feat(desktop): gate sources panel add-source button on launch flag

packages/desktop/apps/electron/src/preload/bootstrap.ts

@@ -23,6 +23,7 @@ import { RoutedClient } from '../transport/routed-client'
 import { buildClientApi } from '../transport/build-api'
 import { CHANNEL_MAP } from '../transport/channel-map'
 import { createCallbackServer } from '@craft-agent/shared/auth/callback-server'
+import { isAddSourceButtonEnabled } from '@craft-agent/shared/feature-flags'
 import {
   CLIENT_OPEN_EXTERNAL,
   CLIENT_OPEN_PATH,
@@ -187,6 +188,7 @@ client.handleCapability(CLIENT_OPEN_FILE_DIALOG, async (spec: FileDialogSpec) =>
 const api = buildClientApi(client, CHANNEL_MAP, (ch) => client.isChannelAvailable(ch))
 
 ;(api as any).getRuntimeEnvironment = (): 'electron' | 'web' => 'electron'
+;(api as any).isAddSourceButtonEnabled = (): boolean => isAddSourceButtonEnabled()
 
 // ---------------------------------------------------------------------------
 // Transport connection state logging (for remote connections)

packages/desktop/apps/electron/src/renderer/components/app-shell/AppShell.tsx

@@ -4970,8 +4970,8 @@ function AppShellContent({
                           </StyledDropdownMenuContent>
                         </DropdownMenu>
                       )}
-                      {/* Add Source button (only for sources mode) - uses filter-aware edit config */}
-                      {isSourcesNavigation(navState) && activeWorkspace && (
+                      {/* Add Source button (only for sources mode) - uses filter-aware edit config. Hidden unless enabled via launch flag. */}
+                      {isSourcesNavigation(navState) && activeWorkspace && window.electronAPI.isAddSourceButtonEnabled() && (
                         <EditPopover
                           trigger={
                             <HeaderIconButton

packages/desktop/apps/electron/src/renderer/playground/mock-utils.ts

@@ -141,6 +141,9 @@ export const mockElectronAPI = {
   // branch between Electron and web-UI rendering. Must be synchronous.
   getRuntimeEnvironment: (): 'electron' | 'web' => 'electron',
 
+  // Keep the sources panel "add source" button visible in the playground.
+  isAddSourceButtonEnabled: () => true,
+
   openFileDialog: async () => {
     console.log('[Playground] openFileDialog called')
     return [] // Let user use file input or drag-drop

packages/desktop/apps/electron/src/shared/types.ts

@@ -519,6 +519,8 @@ export interface ElectronAPI {
   getVersions(): { node: string; chrome: string; electron: string };
   /** Returns the renderer host environment without going through RPC. */
   getRuntimeEnvironment(): 'electron' | 'web';
+  /** Whether the sources panel "add source" header button is shown. Preload-local launch flag. */
+  isAddSourceButtonEnabled(): boolean;
   getHomeDir(): Promise<string>;
   isDebugMode(): Promise<boolean>;
 

packages/desktop/apps/electron/src/transport/__tests__/channel-map-parity.test.ts

@@ -17,6 +17,7 @@ type ApiToChannelMapKeys = Exclude<
   | 'performOAuth'
   | 'getTransportConnectionState'
   | 'getRuntimeEnvironment'
+  | 'isAddSourceButtonEnabled' // reads launch env var in the preload — no IPC needed
   | 'onTransportConnectionStateChanged'
   | 'reconnectTransport'
   | 'isChannelAvailable'

packages/desktop/apps/webui/src/adapter/web-api.ts

@@ -109,6 +109,7 @@ export function createWebApi(options: WebApiOptions): {
     // System info
     getVersions: () => ({ node: 'n/a', chrome: navigator.userAgent, electron: 'web' }),
     getRuntimeEnvironment: () => 'web',
+    isAddSourceButtonEnabled: () => false,
     getSystemWarnings: () => Promise.resolve({ vcredistMissing: false }),
     isDebugMode: () => Promise.resolve(import.meta.env.DEV),
 

packages/desktop/packages/shared/src/feature-flags.ts

@@ -59,6 +59,17 @@ export function isEmbeddedServerEnabled(): boolean {
   return false;
 }
 
+/**
+ * Runtime-evaluated check for the sources panel "add source" header button.
+ *
+ * Defaults to disabled. Override with CRAFT_FEATURE_ADD_SOURCE_BUTTON=1|0.
+ */
+export function isAddSourceButtonEnabled(): boolean {
+  const override = parseBooleanEnv(getEnv('CRAFT_FEATURE_ADD_SOURCE_BUTTON'));
+  if (override !== undefined) return override;
+  return false;
+}
+
 export const FEATURE_FLAGS = {
   /** Enable Opus 4.7 fast mode (speed:"fast" + beta header). 6x pricing. */
   fastMode: false,
@@ -89,4 +100,12 @@ export const FEATURE_FLAGS = {
   get embeddedServer(): boolean {
     return isEmbeddedServerEnabled();
   },
+  /**
+   * Show the "add source" button in the sources panel header.
+   *
+   * Defaults to disabled. Override with CRAFT_FEATURE_ADD_SOURCE_BUTTON=1|0.
+   */
+  get addSourceButton(): boolean {
+    return isAddSourceButtonEnabled();
+  },
 } as const;