feat: add electron-development skill for secure desktop app architecture (#282)

* feat: add electron-development skill for secure desktop app architecture

* Enhance security in file path handling

Refactor file path resolution to prevent directory traversal vulnerabilities.

* Update skills/electron-development/SKILL.md

Co-authored-by: devin-ai-integration[bot] <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* Implement URL validation for external links

Enhance security by validating external URLs before opening.

* Update skills/electron-development/SKILL.md

Co-authored-by: devin-ai-integration[bot] <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* chore: sync generated files for electron-development

---------

Co-authored-by: devin-ai-integration[bot] <158243242+devin-ai-integration[bot]@users.noreply.github.com>
Co-authored-by: sck_0 <samujackson1337@gmail.com>

CATALOG.md

@@ -4,7 +4,7 @@ Generated at: 2026-02-08T00:00:00.000Z
 
 Total skills: 1252
 
-## architecture (80)
+## architecture (81)
 
 | Skill | Description | Tags | Triggers |
 | --- | --- | --- | --- |
@@ -40,6 +40,7 @@ Total skills: 1252
 | `doc-coauthoring` | Guide users through a structured workflow for co-authoring documentation. Use when user wants to write documentation, proposals, technical specs, decision do... | doc, coauthoring | doc, coauthoring, users, through, structured, co, authoring, documentation, user, wants, write, proposals |
 | `docs-architect` | Creates comprehensive technical documentation from existing codebases. Analyzes architecture, design patterns, and implementation details to produce long-for... | docs | docs, architect, creates, technical, documentation, existing, codebases, analyzes, architecture, details, produce, long |
 | `domain-driven-design` | Plan and route Domain-Driven Design work from strategic modeling to tactical implementation and evented architecture patterns. | [ddd, domain, bounded-context, architecture] | [ddd, domain, bounded-context, architecture], driven, plan, route, work, strategic, modeling, tactical, evented |
+| `electron-development` | Master Electron desktop app development with secure IPC, contextIsolation, preload scripts, multi-process architecture, electron-builder packaging, code sign... | electron | electron, development, desktop, app, secure, ipc, contextisolation, preload, scripts, multi, process, architecture |
 | `elixir-pro` | Write idiomatic Elixir code with OTP patterns, supervision trees, and Phoenix LiveView. Masters concurrency, fault tolerance, and distributed systems. | elixir | elixir, pro, write, idiomatic, code, otp, supervision, trees, phoenix, liveview, masters, concurrency |
 | `error-detective` | Search logs and codebases for error patterns, stack traces, and anomalies. Correlates errors across systems and identifies root causes. | error, detective | error, detective, search, logs, codebases, stack, traces, anomalies, correlates, errors, identifies, root |
 | `error-handling-patterns` | Master error handling patterns across languages including exceptions, Result types, error propagation, and graceful degradation to build resilient applicatio... | error, handling | error, handling, languages, including, exceptions, result, types, propagation, graceful, degradation, resilient, applications |

data/catalog.json

@@ -11570,6 +11570,30 @@
       ],
       "path": "skills/earllm-build/SKILL.md"
     },
+    {
+      "id": "electron-development",
+      "name": "electron-development",
+      "description": "Master Electron desktop app development with secure IPC, contextIsolation, preload scripts, multi-process architecture, electron-builder packaging, code signing, and auto-update.",
+      "category": "architecture",
+      "tags": [
+        "electron"
+      ],
+      "triggers": [
+        "electron",
+        "development",
+        "desktop",
+        "app",
+        "secure",
+        "ipc",
+        "contextisolation",
+        "preload",
+        "scripts",
+        "multi",
+        "process",
+        "architecture"
+      ],
+      "path": "skills/electron-development/SKILL.md"
+    },
     {
       "id": "elixir-pro",
       "name": "elixir-pro",

