diff --git a/.env.example b/.env.example
index b0747a61..e12c4c67 100644
--- a/.env.example
+++ b/.env.example
@@ -9,4 +9,6 @@ APPLE_CODESIGN_KEYCHAIN_PASSWORD="xxx"
 
 VITE_POSTHOG_API_KEY=xxx
 VITE_POSTHOG_API_HOST=xxx
-VITE_POSTHOG_UI_HOST=xxx
\ No newline at end of file
+VITE_POSTHOG_UI_HOST=xxx
+
+VITE_DEV_ERROR_TOASTS=true
diff --git a/apps/array/package.json b/apps/array/package.json
index bc00d5de..b58837da 100644
--- a/apps/array/package.json
+++ b/apps/array/package.json
@@ -138,6 +138,7 @@
     "radix-themes-tw": "0.2.3",
     "react": "^18.2.0",
     "react-dom": "^18.2.0",
+    "react-error-boundary": "^6.0.0",
     "react-hook-form": "^7.64.0",
     "react-hotkeys-hook": "^4.4.4",
     "react-markdown": "^10.1.0",
diff --git a/apps/array/src/main/di/container.ts b/apps/array/src/main/di/container.ts
index 1c7ba0e1..52d7176f 100644
--- a/apps/array/src/main/di/container.ts
+++ b/apps/array/src/main/di/container.ts
@@ -14,6 +14,7 @@ import { ShellService } from "../services/shell/service.js";
 import { TaskLinkService } from "../services/task-link/service.js";
 import { UIService } from "../services/ui/service.js";
 import { UpdatesService } from "../services/updates/service.js";
+import { UserNotificationService } from "../services/user-notification/service.js";
 import { WorkspaceService } from "../services/workspace/service.js";
 import { MAIN_TOKENS } from "./tokens.js";
 
@@ -35,4 +36,5 @@ container.bind(MAIN_TOKENS.ShellService).to(ShellService);
 container.bind(MAIN_TOKENS.UIService).to(UIService);
 container.bind(MAIN_TOKENS.UpdatesService).to(UpdatesService);
 container.bind(MAIN_TOKENS.TaskLinkService).to(TaskLinkService);
+container.bind(MAIN_TOKENS.UserNotificationService).to(UserNotificationService);
 container.bind(MAIN_TOKENS.WorkspaceService).to(WorkspaceService);
diff --git a/apps/array/src/main/di/tokens.ts b/apps/array/src/main/di/tokens.ts
index b6822ba7..101d337c 100644
--- a/apps/array/src/main/di/tokens.ts
+++ b/apps/array/src/main/di/tokens.ts
@@ -21,4 +21,5 @@ export const MAIN_TOKENS = Object.freeze({
   UpdatesService: Symbol.for("Main.UpdatesService"),
   TaskLinkService: Symbol.for("Main.TaskLinkService"),
   WorkspaceService: Symbol.for("Main.WorkspaceService"),
+  UserNotificationService: Symbol.for("Main.UserNotificationService"),
 });
diff --git a/apps/array/src/main/index.ts b/apps/array/src/main/index.ts
index b7f775b5..e6ee5466 100644
--- a/apps/array/src/main/index.ts
+++ b/apps/array/src/main/index.ts
@@ -13,6 +13,10 @@ import { mkdirSync } from "node:fs";
 import os from "node:os";
 import path from "node:path";
 import { fileURLToPath } from "node:url";
+import { initializeMainErrorHandling } from "./lib/error-handling.js";
+
+initializeMainErrorHandling();
+
 import { createIPCHandler } from "@posthog/electron-trpc/main";
 import {
   app,
diff --git a/apps/array/src/main/lib/error-handling.ts b/apps/array/src/main/lib/error-handling.ts
new file mode 100644
index 00000000..94b27805
--- /dev/null
+++ b/apps/array/src/main/lib/error-handling.ts
@@ -0,0 +1,20 @@
+import { ipcMain } from "electron";
+import { logger } from "./logger.js";
+
+export function initializeMainErrorHandling(): void {
+  process.on("uncaughtException", (error) => {
+    logger.error("Uncaught exception", error);
+  });
+
+  process.on("unhandledRejection", (reason) => {
+    const error = reason instanceof Error ? reason : new Error(String(reason));
+    logger.error("Unhandled rejection", error);
+  });
+
+  ipcMain.on(
+    "preload-error",
+    (_, error: { message: string; stack?: string }) => {
+      logger.error("Preload error", error);
+    },
+  );
+}
diff --git a/apps/array/src/main/lib/logger.ts b/apps/array/src/main/lib/logger.ts
index 349797ec..50a3002a 100644
--- a/apps/array/src/main/lib/logger.ts
+++ b/apps/array/src/main/lib/logger.ts
@@ -1,37 +1,15 @@
+import type { Logger, ScopedLogger } from "@shared/lib/create-logger.js";
+import { createLogger } from "@shared/lib/create-logger.js";
 import { app } from "electron";
 import log from "electron-log/main";
 
-// Initialize IPC transport to forward main process logs to renderer dev tools
 log.initialize();
 
-// Set levels - use debug in dev (check NODE_ENV since app.isPackaged may not be ready)
 const isDev = process.env.NODE_ENV === "development" || !app.isPackaged;
 const level = isDev ? "debug" : "info";
 log.transports.file.level = level;
 log.transports.console.level = level;
-// IPC transport needs level set separately
 log.transports.ipc.level = level;
 
