOLDS.startupOverhead.normal ? 'normal' : 'heavy';
+}
+
+export function computeThrashingAssessment(signalCount: number): ThrashingAssessment {
+  if (signalCount === 0) return 'none';
+  if (signalCount <= 2) return 'mild';
+  return 'severe';
+}
+
+export interface ModelMismatch {
+  description: string;
+  expectedComplexity: 'mechanical' | 'read_only';
+  recommendation: string;
+}
+
+const MECHANICAL_PATTERNS = /\b(rename|move|lint|format|delete|remove|copy|replace)\b/i;
+const READ_ONLY_PATTERNS = /\b(explore|search|find|verify|check|scan|discover|list|read)\b/i;
+
+export function detectModelMismatch(description: string, model: string): ModelMismatch | null {
+  const isOpus = model.toLowerCase().includes('opus');
+  if (!isOpus) return null;
+
+  if (MECHANICAL_PATTERNS.test(description)) {
+    return {
+      description,
+      expectedComplexity: 'mechanical',
+      recommendation: 'Consider using Haiku for mechanical tasks to reduce cost.',
+    };
+  }
+
+  if (READ_ONLY_PATTERNS.test(description)) {
+    return {
+      description,
+      expectedComplexity: 'read_only',
+      recommendation: 'Consider using Haiku or Sonnet for read-only exploration tasks.',
+    };
+  }
+
+  return null;
+}
+
+export function detectSwitchPattern(
+  switches: { from: string; to: string }[]
+): SwitchPattern | null {
+  if (switches.length === 0) return null;
+  if (switches.length < 2) return 'manual_switch';
+
+  // Look for Sonnet→Opus→Sonnet pattern (plan mode)
+  for (let i = 0; i < switches.length - 1; i++) {
+    const s1 = switches[i];
+    const s2 = switches[i + 1];
+    if (
+      s1.from.toLowerCase().includes('sonnet') &&
+      s1.to.toLowerCase().includes('opus') &&
+      s2.from.toLowerCase().includes('opus') &&
+      s2.to.toLowerCase().includes('sonnet')
+    ) {
+      return 'opus_plan_mode';
+    }
+  }
+
+  return 'manual_switch';
+}
+
+// =============================================================================
+// Key Takeaways
+// =============================================================================
+
+export interface Takeaway {
+  severity: Severity;
+  title: string;
+  detail: string;
+  sectionTitle: string;
+}
+
+interface TakeawayReport {
+  costAnalysis: {
+    costPerCommitAssessment: string | null;
+    costPerLineAssessment: string | null;
+    totalSessionCostUsd: number;
+  };
+  cacheEconomics: {
+    cacheEfficiencyAssessment: string | null;
+    cacheEfficiencyPct: number;
+  };
+  toolUsage: {
+    overallToolHealth: string;
+  };
+  thrashingSignals: {
+    thrashingAssessment: string;
+    bashNearDuplicates: unknown[];
+    editReworkFiles: unknown[];
+  };
+  idleAnalysis: {
+    idleAssessment: string;
+    idlePct: number;
+  };
+  promptQuality: {
+    assessment: string;
+    frictionRate: number;
+  };
+  overview: {
+    contextAssessment: string | null;
+    compactionCount: number;
+  };
+  fileReadRedundancy: {
+    redundancyAssessment: string;
+    readsPerUniqueFile: number;
+  };
+  testProgression: {
+    trajectory: string;
+  };
+}
+
+export function computeTakeaways(report: TakeawayReport): Takeaway[] {
+  const items: Takeaway[] = [];
+
+  // Cost red flags
+  const costSev = assessmentSeverity(report.costAnalysis.costPerCommitAssessment);
+  if (costSev === 'danger') {
+    items.push({
+      severity: 'danger',
+      title: 'High cost per commit',
+      detail: `$${report.costAnalysis.totalSessionCostUsd.toFixed(2)} total \u2014 consider smaller, focused sessions`,
+      sectionTitle: 'Cost Analysis',
+    });
+  } else if (costSev === 'warning') {
+    items.push({
+      severity: 'warning',
+      title: 'Elevated cost per commit',
+      detail: 'Cost per commit is above typical range',
+      sectionTitle: 'Cost Analysis',
+    });
+  }
+
+  // Cache efficiency
+  if (report.cacheEconomics.cacheEfficiencyAssessment === 'concerning') {
+    items.push({
+      severity: 'warning',
+      title: 'Low cache efficiency',
+      detail: `${report.cacheEconomics.cacheEfficiencyPct}% cache hit rate \u2014 prompt structure may reduce caching`,
+      sectionTitle: 'Token Usage',
+    });
+  }
+
+  // Tool health
+  const toolSev = assessmentSeverity(report.toolUsage.overallToolHealth);
+  if (toolSev === 'danger') {
+    items.push({
+      severity: 'danger',
+      title: 'Tool reliability issues',
+      detail: 'Multiple tool calls are failing \u2014 check error section for details',
+      sectionTitle: 'Tool Usage',
+    });
+  } else if (toolSev === 'warning') {
+    items.push({
+      severity: 'warning',
+      title: 'Degraded tool health',
+      detail: 'Some tools have elevated failure rates',
+      sectionTitle: 'Tool Usage',
+    });
+  }
+
+  // Thrashing
+  if (report.thrashingSignals.thrashingAssessment === 'severe') {
+    items.push({
+      severity: 'danger',
+      title: 'Significant thrashing detected',
+      detail: 'Repeated commands and file rework suggest unclear direction',
+      sectionTitle: 'Friction Signals',
+    });
+  } else if (report.thrashingSignals.thrashingAssessment === 'mild') {
+    items.push({
+      severity: 'warning',
+      title: 'Mild thrashing detected',
+      detail: 'Some repeated commands or file rework occurred',
+      sectionTitle: 'Friction Signals',
+    });
+  }
+
+  // Idle time
+  if (report.idleAnalysis.idleAssessment === 'high_idle') {
+    items.push({
+      severity: 'warning',
+      title: 'High idle time',
+      detail: `${report.idleAnalysis.idlePct}% of wall-clock time was idle`,
+      sectionTitle: 'Timeline & Activity',
+    });
+  }
+
+  // Prompt quality
+  const promptSev = assessmentSeverity(report.promptQuality.assessment);
+  if (promptSev === 'danger') {
+    items.push({
+      severity: 'danger',
+      title: 'Prompt quality issues',
+      detail: `${(report.promptQuality.frictionRate * 100).toFixed(0)}% friction rate \u2014 try more detailed initial prompts`,
+      sectionTitle: 'Quality Signals',
+    });
+  }
+
+  // Context pressure
+  if (
+    report.overview.contextAssessment === 'critical' ||
+    report.overview.contextAssessment === 'high'
+  ) {
+    items.push({
+      severity: report.overview.contextAssessment === 'critical' ? 'danger' : 'warning',
+      title: 'Context window pressure',
+      detail: `${report.overview.compactionCount} compaction${report.overview.compactionCount !== 1 ? 's' : ''} occurred \u2014 session may lose early context`,
+      sectionTitle: 'Overview',
+    });
+  }
+
+  // File read redundancy
+  if (report.fileReadRedundancy.redundancyAssessment === 'wasteful') {
+    items.push({
+      severity: 'warning',
+      title: 'Redundant file reads',
+      detail: `${report.fileReadRedundancy.readsPerUniqueFile}x reads per unique file`,
+      sectionTitle: 'Quality Signals',
+    });
+  }
+
+  // Test regression
+  if (report.testProgression.trajectory === 'regressing') {
+    items.push({
+      severity: 'danger',
+      title: 'Tests regressing',
+      detail: 'Test failures increased over the session',
+      sectionTitle: 'Quality Signals',
+    });
+  }
+
+  // Sort by severity (danger first), then limit to 4
+  const severityOrder: Record<Severity, number> = { danger: 0, warning: 1, neutral: 2, good: 3 };
+  items.sort((a, b) => severityOrder[a.severity] - severityOrder[b.severity]);
+
+  if (items.length === 0) {
+    return [
+      {
+        severity: 'good',
+        title: 'Session looks healthy',
+        detail: 'No significant issues detected across all metrics',
+        sectionTitle: 'Overview',
+      },
+    ];
+  }
+
+  return items.slice(0, 4);
+}