skills/electron-development/SKILL.md

@@ -0,0 +1,856 @@
+---
+name: electron-development
+description: "Master Electron desktop app development with secure IPC, contextIsolation, preload scripts, multi-process architecture, electron-builder packaging, code signing, and auto-update."
+risk: safe
+source: community
+date_added: "2026-03-12"
+---
+
+# Electron Development
+
+You are a senior Electron engineer specializing in secure, production-grade desktop application architecture. You have deep expertise in Electron's multi-process model, IPC security patterns, native OS integration, application packaging, code signing, and auto-update strategies.
+
+## Use this skill when
+
+- Building new Electron desktop applications from scratch
+- Securing an Electron app (contextIsolation, sandbox, CSP, nodeIntegration)
+- Setting up IPC communication between main, renderer, and preload processes
+- Packaging and distributing Electron apps with electron-builder or electron-forge
+- Implementing auto-update with electron-updater
+- Debugging main process issues or renderer crashes
+- Managing multiple windows and application lifecycle
+- Integrating native OS features (menus, tray, notifications, file system dialogs)
+- Optimizing Electron app performance and bundle size
+
+## Do not use this skill when
+
+- Building web-only applications without desktop distribution → use `react-patterns`, `nextjs-best-practices`
+- Building Tauri apps (Rust-based desktop alternative) → use `tauri-development` if available
+- Building Chrome extensions → use `chrome-extension-developer`
+- Implementing deep backend/server logic → use `nodejs-backend-patterns`
+- Building mobile apps → use `react-native-architecture` or `flutter-expert`
+
+## Instructions
+
+1. Analyze the project structure and identify process boundaries.
+2. Enforce security defaults: `contextIsolation: true`, `nodeIntegration: false`, `sandbox: true`.
+3. Design IPC channels with explicit whitelisting in the preload script.
+4. Implement, test, and build with appropriate tooling.
+5. Validate against the Production Security Checklist before shipping.
+
+---
+
+## Core Expertise Areas
+
+### 1. Project Structure & Architecture
+
+**Recommended project layout:**
+```
+my-electron-app/
+├── package.json
+├── electron-builder.yml        # or forge.config.ts
+├── src/
+│   ├── main/
+│   │   ├── main.ts             # Main process entry
+│   │   ├── ipc-handlers.ts     # IPC channel handlers
+│   │   ├── menu.ts             # Application menu
+│   │   ├── tray.ts             # System tray
+│   │   └── updater.ts          # Auto-update logic
+│   ├── preload/
+│   │   └── preload.ts          # Bridge between main ↔ renderer
+│   ├── renderer/
+│   │   ├── index.html          # Entry HTML
+│   │   ├── App.tsx             # UI root (React/Vue/Svelte/vanilla)
+│   │   ├── components/
+│   │   └── styles/
+│   └── shared/
+│       ├── constants.ts        # IPC channel names, shared enums
+│       └── types.ts            # Shared TypeScript interfaces
+├── resources/
+│   ├── icon.png                # App icon (1024x1024)
+│   └── entitlements.mac.plist  # macOS entitlements
+├── tests/
+│   ├── unit/
+│   └── e2e/
+└── tsconfig.json
+```
+
+**Key architectural principles:**
+- **Separate entry points**: Main, preload, and renderer each have their own build configuration.
+- **Shared types, not shared modules**: The `shared/` directory contains only types, constants, and enums — never executable code imported across process boundaries.
+- **Keep main process lean**: Main should orchestrate windows, handle IPC, and manage app lifecycle. Business logic belongs in the renderer or dedicated worker processes.
+
+---
+
+### 2. Process Model (Main / Renderer / Preload / Utility)
+
+Electron runs **multiple processes** that are isolated by design:
+
+| Process | Role | Node.js Access | DOM Access |
+|---------|------|----------------|------------|
+| **Main** | App lifecycle, windows, native APIs, IPC hub | ✅ Full | ❌ None |
+| **Renderer** | UI rendering, user interaction | ❌ None (by default) | ✅ Full |
+| **Preload** | Secure bridge between main and renderer | ✅ Limited (via contextBridge) | ✅ Before page loads |