-export const logger = {
-  info: (message: string, ...args: unknown[]) => log.info(message, ...args),
-  warn: (message: string, ...args: unknown[]) => log.warn(message, ...args),
-  error: (message: string, ...args: unknown[]) => log.error(message, ...args),
-  debug: (message: string, ...args: unknown[]) => log.debug(message, ...args),
-
-  scope: (name: string) => {
-    const scoped = log.scope(name);
-    return {
-      info: (message: string, ...args: unknown[]) =>
-        scoped.info(message, ...args),
-      warn: (message: string, ...args: unknown[]) =>
-        scoped.warn(message, ...args),
-      error: (message: string, ...args: unknown[]) =>
-        scoped.error(message, ...args),
-      debug: (message: string, ...args: unknown[]) =>
-        scoped.debug(message, ...args),
-    };
-  },
-};
-
-export type Logger = typeof logger;
-export type ScopedLogger = ReturnType<typeof logger.scope>;
+export const logger = createLogger(log);
+export type { Logger, ScopedLogger };
diff --git a/apps/array/src/main/preload.ts b/apps/array/src/main/preload.ts
index 88f4dfa9..3ca78264 100644
--- a/apps/array/src/main/preload.ts
+++ b/apps/array/src/main/preload.ts
@@ -1,6 +1,23 @@
 import { exposeElectronTRPC } from "@posthog/electron-trpc/main";
+import { ipcRenderer } from "electron";
 import "electron-log/preload";
 
+// No TRPC available, so just use IPC
+process.on("uncaughtException", (error) => {
+  ipcRenderer.send("preload-error", {
+    message: error.message,
+    stack: error.stack,
+  });
+});
+
+process.on("unhandledRejection", (reason) => {
+  const error = reason instanceof Error ? reason : new Error(String(reason));
+  ipcRenderer.send("preload-error", {
+    message: error.message,
+    stack: error.stack,
+  });
+});
+
 process.once("loaded", async () => {
   exposeElectronTRPC();
 });
diff --git a/apps/array/src/main/services/user-notification/schemas.ts b/apps/array/src/main/services/user-notification/schemas.ts
new file mode 100644
index 00000000..f4228e6b
--- /dev/null
+++ b/apps/array/src/main/services/user-notification/schemas.ts
@@ -0,0 +1,15 @@
+export const UserNotificationEvent = {
+  Notify: "notify",
+} as const;
+
+export type NotificationSeverity = "error" | "warning" | "info";
+
+export interface UserNotificationPayload {
+  severity: NotificationSeverity;
+  title: string;
+  description?: string;
+}
+
+export interface UserNotificationEvents {
+  [UserNotificationEvent.Notify]: UserNotificationPayload;
+}
diff --git a/apps/array/src/main/services/user-notification/service.ts b/apps/array/src/main/services/user-notification/service.ts
new file mode 100644
index 00000000..808153ad
--- /dev/null
+++ b/apps/array/src/main/services/user-notification/service.ts
@@ -0,0 +1,46 @@
+import { app } from "electron";
+import { injectable, postConstruct } from "inversify";
+import { logger } from "../../lib/logger.js";
+import { TypedEventEmitter } from "../../lib/typed-event-emitter.js";
+import {
+  UserNotificationEvent,
+  type UserNotificationEvents,
+} from "./schemas.js";
+
+const isDev = process.env.NODE_ENV === "development" || !app.isPackaged;
+const devErrorToastsEnabled =
+  isDev && process.env.VITE_DEV_ERROR_TOASTS !== "false";
+
+@injectable()
+export class UserNotificationService extends TypedEventEmitter<UserNotificationEvents> {
+  @postConstruct()
+  init(): void {
+    if (devErrorToastsEnabled) {
+      logger.setDevToastEmitter((title, desc) => this.error(title, desc));
+    }
+  }
+
+  error(title: string, description?: string): void {
+    this.emit(UserNotificationEvent.Notify, {
+      severity: "error",
+      title,
+      description,
+    });
+  }
+
+  warning(title: string, description?: string): void {
+    this.emit(UserNotificationEvent.Notify, {
+      severity: "warning",
+      title,
+      description,
+    });
+  }
+
+  info(title: string, description?: string): void {
+    this.emit(UserNotificationEvent.Notify, {
+      severity: "info",
+      title,
+      description,
+    });
+  }
+}
diff --git a/apps/array/src/main/trpc/router.ts b/apps/array/src/main/trpc/router.ts
index cc19c226..6749e23b 100644
--- a/apps/array/src/main/trpc/router.ts
+++ b/apps/array/src/main/trpc/router.ts
@@ -16,6 +16,7 @@ import { secureStoreRouter } from "./routers/secure-store.js";
 import { shellRouter } from "./routers/shell.js";
 import { uiRouter } from "./routers/ui.js";
 import { updatesRouter } from "./routers/updates.js";
+import { userNotificationRouter } from "./routers/user-notification.js";
 import { workspaceRouter } from "./routers/workspace.js";
 import { router } from "./trpc.js";
 