src/renderer/utils/stringUtils.ts

@@ -2,6 +2,27 @@
  * String utilities for display formatting.
  */
 
+const isMacPlatform =
+  typeof window !== 'undefined' && window.navigator.userAgent.includes('Macintosh');
+
+/** Returns '⌘' on macOS, 'Ctrl' on Windows/Linux. */
+export const modKey = isMacPlatform ? '⌘' : 'Ctrl+';
+
+/** Returns '⇧' on macOS, 'Shift+' on Windows/Linux. */
+export const shiftKey = isMacPlatform ? '⇧' : 'Shift+';
+
+/**
+ * Formats a keyboard shortcut for the current platform.
+ * @example formatShortcut('R') → '⌘R' on Mac, 'Ctrl+R' on Windows/Linux
+ * @example formatShortcut('W', { shift: true }) → '⇧⌘W' on Mac, 'Ctrl+Shift+W' on Windows/Linux
+ */
+export function formatShortcut(key: string, opts?: { shift?: boolean }): string {
+  if (opts?.shift) {
+    return isMacPlatform ? `${shiftKey}${modKey}${key}` : `${modKey}${shiftKey}${key}`;
+  }
+  return `${modKey}${key}`;
+}
+
 /**
  * Truncates a string in the middle to preserve both the beginning and end.
  * Useful for branch names where the unique identifier is often at the end.

src/shared/types/api.ts

@@ -56,6 +56,30 @@ import type {
   SubagentDetail,
 } from '@main/types';
 
+// =============================================================================
+// Cost Calculation Types
+// =============================================================================
+
+/**
+ * Detailed cost breakdown by token type for a session or chunk
+ */
+export interface CostBreakdown {
+  /** Cost for input tokens */
+  inputCost: number;
+  /** Cost for output tokens */
+  outputCost: number;
+  /** Cost for cache creation tokens */
+  cacheCreationCost: number;
+  /** Cost for cache read tokens */
+  cacheReadCost: number;
+  /** Total cost (sum of all components) */
+  totalCost: number;
+  /** Model name used for calculation */
+  model: string;
+  /** Source of the cost data */
+  source: 'calculated' | 'precalculated' | 'unavailable';
+}
+
 // =============================================================================
 // Agent Config
 // =============================================================================
@@ -492,6 +516,7 @@ export interface ElectronAPI {
     close: () => Promise<void>;
     isMaximized: () => Promise<boolean>;
     isFullScreen: () => Promise<boolean>;
+    relaunch: () => Promise<void>;
   };
 
   /** Subscribe to fullscreen changes (e.g. to remove macOS traffic light padding in fullscreen) */

src/shared/types/notifications.ts

@@ -264,6 +264,10 @@ export interface AppConfig {
     claudeRootPath: string | null;
     /** Agent communication language ('system' = use OS locale) */
     agentLanguage: string;
+    /** Whether to auto-expand AI response groups when opening a transcript or receiving new messages */
+    autoExpandAIGroups: boolean;
+    /** Whether to use the native OS title bar instead of the custom one (Linux/Windows) */
+    useNativeTitleBar: boolean;
   };
   /** Display and UI settings */
   display: {

src/shared/utils/costFormatting.ts

@@ -0,0 +1,45 @@
+/**
+ * Cost formatting utilities
+ */
+
+/**
+ * Format USD cost with appropriate precision
+ * - $0.001 or more: 2 decimal places ($1.23)
+ * - Less than $0.001: 3-4 decimal places for precision ($0.0012)
+ * - Zero: $0.00
+ */
+export function formatCostUsd(cost: number): string {
+  if (cost === 0) {
+    return '$0.00';
+  }
+
+  if (cost >= 0.01) {
+    // Standard currency format for amounts >= 1 cent
+    return `$${cost.toFixed(2)}`;
+  } else if (cost >= 0.001) {
+    // 3 decimal places for sub-cent amounts
+    return `$${cost.toFixed(3)}`;
+  } else {
+    // 4 decimal places for very small amounts
+    return `$${cost.toFixed(4)}`;
+  }
+}
+
+/**
+ * Format cost compactly for display in badges
+ * - Rounds to 2 decimal places
+ * - Omits $ prefix for brevity
+ */
+export function formatCostCompact(cost: number): string {
+  if (cost === 0) {
+    return '0.00';
+  }
+
+  if (cost >= 0.01) {
+    return cost.toFixed(2);
+  } else if (cost >= 0.001) {
+    return cost.toFixed(3);
+  } else {
+    return cost.toFixed(4);
+  }
+}

src/shared/utils/pricing.ts

@@ -0,0 +1,121 @@
+// eslint-disable-next-line no-restricted-imports -- resources/ is outside src/, no alias available
+import pricingData from '../../../resources/pricing.json';
+
+export interface LiteLLMPricing {
+  input_cost_per_token: number;
+  output_cost_per_token: number;
+  cache_creation_input_token_cost?: number;
+  cache_read_input_token_cost?: number;
+  input_cost_per_token_above_200k_tokens?: number;
+  output_cost_per_token_above_200k_tokens?: number;
+  cache_creation_input_token_cost_above_200k_tokens?: number;
+  cache_read_input_token_cost_above_200k_tokens?: number;
+  [key: string]: unknown;
+}
+
+export interface DisplayPricing {
+  input: number;
+  output: number;
+  cache_read: number;
+  cache_creation: number;
+}
+
+const TIER_THRESHOLD = 200_000;
+
+const PRICING_MAP = pricingData as Record<string, unknown>;
+
+// Pre-compute lowercase key map for O(1) case-insensitive lookups
+const LOWERCASE_KEY_MAP = new Map<string, string>();
+for (const key of Object.keys(PRICING_MAP)) {
+  if (!LOWERCASE_KEY_MAP.has(key.toLowerCase())) {
+    LOWERCASE_KEY_MAP.set(key.toLowerCase(), key);
+  }
+}
+
+function isLiteLLMPricing(entry: unknown): entry is LiteLLMPricing {
+  return (
+    !!entry &&
+    typeof entry === 'object' &&
+    'input_cost_per_token' in entry &&
+    'output_cost_per_token' in entry
+  );
+}
+
+function tryGetPricing(key: string): LiteLLMPricing | null {
+  const entry = PRICING_MAP[key];
+  return isLiteLLMPricing(entry) ? entry : null;
+}
+
+export function getPricing(modelName: string): LiteLLMPricing | null {
+  const exact = tryGetPricing(modelName);
+  if (exact) return exact;
+
+  const lowerName = modelName.toLowerCase();
+  const originalKey = LOWERCASE_KEY_MAP.get(lowerName);
+  if (originalKey) {
+    return tryGetPricing(originalKey);
+  }
+
+  return null;
+}
+
+export function calculateTieredCost(tokens: number, baseRate: number, tieredRate?: number): number {
+  if (tokens <= 0) return 0;
+  if (tieredRate == null || tokens <= TIER_THRESHOLD) {
+    return tokens * baseRate;
+  }
+  const costBelow = TIER_THRESHOLD * baseRate;
+  const costAbove = (tokens - TIER_THRESHOLD) * tieredRate;
+  return costBelow + costAbove;
+}
+
+export function calculateMessageCost(
+  modelName: string,
+  inputTokens: number,
+  outputTokens: number,
+  cacheReadTokens: number,
+  cacheCreationTokens: number
+): number {
+  const pricing = getPricing(modelName);
+  if (!pricing) {
+    if (inputTokens > 0 || outputTokens > 0 || cacheReadTokens > 0 || cacheCreationTokens > 0) {
+      console.warn(`[pricing] No pricing data for model "${modelName}", cost will be $0`);
+    }
+    return 0;
+  }
+
+  const inputCost = calculateTieredCost(
+    inputTokens,
+    pricing.input_cost_per_token,
+    pricing.input_cost_per_token_above_200k_tokens
+  );
+  const outputCost = calculateTieredCost(
+    outputTokens,
+    pricing.output_cost_per_token,
+    pricing.output_cost_per_token_above_200k_tokens
+  );
+  const cacheCreationCost = calculateTieredCost(
+    cacheCreationTokens,
+    pricing.cache_creation_input_token_cost ?? 0,
+    pricing.cache_creation_input_token_cost_above_200k_tokens
+  );
+  const cacheReadCost = calculateTieredCost(
+    cacheReadTokens,
+    pricing.cache_read_input_token_cost ?? 0,
+    pricing.cache_read_input_token_cost_above_200k_tokens
+  );
+
+  return inputCost + outputCost + cacheCreationCost + cacheReadCost;
+}
+
+export function getDisplayPricing(modelName: string): DisplayPricing | null {
+  const pricing = getPricing(modelName);
+  if (!pricing) return null;
+
+  return {
+    input: pricing.input_cost_per_token * 1_000_000,
+    output: pricing.output_cost_per_token * 1_000_000,
+    cache_read: (pricing.cache_read_input_token_cost ?? 0) * 1_000_000,
+    cache_creation: (pricing.cache_creation_input_token_cost ?? 0) * 1_000_000,
+  };
+}

test/main/ipc/configValidation.test.ts

@@ -20,6 +20,28 @@ describe('configValidation', () => {
     }
   });
 