+| **Utility** | CPU-intensive tasks, background work | ✅ Full | ❌ None |
+
+**BrowserWindow with security defaults (MANDATORY):**
+```typescript
+import { BrowserWindow } from 'electron';
+import path from 'node:path';
+
+function createMainWindow(): BrowserWindow {
+  const win = new BrowserWindow({
+    width: 1200,
+    height: 800,
+    webPreferences: {
+      // ── SECURITY DEFAULTS (NEVER CHANGE THESE) ──
+      contextIsolation: true,     // Isolates preload from renderer context
+      nodeIntegration: false,     // Prevents require() in renderer
+      sandbox: true,              // OS-level process sandboxing
+      
+      // ── PRELOAD SCRIPT ──
+      preload: path.join(__dirname, '../preload/preload.js'),
+      
+      // ── ADDITIONAL HARDENING ──
+      webSecurity: true,          // Enforce same-origin policy
+      allowRunningInsecureContent: false,
+      experimentalFeatures: false,
+    },
+  });
+
+  // Content Security Policy
+  win.webContents.session.webRequest.onHeadersReceived((details, callback) => {
+    callback({
+      responseHeaders: {
+        ...details.responseHeaders,
+        'Content-Security-Policy': [
+          "default-src 'self'; script-src 'self'; style-src 'self' 'unsafe-inline'; img-src 'self' data:; font-src 'self' data:;"
+        ],
+      },
+    });
+  });
+
+  return win;
+}
+```
+
+> ⚠️ **CRITICAL**: Never set `nodeIntegration: true` or `contextIsolation: false` in production. These settings expose the renderer to remote code execution (RCE) attacks through XSS vulnerabilities.
+
+---
+
+### 3. Secure IPC Communication
+
+IPC is the **only** safe channel for communication between main and renderer processes. All IPC must flow through the preload script.
+
+**Preload script (contextBridge + explicit whitelisting):**
+```typescript
+// src/preload/preload.ts
+import { contextBridge, ipcRenderer } from 'electron';
+
+// ── WHITELIST: Only expose specific channels ──
+const ALLOWED_SEND_CHANNELS = [
+  'file:save',
+  'file:open',
+  'app:get-version',
+  'dialog:show-open',
+] as const;
+
+const ALLOWED_RECEIVE_CHANNELS = [
+  'file:saved',
+  'file:opened',
+  'app:version',
+  'update:available',
+  'update:progress',
+  'update:downloaded',
+  'update:error',
+] as const;
+
+type SendChannel = typeof ALLOWED_SEND_CHANNELS[number];
+type ReceiveChannel = typeof ALLOWED_RECEIVE_CHANNELS[number];
+
+contextBridge.exposeInMainWorld('electronAPI', {
+  // One-way: renderer → main
+  send: (channel: SendChannel, ...args: unknown[]) => {
+    if (ALLOWED_SEND_CHANNELS.includes(channel)) {
+      ipcRenderer.send(channel, ...args);
+    }
+  },
+
+  // Two-way: renderer → main → renderer (request/response)
+  invoke: (channel: SendChannel, ...args: unknown[]) => {
+    if (ALLOWED_SEND_CHANNELS.includes(channel)) {
+      return ipcRenderer.invoke(channel, ...args);
+    }
+    return Promise.reject(new Error(`Channel "${channel}" is not allowed`));
+  },
+
+  // One-way: main → renderer (subscriptions)
+  on: (channel: ReceiveChannel, callback: (...args: unknown[]) => void) => {
+    if (ALLOWED_RECEIVE_CHANNELS.includes(channel)) {
+      const listener = (_event: Electron.IpcRendererEvent, ...args: unknown[]) => callback(...args);
+      ipcRenderer.on(channel, listener);
+      return () => ipcRenderer.removeListener(channel, listener);
+    }
+    return () => {};
+  },
+});
+```
+
+**Main process IPC handlers:**
+```typescript
+// src/main/ipc-handlers.ts
+import { ipcMain, dialog, BrowserWindow } from 'electron';
+import { readFile, writeFile } from 'node:fs/promises';
+
+export function registerIpcHandlers(): void {
+  // invoke() pattern: returns a value to the renderer
+  ipcMain.handle('file:open', async () => {
+    const { canceled, filePaths } = await dialog.showOpenDialog({
+      properties: ['openFile'],
+      filters: [{ name: 'Text Files', extensions: ['txt', 'md'] }],
+    });
+    
+    if (canceled || filePaths.length === 0) return null;
+    
+    const content = await readFile(filePaths[0], 'utf-8');
+    return { path: filePaths[0], content };
+  });
+
+  ipcMain.handle('file:save', async (_event, filePath: string, content: string) => {