@@ -37,6 +38,7 @@ export const trpcRouter = router({
   shell: shellRouter,
   ui: uiRouter,
   updates: updatesRouter,
+  userNotification: userNotificationRouter,
   deepLink: deepLinkRouter,
   workspace: workspaceRouter,
 });
diff --git a/apps/array/src/main/trpc/routers/user-notification.ts b/apps/array/src/main/trpc/routers/user-notification.ts
new file mode 100644
index 00000000..25083d43
--- /dev/null
+++ b/apps/array/src/main/trpc/routers/user-notification.ts
@@ -0,0 +1,20 @@
+import { container } from "../../di/container.js";
+import { MAIN_TOKENS } from "../../di/tokens.js";
+import { UserNotificationEvent } from "../../services/user-notification/schemas.js";
+import type { UserNotificationService } from "../../services/user-notification/service.js";
+import { publicProcedure, router } from "../trpc.js";
+
+const getService = () =>
+  container.get<UserNotificationService>(MAIN_TOKENS.UserNotificationService);
+
+export const userNotificationRouter = router({
+  onNotify: publicProcedure.subscription(async function* (opts) {
+    const service = getService();
+    const iterable = service.toIterable(UserNotificationEvent.Notify, {
+      signal: opts.signal,
+    });
+    for await (const data of iterable) {
+      yield data;
+    }
+  }),
+});
diff --git a/apps/array/src/renderer/App.tsx b/apps/array/src/renderer/App.tsx
index c4595084..75b21e0a 100644
--- a/apps/array/src/renderer/App.tsx
+++ b/apps/array/src/renderer/App.tsx
@@ -1,10 +1,10 @@
+import { ErrorBoundary } from "@components/ErrorBoundary";
 import { MainLayout } from "@components/MainLayout";
 import { AuthScreen } from "@features/auth/components/AuthScreen";
 import { useAuthStore } from "@features/auth/stores/authStore";
+import { useUserNotifications } from "@hooks/useUserNotifications";
 import { Flex, Spinner, Text } from "@radix-ui/themes";
 import { initializePostHog } from "@renderer/lib/analytics";
-import { trpcVanilla } from "@renderer/trpc/client";
-import { toast } from "@utils/toast";
 import { useEffect, useState } from "react";
 
 function App() {
@@ -16,15 +16,8 @@ function App() {
     initializePostHog();
   }, []);
 
-  // Global workspace error listener for toasts
-  useEffect(() => {
-    const subscription = trpcVanilla.workspace.onError.subscribe(undefined, {
-      onData: (data) => {
-        toast.error("Workspace error", { description: data.message });
-      },
-    });
-    return () => subscription.unsubscribe();
-  }, []);
+  // Global notification listener - handles all main process notifications
+  useUserNotifications();
 
   useEffect(() => {
     initializeOAuth().finally(() => setIsLoading(false));
@@ -41,7 +34,11 @@ function App() {
     );
   }
 
-  return isAuthenticated ? <MainLayout /> : <AuthScreen />;
+  return (
+    <ErrorBoundary>
+      {isAuthenticated ? <MainLayout /> : <AuthScreen />}
+    </ErrorBoundary>
+  );
 }
 
 export default App;
diff --git a/apps/array/src/api/posthogClient.ts b/apps/array/src/renderer/api/posthogClient.ts
similarity index 98%
rename from apps/array/src/api/posthogClient.ts
rename to apps/array/src/renderer/api/posthogClient.ts
index 23c1acc8..ff806f75 100644
--- a/apps/array/src/api/posthogClient.ts
+++ b/apps/array/src/renderer/api/posthogClient.ts
@@ -1,9 +1,9 @@
+import { buildApiFetcher } from "@api/fetcher";
+import { createApiClient, type Schemas } from "@api/generated";
 import type { AgentEvent } from "@posthog/agent";
 import { logger } from "@renderer/lib/logger";
 import type { Task, TaskRun } from "@shared/types";
 import type { StoredLogEntry } from "@shared/types/session-events";
-import { buildApiFetcher } from "./fetcher";
-import { createApiClient, type Schemas } from "./generated";
 
 const log = logger.scope("posthog-client");
 