+  it('accepts general.autoExpandAIGroups boolean toggle', () => {
+    const resultOn = validateConfigUpdatePayload('general', { autoExpandAIGroups: true });
+    expect(resultOn.valid).toBe(true);
+    if (resultOn.valid) {
+      expect(resultOn.data).toEqual({ autoExpandAIGroups: true });
+    }
+
+    const resultOff = validateConfigUpdatePayload('general', { autoExpandAIGroups: false });
+    expect(resultOff.valid).toBe(true);
+    if (resultOff.valid) {
+      expect(resultOff.data).toEqual({ autoExpandAIGroups: false });
+    }
+  });
+
+  it('rejects non-boolean general.autoExpandAIGroups', () => {
+    const result = validateConfigUpdatePayload('general', { autoExpandAIGroups: 'yes' });
+    expect(result.valid).toBe(false);
+    if (!result.valid) {
+      expect(result.error).toContain('boolean');
+    }
+  });
+
   it('accepts absolute general.claudeRootPath updates', () => {
     const result = validateConfigUpdatePayload('general', {
       claudeRootPath: '/Users/test/.claude',

test/main/utils/costCalculation.test.ts

@@ -0,0 +1,556 @@
+/**
+ * Tests for cost calculation in jsonl.ts
+ */
+
+import { describe, it, expect, vi } from 'vitest';
+import { calculateMetrics } from '@main/utils/jsonl';
+import type { ParsedMessage } from '@main/types';
+
+describe('Cost Calculation', () => {
+  describe('Basic Cost Calculation', () => {
+    it('should calculate cost for simple token usage', () => {
+      const messages: ParsedMessage[] = [
+        {
+          type: 'assistant',
+          uuid: 'msg-1',
+          timestamp: new Date(),
+          content: [],
+          model: 'claude-3-5-sonnet-20241022',
+          usage: {
+            input_tokens: 1000,
+            output_tokens: 500,
+          },
+          toolCalls: [],
+          toolResults: [],
+          isSidechain: false,
+        },
+      ];
+
+      const metrics = calculateMetrics(messages);
+
+      // Expected: (1000 * 0.000003) + (500 * 0.000015) = 0.003 + 0.0075 = 0.0105
+      expect(metrics.costUsd).toBeCloseTo(0.0105, 6);
+    });
+
+    it('should calculate cost with cache tokens', () => {
+      const messages: ParsedMessage[] = [
+        {
+          type: 'assistant',
+          uuid: 'msg-1',
+          timestamp: new Date(),
+          content: [],
+          model: 'claude-3-5-sonnet-20241022',
+          usage: {
+            input_tokens: 1000,
+            output_tokens: 500,
+            cache_creation_input_tokens: 200,
+            cache_read_input_tokens: 300,
+          },
+          toolCalls: [],
+          toolResults: [],
+          isSidechain: false,
+        },
+      ];
+
+      const metrics = calculateMetrics(messages);
+
+      // Input: 1000 * 0.000003 = 0.003
+      // Output: 500 * 0.000015 = 0.0075
+      // Cache creation: 200 * 0.00000375 = 0.00075
+      // Cache read: 300 * 0.0000003 = 0.00009
+      // Total: 0.01134
+      expect(metrics.costUsd).toBeCloseTo(0.01134, 6);
+    });
+
+    it('should return 0 cost when no model is specified', () => {
+      const messages: ParsedMessage[] = [
+        {
+          type: 'assistant',
+          uuid: 'msg-1',
+          timestamp: new Date(),
+          content: [],
+          usage: {
+            input_tokens: 1000,
+            output_tokens: 500,
+          },
+          toolCalls: [],
+          toolResults: [],
+          isSidechain: false,
+        },
+      ];
+
+      const metrics = calculateMetrics(messages);
+      expect(metrics.costUsd).toBe(0);
+    });
+
+    it('should return 0 cost when model pricing not found', () => {
+      const warnSpy = vi.spyOn(console, 'warn').mockImplementation(() => undefined);
+      const messages: ParsedMessage[] = [
+        {
+          type: 'assistant',
+          uuid: 'msg-1',
+          timestamp: new Date(),
+          content: [],
+          model: 'unknown-model',
+          usage: {
+            input_tokens: 1000,
+            output_tokens: 500,
+          },
+          toolCalls: [],
+          toolResults: [],
+          isSidechain: false,
+        },
+      ];
+
+      const metrics = calculateMetrics(messages);
+      expect(metrics.costUsd).toBe(0);
+      warnSpy.mockRestore();
+    });
+  });
+
+  describe('Tiered Pricing', () => {
+    it('should use base rates for tokens below 200k threshold', () => {
+      const messages: ParsedMessage[] = [
+        {
+          type: 'assistant',
+          uuid: 'msg-1',
+          timestamp: new Date(),
+          content: [],
+          model: 'claude-3-5-sonnet-20241022',
+          usage: {
+            input_tokens: 100_000,
+            output_tokens: 50_000,
+          },
+          toolCalls: [],
+          toolResults: [],
+          isSidechain: false,
+        },
+      ];
+
+      const metrics = calculateMetrics(messages);
+
+      // Input: 100000 * 0.000003 = 0.3
+      // Output: 50000 * 0.000015 = 0.75
+      // Total: 1.05
+      expect(metrics.costUsd).toBeCloseTo(1.05, 6);
+    });
+
+    it('should use base rates for input tokens above 200k when model has no tiered pricing', () => {
+      const messages: ParsedMessage[] = [
+        {
+          type: 'assistant',
+          uuid: 'msg-1',
+          timestamp: new Date(),
+          content: [],
+          model: 'claude-3-5-sonnet-20241022',
+          usage: {
+            input_tokens: 250_000,
+            output_tokens: 1_000,
+          },
+          toolCalls: [],
+          toolResults: [],
+          isSidechain: false,
+        },
+      ];
+
+      const metrics = calculateMetrics(messages);
+
+      // claude-3-5-sonnet-20241022 has no tiered rates in pricing.json, so base rates apply
+      // Input: 250000 * 0.000003 = 0.75
+      // Output: 1000 * 0.000015 = 0.015
+      // Total: 0.765
+      expect(metrics.costUsd).toBeCloseTo(0.765, 6);
+    });
+
+    it('should use base rates for output tokens above 200k when model has no tiered pricing', () => {
+      const messages: ParsedMessage[] = [
+        {
+          type: 'assistant',
+          uuid: 'msg-1',
+          timestamp: new Date(),
+          content: [],
+          model: 'claude-3-5-sonnet-20241022',
+          usage: {
+            input_tokens: 1_000,
+            output_tokens: 250_000,
+          },
+          toolCalls: [],
+          toolResults: [],
+          isSidechain: false,
+        },
+      ];
+
+      const metrics = calculateMetrics(messages);
+
+      // No tiered rates, so base rates for all tokens
+      // Input: 1000 * 0.000003 = 0.003
+      // Output: 250000 * 0.000015 = 3.75
+      // Total: 3.753
+      expect(metrics.costUsd).toBeCloseTo(3.753, 6);
+    });
+
+    it('should use base rates for cache tokens above 200k when model has no tiered pricing', () => {
+      const messages: ParsedMessage[] = [
+        {
+          type: 'assistant',
+          uuid: 'msg-1',
+          timestamp: new Date(),
+          content: [],
+          model: 'claude-3-5-sonnet-20241022',
+          usage: {
+            input_tokens: 1_000,
+            output_tokens: 1_000,
+            cache_creation_input_tokens: 250_000,
+            cache_read_input_tokens: 250_000,
+          },
+          toolCalls: [],
+          toolResults: [],
+          isSidechain: false,
+        },
+      ];
+
+      const metrics = calculateMetrics(messages);
+
+      // No tiered rates for this model, so base rates apply
+      // Input: 1000 * 0.000003 = 0.003
+      // Output: 1000 * 0.000015 = 0.015
+      // Cache creation: 250000 * 0.00000375 = 0.9375
+      // Cache read: 250000 * 0.0000003 = 0.075
+      // Total: 1.0305
+      expect(metrics.costUsd).toBeCloseTo(1.0305, 6);
+    });
+
+    it('should handle model without tiered pricing', () => {
+      const messages: ParsedMessage[] = [
+        {
+          type: 'assistant',
+          uuid: 'msg-1',
+          timestamp: new Date(),
+          content: [],
+          model: 'claude-3-opus-20240229',
+          usage: {
+            input_tokens: 250_000,
+            output_tokens: 250_000,
+          },
+          toolCalls: [],
+          toolResults: [],
+          isSidechain: false,
+        },
+      ];
+
+      const metrics = calculateMetrics(messages);
+
+      // No tiered rates, so use base rates even above 200k
+      // Input: 250000 * 0.000015 = 3.75
+      // Output: 250000 * 0.000075 = 18.75
+      // Total: 22.5
+      expect(metrics.costUsd).toBeCloseTo(22.5, 6);
+    });
+
+    it('should use tiered rates for a model that has them (claude-4-sonnet)', () => {
+      const messages: ParsedMessage[] = [
+        {
+          type: 'assistant',
+          uuid: 'msg-1',
+          timestamp: new Date(),
+          content: [],
+          model: 'claude-4-sonnet-20250514',
+          usage: {
+            input_tokens: 250_000,
+            output_tokens: 1_000,
+          },
+          toolCalls: [],
+          toolResults: [],