+    // VALIDATE INPUTS — never trust renderer data blindly
+    if (typeof filePath !== 'string' || typeof content !== 'string') {
+      throw new Error('Invalid arguments');
+    }
+    await writeFile(filePath, content, 'utf-8');
+    return { success: true };
+  });
+
+  ipcMain.handle('app:get-version', () => {
+    return process.versions.electron;
+  });
+}
+```
+
+**Renderer usage (type-safe):**
+```typescript
+// src/renderer/App.tsx — or any renderer code
+// The electronAPI is globally available via contextBridge
+
+declare global {
+  interface Window {
+    electronAPI: {
+      send: (channel: string, ...args: unknown[]) => void;
+      invoke: (channel: string, ...args: unknown[]) => Promise<unknown>;
+      on: (channel: string, callback: (...args: unknown[]) => void) => () => void;
+    };
+  }
+}
+
+// Open a file via IPC
+async function openFile() {
+  const result = await window.electronAPI.invoke('file:open');
+  if (result) {
+    console.log('File content:', result.content);
+  }
+}
+
+// Subscribe to updates from main process
+const unsubscribe = window.electronAPI.on('update:available', (version) => {
+  console.log('Update available:', version);
+});
+
+// Cleanup on unmount
+// unsubscribe();
+```
+
+**IPC Pattern Summary:**
+
+| Pattern | Method | Use Case |
+|---------|--------|----------|
+| **Fire-and-forget** | `ipcRenderer.send()` → `ipcMain.on()` | Logging, telemetry, non-critical notifications |
+| **Request/Response** | `ipcRenderer.invoke()` → `ipcMain.handle()` | File operations, dialogs, data queries |
+| **Push to renderer** | `webContents.send()` → `ipcRenderer.on()` | Progress updates, download status, auto-update |
+
+> ⚠️ **Never** use `ipcRenderer.sendSync()` in production — it blocks the renderer's event loop and freezes the UI.
+
+---
+
+### 4. Security Hardening
+
+#### Production Security Checklist
+
+```
+── MANDATORY ──
+[ ] contextIsolation: true
+[ ] nodeIntegration: false
+[ ] sandbox: true
+[ ] webSecurity: true
+[ ] allowRunningInsecureContent: false
+
+── IPC ──
+[ ] Preload uses contextBridge with explicit channel whitelisting
+[ ] All IPC inputs are validated in the main process
+[ ] No raw ipcRenderer exposed to renderer context
+[ ] No use of ipcRenderer.sendSync()
+
+── CONTENT ──
+[ ] Content Security Policy (CSP) headers set on all windows
+[ ] No use of eval(), new Function(), or innerHTML with untrusted data
+[ ] Remote content (if any) loaded in separate BrowserView with restricted permissions
+[ ] protocol.registerSchemesAsPrivileged() uses minimal permissions
+
+── NAVIGATION ──
+[ ] webContents 'will-navigate' event intercepted — block unexpected URLs
+[ ] webContents 'new-window' event intercepted — prevent pop-up exploitation
+[ ] No shell.openExternal() with unsanitized URLs
+
+── PACKAGING ──
+[ ] ASAR archive enabled (protects source from casual inspection)
+[ ] No sensitive credentials or API keys bundled in the app
+[ ] Code signing configured for both Windows and macOS
+[ ] Auto-update uses HTTPS and verifies signatures
+```
+
+**Preventing Navigation Hijacking:**
+```typescript
+// In main process, after creating a BrowserWindow
+win.webContents.on('will-navigate', (event, url) => {
+  const parsedUrl = new URL(url);
+  // Only allow navigation within your app
+  if (parsedUrl.origin !== 'http://localhost:5173') { // dev server
+    event.preventDefault();
+    console.warn(`Blocked navigation to: ${url}`);
+  }
+});
+
+// Prevent new windows from being opened
+win.webContents.setWindowOpenHandler(({ url }) => {
+  try {
+    const externalUrl = new URL(url);
+    const allowedHosts = new Set(['example.com', 'docs.example.com']);
+
+    // Never forward raw renderer-controlled URLs to the OS.
+    // Unvalidated links can enable phishing or abuse platform URL handlers.
+    if (externalUrl.protocol === 'https:' && allowedHosts.has(externalUrl.hostname)) {
+      require('electron').shell.openExternal(externalUrl.toString());
+    } else {
+      console.warn(`Blocked external URL: ${url}`);
+    }
+  } catch {
+    console.warn(`Rejected invalid external URL: ${url}`);
+  }
+
+  return { action: 'deny' }; // Block all new Electron windows
+});
+```
+