diff --git a/apps/array/src/renderer/components/ErrorBoundary.tsx b/apps/array/src/renderer/components/ErrorBoundary.tsx
new file mode 100644
index 00000000..2cec73ef
--- /dev/null
+++ b/apps/array/src/renderer/components/ErrorBoundary.tsx
@@ -0,0 +1,56 @@
+import { Button, Card, Flex, Text } from "@radix-ui/themes";
+import { logger } from "@renderer/lib/logger";
+import type { ReactNode } from "react";
+import { ErrorBoundary as ReactErrorBoundary } from "react-error-boundary";
+
+interface Props {
+  children: ReactNode;
+  fallback?: ReactNode;
+}
+
+function DefaultFallback({
+  error,
+  onReset,
+}: {
+  error: Error;
+  onReset: () => void;
+}) {
+  return (
+    <Flex align="center" justify="center" minHeight="100vh" p="4">
+      <Card size="3" style={{ maxWidth: 400 }}>
+        <Flex direction="column" align="center" gap="4" p="4">
+          <Text size="3" weight="bold" align="center">
+            Something went wrong
+          </Text>
+          <Text size="2" color="gray" align="center">
+            {error.message}
+          </Text>
+          <Button onClick={onReset} variant="soft">
+            Try again
+          </Button>
+        </Flex>
+      </Card>
+    </Flex>
+  );
+}
+
+export function ErrorBoundary({ children, fallback }: Props) {
+  return (
+    <ReactErrorBoundary
+      fallbackRender={({ error, resetErrorBoundary }) =>
+        fallback ?? (
+          <DefaultFallback error={error} onReset={resetErrorBoundary} />
+        )
+      }
+      onError={(error, info) => {
+        logger.error("React error boundary caught error", {
+          error: error.message,
+          stack: error.stack,
+          componentStack: info.componentStack,
+        });
+      }}
+    >
+      {children}
+    </ReactErrorBoundary>
+  );
+}
diff --git a/apps/array/src/renderer/features/auth/stores/authStore.ts b/apps/array/src/renderer/features/auth/stores/authStore.ts
index 987167a9..9bb564ac 100644
--- a/apps/array/src/renderer/features/auth/stores/authStore.ts
+++ b/apps/array/src/renderer/features/auth/stores/authStore.ts
@@ -1,4 +1,4 @@
-import { PostHogAPIClient } from "@api/posthogClient";
+import { PostHogAPIClient } from "@renderer/api/posthogClient";
 import { identifyUser, resetUser, track } from "@renderer/lib/analytics";
 import { electronStorage } from "@renderer/lib/electronStorage";
 import { logger } from "@renderer/lib/logger";
diff --git a/apps/array/src/renderer/hooks/useAuthenticatedMutation.ts b/apps/array/src/renderer/hooks/useAuthenticatedMutation.ts
index cfa84518..8a96b90c 100644
--- a/apps/array/src/renderer/hooks/useAuthenticatedMutation.ts
+++ b/apps/array/src/renderer/hooks/useAuthenticatedMutation.ts
@@ -1,5 +1,5 @@
-import type { PostHogAPIClient } from "@api/posthogClient";
 import { useAuthStore } from "@features/auth/stores/authStore";
+import type { PostHogAPIClient } from "@renderer/api/posthogClient";
 import type {
   UseMutationOptions,
   UseMutationResult,
diff --git a/apps/array/src/renderer/hooks/useAuthenticatedQuery.ts b/apps/array/src/renderer/hooks/useAuthenticatedQuery.ts
index c12cc7c2..8ea15774 100644
--- a/apps/array/src/renderer/hooks/useAuthenticatedQuery.ts
+++ b/apps/array/src/renderer/hooks/useAuthenticatedQuery.ts
@@ -1,5 +1,5 @@
-import type { PostHogAPIClient } from "@api/posthogClient";
 import { useAuthStore } from "@features/auth/stores/authStore";
+import type { PostHogAPIClient } from "@renderer/api/posthogClient";
 import type {
   QueryKey,
   UseQueryOptions,
diff --git a/apps/array/src/renderer/hooks/useUserNotifications.ts b/apps/array/src/renderer/hooks/useUserNotifications.ts
new file mode 100644
index 00000000..0482b762
--- /dev/null
+++ b/apps/array/src/renderer/hooks/useUserNotifications.ts
@@ -0,0 +1,20 @@
+import { trpcReact } from "@renderer/trpc/client";
+import { toast } from "@utils/toast";
+
+export function useUserNotifications() {
+  trpcReact.userNotification.onNotify.useSubscription(undefined, {
+    onData: ({ severity, title, description }) => {
+      switch (severity) {
+        case "error":
+          toast.error(title, { description });
+          break;
+        case "warning":
+          toast.warning(title, { description });
+          break;
+        case "info":
+          toast.info(title, description);
+          break;
+      }
+    },
+  });
+}
diff --git a/apps/array/src/renderer/lib/error-handling.ts b/apps/array/src/renderer/lib/error-handling.ts
new file mode 100644
index 00000000..ec135ba9
--- /dev/null
+++ b/apps/array/src/renderer/lib/error-handling.ts
@@ -0,0 +1,50 @@
+import { formatArgsToString } from "@shared/utils/format";
+import { toast } from "@utils/toast";
+import { IS_DEV } from "@/constants/environment";
+import { logger } from "./logger";
+
+const devErrorToastsEnabled =
+  IS_DEV && import.meta.env.VITE_DEV_ERROR_TOASTS !== "false";
+
+export function initializeRendererErrorHandling(): void {
+  if (devErrorToastsEnabled) {
+    interceptConsole();
+  }
+
+  window.addEventListener("error", (event) => {
+    const message = event.error?.message || event.message || "Unknown error";
+    logger.error("Uncaught error", event.error || message);
+    if (!devErrorToastsEnabled) {
+      toast.error("An unexpected error occurred", { description: message });
+    }
+  });
+
+  window.addEventListener("unhandledrejection", (event) => {
+    const message =
+      event.reason instanceof Error
+        ? event.reason.message
+        : String(event.reason || "Unknown error");
+    logger.error("Unhandled rejection", event.reason);
+    if (!devErrorToastsEnabled) {
+      toast.error("An unexpected error occurred", { description: message });
+    }
+  });
+}
+
+function interceptConsole(): void {
+  const { error: originalError, warn: originalWarn } = console;
+
+  console.error = (...args: unknown[]) => {
+    originalError.apply(console, args);
+    toast.error("[DEV] Console error", {
+      description: formatArgsToString(args),
+    });
+  };
+
+  console.warn = (...args: unknown[]) => {
+    originalWarn.apply(console, args);
+    toast.warning("[DEV] Console warning", {
+      description: formatArgsToString(args),
+    });
+  };
+}
diff --git a/apps/array/src/renderer/lib/logger.ts b/apps/array/src/renderer/lib/logger.ts
index 3f7ad109..6023cb16 100644
--- a/apps/array/src/renderer/lib/logger.ts
+++ b/apps/array/src/renderer/lib/logger.ts
@@ -1,28 +1,17 @@
+import type { Logger, ScopedLogger } from "@shared/lib/create-logger";
+import { createLogger } from "@shared/lib/create-logger";
+import { toast } from "@utils/toast";
 import log from "electron-log/renderer";
+import { IS_DEV } from "@/constants/environment";
 
-// Ensure logs appear in dev tools console
 log.transports.console.level = "debug";
 
-export const logger = {
-  info: (message: string, ...args: unknown[]) => log.info(message, ...args),
-  warn: (message: string, ...args: unknown[]) => log.warn(message, ...args),
-  error: (message: string, ...args: unknown[]) => log.error(message, ...args),
-  debug: (message: string, ...args: unknown[]) => log.debug(message, ...args),
+const devErrorToastsEnabled =
+  IS_DEV && import.meta.env.VITE_DEV_ERROR_TOASTS !== "false";
 
