DX Improvements: Bun support, multi-instance config, and terminal paste fix + Feat: Model selection

apps/desktop/electron/app-store-persistence.ts

@@ -25,6 +25,7 @@ export interface PersistedUiState {
   readonly modelSettingsScopeMode?: ModelSettingsScopeMode;
   readonly appGlobalModelSettings?: ModelSettingsSnapshot;
   readonly sidebarCollapsed?: boolean;
+  readonly allowMultiple?: boolean;
 }
 
 export interface LegacyPersistedUiState extends PersistedUiState {
@@ -71,7 +72,8 @@ export async function readPersistedUiState(uiStateFilePath: string): Promise<Leg
           ? parsed.modelSettingsScopeMode
           : undefined,
       appGlobalModelSettings: toPersistedModelSettingsSnapshot(parsed.appGlobalModelSettings),
-      sidebarCollapsed: parsed.sidebarCollapsed === true,
+      sidebarCollapsed: typeof parsed.sidebarCollapsed === "boolean" ? parsed.sidebarCollapsed : undefined,
+      allowMultiple: typeof parsed.allowMultiple === "boolean" ? parsed.allowMultiple : undefined,
       composerAttachmentsBySession: parsed.composerAttachmentsBySession,
       transcripts: parsed.transcripts,
     };

apps/desktop/electron/app-store.ts

@@ -493,6 +493,21 @@ export class DesktopAppStore implements AppStoreInternals {
     return this.emit();
   }
 
+  async setAllowMultiple(allowMultiple: boolean): Promise<DesktopAppState> {
+    await this.initialize();
+    if (this.state.allowMultiple === allowMultiple) {
+      return this.emit();
+    }
+    this.state = {
+      ...this.state,
+      allowMultiple,
+      lastError: undefined,
+      revision: this.state.revision + 1,
+    };
+    await this.persistUiState();
+    return this.emit();
+  }
+
   async setModelSettingsScopeMode(modelSettingsScopeMode: ModelSettingsScopeMode): Promise<DesktopAppState> {
     await this.initialize();
     if (this.state.modelSettingsScopeMode === modelSettingsScopeMode) {
@@ -731,8 +746,8 @@ export class DesktopAppStore implements AppStoreInternals {
   /* ── Internal infrastructure (AppStoreInternals) ───────── */
 
   private async initializeInternal(): Promise<void> {
+    const persisted = await this.readUiState();
     try {
-      const persisted = await this.readUiState();
       this.state = {
         ...this.state,
         activeView: persisted.activeView ?? this.state.activeView,
@@ -746,6 +761,7 @@ export class DesktopAppStore implements AppStoreInternals {
         lastViewedAtBySession: persisted.lastViewedAtBySession ?? {},
         workspaceOrder: persisted.workspaceOrder ?? [],
         sidebarCollapsed: persisted.sidebarCollapsed ?? this.state.sidebarCollapsed,
+        allowMultiple: persisted.allowMultiple ?? this.state.allowMultiple,
       };
       await this.migrateLegacyPersistence(persisted);
       this.sessionState.lastViewedAtBySession.clear();
@@ -796,6 +812,7 @@ export class DesktopAppStore implements AppStoreInternals {
     } catch (error) {
       this.state = {
         ...createEmptyDesktopAppState(),
+        allowMultiple: persisted.allowMultiple ?? false,
         lastError: error instanceof Error ? error.message : String(error),
         revision: 1,
       };
@@ -1689,6 +1706,7 @@ export class DesktopAppStore implements AppStoreInternals {
       modelSettingsScopeMode: this.state.modelSettingsScopeMode,
       appGlobalModelSettings: hasStoredModelSettings(this.state.globalModelSettings) ? this.state.globalModelSettings : undefined,
       sidebarCollapsed: this.state.sidebarCollapsed || undefined,
+      allowMultiple: this.state.allowMultiple,
     };
 
     await writePersistedUiState(this.uiStateFilePath, payload);

apps/desktop/electron/main.ts

@@ -12,6 +12,7 @@ import {
 } from "electron";
 import { randomUUID } from "node:crypto";
 import { readFile, stat } from "node:fs/promises";
+import { readFileSync } from "node:fs";
 import path from "node:path";
 import { pathToFileURL } from "node:url";
 import { DesktopAppStore } from "./app-store";
@@ -378,12 +379,26 @@ app.setName("pi");
 const configuredUserDataDir = process.env.PI_APP_USER_DATA_DIR?.trim() || app.getPath("userData");
 app.setPath("userData", configuredUserDataDir);
 