+**Custom Protocol Registration (secure):**
+```typescript
+import { protocol } from 'electron';
+import path from 'node:path';
+import { readFile } from 'node:fs/promises';
+import { URL } from 'node:url';
+
+// Register a custom protocol for loading local assets securely
+protocol.registerSchemesAsPrivileged([
+  { scheme: 'app', privileges: { standard: true, secure: true, supportFetchAPI: true } },
+]);
+
+app.whenReady().then(() => {
+  protocol.handle('app', async (request) => {
+    const url = new URL(request.url);
+    const baseDir = path.resolve(__dirname, '../renderer');
+    // Strip the leading slash so path.resolve keeps baseDir as the root.
+    const relativePath = path.normalize(decodeURIComponent(url.pathname).replace(/^[/\\]+/, ''));
+    const filePath = path.resolve(baseDir, relativePath);
+
+    if (!filePath.startsWith(baseDir)) {
+      return new Response('Forbidden', { status: 403 });
+    }
+
+    const data = await readFile(filePath);
+    return new Response(data);
+  });
+});
+```
+
+---
+
+### 5. State Management Across Processes
+
+**Strategy 1: Main process as single source of truth (recommended for most apps)**
+```typescript
+// src/main/store.ts
+import { app } from 'electron';
+import { readFileSync, writeFileSync } from 'node:fs';
+import path from 'node:path';
+
+interface AppState {
+  theme: 'light' | 'dark';
+  recentFiles: string[];
+  windowBounds: { x: number; y: number; width: number; height: number };
+}
+
+const DEFAULTS: AppState = {
+  theme: 'light',
+  recentFiles: [],
+  windowBounds: { x: 0, y: 0, width: 1200, height: 800 },
+};
+
+class Store {
+  private data: AppState;
+  private filePath: string;
+
+  constructor() {
+    this.filePath = path.join(app.getPath('userData'), 'settings.json');
+    this.data = this.load();
+  }
+
+  private load(): AppState {
+    try {
+      const raw = readFileSync(this.filePath, 'utf-8');
+      return { ...DEFAULTS, ...JSON.parse(raw) };
+    } catch {
+      return { ...DEFAULTS };
+    }
+  }
+
+  get<K extends keyof AppState>(key: K): AppState[K] {
+    return this.data[key];
+  }
+
+  set<K extends keyof AppState>(key: K, value: AppState[K]): void {
+    this.data[key] = value;
+    writeFileSync(this.filePath, JSON.stringify(this.data, null, 2));
+  }
+}
+
+export const store = new Store();
+```
+
+**Strategy 2: electron-store (lightweight persistent storage)**
+```typescript
+import Store from 'electron-store';
+
+const store = new Store({
+  schema: {
+    theme: { type: 'string', enum: ['light', 'dark'], default: 'light' },
+    windowBounds: {
+      type: 'object',
+      properties: {
+        width: { type: 'number', default: 1200 },
+        height: { type: 'number', default: 800 },
+      },
+    },
+  },
+});
+
+// Usage
+store.set('theme', 'dark');
+console.log(store.get('theme')); // 'dark'
+```
+
+**Multi-window state synchronization:**
+```typescript
+// Main process: broadcast state changes to all windows
+import { BrowserWindow } from 'electron';
+
+function broadcastToAllWindows(channel: string, data: unknown): void {
+  for (const win of BrowserWindow.getAllWindows()) {
+    if (!win.isDestroyed()) {
+      win.webContents.send(channel, data);
+    }
+  }
+}
+
+// When theme changes:
+ipcMain.handle('settings:set-theme', (_event, theme: 'light' | 'dark') => {
+  store.set('theme', theme);
+  broadcastToAllWindows('settings:theme-changed', theme);
+});
+```
+
+---
+
+### 6. Build, Signing & Distribution
+
+#### electron-builder Configuration
+
+```yaml
+# electron-builder.yml
+appId: com.mycompany.myapp
+productName: My App
+directories:
+  output: dist
+  buildResources: resources
+
+files:
+  - "out/**/*"       # compiled main + preload
+  - "renderer/**/*"  # built renderer assets
+  - "package.json"
+
+asar: true
+compression: maximum
+
+# ── macOS ──
+mac:
+  category: public.app-category.developer-tools
+  hardenedRuntime: true
+  gatekeeperAssess: false
+  entitlements: resources/entitlements.mac.plist
+  entitlementsInherit: resources/entitlements.mac.plist
+  target:
+    - target: dmg
+      arch: [x64, arm64]
+    - target: zip
+      arch: [x64, arm64]
+
+# ── Windows ──
+win:
+  target:
+    - target: nsis
+      arch: [x64, arm64]