-  scope: (name: string) => {
-    const scoped = log.scope(name);
-    return {
-      info: (message: string, ...args: unknown[]) =>
-        scoped.info(message, ...args),
-      warn: (message: string, ...args: unknown[]) =>
-        scoped.warn(message, ...args),
-      error: (message: string, ...args: unknown[]) =>
-        scoped.error(message, ...args),
-      debug: (message: string, ...args: unknown[]) =>
-        scoped.debug(message, ...args),
-    };
-  },
-};
+const emitToast = devErrorToastsEnabled
+  ? (title: string, description?: string) => toast.error(title, { description })
+  : undefined;
 
-export type Logger = typeof logger;
-export type ScopedLogger = ReturnType<typeof logger.scope>;
+export const logger = createLogger(log, emitToast);
+export type { Logger, ScopedLogger };
diff --git a/apps/array/src/renderer/lib/queryClient.ts b/apps/array/src/renderer/lib/queryClient.ts
index 07d7f15c..c4179eb9 100644
--- a/apps/array/src/renderer/lib/queryClient.ts
+++ b/apps/array/src/renderer/lib/queryClient.ts
@@ -1,6 +1,14 @@
-import { QueryClient } from "@tanstack/react-query";
+import { MutationCache, QueryClient } from "@tanstack/react-query";
+import { toast } from "@utils/toast";
 
 export const queryClient = new QueryClient({
+  mutationCache: new MutationCache({
+    onError: (error) => {
+      const message =
+        error instanceof Error ? error.message : "An error occurred";
+      toast.error("Operation failed", { description: message });
+    },
+  }),
   defaultOptions: {
     queries: {
       staleTime: 1000 * 60 * 5,
diff --git a/apps/array/src/renderer/main.tsx b/apps/array/src/renderer/main.tsx
index e69c147e..dcaa0563 100644
--- a/apps/array/src/renderer/main.tsx
+++ b/apps/array/src/renderer/main.tsx
@@ -2,10 +2,14 @@ import "reflect-metadata";
 import "@radix-ui/themes/styles.css";
 import { Providers } from "@components/Providers";
 import App from "@renderer/App";
+import { initializeRendererErrorHandling } from "@renderer/lib/error-handling";
 import React from "react";
 import ReactDOM from "react-dom/client";
 import "./styles/globals.css";
 
+// Initialize error handling early, before React renders
+initializeRendererErrorHandling();
+
 document.title = import.meta.env.DEV ? "Array (Development)" : "Array";
 
 const rootElement = document.getElementById("root");
diff --git a/apps/array/src/renderer/sagas/task/task-creation.ts b/apps/array/src/renderer/sagas/task/task-creation.ts
index dff3e1bc..c9198242 100644
--- a/apps/array/src/renderer/sagas/task/task-creation.ts
+++ b/apps/array/src/renderer/sagas/task/task-creation.ts
@@ -1,7 +1,7 @@
-import type { PostHogAPIClient } from "@api/posthogClient";
 import { buildPromptBlocks } from "@features/editor/utils/prompt-builder";
 import { getSessionActions } from "@features/sessions/stores/sessionStore";
 import { useWorkspaceStore } from "@features/workspace/stores/workspaceStore";
+import type { PostHogAPIClient } from "@renderer/api/posthogClient";
 import { logger } from "@renderer/lib/logger";
 import { useTaskDirectoryStore } from "@renderer/stores/taskDirectoryStore";
 import { trpcVanilla } from "@renderer/trpc";
diff --git a/apps/array/src/renderer/types/electron.d.ts b/apps/array/src/renderer/types/electron.d.ts
index 322a3631..c1b3ad48 100644
--- a/apps/array/src/renderer/types/electron.d.ts
+++ b/apps/array/src/renderer/types/electron.d.ts
@@ -1,3 +1 @@
 import "@main/services/types";
-
-// No legacy IPC interfaces - all communication now uses tRPC
diff --git a/apps/array/src/renderer/utils/toast.tsx b/apps/array/src/renderer/utils/toast.tsx
index d869c605..6be17067 100644
--- a/apps/array/src/renderer/utils/toast.tsx
+++ b/apps/array/src/renderer/utils/toast.tsx
@@ -1,16 +1,88 @@
-import { CheckIcon, InfoIcon, WarningIcon, XIcon } from "@phosphor-icons/react";
-import { Card, Flex, Spinner, Text } from "@radix-ui/themes";
+import {
+  CheckIcon,
+  Copy,
+  InfoIcon,
+  WarningIcon,
+  X,
+  XIcon,
+} from "@phosphor-icons/react";
+import {
+  Box,
+  Button,
+  Card,
+  Dialog,
+  Flex,
+  IconButton,
+  Inset,
+  Spinner,
+  Text,
+  Tooltip,
+} from "@radix-ui/themes";
+
+import { useMemo, useState } from "react";
 import { toast as sonnerToast } from "sonner";
 