+          isSidechain: false,
+        },
+      ];
+
+      const metrics = calculateMetrics(messages);
+
+      // claude-4-sonnet has tiered rates:
+      // input base=0.000003, above_200k=0.000006
+      // Input: (200000 * 0.000003) + (50000 * 0.000006) = 0.6 + 0.3 = 0.9
+      // Output: 1000 * 0.000015 = 0.015
+      // Total: 0.915
+      expect(metrics.costUsd).toBeCloseTo(0.915, 6);
+    });
+  });
+
+  describe('Multiple Messages', () => {
+    it('should aggregate costs across multiple messages', () => {
+      const messages: ParsedMessage[] = [
+        {
+          type: 'assistant',
+          uuid: 'msg-1',
+          timestamp: new Date(),
+          content: [],
+          model: 'claude-3-5-sonnet-20241022',
+          usage: {
+            input_tokens: 1000,
+            output_tokens: 500,
+          },
+          toolCalls: [],
+          toolResults: [],
+          isSidechain: false,
+        },
+        {
+          type: 'assistant',
+          uuid: 'msg-2',
+          timestamp: new Date(),
+          content: [],
+          model: 'claude-3-5-sonnet-20241022',
+          usage: {
+            input_tokens: 2000,
+            output_tokens: 1000,
+          },
+          toolCalls: [],
+          toolResults: [],
+          isSidechain: false,
+        },
+      ];
+
+      const metrics = calculateMetrics(messages);
+
+      // Message 1: (1000 * 0.000003) + (500 * 0.000015) = 0.0105
+      // Message 2: (2000 * 0.000003) + (1000 * 0.000015) = 0.021
+      // Total: 0.0315
+      expect(metrics.costUsd).toBeCloseTo(0.0315, 6);
+    });
+
+    it("should calculate cost per-message using each message's model", () => {
+      const messages: ParsedMessage[] = [
+        {
+          type: 'assistant',
+          uuid: 'msg-1',
+          timestamp: new Date(),
+          content: [],
+          model: 'claude-3-5-sonnet-20241022',
+          usage: {
+            input_tokens: 1000,
+            output_tokens: 500,
+          },
+          toolCalls: [],
+          toolResults: [],
+          isSidechain: false,
+        },
+        {
+          type: 'assistant',
+          uuid: 'msg-2',
+          timestamp: new Date(),
+          content: [],
+          model: 'claude-3-opus-20240229', // Different model
+          usage: {
+            input_tokens: 1000,
+            output_tokens: 500,
+          },
+          toolCalls: [],
+          toolResults: [],
+          isSidechain: false,
+        },
+      ];
+
+      const metrics = calculateMetrics(messages);
+
+      // Each message uses its own model's pricing
+      // Message 1 (sonnet): (1000 * 0.000003) + (500 * 0.000015) = 0.003 + 0.0075 = 0.0105
+      // Message 2 (opus): (1000 * 0.000015) + (500 * 0.000075) = 0.015 + 0.0375 = 0.0525
+      // Total cost: 0.0105 + 0.0525 = 0.063
+      expect(metrics.costUsd).toBeCloseTo(0.063, 6);
+    });
+  });
+
+  describe('Edge Cases', () => {
+    it('should handle zero tokens', () => {
+      const messages: ParsedMessage[] = [
+        {
+          type: 'assistant',
+          uuid: 'msg-1',
+          timestamp: new Date(),
+          content: [],
+          model: 'claude-3-5-sonnet-20241022',
+          usage: {
+            input_tokens: 0,
+            output_tokens: 0,
+          },
+          toolCalls: [],
+          toolResults: [],
+          isSidechain: false,
+        },
+      ];
+
+      const metrics = calculateMetrics(messages);
+      expect(metrics.costUsd).toBe(0);
+    });
+
+    it('should handle messages without usage data', () => {
+      const messages: ParsedMessage[] = [
+        {
+          type: 'assistant',
+          uuid: 'msg-1',
+          timestamp: new Date(),
+          content: [],
+          model: 'claude-3-5-sonnet-20241022',
+          toolCalls: [],
+          toolResults: [],
+          isSidechain: false,
+        },
+      ];
+
+      const metrics = calculateMetrics(messages);
+      expect(metrics.costUsd).toBe(0);
+    });
+
+    it('should handle empty messages array', () => {
+      const messages: ParsedMessage[] = [];
+      const metrics = calculateMetrics(messages);
+      expect(metrics.costUsd).toBe(0);
+    });
+  });
+
+  describe('Model Name Lookup', () => {
+    it('should find model with exact match', () => {
+      const messages: ParsedMessage[] = [
+        {
+          type: 'assistant',
+          uuid: 'msg-1',
+          timestamp: new Date(),
+          content: [],
+          model: 'claude-3-5-sonnet-20241022',
+          usage: {
+            input_tokens: 1000,
+            output_tokens: 500,
+          },
+          toolCalls: [],
+          toolResults: [],
+          isSidechain: false,
+        },
+      ];
+
+      const metrics = calculateMetrics(messages);
+      expect(metrics.costUsd).toBeGreaterThan(0);
+    });
+
+    it('should find model with case-insensitive match', () => {
+      const messages: ParsedMessage[] = [
+        {
+          type: 'assistant',
+          uuid: 'msg-1',
+          timestamp: new Date(),
+          content: [],
+          model: 'CLAUDE-3-5-SONNET-20241022',
+          usage: {
+            input_tokens: 1000,
+            output_tokens: 500,
+          },
+          toolCalls: [],
+          toolResults: [],
+          isSidechain: false,
+        },
+      ];
+
+      const metrics = calculateMetrics(messages);
+      expect(metrics.costUsd).toBeGreaterThan(0);
+    });
+  });
+
+  describe('Per-Message Tiering', () => {
+    it('should apply tiered pricing per-message, not to aggregated totals', () => {
+      // Scenario: Many messages each with cache_read tokens < 200k,
+      // but aggregated total > 200k
+      // Each message should use base rates, not tiered rates
+      const messages: ParsedMessage[] = [];
+
+      // Create 10 messages, each with 50k cache_read tokens (500k total)
+      for (let i = 0; i < 10; i++) {
+        messages.push({
+          type: 'assistant',
+          uuid: `msg-${i}`,
+          timestamp: new Date(),
+          content: [],
+          model: 'claude-3-5-sonnet-20241022',
+          usage: {
+            input_tokens: 0,
+            output_tokens: 0,
+            cache_read_input_tokens: 50000,
+          },
+          toolCalls: [],
+          toolResults: [],
+          isSidechain: false,
+        });
+      }
+
+      const metrics = calculateMetrics(messages);
+
+      // Per-message tiering: Each message uses base rate (< 200k threshold)
+      // Each message: 50,000 * 0.0000003 = $0.015
+      // Total: 10 * $0.015 = $0.15
+      const expectedCost = 10 * 50000 * 0.0000003;
+      expect(metrics.costUsd).toBeCloseTo(expectedCost, 6);
+
+      // Verify this is NOT using tiered rate on aggregated total
+      // If incorrectly aggregated: (200k * 0.0000003) + (300k * 0.0000006) = $0.24
+      const incorrectAggregatedCost = 0.24;
+      expect(metrics.costUsd).not.toBeCloseTo(incorrectAggregatedCost, 2);
+    });
+
+    it('should use base rates when individual messages exceed 200k and model has no tiered rates', () => {
+      const messages: ParsedMessage[] = [
+        {
+          type: 'assistant',
+          uuid: 'msg-1',
+          timestamp: new Date(),
+          content: [],
+          model: 'claude-3-5-sonnet-20241022',
+          usage: {
+            input_tokens: 0,
+            output_tokens: 0,
+            cache_read_input_tokens: 300000, // Exceeds 200k threshold
+          },
+          toolCalls: [],
+          toolResults: [],
+          isSidechain: false,
+        },
+      ];
+
+      const metrics = calculateMetrics(messages);
+
+      // No tiered rates for this model, so all 300k at base rate
+      // 300,000 * 0.0000003 = $0.09
+      const expectedCost = 300000 * 0.0000003;
+      expect(metrics.costUsd).toBeCloseTo(expectedCost, 6);
+    });
+  });
+
+  describe('Integration with Other Metrics', () => {
+    it('should include cost alongside other session metrics', () => {
+      const messages: ParsedMessage[] = [
+        {
+          type: 'assistant',
+          uuid: 'msg-1',
+          timestamp: new Date(),
+          content: [],
+          model: 'claude-3-5-sonnet-20241022',
+          usage: {
+            input_tokens: 1000,
+            output_tokens: 500,
+          },
+          toolCalls: [],
+          toolResults: [],
+          isSidechain: false,
+        },
+      ];
+
+      const metrics = calculateMetrics(messages);
+
+      // Check that all expected metrics are present
+      expect(metrics).toHaveProperty('totalTokens');
+      expect(metrics).toHaveProperty('inputTokens');
+      expect(metrics).toHaveProperty('outputTokens');
+      expect(metrics).toHaveProperty('costUsd');
+      expect(metrics.totalTokens).toBe(1500);
+      expect(metrics.inputTokens).toBe(1000);
+      expect(metrics.outputTokens).toBe(500);
+      expect(metrics.costUsd).toBeCloseTo(0.0105, 6);
+    });
+  });
+});