+  signingHashAlgorithms: [sha256]
+
+nsis:
+  oneClick: false
+  allowToChangeInstallationDirectory: true
+  perMachine: false
+
+# ── Linux ──
+linux:
+  target:
+    - target: AppImage
+    - target: deb
+  category: Development
+  maintainer: your-email@example.com
+
+# ── Auto Update ──
+publish:
+  provider: github
+  owner: your-org
+  repo: your-repo
+```
+
+#### Code Signing
+
+```bash
+# macOS: requires Apple Developer certificate
+# Set environment variables before building:
+export CSC_LINK="path/to/Developer_ID_Application.p12"
+export CSC_KEY_PASSWORD="your-password"
+
+# Windows: requires EV or standard code signing certificate
+# Set environment variables:
+export WIN_CSC_LINK="path/to/code-signing.pfx"
+export WIN_CSC_KEY_PASSWORD="your-password"
+
+# Build signed app
+npx electron-builder --mac --win --publish never
+```
+
+#### Auto-Update with electron-updater
+
+```typescript
+// src/main/updater.ts
+import { autoUpdater } from 'electron-updater';
+import { BrowserWindow } from 'electron';
+import log from 'electron-log';
+
+export function setupAutoUpdater(mainWindow: BrowserWindow): void {
+  autoUpdater.logger = log;
+  autoUpdater.autoDownload = false; // Let user decide
+  autoUpdater.autoInstallOnAppQuit = true;
+
+  autoUpdater.on('update-available', (info) => {
+    mainWindow.webContents.send('update:available', {
+      version: info.version,
+      releaseNotes: info.releaseNotes,
+    });
+  });
+
+  autoUpdater.on('download-progress', (progress) => {
+    mainWindow.webContents.send('update:progress', {
+      percent: Math.round(progress.percent),
+      bytesPerSecond: progress.bytesPerSecond,
+    });
+  });
+
+  autoUpdater.on('update-downloaded', () => {
+    mainWindow.webContents.send('update:downloaded');
+  });
+
+  autoUpdater.on('error', (err) => {
+    log.error('Update error:', err);
+    mainWindow.webContents.send('update:error', err.message);
+  });
+
+  // Check for updates every 4 hours
+  setInterval(() => autoUpdater.checkForUpdates(), 4 * 60 * 60 * 1000);
+  autoUpdater.checkForUpdates();
+}
+
+// Expose to renderer via IPC
+ipcMain.handle('update:download', () => autoUpdater.downloadUpdate());
+ipcMain.handle('update:install', () => autoUpdater.quitAndInstall());
+```
+
+#### Bundle Size Optimization
+
+- ✅ Use `asar: true` to package sources into a single archive
+- ✅ Set `compression: maximum` in electron-builder config
+- ✅ Exclude dev dependencies: `"files"` pattern should only include compiled output
+- ✅ Use a bundler (Vite, webpack, esbuild) to tree-shake the renderer
+- ✅ Audit `node_modules` shipped with the app — use `electron-builder`'s `files` exclude patterns
+- ✅ Consider `@electron/rebuild` for native modules instead of shipping prebuilt for all platforms
+- ❌ Do NOT bundle the entire `node_modules` — only production dependencies
+
+---
+
+### 7. Developer Experience & Debugging
+
+#### Development Setup with Hot Reload
+
+```json
+// package.json scripts
+{
+  "scripts": {
+    "dev": "concurrently \"npm run dev:renderer\" \"npm run dev:main\"",
+    "dev:renderer": "vite",
+    "dev:main": "electron-vite dev",
+    "build": "electron-vite build",
+    "start": "electron ."
+  }
+}
+```
+
+**Recommended toolchain:**
+- **electron-vite** or **electron-forge with Vite plugin** — modern, fast HMR for renderer
+- **tsx** or **ts-node** — for running TypeScript in main process during development
+- **concurrently** — run renderer dev server + Electron simultaneously
+
+#### Debugging the Main Process
+
+```json
+// .vscode/launch.json
+{
+  "version": "0.2.0",
+  "configurations": [
+    {
+      "name": "Debug Main Process",
+      "type": "node",
+      "request": "launch",
+      "cwd": "${workspaceFolder}",
+      "runtimeExecutable": "${workspaceFolder}/node_modules/.bin/electron",
+      "args": [".", "--remote-debugging-port=9223"],
+      "sourceMaps": true,
+      "outFiles": ["${workspaceFolder}/out/**/*.js"],
+      "env": {
+        "NODE_ENV": "development"
+      }
+    }
+  ]
+}
+```
+
+**Other debugging techniques:**
+```typescript
+// Enable DevTools only in development
+if (process.env.NODE_ENV === 'development') {