+function formatErrorDescription(description: string): {
+  summary: string;
+  details: string;
+  isStructured: boolean;
+} {
+  if (!description) {
+    return { summary: "", details: "", isStructured: false };
+  }
+
+  const trimmed = description.trim();
+  if (!trimmed) {
+    return { summary: "", details: "", isStructured: false };
+  }
+
+  const tryParse = (input: string): unknown | null => {
+    try {
+      return JSON.parse(input);
+    } catch {
+      return null;
+    }
+  };
+
+  const parsedDirect = tryParse(trimmed);
+  if (parsedDirect !== null) {
+    const pretty = JSON.stringify(parsedDirect, null, 2);
+    return { summary: pretty, details: pretty, isStructured: true };
+  }
+
+  const unwrapped =
+    trimmed.startsWith("(") && trimmed.endsWith(")")
+      ? trimmed.slice(1, -1).trim()
+      : trimmed;
+
+  const parsedUnwrapped = tryParse(unwrapped);
+  if (parsedUnwrapped !== null) {
+    const pretty = JSON.stringify(parsedUnwrapped, null, 2);
+    return { summary: pretty, details: pretty, isStructured: true };
+  }
+
+  const asIs = description.replace(/\r\n/g, "\n");
+  return { summary: asIs, details: asIs, isStructured: false };
+}
+
 interface ToastProps {
-  id: string | number;
   type: "loading" | "success" | "error" | "info" | "warning";
   title: string;
   description?: string;
+  dismissable?: boolean;
 }
 
 function ToastComponent(props: ToastProps) {
-  const { type, title, description } = props;
+  const { type, title, description, dismissable = false } = props;
+  const [detailsOpen, setDetailsOpen] = useState(false);
+
+  const formattedDescription = useMemo(() => {
+    if (!description) {
+      return null;
+    }
+
+    return formatErrorDescription(description);
+  }, [description]);
 
   const getIcon = () => {
     switch (type) {
@@ -28,26 +100,147 @@ function ToastComponent(props: ToastProps) {
   };
 
   return (
-    <Card size="2">
-      <Flex gap="3" align="start">
-        <Flex
-          style={{
-            paddingTop: "2px",
-            flexShrink: 0,
-          }}
-        >
-          {getIcon()}
-        </Flex>
-        <Flex direction="column" gap="1" style={{ flex: 1, minWidth: 0 }}>
-          <Text size="1" weight="medium">
-            {title}
-          </Text>
-          {description && (
-            <Text size="1" color="gray" style={{ wordBreak: "break-word" }}>
-              {description}
+    <Card size="1">
+      <Flex direction="column" gap="1">
+        <Flex gap="3" align="center">
+          <Flex
+            style={{
+              paddingTop: "2px",
+              flexShrink: 0,
+            }}
+          >
+            {getIcon()}
+          </Flex>
+          <Flex style={{ flex: 1, minWidth: 0 }}>
+            <Text size="1" weight="medium">
+              {title}
             </Text>
+          </Flex>
+          {dismissable && (
+            <button
+              type="button"
+              onClick={() => {
+                sonnerToast.dismiss();
+              }}
+              style={{
+                flexShrink: 0,
+                marginTop: "-2px",
+                marginRight: "-4px",
+                background: "transparent",
+                border: "none",
+                cursor: "pointer",
+                padding: "4px",
+                borderRadius: "4px",
+                display: "flex",
+                alignItems: "center",
+                justifyContent: "center",
+                color: "var(--gray-11)",
+              }}
+            >
+              <X size={14} />
+            </button>
           )}
         </Flex>
+
+        {formattedDescription && (
+          <Inset
+            px={"current"}
+            pt="current"
+            clip="border-box"
+            side="bottom"
+            pb="current"
+          >
+            <Flex direction="column" gap="1">
+              {formattedDescription.isStructured ||
+              type === "error" ||
+              type === "warning" ? (
+                <Box
+                  style={{
+                    background: "var(--gray-4)",
+                    border: "1px solid var(--gray-6)",
+                    borderRadius: "var(--radius-2)",
+                    padding: "6px",
+                    overflow: "auto",
+                    maxHeight: "120px",
+                  }}
+                >
+                  <Box
+                    style={{
+                      margin: 0,
+                      whiteSpace: "pre-wrap",
+                      overflowWrap: "anywhere",
+                      fontSize: "var(--font-size-1)",
+                      lineHeight: "var(--line-height-1)",
+                      color: "var(--gray-11)",
+                      fontFamily: "var(--font-family-mono)",
+                    }}
+                  >
+                    {formattedDescription.summary}
+                  </Box>
+                </Box>
+              ) : (
+                <Text size="1" color="gray" style={{ wordBreak: "break-word" }}>
+                  {formattedDescription.summary}
+                </Text>
+              )}
+
+              {(type === "error" || type === "warning") && (
+                <Dialog.Root open={detailsOpen} onOpenChange={setDetailsOpen}>
+                  <Dialog.Trigger>
+                    <Button size="1" variant="soft" color="gray">
+                      View details
+                    </Button>
+                  </Dialog.Trigger>
+                  <Dialog.Content maxWidth="720px" size="1">
+                    <Dialog.Description size="1" color="gray">
+                      Full details
+                    </Dialog.Description>
+                    <Flex justify="between" align="center" gap="2">
+                      <Dialog.Title size="1">{title}</Dialog.Title>
+                      <Tooltip content="Copy">
+                        <IconButton
+                          size="1"
+                          variant="ghost"
+                          color="gray"
+                          onClick={async () => {
+                            const toCopy = `${title}\n\n${formattedDescription.details}`;
+                            await navigator.clipboard.writeText(toCopy);
+                            toast.success("Copied to clipboard");
+                          }}
+                        >
+                          <Copy size={14} />
+                        </IconButton>
+                      </Tooltip>
+                    </Flex>
+                    <Box
+                      mt="1"
+                      style={{
+                        background: "var(--gray-3)",
+                        border: "1px solid var(--gray-6)",
+                        borderRadius: "var(--radius-3)",
+                        padding: "8px",
+                        overflow: "auto",
+                        maxHeight: "60vh",
+                      }}
+                    >
+                      <Box
+                        style={{
+                          margin: 0,
+                          whiteSpace: "pre-wrap",
+                          fontSize: "var(--font-size-1)",
+                          lineHeight: "var(--line-height-1)",
+                          fontFamily: "var(--font-family-mono)",
+                        }}
+                      >
+                        {formattedDescription.details}
+                      </Box>
+                    </Box>
+                  </Dialog.Content>
+                </Dialog.Root>
+              )}
+            </Flex>
+          </Inset>
+        )}
       </Flex>
     </Card>
   );
@@ -55,13 +248,8 @@ function ToastComponent(props: ToastProps) {
 