test/renderer/utils/reportAssessments.test.ts

@@ -0,0 +1,398 @@
+import { describe, it, expect } from 'vitest';
+
+import {
+  assessmentColor,
+  assessmentExplanation,
+  assessmentLabel,
+  assessmentSeverity,
+  computeCacheEfficiencyAssessment,
+  computeCacheRatioAssessment,
+  computeCostPerCommitAssessment,
+  computeCostPerLineAssessment,
+  computeIdleAssessment,
+  computeOverheadAssessment,
+  computeRedundancyAssessment,
+  computeSubagentCostShareAssessment,
+  computeTakeaways,
+  computeThrashingAssessment,
+  computeToolHealthAssessment,
+  detectModelMismatch,
+  detectSwitchPattern,
+  severityColor,
+  THRESHOLDS,
+} from '@renderer/utils/reportAssessments';
+
+import type { MetricKey } from '@renderer/utils/reportAssessments';
+
+describe('reportAssessments', () => {
+  describe('severityColor', () => {
+    it('maps severity to hex color', () => {
+      expect(severityColor('good')).toBe('#4ade80');
+      expect(severityColor('warning')).toBe('#fbbf24');
+      expect(severityColor('danger')).toBe('#f87171');
+      expect(severityColor('neutral')).toBe('#a1a1aa');
+    });
+  });
+
+  describe('assessmentSeverity', () => {
+    it('maps known assessments to severity', () => {
+      expect(assessmentSeverity('healthy')).toBe('good');
+      expect(assessmentSeverity('efficient')).toBe('good');
+      expect(assessmentSeverity('expensive')).toBe('warning');
+      expect(assessmentSeverity('red_flag')).toBe('danger');
+      expect(assessmentSeverity('very_high')).toBe('danger');
+      expect(assessmentSeverity('degraded')).toBe('warning');
+      expect(assessmentSeverity('unreliable')).toBe('danger');
+      expect(assessmentSeverity('high_idle')).toBe('danger');
+      expect(assessmentSeverity('moderate')).toBe('warning');
+    });
+
+    it('returns neutral for null/undefined/unknown', () => {
+      expect(assessmentSeverity(null)).toBe('neutral');
+      expect(assessmentSeverity(undefined)).toBe('neutral');
+      expect(assessmentSeverity('unknown_value')).toBe('neutral');
+    });
+  });
+
+  describe('assessmentColor', () => {
+    it('returns correct color for assessment string', () => {
+      expect(assessmentColor('healthy')).toBe('#4ade80');
+      expect(assessmentColor('red_flag')).toBe('#f87171');
+      expect(assessmentColor(null)).toBe('#a1a1aa');
+    });
+  });
+
+  describe('assessmentLabel', () => {
+    it('converts snake_case to Title Case', () => {
+      expect(assessmentLabel('red_flag')).toBe('Red Flag');
+      expect(assessmentLabel('well_specified')).toBe('Well Specified');
+      expect(assessmentLabel('healthy')).toBe('Healthy');
+      expect(assessmentLabel('high_idle')).toBe('High Idle');
+      expect(assessmentLabel('opus_plan_mode')).toBe('Opus Plan Mode');
+    });
+  });
+
+  describe('computeCostPerCommitAssessment', () => {
+    it('returns efficient below threshold', () => {
+      expect(computeCostPerCommitAssessment(0.3)).toBe('efficient');
+    });
+    it('returns normal in range', () => {
+      expect(computeCostPerCommitAssessment(1.0)).toBe('normal');
+    });
+    it('returns expensive in range', () => {
+      expect(computeCostPerCommitAssessment(3.0)).toBe('expensive');
+    });
+    it('returns red_flag above threshold', () => {
+      expect(computeCostPerCommitAssessment(10.0)).toBe('red_flag');
+    });
+    it('respects threshold boundaries', () => {
+      expect(computeCostPerCommitAssessment(THRESHOLDS.costPerCommit.efficient - 0.01)).toBe(
+        'efficient'
+      );
+      expect(computeCostPerCommitAssessment(THRESHOLDS.costPerCommit.efficient)).toBe('normal');
+    });
+  });
+
+  describe('computeCostPerLineAssessment', () => {
+    it('returns efficient below threshold', () => {
+      expect(computeCostPerLineAssessment(0.005)).toBe('efficient');
+    });
+    it('returns red_flag above threshold', () => {
+      expect(computeCostPerLineAssessment(0.5)).toBe('red_flag');
+    });
+  });
+
+  describe('computeSubagentCostShareAssessment', () => {
+    it('returns normal below 30%', () => {
+      expect(computeSubagentCostShareAssessment(20)).toBe('normal');
+    });
+    it('returns high in range', () => {
+      expect(computeSubagentCostShareAssessment(45)).toBe('high');
+    });
+    it('returns very_high in range', () => {
+      expect(computeSubagentCostShareAssessment(70)).toBe('very_high');
+    });
+    it('returns red_flag above 80%', () => {
+      expect(computeSubagentCostShareAssessment(90)).toBe('red_flag');
+    });
+  });
+
+  describe('computeCacheEfficiencyAssessment', () => {
+    it('returns good above 95%', () => {
+      expect(computeCacheEfficiencyAssessment(96)).toBe('good');
+    });
+    it('returns concerning below 95%', () => {
+      expect(computeCacheEfficiencyAssessment(90)).toBe('concerning');
+    });
+  });
+
+  describe('computeCacheRatioAssessment', () => {
+    it('returns good above 20', () => {
+      expect(computeCacheRatioAssessment(25)).toBe('good');
+    });
+    it('returns concerning below 20', () => {
+      expect(computeCacheRatioAssessment(10)).toBe('concerning');
+    });
+  });
+
+  describe('computeToolHealthAssessment', () => {
+    it('returns healthy above 95%', () => {
+      expect(computeToolHealthAssessment(98)).toBe('healthy');
+    });
+    it('returns degraded between 80-95%', () => {
+      expect(computeToolHealthAssessment(85)).toBe('degraded');
+    });
+    it('returns unreliable below 80%', () => {
+      expect(computeToolHealthAssessment(70)).toBe('unreliable');
+    });
+    it('boundary: 95 is degraded, 95.1 is healthy', () => {
+      expect(computeToolHealthAssessment(95)).toBe('degraded');
+      expect(computeToolHealthAssessment(95.1)).toBe('healthy');
+    });
+  });
+
+  describe('computeIdleAssessment', () => {
+    it('returns efficient below 20%', () => {
+      expect(computeIdleAssessment(10)).toBe('efficient');
+    });
+    it('returns moderate between 20-50%', () => {
+      expect(computeIdleAssessment(35)).toBe('moderate');
+    });
+    it('returns high_idle above 50%', () => {
+      expect(computeIdleAssessment(60)).toBe('high_idle');
+    });
+  });
+
+  describe('computeRedundancyAssessment', () => {
+    it('returns normal at or below 2.0', () => {
+      expect(computeRedundancyAssessment(1.5)).toBe('normal');
+      expect(computeRedundancyAssessment(2.0)).toBe('normal');
+    });
+    it('returns wasteful above 2.0', () => {
+      expect(computeRedundancyAssessment(3.0)).toBe('wasteful');
+    });
+  });
+
+  describe('computeOverheadAssessment', () => {
+    it('returns normal at or below 5%', () => {
+      expect(computeOverheadAssessment(3)).toBe('normal');
+      expect(computeOverheadAssessment(5)).toBe('normal');
+    });
+    it('returns heavy above 5%', () => {
+      expect(computeOverheadAssessment(10)).toBe('heavy');
+    });
+  });
+
+  describe('computeThrashingAssessment', () => {
+    it('returns none for 0 signals', () => {
+      expect(computeThrashingAssessment(0)).toBe('none');
+    });
+    it('returns mild for 1-2 signals', () => {
+      expect(computeThrashingAssessment(1)).toBe('mild');
+      expect(computeThrashingAssessment(2)).toBe('mild');
+    });
+    it('returns severe for 3+ signals', () => {
+      expect(computeThrashingAssessment(3)).toBe('severe');
+      expect(computeThrashingAssessment(5)).toBe('severe');
+    });
+  });
+
+  describe('detectModelMismatch', () => {