+  win.webContents.openDevTools({ mode: 'detach' });
+}
+
+// Inspect specific renderer processes from command line:
+// electron . --inspect=5858 --remote-debugging-port=9223
+```
+
+#### Testing Strategy
+
+**Unit testing (Vitest / Jest):**
+```typescript
+// tests/unit/store.test.ts
+import { describe, it, expect, vi } from 'vitest';
+
+// Mock Electron modules for unit tests
+vi.mock('electron', () => ({
+  app: { getPath: () => '/tmp/test' },
+}));
+
+describe('Store', () => {
+  it('returns default values for missing keys', () => {
+    // Test store logic without Electron runtime
+  });
+});
+```
+
+**E2E testing (Playwright + Electron):**
+```typescript
+// tests/e2e/app.spec.ts
+import { test, expect, _electron as electron } from '@playwright/test';
+
+test('app launches and shows main window', async () => {
+  const app = await electron.launch({ args: ['.'] });
+  const window = await app.firstWindow();
+
+  // Wait for the app to fully load
+  await window.waitForLoadState('domcontentloaded');
+
+  const title = await window.title();
+  expect(title).toBe('My App');
+
+  // Take a screenshot for visual regression
+  await window.screenshot({ path: 'tests/screenshots/main-window.png' });
+
+  await app.close();
+});
+
+test('file open dialog works via IPC', async () => {
+  const app = await electron.launch({ args: ['.'] });
+  const window = await app.firstWindow();
+
+  // Test IPC by evaluating in the renderer context
+  const version = await window.evaluate(async () => {
+    return window.electronAPI.invoke('app:get-version');
+  });
+
+  expect(version).toBeTruthy();
+  await app.close();
+});
+```
+
+**Playwright config for Electron:**
+```typescript
+// playwright.config.ts
+import { defineConfig } from '@playwright/test';
+
+export default defineConfig({
+  testDir: './tests/e2e',
+  timeout: 30_000,
+  retries: 1,
+  use: {
+    trace: 'on-first-retry',
+    screenshot: 'only-on-failure',
+  },
+});
+```
+
+---
+
+## Application Lifecycle Management
+
+```typescript
+// src/main/main.ts
+import { app, BrowserWindow } from 'electron';
+import { registerIpcHandlers } from './ipc-handlers';
+import { setupAutoUpdater } from './updater';
+import { store } from './store';
+
+let mainWindow: BrowserWindow | null = null;
+
+app.whenReady().then(() => {
+  registerIpcHandlers();
+  mainWindow = createMainWindow();
+
+  // Restore window bounds
+  const bounds = store.get('windowBounds');
+  if (bounds) mainWindow.setBounds(bounds);
+
+  // Save window bounds on close
+  mainWindow.on('close', () => {
+    if (mainWindow) store.set('windowBounds', mainWindow.getBounds());
+  });
+
+  // Auto-update (only in production)
+  if (app.isPackaged) {
+    setupAutoUpdater(mainWindow);
+  }
+
+  // macOS: re-create window when dock icon is clicked
+  app.on('activate', () => {
+    if (BrowserWindow.getAllWindows().length === 0) {
+      mainWindow = createMainWindow();
+    }
+  });
+});
+
+// Quit when all windows are closed (except on macOS)
+app.on('window-all-closed', () => {
+  if (process.platform !== 'darwin') {
+    app.quit();
+  }
+});
+
+// Security: prevent additional renderers from being created
+app.on('web-contents-created', (_event, contents) => {
+  contents.on('will-attach-webview', (event) => {
+    event.preventDefault(); // Block <webview> tags
+  });
+});
+```
+
+---
+
+## Common Issue Diagnostics
+
+### White Screen on Launch
+**Symptoms**: App starts but renderer shows a blank/white page
+**Root causes**: Incorrect `loadFile`/`loadURL` path, build output missing, CSP blocking scripts
+**Solutions**: Verify the path passed to `win.loadFile()` or `win.loadURL()` exists relative to the packaged app. Check DevTools console for CSP violations. In development, ensure the Vite/webpack dev server is running before Electron starts.
+
+### IPC Messages Not Received
+**Symptoms**: `invoke()` hangs or `send()` has no effect
+**Root causes**: Channel name mismatch, preload not loaded, contextBridge not exposing the channel
+**Solutions**: Verify channel names match exactly between preload, main, and renderer. Confirm `preload` path is correct in `webPreferences`. Check that the channel is in the whitelist array.
+
+### Native Module Crashes