-const hasSingleInstanceLock = app.requestSingleInstanceLock();
+function getPersistedAllowMultiple(): boolean {
+  if (process.env.PI_APP_ALLOW_MULTIPLE === "1") {
+    return true;
+  }
+  try {
+    const uiStatePath = path.join(configuredUserDataDir, "ui-state.json");
+    const raw = readFileSync(uiStatePath, "utf8");
+    const parsed = JSON.parse(raw);
+    return typeof parsed.allowMultiple === "boolean" ? parsed.allowMultiple : false;
+  } catch {
+    return false;
+  }
+}
+
+const hasSingleInstanceLock = getPersistedAllowMultiple() || app.requestSingleInstanceLock();
 if (!hasSingleInstanceLock) {
   app.quit();
 }
 
-app.on("second-instance", () => {
+app.on("second-instance", async () => {
   if (!mainWindow || mainWindow.isDestroyed()) {
     return;
   }
@@ -575,6 +590,9 @@ app.whenReady().then(async () => {
   ipcMain.handle(desktopIpc.setIntegratedTerminalShell, (_event, shellPath: string) =>
     store.setIntegratedTerminalShell(shellPath),
   );
+  ipcMain.handle(desktopIpc.setAllowMultiple, (_event, allowMultiple: boolean) =>
+    store.setAllowMultiple(allowMultiple),
+  );
   ipcMain.handle(desktopIpc.terminalEnsurePanel, (event, workspaceId: string, terminalScopeId: string, size) => {
     return getTerminalService().ensurePanel(event.sender, workspaceId, terminalScopeId, size);
   });

apps/desktop/electron/preload.ts

@@ -182,6 +182,8 @@ contextBridge.exposeInMainWorld("piApp", {
     ipcRenderer.invoke(desktopIpc.setNotificationPreferences, preferences) as Promise<DesktopAppState>,
   setIntegratedTerminalShell: (shellPath: string) =>
     ipcRenderer.invoke(desktopIpc.setIntegratedTerminalShell, shellPath) as Promise<DesktopAppState>,
+  setAllowMultiple: (allowMultiple: boolean) =>
+    ipcRenderer.invoke(desktopIpc.setAllowMultiple, allowMultiple) as Promise<DesktopAppState>,
   ensureTerminalPanel: (workspaceId: string, terminalScopeId: string, size?: Partial<TerminalSize>) =>
     ipcRenderer.invoke(desktopIpc.terminalEnsurePanel, workspaceId, terminalScopeId, size) as Promise<TerminalPanelSnapshot>,
   createTerminalSession: (workspaceId: string, terminalScopeId: string, size?: Partial<TerminalSize>) =>

apps/desktop/package.json

@@ -8,15 +8,22 @@
   "main": "out/main/main.js",
   "scripts": {
     "build:deps": "pnpm --dir ../.. --filter @pi-gui/session-driver --filter @pi-gui/pi-sdk-driver --filter @pi-gui/catalogs run build",
+    "bun:build:deps": "for dir in ../../packages/session-driver ../../packages/pi-sdk-driver ../../packages/catalogs; do (cd \"$dir\" && bun run build); done",
     "build:notification-helper": "node scripts/build-notification-status-helper.mjs",
     "dev": "node scripts/dev.mjs",
     "build": "pnpm run build:deps && pnpm run build:notification-helper && electron-vite build",
+    "bun:build": "bun run bun:build:deps && bun run build:notification-helper && electron-vite build",
     "preview": "pnpm run build:deps && pnpm run build:notification-helper && electron-vite preview",
+    "bun:preview": "bun run bun:build:deps && bun run build:notification-helper && electron-vite preview",
     "start": "pnpm run preview",
     "package": "pnpm run build && electron-builder --mac",
+    "bun:package": "bun run bun:build && bun run scripts/bun-package-wrapper.mjs electron-builder --mac",
     "package:dir": "pnpm run build && electron-builder --mac --dir",
+    "bun:package:dir": "bun run bun:build && bun run scripts/bun-package-wrapper.mjs electron-builder --mac --dir",
     "package:linux": "pnpm run build && electron-builder --linux AppImage",
+    "bun:package:linux": "bun run bun:build && bun run scripts/bun-package-wrapper.mjs electron-builder --linux AppImage",
     "package:linux:dir": "pnpm run build && electron-builder --linux --dir",
+    "bun:package:linux:dir": "bun run bun:build && bun run scripts/bun-package-wrapper.mjs electron-builder --linux --dir",
     "typecheck": "tsc -p tsconfig.json --noEmit && tsc -p tsconfig.electron.json --noEmit",
     "verify:runtime-model-registry": "node scripts/assert-runtime-model-registry.mjs",
     "verify:packaged-runtime-deps": "pnpm run verify:runtime-model-registry && node scripts/assert-packaged-runtime-deps.mjs",
@@ -118,4 +125,4 @@
     "vite": "^6.2.0",
     "vite-tsconfig-paths": "^6.1.1"
   }
-}
+}

