Signed-off-by: Matt Bruce <mbrucedogs@gmail.com>

Agents.md

@@ -604,6 +604,88 @@ FileManager.default.containerURL(
 CKContainer(identifier: AppIdentifiers.cloudKitContainerIdentifier)
 ```
 
+### Adding New Targets
+
+When adding new targets (Widgets, Intents, App Clips, etc.), follow this pattern:
+
+#### 1. Add Bundle ID Variable to Base.xcconfig
+
+```
+// In Base.xcconfig, add new derived identifier
+WIDGET_BUNDLE_IDENTIFIER = $(APP_BUNDLE_IDENTIFIER).Widget
+INTENT_BUNDLE_IDENTIFIER = $(APP_BUNDLE_IDENTIFIER).Intent
+```
+
+#### 2. Set Target to Use xcconfig
+
+For the new target's Debug/Release configurations in `project.pbxproj`:
+
+```
+EA_NEW_TARGET_DEBUG /* Debug */ = {
+    isa = XCBuildConfiguration;
+    baseConfigurationReference = EACONFIG002 /* Debug.xcconfig */;
+    buildSettings = {
+        PRODUCT_BUNDLE_IDENTIFIER = "$(WIDGET_BUNDLE_IDENTIFIER)";
+        DEVELOPMENT_TEAM = "$(DEVELOPMENT_TEAM)";
+        // ... other settings
+    };
+};
+```
+
+#### 3. Configure Entitlements (if needed)
+
+If the target needs App Groups or CloudKit access, create an entitlements file using variables:
+
+```xml
+<!-- WidgetExtension.entitlements -->
+<key>com.apple.security.application-groups</key>
+<array>
+    <string>$(APP_GROUP_IDENTIFIER)</string>
+</array>
+```
+
+#### 4. Share Code via App Groups
+
+Extensions must use App Groups to share data with the main app:
+
+```swift
+// In extension code
+let sharedDefaults = UserDefaults(suiteName: AppIdentifiers.appGroupIdentifier)
+let containerURL = FileManager.default.containerURL(
+    forSecurityApplicationGroupIdentifier: AppIdentifiers.appGroupIdentifier
+)
+```
+
+#### 5. Update AppIdentifiers.swift (if needed)
+
+Add new computed properties for target-specific identifiers:
+
+```swift
+static var widgetBundleIdentifier: String { "\(bundleIdentifier).Widget" }
+static var intentBundleIdentifier: String { "\(bundleIdentifier).Intent" }
+```
+
+#### Common Target Types and Bundle ID Patterns
+
+| Target Type | Bundle ID Variable | Example Value |
+|-------------|-------------------|---------------|
+| Widget Extension | `WIDGET_BUNDLE_IDENTIFIER` | `$(APP_BUNDLE_IDENTIFIER).Widget` |
+| Intent Extension | `INTENT_BUNDLE_IDENTIFIER` | `$(APP_BUNDLE_IDENTIFIER).Intent` |
+| App Clip | `APPCLIP_BUNDLE_IDENTIFIER` | `$(APP_BUNDLE_IDENTIFIER).Clip` |
+| Watch App | `WATCH_BUNDLE_IDENTIFIER` | `$(APP_BUNDLE_IDENTIFIER).watchkitapp` |
+| Notification Extension | `NOTIFICATION_BUNDLE_IDENTIFIER` | `$(APP_BUNDLE_IDENTIFIER).NotificationExtension` |
+| Share Extension | `SHARE_BUNDLE_IDENTIFIER` | `$(APP_BUNDLE_IDENTIFIER).ShareExtension` |
+
+#### Checklist for New Targets
+
+- [ ] Add bundle ID variable to `Base.xcconfig`
+- [ ] Set `baseConfigurationReference` to Debug/Release xcconfig
+- [ ] Use `$(VARIABLE)` for `PRODUCT_BUNDLE_IDENTIFIER`
+- [ ] Use `$(DEVELOPMENT_TEAM)` for team
+- [ ] Create entitlements with `$(APP_GROUP_IDENTIFIER)` if sharing data
+- [ ] Add to `AppIdentifiers.swift` if Swift code needs the identifier
+- [ ] Register App ID in Apple Developer Portal (uses same App Group)
+
 ### Migration
 
 To migrate to a new developer account, edit **one file** (`Base.xcconfig`):
@@ -613,7 +695,7 @@ COMPANY_IDENTIFIER = com.newcompany
 DEVELOPMENT_TEAM = NEW_TEAM_ID
 ```
 
-Then clean build (⇧⌘K) and rebuild. Everything updates automatically.
+Then clean build (⇧⌘K) and rebuild. Everything updates automatically—including all extension targets.
 
 
 ## Dynamic Type Instructions