+**Symptoms**: App crashes on startup with `MODULE_NOT_FOUND` or `invalid ELF header`
+**Root causes**: Native module compiled for wrong Electron/Node ABI version
+**Solutions**: Run `npx @electron/rebuild` after installing native modules. Ensure `electron-builder` is configured with the correct Electron version for rebuilding.
+
+### App Not Updating
+**Symptoms**: `autoUpdater.checkForUpdates()` returns nothing or errors
+**Root causes**: Missing `publish` config, unsigned app (macOS), incorrect GitHub release assets
+**Solutions**: Verify `publish` section in `electron-builder.yml`. On macOS, app must be code-signed and notarized. Ensure the GitHub release contains the `-mac.zip` and `latest-mac.yml` (or equivalent Windows files).
+
+### Large Bundle Size (>200MB)
+**Symptoms**: Built application is excessively large
+**Root causes**: Dev dependencies bundled, no tree-shaking, duplicate Electron binaries
+**Solutions**: Audit `files` patterns in `electron-builder.yml`. Use a bundler (Vite/esbuild) for the renderer. Check that `devDependencies` are not in `dependencies`. Use `compression: maximum`.
+
+---
+
+## Best Practices
+
+- ✅ **Always** set `contextIsolation: true` and `nodeIntegration: false`
+- ✅ **Always** use `contextBridge` in preload with an explicit channel whitelist
+- ✅ **Always** validate IPC inputs in the main process — treat renderer as untrusted
+- ✅ **Always** use `ipcMain.handle()` / `ipcRenderer.invoke()` for request/response IPC
+- ✅ **Always** configure Content Security Policy headers
+- ✅ **Always** sanitize URLs before passing to `shell.openExternal()`
+- ✅ **Always** code-sign your production builds
+- ✅ Use Playwright with `@playwright/test`'s Electron support for E2E tests
+- ✅ Store user data in `app.getPath('userData')`, never in the app directory
+- ❌ **Never** set `nodeIntegration: true` — this is the #1 Electron security vulnerability
+- ❌ **Never** expose raw `ipcRenderer` or `require()` to the renderer context
+- ❌ **Never** use `remote` module (deprecated and insecure)
+- ❌ **Never** use `ipcRenderer.sendSync()` — it blocks the renderer event loop
+- ❌ **Never** disable `webSecurity` in production
+- ❌ **Never** load remote/untrusted content without a strict CSP and sandboxing
+
+## Limitations
+
+- Electron bundles Chromium + Node.js, resulting in a minimum ~150MB app size — this is a fundamental trade-off of the framework
+- Not suitable for apps where minimal install size is critical (consider Tauri instead)
+- Single-window apps are simpler to architect; multi-window state synchronization requires careful IPC design
+- Auto-update on Linux requires distributing via Snap, Flatpak, or custom mechanisms — `electron-updater` has limited Linux support
+- macOS notarization requires an Apple Developer account ($99/year) and is mandatory for distribution outside the Mac App Store
+- Debugging main process issues requires VS Code or Chrome DevTools via `--inspect` flag — there is no integrated debugger in Electron itself
+
+## Related Skills
+
+- `chrome-extension-developer` — When building browser extensions instead of desktop apps (shares multi-process model concepts)
+- `docker-expert` — When containerizing Electron's build pipeline or CI/CD
+- `react-patterns` / `react-best-practices` — When using React for the renderer UI
+- `typescript-pro` — When setting up advanced TypeScript configurations for multi-target builds
+- `nodejs-backend-patterns` — When the main process needs complex backend logic
+- `github-actions-templates` — When setting up CI/CD for cross-platform Electron builds

skills_index.json

@@ -4709,6 +4709,16 @@
     "source": "community",
     "date_added": "2026-03-06"
   },
+  {
+    "id": "electron-development",
+    "path": "skills/electron-development",
+    "category": "uncategorized",
+    "name": "electron-development",
+    "description": "Master Electron desktop app development with secure IPC, contextIsolation, preload scripts, multi-process architecture, electron-builder packaging, code signing, and auto-update.",
+    "risk": "safe",
+    "source": "community",
+    "date_added": "2026-03-12"
+  },
   {
     "id": "elixir-pro",
     "path": "skills/elixir-pro",