+    it('returns null for non-opus models', () => {
+      expect(detectModelMismatch('rename files', 'claude-sonnet-4')).toBeNull();
+    });
+
+    it('detects mechanical tasks on opus', () => {
+      const result = detectModelMismatch('rename all variables', 'claude-opus-4');
+      expect(result).not.toBeNull();
+      expect(result!.expectedComplexity).toBe('mechanical');
+    });
+
+    it('detects read-only tasks on opus', () => {
+      const result = detectModelMismatch('explore the codebase', 'claude-opus-4');
+      expect(result).not.toBeNull();
+      expect(result!.expectedComplexity).toBe('read_only');
+    });
+
+    it('returns null for complex tasks on opus', () => {
+      expect(detectModelMismatch('implement authentication system', 'claude-opus-4')).toBeNull();
+    });
+
+    it('detects various mechanical keywords', () => {
+      for (const kw of ['lint', 'format', 'delete', 'move', 'copy', 'replace']) {
+        expect(detectModelMismatch(`${kw} the code`, 'opus')).not.toBeNull();
+      }
+    });
+
+    it('detects various read-only keywords', () => {
+      for (const kw of ['search', 'find', 'verify', 'check', 'scan', 'discover']) {
+        expect(detectModelMismatch(`${kw} for errors`, 'opus')).not.toBeNull();
+      }
+    });
+  });
+
+  describe('detectSwitchPattern', () => {
+    it('returns null for no switches', () => {
+      expect(detectSwitchPattern([])).toBeNull();
+    });
+
+    it('returns manual_switch for single switch', () => {
+      expect(detectSwitchPattern([{ from: 'claude-sonnet-4', to: 'claude-haiku-4' }])).toBe(
+        'manual_switch'
+      );
+    });
+
+    it('detects opus_plan_mode pattern', () => {
+      expect(
+        detectSwitchPattern([
+          { from: 'claude-sonnet-4', to: 'claude-opus-4' },
+          { from: 'claude-opus-4', to: 'claude-sonnet-4' },
+        ])
+      ).toBe('opus_plan_mode');
+    });
+
+    it('returns manual_switch for non-plan-mode switches', () => {
+      expect(
+        detectSwitchPattern([
+          { from: 'claude-sonnet-4', to: 'claude-haiku-4' },
+          { from: 'claude-haiku-4', to: 'claude-sonnet-4' },
+        ])
+      ).toBe('manual_switch');
+    });
+  });
+
+  describe('assessmentExplanation', () => {
+    const ALL_METRIC_ASSESSMENTS: Record<MetricKey, string[]> = {
+      costPerCommit: ['efficient', 'normal', 'expensive', 'red_flag'],
+      costPerLine: ['efficient', 'normal', 'expensive', 'red_flag'],
+      subagentCostShare: ['normal', 'high', 'very_high', 'red_flag'],
+      cacheEfficiency: ['good', 'concerning'],
+      cacheRatio: ['good', 'concerning'],
+      toolHealth: ['healthy', 'degraded', 'unreliable'],
+      idle: ['efficient', 'moderate', 'high_idle'],
+      fileReads: ['normal', 'wasteful'],
+      startup: ['normal', 'heavy'],
+      thrashing: ['none', 'mild', 'severe'],
+      promptQuality: [
+        'well_specified',
+        'moderate_friction',
+        'underspecified',
+        'verbose_but_unclear',
+      ],
+      testTrajectory: ['improving', 'stable', 'regressing', 'insufficient_data'],
+    };
+
+    it('returns non-empty string for all valid metric/assessment combos', () => {
+      for (const [metricKey, assessments] of Object.entries(ALL_METRIC_ASSESSMENTS)) {
+        for (const assessment of assessments) {
+          const result = assessmentExplanation(metricKey as MetricKey, assessment);
+          expect(result, `${metricKey}/${assessment}`).not.toBe('');
+        }
+      }
+    });
+
+    it('returns empty string for unknown combinations', () => {
+      expect(assessmentExplanation('costPerCommit', 'unknown_value')).toBe('');
+      expect(assessmentExplanation('toolHealth' as MetricKey, 'nonexistent')).toBe('');
+    });
+
+    it('includes threshold values in explanations', () => {
+      expect(assessmentExplanation('costPerCommit', 'efficient')).toContain(
+        String(THRESHOLDS.costPerCommit.efficient)
+      );
+      expect(assessmentExplanation('toolHealth', 'healthy')).toContain(
+        String(THRESHOLDS.toolSuccess.healthy)
+      );
+    });
+  });
+
+  describe('computeTakeaways', () => {
+    const healthyReport = {
+      costAnalysis: {
+        costPerCommitAssessment: 'efficient',
+        costPerLineAssessment: 'efficient',
+        totalSessionCostUsd: 0.5,
+      },
+      cacheEconomics: { cacheEfficiencyAssessment: 'good', cacheEfficiencyPct: 97 },
+      toolUsage: { overallToolHealth: 'healthy' },
+      thrashingSignals: {
+        thrashingAssessment: 'none',
+        bashNearDuplicates: [],
+        editReworkFiles: [],
+      },
+      idleAnalysis: { idleAssessment: 'efficient', idlePct: 10 },
+      promptQuality: { assessment: 'well_specified', frictionRate: 0.05 },
+      overview: { contextAssessment: 'healthy', compactionCount: 0 },
+      fileReadRedundancy: { redundancyAssessment: 'normal', readsPerUniqueFile: 1.5 },
+      testProgression: { trajectory: 'improving' },
+    };
+
+    it('returns healthy message when all metrics are good', () => {
+      const result = computeTakeaways(healthyReport);
+      expect(result).toHaveLength(1);
+      expect(result[0].severity).toBe('good');
+      expect(result[0].title).toContain('healthy');
+    });
+
+    it('detects cost red flags', () => {
+      const report = {
+        ...healthyReport,
+        costAnalysis: {
+          ...healthyReport.costAnalysis,
+          costPerCommitAssessment: 'red_flag',
+          totalSessionCostUsd: 15,
+        },
+      };
+      const result = computeTakeaways(report);
+      expect(result.some((t) => t.severity === 'danger' && t.title.includes('cost'))).toBe(true);
+    });
+
+    it('detects thrashing', () => {
+      const report = {
+        ...healthyReport,
+        thrashingSignals: {
+          thrashingAssessment: 'severe',
+          bashNearDuplicates: [{}],
+          editReworkFiles: [],
+        },
+      };
+      const result = computeTakeaways(report);
+      expect(result.some((t) => t.title.includes('thrashing'))).toBe(true);
+    });
+
+    it('limits to 4 takeaways', () => {
+      const report = {
+        ...healthyReport,
+        costAnalysis: {
+          ...healthyReport.costAnalysis,
+          costPerCommitAssessment: 'red_flag',
+          totalSessionCostUsd: 15,
+        },
+        cacheEconomics: { cacheEfficiencyAssessment: 'concerning', cacheEfficiencyPct: 80 },
+        toolUsage: { overallToolHealth: 'unreliable' },
+        thrashingSignals: {
+          thrashingAssessment: 'severe',
+          bashNearDuplicates: [{}],
+          editReworkFiles: [],
+        },
+        promptQuality: { assessment: 'underspecified', frictionRate: 0.5 },
+        overview: { contextAssessment: 'critical', compactionCount: 3 },
+        fileReadRedundancy: { redundancyAssessment: 'wasteful', readsPerUniqueFile: 4 },
+        testProgression: { trajectory: 'regressing' },
+      };
+      const result = computeTakeaways(report);
+      expect(result.length).toBeLessThanOrEqual(4);
+    });
+
+    it('sorts danger before warning', () => {
+      const report = {
+        ...healthyReport,
+        cacheEconomics: { cacheEfficiencyAssessment: 'concerning', cacheEfficiencyPct: 80 },
+        toolUsage: { overallToolHealth: 'unreliable' },
+      };
+      const result = computeTakeaways(report);
+      expect(result.length).toBeGreaterThanOrEqual(2);
+      expect(result[0].severity).toBe('danger');
+    });
+  });
+});