apps/desktop/scripts/bun-package-wrapper.mjs

@@ -0,0 +1,36 @@
+import { spawnSync } from "node:child_process";
+import { readFileSync, writeFileSync } from "node:fs";
+import path from "node:path";
+
+const ROOT_PACKAGE_JSON = path.resolve(process.cwd(), "../../package.json");
+const originalContent = readFileSync(ROOT_PACKAGE_JSON, "utf8");
+const json = JSON.parse(originalContent);
+const [command, ...args] = process.argv.slice(2);
+
+if (!command) {
+  throw new Error("Usage: bun-package-wrapper.mjs <command> [...args]");
+}
+
+const originalPM = json.packageManager;
+json.packageManager = "bun";
+
+writeFileSync(ROOT_PACKAGE_JSON, JSON.stringify(json, null, 2));
+
+console.log(`Temporarily set packageManager to bun (was ${originalPM})`);
+
+let exitCode = 0;
+try {
+  const result = spawnSync(command, args, {
+    stdio: "inherit",
+    env: { ...process.env, npm_config_user_agent: "bun" },
+  });
+  if (result.error) {
+    throw result.error;
+  }
+  exitCode = result.status ?? (result.signal ? 1 : 0);
+} finally {
+  writeFileSync(ROOT_PACKAGE_JSON, originalContent);
+  console.log(`Restored packageManager to ${originalPM}`);
+}
+
+process.exit(exitCode);

apps/desktop/scripts/dev.mjs

@@ -7,8 +7,19 @@ const desktopDir = path.resolve(__dirname, "..");
 const repoRoot = path.resolve(desktopDir, "..", "..");
 const rawArgs = process.argv.slice(2);
 const extraArgs = rawArgs[0] === "--" ? rawArgs.slice(1) : rawArgs;
+
+// pnpm uses package filters to identify workspace packages
 const packageFilters = ["@pi-gui/session-driver", "@pi-gui/pi-sdk-driver", "@pi-gui/catalogs"];
 
+// Bun handles these manually by directory
+const packagePaths = [
+  path.resolve(repoRoot, "packages/session-driver"),
+  path.resolve(repoRoot, "packages/pi-sdk-driver"),
+  path.resolve(repoRoot, "packages/catalogs"),
+];
+
+const isBun = process.versions.bun || process.env.npm_config_user_agent?.includes("bun");
+
 async function run(cmd, args, cwd) {
   await new Promise((resolve, reject) => {
     const child = spawn(cmd, args, {
@@ -38,33 +49,46 @@ function start(cmd, args, cwd) {
 }
 
 async function main() {
-  await run(
-    "pnpm",
-    ["--dir", repoRoot, "--filter", packageFilters[0], "--filter", packageFilters[1], "--filter", packageFilters[2], "run", "build"],
-    desktopDir,
-  );
-
-  const children = [
-    start(
+  if (isBun) {
+    for (const pkgPath of packagePaths) {
+      await run("bun", ["run", "build"], pkgPath);
+    }
+  } else {
+    await run(
       "pnpm",
-      [
-        "--dir",
-        repoRoot,
-        "--parallel",
-        "--filter",
-        packageFilters[0],
-        "--filter",
-        packageFilters[1],
-        "--filter",
-        packageFilters[2],
-        "run",
-        "build",
-        "--watch",
-      ],
+      ["--dir", repoRoot, "--filter", packageFilters[0], "--filter", packageFilters[1], "--filter", packageFilters[2], "run", "build"],
       desktopDir,
-    ),
-    start("pnpm", ["exec", "electron-vite", "dev", "--watch", ...extraArgs], desktopDir),
-  ];
+    );
+  }
+
+  const children = isBun
+    ? [
+        ...packagePaths.map((pkgPath) =>
+          start("bun", ["x", "tsc", "-w", "-p", "tsconfig.json"], pkgPath),
+        ),
+        start("bun", ["x", "electron-vite", "dev", "--watch", ...extraArgs], desktopDir),
+      ]
+    : [
+        start(
+          "pnpm",
+          [
+            "--dir",
+            repoRoot,
+            "--parallel",
+            "--filter",
+            packageFilters[0],
+            "--filter",
+            packageFilters[1],
+            "--filter",
+            packageFilters[2],
+            "run",
+            "build",
+            "--watch",
+          ],
+          desktopDir,
+        ),
+        start("pnpm", ["exec", "electron-vite", "dev", "--watch", ...extraArgs], desktopDir),
+      ];
 