 export const toast = {
   loading: (title: string, description?: string) => {
-    return sonnerToast.custom((id) => (
-      <ToastComponent
-        id={id}
-        type="loading"
-        title={title}
-        description={description}
-      />
+    return sonnerToast.custom(() => (
+      <ToastComponent type="loading" title={title} description={description} />
     ));
   },
 
@@ -70,12 +258,12 @@ export const toast = {
     options?: { description?: string; id?: string | number },
   ) => {
     return sonnerToast.custom(
-      (id) => (
+      () => (
         <ToastComponent
-          id={id}
           type="success"
           title={title}
           description={options?.description}
+          dismissable
         />
       ),
       { id: options?.id },
@@ -87,25 +275,25 @@ export const toast = {
     options?: { description?: string; id?: string | number },
   ) => {
     return sonnerToast.custom(
-      (id) => (
+      () => (
         <ToastComponent
-          id={id}
           type="error"
           title={title}
           description={options?.description}
+          dismissable
         />
       ),
-      { id: options?.id },
+      { id: options?.id, duration: Number.POSITIVE_INFINITY },
     );
   },
 
   info: (title: string, description?: string) => {
-    return sonnerToast.custom((id) => (
+    return sonnerToast.custom(() => (
       <ToastComponent
-        id={id}
         type="info"
         title={title}
         description={description}
+        dismissable
       />
     ));
   },
@@ -115,15 +303,18 @@ export const toast = {
     options?: { description?: string; id?: string | number; duration?: number },
   ) => {
     return sonnerToast.custom(
-      (id) => (
+      () => (
         <ToastComponent
-          id={id}
           type="warning"
           title={title}
           description={options?.description}
+          dismissable
         />
       ),
-      { id: options?.id, duration: options?.duration },
+      {
+        id: options?.id,
+        duration: options?.duration ?? Number.POSITIVE_INFINITY,
+      },
     );
   },
 };
diff --git a/apps/array/src/shared/lib/create-logger.ts b/apps/array/src/shared/lib/create-logger.ts
new file mode 100644
index 00000000..73de8ccd
--- /dev/null
+++ b/apps/array/src/shared/lib/create-logger.ts
@@ -0,0 +1,66 @@
+import { formatErrorDescription } from "@shared/utils/format";
+
+type LogFn = (message: string, ...args: unknown[]) => void;
+
+interface BaseLog {
+  info: LogFn;
+  warn: LogFn;
+  error: LogFn;
+  debug: LogFn;
+  scope: (name: string) => {
+    info: LogFn;
+    warn: LogFn;
+    error: LogFn;
+    debug: LogFn;
+  };
+}
+
+export interface ScopedLogger {
+  info: LogFn;
+  warn: LogFn;
+  error: LogFn;
+  debug: LogFn;
+  scope: (name: string) => ScopedLogger;
+}
+
+export interface Logger extends ScopedLogger {
+  setDevToastEmitter: (emitter: DevToastEmitter | undefined) => void;
+}
+
+export type DevToastEmitter = (title: string, description?: string) => void;
+
+export function createLogger(
+  log: BaseLog,
+  initialEmitter?: DevToastEmitter,
+): Logger {
+  let emitToast = initialEmitter;
+
+  const createScopedLogger = (
+    scoped: { info: LogFn; warn: LogFn; error: LogFn; debug: LogFn },
+    name: string,
+  ): ScopedLogger => ({
+    info: scoped.info,
+    warn: scoped.warn,
+    debug: scoped.debug,
+    error: (message, ...args) => {
+      scoped.error(message, ...args);
+      emitToast?.(`[DEV] [${name}] ${message}`, formatErrorDescription(args));
+    },
+    scope: (subName) =>
+      createScopedLogger(log.scope(`${name}:${subName}`), `${name}:${subName}`),
+  });
+
+  return {
+    info: log.info,
+    warn: log.warn,
+    debug: log.debug,
+    error: (message, ...args) => {
+      log.error(message, ...args);
+      emitToast?.(`[DEV] ${message}`, formatErrorDescription(args));
+    },
+    scope: (name) => createScopedLogger(log.scope(name), name),
+    setDevToastEmitter: (emitter) => {
+      emitToast = emitter;
+    },
+  };
+}
diff --git a/apps/array/src/shared/utils/format.ts b/apps/array/src/shared/utils/format.ts
new file mode 100644
index 00000000..0e3551fc
--- /dev/null
+++ b/apps/array/src/shared/utils/format.ts
@@ -0,0 +1,70 @@
+/**
+ * Formats an array of arguments into a string description of the error.
+ * @param args - The arguments to format.
+ * @returns The formatted string description of the error.
+ */
+export function formatErrorDescription(args: unknown[]): string | undefined {
+  if (args.length === 0) return undefined;
+  const first = args[0];
+  if (first instanceof Error) return first.message;
+  if (typeof first === "string") return first;
+  if (first !== null && first !== undefined) {
+    try {
+      return JSON.stringify(first);
+    } catch {
+      return String(first);
+    }
+  }
+  return undefined;
+}
+
+function formatConsoleArg(arg: unknown): string {
+  if (arg instanceof Error) {
+    return arg.stack || arg.message;
+  }
+
+  if (typeof arg === "string") {
+    return arg;
+  }
+
+  try {
+    return JSON.stringify(arg);
+  } catch {
+    return String(arg);
+  }
+}
+
+function formatConsoleArgsWithSubstitutions(args: unknown[]): string {
+  if (args.length === 0) {
+    return "";
+  }
+
+  const first = args[0];
+  if (typeof first !== "string") {
+    return args.map(formatConsoleArg).join(" ");
+  }
+
+  let template = first;
+  let nextArgIndex = 1;
+
+  template = template.replace(/%[sdifoO]/g, () => {
+    if (nextArgIndex >= args.length) {
+      return "";
+    }
+
+    const replacement = formatConsoleArg(args[nextArgIndex]);
+    nextArgIndex += 1;
+    return replacement;
+  });
+
+  const rest = args.slice(nextArgIndex).map(formatConsoleArg);
+  return rest.length > 0 ? `${template} ${rest.join(" ")}` : template;
+}
+
+export function formatArgsToString(args: unknown[], maxLength = 5000): string {
+  const formatted = formatConsoleArgsWithSubstitutions(args);
+
+  return formatted.length > maxLength
+    ? `${formatted.slice(0, maxLength)}\n… (truncated)`
+    : formatted;
+}
diff --git a/apps/array/src/vite-env.d.ts b/apps/array/src/vite-env.d.ts
index 41c10685..d8cd056b 100644
--- a/apps/array/src/vite-env.d.ts
+++ b/apps/array/src/vite-env.d.ts
@@ -9,6 +9,7 @@ interface ImportMetaEnv {
   readonly VITE_POSTHOG_API_KEY?: string;
   readonly VITE_POSTHOG_API_HOST?: string;
   readonly VITE_POSTHOG_UI_HOST?: string;
+  readonly VITE_DEV_ERROR_TOASTS?: string;
 }
 