test/shared/utils/costFormatting.test.ts

@@ -0,0 +1,228 @@
+/**
+ * Tests for cost formatting utilities
+ */
+
+import { describe, it, expect } from 'vitest';
+import { formatCostUsd, formatCostCompact } from '@shared/utils/costFormatting';
+
+describe('Cost Formatting', () => {
+  describe('formatCostUsd', () => {
+    describe('Zero values', () => {
+      it('should format zero as $0.00', () => {
+        expect(formatCostUsd(0)).toBe('$0.00');
+      });
+
+      it('should format negative zero as $0.00', () => {
+        expect(formatCostUsd(-0)).toBe('$0.00');
+      });
+    });
+
+    describe('Standard amounts (>= $0.01)', () => {
+      it('should format 1 cent with 2 decimal places', () => {
+        expect(formatCostUsd(0.01)).toBe('$0.01');
+      });
+
+      it('should format 1 dollar with 2 decimal places', () => {
+        expect(formatCostUsd(1.0)).toBe('$1.00');
+      });
+
+      it('should format dollars and cents', () => {
+        expect(formatCostUsd(1.23)).toBe('$1.23');
+      });
+
+      it('should format large amounts', () => {
+        expect(formatCostUsd(999.99)).toBe('$999.99');
+        expect(formatCostUsd(1234.56)).toBe('$1234.56');
+      });
+
+      it('should round to 2 decimal places for amounts >= 1 cent', () => {
+        expect(formatCostUsd(1.234)).toBe('$1.23');
+        expect(formatCostUsd(1.235)).toBe('$1.24'); // Rounds up
+        expect(formatCostUsd(1.999)).toBe('$2.00');
+      });
+    });
+
+    describe('Sub-cent amounts ($0.001 - $0.01)', () => {
+      it('should format 1 tenth of a cent with 3 decimal places', () => {
+        expect(formatCostUsd(0.001)).toBe('$0.001');
+      });
+
+      it('should format sub-cent amounts with 3 decimal places', () => {
+        expect(formatCostUsd(0.005)).toBe('$0.005');
+        expect(formatCostUsd(0.009)).toBe('$0.009');
+      });
+
+      it('should round to 3 decimal places for sub-cent amounts', () => {
+        expect(formatCostUsd(0.0012)).toBe('$0.001');
+        expect(formatCostUsd(0.0015)).toBe('$0.002'); // Rounds up
+        expect(formatCostUsd(0.0099)).toBe('$0.010');
+      });
+    });
+
+    describe('Very small amounts (< $0.001)', () => {
+      it('should format tiny amounts with 4 decimal places', () => {
+        expect(formatCostUsd(0.0001)).toBe('$0.0001');
+        expect(formatCostUsd(0.0005)).toBe('$0.0005');
+        expect(formatCostUsd(0.0009)).toBe('$0.0009');
+      });
+
+      it('should round to 4 decimal places for tiny amounts', () => {
+        expect(formatCostUsd(0.00012)).toBe('$0.0001');
+        expect(formatCostUsd(0.00016)).toBe('$0.0002'); // Rounds up
+        expect(formatCostUsd(0.00099)).toBe('$0.0010');
+      });
+
+      it('should handle very tiny amounts', () => {
+        expect(formatCostUsd(0.000001)).toBe('$0.0000');
+      });
+    });
+
+    describe('Edge cases', () => {
+      it('should handle negative amounts with 4 decimal places', () => {
+        // Negative numbers don't match >= comparisons, so they use 4 decimals
+        expect(formatCostUsd(-1.23)).toBe('$-1.2300');
+        expect(formatCostUsd(-0.001)).toBe('$-0.0010');
+        expect(formatCostUsd(-0.0001)).toBe('$-0.0001');
+      });
+
+      it('should handle very large amounts', () => {
+        expect(formatCostUsd(1000000)).toBe('$1000000.00');
+      });
+
+      it('should handle precision boundaries', () => {
+        // Boundary between 2 and 3 decimal places
+        expect(formatCostUsd(0.01)).toBe('$0.01');
+        expect(formatCostUsd(0.00999)).toBe('$0.010'); // Just below threshold, uses 3 decimals
+
+        // Boundary between 3 and 4 decimal places
+        expect(formatCostUsd(0.001)).toBe('$0.001');
+        expect(formatCostUsd(0.00099)).toBe('$0.0010'); // Just below threshold, uses 4 decimals
+      });
+    });
+
+    describe('Real-world API cost examples', () => {
+      it('should format typical Claude API costs', () => {
+        // 1M input tokens at $3.00/M
+        expect(formatCostUsd(3.0)).toBe('$3.00');
+
+        // 100k input tokens at $3.00/M
+        expect(formatCostUsd(0.3)).toBe('$0.30');
+
+        // 10k cache read tokens at $0.30/M
+        expect(formatCostUsd(0.003)).toBe('$0.003');
+
+        // 1k cache read tokens at $0.30/M
+        expect(formatCostUsd(0.0003)).toBe('$0.0003');
+      });
+
+      it('should format session totals', () => {
+        // Small session
+        expect(formatCostUsd(0.15)).toBe('$0.15');
+
+        // Medium session
+        expect(formatCostUsd(5.67)).toBe('$5.67');
+
+        // Large session
+        expect(formatCostUsd(29.57)).toBe('$29.57');
+      });
+    });
+  });
+
+  describe('formatCostCompact', () => {
+    describe('Zero values', () => {
+      it('should format zero as 0.00', () => {
+        expect(formatCostCompact(0)).toBe('0.00');
+      });
+
+      it('should format negative zero as 0.00', () => {
+        expect(formatCostCompact(-0)).toBe('0.00');
+      });
+    });
+
+    describe('Standard amounts (>= $0.01)', () => {
+      it('should format amounts without $ prefix', () => {
+        expect(formatCostCompact(0.01)).toBe('0.01');
+        expect(formatCostCompact(1.0)).toBe('1.00');
+        expect(formatCostCompact(1.23)).toBe('1.23');
+      });
+
+      it('should format large amounts', () => {
+        expect(formatCostCompact(999.99)).toBe('999.99');
+        expect(formatCostCompact(1234.56)).toBe('1234.56');
+      });
+
+      it('should round to 2 decimal places', () => {
+        expect(formatCostCompact(1.234)).toBe('1.23');
+        expect(formatCostCompact(1.235)).toBe('1.24'); // Rounds up
+        expect(formatCostCompact(1.999)).toBe('2.00');