   let exiting = false;
   const stopChildren = () => {
@@ -104,4 +128,4 @@ async function main() {
 main().catch((error) => {
   console.error(error);
   process.exit(1);
-});
+});

apps/desktop/src/App.tsx

@@ -1668,6 +1668,10 @@ export default function App() {
     void updateSnapshot(api, setSnapshot, () => api.setIntegratedTerminalShell(shellPath));
   };
 
+  const handleToggleAllowMultiple = (enabled: boolean) => {
+    void updateSnapshot(api, setSnapshot, () => api.setAllowMultiple(enabled));
+  };
+
   const handleRequestNotificationPermission = () => {
     if (!api?.requestNotificationPermission) {
       return;
@@ -1911,6 +1915,7 @@ export default function App() {
           notificationPermissionPending={notificationPermissionPending}
           modelSettingsScopeMode={snapshot.modelSettingsScopeMode}
           integratedTerminalShell={snapshot.integratedTerminalShell}
+          allowMultiple={snapshot.allowMultiple}
           themeMode={themeMode}
           onLoginProvider={handleLoginProvider}
           onLogoutProvider={handleLogoutProvider}
@@ -1920,6 +1925,7 @@ export default function App() {
           onSetDefaultModel={handleSetDefaultModel}
           onSetNotificationPreferences={handleSetNotificationPreferences}
           onSetIntegratedTerminalShell={handleSetIntegratedTerminalShell}
+          onToggleAllowMultiple={handleToggleAllowMultiple}
           onRequestNotificationPermission={handleRequestNotificationPermission}
           onOpenSystemNotificationSettings={handleOpenSystemNotificationSettings}
           onSetScopedModelPatterns={handleSetScopedModelPatterns}

apps/desktop/src/desktop-state.ts

@@ -169,6 +169,7 @@ export interface DesktopAppState {
   readonly extensionCommandCompatibilityByWorkspace: Readonly<Record<string, readonly ExtensionCommandCompatibilityRecord[]>>;
   readonly notificationPreferences: NotificationPreferences;
   readonly integratedTerminalShell: string;
+  readonly allowMultiple: boolean;
   readonly lastViewedAtBySession: Readonly<Record<string, string>>;
   readonly workspaceOrder: readonly string[];
   readonly modelSettingsScopeMode: ModelSettingsScopeMode;
@@ -210,6 +211,7 @@ export function createEmptyDesktopAppState(): DesktopAppState {
       attentionNeeded: true,
     },
     integratedTerminalShell: "",
+    allowMultiple: false,
     lastViewedAtBySession: {},
     workspaceOrder: [],
     modelSettingsScopeMode: "app-global",

apps/desktop/src/ipc.ts

@@ -70,6 +70,7 @@ export const desktopIpc = {
   respondToHostUiRequest: "pi-gui:respond-to-host-ui-request",
   setNotificationPreferences: "pi-gui:set-notification-preferences",
   setIntegratedTerminalShell: "pi-gui:set-integrated-terminal-shell",
+  setAllowMultiple: "pi-gui:set-allow-multiple",
   terminalEnsurePanel: "pi-gui:terminal-ensure-panel",
   terminalCreateSession: "pi-gui:terminal-create-session",
   terminalSetActiveSession: "pi-gui:terminal-set-active-session",
@@ -273,6 +274,7 @@ export interface PiDesktopApi {
   ): Promise<DesktopAppState>;
   setNotificationPreferences(preferences: Partial<NotificationPreferences>): Promise<DesktopAppState>;
   setIntegratedTerminalShell(shell: string): Promise<DesktopAppState>;
+  setAllowMultiple(allowMultiple: boolean): Promise<DesktopAppState>;
   ensureTerminalPanel(
     workspaceId: string,
     terminalScopeId: string,