 interface ImportMeta {
diff --git a/apps/array/vite.main.config.mts b/apps/array/vite.main.config.mts
index d14ddf02..104b234f 100644
--- a/apps/array/vite.main.config.mts
+++ b/apps/array/vite.main.config.mts
@@ -19,6 +19,7 @@ function _getBuildDate(): string {
 }
 
 const __dirname = path.dirname(fileURLToPath(import.meta.url));
+const _monorepoRoot = path.resolve(__dirname, "../..");
 
 /**
  * Custom Vite plugin to fix circular __filename references in bundled ESM packages.
diff --git a/apps/array/vite.preload.config.mts b/apps/array/vite.preload.config.mts
index 93f99676..7545698f 100644
--- a/apps/array/vite.preload.config.mts
+++ b/apps/array/vite.preload.config.mts
@@ -5,8 +5,10 @@ import tsconfigPaths from "vite-tsconfig-paths";
 import { autoServicesPlugin } from "./vite-plugin-auto-services.js";
 
 const __dirname = path.dirname(fileURLToPath(import.meta.url));
+const monorepoRoot = path.resolve(__dirname, "../..");
 
 export default defineConfig({
+  envDir: monorepoRoot,
   plugins: [
     tsconfigPaths(),
     autoServicesPlugin(path.join(__dirname, "src/main/services")),
diff --git a/apps/array/vite.renderer.config.mts b/apps/array/vite.renderer.config.mts
index b9b84534..9cbece54 100644
--- a/apps/array/vite.renderer.config.mts
+++ b/apps/array/vite.renderer.config.mts
@@ -5,6 +5,7 @@ import { defineConfig } from "vite";
 import tsconfigPaths from "vite-tsconfig-paths";
 
 const __dirname = path.dirname(fileURLToPath(import.meta.url));
+const _monorepoRoot = path.resolve(__dirname, "../..");
 
 // Allow forcing dev mode in packaged builds via FORCE_DEV_MODE=1
 const forceDevMode = process.env.FORCE_DEV_MODE === "1";
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 7b77b366..96bccccb 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -245,6 +245,9 @@ importers:
       react-dom:
         specifier: ^18.2.0
         version: 18.3.1(react@18.3.1)
+      react-error-boundary:
+        specifier: ^6.0.0
+        version: 6.0.0(react@18.3.1)
       react-hook-form:
         specifier: ^7.64.0
         version: 7.66.1(react@18.3.1)
@@ -6312,6 +6315,11 @@ packages:
     peerDependencies:
       react: ^18.3.1
 
+  react-error-boundary@6.0.0:
+    resolution: {integrity: sha512-gdlJjD7NWr0IfkPlaREN2d9uUZUlksrfOx7SX62VRerwXbMY6ftGCIZua1VG1aXFNOimhISsTq+Owp725b9SiA==}
+    peerDependencies:
+      react: '>=16.13.1'
+
   react-hook-form@7.66.1:
     resolution: {integrity: sha512-2KnjpgG2Rhbi+CIiIBQQ9Df6sMGH5ExNyFl4Hw9qO7pIqMBR8Bvu9RQyjl3JM4vehzCh9soiNUM/xYMswb2EiA==}
     engines: {node: '>=18.0.0'}
@@ -14369,6 +14377,11 @@ snapshots:
       react: 18.3.1
       scheduler: 0.23.2
 
+  react-error-boundary@6.0.0(react@18.3.1):
+    dependencies:
+      '@babel/runtime': 7.28.4
+      react: 18.3.1
+
   react-hook-form@7.66.1(react@18.3.1):
     dependencies:
       react: 18.3.1