+      });
+    });
+
+    describe('Sub-cent amounts ($0.001 - $0.01)', () => {
+      it('should format sub-cent amounts with 3 decimal places', () => {
+        expect(formatCostCompact(0.001)).toBe('0.001');
+        expect(formatCostCompact(0.005)).toBe('0.005');
+        expect(formatCostCompact(0.009)).toBe('0.009');
+      });
+
+      it('should round to 3 decimal places', () => {
+        expect(formatCostCompact(0.0012)).toBe('0.001');
+        expect(formatCostCompact(0.0015)).toBe('0.002'); // Rounds up
+        expect(formatCostCompact(0.0099)).toBe('0.010');
+      });
+    });
+
+    describe('Very small amounts (< $0.001)', () => {
+      it('should format tiny amounts with 4 decimal places', () => {
+        expect(formatCostCompact(0.0001)).toBe('0.0001');
+        expect(formatCostCompact(0.0005)).toBe('0.0005');
+        expect(formatCostCompact(0.0009)).toBe('0.0009');
+      });
+
+      it('should round to 4 decimal places', () => {
+        expect(formatCostCompact(0.00012)).toBe('0.0001');
+        expect(formatCostCompact(0.00016)).toBe('0.0002'); // Rounds up
+        expect(formatCostCompact(0.00099)).toBe('0.0010');
+      });
+    });
+
+    describe('Edge cases', () => {
+      it('should handle negative amounts with 4 decimal places', () => {
+        // Negative numbers don't match >= comparisons, so they use 4 decimals
+        expect(formatCostCompact(-1.23)).toBe('-1.2300');
+        expect(formatCostCompact(-0.001)).toBe('-0.0010');
+        expect(formatCostCompact(-0.0001)).toBe('-0.0001');
+      });
+
+      it('should handle very large amounts', () => {
+        expect(formatCostCompact(1000000)).toBe('1000000.00');
+      });
+    });
+
+    describe('Comparison with formatCostUsd', () => {
+      it('should match formatCostUsd except for $ prefix', () => {
+        const testCases = [0, 0.0001, 0.001, 0.01, 1.23, 999.99];
+
+        testCases.forEach((cost) => {
+          const withPrefix = formatCostUsd(cost);
+          const compact = formatCostCompact(cost);
+
+          // Compact should equal the USD format without the $
+          expect(compact).toBe(withPrefix.substring(1));
+        });
+      });
+    });
+
+    describe('Badge display use cases', () => {
+      it('should format for badge display', () => {
+        // Small per-message costs
+        expect(formatCostCompact(0.0015)).toBe('0.002');
+        expect(formatCostCompact(0.01)).toBe('0.01');
+
+        // Session totals in badges
+        expect(formatCostCompact(2.5)).toBe('2.50');
+        expect(formatCostCompact(15.0)).toBe('15.00');
+      });
+    });
+  });
+});

test/shared/utils/pricing.test.ts

@@ -0,0 +1,85 @@
+import { describe, it, expect, vi } from 'vitest';
+import {
+  getPricing,
+  calculateTieredCost,
+  calculateMessageCost,
+  getDisplayPricing,
+} from '@shared/utils/pricing';
+
+describe('Shared Pricing Module', () => {
+  describe('getPricing', () => {
+    it('should find pricing by exact model name', () => {
+      const pricing = getPricing('claude-3-5-sonnet-20241022');
+      expect(pricing).not.toBeNull();
+      expect(pricing!.input_cost_per_token).toBeGreaterThan(0);
+      expect(pricing!.output_cost_per_token).toBeGreaterThan(0);
+    });
+
+    it('should find pricing case-insensitively', () => {
+      const pricing = getPricing('Claude-3-5-Sonnet-20241022');
+      expect(pricing).not.toBeNull();
+    });
+
+    it('should return null for unknown models', () => {
+      const pricing = getPricing('totally-fake-model-xyz');
+      expect(pricing).toBeNull();
+    });
+  });
+
+  describe('calculateTieredCost', () => {
+    it('should use base rate for tokens below 200k', () => {
+      const cost = calculateTieredCost(100_000, 0.000003);
+      expect(cost).toBeCloseTo(0.3, 6);
+    });
+
+    it('should apply tiered rate above 200k', () => {
+      const cost = calculateTieredCost(250_000, 0.000003, 0.000006);
+      expect(cost).toBeCloseTo(0.9, 6);
+    });
+
+    it('should use base rate when no tiered rate provided', () => {
+      const cost = calculateTieredCost(250_000, 0.000015);
+      expect(cost).toBeCloseTo(3.75, 6);
+    });
+
+    it('should return 0 for zero or negative tokens', () => {
+      expect(calculateTieredCost(0, 0.000003)).toBe(0);
+      expect(calculateTieredCost(-100, 0.000003)).toBe(0);
+    });
+  });
+
+  describe('calculateMessageCost', () => {
+    it('should compute cost for a known model', () => {
+      const cost = calculateMessageCost('claude-3-5-sonnet-20241022', 1000, 500, 0, 0);
+      expect(cost).toBeCloseTo(0.0105, 6);
+    });
+
+    it('should return 0 for unknown models', () => {
+      const warnSpy = vi.spyOn(console, 'warn').mockImplementation(() => undefined);
+      const cost = calculateMessageCost('unknown-model', 1000, 500, 0, 0);
+      expect(cost).toBe(0);
+      expect(warnSpy).toHaveBeenCalledWith(
+        '[pricing] No pricing data for model "unknown-model", cost will be $0'
+      );
+      warnSpy.mockRestore();
+    });
+
+    it('should include cache token costs', () => {
+      const cost = calculateMessageCost('claude-3-5-sonnet-20241022', 1000, 500, 300, 200);
+      expect(cost).toBeGreaterThan(0.0105);
+    });
+  });
+
+  describe('getDisplayPricing', () => {
+    it('should return per-million rates for a known model', () => {
+      const dp = getDisplayPricing('claude-3-5-sonnet-20241022');
+      expect(dp).not.toBeNull();
+      expect(dp!.input).toBeCloseTo(3.0, 1);
+      expect(dp!.output).toBeCloseTo(15.0, 1);
+    });
+
+    it('should return null for unknown models', () => {
+      expect(getDisplayPricing('unknown-model')).toBeNull();
+    });
+  });
+});